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LTC1541/LTC1542 Micropower Op Amp, Comparator and Reference FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ U ■ DESCRIPTIO The LTC®1541/LTC1542 combine a micropower amplifier, comparator and bandgap reference (LTC1541) in an 8-pin package. The part operates from a single 2.5V to 12.6V or dual ±1.25V to ± 6.3V supply with a typical supply current of 5µA. Both the op amp and comparator feature a common mode input voltage range that extends from the negative supply to within 1.3V of the positive supply. The op amp output stage swings from rail-to-rail. The comparator’s inverting input is internally connected to the reference output (LTC1541). Quiescent Current: 5µA Typ Outputs Swing Rail-to-Rail Low Op Amp Offset Voltage: 700µV Max Reference Output Drives 0.01µF Capacitor Internal 1.2V ±0.4% Reference Output (LTC1541) Low Input Bias Current: 1nA Max Reference Output Can Source Up to 2mA Internal ±2.25mV Comparator Hysteresis Comparator and Op Amp Input Range Includes Ground Op Amp Capable of Driving Up to 1000pF Load Unity-Gain Stable and 12kHz Bandwidth 2.5V to 12.6V Supply Voltage Range Daisy-Chained Control Outputs Pin Compatible Upgrade for MAX951/MAX953 Available in 3mm x 3mm x 0.8mm DFN Package The reference output voltage is 1.2V ±1% over the extended temperature range. The output can drive a bypass capacitor of up to 0.01µF without any oscillations. It can also source up to 2mA and sink up to 20µA. U APPLICATIO S ■ ■ ■ ■ ■ ■ The op amp is internally compensated to be unity-gain stable with typical GBW at 12kHz and slew rate of 8V/ms. The comparator has ±2.25mV of internal hysteresis to ensure clean output switching, even with slow moving input signals. Battery- or Solar-Powered Systems Automotive Keyless Entry Low Frequency, Local Area Alarms/Detectors Infrared Receivers for Remote Controls Smoke Detectors and Safety Sensors GSM Portable Phones The LTC1541/LTC1542 are available in MSOP and SO-8 packages. For space-limited applications, the LTC1541/ LTC1542 are available in a 3mm x 3mm low profile (0.8mm) dual fine-pitch leadless package (DFN). , LTC and LT are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. U TYPICAL APPLICATIO Op Amp VOS Distribution, VCM = 2.5V, SO-8 Package Total of 839 Units Pilot Light Flame Detector with Low-Battery Lockout VIN = 3.6V TO 9V 50 1k – + 10k 100k 1N457 10M 3 + 8 OUTPUT HIGH = “ON” OUTPUT LOW = “OFF” 1 2.2µF 1/2 LTC1541 2 – ICC = 7µA AT VIN = 5V SCR LOAD 2M 5 1M + 1/2 LTC1541 6 7 LOW BATTERY VCC = 5V VSS = 0V 40 30 20 10 – 2M 10k 2N3904 PERCENT OF UNITS (%) 1N457 TYPE R 0 –600 1.2V INTERNAL REFERENCE 0 300 –300 INPUT OFFSET VOLTAGE (µV) 600 1541/42 TA02 VN2222 1541/42 • TA01 15412fd 1 LTC1541/LTC1542 AXI U RATI GS U W W W ABSOLUTE (Note 1) Supply Voltage ........................................................ 13V Input Voltage .............................................– 0.3V to 13V Output Voltage ...........................................