Transcript
LTC5551 300MHz to 3.5GHz Ultra-High Dynamic Range Downconverting Mixer Description
Features +36dBm Input IP3 n 2.4dB Conversion Gain n Low Noise Figure: <10dB n +18dBm Ultra High Input P1dB n 670mW Power Consumption n 2.5V to 3.6V Operation n 50Ω Single-Ended RF and LO Inputs n 0dBm LO Drive Level n Low Power Mode n –40°C to 105°C Operation (T ) C n Small Solution Size n Enable Pin n 16-Lead (4mm × 4mm) QFN Package
The LTC®5551 is a 2.5V to 3.6V mixer optimized for RF downconverting mixer applications that require very high dynamic range. The LTC5551 covers the 300MHz to 3.5GHz RF Frequency range with LO frequency range of 200MHz to 3.5GHz. The LTC5551 provides very high IIP3 and P1dB with low power consumption. A typical application is a basestation receiver covering 700MHz to 2.7GHz frequency range. The RF input can be matched for a wide range of frequencies and the IF is usable up to 1GHz.
n
A low power mode is activated by pulling the ISEL pin high, reducing the power consumption by about 1/3, however, with a corresponding reduction in IIP3 to approximately +29dBm. The mixer can also be turned on or off by using the EN pin.
Applications n n n n n n n
The LTC5551’s high level of integration minimizes the total solution cost, board space and system level variation, while providing the highest dynamic range for demanding receiver applications.
GSM, LTE, LTE-Advanced Basestations Repeaters DPD Observation Receiver Public Safety Radios, Military and Defense Avionics Radios and TCAS Transponders Active Phased-Array Antennas White-Space Radio Receiver
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 8558605.
Typical Application Wideband Receiver 1nF VCC 3.3V
0.56µF
22pF
BPF
470nH
470nH
475Ω
475Ω
LTC6416 IF AMP
Mixer Conversion Gain and IIP3 vs IF Frequency (Low-Side LO)
LTC2208 39
ADC
6
36 33
1nF
IIP3
5
RF = 1770MHz TO 1970MHz LO = 1700MHz ZIF = 200Ω
4
2.2pF RFIN
IF – IF
LTC5551
RF
LO LO
7.5nH EN (0V/3.3V) VCC 3.3V
3.9pF
LTC6946 SYNTH LO 1700MHz
24 21 18
VCC
3
GC
15 12 9
BIAS
EN
27
GC (dB)
IF+
IIP3 (dBm)
30
2 NORMAL POWER MODE LOW POWER MODE
1 70 90 110 130 150 170 190 210 230 250 270 IF FREQUENCY (MHz) 5551 TA01b
5551 TA01a
0.56µF
22pF 5551fa
For more information www.linear.com/LTC5551
1
LTC5551 Absolute Maximum Ratings
Pin Configuration
(Note 1)
Supply Voltage (VCC, IF+, IF –)......................................4V Enable Input Voltage (EN).................–0.3V to VCC + 0.3V Power Select Voltage (ISEL).............–0.3V to VCC + 0.3V LO Input Power (0.2GHz to 3.5GHz).................... +10dBm LO Input DC Voltage ............................................. ±0.1V RF Input Power (0.3GHz to 3.5GHz)....................+20dBm RF Input DC Voltage................................................ ±0.1V TEMP Diode Continuous DC Input Current..............10mA TEMP Diode Input Voltage......................................... ±1V IFBIAS Voltage..........................................................2.5V Operating Temperature Range (TC)......... –40°C to 105°C Storage Temperature Range................... –65°C to 150°C Junction Temperature (TJ)..................................... 150°C
GND
IF–
IF+
IFBIAS
TOP VIEW
16 15 14 13 TP 1
12 TEMP
RF 2
11 GND
17 GND
CT 3
10 LO
GND 4 6
7
8
EN
VCC
VCC
ISEL
9 5
GND
UF PACKAGE 16-LEAD (4mm × 4mm) PLASTIC QFN TJMAX = 150°C, θJC = 6°C/W EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
CAUTION: This part is sensitive to electrostatic discharge (ESD). It is very important that proper ESD precautions be observed when handling the LTC5551.
Order Information LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
CASE TEMPERATURE RANGE
LTC5551IUF#PBF
LTC5551IUF#TRPBF
5551
16-Lead (4mm × 4mm) Plastic QFN
–40°C to 105°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
2
5551fa
For more information www.linear.com/LTC5551
LTC5551 AC Electrical Characteristics
The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TC = 25°C. VCC = 3.3V, EN = High, ISEL = Low, PLO = 0dBm, unless otherwise noted. Test circuit shown in Figure 1. (Notes 2, 3) PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
LO Input Frequency Range
l
200 to 3500
MHz
RF Input Frequency Range
l
300 to 3500
MHz
5 to 1000
MHz
IF Output Frequency Range
Requires External Matching
RF Input Return Loss
ZO = 50Ω, 1100MHz to 2700MHz, X1 = 7.5nH, C1 = 2.2pF
LO Input Return Loss
ZO = 50Ω, 1000MHz to 3500MHz, C2 = 3.9pF
IF Output Impedance
Differential at 153MHz
LO Input Power
LO = 200MHz to 3500MHz
LO to RF Leakage
LO = 200MHz to 3500MHz
< –25
dBm
LO to IF Leakage
LO = 200MHz to 3500MHz
< –21
dBm
RF to LO Isolation
RF = 300MHz to 3500MHz
>55
dB
RF to IF Isolation
RF = 300MHz to 3500MHz
>23
dB
>12
dB
>12 950Ω || 1.2pF
dB R||C
–6
0
6
dBm
The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TC = 25°C. VCC = 3.3V, EN = High, PLO = 0dBm, PRF = 0dBm (0dBm/tone for 2-tone tests), unless otherwise noted. Test circuit shown in Figure 1. (Notes 2, 3) 0.3GHz to 3.5GHz Downmixer Application: IF = 153MHz, ISEL = Low, unless otherwise noted. (Notes 2, 3) PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Power Conversion Gain
RF = 400MHz, High Side LO RF = 850MHz, High Side LO RF = 1950MHz, Low Side LO RF = 2700MHz, Low Side LO
3.2 2.8 2.4 1.7
dB dB dB dB
Conversion Gain Flatness
RF = 1870MHz ±100MHz, LO = 1700MHz, IF = 170 ±100MHz
±0.2
dB
Conversion Gain vs Temperature
TC = –40°C to 105°C, RF = 1950MHz, Low Side LO
–0.013
dB/°C
2-Tone Input 3rd Order Intercept (∆f = 2MHz)
RF = 400MHz, High Side LO RF = 850MHz, High Side LO RF = 1950MHz, Low Side LO RF = 2700MHz, Low Side LO
33.2 35.2 35.5 38.1
dBm dBm dBm dBm
2-Tone Input 2nd Order Intercept (∆f = 154MHz = fIM2)
RF = 400MHz (477MHz/323MHz), LO = 553MHz RF = 850MHz (927MHz/773MHz), LO = 1053MHz RF = 1950MHz (2027MHz/1873MHz), LO = 1797MHz RF = 2700MHz (2777MHz/2623MHz), LO = 2547MHz
