SM6800A Datasheet, PDF (8/12 Pages) Nippon Precision Circuits Inc – Class-D Mono Amplifier for Mobile Telephones

SM6800A
Input Equalizer (IN, EQP, EQN)
An input equalizer network can be connected to pins IN, EQP, and EQN, as shown in the input equivalent cir-
cuit and equalizer circuit below.
C01
IN'
R01
R02 C02
R04
R03 C03
C04
EQP 3
EQN 4
60k
2
IN
60k
−
+
VREF1
The frequency response of the equalizer circuit is given by the following equation, where ƒ is the frequency.
1
1₊
1
+ ¹ + 2πƒC04
60000 _{R03 +} 1
R04
2πƒC03
Response = 20 × log₁₀
[dB]
1₊
1
2πƒC01
1 ₊1₊
1
60000 R01 _{R02 + 1}
2πƒC02
Dynamic Range Compression Mode (TM1, TM2)
The dynamic range compression mode is selected by the state of the TM1 and TM2 inputs. When a compres-
sion mode is used, the gain for small input signals is increased while large input signals are converted using a
curve that performs soft-clipping. This increases the average sound pressure level emitted from the speaker
during playback.
Dynamic range compression
mode
TM1
OFF
L
1
H
2
L
3
H
TM2
Effect
L
No effect
L
Small effect
H
Medium effect
H
Large effect
NIPPON PRECISION CIRCUITS INC.—8