AN2378

L9935 open-load production test

Doc ID 12435 Rev 3

9/13

3

L9935 open-load production test

For testing the open-load functionality, STMicroelectronics™ uses a special go/no-go test

with the parameters defined in Table 1. Devices that pass this test do not generate an open-

load error if the load current—16 µs after going in flyback—remains higher than 90 mA.

Equation 3

An open-load is detected if the magnitude of the flyback voltage, 16 µs after going in flyback,

is less than 60 mV:

Equation 4

Table 1.

resistance)

Parameters

ST screening test

Unit

14

V

1.2

ohm

0.4

ohm

82

ohm

5mH

0.17

A

0.089

A

1.

voltage over the comparator as expressed in Equation 3.

V

V



V

R

DS ON



R

shunt

+

R

-------------------------------------------- *

1

2 *

t

R

L

M

-------

–





exp

–





=

V

=

 60mV

