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TPS50601MHKHV

TPS50601MHKHV

  • 厂商:

    BURR-BROWN(德州仪器)

  • 封装:

    CFP20

  • 描述:

    IC REG BUCK ADJUSTABLE 6A 20CFP

  • 数据手册
  • 价格&库存
TPS50601MHKHV 数据手册
Sample & Buy Product Folder Support & Community Tools & Software Technical Documents Reference Design TPS50601-SP SLVSD45 – DECEMBER 2015 TPS50601-SP Radiation Hardened 1.6- to 6.3-V Input, 6-A Synchronous Buck Converter 1 Features 2 Applications • • 1 • • • • • • • • • • • • • • • 5962R10221: – Radiation Hardness Assurance (RHA) up to TID 100 krad (Si) – ELDRS Free 100 krad (Si) – 10 mRAD(Si)/s – Single Event Latchup (SEL) Immune to LET = 85 MeV-cm2/mg (See Radiation Report) – SEB and SEGR Immune to 85 MeV-cm2/mg, SOA Curve Available (See Radiation Report) – SET/SEFI Cross-Section Plot Available (See Radiation Report) Peak Efficiency: 95% (VO = 3.3 V) Integrated 55-mΩ/50-mΩ MOSFETs Split Power Rail: 1.6 to 6.3 V on PVIN Power Rail: 3 to 6.3 V on VIN 6-A Maximum Output Current Flexible Switching Frequency Options: – 100-kHz to 1-MHz Adjustable Internal Oscillator – External Sync Capability: 100 kHz to 1 MHz – Sync Pin can be Configured as a 500-kHz Output for Master/Slave Applications 0.795-V ±1.258% Voltage Reference at 25°C Monotonic Start-Up into Prebiased Outputs Adjustable Soft Start Through External Capacitor Input Enable and Power-Good Output for Power Sequencing Power Good Output Monitor for Undervoltage and Overvoltage Adjustable Input Undervoltage Lockout (UVLO) 20-Pin Thermally-Enhanced Ceramic Flatpack Package (HKH) See www.ti.com/swift for SWIFT™ Documentation See the Tools & Software Tab • • • • Space Satellite Point of Load Supply for FPGAs, Microcontrollers, and ASICs Space Satellite Payloads Radiation-Tolerant Applications Available in Military (–55°C to 125°C) Temperature Range Engineering Evaluation (/EM) Samples are Available(1) 3 Description The TPS50601-SP is a radiation hardened, 6.3-V, 6A synchronous step-down converter, which is optimized for small designs through high efficiency and integrating the high-side and low-side MOSFETs. Further space savings are achieved through current mode control, which reduces component count, and a high switching frequency, reducing the inductor's footprint. The devices are offered in a thermally enhanced 20-pin ceramic, dual in-line flatpack package. Device Information(2) PART NUMBER TPS50601-SP PACKAGE BODY SIZE (NOM) CFP (20) 7.38 × 12.70 mm KGD(3) N/A(4) (1) These units are intended for engineering evaluation only. They are processed to a non-compliant flow (that is no burnin, and so forth) and are tested to temperature rating of 25°C only. These units are not suitable for qualification, production, radiation testing or flight use. Parts are not warranted for performance on full MIL specified temperature range of –55°C to 125°C or operating life. (2) For all available packages, see the orderable addendum at the end of the data sheet. (3) Known good die (4) Bare die in waffle pack SPACE SPACE Efficiency (p.u.) Efficiency vs Load Current, Vin = 5 V 1.00 0.95 0.90 0.85 0.80 0.75 0.70 0.65 0.60 0.55 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0.00 Vo = 3.3 V Vo = 1.2 V 0.00 1.00 2.00 3.00 4.00 5.00 6.00 IL- Load Current (A) 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. TPS50601-SP SLVSD45 – DECEMBER 2015 www.ti.com Table of Contents 1 2 3 4 5 6 7 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Description (continued)......................................... Pin Configuration and Functions ......................... Specifications......................................................... 7.1 7.2 7.3 7.4 7.5 7.6 7.7 8 8.3 Feature Description................................................. 15 8.4 Device Functional Modes........................................ 27 1 1 1 2 3 3 7 9 Application and Implementation ........................ 28 9.1 Application Information............................................ 28 9.2 Typical Application ................................................. 28 10 Power Supply Recommendations ..................... 34 11 Layout................................................................... 34 11.1 Layout Guidelines ................................................. 34 11.2 Layout Example .................................................... 35 Absolute Maximum Ratings ...................................... 7 ESD Ratings.............................................................. 7 Recommended Operating Conditions....................... 7 Thermal Information .................................................. 8 Electrical Characteristics........................................... 8 Dissipation Ratings ................................................. 10 Typical Characteristics ............................................ 11 12 Device and Documentation Support ................. 36 12.1 12.2 12.3 12.4 12.5 Detailed Description ............................................ 14 Documentation Support ........................................ Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 36 36 36 36 36 13 Mechanical, Packaging, and Orderable Information ........................................................... 36 8.1 Overview ................................................................. 14 8.2 Functional Block Diagram ....................................... 15 13.1 Device Nomenclature............................................ 36 4 Revision History DATE REVISION December 2015 * NOTES • • 2 Submit Documentation Feedback Initial release. Created separate data sheet for this part number Removed the ψJT thermal metric Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP TPS50601-SP www.ti.com SLVSD45 – DECEMBER 2015 5 Description (continued) The output voltage startup ramp is controlled by the SS/TR pin which allows operation as either a stand alone power supply or in tracking situations. Power sequencing is also possible by correctly configuring the enable and the open drain power good pins. Cycle-by-cycle current limiting on the high-side FET protects the device in overload situations and is enhanced by a low-side sourcing current limit which prevents current runaway. There is also a low-side sinking current limit which turns off the low-side MOSFET to prevent excessive reverse current. Thermal shutdown disables the part when die temperature exceeds thermal shutdown temperature. 6 Pin Configuration and Functions HKH Package 20-Pin CFP Bottom View GND 1 20 PWRGD EN 2 19 SS/TR RT 3 18 COMP SYNC 4 17 VSENSE 16 BOOT Thermal Pad (Bottom Side) 21 VIN 5 PVIN 6 15 PH PVIN 7 14 PH PGND 8 13 PH PGND 9 12 PH PGND 10 11 PH Pin Functions PIN NO. DESCRIPTION NAME 1 GND Return for control circuitry/thermal pad (1) 2 EN EN pin has an internal pullup thus EN pin can be floated to enable the device. As an option external pullup can also be added if desired. Adjust the input undervoltage lockout (UVLO) with two resistors. 3 RT In internal oscillation mode, a resistor is connected between the RT pin and GND to set the switching frequency. 4 SYNC Optional 1-MHz external system clock input. The device operates with an internal oscillator if this pin is left open. 5 VIN Supplies the power to the output FET controllers PVIN Power input. Supplies the power switches of the power converter PGND Return for low-side power MOSFET 6 7 8 9 10 (1) Thermal pad (analog ground) must be connected to PGND external to the package. Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP 3 TPS50601-SP SLVSD45 – DECEMBER 2015 www.ti.com Pin Functions (continued) PIN NO. DESCRIPTION NAME 11 12 13 PH Switch node 16 BOOT A bootstrap capacitor is required between BOOT and PH. The voltage on this capacitor carries the gate drive voltage for the high-side MOSFET. 17 VSENSE Inverting input of the gm error amplifier 18 COMP Error amplifier output and input to the output switch current comparator. Connect frequency compensation to this pin. 19 SS/TR Slow-start and tracking. An external capacitor connected to this pin sets the internal voltage reference rise time. The voltage on this pin overrides the internal reference. It can be used for tracking and sequencing. 20 PWRGD Power Good fault pin is an open-drain connection. Power Good fault pin. Asserts low if output voltage is low due to thermal shutdown, dropout, overvoltage, or EN shutdown, or during slow start. 