TPS73101, TPS73115, TPS73118 TPS73125, TPS73130, TPS73132 TPS73133, TPS73150 www.ti.com SBVS034E – SEPTEMBER 2003 – REVISED SEPTEMBER 2004 Cap-Free, NMOS, 150mA Low Dropout Regulator with Reverse Current Protection FEATURES • • • • • • • • • • • Stable with No Output Capacitor or Any Value or Type of Capacitor Input Voltage Range of 1.7V to 5.5V Ultralow Dropout Voltage: 30mV Typ Excellent Load Transient Response—with or without Optional Output Capacitor New NMOS Topology Provides Low Reverse Leakage Current Low Noise: 30µVRMS Typ (10kHz to 100kHz) 0.5% Initial Accuracy 1% Overall Accuracy over Line, Load, and Temperature Less Than 1µA Max IQ in Shutdown Mode Thermal Shutdown and Specified Min/Max Current Limit Protection Available in Multiple Output Voltage Versions – Fixed Outputs of 1.2V, 1.5V, 1.8V, 2.5V, 3.0V, 3.3V, and 5.0V – Adjustable Outputs From 1.20V to 5.5V – Custom Outputs Available DESCRIPTION The TPS731xx family of low-dropout (LDO) linear voltage regulators uses a new topology: an NMOS pass element in a voltage-follower configuration. This topology is stable using output capacitors with low ESR, and even allows operation without a capacitor. It also provides high reverse blockage (low reverse current) and ground pin current that is nearly constant over all values of output current. The TPS731xx uses an advanced BiCMOS process to yield high precision while delivering very low dropout voltages and low ground pin current. Current consumption, when not enabled, is under 1µA and ideal for portable applications. The extremely low output noise (30µVRMS with 0.1µF CNR) is ideal for powering VCOs. These devices are protected by thermal shutdown and foldback current limit. DBV PACKAGE SOT23 (TOP VIEW) IN 1 GND 2 EN 3 5 OUT 4 NR/FB APPLICATIONS • • • • Portable/Battery-Powered Equipment Post-Regulation for Switching Supplies Noise-Sensitive Circuitry such as VCOs Point of Load Regulation for DSPs, FPGAs, ASICs, and Microprocessors Optional VIN Optional IN VOUT OUT TPS731xx EN GND NR Optional Typical Application Circuit for Fixed-Voltage Versions 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. 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 © 2003–2004, Texas Instruments Incorporated TPS73101, TPS73115, TPS73118 TPS73125, TPS73130, TPS73132 TPS73133, TPS73150 www.ti.com SBVS034E – SEPTEMBER 2003 – REVISED SEPTEMBER 2004 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) (3) PRODUCT VOUT (1) PACKAGE-LEAD (DESIGNATOR) (2) SPECIFIED TEMPERATURE RANGE PACKAGE MARKING TPS73101 Adjustable or 1.2V (3) SOT23-5 (DBV) -40°C to +125°C PWYQ TPS73115 1.5V SOT23-5 (DBV) -40°C to +125°C T31 TPS73118 1.8V SOT23-5 (DBV) -40°C to +125°C T32 TPS73125 2.5V SOT23-5 (DBV) -40°C to +125°C PHWI TPS73130 3.0V SOT23-5 (DBV) -40°C to +125°C T33 TPS73132 3.2V SOT23-5 (DBV) -40°C to +125°C T52 TPS73133 3.3V SOT23-5 (DBV) -40°C to +125°C T34 TPS73150 5.0V SOT23-5 (DBV) -40°C to +125°C T35 ORDERING NUMBER TRANSPORT MEDIA, QUANTITY TPS73101DBVT Tape and Reel, 250 TPS73101DBVR Tape and Reel, 3000 TPS73115DBVT Tape and Reel, 250 TPS73115DBVR Tape and Reel, 3000 TPS73118DBVT Tape and Reel, 250 TPS73118DBVR Tape and Reel, 3000 TPS73125DBVT Tape and Reel, 250 TPS73125DBVR Tape and Reel, 3000 TPS73130DBVT Tape and Reel, 250 TPS73130DBVR Tape and Reel, 3000 TPS73132DBVT Tape and Reel, 250 TPS73132DBVR Tape and Reel, 3000 TPS73133DBVT Tape and Reel, 250 TPS73133DBVR Tape and Reel, 3000 TPS73150DBVT