TPS7A45xx www.ti.com ...................................................................................................................................................................................................... SLVS720 – JUNE 2008 LOW-NOISE, FAST-TRANSIENT-RESPONSE 1.5-A LDO VOLTAGE REGULATORS FEATURES 1 • • • • • • • • • • • • • • • • • 2 Optimized for Fast Transient Response Output Current: 1.5 A High Output Voltage Accuracy : 1% at 25°C Dropout Voltage: 300 mV Low Noise: 35 µVRMS (10 Hz to 100 kHz) High Ripple Rejection: 68 dB 1-mA Quiescent Current No Protection Diodes Needed Controlled Quiescent Current in Dropout Fixed Output Voltages: 1.5 V, 1.8 V, 2.5 V, 3.3 V Adjustable Output from 1.21 V to 20 V <1-µA Quiescent Current in Shutdown Stable with 10-µF Output Capacitor Stable with Ceramic Capacitors Reverse-Battery Protection No Reverse Current Thermal Limiting APPLICATIONS • • • • 3.3-V to 2.5-V Logic Power Supplies Post Regulator for Switching Supplies Wireless Infrastructure Radio-Frequency Systems DESCRIPTION The TPS7A45xx devices are low-dropout (LDO) regulators optimized for fast transient response. The device can supply 1.5 A of output current with a dropout voltage of 300 mV. Operating quiescent current is 1 mA, dropping to less than 1 µA in shutdown. Quiescent current is well controlled; it does not rise in dropout, as with many other regulators. In addition to fast transient response, the TPS7A45xx regulators have very low output noise, which makes them ideal for sensitive RF supply applications. Output voltage range is from 1.21 V to 20 V. The TPS7A45xx regulators are stable with output capacitors as low as 10 µF. Small ceramic capacitors can be used without the necessary addition of ESR, as is common with other regulators. Internal protection circuitry includes reverse-battery protection, current limiting, thermal limiting, and reverse-current protection. The devices are available in fixed output voltages of 1.5 V, 1.8 V, 2.5 V, 3.3 V, and as an adjustable device with a 1.21-V reference voltage. The TPS7A45xx regulators are available in the 5-pin TO-263 (KTT) package. KTT PACKAGE (TOP VIEW) 5 4 3 2 1 SENSE/ADJ OUT GND IN SHDN 1 2 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. PowerPAD, PowerFLEX are trademarks of Texas Instruments. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2008, Texas Instruments Incorporated TPS7A45xx SLVS720 – JUNE 2008 ...................................................................................................................................................................................................... www.ti.com This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. ORDERING INFORMATION (1) (2) PRODUCT TPS7A45xxyyyz (1) (2) VOUT xx is nominal output voltage 15 = 1.5 V (PREVIEW), 18 = 1.8 V (PREVIEW), 25 = 2.5 V (PREVIEW), 33 = 3.3 V (ACTIVE), 01 = adjustable (ACTIVE) yyy is package designator (KTT) z is package quantity (R = 500) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI web site at www.ti.com. Package drawings, thermal data, and symbolization are available at www.ti.com/packaging. ABSOLUTE MAXIMUM RATINGS (1) over operating virtual-junction temperature range (unless otherwise noted) Input voltage range, VIN IN –20 V to 20 V OUT –20 V to 20 V Input-to-output differential (2) –20 V to 20 V SENSE –20 V to 20 V ADJ –7 V to 7 V SHDN –20 V to 20 V Output short-circuit duration, tshort Indefinite Maximum lead temperature (10-s soldering time), Tlead 300°C Operating virtual junction temperature range, TJ –40°C to 125°C Storage temperature range, Tstg –65°C to 150°C (1) (2) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. Absolute maximum input-to-output differential voltage cannot be achieved with all combinations of rated IN pin and OUT pin voltages. With the IN pin at 20 V, the OUT pin may not be pulled below 0 V. The total measured voltage from IN to OUT can not exceed ±20 V. PACKAGE THERMAL DATA (1) (1) (2) 2 PACKAGE BOARD θJA θJC θJP (2) TO-263 (KTT) High K, JESD 51-5 26.5°C/W 31.8°C/W 0.38°C/W Maximum power dissipation is a function of TJ(max), θJA, and TA. The maximum allowable power dissipation at any allowable ambient temperature is PD = (TJ(max) – TA)/θJA. Operating at the absolute maximum TJ of 150°C can affect reliability. For packages with exposed thermal pads, such as QFN, PowerPAD™, and PowerFLEX™, θJP is defined as the thermal resistance between the die junction and the bottom of the exposed pad. Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TPS7A45xx TPS7A45xx www.ti.com ...................................................................................................................................................................................................... SLVS720 – JUNE 2008 ELECTRICAL CHARACTERISTICS (1) Over operating temperature range TJ = –40°C to 125°C (unless otherwise noted) PARAMETER Minimum input voltage (3) (4) VIN TEST CONDITIONS ILOAD = 1.5 A Full range 2.1 2.5 VIN = 2.5 V to 20 V, ILOAD = 1 mA to 1.5 A VIN = 2.3 V, ILOAD = 1 mA VIN = 2.8 V to 20 V, ILOAD = 1 mA to 1.5 A Regulated output voltage (5) VIN = 3 V, ILOAD = 1 mA TPS7A4525 VIN = 3.5 V to 20 V, ILOAD = 1 mA to 1.5 A VIN = 3.8 V, ILOAD = 1 mA TPS7A4533 VIN = 4.3 V to 20 V, ILOAD = 1 mA to 1.5 A VIN = 2.21 V, ILOAD = 1 mA Line regulation 25°C 1.485 1.5 1.515 Full range 1.447 1.5 1.545 25°C 1.782 1.8 1.818 Full range 1.737 1.8 1.854 25°C 2.475 2.5 2.525 Full range 2.412 2.5 2.575 25°C 3.266 3.3 3.333 3.2 3.3 3.4 Full range 25°C 1.197 1.21 1.222 VIN = 2.5 V to 20 V, ILOAD = 1 mA to 1.5 A Full range 1.174 1.21 1.246 TPS7A4515 ΔVIN = 2.21 V to 20 V, ILOAD = 1 mA Full range 2 6 TPS7A4518 ΔVIN = 2.3 V to 20 V, ILOAD = 1 mA Full range 2.5 7 TPS7A4525 ΔVIN = 3 V to 20 V, ILOAD = 1 mA Full range 3 10 TPS7A4533 ΔVIN = 3.8 V to 20 V, ILOAD = 1 mA Full range 3.5 10 TPS7A4501 (3) ΔVIN = 2.21 V to 20 V, ILOAD = 1 mA Full range 1.5 3 TPS7A4515 VIN = 2.5 V, ΔILOAD = 1 mA to 1.5 A TPS7A4518 VIN = 2.8 V, ΔILOAD = 1 mA to 1.5 A TPS7A4525 VIN = 3.5 V, ΔILOAD = 1 mA to 1.5 A Full range TPS7A4533 VIN = 4.3 V, ΔILOAD = 1 mA to 1.5 A -40°C to +85°C 30 Full range 70 TPS7A4501 25°C 25°C 25°C TPS7A4501 (2) (3) (4) (5) VIN = 2.5 V, ΔILOAD = 1 mA to 1.5 A UNIT V V V mV 9 18 2 Full range 25°C (3) 2 Full range 25°C Load regulation (1) MAX 1.9 TPS7A4518 ADJ pin voltage (3) (5) TYP (2) 25°C VIN = 2.21 V, ILOAD = 1 mA VADJ MIN ILOAD = 0.5 A TPS7A4515 VOUT TJ 10 20 2.5 15 30 3 2 20 mV 8 -40°C to +85°C 8 Full range 18 The TPS7A45xx regulators are tested and specified under pulse load conditions such that TJ ≈ TA. They are fully tested at TA = 25°C. Performance at –40°C and 125°C is specified by design, characterization, and correlation with statistical process controls. Typical values represent the likely parametric nominal values determined at the time of characterization. Typical values depend on the application and configuration and may vary over time. Typical values are not ensured on production material. The TPS7A4501 is tested and specified for these conditions with the ADJ pin connected to the OUT pin. For the TPS7A4501, TPS7A4515 and TPS7A4518, dropout voltages are limited by the minimum input voltage specification under some output voltage/load conditions. Operating conditions are limited by maximum junction temperature. The regulated output voltage specification does not apply for all possible combinations of input voltage and output current. When operating at maximum input voltage, the output current range must be limited. When operating at maximum output current, the input voltage range must be limited. Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TPS7A45xx 3 TPS7A45xx SLVS720 – JUNE 2008 ...................................................................................................................................................................................................... www.ti.com ELECTRICAL CHARACTERISTICS (continued) Over operating temperature range TJ = –40°C to 125°C (unless otherwise noted) PARAMETER TEST CONDITIONS VDO Output voltage noise IADJ ADJ pin bias current (3) (9) Shutdown threshold ISHDN 0.085 0.10 0.17 0.180 0.13 25°C Full range 0.300 Full range 0.450 Full range 1 1.5 ILOAD = 1 mA Full range 1.1 1.6 ILOAD = 100 mA Full range 3.3 3.5 ILOAD = 500 mA Full range 15 17 ILOAD = 1.5 A Full range 80 90 25°C 35 25°C VOUT = OFF to ON Full range VOUT = ON to OFF Full range 0.25 3 7 0.9 2 0.75 0.01 1 VSHDN = 20 V 25°C 3 20 Quiescent current in shutdown VIN = 6 V, VSHDN = 0 V 25°C 0.01 1 Ripple rejection VIN – VOUT = 1.5 V (avg), VRIPPLE = 0.5 VP-P, fRIPPLE = 120 Hz, ILOAD = 0.75 A 25°C 68 IIL Input reverse leakage current Reverse output current (10) VIN = 7 V, VOUT = 0 V 25°C VIN = VOUT(NOMINAL) + 1 Full range VIN = –20 V, VOUT = 0 V Full range mA µVRMS 25°C Current limit V 0.350 ILOAD = 0 mA COUT = 10 µF, ILOAD = 1.5 A, BW = 10 Hz to 100 kHz UNIT 0.250 25°C VSHDN = 0 V SHDN pin current ILIMIT IRO 0.05 Full range ILOAD = 1.5 A eN MAX 0.02 0.06 25°C ILOAD = 100 mA Dropout