AS1701_1 AMSCO [austriamicrosystems AG], AS1701_1 Datasheet - Page 11

• Manufacturer Part Number: AS1701_1
• Description: 1.6W Audio Power Amplifiers
• Manufacturer: AMSCO [austriamicrosystems AG]

AS1701, AS1706
Data Sheet
9 Application Information
BTL Amplifier
The AS1701/AS1706 are designed to drive loads differentially in a bridge-tied load (BTL) configuration.
Figure 30. Bridge-Tied Load Configuration
Driving the load differentially doubles the output voltage (illustrated in
under similar conditions. Thus, the differential gain of the device is twice the closed-loop gain of the input amplifier. The
effective gain is calculated by:
Substituting 2 x V
age.
Since the differential outputs are biased at mid-supply, there is no net DC voltage across the load, eliminating the need
for the large, expensive, performance degrading DC-blocking capacitors required by single-ended amplifiers.
Power Dissipation and Heat Sinking
Normally, the devices dissipate a significant amount of power. The maximum power dissipation is given in
Continuous Power Dissipation, or it can be calculated by:
where T
tor in °C/W.
The increased power delivered by a BTL configuration normally results in increased internal power dissipation versus
a single-ended configuration. The maximum internal power dissipation for a given V
www.austriamicrosystems.com
J(MAX)
- A p p l i c a t i o n I n f o r m a t i o n
is +150°C, T
OUT(P-P)
into (EQ 3) and (EQ 4) yields four times the output power due to doubling of the output volt-
AMB
(see
Table
P
P
2) is the ambient temperature, and Θ
DISSPKF(MAX)
DISSPKF(MAX)
V
P
A
RMS
OUT
VD
+1
-1
Revision 1.52
= 2 x
=
=
=
=
V
V
OUT(P-P)
RMS
R
R
2 2
R
T
2V
π
L
IN
J(MAX)
F
2
DD
2
R
Θ
L
JA
2
-T
Figure
A
30) compared to a single-ended amplifier
JA
is the reciprocal of the derating fac-
DD
2 x V
V
V
OUT(P-P)
OUT(P-P)
and load is calculated by:
OUT(P-P)
Table 2
(EQ 2)
(EQ 3)
(EQ 4)
(EQ 5)
(EQ 6)
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