14 15 Bare Die Information 4 DIE THICKNESS BACKSIDE FINISH BACKSIDE POTENTIAL 15 mils. Silicon with backgrind Ground BOND PAD METALLIZATION COMPOSITION BOND PAD THICKNESS Al5TiN 557.5 nm Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP TPS50601-SP www.ti.com SLVSD45 – DECEMBER 2015 Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP 5 TPS50601-SP SLVSD45 – DECEMBER 2015 www.ti.com Bond Pad Coordinates in Microns 6 DESCRIPTION PAD NUMBER X MIN Y MIN X MAX Y MAX GND 1 400.77 5039.325 578.07 5216.625 EN 2 44.19 4169.79 221.49 4347.09 RT 3 44.19 3894.21 221.49 4071.51 SYNC 4 44.19 3618.63 221.49 3795.93 VIN 5 47.565 2952.27 224.865 3129.57 PVIN 6 280.215 2414.115 457.515 2591.415 PVIN 7 280.215 2170.665 457.515 2347.965 PVIN 8 280.215 1928.115 457.515 2105.415 PVIN 9 280.215 1684.665 457.515 1861.965 PGND 10 254.52 1236.285 431.82 1413.585 PGND 11 254.52 1008.315 431.82 1185.615 PGND 12 254.52 780.345 431.82 957.645 PGND 13 254.52 552.375 431.82 729.675 PGND 14 254.52 324.405 431.82 501.705 PGND 15 254.52 96.435 431.82 273.735 PH 16 1590.12 99.405 1767.42 276.705 PH 17 1590.12 321.435 1767.42 498.735 PH 18 1590.12 555.345 1767.42 732.645 PH 19 1590.12 777.375 1767.42 954.675 PH 20 1590.12 1011.285 1767.42 1188.585 PH 21 1590.12 1233.315 1767.42 1410.615 PH 22 1564.335 1684.665 1741.635 1861.965 PH 23 1564.335 1928.115 1741.635 2105.415 PH 24 1564.335 2170.665 1741.635 2347.965 PH 25 1564.335 2414.115 1741.635 2591.415 BOOT 26 1801.71 3352.14 1979.01 3529.44 VSENSE 27 1801.71 3644.145 1979.01 3821.445 COMP 28 1801.71 3940.92 1979.01 4118.22 SS/TR 29 1801.71 4216.5 1979.01 4393.8 PWRGD 30 1463.67 5039.325 1640.97 5216.625 GND 31 1251.09 5039.325 1428.39 5216.625 GND 32 1038.51 5039.325 1215.81 5216.625 GND 33 825.93 5039.325 1003.23 5216.625 GND 34 613.35 5039.325 790.65 5216.6 Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP TPS50601-SP www.ti.com SLVSD45 – DECEMBER 2015 7 Specifications 7.1 Absolute Maximum Ratings over operating temperature (unless otherwise noted) (1) Input voltage Output voltage MIN MAX VIN –0.3 7 PVIN –0.3 7 EN –0.3 5.5 BOOT –0.3 14 VSENSE –0.3 3.3 COMP –0.3 3.3 PWRGD –0.3 5.5 SS/TR –0.3 5.5 SYNC –0.3 7 BOOT-PH 0 7 PH –1 7 PH 10-ns transient Vdiff (GND to exposed thermal pad) Sink current V V –3 7 –0.2 0.2 V 6 A ±100 µA Output current Source current UNIT PH Current limit RT PH Current limit PVIN Current limit COMP PWRGD A A A ±200 µA –0.1 5 mA Operating junction temperature –55 150 °C Storage temperature, Tstg –65 150 °C (1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. 7.2 ESD Ratings VALUE V(ESD) (1) (2) Electrostatic discharge Human body model (HBM), per ANSI/ESDA/JEDEC JS-001, all pins (1) ±1000 Charged device model (CDM), per JEDEC specification JESD22-C101, all pins (2) ±1000 UNIT V JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. 7.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) MIN TJ Junction operating temperature range –55 NOM MAX UNIT 125 °C Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP 7 TPS50601-SP SLVSD45 – DECEMBER 2015 www.ti.com 7.4 Thermal Information TPS50601-SP THERMAL METRIC (1) HKH (CFP) UNIT 20 PINS RθJC(bot) (1) Junction-to-case (bottom) thermal resistance 0.514 °C/W Taken per Mil Standard 883 method 1012.1 7.5 Electrical Characteristics TJ = –55°C to 125°C, VIN = 3 V to 6.3 V, PVIN = 1.6 V to 6.3 V (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT SUPPLY VOLTAGE (VIN AND PVIN PINS) PVIN operating input voltage VIN operating input voltage VIN internal UVLO threshold 1.6 6.3 V 3 6.3 V 3 V VIN rising 2.75 VIN shutdown supply current VEN = 0 V 2.5 5.9 mA VIN operating – non switching supply current VSENSE = VBG 5 10 mA 1.13 1.18 VIN internal UVLO hysteresis 50 mV ENABLE AND UVLO (EN PIN) Rising Enable threshold Falling 1.05 1.09 V Input current VEN = 1.1 V 3.2 μA Hysteresis current VEN = 1.3 V 3 μA VOLTAGE REFERENCE 0 A ≤ Iout ≤ 6 A Voltage reference –55°C 0.767 0.795 0.804 25°C 0.785 0.795 0.804 125°C 0.785 0.795 0.815 V MOSFET High-side switch resistance BOOT-PH = 2.2 V 55 mΩ High-side switch resistance (1) BOOT-PH = 6.3 V 50 mΩ Low-side switch resistance (1) VIN = 6.3 V 50 mΩ ERROR AMPLIFIER Error amplifier transconductance (gm) (2) –2 μA < ICOMP < 2 μA, V(COMP) = 1 V Error amplifier dc gain (2) VSENSE = 0.792 V Error amplifier source/sink (2) Start switching threshold V(COMP) = 1 V, 40-mV input overdrive (2) 1300 μS 39000 V/V ±125 μA 0.25 COMP to Iswitch gm (2) V 18 A/V CURRENT LIMIT High-side switch current limit threshold Low-side switch sourcing current limit (3) (3) Low-side switch sinking current limit VIN = 6.3 V 8 11 A VIN = 6.3 V 7 10 A 3 A 175 °C 10 °C VIN = 6.3 V THERMAL SHUTDOWN Thermal shutdown Thermal shutdown hysteresis INTERNAL SWITCHING FREQUENCY Internally set frequency (1) (2) (3) 8 RT = Open 395 500 585 kHz Measured at pins Ensured by design only. Not tested in production. Parameter is not tested in production. Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP TPS50601-SP www.ti.com SLVSD45 – DECEMBER 2015 Electrical Characteristics (continued) TJ = –55°C to 125°C, VIN = 3 V to 6.3 V, PVIN = 1.6 V to 6.3 V (unless otherwise noted) PARAMETER TEST CONDITIONS MIN RT = 100 kΩ (1%) Externally set frequency TYP MAX UNIT 480 RT = 485 kΩ (1%) 100 RT = 47 kΩ (1%) 1000 kHz EXTERNAL SYNCHRONIZATION SYNC out low-to-high rise time (10%/90%) Cload = 25 pF 25 111 ns SYNC out high-to-low fall time (90%/10%) Cload = 25 pF 3 15 ns Falling edge delay time (4) 180 SYNC out high level threshold IOH = 50 µA SYNC out low level threshold IOL = 50 µA SYNC in low level threshold 2 V 600 800 1.85 Percent of program frequency mV mV SYNC in high level threshold SYNC in frequency range (5) ° V –5% 5% 100 1000 kHz 175 ns PH (PH PIN) Minimum on time Measured at 10% to 90% of VIN, 25°C, IPH = 2 A Minimum off time BOOT-PH ≥ 3 V 94 500 ns BOOT (BOOT PIN) BOOT-PH UVLO 2.2 3 V 90 mV SLOW START AND TRACKING (SS/TR PIN) SS charge current SS/TR to VSENSE matching μA 2.5 V(SS/TR) = 0.4 V 30 VSENSE falling (fault) 91 % Vref VSENSE rising (good) 94 % Vref VSENSE rising (fault) 109 % Vref VSENSE falling (good) 106 % Vref POWER GOOD (PWRGD PIN) VSENSE threshold Output high leakage VSENSE = Vref, V(PWRGD) = 5 V Output low I(PWRGD) = 2 mA Minimum VIN for valid output V(PWRGD) < 0.5 V at 100 μA Minimum SS/TR voltage for PWRGD (4) (5) 30 0.6 181 nA 0.3 V 1 V 1.4 V Bench verified. Not tested in production. Parameter is production tested at nominal voltage with VIN = PVIN = 5V. Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP 9 TPS50601-SP SLVSD45 – DECEMBER 2015 www.ti.com 7.6 Dissipation Ratings See (1) (2) (3) (4) (1) (2) (3) (4) PACKAGE RθJA THERMAL IMPEDANCE, JUNCTION TO AMBIENT RθJC THERMAL IMPEDANCE, JUNCTION TO CASE (THERMAL PAD) RθJB THERMAL IMPEDANCE, JUNCTION TO BOARD HKH 39.9°C/W 0.52°C/W 43.1°C/W Maximum power dissipation may be limited by overcurrent protection Power rating at a specific ambient temperature, TA, should be determined with a junction temperature of 150°C. This is the point where distortion starts to substantially increase. Thermal management of the PCB should strive to keep the junction temperature at or below 150°C for best performance and long-term reliability. See power dissipation estimate in Application and Implementation for more information. Test board conditions: (a) 2.5 inches × 2.5 inches, 4 layers, thickness: 0.062 inch (b) 2-oz. copper traces located on the top of the PCB (c) 2-oz. copper ground planes on the 2 internal layers and bottom layer (d) 40.010-inch thermal vias located under the device package For information on thermal characteristics, see SPRA953. 10000000 Life (Hours) 1000000 Duty Cycle 100 80 60 40 20 100000 10000 1000 95 105 115 125 135 145 Operating Junction Temperature (°C) A. See data sheet for absolute maximum and minimum recommended operating conditions. B. Product operating life design goal is >15 years for 65°C ≤ TJ ≤ 95°C based on silicon technology characterization per MIL-PRF-38535. C. The predicted operating lifetime versus junction temperature is based on reliability modeling using electromigration as the dominant failure mechanism affecting device wearout for the specific device process and design characteristics. Figure 1. 