QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 1158A
MONOLITHIC SYNCHRONOUS BUCK REGULATOR
2
voltage set by the shunt jumper in XJP2, XJP3
or XJP4.
5. Vary the input voltage between 2.5V and
5.5V and the output voltage should be /-
0.4% tolerance.
6. Vary the V
OUT
load current from 0 to 1.25A,
and the output voltage should be within a toler-
ance of +/- 0.5%.
Warning - If the power for the demo board is car-
ried in long leads, the input voltage at the part
could “ring”, which could affect the operation of
the circuit or even exceed the maximum voltage
rating of the IC. To eliminate the ringing, insert a
small tantalum capacitor (for instance, AVX part
# TAJW686M010) on the pads between the in-
put power and return terminals on the bottom of
the demo board. The (greater) ESR of the tanta-
lum will dampen the (possible) ringing voltage
due to the use of long input leads. On a normal,
typical PCB, with short traces, the capacitor is
not needed.
Figure 1. Measuring Input or Output Ripple
Figure 2. Equipment setup to test LTC3564
LOAD
VOUT
V
VIN
A
+
_
+
_
+
_
+
_
A
+
_
V
+
_
