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 Regulator - Switching Regulators Buy Now Design Kits

Maxim Devices (1)

Part Number Product Family
Switching Regulator - 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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