TDF8554J NXP Semiconductors, TDF8554J Datasheet - Page 49

• Manufacturer Part Number: TDF8554J
• Description: The TDF8554J is one of a new generation of complementary quad Bridge-Tied Load(BTL) audio power amplifiers with full I²C-bus controlled diagnostics, multiple voltageregulator and two power switches intended for automotive applications
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TDF8554J
Product data sheet
14.2 Beep input circuit
14.3 Regulator output noise
14.4 Regulator stability
Beep input circuit to amplify the beep signal from the microcontroller to all 4 amplifiers with
gain set to 0 dB. Note that this circuit will not affect amplifier performance.
The outputs of regulators 1 to 5 are designed to give very low noise with good stability.
The noise output voltage depends on output capacitor C
output capacitor on the noise figure.
Table 27.
[1]
The regulators are made stable by the external capacitors connected to the regulator
outputs. The stability can be guaranteed with almost any output capacitor if its Equivalent
Series Resistance (ESR) stays below the ESR curve shown in
capacitor is used, its behavior with temperature can cause oscillations at extremely low
temperature. Oscillation problems can be avoided by adding a 47 nF capacitor in parallel
with the electrolytic capacitor. The following example describes how to select the value of
output capacitor.
Regulator
1
2
3
4
5
Fig 33. Application diagram for beep input
Measured in the frequency range 20 Hz to 80 kHz; at I
Regulator noise figures
from microcontroller
All information provided in this document is subject to legal disclaimers.
Noise figure (V)
C
225
750
120
225
320
Rev. 1 — 31 August 2011
o
= 10 F
4 45 W power amplifier with multiple voltage regulator
1.7 kΩ
0.22 μF
[1]
C
195
550
100
195
285
o
100 Ω
O(reg)
= 47 F
= 10 mA.
2.2 μF
o
ACGND
.
Table 27
47 pF
Figure
TDF8554J
shows the affect of the
C
185
530
95
185
270
TDF8554J
o
34. If an electrolytic
aaa-000379
= 100 F
© NXP B.V. 2011. All rights reserved.
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