6-A Continuous Current Estimated Device Life 10 Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP TPS50601-SP www.ti.com SLVSD45 – DECEMBER 2015 7.7 Typical Characteristics 60.00 0.83 VIN = 3 V 58.00 0.82 VIN = 6.3 V Voltage Reference (V) Current Sharing (%) 56.00 54.00 POL 2 52.00 50.00 48.00 POL 1 46.00 0.81 0.80 0.79 0.78 44.00 0.77 42.00 0.76 40.00 0.00 2.00 4.00 6.00 8.00 10.00 ±75 12.00 ±50 0 ±25 75 100 125 C003 6000 Nom Min Max VIN = 3 V Shutdown Quiescent Current ( A) Oscillator Frequency (kHz) 50 Figure 3. Voltage Reference vs Temperature Figure 2. Current Sharing vs Load Current 1250 1000 750 500 250 VIN = 6.3 V 5000 4000 3000 2000 1000 0 0 ±75 ±50 ±25 0 25 50 75 100 Junction Temperature (ƒC) 125 ±75 ±25 0 25 50 75 100 Junction Temperature (ƒC) Figure 4. Oscillator Frequency vs Temperature 125 C005 Figure 5. Shutdown Quiescent Current vs Temperature ±5 VIN = 3 V En Pin Pull-Up Current ( A) VIN = 6.3 V 4 ±50 C004 5 EN Pin Hysteresis Current ( A) 25 Junction Temperature (ƒC) IL- Current Load (A) 3 2 1 0 VIN = 3 V VIN = 6.3 V ±6 ±7 ±8 ±9 ±10 ±75 ±50 ±25 0 25 50 75 100 Junction Temperature (ƒC) 125 ±75 ±50 Figure 6. EN Pin Hysteresis Current vs Temperature ±25 0 25 50 75 100 Junction Temperature (ƒC) C006 125 C007 Figure 7. EN Pin Pullup Current vs Temperature Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP 11 TPS50601-SP SLVSD45 – DECEMBER 2015 www.ti.com 1.170 VIN = 3 V En Pin UVLO Threshold (V) 1.165 VIN = 6.3 V 1.160 1.155 1.150 1.145 1.140 1.135 1.130 ±75 ±50 0 ±25 25 50 75 100 125 Junction Temperature (ƒC) C008 Figure 8. EN Pin UVLO Threshold vs Temperature Non-Switching Operating Quiescent Current ( A) Typical Characteristics (continued) 8000 VIN = 6.3 V 7000 6500 6000 5500 5000 4500 4000 3500 3000 ±75 ±50 ±25 0 25 50 75 100 Junction Temperature (ƒC) 125 C009 Figure 9. Non-Switching Operating Quiescent Current (VIN) vs Temperature 3.2 0.05 VIN = 3 V VIN = 6.3 V 3.0 (SS - Vsense) Offset (V) Iss Slow Start Charge Current ( A) VIN = 3 V 7500 2.8 2.6 2.4 2.2 VIN = 6.3 V 0.04 0.03 0.02 0.01 0.00 ±75 ±50 ±25 0 25 50 75 100 125 Junction Temperature (ƒC) ±75 ±50 ±25 0 25 50 75 100 Junction Temperature (ƒC) C010 Figure 10. Slow Start Charge Current vs Temperature 125 C011 Figure 11. (SS-VSENSE) Offset vs Temperature 170 12 11 On-State Resistance (m Current Limit Threshold (A) VIN = 3 V 150 10 9 8 7 VIN = 6.3 V 130 110 90 70 50 30 VIN = 6.3 V 6 10 ±75 ±50 ±25 0 25 50 75 100 Junction Temperature (ƒC) ±75 ±50 ±25 0 25 50 75 100 Junction Temperature (ƒC) C012 Figure 12. High-Side Current Limit Threshold vs Temperature 12 125 125 C002 Figure 13. Low-Side RDS(On) vs Temperature Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP TPS50601-SP www.ti.com SLVSD45 – DECEMBER 2015 Typical Characteristics (continued) 180 250 On-State Resistance (m 160 Minimum Controllable On Time (ns) VIN = 3 V VIN = 6.3 V 140 120 100 80 60 40 20 VIN = 3 V VIN = 6.3 V 200 150 100 50 ±75 ±50 ±25 0 25 50 75 100 Junction Temperature (ƒC) 125 ±75 ±50 ±25 0 25 50 75 100 Junction Temperature (ƒC) C001 Figure 14. High-Side RDS(On) vs Temperature 125 C013 Figure 15. Minimum Controllable On-Time vs Temperature Minimum Controllable Duty Ratio (%) 15 VIN = 3 V VIN = 6.3 V 10 5 0 ±75 ±50 ±25 0 25 50 75 Junction Temperature (ƒC) 100 125 C014 Figure 16. Minimum Controllable Duty Ratio vs Temperature Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP 13 TPS50601-SP SLVSD45 – DECEMBER 2015 www.ti.com 8 Detailed Description 8.1 Overview The device is a 6.3-V or 6-A synchronous step-down (buck) converter with two integrated N-channel MOSFETs. To improve performance during line and load transients, the device implements a constant frequency, peak current mode control, which also simplifies external frequency compensation. The wide switching frequency, 100 kHz to 1 MHz, allows for efficiency and size optimization when selecting the output filter components. The device is designed for safe monotonic startup into prebiased loads. The default start up is when VIN is typically 3 V. The EN pin has an internal pullup current source that can be used to adjust the input voltage UVLO with two external resistors. In addition, the EN pin can be floating for the device to operate with the internal pullup current. The total operating current for the device is approximately 5 mA when not switching and under no load. When the device is disabled, the supply current is typically less than 2.5 mA. The integrated MOSFETs allow for high-efficiency power supply designs with continuous output currents up to 6 A. The MOSFETs have been sized to optimize efficiency for lower duty cycle applications. The device reduces the external component count by integrating the boot recharge circuit. The bias voltage for the integrated high-side MOSFET is supplied by a capacitor between the BOOT and PH pins. The boot capacitor voltage is monitored by a BOOT to PH UVLO (BOOT-PH UVLO) circuit allowing the PH pin to be pulled low to recharge the boot capacitor. The device can operate over duty cycle range per Equation 2 and Equation 3 as long as the boot capacitor voltage is higher than the preset BOOT-PH UVLO threshold, which is typically 2.2 V. The output voltage can be stepped down to as low as the 0.795-V voltage reference (Vref). The device has a power good comparator (PWRGD) with hysteresis which monitors the output voltage through the VSENSE pin. The PWRGD pin is an open-drain MOSFET which is pulled low when the VSENSE pin voltage is less than 91% or greater than 109% of the reference voltage Vref and asserts high when the VSENSE pin voltage is 94% to 106% of the Vref. The SS/TR (slow start/tracking) pin is used to minimize inrush currents or provide power-supply sequencing during power-up. A small-value capacitor or resistor divider should be coupled to the pin for slow start or critical power-supply sequencing requirements. The device is protected from output overvoltage, overload, and thermal fault conditions. The device minimizes excessive output overvoltage transients by taking advantage of the overvoltage circuit power good comparator. When the overvoltage comparator is activated, the high-side MOSFET is turned off and prevented from turning on until the VSENSE pin voltage is lower than 106% of the Vref. The device implements both high-side MOSFET overload protection and bidirectional low-side MOSFET overload protections, which help control the inductor current and avoid current runaway. The device also shuts down if the junction temperature is higher than thermal shutdown trip point. The device is restarted under control of the slow-start circuit automatically when the junction temperature drops 10°C typical below the thermal shutdown trip point. 14 Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP TPS50601-SP www.ti.com SLVSD45 – DECEMBER 2015 8.2 Functional Block Diagram PWRGD VIN EN Shutdown Ip Enable Comparator Ih Thermal Shutdown PVIN PVIN UVLO Shutdown UV Shutdown Logic Logic Enable Threshold OV Boot Charge Current Sense Minimum Clamp Pulse Skip ERROR AMPLIFIER VSENSE BOOT Boot UVLO V/I SS/TR HS MOSFET Current Comparator Voltage Reference Power Stage & Deadtime Control Logic PH PH Slope Compensation VIN Overload Recovery and Clamp Oscillator Regulator RT Bias LS MOSFET Current Limit Current Sense PGND SYNC Detect COMP SYNC PGND RT Thermal Pad/GND 8.3 Feature Description 8.3.1 VIN and Power VIN Pins (VIN and PVIN) The device allows for a variety of applications by using the VIN and PVIN pins together or separately. The VIN pin voltage supplies the internal control circuits of the device. The PVIN pin voltage provides the input voltage to the power converter system. If tied together, the input voltage for VIN and PVIN can range from 3 to 6.3 V. If using the VIN separately from PVIN, the VIN pin must be between 3 and 6.3 V, and the PVIN pin can range from as low as 1.6 to 6.3 V. A voltage divider connected to the EN pin can adjust the input voltage UVLO appropriately. Adjusting the input voltage UVLO on the PVIN pin helps to provide consistent power-up behavior. 8.3.2 PVIN vs Frequency With VIN tied to PVIN, minimum off-time determines what output voltage is achievable over frequency range. 8.3.3 Voltage Reference The voltage reference system produces a precise voltage reference as indicated in Electrical Characteristics. Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP 15 TPS50601-SP SLVSD45 – DECEMBER 2015 www.ti.com Feature Description (continued) 8.3.4 Adjusting the Output Voltage The output voltage is set with a resistor divider from the output (VOUT) to the VSENSE pin. TI recommends to use 1% tolerance or better divider resistors. Start with a 10 kΩ for R15 (top resistor) and use Equation 1 to calculate R38 (bottom resistor divider). To improve efficiency at light loads, consider using larger-value resistors. If the values are too high, the regulator is more susceptible to noise and voltage errors from the VSENSE input current are noticeable. Vref R38 = R15 Vo - Vref where • Vref = 0.795 V (1) The minimum output voltage and maximum output voltage can be limited by the minimum on-time of the highside MOSFET and bootstrap voltage (BOOT-PH voltage) respectively. For more information, see Bootstrap Voltage (BOOT) and Low Dropout Operation. 8.3.5 Maximum Duty Cycle Limit The TPS50601-SP can operate at duty cycle per Equation 2 and Equation 3 as long as the boot capacitor voltage is higher than the preset BOOT-PH UVLO threshold, which is typically 2.2 V. Duty cycle can be calculated based on Equation 2. VOUT + IOUT_max · RTesr + IOUT_max · Rds_low D(VIN) = VIN - IOUT_max · Rds_high + IOUT_max · Rds_low where • • • • • RTesr = Rdcr + Rtrace Rdcr is the dc resistance of the inductor. Rtrace is the dc trace resistance (miscellaneous drop). Rds_high is the maximum RDS of the high-side MOSFET. Rds_low is the maximum RDS of the low-side MOSFET. (2) 8.3.6 PVIN vs Frequency With VIN tied to PVIN, minimum off-time determines the output voltage that is achievable over frequency range. For VIN = PVIN must be ≥ 3 V. For VIN = 3 V, PVIN can vary from 1.6 to 6.3 V as highlighted in Electrical Characteristics. This is given by Equation 3. VO + IO(Rds _ onLS + Rmisc ) PVin _ min(fSW ) = 1 - Toff _ min· fSW where • • • Rds_onLS = Low-side Rds-on Rmisc = Miscellaneous trace drops Toff_min = Minimum off time (3) Using this approach, the designer can calculate minimum PVIN required for specific VOUT as indicated in the example in Figure 17. 