TPS74301 TP S 743 01 TP S7 43 01 www.ti.com SBVS065E – DECEMBER 2005 – REVISED MAY 2007 1.5A Ultra-LDO with Programmable Sequencing FEATURES • • • • • • • • • • Track Pin Allows for Flexible Power-Up Sequencing 1% Accuracy Over Line, Load, and Temperature Supports Input Voltages as Low as 0.9V with External Bias Supply Adjustable Output (0.8V to 3.6V) Ultra-Low Dropout: 55mV at 1.5A (typ) Stable with Any or No Output Capacitor Excellent Transient Response Available in 5mm × 5mm × 1mm QFN and DDPAK-7 Packages Open-Drain Power-Good (5 × 5 QFN) Active High Enable APPLICATIONS • • • • FPGA Applications DSP Core and I/O Voltages Post-Regulation Applications Applications with Special Start-Up Time or Sequencing Requirements DESCRIPTION The TPS74301 low-dropout (LDO) linear regulator provides an easy-to-use robust power management solution for a wide variety of applications. The TRACK pin allows the output to track an external supply. This feature is useful in minimizing the stress on ESD structures that are present between the CORE and I/O power pins of many processors. The enable input and power-good output allow easy sequencing with external regulators. This complete flexibility allows the user to configure a solution that meets the sequencing requirements of FPGAs, DSPs, and other applications with special start-up requirements. A precision reference and error amplifier deliver 1% accuracy over load, line, temperature, and process. Each LDO is stable with low-cost ceramic output capacitors and the device is fully specified from –40°C to +125°C. The TPS74301 is offered in a small (5mm × 5mm) QFN package, yielding a highly compact total solution size. For applications that require additional power dissipation, the DDPAK (KTW) package is also available. IOUT = 500mA VIN IN R5 EN VBIAS VPG PG TPS74301 CBIAS BIAS R1 VTRACK R3 FB TRACK GND VTRACK VPG VOUT OUT COUT 500mV/div CIN R2 R4 Optional Figure 1. Typical Application Circuit VOUT Time (20ms/div) Figure 2. Tracking Response 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. All trademarks are the property of their respective owners. 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 © 2005–2007, Texas Instruments Incorporated TPS74301 www.ti.com SBVS065E – DECEMBER 2005 – REVISED MAY 2007 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) VOUT (2) PRODUCT TPS743xxyyyz (1) (2) (3) XX is nominal output voltage (for example, 12 = 1.2V, 15 = 1.5V, 01 = Adjustable). (3) YYY is package designator. Z is package quantity. For the most current package and ordering information see the Package Option Addendum at the end of this document, or see the TI website at www.ti.com. Output voltages from 0.9V to 1.5V in 50mV increments and 1.5V to 3.3V in 100mV increments are available through the use of innovative factory EEPROM programming; minimum order quantities may apply. Contact factory for details and availability. For fixed 0.8V operation, tie FB to OUT. ABSOLUTE MAXIMUM RATINGS (1) At TJ = –40°C to +125°C, unless otherwise noted. All voltages are with respect to GND. TPS74301 UNIT –0.3 to +6 V VEN Enable voltage range –0.3 to +6 V VPG Power-good voltage range –0.3 to +6 V 0 to +1.5 mA –0.3 to +6 V –0.3 to +6 V –0.3 to VIN + 0.3 V VIN, VBIAS Input voltage range IPG PG sink current VTRACK Track pin voltage range VFB Feedback pin voltage range VOUT Output voltage range IOUT Maximum output current Internally limited Output short circuit duration Indefinite PDISS Continuous total power dissipation See Dissipation Ratings Table TJ Operating junction temperature range TSTG Storage junction temperature range (1) –40 to +125 °C –55 to +150 °C 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 conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. DISSIPATION RATINGS PACKAGE θJA θJC TA < +25°C POWER RATING DERATING FACTOR ABOVE TA = +25°C RGW (QFN) (1) 36.5°C/W 4.05°C/W 2.74W 27.4mW/°C 18.8°C/W 2.32°C/W 5.32W 53.2mW/°C KTW (1) (2) 2 (DDPAK) (2) See Figure 31 for PCB layout description. See Figure 34 for PCB layout description. Submit Documentation Feedback TPS74301 www.ti.com SBVS065E – DECEMBER 2005 – REVISED MAY 2007 ELECTRICAL CHARACTERISTICS At VEN = 1.1V, VIN = VOUT + 0.3V, CIN = CBIAS = 0.1µF, COUT = 10µF, IOUT = 50mA, VBIAS = 5.0V, and TJ = –40°C to +125°C, unless otherwise noted. Typical values are at TJ = +25°C. TPS74301 PARAMETER MAX UNIT VIN Input voltage range VOUT + VDO 5.5 V VBIAS Bias pin voltage range 2.375 5.25 V 0.804 V VREF Internal reference (Adj.) VOUT TJ = +25°C 0.796 VIN = 5V, IOUT = 1.5A, VBIAS = 5V VREF Accuracy (1) 2.375V ≤ VBIAS ≤ 5.25V, 50mA ≤ IOUT ≤ 1.5A VOUT/IOUT Load regulation VIN dropout voltage (2) VBIAS dropout voltage (2) ICL Current limit IBIAS Bias pin current ISHDN Shutdown supply current (VIN) IFB Feedback pin current (3) PSRR V ±0.2 1 % VOUT (NOM) + 0.3 ≤ VIN ≤ 5.5V, QFN 0.0005 0.05 VOUT (NOM) + 0.3 ≤ VIN ≤ 5.5V, DDPAK 0.0005 0.06 0mA ≤ IOUT ≤ 50mA 0.013 50mA ≤ IOUT ≤ 1.5A 0.04 100 IOUT = 1.5A, VBIAS – VOUT (NOM) ≥ 1.62V, DDPAK 60 120 VOUT = 80% × VOUT (NOM) 1.4 V 4 A 2 4 mA VEN ≤ 0.4V 1 100 µA 68 250 nA IOUT = 50mA to 1.5A 1.8 mV IOUT = 0mA to 1.5A –250 42 Power-supply rejection (VBIAS to VOUT) 1kHz, IOUT = 1.5A, VIN = 1.8V, VOUT = 1.5V 67 800kHz, IOUT = 1.5A, VIN = 1.8V, VOUT = 1.5V 50 %VOUT droop during load transient %/A 55 IOUT = 1.5A, VIN = VBIAS %/V %/mA IOUT = 1.5A, VBIAS – VOUT (NOM) ≥ 1.62V, QFN 800kHz, IOUT = 1.5A, VIN = 1.8V, VOUT = 1.5V ITR Track pin current dB dB 25 × VOUT µVRMS IOUT = 50mA to 1.5A at 1A/µs, COUT = none 3.5 %VOUT VTRACK > 0.8V 40 µs 100Hz to 100kHz, IOUT = 1.5A 0.2V ≤ VTRACK≤ 0.7V, VOUT = 0.8V –60 VTRACK = 0.4V 0.1 60 mV 1 µA HI Enable input high level 1.1 5.5 V LO Enable input low level 0 0.4 V HYS Enable pin hysteresis 50 Enable pin deglitch time 20 VEN, VEN, DG IEN Enable pin current VEN = 5V VIT PG trip threshold VOUT decreasing 86.5 VHYS PG trip hysteresis (1) (2) (3) 3.6 Power-supply rejection (VIN to VOUT) TACC Track pin accuracy VEN, 0.8 73 tSTR Minimum startup time VEN, –1 TYP 1kHz, IOUT = 1.5A, VIN = 1.8V, VOUT = 1.5V Noise Output noise voltage VTRAN MIN Output voltage range VOUT/VIN Line regulation VDO TEST CONDITIONS IPG = 1mA (sinking), VOUT < VIT IPG, LKG PG leakage current VPG = 5.25V, VOUT > VIT TJ TSD Thermal shutdown temperature µs 0.1 1 µA 90 93.5 %VOUT 3 VPG, LO PG output low voltage Operating junction temperature mV 0.3 –40 Shutdown, temperature increasing +155 Reset, temperature decreasing +140 %VOUT 0.3 V 1 µA +125 °C °C Adjustable devices tested at 0.8V; external resistor tolerance is not taken into account. Dropout is defined as the voltage from the input to VOUT when VOUT is 2% below nominal. IFB current flow is out of the device. Submit Documentation Feedback 3 TPS74301 www.ti.com SBVS065E – DECEMBER 2005 – REVISED MAY 2007 BLOCK DIAGRAM Current Limit IN BIAS VOUT UVLO Thermal Limit VTRACK < VREF = 1, VTRACK > VREF = 0 R1 1 TRACK 0 VOUT = 0.8 x (1 + 0.8V Reference FB PG EN Hysteresis and De-Glitch R2 0.9 ´ VREF GND Table 1. Standard 1% Resistor Values for Programming the Output Voltage (1) (1) 4 R1 (kΩ) R2 (kΩ) VOUT (V) Short Open 0.8 0.619 4.99 0.9 1.13 4.53 1.0 1.37 4.42 1.05 1.87 4.99 1.1 2.49 4.99 1.2 4.12 4.75 1.5 3.57 2.87 1.8 3.57 1.69 2.5 3.57 1.15 3.3 VOUT = 0.8 × (1 + R1/R2) Submit Documentation Feedback R1 ) R2 TPS74301 www.ti.com SBVS065E – DECEMBER 2005 – REVISED MAY 2007 IN NC NC NC OUT 5 4 3 2 1 5 ´ 5 QFN (RGW) Package ¾ Top View 7-Lead DDPAK (KTW) Surface-Mount IN 6 20 OUT IN 7 19 OUT IN 8 18 OUT PG 9 17 NC BIAS 10 16 FB 11 12 13 14 15 EN GND NC NC TRACK TPS74301 1 2 3 4 5 6 7 TRACK OUT IN EN FB GND BIAS PIN DESCRIPTIONS NAME KTW (DDPAK) RGW (QFN) DESCRIPTION IN 5 5–8 Unregulated input to the device. EN 7 11 Enable pin. Driving this pin high enables the regulator. Driving this pin low puts the regulator into shutdown mode. This pin must not be left floating. TRACK 1 15 Tracking pin. Connect this pin to the center tap of a resistor divider off of an external supply to program the device to track an external supply. BIAS 6 10 Bias input voltage for error amplifier, reference, and internal control circuits. PG N/A 9 Power-Good (PG) is an open-drain, active-high output that indicates the status of VOUT. When VOUT exceeds the PG trip threshold, the PG pin goes into a high-impedance state. When VOUT is below this threshold the pin is driven to a low-impedance state. A pull-up resistor from 10kΩ to 1MΩ should be connected from this pin to a supply up to 5.5V. The supply can be higher than