– 0.3V to 13V Output Short-Circuit Duration .......................... Indefinite Storage Temperature Range ................. – 65°C to 150°C (DD Package) ................................... – 65°C to 125°C Operating Temperature Range (Note 7) .. – 40°C to 85°C Specified Temperature Range (Note 8) ... – 40°C to 85°C Lead Temperature (Soldering, 10 sec).................. 300°C U U W PACKAGE/ORDER I FOR ATIO TOP VIEW TOP VIEW AMPOUT 1 8 VCC AMPIN – 2 7 COMPOUT AMPIN+ 3 6 REF VSS 4 5 COMPIN+ TOP VIEW AMPOUT AMPIN – AMPIN+ VSS 1 2 3 4 8 7 6 5 VCC COMPOUT REF COMPIN + MS8 PACKAGE 8-LEAD PLASTIC MSOP DD PACKAGE 8-LEAD (3mm × 3mm) PLASTIC DFN AMPOUT 1 8 VCC AMPIN– 2 7 COMPOUT 3 6 REF VSS 4 5 COMPIN + AMPIN + S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 150°C, θJA = 250°C/W TJMAX = 125°C, θJA = 160°C/W (NOTE 6) UNDERSIDE METAL CONNECTED TO V– (PCB CONNECTION OPTIONAL) TJMAX = 150°C, θJA = 150°C/W ORDER PART NUMBER DD PART MARKING* ORDER PART NUMBER MS8 PART MARKING ORDER PART NUMBER S8 PART MARKING LTC1541CDD LTC1541IDD LAAT LTC1541CMS8 LTC1541IMS8 LTBE LTADW LTC1541CS8 LTC1541IS8 1541 1541I TOP VIEW TOP VIEW AMPOUT 1 8 VCC AMPIN – 2 7 COMPOUT AMPIN+ 3 6 COMPIN– VSS 4 5 COMPIN + TOP VIEW AMPOUT AMPIN – AMPIN+ VSS 1 2 3 4 8 7 6 5 VCC COMPOUT COMPIN – COMPIN + MS8 PACKAGE 8-LEAD PLASTIC MSOP DD PACKAGE 8-LEAD (3mm × 3mm) PLASTIC DFN TJMAX = 150°C, θJA = 250°C/W TJMAX = 125°C, θJA = 160°C/W (NOTE 6) UNDERSIDE METAL CONNECTED TO V– (PCB CONNECTION OPTIONAL) AMPOUT 1 8 VCC AMPIN– 2 7 COMPOUT AMPIN+ 3 6 COMPIN – VSS 4 5 COMPIN + S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 150°C, θJA = 150°C/W ORDER PART NUMBER DD PART MARKING* ORDER PART NUMBER MS8 PART MARKING ORDER PART NUMBER S8 PART MARKING LTC1542CDD LTC1542IDD LAAU LTC1542CMS8 LTC1542IMS8 LTDE LTADX LTC1542CS8 LTC1542IS8 1542 1542I Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/ Consult LTC Marketing for parts specified with wider operating temperature ranges. *Temperature grades are identified by a label on the shipping container. 15412fd 2 LTC1541/LTC1542 ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, VSS = 0V, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS 12.6 V Power Supply VCC Supply Voltage Range ICC Supply Current (Note 2) ● 2.5 Commercial Grade Industrial Grade ● ● 5 10 16 17 µA µA µA (SO-8) Commercial Grade (SO-8) Industrial Grade (SO-8) ● ● 1 1.5 2.0 mV mV mV (MSOP)(DFN) Commercial Grade (MSOP)(DFN) Industrial Grade (MSOP)(DFN) ● ● 1.2 2.0 2.5 mV mV mV 2.8 3.8 mV mV 1 nA VCC – 1.3V V Comparator VOS VTRIP Input Offset Voltage (Note 3) Trip Point (Note 4) ● IIN Input Leakage Current (Note 5) ● VCM Input Common Mode Range ● CMRR Common Mode Rejection Ratio PSRR Power Supply Rejection Ratio 1.7 1 2.25 0.01 VSS VCM = VSS to (VCC – 1.3V) (LTC1542) Commercial Grade Industrial Grade ● ● 0.7 0.8 0.9 mV/V mV/V mV/V VCC = 3V to 12V Commercial Grade (SO-8) Industrial Grade (SO-8) ● ● 0.25 0.30 0.35 mV/V mV/V mV/V tPD Propagation Delay Overdrive = 10mV Overdrive = 100mV 20 8 VOH Output High Voltage IOUT = – 2mA ● VCC – 0.2V VOL Output Low Voltage IOUT = 1.8mA ● No Load (SO-8) Commercial Grade (SO-8) Industrial Grade (SO-8) ● ● 1.195 1.190 1.188 No Load (MSOP) Commercial Grade (MSOP) Industrial Grade (MSOP) ● ● No Load (DFN) Commercial Grade (DFN) Industrial Grade (DFN) ● ● µs