S-8331 Seiko Instruments USA, S-8331 Datasheet - Page 22

• Manufacturer Part Number: S-8331
• Description: Step-Up Switching Regulator (DC/DC Converter ICs)
• Manufacturer: Seiko Instruments USA

22
STEP-UP, FOR LCD BIAS SUPPLY, 1-CHANNEL SWITCHING REGULATOR
S-8330/8331 Series
Figure 14 shows a circuit example using the 2SK2159 manufactured by NEC Electronics Corporation
as a MOS FET transistor (Nch). Use an Nch power MOS FET as a MOS FET. The EXT pin in the S-
8331 series can drive a MOS FET with approx.1000 pF gate capacitance. The ON reisistor of the MOS
FET depends upon a difference between voltage input voltage V
FET and thereby affects the output amperage and the efficiency. The gate voltage and the current of
the MOS FET are supplied by input voltage V
that the IC will not function if the threshold voltage of the MOS FET is higher than the input voltage.
5.2 Enhancement MOS FET type
V
IN
Figure 14 Circuit Example Using the 2SK2159
L
EXT
V
SS
RESET
Seiko Instruments Inc.
2SK2159
SBD
IN
. So pay attention if the input voltage is low. Also note
V
ON/OFF
OUT
ZD:15V
R
A
IN
2SJ356
and the threshold voltage of the MOS
R
M
B
N
+
−
CL
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