65.8 68.2 58.4 57.1
dBm dBm dBm dBm
SSB Noise Figure
RF = 400MHz, High Side LO RF = 850MHz, High Side LO RF = 1950MHz, Low Side LO RF = 2700MHz, Low Side LO
10.6 9.1 9.7 10.9
dB dB dB dB
SSB Noise Figure Under Blocking
RF = 850MHz, High Side LO, 750MHz Blocker at 5dBm RF = 1950MHz, Low Side LO, 2050MHz Blocker at 5dBm
16.5 16.9
dB dB
1/2 IF Output Spurious Product (fRF Offset to Produce Spur at fIF = 153MHz)
850MHz: RF = 926.5MHz at –3dBm, LO = 1003MHz 1950MHz: RF = 1873.5MHz at –3dBm, LO = 1797MHz
–66 –68
dBc dBc
1/3 IF Output Spurious Product (fRF Offset to Produce Spur at fIF = 153MHz)
850MHz: RF = 952MHz at –3dBm, LO = 1003MHz 1950MHz: RF = 1848MHz at –3dBm, LO = 1797MHz
–97 –93
dBc dBc
Input 1dB Compression
RF = 400MHz, High Side LO RF = 850MHz, High Side LO RF = 1950MHz, Low Side LO RF = 2700MHz, Low Side LO
17.1 17.8 18.0 18.7
dBm dBm dBm dBm
5551fa
For more information www.linear.com/LTC5551
3
LTC5551 AC Electrical Characteristics
The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 3.3V, EN = High, PLO = 0dBm, PRF = 0dBm (0dBm/tone for 2-tone tests), unless otherwise noted. Test circuit shown in Figure 1. (Notes 2, 3) Low Power Mode, 0.3GHz to 3.5GHz Downmixer Application: IF = 153MHz, ISEL = High (Notes 2, 3) PARAMETER
CONDITIONS
Power Conversion Gain
RF = 400MHz, High Side LO RF = 850MHz, High Side LO RF = 1950MHz, Low Side LO RF = 2700MHz, Low Side LO
MIN
TYP 3.0 2.7 2.4 1.7
MAX
UNITS dB dB dB dB
Input 3rd Order Intercept
RF = 400MHz, High Side LO RF = 850MHz, High Side LO RF = 1950MHz, Low Side LO RF = 2700MHz, Low Side LO
27.3 28.0 29.3 29.7
dBm dBm dBm dBm
SSB Noise Figure
RF = 400MHz, High Side LO RF = 850MHz, High Side LO RF = 1950MHz, Low Side LO RF = 2700MHz, Low Side LO
9.8 8.2 8.3 9.2
dB dB dB dB
Input 1dB Compression
RF = 400MHz, High Side LO RF = 850MHz, High Side LO RF = 1950MHz, Low Side LO RF = 2700MHz, Low Side LO
14.8 16.2 16.7 17.7
dBm dBm dBm dBm
DC Electrical Characteristics
The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TC = 25°C. VCC = 3.3V, EN = High, ISEL = Low, unless otherwise noted. Test circuit shown in Figure 1. (Note 2) PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
2.5
3.3
3.6
VDC
234 100
mA mA µA
100
mA mA µA
Power Supply Requirements Supply Voltage (VCC)
l
Supply Current (ISEL = Low)
EN = High, No LO Applied EN = High, with LO Applied EN = Low
148 204
Supply Current – Low Power Mode (ISEL = High)
EN = High, No LO Applied EN = High, with LO Applied EN = Low
128 142
Enable Logic Input (EN) Input High Voltage (On)
l
Input Low Voltage (Off)
l
1.2
VDC
–30
0.3
VDC
100
µA
Input Current
–0.3V to VCC + 0.3V
Turn On Time
LO Applied
0.4
µs
Turn Off Time
LO Applied
0.5
µs
Power Select Logic Input (ISEL) Input High Voltage (Low Power Mode)
l
Input Low Voltage (High Power Mode) Input Current
1.2
VDC
l
–0.3V to VCC + 0.3V
–30
0.3
VDC
100
µA
Temperature Sensing Diode (TEMP) DC Voltage at TJ = 25°C
IIN = 10µA IIN = 80µA
Voltage Temperature Coefficient
IIN = 10µA IIN = 80µA
4
726 783 l l
–1.72 –1.53
mV mV mV/°C mV/°C 5551fa
For more information www.linear.com/LTC5551
LTC5551 Electrical Characteristics Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LTC5551 is guaranteed functional over the –40°C to 105°C case temperature range.
Note 3: SSB Noise Figure measurements performed with a small-signal noise source, bandpass filter and 6dB matching pad on RF input, bandpass filter and 6dB matching pad on the LO input, bandpass filter on the IF output and no other RF signals applied.
Typical DC Performance Characteristics
Supply Current vs Supply Voltage, LO = 1800MHz at 0dBm
Supply Current vs Supply Voltage, No LO Applied 180
250 ISEL = LOW
200
ICC (mA)
ICC (mA)
ISEL = HIGH
100 80 60
50
VCC = 3.5V VCC = 3.3V VCC = 3.1V 35 10 60 85 CASE TEMPERATURE (°C)
110
40
VCC = 3.5V VCC = 3.3V VCC = 3.1V
20 0 –40
–15
35 10 60 85 CASE TEMPERATURE (°C)
Supply Current vs VCC LO = 1800MHz at 0dBm
ISEL = HIGH
100 TC = 105°C TC = 85°C TC = 25°C TC = –40°C
50
0 300 700 1100 1500 1900 2300 2700 3100 3500 LO FREQUENCY (MHz) 5551 G03
Supply Current vs VCC LO = 1800MHz at TC = 25°C
220
220
190
190
160
130
110
150
5551 G02
5551 G01
ICC (mA)
–15
ISEL = LOW
120
ISEL = HIGH
ICC (mA)
ICC (mA)
250
140
100
0 –40
Supply Current vs LO Frequency (PLO = 0dBm)
ISEL = LOW
160
200 150
EN = High, Test circuit shown in Figure 1.
TC = 105°C TC = 85°C TC = 25°C TC = –40°C
100 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 VCC (V)
160
130 LO = 6dBm LO = 0dBm LO = –6dBm
100 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 VCC (V)
5551 G04
5551 G05
5551fa
For more information www.linear.com/LTC5551
5
LTC5551 Typical AC Performance Characteristics
1100MHz to 2700MHz application. VCC = 3.3V, EN = High, ISEL = Low, TC = 25°C, PLO = 0dBm, PRF = 0dBm (0dBm/tone for two-tone IIP3 tests, ∆f = 2MHz), IF = 153MHz, unless otherwise noted. Test circuit shown in Figure 1.
40
36
TC = 85°C TC = 25°C TC = –40°C
NF
GC 1.3
IIP3
32
IIP3
28
2.5
16 NF
12 8
GC
–6
–4
–2 0 2 4 LO INPUT POWER (dBm)
18 15
NF
12 9 6
IIP3 (dBm), NF (dB), GC (dB)
21
GC
3 0 1.1
1.3
2.5
GC –4
–2 0 2 4 LO INPUT POWER (dBm)
32
28 TC = 85°C TC = 25°C TC = –40°C
24 20 16 NF
12 8
GC
0
2.7
–6
–4
IIP3
28 24
16
NF
12 8 GC
0
6
TC = 85°C TC = 25°C TC = –40°C
20
4
–2 0 2 4 LO INPUT POWER (dBm)
5551 G09
–6
–4
–2 0 2 4 LO INPUT POWER (dBm)
RF Isolation vs Frequency
20
6 5551 G11
5551 G10
Input P1dB vs RF Frequency (Low Side LO)
6
2550MHz Conversion Gain, IIP3 and NF vs LO Power (High Side LO)
IIP3
4
1.5 1.7 1.9 2.1 2.3 RF FREQUENCY (GHz)
8
36
32 TC = 85°C TC = 25°C TC = –40°C
NF
12
5551 G08
IIP3 (dBm), NF (dB), GC (dB)
IIP3
24
16
–6
36
27
20
1950MHz Conversion Gain, IIP3 and NF vs LO Power (High Side LO)
36 30
24
0
6
TC = 85°C TC = 25°C TC = –40°C
28
5551 G07
Conversion Gain, IIP3 and NF vs RF Frequency (High Side LO) 33
