WM8233: 6-channel high speed CCD/CIS ADC
The WM8233 is a 16-bit analogue front end/digitiser IC which processes and digitises the analogue output signals from CCD sensors or Contact Image Sensors (CIS) at pixel sample rates of up to 35MSPS.
The device has six analogue signal processing channels each of which contains Reset Level Clamping, Correlated Double Sampling (also Sample and Hold), Programmable Gain, Automatic Gain Control (AGC) and Offset adjust functions.
The output from each of these channels is time multiplexed, in pairs, into three high-speed 16-bit Analogue to Digital Converters. The digital data is available in a variety of output formats via the flexible data port.
The WM8233 has a user selectable LVDS or CMOS output architecture.
An internal 8-bit DAC is supplied for internal reference level generation. This may be used during CDS to reference CIS signals or during Clamping to clamp CCD signals. An external reference level may also be supplied. ADC references are generated internally, ensuring optimum performance from the device.
A programmable automatic Black-Level Calibration function is available to adjust the DC offset of the output data.
The WM8233 features a sensor timing clock generator for both CCD and CIS sensors. The clock generator can accept a slow or fast reference clock input and also has a flexible timing adjustment function for output timing clocks to allow use of many different sensors.
- 70MSPS conversion rate
- 16 bit ADC resolution
- Current consumption – 350mA
- 3.3V single supply operation
- Sample and hold /correlated double sampling
- Programmable offset adjust (8-bit resolution)
- Flexible clamp timing
- Pixel clamp / line clamp mode
- Programmable clamp voltage
- Programmable CIS/CCD timing generator
- Internally generated voltage references
- Compliant for Spread Spectrum Clock
- LVDS/CMOS output options
- LVDS 5pair 490MHz 35-bit data
- CMOS 90MHz output maximum
- Complete on chip clock generator. MCLK 5MHz to 35MHz
- Internal timing adjustment
- Automatic Gain Control
- Automatic Black Level Calibration
- 56-lead QFN package 8mm x 8mm
- Serial control interface