WM8143-12 Wolfson Microelectronics Ltd., WM8143-12 Datasheet - Page 12

• Manufacturer Part Number: WM8143-12
• Description: WM8143 : 10 or 12-BIT, 4MSPS Analogue Front End For CCD Image Sensors
• Manufacturer: Wolfson Microelectronics Ltd.

WM8143-12
When the VS/RS control is activated the switch closes
and the effective impedance of the input is 1/CF where
the value of C changes from 0.3pF for minimum gain to
9.6pF for maximum gain and F is the sample frequency
in Hz. Table 2 illustrates the maximum and minimum
input impedance at different frequencies.
Table 2 Effects of Frequency on Input Impedance
Calibration
To achieve optimum performance of the WM8143-12, a
calibration procedure must be implemented. This is
achieved by using a combination of the gain and offset
functions to amplify and shift the input signal so that it
lies within and maximises the input ADC range.
FREQUENCY
SAMPLING
(MHz)
0.5
1
2
4
IMPEDANCE
(M ) MIN
GAIN
6.6
3.3
1.6
0.8
Wolfson Microelectronics
IMPEDANCE
(K ) MAX
GAIN
208
104
52
26
12
PD. Rev 4 Nov. 99
Production Data