QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 545
MICROPOWER STEP-UP SWITCHING REGULATOR IN SC-70
1
LT3460ESC6
DESCRIPTION
Demonstration circuit 545 features the LT3460, step-up
DC/DC converter with 1.3MHz constant frequency in a SC70
package. There are two switching regulator circuits in
DC545. The 12V output boost converter (upper circuit) is de-
signed to convert 5V input to 12V output at 70mA of load
current and the SEPIC converter (lower circuit) is designed to
convert 10V ~ 16V input to 12V at 50mA.
Each circuit has a jumper for testing SHDN mode operation.
Placing the jumper (JP1 & JP2) to “Hi” enables LT3460 op-
eration and placing the jumper to “Lo” disables the LT3460
and the converter will turn off.
Design files for this circuit board are available. Call the LTC
factory.
Table 1. Performance Summary
PARAMETER CONDITION
VALUE
Input Voltage
Boost Converter
SEPIC Converter
5V
10V ~ 16V
Maximum Output Current
Boost Converter
SEPIC Converter
70mA
50mA
V
OUT
REG Boost
Converter
SEPIC Converter
≅
250mV
≅
200mV
QUICK START PROCEDURE
12V OUTPUT BOOST CONVERTER (UPPER CIRCUIT)
Refer to Figure 1 for proper measurement equipment setup and follow the procedure below:
1. Connect the input power supply (set at 5V) to
Vin
and
GND
pins of the
boost converter
.
2. Turn on the input power supply and observe the
output voltage, the output voltage should read
≅
12V
3. Turn on the load preset at
70mA
. The input cur-
rent should read around
≅
200mA and the output
voltage should be 12.1V
±
0.25V.
4. Check the output ripple using the oscilloscope (re-
fer to Figure 3). The output ripple should not be
greater than 60mV. Also check the switching fre-
quency, it should be
≅
1.3MHz.
