WM8959
Pre-Production
SPEAKER DRIVER PERFORMANCE
Typical speaker driver THD+N performance is shown below for both Class D and Class AB modes. Curves are shown for
four typical SPKVDD supply voltage and gain combinations.
Load RL = 8Ω + 10µH, Frequency = 1kHz, +1dB gain in active path.
SPEAKER CLASS D INTO 8Ω + 10µH
SPEAKER CLASS AB INTO 8Ω + 10µH
Speaker Class D (8 +10 H)
THD+N Ratio v Output Power
Speaker Class AB (8 +10 H)
Ω µ
THD+N Ratio v Output Power
Ω
µ
10
10
1
1
0.1
0.1
0.01
0.01
SPKVDD=5.0V, AC=DC=1.52x
SPKVDD=4.2V, AC=DC=1.27x
SPKVDD=3.6V, AC=DC=1.00x
SPKVDD=3.3V, AC=DC=1.00x
SPKVDD=5.0V, AC=DC=1.52x
SPKVDD=4.2V, AC=DC=1.27x
SPKVDD=3.6V, AC=DC=1.00x
SPKVDD=3.3V, AC=DC=1.00x
0.001
0.001
0
0.25
0.5
0.75
1
1.25
1.5
0
0.25
0.5
0.75
1
1.25
1.5
Output Power (W)
Output Power (W)
HEADPHONE DRIVER PERFORMANCE
Typical THD+N performance of the Headphone Drivers is shown below (AC coupled to LOUT/ROUT). Curves are shown
for four HPVDD/AVDD supply voltages.
Load RL = 16Ω and 32Ω, Frequency = 1kHz, +1dB gain in active path.
AC COUPLED HEADPHONE INTO 16Ω
AC COUPLED HEADPHONE INTO 32Ω
AC Coupled Headphone (16ohm)
THD+N Ratio v Output Power
AC Coupled Headphone (32ohm)
THD+N Ratio v Output Power
10
10
1
1
0.1
0.1
HPVDD=AVDD=3.6V
HPVDD=AVDD=3.6V
HPVDD=AVDD=3.3V
HPVDD=AVDD=3.0V
HPVDD=AVDD=2.7V
HPVDD=AVDD=3.3V
HPVDD=AVDD=3.0V
HPVDD=AVDD=2.7V
0.01
0.01
0
10
20
30
40
50
60
70
80
0
10
20
30
40
50
60
70
80
Output Power (mW)
Output Power (mW)
PP, May 2008, Rev 3.1
22
w
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