Tape and Reel, 250 TPS73150DBVR Tape and Reel, 3000 Custom output voltages from 1.3V to 4V in 100mV increments are available on a quick-turn basis for prototyping. Minimum order quantities apply; contact factory for details and availability. For the most current specification and package information, refer to the Package Option Addendum located at the end of this datasheet. For fixed 1.2V operation, tie FB to OUT. ABSOLUTE MAXIMUM RATINGS over operating junction temperature range unless otherwise noted (1) TPS731xx UNIT VIN range -0.3 to 6.0 V VEN range -0.3 to 6.0 V -0.3 to 5.5 V VOUT range Peak output current Output short-circuit duration Internally limited Indefinite Continuous total power dissipation See Dissipation Ratings Table Junction temperature range, TJ -55 to +150 °C Storage temperature range -65 to +150 °C ESD rating, HBM 2 kV ESD rating, CDM 500 V (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 the Electrical Characteristics is not implied. Exposure to absolute maximum rated conditions for extended periods may affect device reliability. TPS73101, TPS73115, TPS73118 TPS73125, TPS73130, TPS73132 TPS73133, TPS73150 www.ti.com SBVS034E – SEPTEMBER 2003 – REVISED SEPTEMBER 2004 POWER DISSIPATION RATINGS (1) BOARD PACKAGE RΘJC RΘJA DERATING FACTOR ABOVE TA = 25°C TA ≤ 25°C POWER RATING TA = 70°C POWER RATING TA = 85°C POWER RATING Low-K (2) DBV 64°C/W 255°C/W 3.9mW/°C 390mW 215mW 155mW DBV 64°C/W 180°C/W 5.6mW/°C 560mW 310mW 225mW High-K (1) (2) (3) (3) See Power Dissipation in the Applications section for more information related to thermal design. The JEDEC Low-K (1s) board design used to derive this data was a 3 inch x 3 inch, two-layer board with 2-ounce copper traces on top of the board. The JEDEC High-K (2s2p) board design used to derive this data was a 3 inch x 3 inch, multilayer board with 1-ounce internal power and ground planes and 2-ounce copper traces on the top and bottom of the board. ELECTRICAL CHARACTERISTICS Over operating temperature range (TJ = -40°C to +125°C), VIN = VOUT(nom) + 0.5V (1), IOUT = 10mA, VEN = 1.7V, and COUT = 0.1µF, unless otherwise noted. Typical values are at TJ = 25°C. PARAMETER TEST CONDITIONS VIN Input voltage range (1) VFB Internal reference (TPS73101) ∆VOUT%/∆VIN Accuracy (1) TYP 1.7 V 1.210 V V VFB 5.5 - VDO Nominal TJ = 25°C -0.5 +0.5 VIN, IOUT, and T VOUT + 0.5V ≤ VIN ≤ 5.5V; 10 mA ≤ IOUT≤ 150mA -1.0 VOUT(nom) + 0.5V ≤ VIN ≤ 5.5V ±0.5 +1.0 0.01 1mA ≤ IOUT ≤ 150mA 0.002 10mA ≤ IOUT ≤ 150mA 0.0005 UNIT 5.5 1.198 Line regulation (1) 1.20 MAX TJ = 25°C Output voltage range (TPS73101) VOUT MIN % %/V ∆VOUT%/∆IOUT Load regulation VDO Dropout voltage (2) (VIN = VOUT (nom) - 0.1V) IOUT = 150mA ZO(DO) Output impedance in dropout 1.7 V ≤ VIN ≤ VOUT + VDO ICL Output current limit VOUT = 0.9 × VOUT(nom) ISC Short-circuit current VOUT = 0V 200 IREV Reverse leakage current (3) (-IIN) VEN ≤ 0.5V, 0V≤ VIN ≤ VOUT 0.1 10 IOUT = 10mA (IQ) 400 550 IOUT = 150mA 550 750 VEN ≤ 0.5V, VOUT ≤ VIN ≤ 5.5 0.02 1 µA 0.1 0.3 µA 30 100 mV 500 mA Ω 0.25 150 360 IGND Ground pin current ISHDN Shutdown current (IGND) IFB FB pin current (TPS73101) PSRR Power-supply rejection ratio (ripple rejection) f = 100Hz, IOUT = 150 mA 58 f = 10kHz, IOUT = 150 mA 37 VN Output noise voltage BW = 10Hz - 100kHz COUT = 10µF, No CNR 27 × VOUT COUT = 10µF, CNR = 0.01µF 8.5 × VOUT tSTR Startup time VOUT = 3V, RL = 30Ω COUT = 1 µF, CNR = 0.01 µF 600 VEN(HI) Enable high (enabled) VEN(LO) Enable low (shutdown) IEN(HI) Enable pin current (enabled) TSD Thermal shutdown temperature TJ Operating junction temperature (1) (2) (3) %/mA 1.7 0.02 Shutdown Temp increasing 160 Reset Temp decreasing 140 -40 µA µA dB µVRMS µs VIN 0 VEN = 5.5V mA V 0.5 V 0.1 µA °C 125 °C Minimum VIN = VOUT +VDO or 1.7V, whichever isgreater. VDO is not measured for the TPS73115 (VO(nom) = 1.5V) since minimum VIN = 1.7V. Fixed-voltage versions only; refer to the Applications section for more information. 