S-8340/8341 Series
www.sii-ic.com
© Seiko Instruments Inc., 1999-2010
STEP-UP, 600 kHz, PWM CONTROL OR PWM/PFM
SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.4.0
_00
The S-8340/8341 Series is a CMOS step-up switching regulator controller which mainly consists of a reference voltage
source, oscillation circuit, error amplifier, phase compensation circuit, PWM control circuit (S-8340 Series), and PWM/PFM
switching control circuit (S-8341 Series).
Since the oscillation frequency is a high 300 kHz or 600 kHz, with the addition of a small external part, the S-8340/8341
Series functions as a highly efficient step-up switching regulator with a high output current. The speed of the output stage is
enhanced so that the N-channel power MOS with a low on-resistance can be switched quickly.
The S-8340 Series realizes low ripple, high efficiency, and excellent transient characteristics thanks to a PMW control circuit
capable of varying the duty ratio linearly from 0 to 82%, optimized error amplifier, and phase compensation circuit.
The S-8341 Series contains a PWM/PFM switching control circuit so that it operates using PWM control with a duty ratio of
27% or higher and using PFM control with a duty ratio of lower than 27% to ensure high efficiency in all load ranges.
These S-8340/8341 Series serve as ideal main power supply units for portable devices when coupled with the 8-Pin TSSOP
package and high oscillation frequencies.
Features
•
•
•
•
•
•
Oscillation frequency :
600 kHz (A and B types), 300 kHz (C and D types).
Output voltage :
Selectable in 0.1 V steps between 2.5 to 6.0 V (output voltage fixed output type)
Output voltage accuracy :
±2.0%
Output voltage external setting (FB) type available. FB terminal voltage (V
FB
) 1.0 V
External parts :
Coil, diode, capacitors (3), transistor, and resistor only
Duty ratio :
0 to 82% (typ.) PWM control (S-8340 Series)
27 to 82% (typ.) PWM/PFM switching control (S-8341 Series A and B types)
21 to 82% (typ.) PWM/PFM switching control (S-8341 Series C and D types)
Low-voltage operation:
Oscillation guaranteed to start when V
DD
=
0.9 V
Built-in current limit circuit: Can be set with an external resistor (R
SENSE
)
Soft-start function set by an external capacitor (C
SS
)
Shutdown function
Lead-free, Sn 100%, halogen-free
*1
Product Name Structure”
for details.
•
•
•
•
•
*1.
Refer to “
Applications
•
•
•
•
Power supplies for portable equipments such as PDAs, electronic notebooks, and cellular phones
Power supplies for audio equipments such as portable CD players, portable MD players, and headphone stereos
Main or local power supplies for notebook PCs and peripherals
Constant voltage power supplies for cameras, VCRs, and communication devices
Package
•
8-Pin TSSOP
Seiko Instruments Inc.
1
STEP-UP, 600 kHz, PWM CONTROL OR PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.4.0
_00
S-8340/8341 Series
Product Name Structure
The control method, product type, and output voltage values for the S-8340/8341 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-834
x
x
xx
A FT – T2 – 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
Package name (abbreviation)
FT : 8-Pin TSSOP
Output voltage
25 to 60
(E.g., when the output voltage is 2.5 V, it is expressed as 25.)
Product type
A : Output voltage fixed output type, f
OSC
= 600 kHz
B : Output voltage external setting type, f
OSC
= 600 kHz
C : Output voltage fixed output type, f
OSC
= 300 kHz
D : Output voltage external setting type, f
OSC
= 300 kHz
Control method
0 : PWM control
1 : PWM/PFM switching control
*1
*1.
Refer to the tape drawing.
2.
Package
Package Name
8-Pin TSSOP
Environmental code = G
Environmental code = U
Drawing Code
Tape
FT008-E-C-SD
FT008-E-C-SD
Package
FT008-A-P-SD
FT008-A-P-SD
Reel
FT008-E-R-SD
FT008-E-R-S1
Seiko Instruments Inc.
3
STEP-UP, 600 kHz, PWM CONTROL OR PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.4.0
_00
S-8340/8341 Series
3. Product Name List
(1) Output Voltage Fixed Output Type
Table 1
Output Voltage
(V)
S-8340 Series
A Type
f
OSC
= 600 kHz
PWM Control
S-8341 Series
A Type
f
OSC
= 600 kHz
PWM/PFM Switching
Control
S-8340 Series
C Type
f
OSC
= 300 kHz
PWM Control
S-8341 Series
C Type
f
OSC
= 300 kHz
PWM/PFM Switching
Control
2.5 V
S-8340A25AFT-T2-x
S-8341A25AFT-T2-x
S-8340C25AFT-T2-x
S-8341C25AFT-T2-x
3.0 V
S-8340A30AFT-T2-x
S-8341A30AFT-T2-x
S-8340C30AFT-T2-x
S-8341C30AFT-T2-x
3.3 V
S-8340A33AFT-T2-x
S-8341A33AFT-T2-x
S-8340C33AFT-T2-x
S-8341C33AFT-T2-x
3.4 V
S-8340A34AFT-T2-x
−
−
−
3.5 V
S-8340A35AFT-T2-x
−
−
−
5.0 V
S-8340A50AFT-T2-x
S-8341A50AFT-T2-x
S-8340C50AFT-T2-x
S-8341C50AFT-T2-x
5.1 V
S-8340A51AFT-T2-x
−
−
S-8341C51AFT-T2-x
5.6 V
S-8340A56AFT-T2-x
−
−
−
6.0 V
S-8340A60AFT-T2-x
−
S-8340C60AFT-T2-x
−
Remark 1.
Contact the SII marketing department for products with an output voltage other than those specified above.
2.
x: G or U
3.
Please select products of environmental code = U for Sn 100%, halogen-free products.
(2) Output Voltage External Setting Type
Table 2
S-8340 Series
B Type
f
OSC
= 600 kHz
PWM Control
S-8341 Series
B Type
f
OSC
= 600 kHz
PWM/PFM Switching
Control
S-8340 Series
D Type
f
OSC
= 300 kHz
PWM Control
S-8341 Series
D Type
f
OSC
= 300 kHz
PWM/PFM Switching
Control
Output Voltage
(V)
External setting S-8340B00AFT-T2-x
S-8341B00AFT-T2-x
S-8340D00AFT-T2-x
S-8341D00AFT-T2-x
Remark 1.
x: G or U
2.
Please select products of environmental code = U for Sn 100%, halogen-free products.
4
Seiko Instruments Inc.
STEP-UP, 600 kHz, PWM CONTROL OR PWM/PFM SWITCHABLE SWITCHING REGULATOR CONTROLLER
Rev.4.0
_00
S-8340/8341 Series
Pin Configurations
Table 3
8-Pin TSSOP
Top view
1
2
3
4
8
7
6
5
Pin No.
1
2
3
4
5
Symbol
VSS
CVREF
CSS
ON/OFF
VDD
VOUT
(FB)
EXT
SENSE
Pin Description
GND pin
Reference voltage source pass capacitor connection
pin
Soft-start capacitor connection pin
Shutdown pin
“H” : Normal operation (step-up operating)
“L” : Entire circuit stopped (step-up stopped)
IC power supply pin
Output voltage fixed output type :
Output voltage monitoring pin
[Output voltage external setting type :
Feedback pin]
External transistor connection pin
Current limit detection pin
Figure 3
6
7
8
Seiko Instruments Inc.
5
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