WM9090ECS/R Wolfson Microelectronics, WM9090ECS/R Datasheet - Page 26

• Manufacturer Part Number: WM9090ECS/R
• Description: Audio CODECs Audio Subsystem w/ capless headphones
• Manufacturer: Wolfson Microelectronics

Specifications of WM9090ECS/R

• Interface Type: 2-Wire, l2C
• Thd Plus Noise: 80 dB
• Ic Function: Ultra Low Power Audio Subsystem
• Brief Features: Mono Class D Speaker Driver, Automatic Gain Control (AGC)
• Supply Voltage Range: 2.7V To 5.5V
• Operating Temperature Range: -40°C To +85°C
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

WM9090
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When the AGC applies signal attenuation triggered by the anti-clip threshold, the signal gain is
reduced at a rate that is set by the AGC_CLIP_ATK register. When the anti-clip threshold is no
longer met (due to the signal level reduction), then the AGC increases the signal gain at a rate set by
the AGC_CLIP_DCY register.
Note that, when the anti-clip and power limiting thresholds are both triggered concurrently, then the
signal gain is reduced at the rate set by the AGC_CLIP_ATK register and is increased at the rate set
by AGC_PWR_DCY. These fields are defined in Table 13 and Table 14 respectively.
Table 13 AGC Anti-Clip Control
R98 (62h)
AGC Control
0
REGISTER
ADDRESS
11:8
BIT
6:4
2:0
15
AGC_CLIP_ENA
AGC_CLIP_THR [3:0]
AGC_CLIP_ATK [2:0]
AGC_CLIP_DCY [2:0]
LABEL
DEFAULT
0110
100
000
1
Enable AGC Anti-Clip Mode
0 = Disabled
1 = Enabled
AGC Anti-Clip Threshold
Sets the headroom between
SPKPGA output and SPKVDD at
which Anti-Clip limiting will be
applied
0000 = -200mV
0001 = -150mV
0010 = -100mV
0011 = -50mV
0100 = 0mV
0101 = 50mV
0110 = 100mV
0111 = 150mV
1000 = 200mV
1001 = 250mV
1010 = 300mV
1011 = 400mV
1100 = 500mV
1101 = 600mV
1110 = 700mV
1111 = 800mV
AGC Anti-Clip Attack Rate
Sets the rate of AGC gain reduction
when clipping is detected
000 = 0.6ms/6dB
001 = 5.4ms/6dB
010 = 10.2ms/6dB
011 = 15.0ms/6dB
100 = 19.8ms/6dB
101 = 24.6ms/6dB
110 = 29.4ms/6dB
111 = 34.1ms/6dB
AGC Anti-Clip Decay Rate
Sets the rate of AGC gain
increments after a period of clipping
000 = 120ms/6dB
001 = 480ms/6dB
010 = 820ms/6dB
011 = 1170ms/6dB
100 = 1640ms/6dB
101 = 2050ms/6dB
110 = 2730ms/6dB
111 = 4100ms/6dB
PP, January 2010, Rev 3.0
DESCRIPTION
Pre-Production
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