EXTERNAL TRANSISTOR TYPE CMOS VOLTAGE REGULATOR

S-816 Series

12

Seiko Instruments Inc.



Precautions

• The overcurrent protection function of this IC detects and limits the sink current at the EXT pin inside the

IC. Therefore, it does not work on collector overcurrents which are caused by an EXT-GND short-

circuiting or other phenomenon outside the IC. To protect the external PNP transistor from collector

overcurrents perfectly, it is necessary to provide another external overcurrent protection circuit.

• This IC performs phase compensation by using an internal phase compensator circuit and the ESR of an

output capacitor. Therefore, always place a capacitor of 4.7

μF or more between VOUT and VSS.

A tantalum type capacitor is recommended for this purpose. Moreover, to secure stable operation of the

S-816 Series, it will be necessary to employ a capacitor having an ESR (Equivalent Series Resistance)

covered in a certain optimum range (0.1

Ω to 5 Ω). Whether an ESR is larger or smaller than that

optimum range, this could result in an unstable output, and cause a possibility of oscillations. Select a

capacitor through careful evaluation made according to the actual service conditions.

• Overshoot may occur in the output voltage momentarily if the voltage is rapidly raised at power-on or

when the power supply fluctuates. Sufficiently evaluate the output voltage at power-on with the actual

device.

• Do not apply an electrostatic discharge to this IC that exceeds the performance ratings of the built-in

electrostatic protection circuit.

• Make sure that the power dissipation inside the IC due to the EXT output sink current (especially at a high

temperature) will not surpass the power dissipation of the package.

• SII claims no responsibility for any disputes arising out of or in connection with any infringement by

products including this IC of patents owned by a third party.