S1F78100Y2A Epson Electronics America, Inc., S1F78100Y2A Datasheet - Page 179

• Manufacturer Part Number: S1F78100Y2A
• Description: High Precision Voltage Regulators
• Manufacturer: Epson Electronics America, Inc.

S1F71100 Series
S1F71100 Series PWM Type Step-down DC/DC Switching Regulator
DESCRIPTION
S1F71100 is a pulse width modulation (PWM) type
step-down DC/DC converter control IC for which the
CMOS process is used and to which a power transistor
is connected outside. S1F71100 is composed of an os-
cillator, a reference voltage circuit, an error amplifier, a
PWM circuit, a soft start circuit, a driver, etc. When this
IC drives an external P ch power MOS transistor,
S1F71100 can constitute a step-down DC/DC converter
that converts input voltages up to 12V into the output
voltage of 3.3V.
S1F71100 is also provided with a low-voltage protec-
tion circuit, an overcurrent protection circuit and a soft
start protection circuit. When receiving external sig-
nals, S1F71100 can stop the oscillator and the switching
circuit and turn off the power, so that it can reduce
wasteful current consumption at the time of system halt.
BLOCK DIAGRAM
4–34
ERCAP
SSCAP
POFFX
V
O
Error amplifier
voltage circuit
+
–
Reference
Soft start
Oscillator
V
V
SS
EPSON
PWM circuit
DD
Low-voltage
protection circuit
FEATURES
• Input voltage : 3.3V ~ 12V
• Output voltage : 3.3V (S1F71100M0A0)
• Power off current : 1 A
• Self current consumption : 800 A
• Frequency fixing (200kHz) PWM
• Power off function (IC shutdown)
• Soft start function
• Overcurrent protection function
• Low-voltage protection function
• Shipping pattern : plastic package SOP4-8pin
* Radiation-resistant design has not been provided for
this specification.
+
–
protection circuit
Overcurrent
–
+
Driver
Technical Manual
S1F70000 Series
I
SWO
SENSE