16 Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP TPS50601-SP www.ti.com SLVSD45 – DECEMBER 2015 Feature Description (continued) VO = 1.5 V PVin_min(100 kHz = 1.889 V) PVin_min(1000 kHz = 3.396 V) fsw - Switching Frequency - Hz Figure 17. PVIN vs Frequency 8.3.7 Safe Start-Up into Prebiased Outputs The device is designed to prevent the low-side MOSFET from discharging a prebiased output. During monotonic prebiased startup, the low-side MOSFET is not allowed to sink current until the SS/TR pin voltage is higher than 1.4 V. 8.3.8 Error Amplifier The device uses a transconductance error amplifier. The error amplifier compares the VSENSE pin voltage to the lower of the SS/TR pin voltage or the internal 0.795-V voltage reference. The transconductance of the error amplifier is 1300 μA/V during normal operation. The frequency compensation network is connected between the COMP pin and ground. Error amplifier dc gain is typically 39000 V/V with minimum value of 22000 V/V per design. 8.3.9 Slope Compensation The device adds a compensating ramp to the switch current signal. This slope compensation prevents subharmonic oscillations. The available peak inductor current remains constant over the full duty cycle range. Minimum peak-to-peak inductor current should be greater than 1 A. 8.3.10 Enable and Adjust UVLO The EN pin provides electrical on and off control of the device. When the EN pin voltage exceeds the threshold voltage, the device starts operation. If the EN pin voltage is pulled below the threshold voltage, the regulator stops switching and enters low Iq state. If an external Schottky diode is used from VIN to boot, then a bleeder may be required 500 mV. The EN pin has a small pullup current, Ip, which sets the default state of the pin to enable when no external components are connected. The pullup current is also used to control the voltage hysteresis for the UVLO function because it increases by Ih after the EN pin crosses the enable threshold. Calculate the UVLO thresholds with Equation 4 and Equation 5. TPS50601-SP VIN ip ih R1 EN R2 Figure 18. Adjustable VIN UVLO TPS50601-SP PVIN ip ih R1 EN R2 Figure 19. Adjustable PVIN UVLO, VIN ≥ 3 V TPS50601-SP PVIN VIN ip ih R1 EN R2 Figure 20. Adjustable VIN and PVIN UVLO æV ö VSTART ç ENFALLING ÷ - VSTOP è VENRISING ø R1 = æ V ö Ip ç1 - ENFALLING ÷ + Ih V ENRISING ø è 18 Submit Documentation Feedback (4) Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP TPS50601-SP www.ti.com SLVSD45 – DECEMBER 2015 Feature Description (continued) R1´ VENFALLING VSTOP - VENFALLING + R1(Ip + Ih ) R2 = where • • • • Ih = 3 μA Ip = 3.2 μA VENRISING = 1.131 V VENFALLING = 1.09 V (5) 8.3.11 Adjustable Switching Frequency and Synchronization (SYNC) The switching frequency of the device supports three modes of operations. The modes of operation are set by the conditions on the RT and SYNC pins. At a high level, these modes can be described as master, internal oscillator, and external synchronization modes. In master mode, the RT pin should be left floating; the internal oscillator is set to 500 kHz, and the SYNC pin is set as an output clock. The SYNC output is in phase with respect to the internal oscillator. SYNC out signal level is the same as VIN level with 50% duty cycle. SYNC signal feeding the slave module—which is in phase with the master clock—gets internally inverted (180° out of phase with the master clock) internally in the slave module. In internal oscillator mode, a resistor is connected between the RT pin and GND. The SYNC pin requires a 10kΩ resistor to GND for this mode to be effective. The switching frequency of the device is adjustable from 100 kHz to 1 MHz by placing a maximum of 510 kΩ and a minimum of 47 kΩ respectively. To determine the RT resistance for a given switching frequency, use Equation 6 or the curve in Figure 21. To reduce the solution size, the designer should set switching frequency as high as possible, but consider the tradeoffs of supply efficiency and minimum controllable on-time. -1.0549 RT(FSW) = 67009 x FSW where • • RT in kΩ FSW in kHz (6) 3 1.2x10 3 1.08x10 RT(FSW) 960 840 RT - kW 720 600 RT = 500 kW 480 360 240 120 0 0 100 200 300 400 500 600 700 800 900 1x 10 3 Switching Frequency (FSW) - kHz Figure 21. RT vs Switching Frequency When operating the converter in internal oscillator mode (internal oscillator determines the switching frequency (500 kHz) default), the synchronous pin becomes the output and there is a phase inversion. When trying to parallel with another converter, the RT pin of the second (slave) converter must have its RT pin populated such that the converter frequency of the slave converter must be within ±5% of the master converter. This is required because the RT pin also sets the proper operation of slope compensation. Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP 19 TPS50601-SP SLVSD45 – DECEMBER 2015 www.ti.com Feature Description (continued) In external synchronization mode, a resistor is connected between the RT pin and GND. The Sync pin requires a toggling signal for this mode to be effective. The switching frequency of the device goes 1:1 with that of Sync pin. External system clock-user supplied sync clock signal determines the switching frequency. If no external clock signal is detected for 20 µs, then TPS50601-SP transitions to its internal clock, which is typically 500 kHz. An external synchronization using an inverter to obtain phase inversion is necessary. RT values of the master and slave converter must be within ±5% of the external synchronization frequency. This is necessary for proper slope compensation. A resistance in the RT pin is required for proper operation of the slope compensation circuit. To determine the RT resistance for a given switching frequency, use Equation 6 or the curve in Figure 21. To reduce the solution size, the designer should set switching frequency as high as possible, but consider the tradeoffs of supply efficiency and minimum controllable on-time. These modes are described in Table 1. Table 1. Switching Frequency, SYNC and RT Pin Usage Table RT PIN Float SWITCHING FREQUENCY SYNC PIN DESCRIPTION AND NOTES Generates an output signal 500 kHz SYNC pin behaves as an output. SYNC output signal is 180° out of phase to the internal 500-kHz switching frequency. 10-kΩ resistor to AGND 100 kHz to 1 MHz Internally generated switching frequency is based upon the resistor value present at the RT pin. Internally synchronized to external clock Set value of RT that corresponds to the externally supplied sync frequency. 47- to 485-kΩ resistor User-supplied sync clock or to AGND TPS50601-SP master device sync output 8.3.12 Slow Start (SS/TR) The device uses the lower voltage of the internal voltage reference or the SS/TR pin voltage as the reference voltage and regulates the output accordingly. A capacitor on the SS/TR pin to ground implements a slow-start time. The device has an internal pullup current source of 5 mA that charges the external slow-start capacitor. Equation 7 shows the calculations for the slow-start time (Tss, 10% to 90%) and slow-start capacitor (Css). The voltage reference (Vref) is 0.795 V and the slow-start charge current (Iss) is 2.5 μA. t SS (ms) = Css (nF) ´ Vref (V) Iss (µA) (7) When the input UVLO is triggered, the EN pin is pulled below 1.032 V, or a thermal shutdown event occurs the device stops switching and enters low current operation. At the subsequent power-up, when the shutdown condition is removed, the device does not start switching until it has discharged its SS/TR pin to ground ensuring proper soft-start behavior. 