3 TPS73101, TPS73115, TPS73118 TPS73125, TPS73130, TPS73132 TPS73133, TPS73150 www.ti.com SBVS034E – SEPTEMBER 2003 – REVISED SEPTEMBER 2004 FUNCTIONAL BLOCK DIAGRAMS IN 4MHz Charge Pump EN Thermal Protection Ref Servo 27kΩ Bandgap Error Amp Current Limit OUT 8kΩ GND R1 R1 + R2 = 80kΩ R2 NR Figure 1. Fixed Voltage Version Table 1. Standard 1% Resistor Values for Common Output Voltages IN 4MHz Charge Pump EN Thermal Protection Ref Servo 27kΩ Bandgap Error Amp OUT Current Limit GND 8kΩ 80kΩ R2 4 R1 R2 1.2V Short Open 1.5V 23.2kΩ 95.3kΩ 1.8V 28.0kΩ 56.2kΩ 2.5V 39.2kΩ 36.5kΩ 2.8V 44.2kΩ 33.2kΩ 3.0V 46.4kΩ 30.9kΩ 3.3V 52.3kΩ 30.1kΩ 5.0V 78.7kΩ 24.9kΩ NOTE: VOUT = (R1 + R2)/R2 × 1.204; R1R2 ≅ 19kΩ for best accuracy. R1 FB Figure 2. Adjustable Voltage Version VO TPS73101, TPS73115, TPS73118 TPS73125, TPS73130, TPS73132 TPS73133, TPS73150 www.ti.com SBVS034E – SEPTEMBER 2003 – REVISED SEPTEMBER 2004 PIN ASSIGNMENTS DBV PACKAGE SOT23 (TOP VIEW) IN 1 GND 2 EN 3 5 OUT 4 NR/FB TERMINAL FUNCTIONS TERMINAL NAME SOT23 (DBV) PIN NO. DESCRIPTION IN 1 Unregulated input supply GND 2 Ground EN 3 Driving the enable pin (EN) high turns on the regulator. Driving this pin low puts the regulator into shutdown mode. Refer to the Shutdown section under Applications Information for more details. EN can be connected to IN if not used. NR 4 Fixed voltage versions only—connecting an external capacitor to this pin bypasses noise generated by the internal bandgap, reducing output noise to very low levels. FB 4 Adjustable voltage version only—this is the input to the control loop error amplifier, and is used to set the output voltage of the device. OUT 5 Output of the regulator. There are no output capacitor requirements for stability. 5 TPS73101, TPS73115, TPS73118 TPS73125, TPS73130, TPS73132 TPS73133, TPS73150 www.ti.com SBVS034E – SEPTEMBER 2003 – REVISED SEPTEMBER 2004 TYPICAL CHARACTERISTICS For all voltage versions at TJ= 25°C, VIN = VOUT(nom) + 0.5V, IOUT = 10mA, VEN = 1.7V, and COUT = 0.1µF, unless otherwise noted. LOAD REGULATION LINE REGULATION 0.5 0.20 Referred to IOUT = 10mA 0.4 Change in VOUT (%) 0.3 Change in VOUT (%) Referred to VIN = VOUT + 0.5V at IOUT = 10mA 0.15 0.2 0.1 0 −0.1 −0.2 −0.3 0.10 0 −0.05 −40 C −0.10 −0.15 −0.4 −0.20 −0.5 0 15 30 45 60 75 90 105 120 135 150 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 VIN − VOUT (V) IOUT (mA) Figure 3. Figure 4. DROPOUT VOLTAGE vs OUTPUT CURRENT DROPOUT VOLTAGE vs TEMPERATURE 50 50 TPS73125DBV TPS73125DBV +125 C 40 30 +25 C 20 10 40 VDO (mV) VDO (mV) +25 C +125C 0.05 30 20 10 −40C 0 0 30 60 90 120 0 −50 150 IOUT (mA) −25 0 25 50 75 100 125 Temperature (C) Figure 5. Figure 6. OUTPUT VOLTAGE ACCURACY HISTOGRAM OUTPUT VOLTAGE DRIFT HISTOGRAM 30 18 I OUT = 10mA 16 25 I OUT = 10mA All Voltage Versions Percent of Units (%) Percent of Units (%) 14 20 15 10 12 10 8 6 4 5 2 6 −100 −90 −80 −70 −60 −50 −40 −30 −20 −10 0 10 20 30 40 50 60 70 80 90 100 