S-8540A15FN-IAAT2Z Datasheet, PDF (2/36 Pages) Seiko Instruments Inc – SWITCHABLE SWITCHING REGULATOR CONTROLLER

STEP-DOWN, 600 kHz PWM CONTROL or PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8540/8541 Series
Rev.4.0_01
 Block Diagrams
1. A, C types (fixed output voltage)
Pch Power
MOS FET
V_IN
L
VIN
Power for IC
Triangular wave
oscillation circuit
EXT
PWM comparator
SENSE
Phase
compensation
circuit
SD
C_IN
Error amplifier
PWM or PWM / PFM
switching control
circuit
Shutdown soft start
circuit
VREF=1.0 V
Voltage/current
reference
R_SENSE
125 mV
VOUT
C_OUT
VSS
ON/OFF
RSS
C_SS
VON/OFF
Figure 1
CVREF
C_VL
2. B, D types (feed back)
Pch Power
MOS FET
V_IN
L
VIN
Power for IC
Triangular wave
oscillation circuit
EXT
PWM comparator
SENSE
Phase
compensation
circuit
SD
C_IN
Error amplifier
PWM or PWM / PFM
switching control
circuit
Shutdown soft start
circuit
VREF=1.0 V
Voltage/current
reference
RSENSE
125 mV
VOUT
CFB
FB
VSS
VOUT
R_A
C_OUT
RB
ON/OFF
R_SS
C_SS
VON/OFF
Figure 2
CVREF
C_VL
2