WM8737LGEFL/R Wolfson Microelectronics, WM8737LGEFL/R Datasheet - Page 17

• Manufacturer Part Number: WM8737LGEFL/R
• Description: IC, ADC, 24BIT, 96KHZ, QFN-32
• Manufacturer: Wolfson Microelectronics

Specifications of WM8737LGEFL/R

• Resolution (bits): 24bit
• Sampling Rate: 96kSPS
• Data Interface: 2-Wire, 3-Wire, Serial
• Supply Voltage Range - Analog: 1.8V To 3.6V
• Supply Current: 7.75mA
• Digital Ic Case Style: QFN
• No. Of Pins: 32
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Production Data
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Table 5 Mono Mixing Control
Note: In stereo mode (R5) 00, Bit 1 must always be set to 0.
MICROPHONE BIAS
The MICBIAS output provides a low noise reference voltage suitable for biasing electret type
microphones and the associated external resistor biasing network. The output voltage is derived from
VREF and is programmable in three steps from 0.75 × AVDD to 1.2 × AVDD, as shown below.
Supply voltage MVDD must be at least 170mV higher than the desired MICBIAS voltage to ensure
correct MICBIAS operation.
Table 6 MICBIAS Control
The internal MICBIAS circuitry is shown below. MVDD is a separate power supply pin used only for
MICBIAS and the microphone preamplifiers. When MICBIAS < AVDD, then MVDD can be tied to
AVDD. However, when MICBIAS = 1.2 × AVDD, then MVDD must be large enough to generate this
output voltage, i.e. it must be higher than AVDD.
Note: The maximum voltage for MVDD of 3.6V must be observed.
Figure 6 Microphone Bias Schematic
Note that the maximum source current capability for MICBIAS is 3mA. The external biasing resistors
therefore must be large enough to limit the MICBIAS current to 3mA. Please refer to the
“Applications Information” section for recommended external components.
R5 (05h)
ADC Control
R5 (05h)
ADC Control
R6 (06h)
Power
Management
REGISTER
ADDRESS
REGISTER
ADDRESS
VREF
BIT
8:7
1
MVDD
BIT
1:0
MONOMIX[1:0]
MONOUT
MICBIAS[1:0]
LABEL
LABEL
AGND
internal
resistor
DEFAULT
DEFAULT
00
0
00
MICBIAS
00: Stereo
01: Analogue Mono-mix
10: Digital Mono-mix
11: Reserved
Analogue mono-mix format control
0: Left ADC data appears on Left
Channel output and Right ADC data
appears on Right Channel Output.
1: Left ADC data appears on both Left
and Right channel outputs.
Microphone Bias Control
00: MICBIAS OFF (powered down,
high-impedance output)
01: V
10: V
11: V
MICBIAS
MICBIAS
MICBIAS
DESCRIPTION
= 0.75 × AVDD
= 0.9 × AVDD
= 1.2 × AVDD
DESCRIPTION
PD, Rev 4.1, April 2009
WM8737L
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