S-8340A25AFT-T2-X Datasheet, PDF (1/55 Pages) Seiko Instruments Inc – SWITCHABLE SWITCHING REGULATOR CONTROLLER

S-8340/8341 Series
STEP-UP, 600 kHz, PWM CONTROL OR PWM/PFM
www.sii-ic.com
SWITCHABLE SWITCHING REGULATOR CONTROLLER
© SII Semiconductor Corporation, 1999-2010
Rev.4.0_01
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 (VFB) 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 VDD = 0.9 V
• Built-in current limit circuit: Can be set with an external resistor (RSENSE)
• Soft-start function set by an external capacitor (CSS)
• Shutdown function
• Lead-free, Sn 100%, halogen-free^*1
*1. Refer to “ Product Name Structure” for details.
 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
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