4.5-V to 28-V, dual-synchronous buck controller for low output voltage rails


Product details


Vin (Min) (V) 3 Vin (Max) (V) 28 Vout (Min) (V) 0.76 Vout (Max) (V) 5.5 Iout (Max) (A) 15 Iq (Typ) (uA) 350 Switching frequency (Min) (kHz) 240 Switching frequency (Max) (kHz) 420 Features Enable, Light Load Efficiency, Power Good, Synchronous Rectification Operating temperature range (C) -40 to 85 Regulated outputs (#) 2 Number of Phases 1 Rating Catalog open-in-new Find other Buck controllers (external switch)

Package | Pins | Size

VQFN (RGE) 24 16 mm² 4 x 4 open-in-new Find other Buck controllers (external switch)


  • High Efficiency, Low-Power Consumption, Shutdowns to <1 µA
  • Fixed Frequency Emulated On-Time Control, Frequency Selectable
    From Three Options
  • D-CAP Mode Enables Fast Transient Response
  • Auto-Skip Mode
  • Less Than 1% Initial Reference Accuracy
  • Low Output Ripple
  • Wide Input Voltage Range: 3 V to 28 V
  • Output Voltage Range: 0.76 V to 5.5 V
  • Low-Side RDS(ON) Loss-less Current Sensing
  • Adaptive Gate Drivers With Integrated Boost Diode
  • Internal 1.2-ms Voltage-Servo Soft-Start
  • Powergood Signals for Each Channel With Delay Timer
  • Output Discharge During Disable, Fault
    • Notebook I/O and Low-Voltage System Bus

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The TPS51124 is a dual, adaptive on-time D-CAP™ mode synchronous buck controller. The part enables system designers to cost effectively complete the suite of notebook power bus regulators with the absolute lowest external component count and lowest standby consumption. The fixed frequency emulated adaptive on-time control supports seamless operation between PWM mode at heavy load condition and reduced frequency operation at light load for high efficiency down to milliampere range. The main control loop for the TPS51124 uses the D-CAP mode that optimized for low ESR output capacitors such as POSCAP or SP-CAP promises fast transient response with no external compensation. Simple and separate power good signals for each channel allow flexibility of power sequencing. The part provides a convenient and efficient operation with supply input voltages (V5IN, V5FILT) ranging from 4.5 V to 5.5 V, conversion voltages (drain voltage for the synchronous high-side MOSFET) from 3 V to 28 V and output voltages from 0.76 V to 5.5 V.

The TPS51124 is available in 24-pin VQFN package specified from –40°C to 85°C ambient temperature range.

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Technical documentation

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Type Title Date
* Data sheet TPS51124 Dual Synchronous Step-Down Controller for Low-Voltage Power Rails datasheet (Rev. C) Dec. 31, 2014
Application note Intel Core i3, i5, i7 [Arrandale] Reference Design Jul. 21, 2010
Technical article Embedded Computers with TI Power in a myriad of applications May 15, 2010
User guide Using the TPS51124 (Rev. A) Jun. 30, 2008
Application note Adaptive Constant On-Time (D-CAPTM) Control Study in Notebook Applications (Rev. B) Dec. 04, 2007

Design & development

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Design tools & simulation

SLVJ003B.ZIP (95 KB) - PSpice Model
SLVJ004B.ZIP (117 KB) - TINA-TI Reference Design
SLVM021.ZIP (18 KB) - TINA-TI Spice Model
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Reference designs

Dual sync Buck with TPS51124
PMP4575 — Synchronous dual output buck converter supplies two cores with 7A each out of 5V to 20V source
Design files

CAD/CAE symbols

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VQFN (RGE) 24 View options

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