S-8533 Series
www.sii-ic.com
© Seiko Instruments Inc., 2002-2010
STEP-DOWN, SYNCHRONOUS PWM CONTROL
SWITCHING REGULATOR CONTROLLER
Rev.3.0
_00
The S-8533 Series is a synchronous PWM control CMOS step-down switching regulator controller that includes a reference
voltage source, synchronous circuit, oscillation circuit, error amplifier, phase compensation circuit, and PWM controller.
An efficient step-down switching regulator can be realized simply by adding external P-channel and N-channel power MOS
FETs, one coil, and three capacitors.
Since the oscillation frequency is a high 300 kHz, the S-8533 can be used to configure a high efficiency step-down switching
regulator capable of driving high output current using small external parts and a 3 to 10% increase in efficiency is obtained
compared to conventional step-down switching regulators.
The 8-Pin TSSOP package and high oscillation frequency make the S-8533 ideal as the main power supply for portable
devices.
Features
•
Synchronous rectification system realizing high efficiency (typ. 94%)
•
Use at maximum duty ratio = 100% and use of a battery up to maximum life is possible by using P-channel and N-
channel power MOS FETs externally.
•
Oscillation frequency :
300 kHz typ.
•
Input voltage :
2.7 to 16.0 V
•
Output voltage :
1.25 V
1.3 to 6.0 V, selectable in 0.1 V steps
•
Output voltage accuracy :
±2.0%
•
Soft-start function set by an external capacitor (C
SS
)
•
Shutdown function
•
Lead-free, Sn 100%, halogen-free
*1
*1.
Refer to “
Product Name Structure”
for details.
Applications
•
•
•
•
Constant voltage power supply for hard disks and DVD drivers
Power supplies for portable devices, such as digital cameras, PDAs, electronic organizers, and cellular phones
Main or sub power supply for notebook PCs and peripherals
Constant voltage power supply for cameras, video equipment, and communication equipment
Package
•
8-Pin TSSOP
Seiko Instruments Inc.
1
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
Rev.3.0
_00
S-8533 Series
Product Name Structure
The output voltage for the S-8533 Series can be selected depending on usage. Refer to “1.
Product Name”
for the
definition of the product name, “2.
Package”
regarding the package drawings and “3.
Product Name List”
for the full
product names.
1. Product Name
S-8533A xx
x
FT
–
TB
–
x
Environmental code
U: Lead-free (Sn 100%), halogen-free
G: Lead-free (for details, please contact our sales office)
IC direction in tape specifications
*1
Package name (abbreviation)
FT : 8-Pin TSSOP
Output voltage
A : 1.3 to 6.0 V
5 : 1.25 V
Output voltage
13 to 60
(E.g., when the output voltage is 1.5 V, it is expressed as 15.)
The product whose output voltage is 1.25 V expresses 12.
*1.
Refer to the tape specifications.
2. Package
Drawing Code
Tape
FT008-E-C-SD
FT008-E-C-SD
Package Name
8-Pin TSSOP
Environmental code = G
Environmental code = U
Package
FT008-A-P-SD
FT008-A-P-SD
Reel
FT008-E-R-SD
FT008-E-R-S1
Seiko Instruments Inc.
3
STEP-DOWN, SYNCHRONOUS PWM CONTROL SWITCHING REGULATOR CONTROLLER
Rev.3.0
_00
S-8533 Series
Pin Configurations
Table 1
8-Pin TSSOP
Top view
1
2
3
4
8
7
6
5
Figure 2
No connection
Output voltage pin
Shutdown pin
H : Normal operation (step-down operation)
3
ON/
OFF
L : Step-down operation stopped (all circuits
deactivated)
4
CSS
Soft start capacitor connection pin
5
VSS
GND pin
6
NDRV
External N-channel connection pin
7
PDRV
External P-channel connection pin
8
VIN
IC power supply pin
*1.
The NC pin is electrically open. Connection of this pin to VIN or VSS is
allowed.
Pin No.
1
2
Symbol
NC
*1
VOUT
Pin Description
Seiko Instruments Inc.
5
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