the input voltage. Alternatively, the PG pin can be left floating if output monitoring is not necessary. FB 2 16 This pin is the feedback connection to the center tap of an external resistor divider network that sets the output voltage. This pin must not be left floating. OUT 3 1, 18–20 NC N/A 2–4, 13, 14, 17 GND 4 12 PAD/TAB Regulated output voltage. No capacitor is required on this pin for stability. No connection. This pin can be left floating or connected to GND to allow better thermal contact to the top-side plane. Ground Should be soldered to the ground plane for increased thermal performance. Submit Documentation Feedback 5 TPS74301 www.ti.com SBVS065E – DECEMBER 2005 – REVISED MAY 2007 TYPICAL CHARACTERISTICS At TJ = +25°C, VOUT = 1.5V, VIN = VOUT(TYP) + 0.3V, VBIAS = 3.3V, IOUT = 50mA, EN = VIN, CIN = 1µF, CBIAS = 4.7µF, and COUT = 10µF, unless otherwise noted. LOAD REGULATION 1.0 LOAD REGULATION 0.050 Referred to IOUT = 50mA 0.9 Referred to IOUT = 50mA 0.025 0.7 0.6 -40°C 0.5 0.4 +25°C 0.3 0.2 0.1 0 Change in VOUT (%) Change in VOUT (%) 0.8 -0.050 -40°C -0.075 +125°C -0.100 +125°C 0 +25°C -0.025 -0.125 -0.1 -0.150 0 10 20 30 40 50 50 500 1000 1500 IOUT (mA) IOUT (mA) Figure 3. Figure 4. LINE REGULATION VIN DROPOUT VOLTAGE vs IOUT AND TEMPERATURE (TJ) 0.05 100 0.04 0.02 Dropout Voltage (mV) Change in VOUT (%) 0.03 TJ = -40°C 0.01 0 -0.01 TJ = +25°C TJ = +125°C -0.02 -0.03 75 +125°C 50 +25°C 25 -40°C -0.04 0 -0.05 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 0 0.5 VIN - VOUT (V) Figure 6. VIN DROPOUT VOLTAGE vs VBIAS – VOUT AND TEMPERATURE (TJ) VIN DROPOUT VOLTAGE vs VBIAS – VOUT AND TEMPERATURE (TJ) 60 IOUT = 1.5A 180 IOUT = 500mA 50 Dropout Voltage (mV) 160 Dropout Voltage (mV) 1.5 Figure 5. 200 140 120 +125°C 100 +25°C 80 60 40 40 +125°C 30 +25°C 20 10 -40°C 20 -40°C 0 0 0.9 1.4 1.9 2.4 2.9 3.4 3.9 0.9 VBIAS - VOUT (V) 1.4 1.9 2.4 2.9 VBIAS - VOUT (V) Figure 7. 6 1.0 IOUT (A) Figure 8. Submit Documentation Feedback 3.4 3.9 TPS74301 www.ti.com SBVS065E – DECEMBER 2005 – REVISED MAY 2007 TYPICAL CHARACTERISTICS (continued) At TJ = +25°C, VOUT = 1.5V, VIN = VOUT(TYP) + 0.3V, VBIAS = 3.3V, IOUT = 50mA, EN = VIN, CIN = 1µF, CBIAS = 4.7µF, and COUT = 10µF, unless otherwise noted. VBIAS PSRR vs FREQUENCY 1400 90 1300 80 1200 +25°C +125°C 1100 Power-Supply Rejection (dB) Dropout Voltage (mV) VBIAS DROPOUT VOLTAGE vs IOUT AND TEMPERATURE 1000 -40°C 900 800 700 IOUT = 1.5A 70 60 50 40 30 20 10 600 0 500 50 500 1000 1500 10 100 Figure 10. 60 50 40 30 20 COUT = 0mF 10 Power-Supply Rejection Ratio (dB) Power-Supply Rejection Ratio (dB) COUT = 100mF C OUT = 10mF 70 100 1k 10k 100k 80 70 COUT = 100mF 60 COUT = 10mF 50 40 30 20 10 COUT = 0mF 1M 10 10M 100 Figure 11. Figure 12. 700kHz 60 50 300kHz 100kHz 20 10 IOUT = 1.5A 0 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 Output Spectral Noise Density (mV/ÖHz) 1kHz 40 100k 1M 10M NOISE SPECTRAL DENSITY 80 0 10k Frequency (Hz) VIN PSRR vs VIN – VOUT 30 1k Frequency (Hz) 90 70 10M VIN = 1.8, VOUT = 1.5V, IOUT = 1.5A 90 0 0 10 1M VIN PSRR vs FREQUENCY VIN = 1.8, VOUT = 1.5V, IOUT = 100mA 80 100k Figure 9. 100 90 10k Frequency (Hz) VIN PSRR vs FREQUENCY 100 Power-Supply Rejection Ratio (dB) 1k IOUT (mA) 1 IOUT = 1.5A VOUT = 1.1V 0.1 0.01 100 VIN - VOUT (V) 1k 10k 100k Frequency (Hz) Figure 13. Figure 14. Submit Documentation Feedback 7 TPS74301 www.ti.com SBVS065E – DECEMBER 2005 – REVISED MAY 2007 TYPICAL CHARACTERISTICS (continued) At TJ = +25°C, VOUT = 1.5V, VIN = VOUT(TYP) + 0.3V, VBIAS = 3.3V, IOUT = 50mA, EN = VIN, CIN = 1µF, CBIAS = 4.7µF, and COUT = 10µF, unless otherwise noted. VBIAS LINE TRANSIENT VIN LINE TRANSIENT (1.5A) 20mV/div COUT = 2 x 470mF (OSCON) 20mV/div COUT = 100mF (Cer.) 10mV/div COUT = 2 x 470mF (OSCON) VOUT = 1.2V COUT = 100mF (Cer.) 10mV/div 10mV/div COUT = 10mF (Cer.) COUT = 10mF (Cer.) 20mV/div COUT = 0mF 10mV/div COUT = 0mF 20mV/div 2.5V 4.3V 4.3V 1V/div 1V/ms 500mV/div 1V/ms 3.3V 1.5V Time (50ms/div) Time (50ms/div) Figure 15. Figure 16. OUTPUT LOAD TRANSIENT RESPONSE TRACKING RESPONSE COUT = 2 x 470mF (OSCON) IOUT = 500mA 50mV/div COUT = 100mF (Cer.) 50mV/div VTRACK 50mV/div 500mV/div VPG COUT = 10mF (Cer.) COUT = 0mF 50mV/div VOUT 1.5A 1A/ms 1A/div 50mA Time (50ms/div) Time (20ms/div) Figure 17. Figure 18. POWER-UP/POWER-DOWN IBIAS vs IOUT AND TEMPERATURE 2.85 VIN = VBIAS = VEN VPG (500mV/div) VOUT Bias Current (mA) 1V/div 2.65 +125°C 2.45 2.25 2.05 +25°C 1.85 1.65 -40°C 1.45 1.25 Time (20ms/div) 0 0.5 1.0 IOUT (A) Figure 19. 