IIP3
32
4
5551 G06
IIP3 (dBm), NF (dB), GC (dB)
36
20
0
2.7
TC = 85°C TC = 25°C TC = –40°C
24
4
1.5 1.7 1.9 2.1 2.3 RF FREQUENCY (GHz)
2550MHz Conversion Gain, IIP3 and NF vs LO Power (Low Side LO)
IIP3 (dBm), NF (dB), GC (dB)
39 36 33 30 27 24 21 18 15 12 9 6 3 0 1.1
1950MHz Conversion Gain, IIP3 and NF vs LO Power (Low Side LO)
IIP3 (dBm), NF (dB), GC (dB)
IIP3 (dBm), NF (dB), GC (dB)
Conversion Gain, IIP3 and NF vs RF Frequency (Low Side LO)
LO Leakage vs LO Frequency 0
70
19 60
15 14 13
TC = 105°C TC = 85°C TC = 25°C TC = –40°C
11 10 1.1
1.3
1.5 1.7 1.9 2.1 2.3 RF FREQUENCY (GHz)
2.5
2.7
5551 G12
LO LEAKAGE (dBm)
16
12
6
–10
RF-LO
17 ISOLATION (dB)
INPUT P1dB (dBm)
18
50 40 30
1.3
1.5 1.7 1.9 2.1 2.3 RF FREQUENCY (GHz)
–30 LO-RF –40 –50
RF-IF 20 1.1
LO-IF
–20
2.5
2.7
5551 G13
–60 1.1
1.3
1.5 1.7 1.9 2.1 2.3 LO FREQUENCY (GHz)
2.5
2.7
5551 G14
5551fa
For more information www.linear.com/LTC5551
LTC5551 Typical AC Performance Characteristics
1100MHz to 2700MHz application. VCC = 3.3V, EN = High, ISEL = Low, TC = 25°C, PLO = 0dBm, PRF = 0dBm (0dBm/tone for two-tone IIP3 tests, ∆f = 2MHz), IF = 153MHz, unless otherwise noted. Test circuit shown in Figure 1. Single-Tone IF Output Power, 2 × 2 and 3 × 3 Spurs vs RF Input Power 20
20
0
–10 –20 RF1 = 1949MHz RF2 = 1951MHz LO = 1797MHz
–40 –50 –60 –70
IM3
–80
–100 –10 –7
–30 –40 2RF-2LO RF = 1873.5MHz
–50 –60 –70
IM5
–90
–20
3RF-3LO RF = 1848MHz
–80
–4 –1 2 5 8 11 14 RF INPUT POWER (dBm/TONE)
–90
17
–9
–6
–3 0 3 6 9 12 15 RF INPUT POWER (dBm/TONE)
5551 G15
SSB NF (dB)
14 12
8 –25
PLO = –6dBm PLO = 0dBm PLO = 6dBm –20
–15 –10 –5 0 5 RF BLOCKER POWER (dBm)
RF = 1950MHz LOW SIDE LO HIGH SIDE LO
24 21 18 15 NF
12 9 6
GC
3
–4
10
5
32
4 RF = 1950MHz LOW SIDE LO HIGH SIDE LO 3
29 26 23
GC
20
40
40 30 20 10 0 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 CONVERSION GAIN (dB) 5551 G21
35 30
2
P1dB
17 14
1
NF
0 8 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 VCC SUPPLY VOLTAGE (V)
5551 G19
RF = 1950MHz
6
IIP3
5551 G20
1950MHz IIP3 Histogram 85°C 25°C –40°C
–2 0 2 4 LO INPUT POWER (dBm)
5551 G17
11
0 –40 –25 –10 5 20 35 50 65 80 95 110 CASE TEMPERATURE (°C)
DISTRIBUTION (%)
DISTRIBUTION (%)
50
–6
35
27
1950MHz Conversion Gain Histogram 60
3RF-3LO RF = 1848MHz
–90
Conversion Gain, IIP3, P1dB and SSB NF vs Supply Voltage
IIP3
30
5551 G18
70
–80
GC (dB)
16
2RF-2LO RF = 1873.5MHz
38
33
18
10
–70
–100
36
IIP3 (dBm), NF (dB), GC (dB)
20
–60
Conversion Gain, IIP3 and SSB NF vs Temperature
RF = 1950MHz LO = 1797MHz BLOCKER = 2050MHz
RF = 1950MHz PRF = –3dBm LO = 1797MHz
5551 G16
SSB Noise Figure vs RF Blocker Level 22
18
IIP3 (dBm), P1dB (dBm), NF (dB)
–30
LO = 1797MHz
–10
1950MHz SSB NF Histogram 40
RF = 1950MHz 85°C 25°C –40°C
RF = 1950MHz
35
85°C 25°C –40°C
30 DISTRIBUTION (%)
0
–50
IFOUT RF = 1950MHz
10
IFOUT OUTPUT POWER (dBm)
OUTPUT POWER/TONE (dBm)
10
2 × 2 and 3 × 3 Spurs vs LO Power
RELATIVE SPUR LEVEL (dBc)
2-Tone IF Output Power, IM3 and IM5 vs RF Input Power
25 20 15
25 20 15
10
10
5
5
0 33.2 33.6 34 34.4 34.8 35.2 35.8 36 36.4 IIP3 (dBm)
0 8.8
5551 G22
9.2
10.4 10.8 9.6 10 SSB NOISE FIGURE (dB)
11.2 5551 G23
5551fa
For more information www.linear.com/LTC5551
7
LTC5551 Typical AC Performance Characteristics
1100MHz to 2700MHz application. Low Power Mode. VCC = 3.3V, EN = High, ISEL = High, TC = 25°C, PLO = 0dBm, PRF = 0dBm (0dBm/tone for two-tone IIP3 tests, ∆f = 2MHz), IF = 153MHz, unless otherwise noted. Test circuit shown in Figure 1. Conversion Gain, IIP3 and NF vs RF Frequency (High Side LO) 31
28
28 LOW POWER MODE 85°C 25°C –40°C
19 16 13
NF
10 7
GC
4 1.3
19 16 13
NF
10
2.5
GC
1 1.1
2.7
19
35
1.3
1.5 1.7 1.9 2.1 2.3 RF FREQUENCY (GHz)
INPUT P1dB (dBm)
14 13 LOW POWER MODE LOW SIDE LO HIGH SIDE LO 1.3
1.5 1.7 1.9 2.1 2.3 RF FREQUENCY (GHz)
2.5
2.7
IIP3
29
3 GC
23 20
2
17
–30 –40 –50 –60 –70
IM3
10 LO-RF
–40 1.1
1.3
1.5 1.7 1.9 2.1 2.3 LO/RF FREQUENCY (GHz)
2.5
LOW POWER MODE LO = 1797MHz
–10 –20 –30 –40 –50
2RF-2LO RF = 1873.5MHz
–90 –10 –8 –6 –4 –2 0 2 4 6 8 10 12 14 16 RF INPUT POWER (dBm/TONE)
–80 –10 –7
–10 2.7
5551 G29
2 × 2 and 3 × 3 Spurs vs LO Power –50
–70
8
LO-IF
IFOUT RF = 1950MHz
–80
5551 G30
30
–30
Single Tone IF Output Power, 2 × 2 and 3 × 3 Spurs vs RF Input Power
0
50
RF-IF
–20
NF
–60
IM5
LOW POWER MODE
5551 G28
LOW POWER MODE
RF1 = 1949MHz RF2 = 1951MHz LO = 1797MHz
70
–10
0 8 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 VCC SUPPLY VOLTAGE (V)
10
0
RF-LO
1
11
6
0
P1dB
14
OUTPUT POWER (dBm)
OUTPUT POWER/TONE (dBm)
–20
2 4 –2 0 LO INPUT POWER (dBm)
5551 G26
20 IFOUT
–4
LO Leakage and RF Isolation
26
20 0
–6
LOW POWER MODE RF = 1950MHz LOW SIDE LO 4 HIGH SIDE LO
32
2-Tone IF Output Power, IM3 and IM5 vs RF Input Power
–10
7
2.7
5
5551 G27
10
NF
RF ISOLATION (dB)
15
11
2.5
GC (dB)
16
IIP3 (dBm), P1dB (dBm), NF (dB)
38
17
2 LOW POWER MODE RF = 1950MHz LOW SIDE LO HIGH SIDE LO 1
16
Conversion Gain, IIP3, P1dB and NF vs Supply Voltage
20
10 1.1
19
5551 G25
Input P1dB vs RF Frequency
12
22
10
5551 G24
18
3 GC
13
7 4
1.5 1.7 1.9 2.1 2.3 RF FREQUENCY (GHz)
IIP3
25
LOW POWER MODE 85°C 25°C –40°C
22
4
28
RELATIVE SPUR LEVEL (dBc)
1 1.1
IIP3
25
LO LEAKAGE (dBm)
22
IIP3 (dBm), NF (dB), GC (dB)
IIP3
25
31
NF (dB), IIP3 (dBm)
31
1950MHz Conversion Gain, IIP3 and NF vs LO Power
GC (dB)
IIP3 (dBm), NF (dB), GC (dB)
Conversion Gain, IIP3 and NF vs RF Frequency (Low Side LO)
–60
2RF-2LO RF = 1873.5MHz
LOW POWER MODE RF = 1950MHz PRF = –3dBm LO = 1797MHz
–70 –80
3RF-3LO RF = 1848MHz
–90
3RF-3LO RF = 1848MHz –4 –1 2 5 8 11 14 RF INPUT POWER (dBm/TONE)
17
5551 G31
–100
–6
–4
–2 0 2 4 LO INPUT POWER (dBm)
6 5551 G32
5551fa
For more information www.linear.com/LTC5551
LTC5551 Typical AC Performance Characteristics
