TDA8944AJ Datasheet, PDF (16/20 Pages) NXP Semiconductors – 2 x 7 W BTL audio amplifier with DC gain control

Philips Semiconductors
TDA8944AJ
2 x 7 W BTL audio amplifier with DC gain control
At V_CC = 12 V and R_L = 8 Ω the measured worst-case sine-wave dissipation is 8 W;
see Figure 12. For T_j(max) = 150 °C the temperature rise - caused by the power
dissipation - is: 150 − 50 = 100 °C.
P × R_th(tot) = 100 °C
R_th(tot) = 100/8 = 12.5 K/W
R_th(h-a) = R_th(tot) − R_th(j-mb) = 12.5 − 4.5 = 8.0 K/W.
The calculation above is for an application at worst-case (stereo) sine-wave output
signals. In practice music signals will be applied, which decreases the maximum
power dissipation to approximately half of the sine-wave power dissipation (see
Section 8.2.2). This allows for the use of a smaller heatsink:
P × R_th(tot) = 100 °C
R_th(tot) = 100/(0.5 × 8) = 25 K/W
R_th(h-a) = R_th(tot) − R_th(j-mb) = 25 − 4.5 = 20.5 K/W.
To increase the lifetime of the IC, T_j(max) should be reduced to 125 °C. This requires a
heatsink of approximately 14 K/W for music signals.
15. Test information
15.1 Quality information
The “General Quality Specification for Integrated Circuits, SNW-FQ-611D” is
applicable (ordering code 9397 750 05459).
15.1.1 Test conditions
T_amb = 25 °C; V_CC = 12 V; f = 1 kHz; R_L = 8 Ω; audio pass band 22 Hz to 22 kHz;
unless otherwise specified.
Remark: In the graphs as function of frequency no bandpass filter was applied;
see Figure 9 and 13.
9397 750 09433
Product data
Rev. 01 — 01 March 2002
© Koninklijke Philips Electronics N.V. 2002. All rights reserved.
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