8 Figure 20. Submit Documentation Feedback 1.5 TPS74301 www.ti.com SBVS065E – DECEMBER 2005 – REVISED MAY 2007 TYPICAL CHARACTERISTICS (continued) At TJ = +25°C, VOUT = 1.5V, VIN = VOUT(TYP) + 0.3V, VBIAS = 3.3V, IOUT = 50mA, EN = VIN, CIN = 1µF, CBIAS = 4.7µF, and COUT = 10µF, unless otherwise noted. IBIAS vs VBIAS AND VOUT IBIAS SHUTDOWN vs TEMPERATURE 3.0 0.45 2.8 2.4 2.2 +25°C 2.0 1.8 1.6 -40°C 1.4 VBIAS = 2.375V 0.35 Bias Current (mA) Bias Current (mA) 0.40 +125°C 2.6 0.30 VBIAS = 5.5V 0.25 0.20 0.15 0.10 0.05 1.2 1.0 0 2.0 2.5 3.0 3.5 4.0 4.5 5.0 -40 0 -20 VBIAS (V) 20 40 60 80 100 120 Junction Temperature (°C) Figure 21. Figure 22. TURN-ON RESPONSE–QFN PACKAGE LOW-LEVEL PG VOLTAGE vs PG CURRENT VTRACK = VIN IOUT = 1.5A VOUT 1V/div 1.1V 1V/div 0V VEN VOL Low-Level PG Voltage (V) 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 Time (50ms/div) 0 2 6 4 8 10 12 PG Current (mA) Figure 23. Figure 24. OUTPUT SHORT-CIRCUIT RECOVERY IOUT 500mA/div VOUT 50mV/div Output Shorted Output Open Time (20ms/div) Figure 25. Submit Documentation Feedback 9 TPS74301 www.ti.com SBVS065E – DECEMBER 2005 – REVISED MAY 2007 APPLICATION INFORMATION The TPS74301 belongs to a family of new generation ultra-low dropout regulators that feature soft-start and tracking capabilities. These regulators use a low current bias input to power all internal control circuitry, allowing the NMOS pass transistor to regulate very low input and output voltages. Figure 26 is a typical application circuit for the TPS74301 adjustable device. R1 and R2 can be calculated for any output voltage using the formula shown in Figure 26. Refer to Table 1 for sample resistor values of common output voltages. In order to achieve the maximum accuracy specifications, R2 should be ≤ 4.99kΩ. The use of an NMOS-pass FET offers several critical advantages for many applications. Unlike a PMOS topology device, the output capacitor has little effect on loop stability. This architecture allows the TPS74301 to be stable with any or even no output capacitor. Transient response is also superior to PMOS topologies, particularly for low VIN applications. INPUT, OUTPUT, AND BIAS CAPACITOR REQUIREMENTS The device does not require any output capacitor for stability. If an output capacitor is needed, the device is designed to be stable for all available types and values of output capacitance. The device is also stable with multiple capacitors in parallel, of any type or value. The TPS74301 features a TRACK pin that allows the output to track an external supply. This feature is useful in minimizing the stress on ESD structures that are present between the CORE and I/O power pins of many processors. A power-good (PG) output is also available to allow supply monitoring and sequencing of follow-on supplies. To control the output turn-on, an enable (EN) pin with hysteresis and deglitch is provided to allow slow-ramping signals to be utilized for sequencing the device. The low VIN and VOUT capability allows for inexpensive, easy-to-design, and efficient linear regulation between the multiple supply voltages often present in processor intensive systems. The capacitance required on the IN and BIAS pins is strongly dependent on the input supply source impedance. To counteract any inductance in the input, the minimum recommended capacitor for VIN and VBIAS is 1µF. If VIN and VBIAS are connected to the same supply, the recommended minimum capacitor for VBIAS is 4.7µF. Good quality, low ESR capacitors should be used on the input; ceramic X5R and X7R capacitors are preferred. These capacitors should be placed as close the pins as possible for optimum performance. VIN CIN IN PG TPS74301 R5 EN VBIAS VPG VOUT OUT CBIAS BIAS R1 VTRACK R3 FB TRACK COUT Optional GND R2 R4 VOUT = 0.8 ´ ( 1+ R1 R2 ) Figure 26. Typical Application Circuit for the TPS74301 (Adjustable) 10 Submit Documentation Feedback TPS74301 www.ti.com SBVS065E – DECEMBER 2005 – REVISED MAY 2007 TRANSIENT RESPONSE IN BIAS The TPS74301 was designed