300MHz to 650MHz application. VCC = 3.3V, EN = High, ISEL = Low, TC = 25°C, PLO = 0dBm, PRF = 0dBm (0dBm/tone for two-tone IIP3 tests, ∆f = 2MHz), IF = 153MHz, unless otherwise noted. Test circuit shown in Figure 1. Conversion Gain, IIP3 and NF vs RF Frequency (High Side LO) 33
IIP3
85°C 25°C –40°C
30 27 24 21 18 15
NF
12 9 GC
6 3
31
85°C 25°C –40°C
27 24 21
NF
12
350
400 450 500 550 RF FREQUENCY (MHz)
600
6
GC
0 300
650
350
400 450 500 550 RF FREQUENCY (MHz)
600
IIP3
28
12
GC
25
3
22
RF = 400MHz LOW SIDE LO 2 HIGH SIDE LO
19 16 NF
LOW SIDE LO HIGH SIDE LO 350
400 450 500 550 RF FREQUENCY (MHz)
600
1
7
–6
650
–4
–2 0 2 4 LO INPUT POWER (dBm)
Conversion Gain, IIP3 and SSB NF vs Temperature
18 12
NF
9 6 3
RF-IF
–20
40
LO-IF
GC
20
23 20 17
P1dB
14
1
NF
–40 300
350
IFOUT
0 –10 –20 –30
RF1 = 399MHz RF2 = 401MHz LO = 553MHz
–40 –50 –60 –70 –80
LO-RF
5551 G39
3 RF = 400MHz LOW SIDE LO HIGH SIDE LO 2
20
60
–30
0 –40 –25 –10 5 20 35 50 65 80 95 110 CASE TEMPERATURE (°C)
26
10
–10 LO LEAKAGE (dBm)
21
GC
5551 G38
RF-LO RF = 400MHz LOW SIDE LO HIGH SIDE LO
4
29
0 8 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 VCC SUPPLY VOLTAGE (V)
80
IIP3
24
IIP3
2-Tone IF Output Power, IM3 and IM5 vs RF Input Power
0
27
15
6
0
RF ISOLATION (dB)
IIP3 (dBm), NF (dB), GC (dB)
30
32
LO Leakage and RF Isolation
36
0 650
5
5551 G37
5551 G36
33
600
11
10
OUTPUT POWER/TONE (dBm)
10 300
4
IIP3 (dBm), P1dB (dBm), NF (dB)
NF (dB), IIP3 (dBm)
INPUT P1dB (dBm)
35
13
11
400 450 500 550 RF FREQUENCY (MHz)
GC (dB)
13
350
1
38
GC (dB)
LOW POWER MODE
14
2 NF
Conversion Gain, IIP3, P1dB and NF vs Supply Voltage 5
31
16
3
5551 G35
34 NORMAL POWER MODE
17
4
7 300
650
37
19
5
GC
16
400MHz Conversion Gain, IIP3 and NF vs LO Power
20
6
19
5551 G34
Input P1dB vs Frequency
15
22
10
5551 G33
18
LOW POWER MODE ISEL = HIGH LOW SIDE LO HIGH SIDE LO
13
9 3
0 300
7
25
18 15
8 IIP3
28
IIP3
30
IIP3 (dBm), NF (dB)
36
33
IIP3 (dBm), NF (dB), GC (dB)
36
Conversion Gain, IIP3 and NF vs RF Frequency
GC (dB)
IIP3 (dBm), NF (dB), GC (dB)
Conversion Gain, IIP3 and NF vs RF Frequency (Low Side LO)
400 450 500 550 600 LO/RF FREQUENCY (MHz)
0 650
5551 G40
–90 –10 –7
IM3 IM5
–4 –1 2 5 8 11 14 RF INPUT POWER (dBm/TONE)
17
5551 G41
5551fa
For more information www.linear.com/LTC5551
9
LTC5551 Typical AC Performance Characteristics
500MHz to 1100MHz application. VCC = 3.3V, EN = High, ISEL = Low, TC = 25°C, PLO = 0dBm, PRF = 0dBm (0dBm/tone for two-tone IIP3 tests, ∆f = 2MHz), IF = 153MHz, unless otherwise noted. Test circuit shown in Figure 1.
31
33 30
85°C 25°C –40°C
NF
24 21 18 15 NF
12 6
GC
0 500
1100
IIP3
3 RF = 850MHz 2 LOW SIDE LO HIGH SIDE LO 1
NF –6
–4
–2 0 2 4 LO INPUT POWER (dBm)
6 5551 G46
0
GC (dB)
NF (dB), IIP3 (dBm)
4
GC
20
8
19
600
700 800 900 1000 RF FREQUENCY (MHz)
NF (dB), IIP3 (dBm)
14 13 12
4
GC
26
3
23 20
RF = 850MHz 2 LOW SIDE LO HIGH SIDE LO 1
17
–6
–4
–2 0 2 4 LO INPUT POWER (dBm)
5551 G45
26
GC
23 20
2 P1dB
17 14
1 NF
5551 G47
2-Tone IF Output Power, IM3 and IM5 vs RF Input Power
LO Leakage and RF Isolation 80
0
20
60
–10
RF-IF
–20
40 LO-IF
–30
20 LO-RF
–40 500
600
IFOUT
10
RF-LO
LO LEAKAGE (dBm)
IIP3 (dBm), NF (dB), GC (dB)
6
RF = 850MHz 4 LOW SIDE LO HIGH SIDE LO 3
IIP3
29
0 8 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 VCC SUPPLY VOLTAGE (V)
0
RF ISOLATION (dB)
10
32
5551 G46
Conversion Gain, IIP3 and SSB NF vs Temperature
5551 G48
5
11
NF
8
0 1100
38
29
11
1100
39 36 IIP3 33 30 27 RF = 850MHz 24 LOW SIDE LO 21 HIGH SIDE LO 18 15 12 NF 9 6 GC 3 0 –40 –25 –10 5 20 35 50 65 80 95 110 CASE TEMPERATURE (°C)
900 1000 700 800 RF FREQUENCY (MHz)
35
IIP3
14 LOW SIDE LO HIGH SIDE LO 700 800 900 1000 RF FREQUENCY (MHz)
600
1
GC (dB)
LOW POWER MODE
600
2
5551 G44
5
32
17
11
3
Conversion Gain, IIP3, P1dB and NF vs Supply Voltage
38 35
NORMAL POWER MODE
4
NF
7 500
1100
GC (dB)
INPUT P1dB (dBm)
5
35 32 29 26 23
5
GC
16
10
IIP3 (dBm), P1dB (dBm), NF (dB)
38
17 14 11
15
19
850MHz Conversion Gain, IIP3 and NF vs LO Power
20
16
22
5551 G43
Input P1dB vs RF Frequency
18
6 LOW POWER MODE ISEL = HIGH LOW SIDE LO HIGH SIDE LO
13
9 3
700 800 900 1000 RF FREQUENCY (MHz)
7
IIP3
25
OUTPUT POWER/TONE (dBm)
600
85°C 25°C –40°C
27
GC
8
28
IIP3 (dBm), NF (dB)
IIP3
IIP3
5551 G42
10 500
Conversion Gain, IIP3 and NF vs RF Frequency
36
IIP3 (dBm), NF (dB), GC (dB)
39 36 33 30 27 24 21 18 15 12 9 6 3 0 500
Conversion Gain, IIP3 and NF vs RF Frequency (High Side LO)
GC (dB)
IIP3 (dBm), NF (dB), GC (dB)
Conversion Gain, IIP3 and NF vs RF Frequency (Low Side LO)
0 –10 –20 –30 –40
RF1 = 849MHz RF2 = 851MHz LO = 1003MHz
–50 –60 –70
IM3 IM5
–80 700 800 900 1000 LO/RF FREQUENCY (MHz)
0 1100
5551 G49
–90 –10 –7
–4 –1 2 5 8 11 14 RF INPUT POWER (dBm/TONE)
17
5551 G50
5551fa
For more information www.linear.com/LTC5551
LTC5551 Typical AC Performance Characteristics
2300MHz to 3500MHz application. VCC = 3.3V, EN = High, ISEL = Low, TC = 25°C, PLO = 0dBm, PRF = 0dBm (0dBm/tone for two-tone IIP3 tests, ∆f = 2MHz), IF = 153MHz, unless otherwise noted. Test circuit shown in Figure 1. Conversion Gain, IIP3 and NF vs RF Frequency (High Side LO)
39
36
35
33
23 19 NF
11 7
GC
3 –1 2.3
2.5
3.3
85°C 25°C –40°C
24 21 18 15
NF
12 6
2.5
2.7 2.9 3.1 RF FREQUENCY (GHz)
39 NORMAL POWER MODE
NF (dB), IIP3 (dBm)
INPUT P1dB (dBm)
14 13 12 LOW SIDE LO HIGH SIDE LO 2.7 2.9 3.1 RF FREQUENCY (GHz)
3.3
30 24
RF = 2.7GHz 3 LOW SIDE LO HIGH SIDE LO
21
2
27
GC
18 12 9
3.5
1
NF
–6
–4
–2 0 2 4 LO INPUT POWER (dBm)
24 21
1
P1dB
18 15
0
NF
5551 G56
75
20
60
LO LEAKAGE (dBm)
–10 RF-IF
45
LO-IF
–30 –40
IFOUT
10
RF-LO
–20
2
GC
2-Tone IF Output Power, IM3 and IM5 vs RF Input Power
0
NF
27
–1 9 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 VCC SUPPLY VOLTAGE (V)
0
30
15
LO-RF
GC
RF ISOLATION (dB)
IIP3 (dBm), NF (dB), GC (dB)
6
3
RF = 2.7GHz LOW SIDE LO HIGH SIDE LO
30
LO Leakage and RF Isolation
IIP3
RF = 2700MHz LOW SIDE LO HIGH SIDE LO
IIP3
33
5551 G55
Conversion Gain, IIP3 and SSB NF vs Temperature
