ssm2317 Analog Devices, Inc., ssm2317 Datasheet - Page 16

• Manufacturer Part Number: ssm2317
• Description: Filterless High Efficiency Mono 3 W Class-d Audio Amplifier
• Manufacturer: Analog Devices, Inc.

SSM2317
OUTPUT THRESHOLD
The maximum output amplitude threshold (V
limiting mode can be changed from 90% to 45% of V
having an external resistor, R
Shorting the VTH pin to GND sets V
the VTH pin unconnected sets V
of R
Maximum output power is derived from V
equation:
where R
Figure 43 shows the relationship between the R
V
output power and the R
TH
. Figure 44 shows the relationship between the maximum
TH
V
P
OUT
100
TH
to V
90
80
70
60
50
40
SP
0.1
=
is the speaker impedance.
=
TH
0
⎛
⎜
⎝
9 .
is shown by the following equation:
V
×
R
Figure 43. Output Threshold (V
TH
2
SP
50
50
1
⎞
⎟
⎠
2
kΩ
kΩ
+
TH
+
2
value.
×
R
10
TH
R
TH
R
TH
, between the VTH pin and GND.
TH
TH
×
(kΩ)
V
to 45% of V
DD
100
TH
to 90% of V
TH
) vs. R
TH
by the following
TH
1k
TH
TH
DD
) during the
. The relation
value and
DD
DD
. Leaving
by
10k
Rev. A | Page 16 of 20
ENABLE/DISABLING ALC
The ALC function is enabled when the ALC_EN pin is set to
V
amplifier operation. As a result of enabling ALC, I
by 100 μA and there is less than 50 μA source current from the
VTH pin to GND via R
current is 0 μA and the VTH pin is tied to GND.
DD
. The ACL function can be enabled and disabled during
1400
1200
1000
800
600
400
200
0
0.1
Figure 44. Maximum Output Power vs. R
3.6V (8Ω)
2.5V (8Ω)
1
4.2V (8Ω)
5V (8Ω)
TH
. When ALC is disabled, the source
10
R
TH
(kΩ)
100
1k
TH
SY
increases
10k