to have transient response within 5% for most applications without any output capacitor. In some cases, the transient response may be limited by the transient response of the input supply. This limitation is especially true in applications where the difference between the input and output is less than 300mV. In this case, adding additional input capacitance improves the transient response much more than just adding additional output capacitance would do. With a solid input supply, adding additional output capacitance reduces undershoot and overshoot during a transient at the expense of a slightly longer VOUT recovery time. Refer to Figure 17 in the Typical Characteristics section. Since the TPS74301 is stable without an output capacitor, many applications may allow for little or no capacitance at the LDO output. For these applications, local bypass capacitance for the device under power may be sufficient to meet the transient requirements of the application. This design reduces the total solution cost by avoiding the need to use expensive high-value capacitors at the LDO output. DROPOUT VOLTAGE The TPS74301 offers industry-leading dropout performance, making it well-suited for high-current low VIN/low VOUT applications. The extremely low dropout of the TPS74301 allows the device to be used instead of a DC/DC converter and still achieve good efficiencies. This efficiency allows users to rethink the power architecture for their applications to find the smallest, simplest, and lowest cost solution. Reference VBIAS = 5V ± 5% VIN = 1.8V VOUT = 1.5V IOUT = 1.5A Efficiency = 83% OUT FB Simplified Block Diagram Figure 27. Typical Application of the TPS74301 Using an Auxiliary Bias Rail The second specification (see Figure 28), referred to as VBIAS Dropout, is for users who wish to tie IN and BIAS together. This option allows the device to be used in applications where an auxiliary bias voltage is unavailable or low dropout is not required. Dropout is limited by BIAS in these applications because VBIAS provides the gate drive to the pass FET, and therefore must be 1.4V above VOUT. VIN BIAS Reference IN VBIAS = 3.3V ± 5% VIN = 3.3V ± 5% VOUT = 1.5V IOUT = 1.5A Efficiency = 45% OUT There are two different specifications for dropout voltage with the TPS74301. The first specification (as shown in Figure 27) is referred to as VIN Dropout and is for users wishing to apply an external bias voltage to achieve low dropout. This specification assumes that VBIAS is at least 1.62V above VOUT, which is the case for VBIAS when powered by a 3.3V rail with 5% tolerance and with VOUT = 1.5V. If VBIAS is higher than 3.3V × 0.95 or VOUT is less than 1.5V, VIN dropout is less than specified. VOUT VOUT FB Simplified Block Diagram Figure 28. Typical Application of the TPS74301 Without an Auxiliary Bias Submit Documentation Feedback 11 TPS74301 www.ti.com SBVS065E – DECEMBER 2005 – REVISED MAY 2007 PROGRAMMABLE SEQUENCING WITH TRACK The TPS74301 features a track pin that allows the output to track an external supply at start-up. While the TRACK input is below 0.8V, the error amplifier regulates the FB pin to the TRACK input. Properly choosing the resistor divider network (R1 and R2) as shown in Figure 29 enables the regulator output to track the external supply to obtain a simultaneous or ratiometric start-up. Once the TRACK input reaches 0.8V, the error amplifier regulates the FB pin to the 0.8V internal reference. Further increases to the TRACK input have no effect. TPS74201 LDO1 IN 5V R3 32.4kW (1) OUT BIAS PG EN SS DSP 3.3V I/O R1 R4 10kW R2 TPS74301 LDO2 OUT IN BIAS EN (1) 1.2V CORE The device can have VIN, VBIAS, VEN, and VTRACK sequenced in any order without causing damage to the device. However, for the track function to work as intended, certain sequencing rules must be applied. VBIAS must be present and the device enabled before the track signal starts to ramp. VIN should ramp up faster than the external supply being tracked so that the tracking signal will not drive the device into VIN dropout as VOUT ramps up. The preferred method to sequence the tracking device is to have VIN, VBIAS, and VEN above the minimum required voltages before enabling the master supply to initiate the startup