1
dc1632af
DEMO MANUAL DC1632A
DESCRIPTION
LTC3839EUH
Fast Transient
Step-Down DC/DC Converter
Demonstration circuit 1632A is a single output 1.5V/40A
dual phase synchronous buck converter operating with
a switching frequency of 300kHz over an input voltage
range of 4.5V to 14V. The controlled on-time valley current
mode architecture of the LTC3839 allows for a fast load
step response (see Figure 4). The load step response can
be tested with the on-board load step circuit and a bench
pulse generator.
Other features of the board include remote sensing, sel-
ectable light load operating modes of forced continuous
mode (FCM) and discontinuous mode (DCM), a PLLIN
pin for synchronizing to an external clock, a CLKOUT
pin, an EXTV
CC
pin to reduce losses in the controller, and
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
RUN and TRACK/SS pins. Up to 12-phase operation can
be achieved by daisy-chaining the CLKOUT and PLLIN
signals of multiple boards and programming the relative
phase with the PHASMD jumper.
The demo board uses a high density, two sided drop-in
layout. The entire converter, excluding the bulk output and
input capacitors, fits within a compact 1.6˝
×
1.2˝ area
on the board. The package style for the LTC3839EUH is a
32-lead 5mm
×
5mm QFN with an exposed ground pad.
Design files for this circuit board are available at
http://www.linear.com/demo
(T
A
= 25°C)
PARAMETER
CONDITIONS
VALUE
Minimum Input Voltage
4.5V
Maximum Input Voltage
14V
Output Voltage V
OUT
I
OUT
= 0A to 40A, V
IN
= 4.5V to 14V
1.5V ± 2%
V
OUT
Maximum Output Current, I
OUT
V
IN
= 4.5V to 14V, V
OUT
= 1.5V
40A
Nominal Switching Frequency
300kHz
Efficiency (see Figures 2 and 3)
V
OUT
= 1.5V, I
OUT
= 40A, V
IN
= 12V
90.7% Typical
Downloaded from
