TFA9842AJ 查看數據表（PDF） - NXP Semiconductors.

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TFA9842AJ

7.5 W stereo power amplifier with volume control

NXP Semiconductors. 

Philips Semiconductors

TFA9842AJ

7.5 W stereo power amplifier with volume control

8.5 Built-in protection circuits

The TFA9842AJ contains two types of temperature sensors; one measures the local

temperatures of the power stages and one measures the global chip temperature. At a

local temperature of the power stage of approximately 185 °C or a global temperature of

approximately 150 °C this detection circuit switches off the power stages for 2 ms. When

the outputs are switched off the voltage is measured on the outputs. In the event of a

short-circuit to ground or to VCC the device will remain in Protection mode. In all other

cases the power stages switch-on automatically and the detection will take place again;

however a too high temperature will switch-off the power stages immediately. This can

result in repetitive switching during too high junction temperature. This protects the

TFA9842AJ against short-circuits to ground, to the supply voltage, across the load and too

high chip temperatures.

The protection will only be activated when necessary, so even during a short-circuit

condition, a certain amount of (pulsed) current will still flow through the short-circuit (as

much as the power stage can handle without exceeding the critical temperature level).

9. Limiting values

Table 6. Limiting values

In accordance with the Absolute Maximum Rating System (IEC 60134).

Symbol Parameter

Conditions

Min

VCC

supply voltage

operating

−0.3

VI

input voltage

−0.3

IORM

repetitive peak output

-

current

Tstg

storage temperature

non-operating

−55

Tamb

ambient temperature

operating

−40

Ptot

total power dissipation

-

VCC(scp)

short-circuit protection

-

supply voltage

Max

Unit

+28

V

VCC + 0.3 V

3

A

+150

°C

+85

°C

35

W

26

V

10. Thermal characteristics

Table 7. Thermal characteristics

Symbol Parameter

Conditions

Rth(j-a)

Rth(j-c)

thermal resistance from junction to ambient in free air

thermal resistance from junction to case both channels driven

Typ Unit

40 K/W

2.0 K/W

TFA9842AJ_1

Preliminary specification

Rev. 01 — 28 April 2006

© Koninklijke Philips Electronics N.V. 2006. All rights reserved.

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