5

Device characteristics

5.1

Thermal protection

Any overtemperature event forces the line driver to self-disable the power amplifiers, thus preventing the STLD1

from damage. The thermal feedback is provided on THERM pin by a current that is N times the IBIAS_IN input

current, according to the relationship described in the following table.

I(THERMAL)

Junction temperature level

0 x I(IBIAS_IN)

Tj < T1

1 x I(IBIAS_IN)

T1 < Tj < T2

2 x I(IBIAS_IN)

T2 < Tj < T3

3 x I(IBIAS_IN)

T3 < Tj < T4

4 x I(IBIAS_IN)

Tj > T4

5.2

Current feedback

Current sense feedback is provided by CSF_OUT current output, proportional to the LD output current. The

CSF_OUT current is converted into voltage by a resistor and compared with the current limit threshold set at

system level.

5.3

Power management

The STLD1 operates from a single 8-18 V external supply. It directly supplies the power amplifiers and the internal

5 V linear regulator for the analog and control circuitry. The block diagram for the power management is shown in

the figure below.

5 V

Linear

Reg.

PVCC

VCC

AVDD_5V

AGND

PGND

PA1_OUT

Power

amplifiers

PA2_OUT

+

8 V to

18 V

Internal

circuitry

STLD1

Device characteristics

DS12339 - Rev 2

page 10/13