voltage VIN = VOUT(NOMINAL) GND pin current (7) (8) VIN = VOUT(NOMINAL) + 1 TYP (2) Full range ILOAD = 500 mA IGND MIN 25°C ILOAD = 1 mA (4) (6) (7) TJ µA V µA µA dB 2 A 1.6 300 TPS7A4515 VOUT = 1.5 V, VIN < 1.5 V 25°C 600 1000 TPS7A4518 VOUT = 1.8 V, VIN < 1.8 V 25°C 600 1000 TPS7A4525 VOUT = 2.5 V, VIN < 2.5 V 25°C 600 1000 TPS7A4533 VOUT = 3.3 V, VIN < 3.3 V 25°C 600 1000 TPS7A4501 VOUT = 1.21 V, VIN < 1.21 V 25°C 300 500 µA µA (6) Dropout voltage is the minimum input to output voltage differential needed to maintain regulation at a specified output current. In dropout, the output voltage is equal to: VIN – VDROPOUT. (7) To satisfy requirements for minimum input voltage, the TPS7A4501 is tested and specified for these conditions with an external resistor divider (two 4.12-kΩ resistors) for an output voltage of 2.4 V. The external resistor divider adds a 300-mA DC load on the output. (8) GND pin current is tested with VIN = (VOUT(NOMINAL) + 1 V) and a current source load. The GND pin current decreases at higher input voltages. (9) ADJ pin bias current flows into the ADJ pin. (10) Reverse output current is tested with the IN pin grounded and the OUT pin forced to the rated output voltage. This current flows into the OUT pin and out the GND pin. 4 Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TPS7A45xx TPS7A45xx www.ti.com ...................................................................................................................................................................................................... SLVS720 – JUNE 2008 DEVICE INFORMATION TERMINAL FUNCTIONS PIN NO. 1 DESCRIPTION NAME SHDN Shutdown. SHDN is used to put the TPS7A45xx regulators into a low-power shutdown state. The output is off when SHDN is pulled low. SHDN can be driven either by 5-V logic or open-collector logic with a pullup resistor. The pullup resistor is required to supply the pullup current of the open-collector gate, normally several microamperes, and SHDN current, typically 3 mA. If unused, SHDN must be connected to VIN. The device is in the low-power shutdown state if SHDN is not connected. Input. Power is supplied to the device through IN. A bypass capacitor is required on this pin if the device is more than six inches away from the main input filter capacitor. In general, the output impedance of a battery rises with frequency, so it is advisable to include a bypass capacitor in battery-powered circuits. A bypass capacitor in the range of 1 µF to 10 µF is sufficient. The TPS7A45xx regulators are designed to withstand reverse voltages on IN with respect to ground and on OUT. In the case of a reverse input, which can happen if a battery is plugged in backwards, the device acts as if there is a diode in series with its input. There is no reverse current flow into the regulator, and no reverse voltage appears at the load. The device protects both itself and the load. 2 IN 3 GND Ground 4 OUT Output. The output supplies power to the load. A minimum output capacitor of 10 µF is required to prevent oscillations. Larger output capacitors are required for applications with large transient loads to limit peak voltage transients. 5 ADJ Adjust. For the adjustable version only (TPS7A4501), this is the input to the error amplifier. ADJ is internally clamped to ±7 V. It has a bias current of 3 mA that flows into the pin. ADJ voltage is 1.21 V referenced to ground, and the output voltage range is 1.21 V to 20 V. SENSE Sense. For fixed-voltage versions (TPS7A4515, TPS7A4518, TPS7A4525, and TPS7A4533), SENSE is the input to the error amplifier. Optimum regulation is obtained at the point where SENSE is connected to the OUT pin of the regulator. In critical applications, small voltage drops are caused by the resistance (RP) of PC traces between the regulator and the load. These may be eliminated by connecting SENSE to the output at the load as shown in Figure 32. Note that the voltage drop across the external PC traces adds to the dropout voltage of the regulator. SENSE bias current is 600 mA at the rated output voltage. SENSE can be pulled below ground (as in a dual supply system in which the regulator load is returned to a negative supply) and still allow the device to start and operate. 