µs V VSS + 0.3V V 1.200 1.205 1.210 1.212 V V V 1.190 1.185 1.183 1.200 1.210 1.215 1.217 V V V 1.185 1.180 1.178 1.200 1.215 1.220 1.222 V V V 2 0.2 6 1.5 5 Reference (LTC1541 Only) VREF Reference Voltage ∆VREF Load Regulation ISOURCE = 2mA ISINK = 10µA en Voltage Noise 0.1Hz to 10Hz Input Offset Voltage VCM = 2.5V (SO-8) Commercial Grade (SO-8) Industrial Grade (SO-8) ● ● 0.7 1.25 1.65 mV mV mV VCM = 2.5V (MSOP) (DFN) Commercial Grade (MSOP) (DFN) Industrial Grade (MSOP) (DFN) ● ● 1.00 1.75 2.0 mV mV mV ● ● 16 mV mV mV µVP-P Op Amp VOS 15412fd 3 LTC1541/LTC1542 ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, VSS = 0V, unless otherwise noted. SYMBOL PARAMETER CONDITIONS IB Input Bias Current VCM = 2.5V AVOL Large-Signal Gain AMPOUT = 0.5V to 4.5V, No Load AMPOUT = 0.5V to 4.5V, RLOAD = 100k Commercial Grade Industrial Grade MIN ● ● ● 80 60 38 35 TYP MAX 0.01 1 1000 500 UNITS nA V/mV V/mV V/mV V/mV GBW Gain Bandwidth AV = 1V/V 12 kHz SR Slew Rate AV = 1V/V 8 V/ms VCM Input Common Mode Range CMRR Common Mode Rejection Ratio PSRR VOH VOL ISOURCE ISINK en Power Supply Rejection Ratio Output High Voltage Output Low Voltage ● VCC – 1.3V V VCM = VSS to (VCC – 1.3V) Commercial Grade Industrial Grade ● ● 0.5 0.6 0.6 mV/V mV/V mV/V VCC = 3V to 12V Commercial Grade Industrial Grade ● ● 0.19 0.21 0.23 mV/V mV/V mV/V RLOAD = 100k to VSS Commercial Grade Industrial Grade ● ● RLOAD = 100k to VCC Commercial Grade Industrial Grade ● ● Output Source Current VCC – 0.07 VCC – 0.10 VCC – 0.12 V V V VSS + 0.05 VSS + 0.10 VSS + 0.12 V V V 0.9 0.7 1.8 ● mA mA 1.3 0.9 1.8 ● mA mA Output Sink Current Input Noise Voltage VSS fO = 0.1Hz to 10Hz 3 µVP-P The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 3V, VSS = 0V, unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Power Supply VCC Supply Voltage Range ICC Supply Current (Note 2) ● 2.5 4.5 12.6 V µA µA µA Commercial Grade Industrial Grade ● ● 9.5 15 16 (SO-8) Commercial Grade (SO-8) Industrial Grade (SO-8) ● ● 1.0 1.5 2.0 mV mV mV (MSOP)(DFN) Commercial Grade (MSOP)(DFN) Industrial Grade (MSOP)(DFN) ● ● 1.2 2.0 2.5 mV mV mV 2.90 3.90 mV mV 1 nA VCC – 1.3 V Comparator VOS VTRIP Input Offset Voltage (Note 3) Trip Point (Note 4) ● IIN Input Leakage Current (Note 5) ● VCM Input Common Mode Range ● CMRR Common Mode Rejection Ratio VCM = VSS to (VCC – 1.3V) (LTC1542) Commercial Grade Industrial Grade ● ● 1.80 1.00 2.35 0.01 VSS 0.8 0.9 1.0 mV/V mV/V mV/V 15412fd 4 LTC1541/LTC1542 ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 3V, VSS = 0V, unless otherwise noted. SYMBOL PARAMETER CONDITIONS PSRR Power Supply Rejection Ratio VCC = 3V to 12V Commercial Grade Industrial Grade MIN TYP ● ● tPD Propagation Delay Overdrive = 10mV Overdrive = 100mV VOH Output High Voltage IOUT = – 2mA ● VOL Output Low Voltage IOUT = 1.8mA ● No Load (SO-8) Commercial Grade (SO-8) Industrial Grade (SO-8) ● ● 1.195 1.190 1.188 No Load (MSOP) Commercial Grade (MSOP) Industrial Grade (MSOP) ● ● No Load (DFN) Commercial Grade (DFN) Industrial Grade (DFN) ● ● MAX UNITS 0.25 0.30 0.35 mV/V mV/V mV/V 25 12 µs µs VCC – 0.2 V VSS + 0.3 V 1.200 1.205 1.210 1.212 V V V 1.190 1.185 1.183 1.200 