Sc561 Dual Output Low Noise Ldo Linear Regulator Power Management

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SC561 Dual Output Low Noise LDO Linear Regulator POWER MANAGEMENT Features Description „ The SC561 is a dual output, ultra-low dropout linear voltage regulator designed for use in battery powered applications. The SC561 provides fixed output voltages of VLDOA = 3.1V and VLDOB = 2.85V, and up to 300mA of load current per channel. „ „ „ „ „ „ „ „ „ „ „ „ Input voltage range — 2.5V to 5.5V Output voltage — VLDOA = 3.1V; VLDOB = 2.85V Maximum output current — 300mA (each LDO) Dropout at 200mA load — 200mV max. Quiescent supply current — 40μA (both LDOs enabled) Shutdown current — 100nA (typ) Output noise < 50μVRMS PSRR >65dB at 1kHz Over-temperature protection Short-circuit protection Under-voltage lockout Power good monitor for output A MLPQ-UT8, 1.5mm x 1.5mm x 0.6mm package In applications where maximum battery life is essential, the SC561 can operate in an extremely low power state by setting the dynamic bias control. At very light loads, the LOAD pin can be pulled low so that the device consumes only 40μA of quiescent current. The SC561 provides superior low-noise performance by using an external bypass capacitor to filter the bandgap reference. The device also has a PGOOD output to hold a processor in reset when the voltage on OUTA is not in regulation. Applications „ „ „ „ „ „ „ „ PDAs and cellular phones GPS devices Palmtop computers and handheld instruments TFT/LCD applications Wireless handsets Digital cordless phones and PCS phones Personal communicators Wireless LAN The device provides protection circuitry such as shortcircuit protection, under-voltage lockout, and thermal protection to prevent device failures. Stability is maintained by using 1μF capacitors on the output pins. The MLPQ-UT8 package and small ceramic bypass capacitors minimize the required PCB area. Typical Application Circuit SC561 PGOOD VIN IN EN EN OUTA OUTA LOAD OUTB OUTB LOAD CIN 2.2μF November 21, 2007 PGOOD GND BYP CBYP 22nF COUTA 1μF COUTB 1μF 1 SC561 Pin Configuration Ordering Information Device Package SC561ULTRT(1)(2) MLPQ-UT8 1.5×1.5 SC561EVB Evaluation Board PGOOD 8 OUTB 1 7 BYP 6 EN 5 GND TOP VIEW IN 2 OUTA 3 4 Notes: (1) Available in tape and reel only. A reel contains 3,000 devices. (2) Lead-free package only. Device is WEEE and RoHS compliant. LOAD MLPQ-UT-8; 1.5x1.5, 8 LEAD θJA = 157°C/W Marking Information Voltage Options Device SC561 Output Voltage Options VLDOA VLDOB Part Number Code 3.1 2.85 0V nn yw nn = Part No. Code — See the Voltage Options Table for details yw = Datecode — See package marking design guidelines document #ALOW-693AQX 2 SC561 Absolute Maximum Ratings Recommended Operating Conditions IN (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +6.5 Ambient Temperature Range (°C) . . . . . . . . . -40 < TA < +85 EN, LOAD(V) . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to (VIN + 0.3) VIN (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 to 5.5 PGOOD (V) . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to (VIN + 0.3) Pin Voltage — All Other Pins (V) . . . . . . . . . -0.3 to (VIN + 0.3) OUTA, OUTB, Short Circuit Duration . . . . . . . . Continuous ESD Protection Level(1) (kV) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Thermal Information Thermal Resistance, Junction to Ambient(2) (°C/W) . . . 