DC2117A

Demonstration circuit 2117A is a single output high voltage nonisolated synchronous step-down converter that drives all N-channel MOSFET power stage. It features the LTC3895EFE, a high voltage step-down DC/DC controller housed in a TSSOP-38 package with several pins removed for high voltage spacing. This DC2117A operates over an input voltage range from 14V to 130V, while the LTC®3895 can operate up to 150V. This demo board produces a 12V output voltage with up to a 5A output current, and is configured with a sense resistor for over current protection and has optional DCR sensing. To prevent high on-chip power dissipation in high input voltage applications, the LTC3895 includes an NDRV pin which drives the gate of an optional external N-channel MOSFET acting as a low dropout linear regulator to supply IC power and is an option on this board. An internal charge pump allows for 100% duty cycle operation in dropout, a useful feature when powered from battery during discharge.

• Default operating frequency (typical) of 150KHz
• External clock sync frequency range from 75KHz to 850KHz
• Typical full load efficiency of 94.9% (VIN = 48V, VOUT = 12V, IOUT = 5A, fSW = 150KHz)

Notes

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