8.3.13 Power Good (PWRGD) The PWRGD pin is an open-drain output. When the VSENSE pin is between 94% and 106% of the internal voltage reference, the PWRGD pin pull-down is deasserted and the pin floats. TI recommends to use a pullup resistor between 10 to 100 kΩ to a voltage source that is 5.5 V or less. The PWRGD is in a defined state when the VIN input voltage is greater than 1 V but has reduced current sinking capability. The PWRGD achieves full current sinking capability when the VIN input voltage is above 3 V. The PWRGD pin is pulled low when VSENSE is lower than 91% or greater than 109% of the nominal internal reference voltage. Also, the PWRGD is pulled low, if the input UVLO or thermal shutdown are asserted, the EN pin is pulled low or the SS/TR pin is below 1.4 V. 8.3.14 Bootstrap Voltage (BOOT) and Low Dropout Operation The device has an integrated boot regulator, and requires a small ceramic capacitor between the BOOT and PH pins to provide the gate drive voltage for the high-side MOSFET. The boot capacitor is charged when the BOOT pin voltage is less than VIN and BOOT-PH voltage is below regulation. The value of this ceramic capacitor should be 0.1 μF. TI recommends a ceramic capacitor with an X7R- or X5R-grade dielectric with a voltage rating of 10 V or higher because of the stable characteristics over temperature and voltage. 20 Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP TPS50601-SP www.ti.com SLVSD45 – DECEMBER 2015 To improve dropout, the device is designed to operate at a high duty cycle as long as the BOOT to PH pin voltage is greater than the BOOT-PH UVLO threshold, which is typically 2.1 V. When the voltage between BOOT and PH drops below the BOOT-PH UVLO threshold, the high-side MOSFET is turned off and the low-side MOSFET is turned on allowing the boot capacitor to be recharged. In applications with split-input voltage rails, high duty cycle operation can be achieved as long as (VIN – PVIN) > 4 V. Maximum switching frequency is also limited by minimum on-time (specified in Electrical Characteristics) as indicated by Equation 8. Switching frequency will be worst case at no load conditions. 1 VO + Rds_on · (IO) FSW = = T VIN · (Ton_max) (8) 8.3.15 Sequencing (SS/TR) Many of the common power-supply sequencing methods can be implemented using the SS/TR, EN, and PWRGD pins. The sequential method is shown in Figure 22 using two TPS50601-SP devices. The power good of the first device is coupled to the EN pin of the second device, which enables the second power supply after the primary supply reaches regulation. TPS50601-SP TPS50601-SP PWRGD EN EN SS/TR SS/TR PWRGD Figure 22. Sequential Start-Up Sequence Figure 23 shows the method implementing ratiometric sequencing by connecting the SS/TR pins of two devices together. The regulator outputs ramp up and reach regulation at the same time. When calculating the slow-start time, the pullup current source must be doubled in Equation 7. Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP 21 TPS50601-SP SLVSD45 – DECEMBER 2015 www.ti.com TPS50601-SP EN SS/TR PWRGD TPS50601-SP EN SS/TR PWRGD Figure 23. Ratiometric Start-Up Sequence Ratiometric and simultaneous power-supply sequencing can be implemented by connecting the resistor network of R1 and R2 (shown in Figure 24) to the output of the power supply that needs to be tracked or another voltage reference source. Using Equation 9 and Equation 10, the tracking resistors can be calculated to initiate the Vout2 slightly before, after, or at the same time as Vout1. Equation 11 is the voltage difference between Vout1 and Vout2. To design a ratiometric start-up in which the Vout2 voltage is slightly greater than the Vout1 voltage when Vout2 reaches regulation, use a negative number in Equation 9 and Equation 10 for ΔV. Equation 11 results in a positive number for applications where the Vout2 is slightly lower than Vout1 when Vout2 regulation is achieved. The ΔV variable is 0 V for simultaneous sequencing. To minimize the effect of the inherent SS/TR to VSENSE offset (Vssoffset, 29 mV) in the slow-start circuit and the offset created by the pullup current source (Iss, 2 μA) and tracking resistors, the Vssoffset and Iss are included as variables in the equations. To ensure proper operation of the device, the calculated R1 value from Equation 9 must be greater than the value calculated in Equation 12. R1 = Vout2 + D V Vssoffset ´ Vref Iss (9) Vref ´ R1 R2 = Vout2 + DV - Vref DV = Vout1 - Vout2 R1 > 2800 ´ Vout1- 180 ´ DV 22 (10) (11) (12) Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP TPS50601-SP www.ti.com SLVSD45 – DECEMBER 2015 TPS50601-SP EN VOUT1 SS/TR PWRGD TPS50601-SP EN VOUT 2 R1 SS/TR R2 PWRGD R4 R3 Figure 24. Ratiometric and Simultaneous Start-Up Sequence 8.3.16 Output Overvoltage Protection (OVP) The device incorporates an output OVP circuit to minimize output voltage overshoot. For example, when the power supply output is overloaded, the error amplifier compares the actual output voltage to the internal reference voltage. If the VSENSE pin voltage is lower than the internal reference voltage for a considerable time, the output of the error amplifier demands maximum output current. After the condition is removed, the regulator output rises and the error amplifier output transitions to the steady-state voltage. In some applications with small output capacitance, the power supply output voltage can respond faster than the error amplifier. This leads to the possibility of an output overshoot. The OVP feature minimizes the overshoot by comparing the VSENSE pin voltage to the OVP threshold. If the VSENSE pin voltage is greater than the OVP threshold, the high-side MOSFET is turned off, preventing current from flowing to the output and minimizing output overshoot. When the VSENSE voltage drops lower than the OVP threshold, the high-side MOSFET is allowed to turn on at the next clock cycle. 8.3.17 Overcurrent Protection The device is protected from overcurrent conditions by cycle-by-cycle current limiting on both the high-side and low-side MOSFET. 8.3.17.1 High-Side MOSFET Overcurrent Protection The device implements current mode control which uses the COMP pin voltage to control the turn off of the highside MOSFET and the turn on of the low-side MOSFET on a cycle-by-cycle basis. Each cycle the switch current and the current reference generated by the COMP pin voltage are compared, when the peak switch current intersects the current reference, the high-side switch is turned off. 8.3.17.2 Low-Side MOSFET Overcurrent Protection While the low-side MOSFET is turned on its conduction current is monitored by the internal circuitry. During normal operation the low-side MOSFET sources current to the load. At the end of every clock cycle, the low-side MOSFET sourcing current is compared to the internally set low-side sourcing current limit. If the low-side sourcing current is exceeded, the high-side MOSFET is not turned on and the low-side MOSFET stays on for the next cycle. The high-side MOSFET is turned on again when the low-side current is below the low-side sourcing current limit at the start of a cycle. Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP 23 TPS50601-SP SLVSD45 – DECEMBER 2015 www.ti.com The low-side MOSFET may also sink current from the load. If the low-side sinking current limit is exceeded, the low-side MOSFET is turned off immediately for the rest of that clock cycle. In this scenario, both MOSFETs are off until the start of the next cycle. When the low-side MOSFET turns off, the switch node increases and forward biases the high-side MOSFET parallel diode (the high-side MOSFET is still off at this stage). 8.3.18 TPS50601-SP Thermal Shutdown The internal thermal shutdown circuitry forces the device to stop switching if the junction temperature exceeds 175°C typically. The device reinitiates the power-up sequence when the junction temperature drops below 165°C typically. 8.3.19 Turn-On Behavior Minimum on-time specification determines the maximum operating frequency of the design. As the unit starts up and goes through its soft-start process, the required duty-cycle is less than the minimum controllable on-time. This can cause the converter to skip pulses. Thus, instantaneous output pulses can be higher or lower than the desired voltage. This behavior is only evident when operating at high frequency with high bandwidth. When the minimum on-pulse is greater than the minimum controllable on-time, the turn-on behavior is normal. When operating at low frequencies (100 kHz or less), the turn-on behavior does not exhibit any ringing at initial startup. 