0 −1.0 −0.9 −0.8 −0.7 −0.6 −0.5 −0.4 −0.3 −0.2 −0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0 VOUT Error (%) Worst Case dVOUT/dT (ppm/ C) Figure 7. Figure 8. TPS73101, TPS73115, TPS73118 TPS73125, TPS73130, TPS73132 TPS73133, TPS73150 www.ti.com SBVS034E – SEPTEMBER 2003 – REVISED SEPTEMBER 2004 TYPICAL CHARACTERISTICS (continued) For all voltage versions at TJ= 25°C, VIN = VOUT(nom) + 0.5V, IOUT = 10mA, VEN = 1.7V, and COUT = 0.1µF, unless otherwise noted. GROUND PIN CURRENT vs TEMPERATURE 700 600 600 500 500 IGND (µA) IGND (µA) GROUND PIN CURRENT vs OUTPUT CURRENT 700 400 300 200 400 300 VIN = 5.5V VIN = 4V VIN = 2V 200 VIN = 5.5V VIN = 4V VIN = 2V 100 100 0 0 30 60 90 120 0 −50 150 −25 0 25 50 75 100 I OUT (mA) Temperature ( C) Figure 9. Figure 10. CURRENT LIMIT vs VOUT (FOLDBACK) GROUND PIN CURRENT in SHUTDOWN vs TEMPERATURE 400 125 1 VENABLE = 0.5V VIN = VO + 0.5V 350 ICL 300 250 IGND (µA) Current Limit (mA) IOUT = 150mA ISC 200 150 0.1 100 50 TPS73133 0 0 0.5 1.0 1.5 2.0 2.5 3.0 0.01 −50 3.5 0 25 50 Temperature (C) Figure 11. Figure 12. CURRENT LIMIT vs VIN 75 100 125 CURRENT LIMIT vs TEMPERATURE 500 500 450 450 400 400 Current Limit (mA) Current Limit (mA) −25 VOUT (V) 350 300 250 200 350 300 250 200 150 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 150 −50 −25 0 25 50 VIN (V) Temperature (C) Figure 13. Figure 14. 75 100 125 7 TPS73101, TPS73115, TPS73118 TPS73125, TPS73130, TPS73132 TPS73133, TPS73150 www.ti.com SBVS034E – SEPTEMBER 2003 – REVISED SEPTEMBER 2004 TYPICAL CHARACTERISTICS (continued) For all voltage versions at TJ= 25°C, VIN = VOUT(nom) + 0.5V, IOUT = 10mA, VEN = 1.7V, and COUT = 0.1µF, unless otherwise noted. PSRR (RIPPLE REJECTION) vs FREQUENCY PSRR (RIPPLE REJECTION) vs VIN - VOUT 40 90 IOUT = 100mA COUT = Any Ripple Rejection (dB) 70 IOUT = 1mA COUT = 1µF 35 30 IOUT = 1mA COUT = 10µF 60 50 IO = 100mA CO = 1µF IOUT = 1mA C OUT = Any 40 PSRR (dB) 80 30 20 0 10 100 1k 10k 20 15 10 I OUT = 100mA COUT = 10µF IOUT = Any COUT = 0µF 10 25 Frequency = 100kHz COUT = 10µF VOUT = 2.5V 5 0 100k 1M 0 10M 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 Frequency (Hz) VIN − VOUT (V) Figure 15. Figure 16. NOISE SPECTRAL DENSITY CNR = 0µF NOISE SPECTRAL DENSITY CNR = 0.01µF 1 1.8 2.0 1 COUT = 0µF 0.1 COUT = 10µF eN (µV/√Hz) eN (µV/√Hz) C OUT = 1µF COUT = 1µF 0.1 COUT = 0µF COUT = 10µF I OUT = 150mA I OUT = 150mA 0.01 0.01 10 100 1k 10k 100k 10 100 1k Frequency (Hz) Frequency (Hz) Figure 17. Figure 18. RMS NOISE VOLTAGE vs COUT 10k 100k RMS NOISE VOLTAGE vs CNR 60 140 50 120 VOUT = 5.0V VOUT = 5.0V 100 30 VN (RMS) VN (RMS) 40 VOUT = 3.3V 20 10 0.1 8 20 CNR = 0.01µF 10Hz < Frequency < 100kHz 0 1 10 VOUT = 3.3V 60 40 VOUT = 1.5V 0 80 VOUT = 1.5V COUT = 0µF 10Hz < Frequency < 100kHz 1p 10p 100p COUT (µF) CNR (F) Figure 19. Figure 20. 1n 10n TPS73101, TPS73115, TPS73118 TPS73125, TPS73130, TPS73132 TPS73133, TPS73150 www.ti.com SBVS034E – SEPTEMBER 2003 – REVISED SEPTEMBER 2004 TYPICAL CHARACTERISTICS (continued) For all voltage versions at TJ= 25°C, VIN = VOUT(nom) + 0.5V, IOUT = 10mA, VEN = 1.7V, and COUT = 0.1µF, unless otherwise noted. TPS73133 LOAD TRANSIENT RESPONSE VIN = 3.8V TPS73133 LINE TRANSIENT RESPONSE COUT = 0µF 40mV/tick IOUT = 150mA VOUT COUT = 0µF 50mV/div COUT = 1µF 40mV/tick COUT = 10µF 40mV/tick VOUT VOUT VOUT COUT = 100µF 50mV/div IOUT 25mA/tick 10mA 4.5V 1V/div VIN 10µs/div Figure 21. Figure 22. TPS73133 TURN-ON RESPONSE TPS73133 TURN-OFF RESPONSE RL = 20Ω COUT = 10µF VOUT RL = 20Ω CO UT = 1µF = 0.5V/µs dt 10µs/div RL = 1kΩ COUT = 0µF R L = 20Ω C OUT = 1µF 1V/div RL = 1kΩ COUT = 0µF RL = 20Ω COUT = 10µF VOUT 2V 2V VEN 1V/div 1V/div 0V 0V VEN 100µs/div 100µs/div Figure 23. Figure 24. TPS73133 POWER UP / POWER DOWN IENABLE vs TEMPERATURE 10 6 5 4 VIN VOUT IENABLE (nA) 3 Volts dVIN 5.5V 150mA 1V/div VOUT 2 1 1 0.1 0 −1 −2 50ms/div 0.01 −50 −25 0 25 50 75 100 125 Temperature (C) Figure 25. Figure 26. 