AD2437

Rev. 0

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Page 29 of 42

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July 2023

Table 16. PDM Interface Performance Specifications

Parameter

Conditions

Min

Typ

Max

Unit

Dynamic Range with A-Weighted Filter

20 Hz to 20 kHz, –60 dBFS input

120

dB

SNR with A-Weighted Filter

20 Hz to 20 kHz

108

dB

Decimation Ratio1

Default is 64×

64×

256×

Frequency Response2

DC to 0.45 fSYNCM

–0.1

+0.01

dB

Stop Band

0.566

fSYNCM

Attenuation

74

dB

Group Delay

0.02 fSYNCM input signal

3.80

fSYNCM cycles

Gain

PDM to PCM

0

dB

Start-Up Time

3

48

fSYNCM cycles

Bit Width

Internal and output

24

Bits

1 The decimation ratio is controlled by the A2B_PDMCTL.PDMRATE field.

2 Measured with the high pass filter (HPF) disabled. Refer to Figure 23 for the frequency response with the HPF enabled at different cut-off frequencies.

3 The PDM start-up time is the time for the filters to settle after the PDM block is enabled. It is the time to wait before data is guaranteed to meet the specified performance.