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dc1901af
DEMO MANUAL DC1901A
DESCRIPTION
LTC3639EMSE
High Efficiency 150V, 100mA
Synchronous Buck Converter
Demonstration circuit 1901A is a 150V input, 100mA
output DC/DC power supply featuring the LTC3639. The
IC operates in a high efficiency Burst Mode
®
operation
and includes internal high and low side power MOSFETs.
The board will accept an input voltage between 4V and
150V, and provide jumper selected output voltages of
1.8V, 3.3V, 5V and an option for additional voltages. The
IC includes internal soft-start and a provision for increas-
ing soft-start time.
Included on the board is an ON/OFF jumper that can also
be configured as a precision undervoltage lockout. Ad-
ditional PC pads are included for programming current
limit to optimize efficiency and for reducing output voltage
ripple and reducing component size. A terminal (FBO)
L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
PERFORMANCE SUMMARY
is included to allow multiple boards to be paralleled for
higher output current.
Output voltage between 800mV and V
IN
can be programmed
using optional resistors. (Higher voltage rating output
capacitors may be required.)
The LTC3639 data sheet gives a complete description of the
IC operation and application information. The data sheet
must be read in conjunction with this quick start guide.
Design files for this circuit board are available at
http://www.linear.com/demo
Specifications are at T
A
= 25°C
PARAMETER CONDITION VALUE
Input Voltage Range 4V to 150V
1.8V Output Voltage V
IN
= 12V, I
OUT
= 0A to 100mA 1.8V ±2%
3.3V Output Voltage V
IN
= 12V, I
OUT
= 0A to 100mA 3.3V ±2%
5V Output Voltage V
IN
= 12V, I
OUT
= 0A to 100mA 5V ±2%
Maximum Output Current, I
OUT
V
IN
= 4V to 150V, V
OUT
= 1.8V, 3.3V or 5V 100mA
Typical Efficiency V
IN
= 12V, V
OUT
= 5V, I
OUT
= 100mA 87.3%
Typical Output Ripple V
IN
= 150V, V
OUT
= 5V, I
OUT
= 100mA (20MHz BW) 66mV
P-P
