TPS65251

ACTIVE

4.5-V TO 18-V input, 3A/2A/2A output, synchronous triple buck converter

Product details

Rating Catalog Operating temperature range (°C) -40 to 125 Topology Buck Type Converter Iout (max) (A) 3 Vin (min) (V) 4.5 Vin (max) (V) 18 Switching frequency (min) (kHz) 300 Switching frequency (max) (kHz) 2200 Features Adjustable current limit, Enable, Frequency synchronization, Phase Interleaving, Power good, Soft Start Adjustable, Synchronous Rectification, UVLO adjustable Control mode current mode Vout (min) (V) 0.8 Vout (max) (V) 17 Iq (typ) (µA) 20000 Duty cycle (max) (%) 100
Rating Catalog Operating temperature range (°C) -40 to 125 Topology Buck Type Converter Iout (max) (A) 3 Vin (min) (V) 4.5 Vin (max) (V) 18 Switching frequency (min) (kHz) 300 Switching frequency (max) (kHz) 2200 Features Adjustable current limit, Enable, Frequency synchronization, Phase Interleaving, Power good, Soft Start Adjustable, Synchronous Rectification, UVLO adjustable Control mode current mode Vout (min) (V) 0.8 Vout (max) (V) 17 Iq (typ) (µA) 20000 Duty cycle (max) (%) 100
VQFN (RHA) 40 36 mm² 6 x 6
  • Wide Input Supply Voltage Range (4.5 to 18 V)
  • 0.8 V, 1% Accuracy Reference
  • Continuous Loading: 3 A (Buck 1),
    2 A (Buck 2 and 3)
  • Maximum Current: 3.5 A (Buck 1),
    2.5 A (Buck 2 and 3)
  • Adjustable Switching Frequency
    300 kHz to 2.2 MHz Set by External Resistor
  • Dedicated Enable for Each Buck
  • External Synchronization Pin for Oscillator
  • External Enable/Sequencing and Soft-Start Pins
  • Adjustable Current Limit Set By External Resistor
  • Soft-Start Pins
  • Current-Mode Control With Simple Compensation Circuit
  • Powergood
  • Optional Low-Power Mode Operation for Light Loads
  • VQFN Package, 40-Pin 6 mm × 6 mm RHA
  • Wide Input Supply Voltage Range (4.5 to 18 V)
  • 0.8 V, 1% Accuracy Reference
  • Continuous Loading: 3 A (Buck 1),
    2 A (Buck 2 and 3)
  • Maximum Current: 3.5 A (Buck 1),
    2.5 A (Buck 2 and 3)
  • Adjustable Switching Frequency
    300 kHz to 2.2 MHz Set by External Resistor
  • Dedicated Enable for Each Buck
  • External Synchronization Pin for Oscillator
  • External Enable/Sequencing and Soft-Start Pins
  • Adjustable Current Limit Set By External Resistor
  • Soft-Start Pins
  • Current-Mode Control With Simple Compensation Circuit
  • Powergood
  • Optional Low-Power Mode Operation for Light Loads
  • VQFN Package, 40-Pin 6 mm × 6 mm RHA

The TPS65251 features three synchronous wide input range high efficiency buck converters. The converters are designed to simplify its application while giving the designer the option to optimize their usage according to the target application.

The converters can operate in 5-, 9-, 12- or 15-V systems and have integrated power transistors. The output voltage can be set externally using a resistor divider to any value between 0.8 V and close to the input supply. Each converter features enable pin that allows a delayed start-up for sequencing purposes, soft-start pin that allows adjustable soft-start time by choosing the soft-start capacitor, and a current limit (RLIMx) pin that enables designer to adjust current limit by selecting an external resistor and optimize the choice of inductor. The current mode control allows a simple RC compensation.

The switching frequency of the converters can either be set with an external resistor connected to ROSC pin or can be synchronized to an external clock connected to SYNC pin if needed. The switching regulators are designed to operate from 300 kHz to 2.2 MHz. 180° out of phase operation between Buck 1 and Buck 2, 3 (Buck 2 and 3 run in phase) minimizes the input filter requirements.