sequence. This method is illustrated in Figure 29. Resistors R3 and R4 disable the master supply until the input voltage is above 3.52V (typical). If the TRACK pin is not needed it should be connected to VIN. Configured in this way, the device starts up typically within 40µs, which may result in large inrush current that could cause the input supply to droop. If soft-start is needed, consider the TPS74201 or TPS74401 devices. PG OUTPUT NOISE TRACK SIMULTANEOUS SEQUENCING I/O CORE R1 = VCCCORE - 0.8 0.8 RATIOMETRIC SEQUENCING VOUT SEQUENCING REQUIREMENTS x R2 (2) I/O CORE R1 = VCCIO - 0.808 0.808 x R2 The TPS74301 provides low output noise when a soft-start capacitor is used. When the device reaches the end of the soft-start cycle, the soft-start capacitor serves as a filter for the internal reference. By using a 0.001µF soft-start capacitor, the output noise is reduced by half and is typically 30µVRMS for a 1.2V output (10Hz to 100kHz). Because most of the output noise is generated by the internal reference, the noise is a function of the set output voltage. The RMS noise with a 0.001µF soft-start capacitor is given in Equation 1. ǒmVV Ǔ V NǒmVRMSǓ + 25 Time NOTES: (1) Capacitors on IN, BIAS, and OUT along with the resistors necessary to set the output voltage have been omitted for simplification. (2) Lowest value for VCORE and highest value for R2 should be used in this calculation. R1 must be the closest standard value below the calculated value for proper ratiometric sequencing. Figure 29. Various Sequencing Methods Using the TRACK Pin The maximum recommended value for R2 is 100kΩ. Once R2 is selected, R1 is calculated using one of the equations given in Figure 29. 12 RMS V OUT(V) (1) The low output noise of the TPS74301 makes it a good choice for powering transceivers, PLLs, or other noise-sensitive circuitry. ENABLE/SHUTDOWN The enable (EN) pin is active high and is compatible with standard digital signaling levels. VEN below 0.4V turns the regulator off, while VEN above 1.1V turns the regulator on. Unlike many regulators, the enable circuitry has hysteresis and deglitching for use with relatively slow-ramping analog signals. This configuration allows the TPS74301 to be enabled by connecting the output of another supply to the EN pin. The enable circuitry typically has 50mV of hysteresis and a deglitch circuit to help avoid on-off cycling because of small glitches in the VEN signal. Submit Documentation Feedback TPS74301 www.ti.com SBVS065E – DECEMBER 2005 – REVISED MAY 2007 The enable threshold is typically 0.8V and varies with temperature and process variations. Temperature variation is approximately –1mV/°C; therefore, process variation accounts for most of the variation in the enable threshold. If precise turn-on timing is required, a fast rise-time signal should be used to enable the TPS74301. If not used, EN can be connected to either IN or BIAS. If EN is connected to IN, it should be connected as close as possible to the largest capacitance on the input to prevent voltage droops on that line from triggering the enable circuit. POWER-GOOD (QFN Package Only) The power-good (PG) pin is an open-drain output and can be connected to any 5.5V or lower rail through an external pull-up resistor. This pin requires at least 1.1V on VBIAS in order to have a valid output. The PG output is high-impedance when VOUT is greater than VIT + VHYS. If VOUT drops below VIT or if VBIAS drops below 1.9V, the open-drain output turns on and pulls the PG output low. The PG pin also asserts when the device is disabled. The recommended operating condition of PG pin sink current is up to 1mA, so the pull-up resistor for PG should be in the range of 10kΩ to 1MΩ. PG is only provided on the QFN package. If output voltage monitoring is not needed, the PG pin can be left floating. INTERNAL CURRENT LIMIT The TPS74301 features a factory-trimmed, accurate current limit that is flat over temperature and supply voltage. The current limit allows the device to supply surges of up to 1.8A and maintain regulation. The current limit responds in about 10µs to reduce the current during a short-circuit fault. Recovery from a short-circuit condition is well-controlled and results in very little output overshoot when