8.3.20 Small Signal Model for Loop Response Figure 25 shows an equivalent model for the device control loop, which can be modeled in a circuit simulation program to check frequency response and transient responses. The error amplifier is a transconductance amplifier with a gm of 1300 μA/V. The error amplifier can be modeled using an ideal voltage-controlled current source. The resistor, Roea (30 MΩ), and capacitor, Coea (20.7 pF), model the open-loop gain and frequency response of the error amplifier. The 1-mV ac voltage source between the nodes a and b effectively breaks the control loop for the frequency response measurements. Plotting a/c and c/b show the small signal responses of the power stage and frequency compensation respectively. Plotting a/b shows the small signal response of the overall loop. The dynamic loop response can be checked by replacing the RL with a current source with the appropriate load-step amplitude and step rate in a time domain analysis. PH VOUT Power Stage 18 A/V a b c 0.8 V R3 Coea C2 R1 RESR VSENSE CO COMP C1 Roea gm 1300 mA/V RL R2 Figure 25. Small Signal Model For Loop Response 8.3.21 Simple Small Signal Model for Peak Current Mode Control Figure 26 is a simple small signal model that can be used to understand how to design the frequency compensation. The device power stage can be approximated to a voltage-controlled current source (duty cycle modulator) supplying current to the output capacitor and load resistor. Equation 13 shows the control to output transfer function, which consists of a dc gain, one dominant pole, and one ESR zero. The quotient of the change in switch current and the change in COMP pin voltage (node c in Figure 25) is the power stage transconductance (gmps), which is 18 A/V for the device. The dc gain of the power stage is the product of gmps and the load 24 Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP TPS50601-SP www.ti.com SLVSD45 – DECEMBER 2015 resistance (RL) as shown in Equation 14 with resistive loads. As the load current increases, the dc gain decreases. This variation with load may seem problematic at first glance, but fortunately, the dominant pole moves with load current (see Equation 15). The combined effect is highlighted by the dashed line in Figure 27. As the load current decreases, the gain increases and the pole frequency lowers, keeping the 0-dB crossover frequency the same for the varying load conditions, which makes it easier to design the frequency compensation. VOUT VC RESR RL gm ps CO Figure 26. Simplified Small Signal Model for Peak Current Mode Control VOUT Adc VC RESR fp RL gm ps CO fz Figure 27. Simplified Frequency Response for Peak Current Mode Control æ ç1+ 2p VOUT = Adc ´ è VC æ ç1+ è 2p ö s ÷ ´ ¦z ø ö s ÷ ´ ¦p ø (13) Adc = gmps ´ RL (14) 1 ¦p = C O ´ R L ´ 2p (15) 1 CO ´ RESR ´ 2p ¦z = where • • • • gmea is the GM amplifier gain (1300 μA/V). gmps is the power stage gain (18 A/V). RL is the load resistance. CO is the output capacitance. Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP 25 TPS50601-SP SLVSD45 – DECEMBER 2015 • www.ti.com RESR is the equivalent series resistance of the output capacitor. (16) 8.3.22 Small Signal Model for Frequency Compensation The device uses a transconductance amplifier for the error amplifier and readily supports two of the commonly used frequency compensation circuits shown in Figure 28. In Type 2A, one additional high-frequency pole is added to attenuate high-frequency noise. The following design guidelines are provided for advanced users who prefer to compensate using the general method. The step-by-step design procedure described in Detailed Design Procedure may also be used. VOUT R1 VSENSE COMP Type 2A Vref R2 gm ea Roea R3 Coea C2 Type 2B R3 C1 C1 Figure 28. Types of Frequency Compensation The general design guidelines for device loop compensation are as follows: 1. Determine the crossover frequency ƒc. A good starting point is one-tenth of the switching frequency, ƒSW. 2. R3 can be determined by: 2p ´ ¦ c ´ VOUT ´ Co R3 = gmea ´ Vref ´ gmps where • • • gmea is the GM amplifier gain ( 1300 μA/V). gmps is the power stage gain (18 A/V). Vref is the reference voltage (0.795 V) (17) æ ö 1 ç ¦p = ÷ CO ´ RL ´ 2p ø . 3. Place a compensation zero at the dominant pole è C1 can be determined by R ´ Co C1 = L R3 (18) 4. C2 is optional. It can be used to cancel the zero from the equivalent series resistance (ESR) of the output capacitor Co. R ´ Co C2 = ESR R3 (19) NOTE For PSpice models and WEBENCH design tool, see the Tools & Software tab. 1. PSpice average model (stability – bode plot) 2. PSpice transient model (switching waveforms) 3. WEBENCH design tool www.ti.com/product/TPS50601-SP/toolssoftware 26 Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP TPS50601-SP www.ti.com SLVSD45 – DECEMBER 2015 8.4 Device Functional Modes 8.4.1 Fixed-Frequency PWM Control The device uses fixed frequency, peak current mode control. The output voltage is compared through external resistors on the VSENSE pin to an internal voltage reference by an error amplifier which drives the COMP pin. An internal oscillator initiates the turn on of the high-side power switch. The error amplifier output is converted into a current reference which compares to the high-side power switch current. When the power switch current reaches the current reference generated by the COMP voltage level, the high-side power switch is turned off and the low-side power switch is turned on. 8.4.2 Continuous Current Mode (CCM) Operation As a synchronous buck converter, the device normally works in CCM under all load conditions. Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP 27 TPS50601-SP SLVSD45 – DECEMBER 2015 www.ti.com 9 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 9.1 Application Information The TPS50601-SP device is a highly-integrated synchronous step-down DC-DC converter. The device is used to convert a higher DC-DC input voltage to a lower DC output voltage with a maximum output current of 6 A. The TPS50601-SP user's guide is available on the TI website, SLVU499. The guide highlights standard EVM test results, schematic, and BOM for reference. (Basic design equations in following sections are provided for reference only) 9.2 Typical Application PVIN VIN TPS50601-SP BOOT VIN Cin Cboot VOUT Lo EN PH Co PWRGD R1 VSENSE SS/TR RT/CLK COMP Css R3 Rrt C2 C1 R2 GND Exposed Thermal Pad Figure 29. Typical Application Schematic 9.2.1 Design Requirements This example details the design of a high frequency switching regulator design using ceramic output capacitors. A few parameters must be known in order to start the design process. These parameters are typically determined at the system level. For this example, we start with the following known parameters: Table 2. Design Parameters DESIGN PARAMETER 3.3 V Output current 6A Transient response 1-A load step Input voltage ΔVout = 5% 5 V nominal, 4.5 to 6.3 V Output voltage ripple Start input voltage (rising Vin) 28 EXAMPLE VALUE Output voltage 33 mV p-p 4.425V Stop input voltage (falling Vin) 4.234V Switching frequency 480 kHz Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP TPS50601-SP www.ti.com SLVSD45 – DECEMBER 2015 9.2.2 Detailed Design Procedure 9.2.2.1 Operating Frequency The first step is to decide on a switching frequency for the regulator. There is a trade off between higher and lower switching frequencies. Higher switching frequencies may produce smaller a solution size using lower valued inductors and smaller output capacitors compared to a power supply that switches at a lower frequency. However, the higher switching frequency causes extra switching losses, which hurt the converter’s efficiency and thermal performance. In this design, a moderate switching frequency of 480 kHz is selected to achieve both a small solution size and a high efficiency operation. 9.2.2.2 Output Inductor Selection To calculate the value of the output inductor, use Equation 20. KIND is a coefficient that represents the amount of inductor ripple current relative to the maximum output current. The inductor ripple current is filtered by the output capacitor. Therefore, choosing high inductor ripple currents impact the selection of the output capacitor since the output capacitor must have a ripple current rating equal to or greater than the inductor ripple current. In general, the inductor ripple value is at the discretion of the designer; however, KIND is normally from 0.1 to 0.4 for the majority of applications. L1 = Vinm ax - Vout Vout × Io × Kind Vinm ax × f sw (20) For this design example, use KIND = 0.1 and the inductor value is calculated to be 2.78 µH. For this design, a nearest standard value was chosen: 3.3 µH. For the output filter inductor, it is important that the RMS current and saturation current ratings not be exceeded. The RMS and peak inductor current can be found from Equation 22 and Equation 23. Vinmax - Vout Vout × Iripple = L1 Vinmax × f sw (21) ILrms = Io2 + 1 æ Vo × (Vinmax - Vo ) ö ×ç ÷ 12 çè Vinmax × L1× f sw ÷ø 2 (22) Iripple ILpeak = Iout + 2 (23) For this design, the RMS inductor current is 6.02 A and the peak inductor current is 6.84 A. The chosen inductor is a Coilcraft MSS1048 series 3.3 µH. It has a saturation current rating of 7.38 A and a RMS current rating of 7.22 A. The current flowing through the inductor is the inductor ripple current plus the output current. During power up, faults or transient load conditions, the inductor current can increase above the calculated peak inductor current level calculated above. In transient conditions, the inductor current can increase up to the switch current limit of the device. For this reason, the most conservative approach is to specify an inductor with a saturation current rating equal to or greater than the switch current limit rather than the peak inductor current. 