SSM2317 datasheet(16/20 Pages) AD

16 / 20 page

SSM2317

Rev. A | Page 16 of 20

OUTPUT THRESHOLD

1400

1200

1000

800

600

400

200

0.1

100

10k

RTH (kΩ)

5V (8Ω)

4.2V (8Ω)

3.6V (8Ω)

2.5V (8Ω)

The maximum output amplitude threshold (VTH) during the

limiting mode can be changed from 90% to 45% of VDD by

having an external resistor, RTH, between the VTH pin and GND.

Shorting the VTH pin to GND sets VTH to 90% of VDD. Leaving

the VTH pin unconnected sets VTH to 45% of VDD. The relation

of RTH to VTH is shown by the following equation:

kΩ

Maximum output power is derived from VTH by the following

equation:

OUT

⎟

⎠

⎞

⎜

⎝

⎛

Figure 44. Maximum Output Power vs. RTH

ENABLE/DISABLING ALC

where RSP is the speaker impedance.

The ALC function is enabled when the ALC_EN pin is set to

VDD. The ACL function can be enabled and disabled during

amplifier operation. As a result of enabling ALC, ISY increases

by 100 μA and there is less than 50 μA source current from the

VTH pin to GND via RTH. When ALC is disabled, the source

current is 0 μA and the VTH pin is tied to GND.

Figure 43 shows the relationship between the RTH value and

VTH. Figure 44 shows the relationship between the maximum

output power and the RTH value.

100

0.1

100

10k

RTH (kΩ)

Figure 43. Output Threshold (VTH) vs. RTH

SSM2317 Datasheet(PDF) 16 Page - Analog Devices

SSM2317 Datasheet(HTML) 16 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Datasheet Download

Link URL