Se Application; Package Ground Connection; Output Power; Reference Design - Philips TDA8925 Datasheet

Philips Semiconductors
Power stage 2 x 15 to 25 W class-D
audio amplifier
15.1

SE application

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

Package ground connection

The heatsink of the TDA8925 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 TDA8925 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 15.5.1.
2004 May 06
2
×
V
P
+ R
s
L
V
P
I =
-------------------------------------------
O(max)
R + R +
L ds(on)
= 1.25 × P
o(10%)
.
SS
should not exceed 3 A.
R
s
.
o(1%)
12
Product specification
TDA8925