9.2.2.3 Output Capacitor Selection There are three primary considerations for selecting the value of the output capacitor. The output capacitor determines the modulator pole, the output voltage ripple, and how the regulator responds to a large change in load current. The output capacitance needs to be selected based on the more stringent of these three criteria The desired response to a large change in the load current is the first criteria. The output capacitor needs to supply the load with current when the regulator can not. This situation would occur if there are desired hold-up times for the regulator where the output capacitor must hold the output voltage above a certain level for a specified amount of time after the input power is removed. The regulator is also temporarily not able to supply sufficient output current if there is a large, fast increase in the current needs of the load such as a transition from no load to full load. The regulator usually needs two or more clock cycles for the control loop to see the change Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP 29 TPS50601-SP SLVSD45 – DECEMBER 2015 www.ti.com in load current and output voltage and adjust the duty cycle to react to the change. The output capacitor must be sized to supply the extra current to the load until the control loop responds to the load change. The output capacitance must be large enough to supply the difference in current for 2 clock cycles while only allowing a tolerable amount of droop in the output voltage. Equation 24 shows the minimum output capacitance necessary to accomplish this. 2 × DIout Co > f sw × DVout (24) Where ΔIout is the change in output current, Fsw is the regulators switching frequency and ΔVout is the allowable change in the output voltage. For this example, the transient load response is specified as a 5% change in Vout for a load step of 1A. For this example, ΔIout = 1.0 A and ΔVout = 0.05 x 3.3 = 0.165 V. Using these numbers gives a minimum capacitance of 25 μF. This value does not take the ESR of the output capacitor into account in the output voltage change. For ceramic capacitors, the ESR is usually small enough to ignore in this calculation. Equation 25 calculates the minimum output capacitance needed to meet the output voltage ripple specification. Where fsw is the switching frequency, Vripple is the maximum allowable output voltage ripple, and Iripple is the inductor ripple current. In this case, the maximum output voltage ripple is 33mV. Under this requirement, Equation 25 yields 13.2 µF. 1 1 Co > × 8 × f sw Voripple Iripple (25) Equation 26 calculates the maximum ESR an output capacitor can have to meet the output voltage ripple specification. Equation 26 indicates the ESR should be less than 19.7 mΩ. In this case, the ceramic caps’ ESR is much smaller than 19.7 mΩ. Voripple Resr < Iripple (26) Additional capacitance de-ratings for aging, temperature and DC bias should be factored in which increases this minimum value. For this example, a 47 μF 6.3V X5R ceramic capacitor with 3 mΩ of ESR is be used. Capacitors generally have limits to the amount of ripple current they can handle without failing or producing excess heat. An output capacitor that can support the inductor ripple current must be specified. Some capacitor data sheets specify the RMS (Root Mean Square) value of the maximum ripple current. Equation 27 can be used to calculate the RMS ripple current the output capacitor needs to support. For this application, Equation 27 yields 485mA. Vout × (Vinmax - Vout ) Icorms = 12 × Vinmax × L1× f sw (27) 9.2.2.4 Input Capacitor Selection The TPS50601-SP requires a high quality ceramic, type X5R or X7R, input decoupling capacitor of at least 4.7 µF of effective capacitance on the PVIN input voltage pins and 4.7 µF on the Vin input voltage pin. In some applications additional bulk capacitance may also be required for the PVIN input. The effective capacitance includes any DC bias effects. The voltage rating of the input capacitor must be greater than the maximum input voltage. The capacitor must also have a ripple current rating greater than the maximum input current ripple of the TPS50601-SP. The input ripple current can be calculated using Equation 28. Icirms = Iout × Vout (Vinmin - Vout ) × Vinmin Vinmin (28) The value of a ceramic capacitor varies significantly over temperature and the amount of DC bias applied to the capacitor. The capacitance variations due to temperature can be minimized by selecting a dielectric material that is stable over temperature. X5R and X7R ceramic dielectrics are usually selected for power regulator capacitors because they have a high capacitance to volume ratio and are fairly stable over temperature. The output capacitor must also be selected with the DC bias taken into account. The capacitance value of a capacitor decreases as the DC bias across a capacitor increases. For this example design, a ceramic capacitor with at least a 25-V voltage rating is required to support the maximum input voltage. For this example, one 10 μF and 30 Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP TPS50601-SP www.ti.com SLVSD45 – DECEMBER 2015 one 4.7-µF 25-V capacitors in parallel have been selected as the VIN and PVIN inputs are tied together so the TPS50601-SP may operate from a single supply. The input capacitance value determines the input ripple voltage of the regulator. The input voltage ripple can be calculated using Equation 29. Using the design example values, Ioutmax = 6 A, Cin = 14.7 μF, FSW = 480 kHz, yields an input voltage ripple of 213 mV and a RMS input ripple current of 2.95 A. Ioutmax × 0.25 DVin = Cin × f sw (29) 9.2.2.5 Slow Start Capacitor Selection The slow start capacitor determines the minimum amount of time it takes for the output voltage to reach its nominal programmed value during power up. This is useful if a load requires a controlled voltage slew rate. This is also used if the output capacitance is very large and would require large amounts of current to quickly charge the capacitor to the output voltage level. The large currents necessary to charge the capacitor may make the TPS50601-SP reach the current limit or excessive current draw from the input power supply may cause the input voltage rail to sag. Limiting the output voltage slew rate solves both of these problems. The soft start capacitor value can be calculated using Equation 30. For the example circuit, the soft start time is not too critical since the output capacitor value is 47 μF which does not require much current to charge to 3.3 V. The example circuit has the soft start time set to an arbitrary value of 3.5 ms which requires a 10-nF capacitor. In TPS50601-SP, Iss is 2.5 µA typical, and Vref is 0.795 V. Tss(ms) x Iss(μA) C5(nF) = Vref(V) (30) 9.2.2.6 Bootstrap Capacitor Selection A 0.1-µF ceramic capacitor must be connected between the BOOT to PH pin for proper operation. TI recommends to use a ceramic capacitor with X5R or better grade dielectric. The capacitor should have a voltage rating of 10 V or higher. 9.2.2.7 Undervoltage Lockout (UVLO) Set Point The UVLO can be adjusted using the external voltage divider network of R6a and R7a. R6a is connected between VIN and the EN pin of the TPS50601-SP and R7a is connected between EN and GND . The UVLO has two thresholds, one for power up when the input voltage is rising and one for power down or brown outs when the input voltage is falling. For the example design, the supply should turn on and start switching once the input voltage increases above selected voltage (UVLO start or enable). After the regulator starts switching, it should continue to do so until the input voltage falls below (UVLO stop or disable) voltage. Equation 4 and Equation 5 can be used to calculate the values for the upper and lower resistor values. For the stop voltages specified the nearest standard resistor value for R6a is 10.0 kΩ and for R7a is 3.4 kΩ. 9.2.2.8 Output Voltage Feedback Resistor Selection The resistor divider network R5 and R6 is used to set the output voltage. For the example design, 10 kΩ was selected for R6. Using Equation 31, R5 is calculated as 31.25 kΩ. The nearest standard 1% resistor is 31.6 kΩ. V re f R5 9 R ± 9 UH I u R6 (31) 9.2.2.8.1 Minimum Output Voltage Due to the internal design of the TPS50601-SP, there is a minimum output voltage limit for any given input voltage. The output voltage can never be lower than the internal voltage reference of 0.8 V. Above 0.8 V, the output voltage may be limited by the minimum controllable on time. The