1.210 1.215 1.217 V V V 1.185 1.180 1.178 1.200 1.215 1.220 1.222 V V V 2 0.2 6 1.5 5 Reference (LTC1541 Only) VREF ∆VREF Reference Voltage Load Regulation ISOURCE = 1mA ISINK = 10µA ● ● en 16 mV mV mV Voltage Noise 0.1Hz to 10Hz Input Offset Voltage VCM = 1.5V (SO-8) Commercial Grade (SO-8) Industrial Grade (SO-8) ● ● 0.7 1.25 1.65 mV mV mV VCM = 1.5V (MSOP) Commercial Grade (MSOP) (DFN) Industrial Grade (MSOP) (DFN) ● ● 1.00 1.75 2.0 mV mV mV ● 1 nA µVP-P Op Amp VOS IB Input Bias Current VCM = 1.5V AVOL Large-Signal Gain AMPOUT = 0.5V to 2.5V, No Load AMPOUT = 0.5V to 2.5V, RLOAD = 100k Commercial Grade Industrial Grade ● ● 0.01 80.0 45.5 22.0 20.0 1000 500 V/mV V/mV V/mV V/mV GBW Gain Bandwidth AV = 1V/V 12 kHz SR Slew Rate AV = 1V/V 8 V/ms VCM Input Common Mode Range CMRR Common Mode Rejection Ratio PSRR VOH VOL Power Supply Rejection Ratio Output High Voltage Output Low Voltage ● VSS VCC – 1.3 V VCM = VSS to (VCC – 1.3V) Commercial Grade Industrial Grade ● ● 0.7 0.8 0.8 mV/V mV/V mV/V VCC = 3V to 12V Commercial Grade Industrial Grade ● ● 0.19 0.21 0.23 mV/V mV/V mV/V RLOAD = 100k to VSS Commercial Grade Industrial Grade ● ● RLOAD = 100k to VCC Commercial Grade Industrial Grade ● ● VCC – 0.07 VCC – 0.10 VCC – 0.12 V V V VCC + 0.05 VCC + 0.10 VCC + 0.12 V V V 15412fd 5 LTC1541/LTC1542 ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 3V, VSS = 0V, unless otherwise noted. SYMBOL PARAMETER ISOURCE Output Source Current ISINK CONDITIONS MIN TYP 0.95 ● 0.6 0.4 mA mA 1.2 0.8 1.8 ● mA mA Output Sink Current en Input Noise Voltage fO = 0.1Hz to 10Hz MAX UNITS 3 Note 1: Absolute Maximum Ratings are those values beyond which the life of the device may be impaired. Note 2: Supply current is tested with COMPIN+ = (REF – 100mV) for LTC1541 and COMPIN+ = 0V, COMPIN– = 100mV for LTC1542. Note 3: Input offset voltage is defined as the center of the input referred hysteresis, VCM = REF (LTC1541). VCM = 1/2 VCC (LTC1542). Note 4: Trip point is defined as the differential input voltage required to make the comparator output change state. The difference between upper and lower trip point is equal to the width of the input referred hysteresis, VCM = REF (LTC1541). VCM = 1/2 VCC (LTC1542). Note 5: The input leakage current is measured for COMPIN+ at 0V (LTC1541) and COMPIN+ = COMPIN– = 0V (LTC1542). µVP-P Note 6: The θJA specified for the DD package is with minimal PCB heat spreading metal. Using expanded metal area on all layers of a board reduces this value. Note 7: The LTC1541C/LTC1541I and LTC1542C/LTC1542I are guaranteed functional over the operating temperature range of –40°C to 85°C. Note 8: The LTC1541C and LTC1542C are guaranteed to meet specified performance from 0°C to 70°C. The LTC1541C and LTC1542C are designed, characterized and expected to meet performance from –40°C to 85°C, but are not tested or QA sampled at these temperatures. The LTC1541I and LTC1542I are guaranteed to meet specified performance from –40°C to 85°C. U W TYPICAL PERFOR A CE CHARACTERISTICS 1.205 10 NONINVERTING VSS = GND AMPIN+ = VCC /2 8 9 SUPPLY CURRENT (µA) 9 7 6 5 4 3 2 8 VCC = 5V VSS = GND AMPIN – = AMPOUT AMPIN + = 2.5V