the load is removed. See Figure 25 in the Typical Characteristics section for output short-circuit recovery performance. The internal current limit protection circuitry of the TPS74301 is designed to protect against overload conditions. It is not intended to allow operation above the rated current of the device. Continuously running the TPS74301 above the rated current degrades device reliability. THERMAL PROTECTION dissipation, thermal resistance, and ambient temperature the thermal protection circuit may cycle on and off. This cycling limits the dissipation of the regulator, protecting it from damage as a result of overheating. Activation of the thermal protection circuit indicates excessive power dissipation or inadequate heatsinking. 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 thermal protection is triggered; use worst-case loads and signal conditions. For good reliability, thermal protection should trigger at least +30°C above the maximum expected ambient condition of the application. This condition 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 TPS74301 is designed to protect against overload conditions. It is not intended to replace proper heatsinking. Continuously running the TPS74301 into thermal shutdown degrades device reliability. LAYOUT RECOMMENDATIONS AND POWER DISSIPATION An optimal layout can greatly improve transient performance, PSRR, and noise. To minimize the voltage droop on the input of the device during load transients, the capacitance on IN and BIAS should be connected as close as possible to the device. This capacitance also minimizes the effects of parasitic inductance and resistance of the input source and can therefore improve stability. To achieve optimal transient performance and accuracy, the top side of R1 in Figure 26 should be connected as close as possible to the load. If BIAS is connected to IN, it is recommended to connect BIAS as close to the sense point of the input supply as possible. This connection minimizes the voltage droop on BIAS during transient conditions and can improve the turn-on response. Knowing the device power dissipation and proper sizing of the thermal plane that is connected to the tab or pad is critical to avoiding thermal shutdown and ensuring reliable operation. Power dissipation of the device depends on input voltage and load conditions, and can be calculated using Equation 2: P D + ǒVIN * VOUTǓ I OUT (2) Thermal protection disables the output when the junction temperature rises to approximately +155°C, allowing the device to cool. When the junction temperature cools to approximately +140°C, the output circuitry is enabled. Depending on power Submit Documentation Feedback 13 TPS74301 www.ti.com SBVS065E – DECEMBER 2005 – REVISED MAY 2007 Power dissipation can be minimized and greater efficiency can be achieved by using the lowest possible input voltage necessary to achieve the required output voltage regulation. On both the QFN (RGW) and DDPAK (KTW) packages, the primary conduction path for heat is through the exposed pad or tab to the printed circuit board (PCB). The pad or tab can be connected to ground or be left floating; however, it should be attached to an appropriate amount of copper PCB area to ensure the device does not overheat. The maximum junction-to-ambient thermal resistance depends on the maximum ambient temperature, maximum device junction temperature, and power dissipation of the device, and can be calculated using Equation 3: ()125OC * T A) R qJA + PD (3) Knowing the maximum RθJA and system air flow, the minimum amount of PCB copper area needed for appropriate heatsinking can be calculated using Figure 30 through Figure 34. PCB Top View PCB Cross Section TJ RqJC TC RqCS 0.062in. TS RqSA 4-layer. 0.062” FR4 Vias are 0.012” diameter, plated Top/Bottom layers are 2 oz. copper Inner layers are 1 oz. copper 0.5in TA 1.0in RqJA = RqJC + RqCS + RqSA 2.0in 2 2 2 55 50 0 LFM qJA (°C/W) 45 40 150 LFM 35 250 LFM 30 25 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 2 Area (in ) Figure 30. PCB Layout and Corresponding RθJA Data, Buried Thermal Plane, No Vias Under Thermal Pad 14 Submit Documentation Feedback TPS74301 www.ti.com SBVS065E – DECEMBER 2005 – REVISED MAY 2007 PCB Top View PCB Cross Section TJ RqJC TC RqCS 0.062in. TS 0.5in RqSA 4-layer. 