12-Bit AFE Works With 8-Msample/s Sensors

The WM8150, a single-channel, 12-bit analog front end (AFE) with 4-bit output, is compatible with contact image sensor (CIS) or charge-coupled device (CCD) sensors at a pixel sample rate up to 8 Msamples/s. The AFE targets flatbed scanner and multi-function peripheral applications. The signal path includes reset level clamping, correlated double sampling, programmable gain, and offset-adjust functions. Using on-chip registers and multiplexers, the values of the offset digital-to-analog converter (DAC) and programmable gain amplifier (PGA) can be reset to ease the processing of line-by-line RGB color information. The PGA is monotonic over an 8-bit range. Its input voltage ranges from 0.3 to 3.22 V for full-scale digital output at maximum or minimum gain, respectively. Overall differential nonlinearity (DNL) is typically 0.5 LSB, and integral nonlinearity (INL) is 2 LSB. Current consumption measures 45 mA maximum. The WM8150 is available in a 20-lead SSOP and starts at $1.15 in 10,000-unit quantities.

Wolfson Microelectronics Ltd.
www.wolfsonmicro.com; +44 (0) 131 667 9386