REFERENCE OUTPUT VOLTAGE (V) 10 SUPPLY CURRENT (µA) Reference Output Voltage vs Load Current Supply Current vs Temperature Supply Current vs Supply Voltage 7 6 5 4 3 1 0 2 3 4 5 6 7 8 9 10 11 12 SUPPLY VOLTAGE (V) 1541/42 TPC01 2 –50 VCC = 5V VSS = GND 1.204 1.203 SOURCING CURRENT 1.202 1.201 1.200 1.199 1.198 SINKING CURRENT 1.197 1.196 1.195 –25 0 25 50 75 TEMPERATURE (°C) 100 125 1541/42 TPC02 1 100 1000 10 LOAD CURRENT (µA) 10000 1541/42 TPC03 15412fd 6 LTC1541/LTC1542 U W TYPICAL PERFOR A CE CHARACTERISTICS Reference Output Voltage vs Temperature 1x106 1.202 VCC = 5V VSS = GND 1.199 1.198 1.197 1.196 –25 0 25 50 75 TEMPERATURE (°C) 100 1x105 VSUPPLY = ±1.5V 1x10 4 1x103 VCC = 5V VSS = GND RLOAD = 100kΩ 1x102 1x10 125 0.6 OUTPUT VOLTAGE (mV) 1.200 1.195 –50 1 0.8 DC OPEN-LOOP GAIN (V/V) REFERENCE OUTPUT (V) 1.201 0.4 0 SOURCING CURRENT –0.2 –0.6 –0.8 VSUPPLY = ±1.5V –1 –50 –25 0 25 50 75 TEMPERATURE (°C) 100 1 125 Op Amp DC Open-Loop Gain vs Supply Voltage 5 0 –2 SHORT TO VCC –4 NONINVERTING VSS = GND AMPIN+ = VCC /2 –6 –8 1000 100 10 2 3 4 5 6 7 8 9 10 11 12 SUPPLY VOLTAGE (V) VCC = 5V VSS = GND SOURCING CURRENT 3 2 SINKING CURRENT 1 1 0.1 –10 4 OUTPUT VOLTAGE (V) 2 DC OPEN-LOOP GAIN (V/mV) 8 4 2 3 4 5 6 7 8 9 10 11 12 SUPPLY VOLTAGE (V) 0 0.01 0.1 1 10 100 LOAD CURRENT (mA) 1541/42 TPC08 1000 1541/42 TPC09 1541/42 TPC07 Comparator Short-Circuit Current vs Supply Voltage 10000 Comparator Output Voltage vs Load Current RLOAD = 100kΩ SHORT TO VSS 100 1000 10 LOAD CURRENT (µA) 1541/42 TPC06 10,000 6 VSUPPLY = ±2.5V –0.4 1541/42 TPC05 Op Amp Short-Circuit Current vs Supply Voltage 10 VSUPPLY = ±2.5V SINKING CURRENT 0.2 1 1541/42 TPC04 OUTPUT CURRENT (mA) Op Amp Output Voltage vs Load Current Op Amp DC Open-Loop Gain vs Temperature Op Amp Small-Signal Transient Response Op Amp Large-Signal Transient Response 250 SHORT-CIRCUIT CURRENT (mA) 200 150 SHORT TO VSS INPUT 200mV/DIV INPUT 2V/DIV OUTPUT 100mV/DIV OUTPUT 1V/DIV 100 50 0 –50 –100 SHORT TO VCC –150 –200 –250 2 3 4 5 6 7 8 9 10 11 12 SUPPLY VOLTAGE (V) NONINVERTING AVCL = 1V/V LOAD = 100kΩ//100pF TO VSS VSUPPLY = 5V 1541/42 TPC11 NONINVERTING AVCL = 1V/V LOAD = 100kΩ//100pF TO VSS VSUPPLY = 5V 1541/42 TPC11 1541/42 TPC10 15412fd 7 LTC1541/LTC1542 U W TYPICAL PERFOR A CE CHARACTERISTICS 120 0 100 –45 –90 80 PHASE –135 60 –180 40 GAIN –225 20 0 –20 –40 –270 VCC = 5V VSS = GND RLOAD = 100kΩ 10 100 PHASE SHIFT (DEGREES) OPEN-LOOP GAIN (dB) Op Amp Open-Loop Gain and Phase vs Frequency –315 1k 10k FREQUENCY (Hz) 100k –360 1M 1541/42 TPC13 U U U PI FU CTIO S AMPOUT (Pin 1): Op Amp Output. The output can swing from rail-to-rail while driving a capacitive load of up to 1000pF. The output can source and sink 0.7mA (min). AMPIN– (Pin 2): Inverting Input of Op Amp. The input common mode ranges from VSS to (VCC – 1.3V). The input current is typically 10pA at 25°C. REF (Pin 6) (LTC1541): Reference Output. VREF = 1.2V ±1% over industrial temperature range, and is also connected to inverting comparator input internally. This device can source up to 2mA and sink up to 20µA. The output can drive a bypass capacitor of up to 0.01µF without oscillation. AMPIN+ (Pin 