QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1242A
600MA SYNCHRONOUS BOOST DC/DC CONVERTER AND 100MA LDO REGULATOR
2
Figure 1. Demonstration Circuit Test Setup
V
Input
Power
Supply
A
+
-
V
A
Resistive
Loads
V
V
A
V
PWRGOOD
STATUS Outputs
Low BAT
STATUS Outputs
Note:
resistors can
be replaced
with LEDs
Select LDO
input supply
Select
STATUS
power
source
EXT. STATUS
power source input,
select with JP4
BOOST
LDO
LDO Input
Select
LOW
BAT
threshold
Select BOOST
ON/OFF/SEQ
Select
LDO
ON/OFF
or SEQ
Select
PWM
or BURST
Mode
LDO & BOOST
ON/OFF Inputs
Select VOUT
BOOST Regulator
Select VOUT
LDO Regulator
or
BOOST Converter Input
QUICK START PROCEDURE
The LTC3537 circuit can be evaluated using
the setup shown in Figure 1. Most of the fea-
tures can be verified simply by placing jump-
ers in various locations. It is recommended
that the LTC3537 data sheet be nearby for a
more complete explanation of the various fea-
tures and specifications.
Using jumpers JP5 and JP6, select the de-
sired output voltages (with no jumpers in-
stalled, the output voltages are set for the
highest voltage). Enable each regulator by
placing jumpers JP7 and JP8 in the ON posi-
tion and place the “LDO IN” jumper (JP3) to
the “VINB” (center) position which parallels
the LDO and BOOST supply inputs. Set the
“STATUS PWR” jumper (JP4) to the “VOUTB
position, which connects the open-drain
power good outputs and the low battery out-
put pull-up resistors to the output of the boost
regulator. JP4 also allows an external voltage
applied to the STATUS PWR IN terminal to be
used for the pull-up resistors.
Connect voltmeters and ammeters as shown
in the Figure 1 test setup. Connect a power
supply to the VINBOOST and GND terminals
and a suitable load resistor between VOUT
BOOST and GND. Avoid excessive wire
lengths between the input power supply and
the demonstration board. Wire lengths greater
than 18 inches may require additional capaci-
tance near the input terminals.
With a light load (1k resistor) at the output,
begin increasing the input power supply volt-
age. At approximately 700mV, the output will
rise to the selected regulated voltage. When
the output voltage exceeds the input voltage
by at least 240mV, the converter powers itself
from the output instead of the input. This fea-
ture allows the input voltage to drop as low as
500mV (at light loads) and still maintain a
