Quad, 1 A, 5.5 V, Synchronous Step-Down Regulators with One RF LDO Regulator

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Part Details
Part Models 2
1ku List Price Starting From $2.61
  • PVINx voltage range: 3 V to 5.5 V
  • Continuous output current
    • Channel 1 to Channel 4 (buck): 1 A
    • Channel 5 (LDO): 250 mA
  • 3.2 MHz fixed PWM switching frequency
  • Synchronization input function
  • Buck regulators run at 90° out of phase
  • Individual precision enable input
  • Power-on reset output
  • Integrated compensation
  • Soft start and power-up sequencing reduce inrush current
  • Active output discharge switch function
  • Stable with low ESR output ceramic capacitors
  • OVLO, UVM, and UVLO
  • TSD protection
  • Qualified for automotive applications
Additional Details
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The ADP5138 integrates four high performance synchronous step-down regulators and one low noise radio frequency (RF) low dropout (LDO) regulator. The device runs from PVINx input voltages of 3 V to 5.5 V. The output voltage of each channel is factory set or can be programmed down to 0.8 V with a resistor. Each step-down regulator can provide up to 1 A of continuous output current and the LDO can provide 250 mA of output current.

The ADP5138 runs at the fixed PWM switching frequency, 3.2 MHz, or can be synchronized to the external clock from 2.8 MHz to 3.5 MHz, which is outside the amplitude modulation (AM) band. The four buck regulators run at 90° out of phase to reduce the input ripple current and the input capacitor size, thereby helping to lower system electromagnetic interference (EMI).

The ADP5138 integrates internal compensation to simplify the design. The internal soft start circuitry and power-up sequencing help reduce the input inrush current.

The ADP5138 monitors the input voltage and provides input overvoltage lockout (OVLO), undervoltage monitor (UVM), and undervoltage lockout (UVLO) features. It also monitors the undervoltage and overvoltage of the outputs. The power-on reset (POR) signal is asserted when the input or output voltage fault occurs.

Additional protection includes overcurrent protection (OCP) and thermal shutdown (TSD).

The ADP5138 operates over the −40°C to +125°C operating temperature range (junction), and is available in a 28-lead LFCSP package.


  • Automotive
  • Industrial and instrumentation
  • DC-to-dc point of load application
Part Models 2
1ku List Price Starting From $2.61

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Software & Part Ecosystem

Software & Part Ecosystem

Evaluation Kit

Evaluation Kits 1

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ADP5138 Evaluation Board



ADP5138 Evaluation Board

ADP5138 Evaluation Board

Features and Benefits

  • Full featured evaluation board for the ADP5138
  • Compact solution size
  • 4-layer high glass transition temperature PCB for superior thermal performance
  • Connections through vertical printed circuit tail pin headers
  • Supply voltage
    • 3 V to 5.5 V (5 V typical) for PVINx
  • Fixed or adjustable output options for quad 1 A buck regulators and one 250 mA RF LDO regulator
  • Independent enable control for each regulator
  • Power-on reset output

Product Detail

The ADP5138W-1-EVALZ evaluation board provides a complete and compact solution that allows users to evaluate the performance of the ADP5138 with a near ideal printed circuit board (PCB) layout.

The main device on the evaluation board, the ADP5138, integrates four high performance synchronous step-down regulators and one low noise radio frequency (RF) low dropout (LDO) regulator.

The ADP5138W-1-EVALZ has independent enable controls for each regulator that allow flexible configuration when evaluating the ADP5138.

Full details on the ADP5138 regulator are provided in the ADP5138 data sheet, available from Analog Devices, Inc. Consult the data sheet in conjunction with this user guide when working with the ADP5138W-1-EVALZ.

Tools & Simulations

Tools & Simulations 1

LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

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