QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 627
BOOST CONVERTER
LT3461 / LT3461A
DESCRIPTION
Demonstration circuit 627 features the LT3461 /
LT3461A in a 12.0V output boost converter which
operates from an input voltage of 3V to 6V. The
maximum output current is 70mA when powered
from a 5.0V input and 40mA when powered from a
3.3V input. A soft-start option is provided by the
SHDN pin and can be configured with an on-board RC
filter.
The internal schottky of the LT3461 / LT3461A re-
duces part count and the high switching frequency
allows the use of a small SMT inductor and output
capacitors. The small size of the circuit makes it ideal
for space-sensitive applications.
Table 1. Performance Summary (T
A
= 25°C)
PARAMETER
LT Part
Minimum Input Voltage
Maximum Input Voltage
Output Voltage V
OUT
Maximum Output Current
V
IN
= 3V to 6V
V
IN
= 3.3V
V
IN
= 5.0V
Typical Efficiency
Typical Output Voltage Ripple
(20MHz BW)
Nominal Switching Frequency
V
IN
= 3.3V, I
OUT
= 40mA
V
IN
= 5.0V, I
OUT
= 70mA
V
IN
= 3.3V, I
OUT
= 40mA
V
IN
= 5.0V, I
OUT
= 70mA
CONDITION
DC627A-A
VALUE
LT3461ES6
3V
6V
12V ±4%
40mA
70mA
79%
83%
20mV
P–P
28mV
P–P
1.3MHz
DC627A-B
VALUE
LT3461AES6
3V
6V
12V ±4%
40mA
70mA
76%
81%
9mV
P–P
12mV
P–P
3.0MHz
The DC627A comes in two versions. The “-A” version
uses the LT3461 and the “-B” version uses the
LT3461A.
Design files for this circuit board are available. Call
the LTC factory.
LT is a trademark of Linear Technology Corporation
QUICK START PROCEDURE
Demonstration circuit 627 is easy to set up to evalu-
ate the performance of the LT3461 or LT3461A. Refer
to Figure 1 for the proper measurement equipment
setup and follow the procedure below:
1.
Place jumper JP1 in the “ON” position if not al-
2.
With power off, connect the input power supply.
3.
Turn on the input power source and set it to 3.3V.
The output should be 12.0V ±4% at no load.
4.
Connect the load from VOUT to GND and set to
ready done.
40mA. The output should still be 12.0V ±4%.
1
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 627
BOOST CONVERTER
5.
Increase the input voltage to 5.0V and apply 70mA
a.
For the DC627A-A, the frequency should be be-
load and re-check regulation.
6.
Measure the DC input current at V
IN
= 5.0V and
tween 1.0MHz and 1.7MHz.
b.
For the DC627A-B, the frequency should be be-
I
OUT
= 70mA.
a.
For the DC627A-A, the input current should be
tween 2.1MHz and 3.9MHz.
NOTE:
If this circuit will be used in a hot plug applica-
less than 215mA.
b.
For the DC627A-B, the input current should be
less than 225mA.
7.
Monitor the output voltage ripple. Refer to Figure 2
for the proper measurement technique.
8.
Measure the output ripple frequency.
tion, then be sure to measure the inrush current. The
maximum non-repetitive surge current the internal
schottky can handle is 1.5A. The inrush current can
be monitored by measuring the current through the
inductor when V
IN
is initially applied. Refer to the data
sheet for more details.
Figure 1. Proper Measurement Equipment Setup
Figure 2. Measuring Input or Output Ripple
2
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 627
BOOST CONVERTER
3
Mouser Electronics
Authorized Distributor
Click to View Pricing, Inventory, Delivery & Lifecycle Information:
Analog Devices Inc.
:
DC627A-A DC627A-B