–3 3.5
3.3
4
12
5551 G54
39 36 33 30 27 24 21 18 15 12 9 6 3 0 –40 –25
3.1 2.7 2.9 RF FREQUENCY (GHz)
36 4
15
2.5
2.5
GC (dB)
15
–2
NF
39
GC (dB)
16
–1
Conversion Gain, IIP3, P1dB and NF vs Supply Voltage 5
33 LOW POWER MODE
0
5551 G53
IIP3
36
18
11
16
7 2.3
3.3
1
LOW POWER MODE ISEL = HIGH LOW SIDE LO HIGH SIDE LO
2.7GHz Conversion Gain, IIP3 and NF vs LO Power
20
10 2.3
19
2
5551 G52
Input P1dB vs RF Frequency
17
GC
22
10
GC
5551 G51
19
3
13
9
0 2.3
3.5
4
IIP3
25
27
3
2.7 2.9 3.1 RF FREQUENCY (GHz)
5
28
OUTPUT POWER/TONE (dBm)
15
30
IIP3 (dBm), NF (dB)
85°C 25°C –40°C
31 IIP3
IIP3 (dBm), P1dB (dBm), NF (dB)
27
IIP3 (dBm), NF (dB), GC (dB)
IIP3
31
Conversion Gain, IIP3 and NF vs RF Frequency
GC (dB)
IIP3 (dBm), NF (dB), GC (dB)
Conversion Gain, IIP3 and NF vs RF Frequency (Low Side LO)
0 –10 –20 –30 –40
RF1 = 2699MHz RF2 = 2701MHz LO = 2547MHz
–50 –60
IM3
–70
IM5
–80
–10 5 20 35 50 65 80 95 110 CASE TEMPERATURE (°C) 5551 G57
–50 2.3
2.5
2.9 3.1 3.3 2.7 LO/RF FREQUENCY (GHz)
0 3.5 5551 G58
–90
–8
–5
–2 1 4 7 10 13 RF INPUT POWER (dBm/TONE)
16
5551 G59
5551fa
For more information www.linear.com/LTC5551
11
LTC5551 Pin Functions TP (Pin 1): Test Point. It is used for manufacture measurement only. It is recommended to be connected to ground.
a regulated 2.5V to 3.6V supply, with bypass capacitors located close to the pin. Typical current consumption is 70mA through these pins.
RF (Pin 2): Single-Ended Input for the RF Signal. This pin is internally connected to the primary side of the RF input transformer, which has low DC resistance to ground. A series DC-blocking capacitor should be used to avoid damage to the integrated transformer when DC voltage is present at the RF input. The RF input impedance is matched under the condition that the LO input is driven with a 0dBm ±6dB source between 0.2GHz and 3.5GHz.
ISEL (Pin 8): Low Power Select Pin. When this pin is pulled low (<0.3V) or left open, the mixer is biased at the normal current level for best RF performance. When greater than 1.2V is applied, the mixer operates at reduced current mode, which provides reasonable performance at lower power consumption. This pin has an internal pull-down resistor. LO (Pin 10): Single-Ended Input for the Local Oscillator. This pin is internally connected to the primary side of the RF input transformer, which has low DC resistance to ground. A series DC blocking capacitor should be used to avoid damage to the integrated transformer when DC voltage is present at the LO input.
CT (Pin 3): RF Transformer Secondary Center-Tap. This pin must be connected to ground with minimum parasitic resistance and inductance to complete the Mixer’s DC current path. Typical DC current is 80mA with LO disabled and 134mA when LO signal is applied. GND (Pins 4, 9, 11, 13, Exposed Pad Pin 17): Ground. These pins must be soldered to the RF ground plane on the circuit board. The exposed pad metal of the package provides both electrical contact to ground and good thermal contact to the printed circuit board.
TEMP (Pin 12): Temperature Sensing Diode. This pin is connected to the anode of a diode that may be used to measure the die temperature, by forcing a current and measuring the voltage. IF – (Pin 14) and IF + (Pin 15): Open-Collector Differential Outputs for the IF Amplifier. These pins must be connected to a DC supply through impedance matching inductors, or a transformer center-tap. Typical DC current consumption is 67mA into each pin.
EN (Pin 5): Enable Pin. When the input voltage is greater than 1.2V, the mixer is enabled. When the input voltage is less than 0.3V or left open, the mixer is disabled. Typical input current is less than 30μA. This pin has an internal pull-down resistor.
IFBIAS (Pin 16): This Pin Allows Adjustment of the IF Amplifier Current. Typical DC voltage is 2.1V. This pin should be left floating for optimum performance.
VCC (Pins 6, 7): Power Supply Pins. These pins are internally connected and must be externally connected to
Block Diagram 16
15
14
IFBIAS IF +
17
IF –
EXPOSED PAD
IF AMP 2
3
TEMP
LO
RF LO AMP
12
10
CT BIAS
5
EN
6
VCC
7
VCC
6
ISEL 5551 BD
GND PINS ARE NOT SHOWN
12
5551fa
For more information www.linear.com/LTC5551
LTC5551 Test Circuit T1 4:1
IFOUT 153MHz 50Ω C9
L1
L2
R1
R2
C8
VCC C4
C5
16
15
IFBIAS 1 GND
14
IF+
13
IF –
GND TEMP 12
LTC5551
C1
RFIN 50Ω
2 RF X1
GND 11
X2
17 GND
C2 LO 10
3 CT
C3
4 GND
EN 0V TO 3.3V
GND 9
EN
VCC
VCC
ISEL
5
6
7
8
VCC 3.1V TO 3.5V
C6
C7
ISEL 0V TO 3.3V
5551 F01
RF
0.015"
GND TBD BOARD BIAS STACK-UP GND (NELCO N4000-13)
0.062" 0.015"
APPLICATION
LOIN 50Ω
RF MATCH
LO MATCH
IF TRANSFORMER
RF (MHz)
LO
X1
C1
X2
C2
C3
T1
VENDOR
300 to 650
HS
15nH
15pF
15pF
15pF
8.2pF
TC4-1W-7ALN+
Mini-Circuits
500 to 1100
HS
13nH
6.8pF
4.7pF
8.2pF
2.2pF
WBC4-6TLB
Coilcraft
1100 to 2700
LS, HS
7.5nH
2.2pF
–
3.9pF
–
TC4-1W-7ALN+
Mini-Circuits
2300 to 3500
LS, HS
1.2pF
22pF
2.2nH
3.9pF
–
TC4-1W-7ALN+
Mini-Circuits
REF DES
VALUE
SIZE
VENDOR
REF DES
VALUE
SIZE
VENDOR
C4, C6
0.56µF
0603
Murata
R1, R2
475Ω, 1%
0402
Vishay
C5, C7
22pF
0402
AVX
L1, L2
470nH, 2%
0603
Coilcraft 0603LS
C8, C9
1nF
0402
AVX
Figure 1. Standard Downmixer Test Circuit Schematic (153MHz IF)
5551fa
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13
LTC5551 Applications Information Introduction The LTC5551 consists of a high linearity double-balanced mixer core, IF buffer amplifier, LO buffer amplifier and bias/enable circuits. See the Block Diagram section for a description of each pin function. The RF and LO inputs are single-ended. The IF output is differential. Low side or high side LO injection can be used. The evaluation circuit, shown in Figure 1, utilizes bandpass IF output matching and an IF transformer to realize a 50Ω single-ended IF output. The evaluation board layout is shown in Figure 2.
