QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 728
1MHZ SYNCHRONOUS STEP-UP DC/DC CONVERTER
1
LTC3458EDE
DESCRIPTION
Demonstration circuit 728 is a 1MHz Synchronous Step-
Up DC/DC Converter featuring the LTC
®
3458EDE. The
demo circuit demonstrates a DC/DC boost converter,
with a 1.5A switch, providing 7V at 200mA to 800mA
depending on input voltage. The circuit demonstrates
the advantages of output disconnect and inrush current
limiting. Small circuit size and low component count
make the LTC3458 suitable for use in many space-
conscious applications such as handheld instruments,
point-of-load converters, USB
V
BUS
Power and OLED
displays. Other integrated features include externally
programmable burst mode threshold, peak current limit,
soft-start, anti-ringing control and thermal shutdown.
NOTE: If supply is going to be used in
Fixed Frequency
Mode
, use a 50K Ohm resistor to tie the Burst pin to the
output voltage.
Design files for this circuit board are available. Call
the LTC factory.
LTC is a registered trademark of Linear Technology Corporation
Table 1.
Performance Summary (T
A
= 25°C)
PARAMETERS CONDITION VALUE
Minimum Input Voltage 2.0V
Maximum Input Voltage 6V
Output Voltage V
OUT
V
IN
= 2V, I
OUT
=200mA 7V ±3%
Output Voltage V
OUT
V
IN
= 2.7V, I
OUT
=300mA 7V ±3%
Output Voltage V
OUT
V
IN
= 3.3V, I
OUT
=400mA 7V ±3%
Output Voltage V
OUT
V
IN
= 4.2V, I
OUT
=550mA 7V ±3%
Output Voltage V
OUT
V
IN
= 5V, I
OUT
=700mA 7V ±3%
Output Voltage V
OUT
V
IN
= 6V, I
OUT
=800mA 7V ±3%
Typical Output Ripple V
OUT
V
IN
= 3.3V, I
OUT
= 400mA 20mV
P–P
Typical efficiency V
IN
=4.2V , I
OUT
= 300mA 87.5%
C9 used only when operating supply with long inductive input leads.
QUICK START PROCEDURE
Demonstration circuit 728 is easy to set up to evaluate
the performance of the LTC3458EDE. Refer to Figure 1
for proper measurement equipment setup and follow the
procedure below:
NOTE:
When measuring the input or output voltage rip-
ple, care must be taken to avoid a long ground lead on
the oscilloscope probe. Measure the input or output
voltage ripple by touching the probe tip directly across
the Vin or Vout and GND terminals. See Figure 2 for
proper scope probe technique.
1.
Place jumpers in the following positions:
On, JP2 Auto On.
