TPS65251 4.5-V TO 18-V input, 3A/2A/2A output, synchronous triple buck converter | TI.com

TPS65251 (ACTIVE)

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

 

Description

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.

Features

  • 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

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Parametrics

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Part number Order Vin (Min) (V) Vin (Max) (V) Vout (Min) (V) Vout (Max) (V) Iout (Max) (A) Regulated outputs (#) Switching frequency (Min) (kHz) Switching frequency (Max) (kHz) Iq (Typ) (mA) Features Control mode Duty cycle (Max) (%) Operating temperature range (C) Rating Package Group Type Package size: mm2:W x L (PKG)
TPS65251 Order now 4.5     18     0.8     17     3     3     300     2200     20     Adjustable Current Limit
Enable
Frequency Synchronization
Phase Interleaving
Power Good
Synchronous Rectification
UVLO Adjustable    
Current Mode     100     -40 to 125     Catalog     VQFN | 40     Converter     40VQFN: 36 mm2: 6 x 6 (VQFN | 40)    
TPS65250 Order now 4.5     18     0.8     17     3     3     300     2200     20     Adjustable Current Limit
Enable
Frequency Synchronization
Power Good
Synchronous Rectification
UVLO Adjustable    
Current Mode     95     -40 to 125     Catalog     VQFN | 40     Converter     40VQFN: 36 mm2: 6 x 6 (VQFN | 40)    
TPS65251-1 Order now 4.5     17     0.8     17     3     3     300     2200     1     Adjustable Current Limit
Enable
Frequency Synchronization
Light Load Efficiency
Phase Interleaving
Power Good
Synchronous Rectification
UVLO Adjustable    
Current Mode     90     -40 to 125     Catalog     VQFN | 40     Converter     40VQFN: 36 mm2: 6 x 6 (VQFN | 40)    
TPS65251-2 Order now 4.5     17     0.8     17     3     3     300     2200     1     Adjustable Current Limit
Enable
Frequency Synchronization
Light Load Efficiency
Phase Interleaving
Power Good
Synchronous Rectification
UVLO Adjustable    
Current Mode     90     -40 to 125     Catalog     VQFN | 40     Converter     40VQFN: 36 mm2: 6 x 6 (VQFN | 40)    
TPS65251-3 Order now 4.5     17     0.8     17     3     3     300     2200     1