For the RF input to be matched, the LO input must be driven. Using components listed in Figure 1, the RF input can be matched from 300MHz to 3.5GHz. The measured RF input return loss is shown in Figure 4 for LO frequencies of 0.5GHz, 1.0GHz. 1.8GHz and 2.8GHz. These LO frequencies correspond to the lower, middle and upper values of the LO range. The RF input impedance and input reflection coefficient, versus RF frequency, is listed in Table 1. The reference plane for this data is Pin 2 of the IC, with no external matching, and the LO is driven at 1.8GHz. LTC5551 TO MIXER C1
RFIN
2 X1
RF
X2
3
CT
5551 F03
Figure 3. RF Input Schematic Figure 2. Evaluation Board Layout
RF Input
The secondary winding of the RF transformer is internally connected to the mixer core. The center-tap of the transformer secondary is connected to Pin 3 (CT). Pin 3 needs to be connected to ground with a minimum parasitic resistance and inductance.
RF PORT RETURN LOSS (dB)
5
The mixer’s RF input, shown in Figure 3, is connected to the primary winding of an integrated transformer. A 50Ω match can be realized with a π-network as shown in Figures 1 and 3. The primary side of the RF transformer is DC-grounded internally and the DC resistance of the primary is approximately 4Ω. A DC blocking capacitor is needed if the RF source has DC voltage present.
14
0
10
LO = 0.5GHz LO = 1.0GHz LO = 1.8GHz LO = 2.8GHz
1100MHz to 2700MHz MATCHING
15 20 25 30
500MHz to 1100MHz MATCHING 300MHz to 650MHz MATCHING
2300MHz to 3500MHz MATCHING
35 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.3 3.6 RF FREQUENCY (GHz) 5551 F04
Figure 4. RF Input Return Loss
5551fa
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LTC5551 Applications Information Table 1. RF Input Impedance and S11 (at Pin 2, No External Matching, LO Input Driven at 1.8GHz) S11
FREQUENCY (GHz)
INPUT IMPEDANCE
MAG
ANGLE
0.3
7.6 + j8.4
0.74
160.4
0.7
11.7 + j15.2
0.65
144.5
1.1
17.7 + j 22.2
0.55
127.4
1.5
29.3 + j27.8
0.41
107.4
1.9
46.7 + j21.8
0.22
85.8
2.3
49.6 – j1.3
0.01
–106.3
2.7
31.1 – j9.0
0.26
–148.2
3.1
18.2 – j1.8
0.47
–175.2
3.5
11.8 + j8.4
0.63
159.8
LO Input The mixer’s LO input circuit, shown in Figure 5, consists of a balun transformer and a two-stage high speed limiting differential amplifier to drive the mixer core. The LTC5551’s LO amplifiers are optimized for the 200MHz to 3.5GHz LO frequency range. LO frequencies above or below this frequency range may be used with degraded performance. The mixer’s LO input is directly connected to the primary winding of an integrated transformer. The LO is 50Ω matched from 1GHz to 3.5GHz with a single 3.9pF series
capacitor on the input. Matching to LO frequencies below 1GHz is easily accomplished by adding shunt capacitor C3 shown in Figure 5. Measured LO input return loss is shown in Figure 6. The nominal LO input level is 0dBm although the limiting amplifiers will deliver excellent performance over a ±6dB input power range. LO input power of –9dBm may be used with slightly degraded performance. The LO input impedance and input reflection coefficient, versus frequency, is shown in Table 2. Table 2. LO Input Impedance vs Frequency (at Pin 10, No External Matching) INPUT IMPEDANCE
MAG
ANGLE
0.3
4.8 + j12.0
0.84
152.7
0.7
13.4 + j28.1
0.67
118.5
1.1
32.7 + j39.1
0.47
88.6
1.5
56.8 + j31.1
0.29
61.5
1.9
62.8 + j9.3
0.14
31.4
2.3
54.1 – j1.4
0.04
–18.3
2.7
45.1 – j1.4
0.05
–163.6
3.1
39.8 + j3.6
0.12
158.6
3.5
37.2 + j10.4
0.19
134.1
0
LO BUFFER
LO 10
TO MIXER
C2
C3
4mA BIAS
5
EN
6
VCC
7
LOIN LO PORT RETURN LOSS (dB)
LTC5551
S11
FREQUENCY (GHz)
5
C2 = 15pF, C3 = 8.2pF C2 = 8.2pF, C3 = 2.2pF C2 = 3.9pF, C3 OPEN
10 15 20 25 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.3 3.6 LO FREQUENCY (GHz)
VCC 5551 F05
5551 F06
Figure 5. LO Input Schematic
Figure 6. LO Input Return Loss
5551fa
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15
LTC5551 Applications Information IF Output The IF amplifier, shown in Figure 7, has differential opencollector outputs (IF+ and IF –), and a pin for modifying the internal bias (IFBIAS). The IF outputs must be biased at the supply voltage (VCC), which is applied through matching inductors L1 and L2. Alternatively, the IF outputs can be biased through the center tap of a transformer. Each IF output pin draws approximately 67mA of DC supply current (134mA total). For the highest performance, high-Q wire-wound chip inductors are recommended for L1 and L2. Low cost multilayer chip inductors may be substituted, with a slight degradation in performance.
C9 L1
16 15 IF+ IFBIAS
IF –
CIF
5551 F08
Figure 8. IF Output Small-Signal Model Table 3. IF Output Impedance vs Frequency
954 || –j1442 (1.2pF)
140
950 || –j848 (1.2pF)
190
945 || –j681 (1.2pF)
L2
240
942 || –j539 (1.2pF)
R2
380
938 || –j338 (1.2pF)
456
926 || –j281 (1.2pF)
VCC LTC5551
RIF
90
C8
R1
14
DIFFERENTIAL OUTPUT IMPEDANCE (RIF || XIF (CIF))
4:1
R3 (OPTION TO REDUCE DC POWER)
IF +
FREQUENCY (MHz)
T1
IFOUT
15
LTC5551
C4
14 IF –
Transformer-Based Bandpass IF Matching VCC 4mA
The IF output can be matched using the bandpass IF matching shown in Figures 1 and 7. L1 and L2 resonate with the internal IF output capacitance at the desired IF frequency. The value of L1, L2 is calculated as follows:
IF AMP
BIAS 5551 F07
Figure 7. IF Amplifier Schematic with Transformer-Based Bandpass Match
For optimum single-ended performance, the differential IF outputs must be combined through an external IF transformer or discrete IF balun circuit. The evaluation board (see Figures 1 and 2) uses a 4:1 ratio IF transformer for impedance transformation and differential to single-ended transformation. It is also possible to eliminate the IF transformer and drive differential filters or amplifiers directly. The IF output impedance can be modeled as 950Ω in parallel with 1.2pF at IF frequencies. An equivalent smallsignal model is shown in Figure 8. Frequency-dependent differential IF output impedance is listed in Table 3. This data is referenced to the package pins (with no external components) and includes the effects of IC and package parasitics.
16
L1, L2 = 1/[(2 π fIF)2 • 2 • CIF] where CIF is the internal IF capacitance (listed in Table 3). Values of L1 and L2 are tabulated in Figure 1 for various IF frequencies. For IF Frequency below 80MHz, the inductor values become unreasonably high and the high pass impedance matching network described in a later section is preferred, due to its lower inductor values. Table 4 summarizes the optimum IF matching inductor values vs IF center frequency, to be used in the standard downmixer test circuit shown in Figure 1. The inductor values listed are less than the ideal calculated values due to the additional capacitance of the 4:1 transformer. Measured IF output return losses are shown in Figure 9. 5551fa
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LTC5551 Applications Information Table 4. Bandpass Matching Elements Values vs IF Frequency
Highpass IF Matching
L1, L2 vs IF Frequencies
The highpass IF matching circuits shown in Figure 10 can be used when higher conversion gain than that from the standard demoboard is desired. The highpass matching network will have less IF bandwidth than the bandpass matching. It also use smaller inductance values; an advantage when designing for IF center frequency well lower than 80MHz.
