DESCRIPTION

Demonstration circuit 2879A is a high efficiency, high

power density hybrid converter. It can deliver 12V/25A

with an input voltage from 36V to 60V (up to 65V during

transients). This demo board features the LTM®4660,

which uses an architecture that merges soft-switching

switched capacitor topology with a traditional step-down

converter to provide superior efficiency compared to the

traditional switching architectures. It offers a high efficiency/

high density and cost effective solution for nonisolated

intermediate bus applications in power distribution,

datacom and telecom.

Due to its current mode control architecture, multiple

LTM4660s can be operated in a parallel, multiphase configuration

with excellent current sharing and low output

voltage ripple to enable much higher power applications.

Other benefits include low EMI emissions due to a softswitched

front end and reduced MOSFET stress.

The LTM4660 design eliminates the inrush current typically

associated with switched capacitor circuits by prebalancing

the capacitors on start-up. The LTM4660 also

monitors system voltage, current and temperature for

faults. It stops switching and pulls the FAULT pin low

when a fault condition occurs. An onboard timer can be

set for appropriate restart/retry times.

Additional features include ±1.5 output voltage accuracy

over temperature, a clock output for multiphase

operation, a power good output signal, short-circuit protection,

monotonic output voltage start-up, optional external

reference, undervoltage lockout and internal charge

balance circuitry.

The LTM4660 data sheet must be used in conjunction

with this demo board manual.