APA2069
Typical Characteristics (Cont.)
Power Dissipation vs. Output Power
200
RL=8W
180
160
140
120
RL=16W
100
80
RL=32W
60
40
VDD=5V
THD<1%
20
SE
0
0
50
100
150
200
250
Output Power(W)
Application Descriptions
BTL Operation
The power amplifier’s OP1 gain is setting by internal
unity-gain and input audio signal is come from internal
volumecontrolamplifier,whilethesecondamplifierOP2
isinternallyfixedinaunity-gain,invertingconfiguration.
Figure 1 shows that the output of OP1 is connected
to the input to OP2, which results in the output signals
of with both amplifiers with identical in magnitude, but
out of phase 180°. Consequently, the differential gain
for each channel is 2 x (Gain of SE mode).
The APA2069 output stage (power amplifier) has two
pairs of operational amplifiers internally, allowed for
different amplifier configurations.
OUT+
Volume Control
amplifier output
signal
OP1
Bydrivingthe loaddifferentiallythroughoutputsOUT+
andOUT-,anamplifierconfigurationcommonlyreferred
to asbridged mode isestablished. BTLmodeoperation
isdifferent from the classical single-ended SE amplifier
configuration where one side of its load is connected
RL
OUT-
OP2
Vbias
Circuit
to ground.
Figure 1: APA2069 internal configuration
(each channel)
A BTL amplifier design has a few distinct advantages
Copyright ã ANPEC Electronics Corp.
17
www.anpec.com.tw
Rev. A.1 - Aug., 2005
ANPEC [ ANPEC ELECTRONICS COROPRATION ]
