TDF8555J NXP Semiconductors, TDF8555J Datasheet - Page 50

• Manufacturer Part Number: TDF8555J
• Description: The TDF8555J 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
TDF8555J
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 6 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
6
Fig 32. 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.
Rev. 1 — 15 September 2011
Noise figure (V)
C
225
700
100
235
315
710
o
= 10 F
4 45 W power amplifier with multiple voltage regulator
1.7 kΩ
0.22 μF
[1]
C
180
600
85
205
285
550
o
100 Ω
O(reg)
= 47 F
= 10 mA.
2.2 μF
o
ACGND
.
Table 27
47 pF
Figure
TDF8555J
shows the affect of the
C
145
390
65
175
225
340
TDF8555J
o
33. If an electrolytic
001aan415
= 100 F
© NXP B.V. 2011. All rights reserved.
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