IF (MHz)
L1, L2 (nH)
COMMENTS
120
810
Coilcraft 0603 LS
153
470
Coilcraft 0603 LS
240
180
Coilcraft 0603 CS
305
120
Coilcraft 0603 CS
380
56
Coilcraft 0603 CS
456
33
Coilcraft 0603 CS
The resistors R1 and R2 which are connected between the IF+ and IF– is used to assist the IF impedance matching. A lower value of R1, R2 will help improve the IF return loss and broaden the IF bandwidth. However, it will results in lower conversion gain with minor impact to linearity and noise figure performances. Other 4:1 transformers can be used to replace the TC41-7ALN+ that is used in the standard demoboards. The insertion loss and parasitics of the transformer will impact the overall circuit performance. For IF frequency higher than 300MHz, the TC4-1-17LN+ from Mini-Circuits or the WBC4-6TLB from Coilcraft is preferred.
Referring to the small-signal output network schematic in Figure 10, the reactive matching element values (L1, L2, C8 and C9) are calculated using the following equations. The source resistance (RS) is the parallel combination of external resistors R1 + R2 and the internal IF resistance, RIF taken from Table 3. The differential load resistance (RL) is typically 200Ω, but can be less. CIF, the IF output capacitance, is taken from Table 3. Choosing RS in the 380Ω to 450Ω range will yield power conversion gains around 4dB.
RETURN LOSS (dB)
5
15 L1, L2 = 470nH L1, L2 = 120nH L1, L2 = 56nH L1, L2 = 33nH
20 25
50 100 150 200 250 300 350 400 450 500 IF FREQUENCY (MHz) 5551 F09
(R1=R2)
(RS /RL −1) YL =Q /RS + (ωIF •CIF ) L1,L2 =1/ (2 • YL • ωIF ) C7,C8 = 2 / (Q •RL • ωIF )
(RS >RL )
Q=
0
10
RS =RIF 2 •R1
To demonstrate the highpass impedance transformer output matching, these equations were used to calculate the element values for a 80MHz IF frequency and 200Ω differential load resistance. The measured performance with L1, L2 = 330nH, C8, C9 = 15pF is shown in Figure 11. The test conditions are: PRF = –6dBm, PLO = 0dBm with low side LO injection.
Figure 9. IF Output Return Loss Bandpass Matching with 4:1 Transformer
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17
LTC5551 Applications Information T1 4:1 C9
IFOUT
L1
L2
R1
R2
C8
VCC C4 15
LTC5551
14
IF+
IF –
RIF CIF
5551 F10
Figure 10. IF Output Circuit for Highpass Matching Element Value Calculations
38
10
36
9 8 IIP3
32
7
30
6
26
5 4
24 22 20 1.1
GC (dB)
IIP3 (dBm)
34
R1, R2 OPEN R1, R2 = 1kΩ 1.3
GC
1.5 1.7 1.9 2.1 2.3 RF FREQUENCY (GHz)
3 2.5
2 2.7
5551 F11
Figure 11. Performance Using 80MHz Highpass IF Matching Network
18
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LTC5551 Applications Information Wideband Differential IF Output Wide IF bandwidth and high input 1dB compression are obtained by reducing the IF output resistance with resistors R1 and R2. This will reduce the mixer’s conversion gain, but will not degrade the IIP3 or noise figure. The IF matching shown in Figure 12 uses 249Ω resistors and 470nH supply chokes to produce a wideband 200Ω differential output. This differential output is suitable for driving a wideband differential amplifier, filter, or a wideband 4:1 transformer.
The complete test circuit, shown in Figure 13, uses resistive impedance matching attenuators (L-pads) on the evaluation board to transform each 100Ω IF output to 50Ω. An external 0°/180° power combiner is then used to convert the 100Ω differential output to 50Ω single-ended, to facilitate measurement. Measured conversion gain and IIP3 at the 200Ω differential output are plotted in Figure 14. As shown, the conversion gain is flat within 1dB over the 50MHz to 490MHz IF output frequency range. 5
38 36 IIP3
34
249Ω
IF+
100Ω
470nH
249Ω
3
28 26
20 0 50 90 130 170 210 250 290 330 370 410 450 490 IF FREQUENCY (MHz)
18
5551 F12
270pF
1
22
100Ω
470nH
2
GC
24
VCC
IF–
30
GC (dB)
LTC5551
IIP3 (dBm)
200Ω LOAD
270pF
4
32
5551 F14
Figure 12. Wideband 200Ω Differential Output
LO 1.8GHz 0dBm
Figure 14. Conversion Gain and IIP3 vs IF Output Frequency for Wideband 200Ω Differential IF
L-PADS AND 180° COMBINER FOR 50Ω SINGLE-ENDED MEASUREMENT
3.9pF LO
270pF
LTC5551 RF 1.85GHz TO 2.29GHz
2.2pF
IF+
LO
249Ω
7.5nH
IF
EN
71.5Ω
470nH IFOUT 200Ω
RF
EN
69.8Ω
249Ω IF–
BIAS
IF+ 50Ω
22pF
470nH
1MHz TO 500MHz COMBINER 0° OUT
IF–
69.8Ω
270pF
50Ω
180°
IFOUT 50Ω
71.5Ω
VCC 3.3V 10nF
0.56µF
5551 F13
Figure 13. Test Circuit for Wideband 200Ω Differential Output
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19
LTC5551 Applications Information The IFBIAS pin (Pin 16) is available for reducing the DC current consumption of the IF amplifier, at the expense of reduced performance. This pin should be left open-circuited for optimum performance. The internal bias circuit produces a 4mA reference for the IF amplifier, which causes the amplifier to draw approximately 134mA. If resistor R3 is connected to Pin 16 as shown in Figure 7, a portion of the reference current can be shunted to ground, resulting in reduced IF amplifier current. For example, R3 = 1kΩ will shunt away 1.5mA from Pin 16 and the IF amplifier current will be reduced to approximately 90mA. The nominal, open-circuit DC voltage at Pin 16 is 2.1V. Table 5 lists RF performance at 1950MHz vs IF amplifier current. Table 5. Mixer Performance with Reduced IF Amplifier Current (RF = 1950MHz, Low Side LO, IF = 153MHz, VCC = 3.3V) R3 (kΩ)
ICC (mA)
GC (dB)
IIP3 (dBm)
P1dB (dBm)
NF (dB)
OPEN
204
2.4
35.5
18.0
9.7
4.7
194
2.4
35.0
17.9
9.4
2.2
186
2.4
34.2
17.8
9.2
1.0
164
2.4
31.9
17.3
LTC5551 VCC
7
ISEL
8
BIAS
5551 F15
Figure 15. ISEL Interface Schematic LTC5551 6
5
VCC
EN
BIAS
5551 F16
Figure 16. Enable Input Circuit
8.7
(RF = 1950MHz, High Side LO, IF = 153MHz, VCC = 3.3V) R3 (kΩ)
ICCIF (mA)
GC (dB)
IIP3 (dBm)
P1dB (dBm)
NF (dB)
OPEN
204
2.4
33.0
17.9
10.5
4.7
194
2.3
32.6
17.8
10.2
ISEL
ICC (mA)
GC (dB)
IIP3 (dBm)
P1dB (dBm)
NF (dB)
Table 6. Performance Comparison – Low Power vs High Power Mode RF = 1950MHz, Low Side LO, IF = 153MHz, EN = High
2.2
186
2.3
32.1
17.6
9.9
Low
204
2.4
35.5
18.0
9.7
1.0
164
2.3
30.5
17.0
9.4
High
139
2.4
29.3
16.7
8.3
Low Power Mode
Enable Interface
The LTC5551 can be set to low power mode using a digital voltage applied to the ISEL pin (Pin 8). This allows the flexibility to reduce current when lower RF performance is acceptable. Figure 15 shows a simplified schematic of the ISEL pin interface. When ISEL is set low (<0.3V), the mixer operates at maximum DC current. When ISEL is set high (>1.2V), the DC current is reduced, thus reducing power consumption. When floating, the ISEL is pulled low by an internal pull-down resistor, and operates at maximum supply current. The performance in low power mode and nominal power mode are compared in Table 6.
Figure 16 shows a simplified schematic of the EN pin interface. To enable the chip, the EN voltage must be higher than 1.2V. The EN voltage at the pin should never exceed the power supply voltage (VCC) by more than 0.3V. If this should occur, the supply current could be sourced through the ESD diode, potentially damaging the IC.