0.062” FR4 Vias are 0.012” diameter, plated Top/Bottom layers are 2 oz. copper Inner layers are 1 oz. copper 1.0in TA 2.0in 2 2 2 RqJA = RqJC + RqCS + RqSA 50 45 0 LFM qJA (°C/W) 40 150 LFM 35 30 250 LFM 25 20 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 2 Area (in ) Figure 31. PCB Layout and Corresponding RθJA Data, Buried Thermal Plane, Vias Under Thermal Pad Submit Documentation Feedback 15 TPS74301 www.ti.com SBVS065E – DECEMBER 2005 – REVISED MAY 2007 PCB Top View PCB Cross Section TJ RqJC TC RqCS 0.062in. TS 4-layer. 0.062” FR4 Vias are 0.012” diameter, plated Top/Bottom layers are 2 oz. copper Inner layers are 1 oz. copper 0.5in RqSA 1.0in TA 2.0in 2 2 RqJA = RqJC + RqCS + RqSA 90 80 qJA (°C/W) 70 0 LFM 60 150 LFM 50 40 250 LFM 30 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 2 Area (in ) Figure 32. PCB Layout and Corresponding RθJA Data, Top Layer Thermal Plane 16 Submit Documentation Feedback 2 TPS74301 www.ti.com SBVS065E – DECEMBER 2005 – REVISED MAY 2007 PCB Top View PCB Cross Section 2.0in 2 TJ RqJC 1.0in 2 TC 0.5in RqCS 0.062in. 2 TS RqSA 4-layer. 0.062” FR4 Vias are 0.012” diameter, plated Top/Bottom layers are 2 oz. copper Inner layers are 1 oz. copper TA RqJA = RqJC + RqCS + RqSA 35 0 LFM qJA (°C/W) 30 25 20 15 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 2 Area (in ) Figure 33. PCB Layout and Corresponding RθJA, Buried Thermal Plane Submit Documentation Feedback 17 TPS74301 www.ti.com SBVS065E – DECEMBER 2005 – REVISED MAY 2007 PCB Top View PCB Cross Section 2.0in 2 TJ 1.0in RqJC TC 2 0.5in 2 RqCS 0.062in. TS RqSA 4-layer. 0.062” FR4 Vias are 0.012” diameter, plated Top/Bottom layers are 2 oz. copper Inner layers are 1 oz. copper TA RqJA = RqJC + RqCS + RqSA 55 50 45 qJA (°C/W) 40 35 30 0 LFM 25 20 15 10 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 2 Area (in ) Figure 34. PCB Layout and Corresponding RθJA, Top Layer Thermal Plane 18 Submit Documentation Feedback PACKAGE OPTION ADDENDUM www.ti.com 5-Feb-2007 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Eco Plan (2) Qty TPS74301KTWR ACTIVE DDPAK KTW 7 500 Green (RoHS & no Sb/Br) CU SN Level-3-245C-168 HR TPS74301KTWRG3 ACTIVE DDPAK KTW 7 500 Green (RoHS & no Sb/Br) CU SN Level-3-245C-168 HR TPS74301KTWT ACTIVE DDPAK KTW 7 50 Green (RoHS & no Sb/Br) CU SN Level-3-245C-168 HR TPS74301KTWTG3 ACTIVE DDPAK KTW 7 50 Green (RoHS & no Sb/Br) CU SN Level-3-245C-168 HR TPS74301RGWR ACTIVE QFN RGW 20 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR TPS74301RGWRG4 ACTIVE QFN RGW 20 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR TPS74301RGWT ACTIVE QFN RGW 20 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR TPS74301RGWTG4 ACTIVE QFN RGW 20 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR Lead/Ball Finish MSL Peak Temp (3) (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. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 17-May-2007 TAPE AND REEL INFORMATION Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com Device 17-May-2007 Package Pins Site Reel Diameter (mm) Reel Width (mm) A0 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant TPS74301RGWR RGW 20 MLA 330 12 5.3 5.3 1.5 8 12 PKGORN T2TR-MS P TPS74301RGWT RGW 20 MLA 180 12 5.3 5.3 1.5 8 12 PKGORN T2TR-MS P TAPE AND REEL BOX INFORMATION Device Package Pins Site Length (mm) Width (mm) TPS74301RGWR RGW 20 MLA 346.0 346.0 29.0 TPS74301RGWT RGW 20 MLA 190.0 212.7 31.75 Pack Materials-Page 2 Height (mm) PACKAGE MATERIALS INFORMATION www.ti.com 17-May-2007 Pack Materials-Page 3 MECHANICAL DATA MPSF015 – AUGUST 2001 KTW (R-PSFM-G7) PLASTIC FLANGE-MOUNT 0.410 (10,41) 0.385 (9,78) 0.304 (7,72) –A– 0.006 –B– 0.303 (7,70) 0.297 (7,54) 0.0625 (1,587) H 0.055 (1,40) 0.0585 (1,485) 0.300 (7,62) 0.064 (1,63) 0.045 (1,14) 0.252 (6,40) 0.056 (1,42) 0.187 (4,75) 0.370 (9,40) 0.179 (4,55) 0.330 (8,38) H 0.296 (7,52) A 0.605 (15,37) 0.595 (15,11) 0.012 (0,305) C 0.000 (0,00) 0.019 (0,48) 0.104 (2,64) 0.096 (2,44) H 0.017 (0,43) 0.050 (1,27) C C F 0.034 (0,86) 0.022 (0,57) 0.010 (0,25) M B 0.026 (0,66) 0.014 (0,36) 0°~3° AM C M 0.183 (4,65) 0.170 (4,32) 4201284/A 08/01 NOTES: A. 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