PIN FUNCTIONS (continued)

N

°

Name

Function

14

DRIVER EMITT ER

OUTPUT

Current Driver for the External Darlington. To ensure stability and precision

Ω in

order not to change the open loop gain of the system.

situations.

Ω depending on the

external darlington type.

15

OVERVOLTAGE LIMIT

The darlington is protected against overvoltage by means of an internal

zener available at this pin and connected to pin 14. The internal divider



22.5



+ 22.5

16

DRIVER COLLECTOR

INPUT

The collector current of the internal driver which drives the external

the maximum current supplied to the base of the external darlington.

Symbol

Parameter

Test Conditions

Min.

Typ.

Max.

Unit

Min Op. Voltage

3.5

V

Supply Current

5

7

18

25

13

mA

mA

Voltage Supply

28

V

Supply Clamping Zener Voltage

6.8

7.5

8.2

V

Input Voltage

Low Status

High Status

2.5

0.6

V

V

Input Current

– 400

– 50

µA

Darlington Driver Sat. Current

0.5

0.9

V

V

Current Limit. Sensing Voltage

260

320

370

mV

T = 10 to 33ms

– 11.0

– 9.3

– 7.8

µA

CW Charge Current

T = 10 to 33ms

0.5

0.7

1.0

µA

VS = 5.3 to 16V

T = 10 to 33ms

See Note 1

7.8

22.0

Percentage of Output Current

Determining the Slow Recovery

Control Start (fig. 2), note 1

90

94

98.5

%

Duration of Altered Small Contr.

Ratio after SRC Function Start

(fig. 2)

µF

Ω

0.8

s

External Darlington over V Prot.

Zener Voltage

19

18

22.5

21.5

26

25

V

V

Permanent Conduction Time

µF

Ω

0.4

1.1

1.8

s

L497

4/11