REGULATOR CONTROLLER. S-8541 Datasheet

S-8541 CONTROLLER. Datasheet pdf. Equivalent

Part S-8541
Description SWITCHING REGULATOR CONTROLLER
Feature S-8540/8541 Series www.ablicinc.com © ABLIC Inc., 2000-2010 STEP-DOWN, 600 kHz PWM CONTROL or PWM/.
Manufacture ABLIC
Datasheet
Download S-8541 Datasheet

Rev.3.2_00 www.DataSheet4U.com STEP-DOWN, 600 kHz PWM CONTR S-8541 Datasheet
S-8540/8541 Series www.ablicinc.com © ABLIC Inc., 2000-2010 S-8541 Datasheet
Recommendation Recommendation Datasheet S-8541 Datasheet





S-8541
S-8540/8541 Series
www.ablicinc.com
© ABLIC Inc., 2000-2010
STEP-DOWN, 600 kHz PWM CONTROL or PWM/PFM
SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.4.0_02
The S-8540/8541 Series is a family of CMOS step-down switching regulator controllers with PWM control (S-
8540 Series) and PWM/PFM switchover control (S-8541 Series). These devices consist of a reference voltage
source, oscillation circuit, an error amplifier, phase compensation circuit, PWM control circuit, current limit
circuit. A high efficiency and large current switching regulator is realized with the help of small external
components due to the high oscillation frequency, 300 kHz and 600 kHz.
The S-8540 Series provides low-ripple voltage, high efficiency, and excellent transient characteristics which
come from the PMW control circuit capable of varying the duty ratio linearly from 0 to 100%, the optimized error
amplifier, and the phase compensation circuit.
The S-8541 Series operates under PWM control when the duty ratio is 29% or higher and operates under PFM
control when the duty ratio is less than 29% to ensure high efficiency over all load range.
These controllers serve as ideal main power supply units for portable devices due to the high oscillation
frequencies together with the small 8-Pin MSOP package.
Features
Oscillation frequency
Output voltage
Output voltage precision
Feed back type for output voltage (FB)
External components:
Built-in PWM/PFM switchover control
circuit (S-8541 series)
Current limit circuit
Soft-start
Shutdown function
Lead-free, halogen-free*1
600 kHz (A, B types)
300 kHz (C, D types)
1.5 to 6.0 V, selectable in 0.1V steps (A, C types)
2.0%
a transistor, a coil, a diode, and capacitors
Duty ratio: 29% (PFM control)
29 to 100% (PWM control)
Current is set by an external resistor RSENSE.
Time is set by a capacitor CSS and a resistor RSS.
*1. Refer to “Product Name Structure” for details.
Applications
Power supplies for PDAs, electric organizers, and portable devices.
Power supplies for audio equipment such as portable CD players and headphone stereos.
Main or sub Power supplies for notebook computers and peripheral equipment.
Package
8-Pin MSOP
1



S-8541
STEP-DOWN, 600 kHz PWM CONTROL or PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
S-8540/8541 Series
Rev.4.0_02
Block Diagrams
1. A, C types (fixed output voltage)
Pch Power
MOS FET
VIN
L
VIN
Power for IC
Triangular wave
oscillation circuit
EXT
PWM comparator
SENSE
Phase
compensation
circuit
SD
CIN
Error amplifier
PWM or PWM / PFM
switching control
circuit
Shutdown soft start
circuit
VREF1.0 V
Voltage/current
reference
RSENSE
125 mV
VOUT
COUT
VSS
ON/OFF
RSS
CSS
VON/OFF
Figure 1
CVREF
CVL
2. B, D types (feed back)
Pch Power
MOS FET
VIN
L
VIN
Power for IC
Triangular wave
oscillation circuit
EXT
PWM comparator
SENSE
Phase
compensation
circuit
SD
CIN
Error amplifier
PWM or PWM / PFM
switching control
circuit
Shutdown soft start
circuit
VREF1.0 V
Voltage/current
reference
RSENSE
125 mV
VOUT
CFB
FB
VSS
VOUT
RA
COUT
RB
ON/OFF
RSS
CSS
VON/OFF
Figure 2
CVREF
CVL
2





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