WM8983GEFL/V Wolfson Microelectronics, WM8983GEFL/V Datasheet - Page 79

• Manufacturer Part Number: WM8983GEFL/V
• Description: Audio CODECs Mbl Multimedia CODEC w/ 1W Speaker Driver
• Manufacturer: Wolfson Microelectronics

Specifications of WM8983GEFL/V

• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: QFN-32
• Minimum Operating Temperature: - 25 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Production Data
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UNUSED ANALOGUE INPUTS/OUTPUTS
Table 53 Disabled Outputs to VREF Resistance
Figure 41 Unused Input/Output Pin Tie-off Buffers
Whenever an analogue input/output is disabled, it remains connected to a voltage source (either
AVDD1/2 or 1.5xAVDD1/2 as appropriate) through a resistor. This helps to prevent pop noise when
the output is re-enabled. The resistance between the voltage buffer and the output pins can be
controlled using the VROI control bit. The default impedance is low, so that any capacitors on the
outputs can charge up quickly at start-up. If a high impedance is desired for disabled outputs, VROI
can then be set to 1, increasing the resistance to about 30kΩ.
A dedicated buffer is available for biasing unused analogue I/O pins as shown in Figure 41. This
buffer can be enabled using the BUFIOEN register bit.
If the SPKBOOST, OUT3BOOST or OUT4BOOST bits are set then the relevant outputs will be tied
to the output of the DC level shift buffer at 1.5xAVDD/2 when disabled.
Figure 41 summarises the bias options for the output pins.
R49
REGISTER
ADDRESS
0
BIT
VROI
LABEL
0
DEFAULT
VREF (AVDD1/2 or 1.5xAVDD/2) to
analogue output resistance
0: approx 1kΩ
1: approx 30 kΩ
DESCRIPTION
PD, Rev 4.3, May 2010
WM8983
79