MAXREFDES1269: 5V/20A, Synchronous Step-Down Converter Using the MAX20098


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The MAXREFDES1269 demonstrates how to build a DC-DC buck converter using the MAX20098 step-down controller for 5V DC output applications from a 6V to 36V input. This reference design delivers up to 20A at 5V output. The design uses a six-layer board. Table above shows an overview of the design specification.

The MAX20098 is a 3.5V to 36V synchronous, step-down DC-DC controller. It uses a current-mode control architecture and can operate in the pulse-width modulation (PWM) or skip-mode control schemes. The device can operate in dropout conditions at a 99% duty cycle. The external sync pin (FSYNC) logic input, under light-load applications, allows the device to operate either in the skip-mode or fixed-frequency forced-PWM (FPWM) mode to minimize electromagnetic interference (EMI). The output voltage is programmable from 1V to 10V with fixed 3.3V/5V options. The feedback (FB) regulation is accurate within ±1% over -40°C to +125°C.


  • Efficiency = 88% at Full Load
  • Output-Voltage Ripple < 50mV across Line and Load Conditions
  • Overshoot < 150mV for 50% Load Step
  • Continuous Conduction Mode (CCM) Operation
  • Internal Soft-Start
  • Overall Solution Size = 572mm2


Designed, Built, Tested

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



PCB Layout

Test Results


Input Type Vin(Min) Vin(Max) Iout(Max) Single/Multiple Output Vout(V) Pout(W) Isolated/Non-Isolated Topology
DC 6 36 20 - 5 100 Non-Isolated Synchronous Buck


Input Type DC
Vin(Min) 6
Vin(Max) 36
Iout(Max) 20
Single/Multiple Output -
Vout(V) 5
Pout(W) 100
Isolated/Non-Isolated Non-Isolated
Topology Synchronous Buck

Maxim Devices (1)

Part Number Name Product Family Order Design kits and evaluation modules
MAX20098 Versatile Automotive 36V 2.2MHz Buck Controller with 3.5µA IQ Switching Regulators Buy Now Design Kits

Maxim Devices (1)

Part Number Product Family
Switching Regulators
Versatile Automotive 36V 2.2MHz Buck Controller with 3.5µA IQ

Design Files (5)

Title Type Size Date
maxrefdes1269-schematic PDF 16KB 2020-09-15
TTS MAXREFDES Test Results Template_Rev 0_0318 PDF 665KB 2020-09-15
maxrefdes1269-bom CSV 4KB 2020-09-15
maxrefdes1269-pcb PDF 1MB 2020-09-15
maxrefdes1269-bom XLSX 13KB 2020-09-15
Date Type


(PDF, 16KB)


TTS MAXREFDES Test Results Template_Rev 0_0318

(PDF, 665KB)



(CSV, 4KB)



(PDF, 1MB)



(XLSX, 13KB)

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