20
If the EN pin is left floating, its voltage will be pulled low by the internal pull-down resistor and the chip will be disabled.
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LTC5551 Applications Information Temperature Diode
Supply Voltage Ramping
The LTC5551 provides an on-chip diode at Pin 12 (TEMP) for chip temperature measurement. Pin 12 is connected to the anode of an internal ESD diode with its cathode connected to internal ground. The chip temperature can be measured by injecting a constant DC current into Pin 12 and measuring its DC voltage. The voltage vs temperature coefficient of the diode is about –1.72mV/°C with 10µA current injected into the TEMP pin. Figure 17 shows a typical temperature-voltage behavior when 10µA and 80µA currents are injected into Pin 12.
Fast ramping of the supply voltage can cause a current glitch in the internal ESD protection circuits. Depending on the supply inductance, this could result in a supply voltage transient that exceeds the maximum rating. A supply voltage ramp time of greater than 1ms is recommended.
TEMPERATURE DIODE VOLTAGE (mV)
900 850 800
Table 7. IF Output Spur Levels (dBc)
80µA
700 650 600 550 500 450 400 –40
–20
0
20 40 60 TEMPERATURE (°C)
Mixer spurious output levels versus harmonics of the RF and LO are tabulated in Table 7. The spur levels were measured on a standard evaluation board using the test circuit shown in Figure 1. The spur frequencies can be calculated using the following equation: fSPUR = (M • fRF)–(N • fLO)
10µA
750
Spurious Output Levels
80
100 5551 F17
Figure 17. TEMP Diode Voltage vs Junction Temperature (TJ)
RF = 1950MHz, PRF = 0dBm, PLO = 0dBm, IF = 153MHz, Low Side LO, VCC = 3.3V, EN = High, ISEL = Low, TC = 25°C N 0 1 2 3 4 5 6 7 8 9 0 –26 –36 –40 –40 –61 –70 –57 –60 * 1 –28 0 –43 –26 –60 –43 –64 –49 –62 –63 2 –83 –66 –70 –69 –83 * * –81 * –79 M * * * * * * 3 * –81 * * 4 * * * * * * * * * * 5 * * * * * * * * * * 6 –84 * * * * * * * * * 7 –82 * * –84 * * * * * * *Less than –85dBc
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21
LTC5551 Package Description
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
UF Package 16-Lead Plastic QFN (4mm × 4mm)
(Reference LTC DWG # 05-08-1692 Rev Ø)
0.72 ±0.05
4.35 ±0.05 2.15 ±0.05 2.90 ±0.05 (4 SIDES)
PACKAGE OUTLINE 0.30 ±0.05 0.65 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS BOTTOM VIEW—EXPOSED PAD 4.00 ±0.10 (4 SIDES)
0.75 ±0.05
R = 0.115 TYP
15
PIN 1 NOTCH R = 0.20 TYP OR 0.35 × 45° CHAMFER
16 0.55 ±0.20
PIN 1 TOP MARK (NOTE 6)
1 2.15 ±0.10 (4-SIDES)
2
(UF16) QFN 10-04
0.200 REF 0.00 – 0.05
0.30 ±0.05 0.65 BSC
NOTE: 1. DRAWING CONFORMS TO JEDEC PACKAGE OUTLINE MO-220 VARIATION (WGGC) 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE
22
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LTC5551 Revision History REV
DATE
DESCRIPTION
A
12/13
Added U.S. Patent number
PAGE NUMBER 1
Corrected transformer T1 part number
13
5551fa
Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. For more information www.linear.com/LTC5551
23
LTC5551 Typical Application Wideband 100Ω Differential IF Output Matching 1nF
3.9pF LO 2.2pF RF 7.5nH
LTC5551
110Ω
560nH
2MHz TO 2000MHz COMBINER 0° IFOUT 50Ω
OUT IF–
110Ω
VCC
560nH 1nF
IF– 50Ω
180°
39
6
36
5
33
4
30
3
27
2
IIP3
NORMAL POWER MODE 1 LOW POWER MODE 0
24 21 18
22pF
12 3.3V 10nF
0.56µF
–1
GC
15
GC (dB)
RF 1.85GHz TO 2.51GHz
IF+
IF+ 50Ω
IIP3 (dBm)
LO 1.8GHz 0dBm
Conversion Gain and IIP3 vs IF Frequency (Low Side LO)
–2
–3 50 110 170 230 290 350 410 470 530 590 650 710 IF FREQUENCY (MHz) 5551 TA02b
5551 TA02a
Related Parts PART NUMBER DESCRIPTION Mixers and Modulators LT®5527 400MHz to 3.7GHz, 5V Downconverting Mixer LT5557 400MHz to 3.8GHz, 3.3V Downconverting Mixer LTC559x 600MHz to 4.5GHz Dual Downconverting Mixer Family LTC5569 300MHz to 4GHz, 3.3V Dual Active Downconverting Mixer LTC554x 600MHz to 4GHz, 5V Downconverting Mixer Family LT5578 400MHz to 2.7GHz Upconverting Mixer LT5579 1.5GHz to 3.8GHz Upconverting Mixer LTC5588-1 200MHz to 6GHz I/Q Modulator LTC5585 700MHz to 3GHz Wideband I/Q Demodulator Amplifiers LTC6430-15 High Linearity Differential IF Amp LTC6431-15 High Linearity Single-Ended IF Amp LTC6412 31dB Linear Analog VGA LT5554 Ultralow Distortion IF Digital VGA RF Power Detectors LT5538 40MHz to 3.8GHz Log Detector LT5581 6GHz Low Power RMS Detector LTC5582 40MHz to 10GHz RMS Detector LTC5583 Dual 6GHz RMS Power Detector ADCs LTC2208 16-Bit, 130Msps ADC LTC2153-14 14-Bit, 310Msps Low Power ADC RF PLL/Synthesizer with VCO LTC6946-1/ Low Noise, Low Spurious Integer-N PLL with Integrated VCO LTC6946-2/ LTC6946-3
24 Linear Technology Corporation
COMMENTS 2.3dB Gain, 23.5dBm IIP3 and 12.5dB NF at 1900MHz, 5V/78mA Supply 2.9dB Gain, 24.7dBm IIP3 and 11.7dB NF at 1950MHz, 3.3V/82mA Supply 8.5dB Gain, 26.5dBm IIP3, 9.9dB NF, 3.3V/380mA Supply 2dB Gain, 26.8dBm IIP3 and 11.7dB NF, 3.3V/180mA Supply 8dB Gain, >25dBm IIP3 and 10dB NF, 3.3V/200mA Supply 27dBm OIP3 at 900MHz, 24.2dBm at 1.95GHz, Integrated RF Output Transformer 27.3dBm OIP3 at 2.14GHz, NF = 9.9dB, 3.3V Supply, Single-Ended LO and RF Ports 31dBm OIP3 at 2.14GHz, –160.6dBm/Hz Noise Floor >530MHz Demodulation Bandwidth, IIP2 Tunable to >80dBm, DC Offset Nulling 20MHz to 2GHz Bandwidth, 15.2dB Gain, 50dBm OIP3, 3dB NF at 240MHz 20MHz to 1.7GHz Bandwidth, 15.5dB Gain, 47dBm OIP3, 3.3dB NF at 240MHz 35dBm OIP3 at 240MHz, Continuous Gain Range –14dB to 17dB 48dBm OIP3 at 200MHz, 2dB to 18dB Gain Range, 0.125dB Gain Steps ±0.8dB Accuracy Over Temperature, –72dBm Sensitivity, 75dB Dynamic Range 40dB Dynamic Range, ±1dB Accuracy Over Temperature, 1.5mA Supply Current ±0.5dB Accuracy Over Temperature, ±0.2dB Linearity Error, 57dB Dynamic Range Up to 60dB Dynamic Range, ±0.5dB Accuracy Over Temperature, >50dB Isolation 78dBFS Noise Floor, >83dB SFDR at 250MHz 68.8dBFS SNR, 88dB SFDR, 401mW Power Consumption 373MHz to 5.79GHz, –157dBc/Hz WB Phase Noise Floor, –100dBc/Hz Closed-Loop Phase Noise
1630 McCarthy Blvd., Milpitas, CA 95035-7417 For more information www.linear.com/LTC5551 (408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com/LTC5551
5551fa LT 1213 REV A • PRINTED IN USA
LINEAR TECHNOLOGY CORPORATION 2013
