Power Management ICs

Super-Small Package PFM Control Step-Up Switching Regulator (DC-DC Converter ICs) S-8351/8352 Series

The S-8351/8352 series is a CMOS PFM-control step-up switching regulator (DC-DC Converter ICs) that mainly consists of a reference voltage source, an oscillator, and a comparator. The PFM controller allows the duty ratio to be automatically switched according to the load (light load: 50%, high output current: 75%), enabling products with a low ripple over a wide range, high efficiency, and high output current (product types A, B, and D). Products with a fixed duty ratio of 75% are also available (product type C). With the S-8351 series, a step-up switching regulator (DC-DC Converter ICs) can be configured by using an external coil, capacitor, and diode. The built-in MOS FET is turned off by a protection circuit when the voltage at the CONT pin exceeds the limit to prevent it from being damaged. This feature, along with the mini package and low current consumption, makes the S-8351 series ideal for applications such as the power supply unit of portable equipment.
The S-8352 series, which features an external transistor, is suitable for applications requiring a high output current.

Features

Low voltage operation
Startup at 0.9 V min. (Iout = 1 mA) guaranteed
Low input current
During maximum operation 23.2 µA (Vout = 3.3 V, typ.), During shutdown 0.5 µA (max.)
Duty ratio
50/75%, built-in auto-switching-type PFM controller (product types A, B, D)
75%, built-in fixed-type PFM controller (product type C)
External parts
Coil, capacitor, diode
Output voltage
Settable to between 2.0 to 6.5 V (product types A, B, C) or 1.5 to 6.5 V (product type D) in 0.1 V steps, accuracy of ±2.4%
Shutdown function (product type A)
Vdd / Vout separate type (product type D)
External transistor type available (S-8352 series)
Lead-free products

Applications

  • Power supply for portable equipment such as digital cameras, electronic notebooks, and PDAs
  • Power supply for audio equipment such as portable CD/MD players
  • Constant voltage power supply for cameras, video equipment, and communications equipment
  • Power supply for microcomputers

Standard Circuit

Standard Circuit