5 Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TPS7A45xx 5 TPS7A45xx SLVS720 – JUNE 2008 ...................................................................................................................................................................................................... www.ti.com TYPICAL CHARACTERISTICS DROPOUT VOLTAGE vs OUTPUT CURRENT DROPOUT VOLTAGE vs TEMPERATURE 500 480 450 IOUT = 1.5 A 400 Dropout Voltage – mV Dropout Voltage – mV 360 350 TA = 125°C 300 250 200 TA = 25°C 150 240 IOUT = 0.5 A IOUT = 100 mA 120 100 50 IOUT = 1 mA 0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 0 -50 1.6 25 50 75 Output Current – A Figure 1. Figure 2. QUIESCENT CURRENT vs TEMPERATURE OUTPUT VOLTAGE vs TEMPERATURE 100 125 100 125 1.84 VIN = 6 V 1.4 1.3 VOUT Fixed 1.8 V 1.83 IOUT = 0 A IOUT = 1 mA VSHDN = VIN 1.82 1.2 1.1 Output Voltage – V Quiescent Current – mA 0 TA – Free-Air Temperature – °C 1.5 VOUT Fixed 3.3 V 1 0.9 VOUT Adjustable 0.8 1.81 1.8 1.79 1.78 0.7 1.77 0.6 0.5 -50 6 -25 1.76 -25 0 25 50 75 100 125 -50 -25 0 25 50 75 TA – Free-Air Temperature – °C TA – Free-Air Temperature – °C Figure 3. Figure 4. Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TPS7A45xx TPS7A45xx www.ti.com ...................................................................................................................................................................................................... SLVS720 – JUNE 2008 TYPICAL CHARACTERISTICS (continued) OUTPUT VOLTAGE vs TEMPERATURE OUTPUT VOLTAGE vs TEMPERATURE 2.58 3.38 VOUT Fixed 2.5 V 2.56 Output Voltage – V Output Voltage – V IOUT = 1 mA 3.34 2.54 2.52 2.5 2.48 3.32 3.3 3.28 2.46 3.26 2.44 3.24 2.42 -50 VOUT Fixed 3.3 V 3.36 IOUT = 1 mA 3.22 -25 0 25 50 75 100 -50 125 -25 TA – Free-Air Temperature – °C Figure 5. 0 OUTPUT VOLTAGE vs TEMPERATURE 100 125 TJ = 25°C VOUT Adjustable IOUT = 1 mA ROUT = 4.3 k W 1 VSHDN = VIN VIN = 6 V 1.215 1.21 1.205 1.2 VOUT Adjustable 0.8 0.6 0.4 0.2 1.195 1.19 -50 75 1.2 Quiescent Current – mA Output Voltage – V 1.22 50 QUIESCENT CURRENT vs INPUT VOLTAGE 1.23 1.225 25 TA – Free-Air Temperature – °C Figure 6. 0 -25 0 25 50 75 100 125 0 2 TA – Free-Air Temperature – °C Figure 7. 4 6 8 10 12 14 16 18 20 Input Voltage – V Figure 8. Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TPS7A45xx 7 TPS7A45xx SLVS720 – JUNE 2008 ...................................................................................................................................................................................................... www.ti.com TYPICAL CHARACTERISTICS (continued) GROUND CURRENT vs INPUT VOLTAGE GROUND CURRENT vs INPUT VOLTAGE 100 10 90 TJ = 25°C VSHDN = VIN VSHDN = VIN VOUT Adjustable 80 8 VOUT Adjustable VOUT = 1.21 V 70 VOUT = 1.21 V 60 Ground Current – mA Ground Current – mA TJ = 25°C IOUT = 1.5 A 50 40 IOUT = 1 A 30 6 IOUT = 300 mA 4 IOUT = 100 mA 20 2 IOUT = 0.5 A 10 IOUT = 10 mA 0 0 0 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 7 Input Voltage – V Input Voltage – V Figure 9. Figure 10. GROUND CURRENT vs INPUT VOLTAGE GROUND CURRENT vs INPUT VOLTAGE 40 8 9 10 120 TJ = 25°C TJ = 25°C VSHDN = VIN 35 VSHDN = VIN 100 VOUT Fixed 3.3 V VOUT Fixed 3.3 V Ground Current – mA Ground Current – mA 30 25 IOUT = 300 mA 20 IOUT = 100 mA 15 IOUT = 10 mA 80 IOUT = 1.5 A 60 40 IOUT = 1 A 10 20 IOUT = 0.5 A 5 0 0 0 8 1 2 3 4 5 6 7 8 9 10 0 1 2 3 4 5 6 Input Voltage – V Input Voltage – V Figure 11. Figure 12. Submit Documentation Feedback 7 8 9 10 Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TPS7A45xx TPS7A45xx www.ti.com ...................................................................................................................................................................................................... SLVS720 – JUNE 2008 TYPICAL CHARACTERISTICS (continued) GROUND CURRENT vs OUTPUT CURRENT SHDN INPUT CURRENT vs TEMPERATURE 1 80 VIN = VOUT(nom) + 1 VSHDN = 0 V 70 SHDN Input Current – µA Ground Current – mA 60 50 40 30 20 0.75 0.5 0.25 10 0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 0 -50 1.6 -25 0 25 50 75 Output Current – A TA – Free-Air Temperature – °C Figure 13. Figure 14. SHDN INPUT CURRENT vs SHDN INPUT VOLTAGE SHDN THRESHOLD (OFF TO ON) vs TEMPERATURE 2.5 1 2.25 0.9 2 0.8 100 125 100 125 SHDN Input Voltage – V SHDN Input Current – µA IOUT = 1 mA 1.75 1.5 1.25 1 0.75 0.7 0.6 0.5 0.4 0.3 0.5 0.2 0.25 0.1 0 0 2 4 6 8 10 12 14 16 18 20 0 -50 -25 0 25 50 75 SHDN Input Voltage – V TA – Free-Air Temperature – °C Figure 15. Figure 16. Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TPS7A45xx 9 TPS7A45xx SLVS720 – JUNE 2008 ...................................................................................................................................................................................................... www.ti.com TYPICAL CHARACTERISTICS (continued) SHDN THRESHOLD (ON TO OFF) vs TEMPERATURE ADJ BIAS CURRENT vs TEMPERATURE 5 1 0.9 4.5 0.8 4 0.7 3.5 ADJ Bias Current – µA SHDN Input Voltage – V IOUT = 1 mA 0.6 0.5 0.4 0.3 3 2.5 2 1.5 0.2 1 0.1 0.5 0 -50 -25 0 25 50 75 100 0 -50 125 -25 0 25 50 75 TA – Free-Air Temperature – °C Figure 17. TA – Free-Air Temperature – °C CURRENT LIMIT vs INPUT/OUTPUT DIFFERENTIAL VOLTAGE CURRENT LIMIT vs TEMPERATURE 100 125 100 125 Figure 18. 3.5 5 D ?VOUT = 100 mV VIN = 7 V 3 VOUT = 0 V TA = -40°C 4 TA = 25°C Current Limit – A Current Limit – A 2.5 2 TA = 125°C 1.5 3 2 1 1 0.5 0 0 10 2 4 6 8 10 12 14 16 18 20 0 -50 Input/Output Differential Voltage – V -25 0 25 50 75 TA – Free-Air Temperature – °C Figure 19. Figure 20. Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TPS7A45xx TPS7A45xx www.ti.com ...................................................................................................................................................................................................... SLVS720 – JUNE 2008 TYPICAL CHARACTERISTICS (continued) REVERSE OUTPUT CURRENT vs OUTPUT VOLTAGE REVERSE OUTPUT CURRENT vs TEMPERATURE 1000 12 TJ = 25°C VIN = 0 V VIN = 0 V Current flows into OUT pin Reverse Output Current – µA Reverse Output Current – mA 10 8 VOUT Adjustable 6 VOUT = VADJ 4 2 800 600 VOUT Fixed 3.3V VOUT = 3.3 V 400 VOUT Adjustable 200 0 VOUT Fixed 3.3 V VOUT = 1.21 V VOUT = VFB -2 0 2 4 6 8 0 -50 10 -25 0 25 50 75 100 125 100 125 TA – Free-Air Temperature – °C Figure 22. Output Voltage – V Figure 21. RIPPLE REJECTION vs FREQUENCY LOAD REGULATION vs TEMPERATURE 80 20 IOUT = 1.5 A 15 70 10 Load Regulation – mV Ripple Rejection – dB 60 50 40 30 VIN = 2.7 V CIN = 0 20 COUT = 10 µF 0 -5 -10 -15 VOUT Fixed 1.8 V VOUT Fixed 2.5 V -20 -25 IOUT = 750 mA 10 VOUT Adjustable 5 VOUT Fixed 3.3 V -30 VRipple = 0.05 Vpp -35 0 10 100 1000 1k 10000 10k 100000 100k 100000 1M -50 -25 0 25 50 75 TA – Free-Air Temperature – °C Frequency – Hz Figure 23. Figure 24. Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TPS7A45xx 11 TPS7A45xx SLVS720 – JUNE 2008 ...................................................................................................................................................................................................... www.ti.com TYPICAL CHARACTERISTICS (continued) OUTPUT NOISE VOLTAGE vs FREQUENCY LOAD TRANSIENT RESPONSE 1 COUT = 10 µF Change in Outupt Voltage CIN = 10 µF IOUT = 1.5 A VOUT Fixed 3.3 V 0.1 Load Current Output Noise Voltage – µVRMS VIN = 4.3 V COUT = 10 µF VOUT Adjustable 0.01 10 100 1k Frequency - Hz 20 mV VOUT 0 mV -20 mV 500 mA IOUT 10 mA 500 µs per division 100k 10k Figure 25. Figure 26. LOAD TRANSIENT RESPONSE VIN = 4.3 V Change in Outupt Voltage CIN = 10 µF COUT = 10 µF VOUT 20 mV 0 mV Load Current -20 mV 1.5 A IOUT 10 mA 500 µs per division Figure 27. 12 Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TPS7A45xx TPS7A45xx www.ti.com ...................................................................................................................................................................................................... SLVS720 – JUNE 2008 TYPICAL CHARACTERISTICS (continued) LINE TRANSIENT RESPONSE IOUT = 1.5 A CIN = 10 µF VIN 4.3 V 5 mV VOUT -5 mV Change in Output Voltage 5.3 V Input Voltage COUT = 10 µF Figure 28. Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TPS7A45xx 13 TPS7A45xx SLVS720 – JUNE 2008 ...................................................................................................................................................................................................... www.ti.com APPLICATION INFORMATION The TPS7A45xx series are 1.5-A low-dropout regulators optimized for fast transient response. The devices are capable of supplying 1.5 A at a dropout voltage of 300 mV. The low operating quiescent current (1 mA) drops to less than 1 µA in shutdown. In addition to the low quiescent current, the TPS7A45xx regulators incorporate several protection features that make them ideal for use in battery-powered systems. The devices are protected against both reverse input and reverse output voltages. In battery-backup applications where the output can be held up by a backup battery when the input is pulled to ground, the TPS7A45xx acts as if it has a diode in series with its output and prevents reverse current flow. Additionally, in dual-supply applications where the regulator load is returned to a negative supply, the output can be pulled below ground by as much as 20 V and still allow the device to start and operate. Typical Applications IN VIN > 3 V 10 µF (see Note A) 2.5 V at 1.5 A OUT 10 µF (see Note A) TPS7A4525 SHDN SENSE GND Figure 29. 