TFA9843J 查看數據表（PDF） - NXP Semiconductors.
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TFA9843J Datasheet PDF : 21 Pages
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Philips Semiconductors
TFA9843J
2-channel audio amplifier (2 x SE or 1 x BTL)
• No expensive DC-blocking capacitor
• Good low frequency performance.
8.2.1 Output power measurement
The output power as a function of the supply voltage is measured on the output pins
at THD = 10 %; see Figure 11. The maximum output power is limited by the supply
voltage of 26 V and the maximum available output current is 4 A repetitive peak
current. A minimum load (SE) of 3 Ω is required for supply voltages > 22 V; see
Figure 5. A minimum load (BTL) of 6 Ω is required for supply voltages > 22 V; see
Figure 6.
8.2.2 Headroom
Typical CD music requires at least 12 dB (factor 15.85) dynamic headroom,
compared to the average power output, for transferring the loudest parts without
distortion. At VCC = 18 V and Po = 5 W (SE with RL = 4 Ω) or Po = 10 W (BTL with
RL = 8 Ω) at THD = 0.2 % (see Figure 7), the Average Listening Level (ALL) music
power without any distortion yields:
Po(ALL, SE) = 5---1--×-5---.-18---05---3- = 315 mW
(4)
Po(ALL, BTL) = 1----01---5-×--.--8-1--5-0---3- = 630 mW
(5)
The power dissipation can be derived from Figure 13 (SE) or Figure 14 (BTL) for 0 dB
respectively 12 dB headroom (see Table 4).
Table 4: Power rating as function of headroom
Headroom
Power output (THD = 0.2 %)
SE
BTL
0 dB
12 dB
Po = 5 W
Po = 10 W
Po(ALL) = 315 mW Po(ALL) = 630 mW
Power dissipation (PD);
both channels driven
8.4 W
4.2 W
For the average listening level a power dissipation of 4.2 W can be used for a
heatsink calculation.
8.3 Mode selection
The TFA9843J has three functional modes, which can be selected by applying the
proper DC voltage to pin MODE (see Table 5 and Figure 3).
Table 5: Mode selection
VMODE
0 to 0.8 V
4.5 V to (VCC − 3.5 V)
(VCC − 2.0 V) to VCC
Amplifiers 1 and 2
standby
mute
on
9397 750 12587
Preliminary data
Rev. 02 — 19 January 2004
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
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