157 Maximum Junction Temperature (°C) . . . . . . . . . . . . . . +150 Storage Temperature Range (°C) . . . . . . . . . . . . -65 to +150 Peak IR Reflow Temperature (10s to 30s) (°C) . . . . . . . +260 Exceeding the above specifications may result in permanent damage to the device or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not recommended. NOTES: (1) Tested according to JEDEC standard JESD22-A114-B. (2) Calculated from package in still air, mounted to 3 x 4.5 (in), 4 layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards. Electrical Characteristics Unless otherwise noted VIN = 3.6V, CIN = 2.2μF, COUTA = COUTB = 1μF, VEN = VLOAD = VIN, TA = -40 to +85°C. Typical values are at TA = 25°C. All specifications apply to both LDOs unless otherwise noted. Parameter Input Supply Voltage Range Symbol Conditions VIN Min Typ 2.5 VOUTA 3.1 VOUTB 2.85 Max Units 5.5 V Output Voltage V Output Voltage Accuracy ΔVOUTx VIN = 2.5V to 5.5V, IOUTx = 0 to 300mA, VIN ≥ VOUTx + 0.3 -3 Maximum Output Current IMAX Each LDO 300 Dropout Voltage(1) VD Shutdown Current ISD Quiescent Current IQ 3 % mA IOUTx = 250mA, VOUTx = 2.5V to 3.3V 150 250 mV IOUTx = 50mA, VOUTx = 2.5V to 3.3V 50 100 mV TA = 25°C 0.1 1 μA IOUTA = IOUTB = 0mA, LOAD = VIN 55 85 μA IOUTA = IOUTB = 1mA, LOAD = 0V 40 60 μA 20 mV 6 mV Load Regulation ΔVLOAD IOUTx = 1mA to IMAX Line Regulation ΔVLINE IOUTx = 1mA -6 3 SC561 Electrical Characteristics (continued) Parameter Symbol Current Limit ILIMx Noise eN IOUTx = 50mA , 10Hz < f < 100kHz, CBYP = 22nF Power Supply Rejection Ratio PSRR IOUTx = 50mA, f = 1kHz, CBYP = 22nF PGOOD Delay tDELAY PGOOD Threshold V TH-PGOOD PGOOD Threshold Hysteresis VPGOOD-HYS Start-Up Time Under Voltage Lockout UVLO Hysteresis Conditions Min 350 50 From OFF to 87% VOUTx, IOUTx = 50mA, CBYP = 22nF VUVLO VIN Rising Over Temperature Threshold Hysteresis VOT-HYS Units 850 mA 100(2) μVRMS 65 160 200 240 ms 82 87 92 % 2.20 VUVLO-HYS TOT Max 50(2) Percentage of nominal output, VOUTA falling tSU Over Temperature Protection Threshold(3) Typ Temperature Rising dB 3 % 1 ms 2.30 2.40 V 100 mV 160 °C 20 °C Digital Inputs Logic Input High Threshold VIH VIN = 5.5V Logic Input Low Threshold VIL VIN = 2.5V 0.4 V Logic Input High Current IIH VIN = 5.5V 1 μA Logic Input Low Current IIL VIN = 5.5V 1 μA VOL ISINK = 500μA,VIN=3.7V 20 mV 1.25 V Digital Outputs PGOOD Output voltage Low 7 Notes: (1) Dropout voltage is defined as VIN - VOUTx , when VOUTx is 100mV below the value of VOUTx at VIN = VOUTx + 0.5V. (2) Guaranteed by design (3) Thermal shutdown latches both LDOs off. Cycle EN or VIN pin to reset. 4 SC561 Typical Characteristics Load Regulation (LDOA) Load Regulation (LDOB) VOUTA = 3.1V, VIN = 3.6V 8 7 7 Output Voltage Variation (mV) Output Voltage Variation (mV) VOUTB = 2.85V, VIN = 3.6V 8 6 5 TA=85°C 4 TA=25°C 3 2 1 6 5 4 TA=25°C TA=85°C 3 2 1 TA=-40°C TA=-40°C 0 0 0 50 100 150 200 Output Current (mA) 250 0 300 50 100 150 200 Output Current (mA) Line Regulation (LDOA) 3 VOUTA = 3.1V, IOUTA = 1mA 2.5 Output Voltage Variation (mV) Output Voltage Variation (mV) VOUTB = 2.85V, IOUTB = 1mA 3 2 1.5 1 TA=25°C 0.5 TA=85°C 2 1.5 1 TA=85°C TA=25°C 0.5 TA=-40°C 0 0 -0.5 2.9 TA=-40°C 3.1 3.3 3.5 3.7 3.9 4.1 4.3 4.5 Input Voltage (V) 4.7 4.9 5.1 -0.5 5.3 2.7 2.9 3.1 5.5 3.3 VOUTA = 3.1V, IOUTA = 250mA 350 300 250 250 VIN - VOUT (mV) 300 TA=85°C 200 150 100 TA=25°C TA=-40°C 3.7 3.9 4.1 4.3 4.5 Input Voltage (V) 4.7 4.9 5.1 5.3 5.5 VOUTB = 2.85V, IOUTB = 250mA TA=85°C 200 TA=25°C 150 TA=-40°C 100 50 50 0 3.1 3.5 Dropout Voltage (LDOB) Dropout Voltage (LDOA) VIN - VOUT (mV) 300 Line Regulation (LDOB) 2.5 350 250 0 3.15 3.2 3.25 3.3 Input Voltage (V) 3.35 3.4 2.8 2.85 2.9 2.95 Input Voltage (V) 3 3.05 3.1 5 SC561 Typical Characteristics (continued) Dropout Voltage (LDOA) 350 Dropout Voltage (LDOB) VOUTA = 3.1V, IOUTA = 50mA VOUTB = 2.85V, IOUTB = 50mA 300 300 250 VIN - VOUT (mV) VIN - VOUT (mV) 250 200 TA=-40°C 150 TA=85°C 100 200 150 TA=85°C 100 TA=-40°C TA=25°C 50 50 0 3.1 TA=25°C 3.15 3.25 3.3 Input Voltage (V) 3.2 3.35 0 2.8 3.4 PSRR vs. Frequency (LDOA) -10 -20 -20 -30 -30 -40 -50 -70 -70 -80 10 10000 Frequency (Hz) Output Noise vs. Load Current (LDOA) VOUTA = 3.1V, VIN = 3.6V, CBYP = 22nF Output Voltage Noise (μV) 60 70 TA=85°C TA=-40°C 40 100 Frequency (Hz) 1000 10000 VOUTB = 2.85V, VIN = 3.6V, CBYP = 22nF 60 TA=25°C 50 3.1 Output Noise vs. Load Current (LDOB) Output Voltage Noise (uV) 70 3.05 -50 -60 1000 3 -40 -60 100 2.95 Input Voltage (V) VOUTB = 2.85V, IOUTB = 50mA, CBYP = 22nF 0 -10 -80 10 2.9 PSRR vs. Frequency (LDOB) VOUTA = 3.1V, IOUTA = 50mA, CBYP = 22nF PSRR (dB) PSRR (dB) 0 2.85 30 20 10 50 TA=85°C 40 TA=25°C 30 TA=-40°C 20 10 0 0 1 10 100 Output Current (mA) 1000 1 10 100 Output Current (mA) 1000 6 SC561 Typical Characteristics (continued) Load Transient Response Rising Edge (Both LDOs) Load Transient Response Falling Edge (Both LDOs) VIN = 3.6V, VOUT = 3.1V, LOAD = H VIN = 3.6V, VOUT = 3.1V, LOAD = H IOUT=1mA to 100mA IOUT=1mA to (50mA/div) 100mA (50mA/div) VOUT VOUT (20mV/div) (20mV/div) Time (50μs/div) Load Transient Response Rising Edge (Both LDOs) Time (50μs/div) Load Transient Response Falling Edge (Both LDOs) VIN = 3.6V, VOUT = 3.1V, LOAD = H VIN = 3.6V, VOUT = 3.1V, LOAD = H IOUT=1mA to IOUT=1mA to 3mA 3mA (50mA/div) (50mA/div) VOUT VOUT (10mV/div) (10mV/div) Time (50μs/div) Load Transient Response Rising Edge (Both LDOs) Time (50μs/div) Load Transient Response Falling Edge (Both LDOs) VIN = 3.6V, VOUT = 3.1V, LOAD = L VIN = 3.6V, VOUT = 3.1V, LOAD = L IOUT=1mA to IOUT=1mA to 3mA 3mA (50mA/div) (50mA/div) VOUT VOUT (10mV/div) (10mV/div) Time (50μs/div) Time (50μs/div) 7 SC561 Pin Configurations and Descriptions SC561 Pin Name Pin Function 1 OUTB Output for LDOB 2 VIN 3 OUTA Output for LDOA 4 LOAD Dynamic bias control — pull this pin high for normal operation at all load currents. Pull this pin low for lowest IQ at loads less than 2mA. This pin is a logic input and cannot be left unconnected. 5 GND Analog and digital ground 6 EN Logic input — active HIGH enables both LDOs 7 BYP LDO bypass output — bypass with a 22nF capacitor 8 PGOOD Input supply voltage terminal Power Good open-drain output — monitors the level of LDOA, switches low when the output drops out of regulation. Tie to VIN or OUTA via a 100k Ω resistor. Leave floating when function is not required. 8 SC561 Block Diagram SC561 VIN VIN 2 VREF 7 BYP 8 PGOOD 3 OUTA 1 OUTB PGOOD Logic UVLO VIN GND EN LOAD 5 6 O/T PowerON Logic LDOA VIN LDOB 4 9 SC561 Applications Information General Description Dynamic Bias Control The SC561 is a dual output linear regulator device intended for applications where low dropout voltage, low supply current, and low output noise are critical. The device provides a simple, low cost solution for two separate regulated outputs. Minimal PCB area is required due to the miniature package size and the need for only four external capacitors. The LOAD pin provides dynamic bias control which allows the device to be operated in a low quiescent current mode at light loads. At loads less than 2mA, the LOAD pin should be pulled low in order to force the device into an ultra-low quiescent current mode. When the load is increased above 2mA, the LOAD pin should be pulled high to ensure normal operation. This pin is a logic input, therefore it must never be left unconnected. Figure 2 shows the quiescent current versus load current with both LDOs enabled. The linear regulators LDOA and LDOB are powered from a single input supply rail, and each provides up to 300mA of output current. The SC561 provides output voltages in the range 1.2V to 3.3V. Available voltage values are shown in the Voltage Options table on page 2. 