3.3 V to 2.5 V Regulator R5 0.01k VIN > 2.7 V C1 10 µF TPS7A4518 OUT IN R1 1k + R2 80.6k R4 2.2k R6 2.2k FB SHDN GND C3 1 µF R3 2k + C2 3.3 µF LOAD R8 100k R7 470k - Figure 30. Adjustable Current Source 14 Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TPS7A45xx TPS7A45xx www.ti.com ...................................................................................................................................................................................................... SLVS720 – JUNE 2008 R1 0.01k IN VIN > 3.7 V 3.3 V at 3 A OUT TPS7A4533 C1 10 µF C2 22 µF FB SHDN GND R2 0.01k IN OUT R6 6.65k TPS7A4501 SHDN FB GND SHDN R7 4.12k R3 2.2k R4 2.2k R5 1k + – C3 0.01 µF Figure 31. Paralleling Regulators for Higher Output Current RP IN OUT TPS7A4501 VIN SHDN SENSE Load GND RP Figure 32. Kelvin Sense Connection Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TPS7A45xx 15 TPS7A45xx SLVS720 – JUNE 2008 ...................................................................................................................................................................................................... www.ti.com Adjustable Operation The adjustable version of the TPS7A45xx has an output voltage range of 1.21 V to 20 V. The output voltage is set by the ratio of two external resistors as shown in Figure 33. The device maintains the voltage at the ADJ pin at 1.21 V referenced to ground. The current in R1 is then equal to (1.21 V/R1), and the current in R2 is the current in R1 plus the ADJ pin bias current. The ADJ pin bias current, 3 µA at 25°C, flows through R2 into the ADJ pin. The output voltage can be calculated using the formula shown in Figure 33. The value of R1 should be less than 4.17 kΩ to minimize errors in the output voltage caused by the ADJ pin bias current. Note that in shutdown the output is turned off, and the divider current is zero. IN VOUT OUT TPS7A4501 R2 VIN ADJ GND R1 ceramic capacitors. Ceramic capacitors are manufactured with a variety of dielectrics, each with different behavior over temperature and applied voltage. The most common dielectrics used are Z5U, Y5V, X5R and X7R. The Z5U and Y5V dielectrics are good for providing high capacitances in a small package, but exhibit strong voltage and temperature coefficients. When used with a 5-V regulator, a 10-µF Y5V capacitor can exhibit an effective value as low as 1 µF to 2 µF over the operating temperature range. The X5R and X7R dielectrics result in more stable characteristics and are more suitable for use as the output capacitor. The X7R type has better stability across temperature, while the X5R is less expensive and is available in higher values. Voltage and temperature coefficients are not the only sources of problems. Some ceramic capacitors have a piezoelectric response. A piezoelectric device generates voltage across its terminals due to mechanical stress, similar to the way a piezoelectric accelerometer or microphone works. For a ceramic capacitor the stress can be induced by vibrations in the system or thermal transients. Overload Recovery R2 + (I ADJ)(R2) VOUT = 1.21 V )1 + R1) VADJ = 1.21 V IADJ = 3 µA at 25°C Output range = 1.21 V to 20 V Figure 33. Adjustable Operation The adjustable device is tested and specified with the ADJ pin tied to the OUT pin for an output voltage of 1.21 V. Specifications for output voltages greater than 1.21 V are proportional to the ratio of the desired output voltage to 1.21 V: VOUT/1.21 V. For example, load regulation for an output current change of 1 mA to 1.5 A is –3 mV (typ) at VOUT = 1.21 V. At VOUT = 5 V, load regulation is: (5 V/1.21 V)(–3 mV) = –12.4 mV Output Capacitance and Transient Response The TPS7A45xx regulators are designed to be stable with a wide range of output capacitors. The ESR of the output capacitor affects stability, most notably with small capacitors. A minimum output capacitor of 10 µF with an ESR of 3 Ω or less is recommended to prevent oscillations. Larger values of output capacitance can decrease the peak deviations and provide improved transient response for larger load current changes. Bypass capacitors, used to decouple individual components powered by the TPS7A45xx, increase the effective output capacitor value. Like many