May 22, 2006

Step-Down Switching Regulator IC
SI-8000HFE Series
With 5.5 A output current. Step-Down circuit configurable only by four external components.

Sanken Electric has developed the SI-8000HFE Series step-down switching regulator ICs (two output voltage types: variable, 0.8 to 15 V; fixed, 5 V) capable of supplying 5.5A output current though in a compact (5-pin TO220F) package, and has started the sample shipment. Mass production will be launched on June 1 starting with 150k pcs/month, then ramping up to 500k pcs/month by the end of CY06. (Sample price: 600 Yen)
Sanken Electric is also planning to develop the surface mount type SI-8008HD Series (5-pin TO263 package).

1. Development Background and Product Overview
  In recent years, power supply voltages of ICs such as microcomputers and digital signal processors (DSPs) used in electronic equipment have been lowered in accordance with the power saving trend in equipment, and have become diverse as well. Moreover, as regulator ICs supplying the power to those ICs, switching regulator ICs has increasingly been demanded to improve the efficiency.

Conventionally, most of the currents required by those devices were 3A or lower, so most of the regulator ICs were of 3A-or-lower outputs. As digital ICs, however, are increasingly used in devices, market demands for regulator ICs exceeding 3 A are also increasing.

Sanken Electric has thus developed the SI-8000HFE Series step-down switching regulator ICs, built in a compact package (5-pin TO220F) and capable of supplying an output current of 5.5 A. The SI-8000HFE Series incorporates a phase correction circuit internally for stabilizing output voltage so that the six external components normally needed in the regulator circuit can be reduced to four.

The oscillation frequency has been increased to 150 kHz, allowing the external smoothing choke coil to be downsized (Approximately 50% footprint in comparison with 70 kHz device).

The variable output voltage type allows output voltage to be varied from 0.8 V, so the voltage can be easily set to meet the low voltage requirements of recent digital ICs.

< Main Applications >
On-board local power supply for Audio-Video (AV) equipment, large Office-Automation (OA) equipment, amusement equipment and others

2. Features
Output current: 5.5 A
High efficiency: 83% (typ. at Vo = 5 V)
Operating frequency: 150 kHz, allowing a smaller smoothing choke coil
Protection functions: Drooping-type overcurrent and thermal protection functions
Auxiliary function: Built-in output on/off control function (Soft start also possible.)
Circuit current when output is off: 400 µA max. (typ. 200µA), enabling low power consumption at standby
External components for circuit configuration: Four components of I/O smoothing capacitors, flywheel diode, and smoothing choke coil.
3. Features
SI-8000HFE SI-8000HD
4. Specification Overview
Parameter Ratings Unit
SI-8008HFE SI-8050HFE
Input voltage 43 V
Power dissipation 25 W
Output current 5.5 A
Reference voltage 0.8 - V
Output voltage - 5.0 V
Efficiency (typ.) 83 %
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