S-8540 SII [Seiko Instruments Inc], S-8540 Datasheet - Page 20

• Manufacturer Part Number: S-8540
• Description: STEP-DOWN, 600 kHz PWM CONTROL or PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
• Manufacturer: SII [Seiko Instruments Inc]

20
STEP-DOWN, 600 kHz PWM CONTROL or PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8540/8541 Series
Application Circuits
1. External adjustment of output voltage
The output voltage can be adjusted or changed in the output voltage setting range (1.5 to 6.0 V) by
adding
8540/8541D00AFN, as shown in Figure 15.
thermistor in series to R
Caution The above connection diagram and constant will not guarantees successful operation.
One point ground
V
IN
external resistors (R
Perform through evaluation using the actual application to set the constant.
Tr
A
SD
and R
C
B
A
IN
.
EXT
, R
VIN
B
Power for IC
ON/OFF
) and a capacitor (C
Shu tdo wn
circuit
Seiko Instruments Inc.
s of t start
Figure 15
T riangular wave
oscillation circuit
PWM comparator
Temperature gradient can be given by inserting a
PW M, PW M/PFM
switching control
circuit
V
ON/OFF
−
+
FB
Phase
comp ensation
circuit
Voltage/current
referenc e
) in the S-8540/8541B00AFN and S-
V
Error amplifier
RE F
L
=1.0 V
−
+
CVREF
SENSE
125m V
+
−
R
SEN SE
C
VSS
FB
VOUT
FB
Rev.3.2
R
R
A
B
C
OU T
_00