20
0
–20
–40
–60
–80
–100
–120
–140
100
1k
10k
FREQUENCY (Hz)
Figure 10. IMD for 19 kHz/20 kHz Twin-Tone Stimulus with
500 mW Power in Each Tone
40
35
PGA GAIN = 18dB
30
PGA GAIN = 12dB
25
PGA GAIN = 6dB
20
PGA GAIN = 0dB
15
10
5
0
100
1k
10k
FREQUENCY (Hz)
Figure 11. Amplifier Gain vs. Frequency, 6 Ω Load, PVDD = 12 V
0
–20
–40
–60
–80
L CHANNEL IDLE,
R CHANNEL DRIVEN
–100
–120
L CHANNEL DRIVEN,
R CHANNEL IDLE
100
1k
10k
FREQUENCY (Hz)
Figure 12. Channel Separation vs. Frequency, Driven Channel Has
1 W Output Power into 6 Ω Load
AD1990
1
–40
–50
0.1
–60
–70
0.01
–80
–90
0.001
–100
0.0001
100
1k
FREQUENCY (Hz)
–110
–120
10k
Figure 13. THD vs. Frequency, 1 W Output Power into 4 Ω Load, PVDD = 12 V
1
–40
–50
0.1
–60
–70
0.01
–80
–90
0.001
–100
–110
0.0001
100
1k
FREQUENCY (Hz)
–120
10k
Figure 14. THD vs. Frequency, 1 W Output Power into 6 Ω Load, PVDD = 12 V
1
–40
–50
0.1
–60
–70
0.01
–80
–90
0.001
–100
–110
0.0001
100
1k
FREQUENCY (Hz)
–120
10k
Figure 15. THD vs. Frequency, 1 W Output Power into 8 Ω Load, PVDD = 12 V
Rev. 0 | Page 9 of 16