minimum output voltage in this case is given by Equation 32 spacer VOUTmin = Ontimemin × ƒsmax (VINmax + IOUTmin (RDS2min - RDS1min)) - IOUTmin (RL + RDS2min) where • • VOUTmin = Minimum achievable output voltage Ontimemin = Minimum controllable on-time (175 ns maximum) Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP 31 TPS50601-SP SLVSD45 – DECEMBER 2015 • • • • • • www.ti.com ƒsmax = Maximum switching frequency including tolerance VINmax = Maximum input voltage IOUTmin = Minimum load current RDS1min = Minimum high-side MOSFET on-resistance (36-32 mΩ typical) RDS2min = Minimum low-side MOSFET on-resistance (19 mΩ typical) RL = Series resistance of output inductor (32) 9.2.2.9 Compensation Component Selection There are several industry techniques used to compensate DC/DC regulators. The method presented here is easy to calculate and yields high phase margins. For most conditions, the regulator has a phase margin between 60 and 90 degrees. The method presented here ignores the effects of the slope compensation that is internal to the TPS50601-SP. Since the slope compensation is ignored, the actual cross over frequency is usually lower than the cross over frequency used in the calculations. Use WEBENCH, Pspice model for simulation. First, the modulator pole, fpmod, and the esr zero, fzmod must be calculated using Equation 33 and Equation 34. For Cout, use a derated value of 22.4 µF. use Equation 35 and Equation 36 to estimate a starting point for the closed loop crossover frequency fco. Then the required compensation components may be derived. For this design example, fpmod is 12.9 kHz and fzmod is 2730 kHz. Equation 35 is the geometric mean of the modulator pole and the esr zero and Equation 36 is the geometric mean of the modulator pole and one half the switching frequency. Use a frequency near the lower of these two values as the intended crossover frequency fco. In this case Equation 35 yields 175 kHz and Equation 36 yields 55.7 kHz. The lower value is 55.7 kHz. A slightly higher frequency of 60.5 kHz is chosen as the intended crossover frequency. Iout f pmod = 2 × p × Vout × Cout (33) f zm od = 1 2 × p × RESR × Cout f co = f pmod × f zmod f co = f pmod × (34) (35) f sw 2 (36) Now the compensation components can be calculated. First calculate the value for R2 which sets the gain of the compensated network at the crossover frequency. Use Equation 37 to determine the value of R2. 2p × f c × Vout × Cout R2 = gmea × Vref × gmps (37) Next calculate the value of C3. Together with R2, C3 places a compensation zero at the modulator pole frequency. Equation 38 to determine the value of C3. Vout × Cout C3 = Iout × R2 (38) Using Equation 37 and Equation 38 the standard values for R2 and C3 are 1.69 kΩ and 8200 pF. An additional high frequency pole can be used if necessary by adding a capacitor in parallel with the series combination of R2 and C3. The pole frequency is given by Equation 39. This pole is not used in this design. 1 fp = 2 × p × R2 × Cp (39) 32 Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP TPS50601-SP www.ti.com SLVSD45 – DECEMBER 2015 9.2.3 Application Curve A. Per EVM - for additional details see the User's Guide, SLVU499 Figure 30. Typical Switching Waveform for 100-kHz Switching Operation Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP 33 TPS50601-SP SLVSD45 – DECEMBER 2015 www.ti.com 10 Power Supply Recommendations The TPS50601-SP is designed to operate from an input voltage supply range between 3.0V and 6.3V. This supply voltage must be well regulated. Power supplies must be well bypassed for proper electrical performance. This includes a minimum of one 4.7 µF (after de-rating) ceramic capacitor, type X5R or better from PVIN to GND, and from VIN to GND. Additional local ceramic bypass capacitance may be required in systems with small input ripple specifications, in addition to bulk capacitance if the TPS50601-SP device is located more than a few inches away from its input power supply. In systems with an auxiliary power rail available, the power stage input, PVIN, and the analog power input, VIN, may operate from separate input supplies. See Layout Example (layout recommendation) for recommended bypass capacitor placement. 11 Layout 11.1 Layout Guidelines • • • • • • • • • • • • • • • • • 34 Layout is a critical portion of good power supply design. See Layout Example for a PCB layout example. The top layer contains the main power traces for VIN, VOUT, and VPHASE. Also on the top layer are connections for the remaining pins of the TPS50601-SP and a large top side area filled with ground. The top layer ground area should be connected to the internal ground layer(s) using vias at the input bypass capacitor, the output filter capacitor and directly under the TPS50601-SP device to provide a thermal path from the exposed thermal pad land to ground The GND pin should be tied directly to the power pad under the IC and the power pad. For operation at full rated load, the top side ground area together with the internal ground plane, must provide adequate heat dissipating area. There are several signals paths that conduct fast changing currents or voltages that can interact with stray inductance or parasitic capacitance to generate noise or degrade the power supplies performance. To help eliminate these problems, the PVIN pin should be bypassed to ground with a low ESR ceramic bypass capacitor with X5R or X7R dielectric. Care should be taken to minimize the loop area formed by the bypass capacitor connections, the PVIN pins, and the ground connections. The VIN pin must also be bypassed to ground using a low ESR ceramic capacitor with X5R or X7R dielectric. Make sure to connect this capacitor to the quite analog ground trace rather than the power ground trace of the PVIn bypass capacitor. Since the PH connection is the switching node, the output inductor should be located close to the PH pins, and the area of the PCB conductor minimized to prevent excessive capacitive coupling. The output filter capacitor ground should use the same power ground trace as the PVIN input bypass capacitor. Try to minimize this conductor length while maintaining adequate width. The small signal components should be grounded to the analog ground path as shown. The RT pin is sensitive to noise so the RT resistor should be located as close as possible to the IC and routed with minimal lengths of trace. It may be possible to obtain acceptable performance with alternate PCB layouts, however this layout has been shown to produce good results and is meant as a guideline. Land pattern and stencil information is provided in the data sheet addendum. Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP TPS50601-SP www.ti.com SLVSD45 – DECEMBER 2015 11.2 Layout Example Bond pad connected to ground for thermal path Figure 31. PCB Layout Example Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP 35 TPS50601-SP SLVSD45 – DECEMBER 2015 www.ti.com 12 Device and Documentation Support 12.1 Documentation Support 12.1.1 Related Documentation For related documentation see the following: TPS50601SP EVM, 6-A/12-A, SWIFT ™ Regulator Evaluation Module, SLVU499 12.2 Community Resources The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers. Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and contact information for technical support. 12.3 Trademarks SWIFT, E2E are trademarks of Texas Instruments. All other trademarks are the property of their respective owners. 12.4 Electrostatic Discharge Caution These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. 12.5 Glossary SLYZ022 — TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 13 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. 13.1 Device Nomenclature KGD Known good die RHA Radiation hardness assurance for space systems 5962R10221 Same device as TPS50601-SP, shown with standard microcircuit drawing (SMD) TPS50601-SP Same device as 5962R10221, shown with TI package drawing 36 Submit Documentation Feedback Copyright © 2015, Texas Instruments Incorporated Product Folder Links: TPS50601-SP PACKAGE OPTION ADDENDUM www.ti.com 13-Sep-2022 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) (3) Device Marking Samples (4/5) (6) 5962-1022101VSC ACTIVE CFP HKH 20 1 RoHS-Exempt & Green AU N / A for Pkg Type -55 to 125 5962-1022101VS C TPS50601MHKHV 5962R1022101V9A ACTIVE XCEPT KGD 0 25 RoHS & Green Call TI N / A for Pkg Type -55 to 125 5962R1022101VSC ACTIVE CFP HKH 20 1 RoHS-Exempt & Green AU N / A for Pkg Type -55 to 125 5962R1022101VS C TPS50601-RHA TPS50601HKH/EM ACTIVE CFP HKH 20 1 RoHS-Exempt & Green AU N / A for Pkg Type 25 to 25 TPS50601HKH/EM EVAL ONLY Samples (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) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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