DC/DC Step-Down Converter IC

SI-8000TM Series

September 2005

Sanken Electric Co.,Ltd.

I02-001EA-050910

*3

Efficiency is calculated by the following equation.

*4

No.5 terminal is a SS terminal to enable soft start by connecting a capacitor. The output can

be turned on and off by using a SS terminal. The output is stopped by decreasing the SS

to connect NPN transistor or the output of open collector type TTL between No.5 terminal

and GND.

In case that both soft and Vout ON/OFF are used, a protection measure such as limitation of

current is required, as the discharge current of C3 flows across a transistor for ON/OFF

operation, if the capacitance of C3 large. As a pull-up type resistor is provided inside the IC,

no external voltage can be applied. In case of no use of ON/OFF, please keep it open.

（１）

Efficiency

η

(%)=

×

100

Soft start

C3

5

SS

Soft start

C3

SI-8000TFE

SI-8000TFE

SI-8000TFE

5

SS

5

SS

SI-8000TM

SI-8000TM

SI-8000TM

Efficiency

Efficiency

SI-8008TM／TFE　効率特性

Ta=25℃　Vo=5v設定時

55

60

65

70

75

80

85

00.511.5

Iout　A

VIN=

8v,10v,15v,20v,30v,

40v

Vo=5V adjusted：R1=42kΩ R2=08kΩ

Efficincy Curve

SI-8008TM Efficiency Curve

Vo=5V Adjusted：R1=4.2kOhm, R2=0.8kOhm

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