1.4 1.2 1 The SC561 device has a single enable pin (EN) that controls both LDO outputs. Pulling this pin low causes the device to enter a low power shutdown mode where it typically draws 100nA from the input supply. The outputs of both LDOA and LDOB are enabled when EN transitions high. When the output voltage of LDOA reaches 87% of its regulation point, the delay timer starts and the PGOOD signal transitions high after a delay of 200ms. The power up/down sequence is shown in the timing diagram in Figure 1. Iq (mA) Power On Control 0.8 0.6 0.4 0.2 LOAD = H 0 0.01 0.1 1 10 100 1000 Io (mA) Figure 2a - Quiescent Current versus Output Current 0.2 0.18 0.16 EN 0.14 tSU 87% 200ms PGOOD 0.12 Iq (mA) 87% OUTA 0.1 0.08 0.06 0.04 LOAD = L 0.02 OUTB Figure 1 — Timing Diagram 0 0.01 0.1 1 Io (mA) As PGOOD is an open-drain output, it can be left unconnected when it is not in use without affecting the performance of the device. 10 100 1000 Figure 2b - Quiescent Current versus Output Current 10 SC561 Applications Information (continued) Protection Features The SC561 provides protection features to ensure that no damage is incurred in the event of a fault condition. These functions include: • • • Under-Voltage Lockout Over-Temperature Protection Short-Circuit Protection Under-Voltage Lockout The Under-Voltage Lockout (UVLO) circuit protects the device from operating in an unknown state if the input voltage supply is too low. When the VIN drops below the UVLO threshold, as defined in the Electrical Characteristics section, the LDOs are disabled and PGOOD is held low. The LDOs are re-enabled into their previous states when VIN is increased above the hysteresis level. When powering up with VIN below the UVLO threshold, the LDOs remain disabled and PGOOD is held low. Over-Temperature Protection An internal Over-Temperature (OT) protection circuit is provided that monitors the internal junction temperature. When the temperature exceeds the OT threshold as defined in the Electrical Characteristics section, the OT protection disables both LDO outputs and holds the PGOOD signal low. The LDOs can only be re-enabled by cycling the EN pin. Short-Circuit Protection Each output has short-circuit protection. If the output current exceeds the current limit, the output voltage will drop and the output current will be limited until the load current returns to a specified level. Component Selection A minimum capacitance of 1μF on each output is required to ensure stability. This must be considered when choosing very small size capacitors as the dc bias must be included in their derating to ensure this required value. For example, a 1μF 0402 size capacitor may work at low output voltages, but the capacitance may be too low at higher output voltages. Although there is no maximum value of output capacitor specified, very large values may increase the rise time of the output voltages without affecting stability. It is recommended that the value of output capacitance be restricted to a maximum of 10μF. Ceramic capacitors of type X5R or X7R should be used because of their low ESR and stable temperature coefficients. It is also recommended that the input be bypassed with a 2.2μF, low ESR X5R or X7R capacitor to minimize noise and improve transient response. Note: Tantalum and Y5V capacitors are not recommended. The BYP pin on the SC561 must have a minimum of 22nF connected to ground to meet all noise-sensitive requirements. This value can be increased to a maximum of 1μF to improve noise and PSRR. However, larger values of bypass capacitor will increase the start-up time of the SC561. 