9 TPS73101, TPS73115, TPS73118 TPS73125, TPS73130, TPS73132 TPS73133, TPS73150 www.ti.com SBVS034E – SEPTEMBER 2003 – REVISED SEPTEMBER 2004 TYPICAL CHARACTERISTICS (continued) For all voltage versions at TJ= 25°C, VIN = VOUT(nom) + 0.5V, IOUT = 10mA, VEN = 1.7V, and COUT = 0.1µF, unless otherwise noted. TPS73101 IFBvs TEMPERATURE 60 160 55 140 50 120 45 100 IFB (nA) VN (rms) TPS73101 RMS NOISE VOLTAGE vs CADJ 40 35 30 25 80 60 VOUT = 2.5V COUT = 0µF R1 = 39.2kΩ 10Hz < Frequency < 100kHz 20 10p 100p 40 20 1n 10n 0 −50 −25 0 25 50 75 100 CFB (F) Temperature (C) Figure 27. Figure 28. TPS73101 LOAD TRANSIENT, ADJUSTABLE VERSION TPS73101 LINE TRANSIENT, ADJUSTABLE VERSION CFB = 10nF R1 = 39.2kΩ COUT = 0µF 50mV/div VOUT COUT = 0µF 100mV/div COUT = 10µF 100mV/div COUT = 10µF 50mV/div 125 VOUT = 2.5V CFB = 10nF VOUT VOUT VOUT 4.5V 150mA 3.5V VIN 10mA 25µs/div Figure 29. 10 IOUT 5µs/div Figure 30. TPS73101, TPS73115, TPS73118 TPS73125, TPS73130, TPS73132 TPS73133, TPS73150 www.ti.com SBVS034E – SEPTEMBER 2003 – REVISED SEPTEMBER 2004 APPLICATION INFORMATION The TPS731xx belongs to a family of new generation LDO regulators that use an NMOS pass transistor to achieve ultra-low-dropout performance, reverse current blockage, and freedom from output capacitor constraints. These features, combined with low noise and an enable input, make the TPS731xx ideal for portable applications. This regulator family offers a wide selection of fixed output voltage versions and an adjustable output version. All versions have thermal and over-current protection, including foldback current limit. Figure 31 shows the basic circuit connections for the fixed voltage models. Figure 32 gives the connections for the adjustable output version (TPS73101). Optional input capacitor. May improve source impedance, noise, or PSRR. VIN Optional output capacitor. May improve load transient, noise, or PSRR. IN VOUT OUT TPS731xx EN GND NR Figure 31. Typical Application Circuit for Fixed-Voltage Versions VIN Optional output capacitor. May improve load transient, noise, or PSRR. IN EN VOUT OUT TPS731xx GND R1 CFB FB R2 VOUT = (R1 + R2) R2 × 1.204 Although an input capacitor is not required for stability, it is good analog design practice to connect a 0.1µF to 1µF low ESR capacitor across the input supply near the regulator. This counteracts reactive input sources and improves transient response, noise rejection, and ripple rejection. A higher-value capacitor may be necessary if large, fast rise-time load transients are anticipated or the device is located several inches from the power source. The TPS731xx does not require an output capacitor for stability and has maximum phase margin with no capacitor. It is designed to be stable for all available types and values of capacitors. In applications where VIN - VOUT < 0.5V and multiple low ESR capacitors are in parallel, ringing may occur when the product of COUT and total ESR drops below 50nΩF. Total ESR includes