MAXREFDES1269: 5V/20A, synchronous buck converter using MAX20098

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.

特征

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