1
dc1480af
DEMO MANUAL DC1480A
DESCRIPTION
LTC3865EUH-1
Dual 5A Synchronous Buck
Converter with Pin Selectable Outputs
Demonstration circuit 1480A is a dual output synchronous
buck DC/DC converter featuring the LTC
®
3865EUH-1. The
input voltage range is from 4.5V to 14V. The outputs are
3.3V/5A and 1.8V/5A. Each output voltage can be precisely
programmed to a preset value within 1% error with the
VID pins. The demo board uses a high density, two sided
drop-in layout. The package of LTC3865EUH-1 is a small,
low thermal impedance 5mm × 5mm 32-Lead QFN.
The light load operation mode of the converter is de-
termined with the MODE/PLLIN pin. Use JP1 jumper to
select Burst Mode
®
operation, pulse-skipping mode or
L
, LT, LTC, LTM, Linear Technology, Burst Mode and the Linear logo are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
PARAMETER
CONDITION
VALUE
Input Voltage Range
4.5V to 14V
Output Voltage, V
OUT1
V
IN
= 4.5V to 14V, I
OUT1
= 0A to 5A
3.3V ±1%
Output Voltage, V
OUT2
V
IN
= 4.5V to 14V, I
OUT2
= 0A to 5A
1.8V ±1%
Maximum Output Current, I
OUT1
V
IN
= 4.5V to 14V, V
OUT1
= 3.3V
5A
Maximum Output Current, I
OUT2
V
IN
= 4.5V to 14V, V
OUT2
= 1.8V
5A
Typical Full Load Efficiency, Channel 1
V
IN
= 12V, V
OUT1
= 3.3V, I
OUT1
= 5A
91.6%
Typical Full Load Efficiency, Channel 2
V
IN
= 12V, V
OUT2
= 1.8V, I
OUT2
= 5A
86.6%
Typical Switching Frequency
500kHz
PERFORMANCE SUMMARY
forced continuous mode operation. Switching frequency
is preset at about 500kHz. This frequency can be modi-
fied by changing R5 value at the FREQ pin. The converter
can also be externally synchronized from 250kHz to
770kHz through MODE/PLLIN pin (SYNC terminal on the
board). To shut down a channel, force its RUN pin below
1.2V (Jumper: OFF). The power good output (PGOOD1
or PGOOG2 terminal) is low when that channel output
exceeds ±10% regulation window.
Design files for this circuit board are available at
(T
A
= 25°C)