all parasitic resistances, including capacitor ESR and board, socket, and solder joint resistance. In most applications, the sum of capacitor ESR and trace resistance will meet this requirement. OUTPUT NOISE Optional bypass capacitor to reduce output noise. Optional input capacitor. May improve source impedance, noise, or PSRR. INPUT AND OUTPUT CAPACITOR REQUIREMENTS Optional capacitor reduces output noise. Figure 32. Typical Application Circuit for Adjustable-Voltage Versions R1 and R2 can be calculated for any output voltage using the formula shown in Figure 32. Sample resistor values for common output voltages are shown in Figure 2. For best accuracy, make the parallel combination of R1 and R2 approximately 19kΩ. A precision band-gap reference is used to generate the internal reference voltage, VREF. This reference is the dominant noise source within the TPS731xx and it generates approximately 32µVRMS (10Hz to 100kHz) at the reference output (NR). The regulator control loop gains up the reference noise with the same gain as the reference voltage, so that the noise voltage of the regulator is approximately given by: V (R R2) V N 32VRMS 1 32VRMS OUT R2 VREF (1) Since the value of VREF is 1.2V, this relationship reduces to: V RMS V N(VRMS) 27 V OUT(V) V (2) for the case of no CNR. An internal 27kΩ resistor in series with the noise reduction pin (NR) forms a low-pass filter for the voltage reference when an external noise reduction capacitor, CNR, is connected from NR to ground. For CNR = 10nF, the total noise in the 10Hz to 100kHz bandwidth is reduced by a factor of ~3.2, giving the approximate relationship: VV V V N(VRMS) 8.5 RMS (V) OUT (3) for CNR = 10nF. 11 TPS73101, TPS73115, TPS73118 TPS73125, TPS73130, TPS73132 TPS73133, TPS73150 www.ti.com SBVS034E – SEPTEMBER 2003 – REVISED SEPTEMBER 2004 This noise reduction effect is shown as RMS Noise Voltage vs CNR in the Typical Characteristics section. The TPS73101 adjustable version does not have the noise-reduction pin available. However, connecting a feedback capacitor, CFB, from the output to the FB pin will reduce output noise and improve load transient performance. The TPS731xx uses an internal charge pump to develop an internal supply voltage sufficient to drive the gate of the NMOS pass element above VOUT. The charge pump generates ~250µV of switching noise at ~4MHz; however, charge-pump noise contribution is negligible at the output of the regulator for most values of IOUT and COUT. BOARD LAYOUT RECOMMENDATION TO IMPROVE PSRR AND NOISE PERFORMANCE To improve ac performance such as PSRR, output noise, and transient response, it is recommended that the PCB be designed with separate ground planes for VIN and VOUT, with each ground plane connected only at the GND pin of the device. In addition, the ground connection for the bypass capacitor should connect directly to the GND pin of the device. DROPOUT VOLTAGE The TPS731xx uses an NMOS pass transistor to achieve extremely low dropout. When (VIN - VOUT) is less than the dropout voltage (VDO), the NMOS pass device is in its linear region of operation and the input-to-output resistance is the RDS-ON of the NMOS pass element. For large step changes in load current, the TPS731xx requires a larger voltage drop across it to avoid degraded transient response. The boundary of this transient dropout region is approximately twice the dc dropout. Values of VIN - VOUT above this line