Power Management ICs

Synchronous PWM Control Step-Down Switching Regulator (DC-DC Converter ICs) S-8533 Series

The S-8533 series is a synchronous PWM control CMOS step-down switching regulator (DC-DC Converter ICs) controller that includes a reference voltage source, synchronous circuit, an oscillation circuit, an error amplifier, a phase compensation circuit, and a PWM controller.
An efficient step-down switching regulator (DC-DC Converter ICs) can be realized simply by adding external Pch and Nch power MOSFETs, 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 (DC-DC Converter ICs) capable of driving high output current using small external components and a 3 to 10% in-crease in efficiency is obtained compared to conventional step-down switching regulators(DC-DC Converter ICs).
The 8-Pin TSSOP and high oscillation frequency make the S-8533 ideal as the main power supply for portable devices.


Synchronous rectification system realizing high efficiency (typ. 94%)
External components
Use at maximum duty = 100% and use of a battery up to maximum life is possible by using Pch and Nch MOS transistors externally.
Oscillation frequency
300 kHz
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
Soft start
Can be set by an external capacitance CSS
Shutdown function
Lead-free products


  • 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 computers and peripheral equipment
  • Constant voltage power supply for cameras, video equipment, and communication devices

Standard Circuit

Standard Circuit