1
dc1228af
DEMO MANUAL DC1228A
Description
LT3573
Isolated Monolithic
Flyback Converter
Demonstration circuit 1228A is an isolated flyback con-
verter featuring the
LT
®
3573
. This demo circuit is designed
for a 5.0V output from a 10V to 30V input. The maximum
output current is 1A when the input voltage is higher than
20V. No third winding or opto-isolator is required for
regulation. The part senses the isolated output voltage
directly from the primary-side flyback waveform.
The LT3573 operates with input supply voltages from 3V
to 40V, and can deliver an output power up to 7W with
no external power devices. The LT3573 utilizes bound-
ary mode operation to provide a small magnetic solution
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
with improved load regulation. The LT3573 can be used
in industrial, automotive and medical applications where
an isolated output is required.
The LT3573 data sheet gives a complete description of
the part, operation and application information. The data
sheet must be read in conjunction with this quick start
guide for demonstration circuit 1228A.
Design files for this circuit board are available at
http://www.linear.com/demo/DC1228A
Specifications are at T
A
= 25°C
PARAMETER
CONDITION
MIN
TYP
MAX
UNITS
Input Voltage Range
10
30
V
Output Voltage V
OUT
V
IN
= 10V to 30V
4.75
5
5.25
V
Maximum Output Current I
OUT
V
IN
= 10V to 20V
V
IN
= 20V to 30V
0.7
1.0
A
A
Switching Frequency
V
IN
= 12V, I
OUT
= 0.7A
V
IN
= 24V, I
OUT
= 1A
169
238
kHz
kHz
Voltage Ripple V
OUT
V
IN
= 24V, I
OUT
= 1A
100
mV
Efficiency
V
IN
= 24V, I
OUT
= 1A
84
%
