LF48908

Storage temperature .......................................................65 to +150
Operating ambient temperature .......................................55 to +125
VCC supply voltage with respect to ground ..................... 0.5 V to +7.0 V
Input signal with respect to ground ........................ 0.5 V to VCC + 0.5 V
Signal applied to high impedance output ................ 0.5 V to VCC + 0.5 V
Output current into low outputs .........................................................25 mA
Latchup current ............................................................................. > 400 mA

The LF48908 is a high-speed two dimensional convolver that implements a 3 x 3 kernel convolution at real-time video rates. Programmable row buffers are located on-chip, eliminating the need for external data storage. Each row buffer can store up to 1024 pixels. Two internal register banks are provided allowing two separate sets of filter coefficients to be stored simultaneously. Adaptive filter operations are possible when both register banks are used. An on-chip ALU is provided, allowing real-time arithmetic and logical pixel point operations to be performed on the image data. The 3 x 3 convolver comprises nine 8 x 8-bit multipliers, various pipeline registers, and summers.

A complete sum-of-products operation is performed every clockcycle. The FRAME signal resets all data registers without affecting the control and coefficient registers.

Pixel and coefficient input data are both 8-bits and can be either signed or unsigned integers. Image data should be in a raster scan non-interlaced format. The LF48908 can internally store images as wide as 1024 pixels for the 3 x 3 convolution. By using external row buffers and multiple LF48908s, longer pixel rows can be used and convolutions with larger kernel sizes can be performed. Output data is 20-bits and this guarantees no overflow for kernel sizes up to 4 x 4.

A separate cascade input is used as the data input for summing results from multiple LF48908s. It can also function as the data input path when external line buffers are used.