IC power regulators, the TPS7A45xx has safe operating area protection. The safe area protection decreases the current limit as input-to-output voltage increases and keeps the power transistor inside a safe operating region for all values of input-to-output voltage. The protection is designed to provide some output current at all values of input-to-output voltage up to the device breakdown. When power is first turned on, as the input voltage rises, the output follows the input, allowing the regulator to start up into very heavy loads. During start up, as the input voltage is rising, the input-to-output voltage differential is small, allowing the regulator to supply large output currents. With a high input voltage, a problem can occur wherein removal of an output short does not allow the output voltage to recover. Other regulators also exhibit this phenomenon, so it is not unique to the TPS7A45xx. The problem occurs with a heavy output load when the input voltage is high and the output voltage is low. Common situations occur immediately after the removal of a short circuit or when the shutdown pin is pulled high after the input voltage has already been turned on. The load line for such a load may intersect the output current curve at two points. If this happens, there are two stable output operating points for the regulator. With this double intersection, the input power supply may need to be cycled down to zero and brought up again to make the output recover. Extra consideration must be given to the use of 16 Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TPS7A45xx TPS7A45xx www.ti.com ...................................................................................................................................................................................................... SLVS720 – JUNE 2008 Output Voltage Noise The TPS7A45xx regulators have been designed to provide low output voltage noise over the 10-Hz to 100-kHz bandwidth while operating at full load. Output voltage noise is typically 35 nV/√Hz over this frequency bandwidth for the TPS7A4501 (adjustable version). For higher output voltages (generated by using a resistor divider), the output voltage noise is gained up accordingly. This results in RMS noise over the 10-Hz to 100-kHz bandwidth of 14 µVRMS for the TPS7A4501, increasing to 38 µVRMS for the TPS7A4533. Higher values of output voltage noise may be measured when care is not exercised with regard to circuit layout and testing. Crosstalk from nearby traces can induce unwanted noise onto the output of the TPS7A45xx. Power-supply ripple rejection must also be considered; the TPS7A45xx regulators do not have unlimited power-supply rejection and pass a small portion of the input noise through to the output. Thermal Considerations The power handling capability of the device is limited by the maximum rated junction temperature (125°C). The power dissipated by the device is made up of two components: 1. Output current multiplied by the input/output voltage differential: IOUT(VIN – VOUT) 2. GND pin current multiplied by the input voltage: IGNDVIN. The GND pin current can be found using the GND Pin Current graphs in Typical Characteristics. Power dissipation is equal to the sum of the two components listed above. The TPS7A45xx series regulators have internal thermal limiting designed to protect the device during overload conditions. For continuous normal conditions, the maximum junction temperature rating of 125°C must not be exceeded. It is important to give careful consideration to all sources of thermal resistance from junction to ambient. Additional heat sources mounted nearby must also be considered. For surface-mount devices, heat sinking is accomplished by using the heat-spreading capabilities of the PC board and its copper traces. Copper board stiffeners and plated through-holes can also be used to spread the heat generated by power devices. Table 1 lists thermal resistance for several different board sizes and copper areas. All measurements were taken in still air on 1/16" FR-4 board with 1-oz copper. Table 1. Thermal Data COPPER AREA TOPSIDE (1) BACKSIDE BOARD AREA THERMAL RESISTANCE (JUNCTION TO AMBIENT) KTT Package (5-Pin TO-263) 2 2500 mm2 2500 mm2 23°C/W 2 1000 mm 2 2500 mm 2500 mm2 25°C/W 125 mm2 2500 mm2 2500 mm2 33°C/W 2500 mm (1) Device is mounted on topside. Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TPS7A45xx 17 TPS7A45xx SLVS720 – JUNE 2008 ...................................................................................................................................................................................................... www.ti.com Calculating Junction Temperature Example: Given an output voltage of 3.3 V, an input voltage range of 4 V to 6 V, an output current range of 0 mA to 500 mA, and a maximum ambient temperature of 50°C, what is the maximum junction temperature? The power dissipated by the device is equal to: IOUT(MAX)(VIN(MAX) – VOUT) + IGND(VIN(MAX)) where, IOUT(MAX) = 500 mA VIN(MAX) = 6 V IGND at (IOUT = 500 mA, VIN = 6 V) = 10 mA So, P = 500 mA × (6 V – 3.3 V) + 10 mA × 6 V = 1.41 W Using a KTT package, the thermal resistance is in the range of 23°C/W to 33°C/W, depending on the copper area. So the junction temperature rise above ambient is approximately equal to: 1.41 W × 28°C/W = 39.5°C The maximum junction temperature is then be equal to the maximum junction-temperature rise above ambient plus the maximum ambient temperature or: TJMAX = 50°C + 39.5°C = 89.5°C Protection Features The TPS7A45xx regulators incorporate several protection features which make them ideal for use in battery-powered circuits. In addition to the normal protection features associated with monolithic regulators, such as current limiting and thermal limiting, the devices are protected against reverse input voltages, reverse output voltages and reverse voltages from output to input. Current limit protection and thermal overload protection are intended to protect the device against current overload conditions at the output of the device. For normal operation, the junction temperature should not exceed 125°C. The input of the device withstands reverse voltages of 20 V. Current flow into the device is limited to less than 1 mA (typically less than 100 µA), and no negative voltage appears at the output. The device protects both itself and the load. This provides protection against batteries that can be plugged in backward. 18 The output of the TPS7A45xx can be pulled below ground without damaging the device. If the input is left open circuit or grounded, the output can be pulled below ground by 20 V. For fixed voltage versions, the output acts like a large resistor, typically 5 kΩ or higher, limiting current flow to typically less than 600 µA. For adjustable versions, the output acts like an open circuit; no current flows out of the pin. If the input is powered by a voltage source, the output sources the short-circuit current of the device and protects itself by thermal limiting. In this case, grounding the SHDN pin turns off the device and stops the output from sourcing the short-circuit current. The ADJ pin of the adjustable device can be pulled above or below ground by as much as 7 V without damaging the device. If the input is left open circuit or grounded, the ADJ pin acts like an open circuit when pulled below ground and like a large resistor (typically 5 kΩ) in series with a diode when pulled above ground. In situations where the ADJ pin is connected to a resistor divider that would pull the ADJ pin above its 7-V clamp voltage if the output is pulled high, the ADJ pin input current must be limited to less than 5 mA. For example, a resistor divider is used to provide a regulated 1.5-V output from the 1.21-V reference when the output is forced to 20 V. The top resistor of the resistor divider must be chosen to limit the current into the ADJ pin to less than 5 mA when the ADJ pin is at 7 V. The 13-V difference between OUT and ADJ divided by the 5-mA maximum current into the ADJ pin yields a minimum top resistor value of 2.6 kΩ. In circuits where a backup battery is required, several different input/output conditions can occur. The output voltage may be held up while the input is either pulled to ground, pulled to some intermediate voltage, or is left open circuit. When the IN pin of the TPS7A45xx is forced below the OUT pin or the OUT pin is pulled above the IN pin, input current typically drops to less than 2 µA. This can happen if the input of the device is connected to a discharged (low voltage) battery and the output is held up by either a backup battery or a second regulator circuit. The state of the SHDN pin has no effect on the reverse output current when the output is pulled above the input. Submit Documentation Feedback Copyright © 2008, Texas Instruments Incorporated Product Folder Link(s): TPS7A45xx IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. 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