SM8172A Datasheet, PDF (14/17 Pages) Nippon Precision Circuits Inc – 2-output Power Supply IC

SM8172A
14. USAGE NOTES
14-1. Select of Inductance (L)
It recommends 2.2µH of Inductance (L) for SM8172A. Since the DC resistance of inductance affects the
power efficiency, we recommend the inductance of low DC resistance. Besides, please take care so that the
inductance peak current (Ipeak) does not exceed the maximum allowable current of inductor.
14-2. External Capacitor Type
The external capacitors connected to the SM8172A should be multi-layer ceramic capacitors, with low temper-
ature coefficient X5R or X7R class (EIA standard) multi-layer ceramic capacitors recommended. Use of high
temperature coefficient Z5U or Y5V class multi-layer ceramic capacitors may cause an unstable output voltage
condition and should be avoided.
Capacitor temperature coefficient 3-letter codes (EIA standard)
Lower category
temperature
X = −55°C
Y = −30°C
Z = +10°C
Upper category
temperature
5 = +85°C
6 = +105°C
7 = +125°C
8 = +150°C
Maximum deviation in capacitance
from +25°C (0V DC) value
F = ± 7.5%
P = ± 10%
R = ± 15%
S = ± 22%
T = +22%/−33%
U = +22%/−56%
V = +22%/−82%
Selection
: X5R characteristics
14-3. VIN Supply Input Capacitor
In some cases, the printed board component layout may affect the stability of the output voltages. In such
cases, the VIN power supply capacitor should be increased or an additional capacitor connected.
SEIKO NPC CORPORATION —14