S-8340A25AFT-T2-X Datasheet, PDF (25/55 Pages) Seiko Instruments Inc – SWITCHABLE SWITCHING REGULATOR CONTROLLER

STEP-UP, 600 kHz, PWM CONTROL OR PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.4.0_01
S-8340/8341 Series
(2) Using Bipolar Transistor
L
V IN
NPN
B ip olar
T rans is tor
R SENSE
Cb
EXT
Rb
SENSE
SD
VDD
V OUT
Triangular w ave
oscillation circuit
PW M comparator
Phase
com pensation
circuit
IC internal power
supply
VOUT
RS
CS
120 mV
Shutdown
circuit
PW M, PW M/PFM
switching control
circuit
Soft-start
circuit
CC
R1
Error am plifier
R2
VREF =1.0 V
V o lta ge /c ur r e nt
reference
+
CL
VSS
O N /O F F
CSS
CSS
CVREF
C VREF
Single ground
Figure 16 Output Voltage Fixed Output Type
L
VIN
NPN
Bipolar
T rans is tor
R SENSE
Cb
EXT
Rb
SENSE
SD
Triangular w ave
oscillation circuit
PW M comparator
VDD
Phase
com pensation
circuit
IC internal pow er
supply
V O UT
RS
CS
120 mV
Shutdown
circuit
PW M, PW M/PFM
switching control
c ir c uit
Soft-start
circuit
Error am plifier
VREF =1.0 V
V o lta ge /c ur r e nt
reference
CFB
RFB1
+
FB
CL
RFB2
VSS
ON/OFF
CSS
CSS
CVREF
C VREF
Single ground
Figure 17 Output Voltage External Setting Type
Caution The above connection and constant will not guarantee successful operation. Perform thorough
evaluation using the actual application to set the constant.
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