TFA9842AJ Philips, TFA9842AJ Datasheet - Page 12

• Manufacturer Part Number: TFA9842AJ
• Description: 7.5W Stereo Power Amplifier
• Manufacturer: Philips

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Philips Semiconductors
TFA9842AJ_1
Preliminary specification
13.2.2 Power supply decoupling
13.3 Thermal behavior and heatsink calculation
Proper supply bypassing is critical for low-noise performance and high supply voltage
ripple rejection. The respective capacitor location should be as close as possible to the
device and grounded to the power ground. Proper power supply decoupling also prevents
oscillations.
For suppressing higher frequency transients (spikes) on the supply line a capacitor with
low ESR, typical 100 nF, has to be placed as close as possible to the device. For
suppressing lower frequency noise and ripple signals, a large electrolytic capacitor, e.g.
1000 F or greater, must be placed close to the device.
The bypass capacitor connected to pin SVR reduces the noise and ripple on the mid rail
voltage. For good THD and noise performance a low ESR capacitor is recommended.
The measured maximum thermal resistance of the IC package, R
A calculation for the heatsink can be made, with the following parameters:
R
heatsink. This can be calculated using the maximum temperature increase divided by the
power dissipation:
Fig 15. Printed-circuit board layout (single-sided); components view
th(tot)
T
V
T
amb(max)
j(max)
CC
= 17 V and R
is the total thermal resistance between the junction and the ambient including the
= 150 C (specification)
= 60 C (example)
L
CIV
= 4
22
F
CIV
Rev. 01 — 28 April 2006
(SE)
SGND
220
nF
AUDIO POWER CS NIJMEGEN
IN2
7.5 W stereo power amplifier with volume control
P
F
/
3
220
nF
0
TVA
0
IN1
2
100 nF
n .
J a
7
2
1000 F
+V
P
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
k
10
150 F
MUTE
SB ON
10 k
TFA9842AJ
th(j-mb)
MODE
001aaa426
, is 2.0 K/W.
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