SM8131B View Datasheet(PDF) - Nippon Precision Circuits
Part Name
Description
MFG CO.
'SM8131B' PDF : 21 Pages View PDF
SM8131B
PERIPHERAL PARTS
About the External Capacitors
The best capacitors for use with the SM8131B are multi-layer ceramic capacitors. When selecting a multi-layer
ceramic capacitor, only X5R and X7R dielectric types are strongly recommended, since the loss of capacitance
in various conditions is less than other types such as Z5U and Y5V. The much loss of capacitance in various
conditions may cause the output voltage unstable.
Table. The EIA three digit "TC" code
Lower temperature limit
X = − 55°C
Y = − 30°C
Z = + 10°C
High temperature limit
5 = + 85°C
6 = + 105°C
7 = + 125°C
8 = + 150°C
Maximum allowable capacitance
change from + 25°C (0V DC)
F = ± 7.5%
P = ± 10%
R = ± 15%
S = ± 22%
T = + 22%/− 33%
U = + 22%/− 56%
V = + 22%/− 82%
For example
: X5R
About the Input Capacitor "C4"
The parts layout of PCB may merely cause the “VOUT” output voltage unstable. In this case, increasing the
“C4” input capacitance value or adding another capacitor on the VIN input line is effective to solve the unsta-
ble output voltage.
About the LED Current Setting Resistor "RSET"
The LED drive current variation depends on the LED drive current setting resistor “RSET” variation. There-
fore, a precise resistor is recommended for RSET. The ISET output current value is about 20µA, so a 1/10 watt
class resistor is acceptable as the RSET.
NIPPON PRECISION CIRCUITS INC.—15
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