11 SC561 Applications Information (continued) Thermal Considerations Although each of the two LDOs in the SC561 can provide 300mA of output current, the maximum power dissipation in the device is restricted by the miniature package size. The graphs in Figures 3 and 4 can be used as a guideline to determine whether the input voltage, output voltages, output currents, and ambient temperature of the system result in power dissipation within the operating limits are met or if further thermal relief is required. 0.6 0.5 0.4 0.3 0.2 0.1 ______ TA=+25°C, PD(MAX)= 0.8W - - - - TA=+85°C, PD(MAX)= 0.41W 0 3 where TJ = Junction Temperature (°C) TA = Ambient Temperature (°C) 3.5 4 4.5 Input Voltage (V) θJA = Thermal Resistance Junction to Ambient (°C/W) 5 5.5 Example A SC561 is used to provide outputs of 3.1V, 150mA from LDOA and 2.85V, 250mA from LDOB. The input voltage is 4.2V, and the ambient temperature of the system is 40°C. PD= 0.15(4.2 – 3.1) + 0.25(4.2 – 2.85) = 0.503W 6 and Figure 3 — Safe Operating Limit TJ = 40 + (0.503 x 157) = 118.9°C 1.6 Figure 4 shows that the junction temperature would be within the maximum specification of 150°C for this power dissipation. This means that operation of the SC561 under these conditions is within the specified limits and the device would not require further thermal relief measures. 1.4 Maximum Power Dissipation (W) TJ = TA +(PD x θJA) PD = Power Dissipation (W) Maximum Recommended Input Voltage Maximum Total Output Current (A) 0.7 known operating conditions using the following equation: 1.2 1 TJ(Max)=150°C 0.8 0.6 TJ(Max)=125°C 0.4 0.2 0 -40 -20 0 60 20 40 Ambient Temperature (oC) 80 100 Figure 4 — Maximum PD vs. TA The following procedure can be followed to determine if the thermal design of the system is adequate. The junction temperature of the SC561 can be determined in 12 SC561 Applications Information (continued) Layout Considerations • While layout for linear devices is generally not as critical as for a switching application, careful attention to detail will ensure reliable operation. The diagram below illustrates proper layout of a circuit. • • Place the input, output, and bypass capacitors close to the device for optimal transient response and device behavior. Connect all ground connections directly to the ground plane whenever possible to minimize ground potential differences on the PCB. Attach the part to a large copper footprint, to enable better heat transfer from the device on PCBs where there are internal power and ground planes. COUTB SC561 CIN CBYP COUTA Layer 1 Scale = 20:1 (20mm = 1mm) Layer 2 Via between Layer 1 and Layer 2 13 SC561 Outline Drawing — MLPQ-UT8 D A B DIMENSIONS DIM PIN 1 INDICATOR (LASER MARK) A A1 A2 b D E e E L N aaa bbb INCHES MIN .020 .000 NOM - MILLIMETERS MAX .024 .002 (.006) .008 .010 .059 BSC .059 BSC .016 BSC 0.12 0.16 .014 8 .004 .004 .006 MIN 0.50 0.00 NOM - MAX 0.60 0.05 (0.1524) 0.20 0.25 1.50 BSC 1.50 BSC 0.40 BSC 0.30 0.40 0.35 8 0.10 0.10 0.15 A2 A SEATING aaa PLANE C C A1 LxN e 2 0.20 0.25 1 N bxN 0.17 bbb C A B NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 14 SC561 Land Pattern — MLPQ-UT8 Z DIMENSIONS G P 2X (C) (G) (Z) X R DIM INCHES MILLIMETERS C (.057) (1.45) G .028 0.70 P .016 0.40 R .004 0.10 X .008 0.20 Y .030 0.75 Z .087 2.20 Y NOTES: 1. CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). 2. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. Contact Information Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805) 498-2111 Fax: (805) 498-3804 www.semtech.com 15