ST L4918 User Manual

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VOLTAGE REGULATORSPLUS FILTER

.FIXEDOUTPUT VOLTAGE8.5V

.250mAOUTPUT CURRENT

.HIGH RIPPLEREJECTION

.HIGH LOADREGULATION

.HIGH LINE REGULATION

.SHORTCIRCUIT PROTECTION

.THERMALSHUTDOWN WITHHYSTERESIS

.DUMPPROTECTION

DESCRIP TIO N

TheL4918combinesbothafilterandavoltageregu­latorinordertoprovidea high ripplerejectionovera
widerinput voltagerange.

A supervisorlow-passloop of theelement prevents
the outputtransistorfrom saturationat low inputvol
tages.

The non linear behaviourof this control circuitry al­lowsa fastsettingofthe filter.

L4918

PRELI MINA RY DATA

PENTAWATT

ORDERING NUMBER : L4918

BLOCK DIAGRAM

October1988

1/6

L4918

PIN CONNECTIO N (top view)

Figure 1 : Applicationand TestCircuit.

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

Peak Input Voltage (300 ms) 40 V

V

i

DC Input Voltage 28 V

V

i

Output Current Internally Limited

I

O

Power Dissipation Internally Limited

P

tot

T

stg,Tj

Storage and Junction Temperature – 40 to 150 °C

THERMAL DATA

Symbol Parameter Value Unit

Thermal Resistance Junction-case Max 4 °C/W

2/6

R

th j-case