MAXREFDES1120: 3.3V/4A Synchronous Step-Down DC-DC Converter Using MAX15038


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The MAX15038 is a synchronous buck converter which delivers up to 4A load current at output voltages from 0.6V to 90% of VIN. The integrated circuit (IC) supports the input voltage from 2.9V to 5.5V. The total output error is less than ±1% overload, line, and temperature ranges. The MAX15038 features fixed-frequency pulse-width modulation (PWM) mode operation with a switching frequency range of 500kHz to 2MHz set by an external resistor. It also provides the option of operating in a skip mode to improve light-load efficiency. High-frequency operation allows for small-size external components and an all-ceramic capacitor design. The low-resistance integrated nMOS switches ensure high efficiency at heavy loads while minimizing critical inductances, making the layout a much simpler task with respect to discrete solutions.

The MAX15038 comes with a high-bandwidth (28MHz) voltage-error amplifier. The voltage-mode control architecture and the voltage-error amplifier permit a Type III compensation scheme to be utilized to achieve maximum loop bandwidth, up to 20% of the switching frequency. High loop bandwidth provides fast transient response, resulting in less required output capacitance and allowing for all-ceramic capacitor designs.

The MAX15038 provides two three-state logic inputs to select one of the nine preset output voltages. The preset output voltages allow users to achieve ±1% output-voltage accuracy without using expensive 0.1% resistors. In addition, the output voltage can be set to any custom value by either using two external resistors at the feedback with a 0.6V internal reference or applying an external reference voltage to the reference input (REFIN). The MAX15038 offers programmable soft-start time using one capacitor to reduce input inrush current.


  • Internal 31mΩ RDS(ON) high-side and 24mΩ RDS(ON) low-side metal-oxide semiconductor field-effect transistors (MOSFETs)
  • Continuous 4A output current over temperature
  • ±1% output accuracy overload, line, and temperature
  • Soft-start reduces inrush supply current
  • 500kHz to 2MHz adjustable switching frequency
  • Monotonic startup for safe-start into prebiased outputs
  • Selectable forced PWM or skip mode for light-load efficiency
  • Overcurrent and overtemperature protection
  • Output current sink/source capable with cycle-by- cycle protection
  • Open-drain power-good output


Designed, Built, Tested

Board pictured here has been fully assembled and tested. Not available for sale.



PCB Layout

Test Results

Maxim Devices (1)

Part Number Name Product Family Order Design kits and evaluation modules
MAX15038 4A, 2MHz Step-Down Regulator with Integrated Switches Switching Regulators Buy Now Design Kits

Maxim Devices (1)

Part Number Product Family
Switching Regulators
4A, 2MHz Step-Down Regulator with Integrated Switches

Design Files (4)

Title Type Size Date
maxrefdes1120-bom CSV 3KB 2020-12-07
maxrefdes1120-pcb PDF 562KB 2020-12-07
maxrefdes1120-schematic PDF 15KB 2020-12-07
TTS MAXREFDES Test Results Template_Rev 0_0318 PDF 304KB 2020-12-07
Date Type


(CSV, 3KB)



(PDF, 562KB)



(PDF, 15KB)


TTS MAXREFDES Test Results Template_Rev 0_0318

(PDF, 304KB)

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