WM8224 datasheet(22/50 Pages) WOLFSON

Part #	WM8224

Description	60MSPS 3-Channel AFE with Multiple Device Operation and Programmable Automatic Black Level Calibration

PDF	50 Pages

Scroll/Zoom	100%

Manufacturer	WOLFSON [Wolfson Microelectronics plc]

Direct Link	http://www.wolfsonmicro.com

Logo

22 / 50 page

WM8224

Production Data

PD, Rev 4.1, June 2012

128

256

384

512

Gain Code (PGA[8:0])

0.5

1.5

2.5

3.5

128

256

384

512

Gain Code (PGA[8:0])

Max i/p Voltage

LOWREFS=0

Max i/p Voltage

LOWREFS=1

Figure 17 PGA Gain Characteristic

Figure 18 Peak Input Voltage to Match ADC Full-scale Range

ADC INPUT BLACK LEVEL ADJUST

The output from the PGA can be offset to match the full-scale range of the differential ADC (2*[VRT-

VRB]).

For negative-going input video signals, a black level (zero differential) output from the PGA should be

offset to the top of the ADC range by setting register bits PGAFS[1:0]=10. This will give an output

code of FFFF (hex) from the WM8224 for zero input. If code zero is required for zero differential input

then the INVOP bit should be set.

For positive going input signals the black level should be offset to the bottom of the ADC range by

setting PGAFS[1:0]=11. This will give an output code of 0000 (hex) from the WM8224 for zero input.

Bipolar input video is accommodated by setting PGAFS[1:0]=00 or PGAFS[1:0]=01. Zero differential

input voltage gives mid-range ADC output, 7FFF (hex).

WM8224 Datasheet(PDF) 22 Page - Wolfson Microelectronics plc