TPS65251 features a supervisor circuit that monitors each converter output. The PGOOD pin is asserted once sequencing is done, all PG signals are reported and a selectable end of reset time lapses. The polarity of the PGOOD signal is active high.

TPS65251 also features a light load pulse skipping mode (PSM) by allowing the LOW_P pin tied to V3V. The PSM mode allows for a reduction on the input power supplied to the system when the host processor is in standby (low-activity) mode.

The TPS65251 features three synchronous wide input range high efficiency buck converters. The converters are designed to simplify its application while giving the designer the option to optimize their usage according to the target application.

The converters can operate in 5-, 9-, 12- or 15-V systems and have integrated power transistors. The output voltage can be set externally using a resistor divider to any value between 0.8 V and close to the input supply. Each converter features enable pin that allows a delayed start-up for sequencing purposes, soft-start pin that allows adjustable soft-start time by choosing the soft-start capacitor, and a current limit (RLIMx) pin that enables designer to adjust current limit by selecting an external resistor and optimize the choice of inductor. The current mode control allows a simple RC compensation.

The switching frequency of the converters can either be set with an external resistor connected to ROSC pin or can be synchronized to an external clock connected to SYNC pin if needed. The switching regulators are designed to operate from 300 kHz to 2.2 MHz. 180° out of phase operation between Buck 1 and Buck 2, 3 (Buck 2 and 3 run in phase) minimizes the input filter requirements.

TPS65251 features a supervisor circuit that monitors each converter output. The PGOOD pin is asserted once sequencing is done, all PG signals are reported and a selectable end of reset time lapses. The polarity of the PGOOD signal is active high.

TPS65251 also features a light load pulse skipping mode (PSM) by allowing the LOW_P pin tied to V3V. The PSM mode allows for a reduction on the input power supplied to the system when the host processor is in standby (low-activity) mode.

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Technical documentation

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Type Title Date
* Data sheet TPS65251 4.5-V to 18-V Input, High-Current, Synchronous Step-Down Three Buck Switcher With Integrated FET datasheet (Rev. G) PDF | HTML 16 Feb 2018
EVM User's guide TPS65251 Buck Converter Evaluation Module User's Guide (Rev. B) PDF | HTML 26 May 2021
Application note Measure Power Stage Gain and Slope Compensation in PCM (Peak Current Mode) BUCK (Rev. A) PDF | HTML 01 Apr 2019
Selection guide Power Management Guide 2018 (Rev. R) 25 Jun 2018
Application note TPS65250/1/2/3 LAYOUT GUIDE 15 Jan 2013
Application note TPS65250/1/2/3 Output Filter Selection Guidelines 15 Jan 2013

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

TPS65251EVM — Evaluation Module for TPS65251, PMU with 3 DC/DC Converters, up to 18Vin

The TPS65251EVM is designed to help the user easily evaluate and test the operation and functionality of the TPS65251 buck converters (3-ch DC/DC; Ch1: 1.2 V, 3 A; Ch2: 1.8 V, 2 A; Ch3: 3.3 V, 2 A). The EVM converts a 4.5-V to 18-V input voltage designed to a regulated Ch1 = 1.2 V, Ch2 = 1.8 V, Ch3 (...)

Not available on TI.com
Simulation model

TPS65251 TINA-TI Average Reference Design

SLVM274.TSC (94 KB) - TINA-TI Reference Design
Simulation model

TPS65251 TINA-TI Average Spice Model

SLVM275.ZIP (8 KB) - TINA-TI Spice Model
Simulation model

TPS65251 TINA-TI Transient Reference Design

SLVM512.TSC (154 KB) - TINA-TI Reference Design
Simulation model

TPS65251 TINA-TI Transient Spice Model

SLVM513.ZIP (24 KB) - TINA-TI Spice Model
Simulation model

TPS65251 Unencrypted PSpice Average Model Package (Rev. A)

SLVM511A.ZIP (43 KB) - PSpice Model
Simulation model

TPS65251 Unencrypted PSpice Transient Model Package (Rev. A)

SLVM519A.ZIP (31 KB) - PSpice Model
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VQFN (RHA) 40 Ultra Librarian

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