MD3203
Filterless 3W Class-D Stereo Audio Amplifier
device. Therefore, it’s recommened to use either
4
Application Notes
1. When then MD3203 works with LC filters, it should be NI-MH(Nickel Metal Hydride)rechargeable batteries or 3 dry
connected with the speaker before it’s powered on,otherwise it or alkaline batteries.
will be damaged easily.
4. One should not make the input signal too large. Large signal
2. When the MD3203 works without LC filters, it’s better to can cause the clipping of output signal when increasing the
add a ferrite chip bead at the outgoing line of speaker for volume. This will damage the device because of big gain of the
suppressing the possible electromagnetic interference.
MD3203
3. The recommended operating voltage is 5.5V. When the 5. When testing the MD3203 without LC filters by using
MD3203 is powered with 4 battery cells, it should be noted resistor instead of speaker as the output load, the test results,
that the voltage of 4 new dry or alkaline batteries is over 6.0V, e.g. THD or efficiency, will be worse than those of using
higher than its operation voltage, which will
speaker as load.
Test Setup for Performance Testing
Notes
1. TheAPAUX-0025lowpassfilterisnecessary 2. Two 22µH inductors are used in series with
for class-D amplifier measurement with AP loadresistortoemulatethesmallspeakerfor
analyzer.
efficiency measurement.
Application Information
Maximum Gain
As shown in block diagram(page 2),the MD3203 has two
internal amplifier stages.The first stage’s gain is
externally configurable,while the second stage’s is
internally fixed. The closed-loop gain of the first
input to amplifier 2, thus the two amplifiers produce
signals identical in magnitude,but different in
phase by 180º.Consequentl,the differential gain for
the
VD=20*log[2*(R
IC
is
stage is set by selecting the ratio of R
f
to R
i
while
A
f
/R
i
)] The MD3203 sets maximum R
f
=142k
电话:0755-82709111 827091112 827091113
传真:0755-82709114
地址:深圳市福田区中航路鼎诚国际大厦南座2805 室
网址:Http://www.YR-IC.com
LUNSURE [ Lunsure Electronic ]
