Se Application; Package Ground Connection; Output Power; Reference Design - Philips TDA8928J Datasheet

Philips Semiconductors
Power stage 2 x 10 or 1 x 20 W class-D
audio amplifier
15.1

SE application

For a SE application the application diagram as shown in Fig.5 can be used.
15.2

Package ground connection

The heatsink of the TDA8928J is connected internally to V
15.3

Output power

The output power in SE self oscillating class-D applications can be estimated using the formula
R
L
------------------------------------------------
R + R
L ds(on)
P
= ----------------------------------------------------------------------
o(1%)
2 R
The maximum current
Where:
R = load impedance
L
R = series resistance of filter coil
s
P = output power just at clipping.
o(1%)
The output power at THD = 10 %: P
15.4

Reference design

The reference design for a self oscillating class-D system for the TDA8928J is shown in Fig.5. The Printed-Circuit Board
(PCB) layout is shown in Figs 6, 7 and 8. The bill of materials is given in Section 15.4.2.
2004 May 05
2
V
P
+ R
s
L
V
P
I =
-------------------------------------------
O(max)
R + R +
L ds(on)
= 1.25
o(10%)
.
SS
should not exceed 2 A.
R
s
P .
o(1%)
12
Preliminary specification
TDA8928J