3): Noninverting Input of Op Amp. The input common mode ranges from VSS to (VCC – 1.3V). The input current is typically 10pA at 25°C. COMPIN – (Pin 6) (LTC1542): Inverting Input of Comparator. The input common mode ranges from VSS to (VCC – 1.3V). The input current is typically 10pA at 25°C. VSS (Pin 4): Negative Supply or Ground Connection. COMPOUT (Pin 7): Comparator Output. The output can source 20mA and sink 5mA. COMPIN+ (Pin 5): Noninverting Input of Comparator. The input common mode ranges from VSS to (VCC – 1.3V). The input current is typically 10pA at 25°C. VCC (Pin 8): Positive Supply, 2.5V ≤ VCC ≤ 12.6V. The supply bypass capacitors are not required if the supply impedance is low. For single supply applications, it is a good general practice to bypass VCC with a 0.1µF capacitor to ground. W BLOCK DIAGRA S LTC1541 LTC1542 VCC + 1 AMPOUT COMPOUT OP AMP 8 7 + 1 AMPOUT – 8 COMPOUT 7 COMPIN – 6 COMPIN + 5 – 2 AMPIN – ×1 3 AMPIN + COMP 4 VSS OP AMP VCC REF 6 2 AMPIN – – + 3 AMPIN + COMPIN + LTC1541 BD 5 4 VSS COMP – + LTC1541 BD2 15412fd 8 LTC1541/LTC1542 U W U U APPLICATIO S I FOR ATIO The LTC1541/LTC1542 are a combination of a micropower op amp, comparator and 1.2V ±1% reference (LTC1541) in an 8-pin package. The LTC1541 has the negative input of the comparator internally connected to the reference output. The supply voltage range is from 2.5V to 12.6V for single supply and ±1.25V to ±6.3V for dual supplies. The supply current is a mere 5µA (typical) with a 5V single supply. Op Amp The op amp is internally compensated to be unity-gain stable, with typical GBW at 12kHz and slew rate of 8V/ms. The output can drive a capacitive load of up to 1000pF and swings from rail-to-rail. The input range is from the negative rail to within 1.3V of the positive rail. The input bias current is less than 1nA maximum at the extended temperature range. 8 LTC1541 VCC 6 REF ×1 R1 C1 VSS 4 1541/42 F01 Figure 1. Damping the Reference Output Comparator The comparator has a high impedance differential input stage with a common mode input range from the negative rail to within 1.3V of the positive rail. The CMOS output stage can swing from rail-to-rail and source up to 20mA continuously. The output stage has been designed to eliminate the power supply glitches that normally occur when the output changes logic state. In addition, internal hysteresis (±2.25mV) ensures clean output switching even with slow moving input signals. The negative input is internally connected to the reference for the LTC1541. Reference The internal bandgap reference has an output voltage of 1.2V ±1% over the industrial grade temperature range. The output can source up to 2mA and sink up to 20µA with a 5V supply. The output can drive a bypass capacitor of up to 0.01µF without oscillation and by inserting a series resistor, capacitance values up to 100µF can be used (Figure 1). Figure 2 shows the resistor value required for different capacitor values to achieve critical damping. Bypassing the reference can help prevent false tripping of the comparator by preventing glitches on VCC or reference load transients from disturbing the reference output voltage. Figures 