1

dc1617af

DEMO MANUAL DC1617A

DESCRIPTION

LTC3855EFE

Dual Output Synchronous

Buck Converter

Demonstration circuit DC1617A is a dual output synchro-

density, two sided drop-in layout with power components

on the top and the control circuit on the bottom. The pack-

age style for the LTC3855EFE is a 38-lead TSSOP.

The board comes in two assembly types. The –A assembly

provides 2.5V/15A and 1.8V/15A from a 4.5V to 26V input.

DCR inductor sensing is used to provide the highest ef-

ficiency. The current limit is NTC compensated to provide

the minimal amount of variation over temperature. The –B

assembly is a high power, 12V/6A and 5V/10A converter

with a 13V to 36V input. A sense resistor is used to provide

a precise current limit.

The main features of the board are listed below:

3.3V.

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

PERFORMANCE SUMMARY

• Optional resistors for single output dual phase opera-

tion.

• PLLIN pin for synchronization to an external clock

which can be used in conjunction with PHASMD pin

and CLKOUT pin for up to 12-phase operation.

• Selectable light load operating modes of pulse skip,

• TRACK/SS pins for external rail tracking.

• RUN pins and PGOOD pins for each phase.

Design files for this circuit board are available at

http://www.linear.com/demo

–A Assembly

PARAMETER

CONDITIONS

VALUE

Minimum Input Voltage

4.5V

Maximum Input Voltage

26V

2.5V ±2%

1.8V ±2%

15A

15A

Nominal Switching Frequency

250kHz

Efficiency, See Figure 3

93.0% Typical

91.7% Typical