insure normal transient response. Operating in the transient dropout region can cause an increase in recovery time. The time required to recover from a load transient is a function of the magnitude of the change in load current rate, the rate of change in load current, and the available headroom (VIN to VOUT voltage drop). Under worst-case conditions [full-scale instantaneous load change with (VIN - VOUT) close to dc dropout levels], the TPS731xx can take a couple of hundred microseconds to return to the specified regulation accuracy. TRANSIENT RESPONSE INTERNAL CURRENT LIMIT The TPS731xx internal current limit helps protect the regulator during fault conditions. Foldback current helps to protect the regulator from damage during output short-circuit conditions by reducing current limit when VOUT drops below 0.5V. See Figure 11 in the Typical Characteristics section for a graph of IOUT vs VOUT. SHUTDOWN The Enable pin is active high and is compatible with standard TTL-CMOS levels. VEN below 0.5V (max) turns the regulator off and drops the ground pin current to approximately 10nA. When shutdown capability is not required, the Enable pin can be connected to VIN. When a pull-up resistor is used, and operation down to 1.8V is required, use pull-up resistor values below 50 kΩ. The low open-loop output impedance provided by the NMOS pass element in a voltage follower configuration allows operation without an output capacitor for many applications. As with any regulator, the addition of a capacitor (nominal value 1µF) from the output pin to ground will reduce undershoot magnitude but increase duration. In the adjustable version, the addition of a capacitor, CFB, from the output to the adjust pin will also improve the transient response. The TPS731xx does not have active pull-down when the output is over-voltage. This allows applications that connect higher voltage sources, such as alternate power supplies, to the output. This also results in an output overshoot of several percent if the load current quickly drops to zero when a capacitor is connected to the output. The duration of overshoot can be reduced by adding a load resistor. The overshoot decays at a rate determined by output capacitor COUT and the internal/external load resistance. The rate of decay is given by: (Fixed voltage version) V OUT dVdt C OUT 80k 12 (4) TPS73101, TPS73115, TPS73118 TPS73125, TPS73130, TPS73132 TPS73133, TPS73150 www.ti.com (Adjustable voltage version) VOUT dVdt C OUT 80k (R 1 R 2) SBVS034E – SEPTEMBER 2003 – REVISED SEPTEMBER 2004 (5) REVERSE CURRENT The NMOS pass element of the TPS731xx provides inherent protection against current flow from the output of the regulator to the input when the gate of the pass device is pulled low. To ensure that all charge is removed from the gate of the pass element, the enable pin must be driven low before the input voltage is removed. If this is not done, the pass element may be left on due to stored charge on the gate. After the enable pin is driven low, no bias voltage is needed on any pin for reverse current blocking. Note that reverse current is specified as the current flowing out of the IN pin due to voltage applied on the OUT pin. There will be additional current flowing into the OUT pin due to the 80kΩ internal resistor divider to ground (see Figure 1 and Figure 2). For the TPS73101, reverse current may flow when VFB is more than 1.0V above VIN. THERMAL