TDA8947J/N3,112 データシートの表示（PDF） - NXP Semiconductors.

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TDA8947J/N3,112

4-channel audio amplifier

NXP Semiconductors. 

Philips Semiconductors

TDA8947J

4-channel audio amplifier

8.5 Built-in protection circuits

The TDA8947J contains two types of detection sensors: one measures local temperatures

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

temperature of approximately 185 °C or a global temperature of approximately 150 °C,

this detection circuit switches off the power stages for 2 ms. High-impedance of the

outputs is the result. After this time period the power stages switch on automatically and

the detection will take place again; still a too high temperature switches off the power

stages immediately. This protects the TDA8947J against shorts to ground, to the supply

voltage and across the load, and against 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 be flowing through the short, just 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

no (clipping) signal [1] −0.3

VI

input voltage

−0.3

IORM

repetitive peak output

-

current

Tstg

storage temperature

non-operating

−55

Tamb

ambient temperature

−40

Ptot

total power dissipation

-

VCC(sc)

supply voltage to guarantee

-

short-circuit protection

Max

Unit

+26

V

+28

V

VCC + 0.3 V

4

A

+150

°C

+85

°C

69

W

24

V

[1] The amplifier can deliver output power with non clipping output signals into nominal loads as long as the

ratings of the IC are not exceeded.

10. Thermal characteristics

Table 7: Thermal characteristics

Symbol Parameter

Conditions

Typ

Unit

Rth(j-a) thermal resistance from junction to ambient in free air

40

K/W

Rth(j-c) thermal resistance from junction to case all channels driven 1.3

K/W

9397 750 14938

Product data sheet

Rev. 02 — 16 June 2005

© Koninklijke Philips Electronics N.V. 2005. All rights reserved.

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