3a and 3b show the bypass reference output with a square wave applied to the VCC pin while resistor R1 damps the reference response. Note that the comparator output doesn’t trip. Op Amp Stability Unlike other industry standard micropower CMOS op amps, the op amp in the LTC1541/LTC1542 maintain stability in unity-gain configuration while driving heavy capacitive loads of up to 1000pF. Although this family is primarily designed for low frequency applications, good layout is extremely important. Low power, high impedance circuits may increase the effects of board leakage and stray capacitance. For example, the combination of a 10M resistance (from leakage between traces on a contaminated, poorly designed PC board) and a 1pF stray capacitance provides a pole at approximately 16kHz, which is near the amplifier’s bandwidth. Board routing and layout should minimize leakage and stray capacitance. In some cases, stray capacitance may be unavoidable and it may be necessary to add a small capacitor across the feedback resistor to compensate (Figure 4); select the smallest capacitor value that ensures stability. Inputs The input common mode range for both the op amp and comparator is from the negative supply to within 1.3V of the positive supply. The inputs can be taken more than 300mV below the negative supply without damaging the device if the current out of the pin is limited to less than 1mA. Unlike bipolar input op amps and comparators, the outputs of the CMOS LTC1541/LTC1542 will not reverse phase when the inputs are taken above the common mode input range. 15412fd 9 LTC1541/LTC1542 U W U U APPLICATIO S I FOR ATIO RESISTOR VALUE (kΩ) 1000 LTC1541 8 VCC 100 7 COMPOUT 5V TO 8V 6 REF ×1 10 R1 430Ω – 1 0.1 0.001 0.01 0.1 1 CAPACITOR VALUE (µF) C1 1µF 10 5 COMP COMPIN + + VSS 4 1541/42 F02 Figure 2. Damping Resistance vs Bypass Capacitor Value 1541/42 F03a Figure 3a. Reference Transient Response Test Circuit 8V V+ AMPIN + 2mV/DIV 5V + OP AMP VREF AMPOUT – R2 OUT R1 2ms/DIV 2pF TO 10pF LTC1541 • F03b 1541/42 F04 Figure 4. Compensation for Feedback Node Capacitance Figure 3b. Reference and Comparator Output Transient Response U TYPICAL APPLICATIO S Shunt Battery Charger with Low-Battery Load Disconnect Si9405 2A FUSE 6.8V ZENER 1N754 3.65M 1A SOLAR ARRAY 3 + 1/2 LTC1541 2 340k – TIP121 8 1 7.5Ω 10W DALE HLM-10 1M 8M 1M 5 12V 5AHR GEL CELL 6 4 + 1/2 LTC1541 7 LOAD VN2222 – 1M VREF = 1.2V (INTERNAL) 1541/42 TA06 15412fd 10 LTC1541/LTC1542 U PACKAGE DESCRIPTIO DD Package 8-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1698) R = 0.115 TYP 5 0.38 ± 0.10 8 0.675 ±0.05 1.65 ± 0.10 (2 SIDES) 3.00 ±0.10 (4 SIDES) 3.5 ±0.05 1.65 ±0.05 2.15 ±0.05 (2 SIDES) PACKAGE OUTLINE PIN 1 TOP MARK (DD8) DFN 0203 0.28 ± 0.05 4 0.28 ± 0.05 0.75 ±0.05 0.200 REF 1 0.50 BSC 0.50 BSC 2.38 ±0.05 (2 SIDES) 2.38 ±0.10 (2 SIDES) 0.00 – 0.05 BOTTOM VIEW—EXPOSED PAD NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1) 2. ALL DIMENSIONS ARE IN MILLIMETERS 3. 