PROTECTION Thermal protection disables the output when the junction temperature rises to approximately 160°C, allowing the device to cool. When the junction temperature cools to approximately 140°C, the output circuitry is again enabled. Depending on power dissipation, thermal resistance, and ambient temperature, the thermal protection circuit may cycle on and off. This limits the dissipation of the regulator, protecting it from damage due to overheating. Any tendency to activate the thermal protection circuit indicates excessive power dissipation or an inadequate heatsink. For reliable operation, junction temperature should be limited to 125°C maximum. To estimate the margin of safety in a complete design (including heatsink), increase the ambient temperature until the thermal protection is triggered; use worst-case loads and signal conditions. For good reliability, thermal protection should trigger at least 35°C above the maximum expected ambient condition of your application. This produces a worst-case junction temperature of 125°C at the highest expected ambient temperature and worst-case load. The internal protection circuitry of the TPS731xx has been designed to protect against overload conditions. It was not intended to replace proper heatsinking. Continuously running the TPS731xx into thermal shutdown will degrade device reliability. POWER DISSIPATION The ability to remove heat from the die is different for each package type, presenting different considerations in the PCB layout. The PCB area around the device that is free of other components moves the heat from the device to the ambient air. Performance data for JEDEC low- and high-K boards are shown in the Power Dissipation Ratings table. Using heavier copper will increase the effectiveness in removing heat from the device. The addition of plated through-holes to heat-dissipating layers will also improve the heat-sink effectiveness. Power dissipation depends on input voltage and load conditions. Power dissipation is equal to the product of the output current times the voltage drop across the output pass element (VIN to VOUT): P D (VIN VOUT) I OUT (6) Power dissipation can be minimized by using the lowest possible input voltage necessary to assure the required output voltage. Package Mounting Solder pad footprint recommendations for the TPS731xx are presented in Application Bulletin Solder Pad Recommendations for Surface-Mount Devices (AB-132), available from the Texas Instruments web site at www.ti.com. 13 PACKAGE OPTION ADDENDUM www.ti.com 30-Sep-2004 PACKAGING INFORMATION ORDERABLE DEVICE STATUS(1) PACKAGE TYPE PACKAGE DRAWING PINS PACKAGE QTY TPS73101DBVR ACTIVE SOP DBV 5 3000 TPS73101DBVT ACTIVE SOP DBV 5 250 TPS73115DBVR ACTIVE SOP DBV 5 3000 TPS73115DBVT ACTIVE SOP DBV 5 250 TPS73118DBVR ACTIVE SOP DBV 5 3000 TPS73118DBVT ACTIVE SOP DBV 5 250 TPS73125DBVR ACTIVE SOP DBV 5 3000 TPS73125DBVT ACTIVE SOP DBV 5 250 TPS73130DBVR ACTIVE SOP DBV 5 3000 TPS73130DBVT ACTIVE SOP DBV 5 250 TPS73132DBVR ACTIVE SOP DBV 5 3000 TPS73132DBVT ACTIVE SOP DBV 5 250 TPS73133DBVR ACTIVE SOP DBV 5 3000 TPS73133DBVT ACTIVE SOP DBV 5 250 TPS73150DBVR ACTIVE SOP DBV 5 3000 TPS73150DBVT ACTIVE SOP DBV 5 250 (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. 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. All products are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment. 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