EN5367QI
Evaluation Board User Guide
Jan. 2012
Page 7 of 8
Test Recommendations
Recommendations
To guarantee measurement accuracy, the following precautions should be observed:
1. Make all input and output voltage measurements at the board using the test
points provided (TP18 to TP21). This will eliminate voltage drop across the
line and load cables that can produce false readings.
2. Measure input and output current with series ammeters or accurate shunt
resistors. This is especially important when measuring efficiency.
3. Use a low-loop-inductance scope probe tip shown below to measure
switching signals and input / output ripple to avoid noise coupling into the
probe ground lead. Input ripple, output ripple, and load transient deviation are
best measured near the respective input / output capacitors. For more
accurate ripple measurement, please see Enpirion App Note regarding this
subject.
4. The board includes a pull-up resistor for the POK signal and ready to monitor
the power OK status at clip lead marked POK.
5. A 47nF soft-start capacitor is populated on the board for ~3msec soft-start
time.
6. The over-current protection circuit typically limits the maximum load current to
approximately 1.5X the rated value.
Bill of Materials
Designator
Qty
Description
C1, C2, C16
3
CAP, 0.1UF 10V X7R 0402 10%
C3, C7
2
CAP, 10UF 0805 X7R 10% 10V CERAMIC
C4, C10
2
CAP, 47000PF 50V X7R 0805
C5, C6
2
CAP, 47UF 10V X5R 1206, CERAMIC
C9
1
CAP, CERAMIC 18PF 5% 50V NP0 0805
C13
1
CAP, 150UF 20% 10V ALUMINUM ELECTROLYTIC
C8, C11, C12, C14,
C15, C17, C18, J7,
R6, R9-R13
14
NOT USED
D1 1
S2A
DIODE
FB1
1
SMT FERRITE BEAD 4000MA 0805 (Wurth Electronik 742792012)
J1
1
CONNECTOR, CUSTOM, VERTICAL HEADER, SMT
J2
1
CONNECTOR HEADER 8POS. 100” STR TIN (Molex 90131-0124)
J3-J6
4
BANANA JACK (Keystone 575-4)