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 4. EXPOSED PAD SHALL BE SOLDER PLATED RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS MS8 Package 8-Lead Plastic MSOP (Reference LTC DWG # 05-08-1660) 0.889 ± 0.127 (.035 ± .005) 0.254 (.010) DETAIL “A” 3.00 ± 0.102 (.118 ± .004) (NOTE 3) 0° – 6° TYP 8 GAUGE PLANE 5.23 (.206) MIN 0.53 ± 0.152 (.021 ± .006) 3.20 – 3.45 (.126 – .136) 0.52 (.0205) REF 3.00 ± 0.102 (.118 ± .004) (NOTE 4) 4.90 ± 0.152 (.193 ± .006) DETAIL “A” 0.42 ± 0.038 (.0165 ± .0015) TYP 7 6 5 0.18 (.007) 0.65 (.0256) BSC 1 2 3 4 1.10 (.043) MAX RECOMMENDED SOLDER PAD LAYOUT NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX SEATING PLANE 0.22 – 0.38 (.009 – .015) TYP 0.86 (.034) REF 0.127 ± 0.076 (.005 ± .003) 0.65 (.0256) BSC MSOP (MS8) 0204 S8 Package 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610) .189 – .197 (4.801 – 5.004) NOTE 3 .045 ±.005 .050 BSC .010 – .020 × 45° (0.254 – 0.508) .008 – .010 (0.203 – 0.254) .245 MIN .053 – .069 (1.346 – 1.752) 0°– 8° TYP 8 7 6 5 .004 – .010 (0.101 – 0.254) .160 ±.005 .016 – .050 (0.406 – 1.270) .030 ±.005 TYP RECOMMENDED SOLDER PAD LAYOUT NOTE: 1. DIMENSIONS IN .014 – .019 (0.355 – 0.483) TYP INCHES (MILLIMETERS) 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) .050 (1.270) BSC .150 – .157 (3.810 – 3.988) NOTE 3 .228 – .244 (5.791 – 6.197) 1 2 3 4 SO8 0303 15412fd 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. 11 LTC1541/LTC1542 U TYPICAL APPLICATIO S Single Supply Function Generator Negative Reference VCC 3V TO 12V VCC 3V TO 9V 0.1µF 5M 200k 2 2 3 – 8 LTC1542 OP AMP + 5M LT1634-2.5 1 3 VOUT –2.5V – 8 1 LTC1542 OP AMP + 4 R2 500k R1 10M 6 – 5 + LTC1542 COMP 4 R3 5M 7 FREQ ≈ R1 4C • R2 • R3 1541/42 TA04 VSS –3V 1541/42 TA05 Voltage Control Oscillator R1 300k C1 0.047µF 2 1M VIN 0V – VCC 3 R2 150k VCC – 8 + R4 5M 1 LTC1542 OP AMP 4 – LTC1542 COMP 5 1M VC 2.4C • R1 • VCC VALUES SHOWN ARE FOR 100Hz WITH VIN = VCC 6 7 5V 0V VOUT + FREQ ≈ R4 1.1M VN2222 R3 500k VN2222 1541/42 TA03 Linear Lithium-Ion Charger D1 1N5817 Q1 FZT2907A VIN 6V 300mA IC1 C3 0.01µF R1 220Ω LTC1541 0.25W VCC 8 ×1 Q2 2N3906 1 2 R1 1M 3 SHUTDOWN 7 – 300mA 4.2V FLOAT Li-ION 5 + C2 0.1µF 4 VSS R3 3.83k 1% R5 2.2M 6 – + R8 249k 0.5% R4 100k 1% C1 4700pF R7 0.15Ω R6 33k R9 100k 0.5% 1541/42 TA07 RELATED PARTS PART NUMBER LT® 1078/LT1079 LT1178/LT1179 LT1490/LT1491 LT1635 LT2078/LT2079 LT2178/LT2179 DESCRIPTION Dual/Quad Micropower, Single Supply Precision Op Amps COMMENTS 70µV, VOS Max and 0.4µV/°C Drift, 200kHz GBW, 0.07V/µs Slew Rate, Input/Output Common Mode Includes Ground Dual/Quad 17µA Max, Single Supply Precision Op Amps 70µV, VOS Max and 2.5µV/°C Drift Max, 85kHz GBW, 0.04V/µs Slew Rate, Input/Output Common Mode Includes Ground Dual/Quad Micropower Rail-to-Rail Input and Output Op Amps Single Supply Input Range: – 0.4V to 44V, Micropower 50µA Amplifier, Rail-to-Rail Input and Output, 200kHz GBW Micropower Rail-to-Rail Op Amp and Reference 130µA of Supply Current, 1.3mV VOS Max Dual/Quad Micropower, Single Supply Precision Op Amps SO-8 and 14-Lead Standard Pinout, 70µV VOS Max, 200kHz GBW Dual/Quad 17µA Max, Single Supply Precision Op Amps SO-8 and 14-Lead Standard Pinout, 70µV VOS Max, 85kHz GBW 15412fd 12 Linear Technology Corporation LT 1105 REV D • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2005