TPS65251-2

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) 17 Switching frequency (min) (kHz) 300 Switching frequency (max) (kHz) 2200 Features Adjustable current limit, Enable, Frequency synchronization, Light Load Efficiency, 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) 1000 Duty cycle (max) (%) 90
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) 17 Switching frequency (min) (kHz) 300 Switching frequency (max) (kHz) 2200 Features Adjustable current limit, Enable, Frequency synchronization, Light Load Efficiency, 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) 1000 Duty cycle (max) (%) 90
VQFN (RHA) 40 36 mm² 6 x 6
  • Wide input supply voltage range (4.5 to 18 V)
  • Output range: 0.8 V to VIN – 1 V
  • 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
  • Adjustable current limit set by external resistor
  • Soft-start pins
  • Current-mode control with simple compensation circuit
  • Power good
  • Automatic PFM/PWM operation
  • VQFN package, 40-pin 6-mm × 6-mm RHA
  • Wide input supply voltage range (4.5 to 18 V)
  • Output range: 0.8 V to VIN – 1 V
  • 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
  • Adjustable current limit set by external resistor
  • Soft-start pins
  • Current-mode control with simple compensation circuit
  • Power good
  • Automatic PFM/PWM operation
  • VQFN package, 40-pin 6-mm × 6-mm RHA

The TPS65251-x 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 an 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 the 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 the 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-x features a supervisor circuit that monitors each converter output. The PGOOD pin is asserted when 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.

All converters feature an automatic low-power pulse PFM skipping mode, which improves efficiency during light loads and standby operation, while ensuring a very-low output ripple, allowing for a value of less than 2% at low output voltages.

The TPS65251-x 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 an 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 the 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 the 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-x features a supervisor circuit that monitors each converter output. The PGOOD pin is asserted when 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.

All converters feature an automatic low-power pulse PFM skipping mode, which improves efficiency during light loads and standby operation, while ensuring a very-low output ripple, allowing for a value of less than 2% at low output voltages.

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Technical documentation

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Type Title Date
* Data sheet TPS65251-x 4.5-V to 18-V Input, High Current, Synchronous Step Down Three Buck Switchers With Integrated FET datasheet (Rev. B) PDF | HTML 04 Jan 2022
Application note Measure Power Stage Gain and Slope Compensation in PCM (Peak Current Mode) BUCK (Rev. A) PDF | HTML 01 Apr 2019

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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 (...)

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