WM8533 datasheet(26/41 Pages) WOLFSON

Part #	WM8533

Description	24-bit 192kHz Stereo DAC with 2Vrms Ground Referenced Line Output

PDF	41 Pages

Scroll/Zoom	100%

Manufacturer	WOLFSON [Wolfson Microelectronics plc]

Direct Link	http://www.wolfsonmicro.com

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26 / 41 page

WM8533

Production Data

PD, July 2012, Rev 4.0

The effect of the volume ramp is illustrated in Figure 23.

Figure 23 Volume Ramp Functionality

Ramp Volume Changes

If ramp volume changes are selected, the ramp rate is dependent upon the sampling rate. The ramp

rates for common audio sample rates are shown in Table 15.

SAMPLE RATE FOR DAC (kHz)

GAIN RAMP RATE

(ms/dB)

0.25

44.1

0.18

0.17

88.2

0.1

0.08

176.4

0.05

192

0.04

Table 15 Volume Ramp Rate

For example, when using a sample rate of 48kHz, the time taken for a volume change from an initial

setting of 0dB to -20dB is calculated as follows:

Volume Change (dB) x Volume Ramp Rate (ms/dB) = 20 x 0.17 = 3.4ms

Zero cross is not used when ramping. The volume level in the DAC is set by the user in 0.25dB

increments, but during the volume ramp increments of 0.125dB are actually used. This step size is

inaudible and means there is no requirement to wait until a zero crossing occurs. Another benefit of

not using zero cross when ramping is that predictable ramp times are produced – there is no signal

dependency on the ramp time.

WM8533 Datasheet(PDF) 26 Page - Wolfson Microelectronics plc