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Microchip MIC2128 75 V Synchronous Buck Controller

Featuring adaptive ON-time control and external soft start

The Microchip MIC2128 is a constant-frequency synchronous buck controller group featuring a unique adaptive ON-time control architecture.

Operating over an nput voltage range from 4.5V to 75V, the MIC2128 can be used to supply load current up to 25A (thermally limited). The output voltage is adjustable down to 0.6V with a guaranteed accuracy of ±1%. The device operates with programmable switching frequency from 270kHz to 800kHz.

Microchip’s MIC2128 offers a full suite of protection features to ensure protection of the IC during fault conditions. These include undervoltage lockout to ensure proper operation under power-sag conditions, adjustable soft-start to reduce inrush current, "hiccup" mode short-circuit protection, and thermal shutdown.


  • Hyper Speed Control® architecture enables:
    • High input to output voltage conversion ratio capability
    • Any Capacitor™ stable
    • Ultra-fast load transient response
  • 4.5V to 75V input voltage
  • Adjustable output voltage from 0.6V to 30V
  • 270kHz to 800kHz programmable switching frequency
  • Externally programmable soft start


  • Enable input and power good output
  • Built-in 5V regulator for single-supply operation
  • Auxiliary bootstrap LDO
  • Internal bootstrap diode
  • Programmable current limit and "hiccup" mode short-circuit protection
  • Internal compensation, and thermal shutdown
  • Supports safe start-up into a pre-biased output
  • -40°C to +125°C junction temperature range
  • Available in 16-pin 3mm x 3mm QFN package