TC90A60U

The TC90A60U is an IC for capturing Japan teletext and data broadcast (also EIA-516) signals superposed on video signals. Its main functions include sync separation,equalization, data and sampling clock generation, and error correction.When connected in parallel to a microcontroller, the IC allows data capturing with a relatively small part count.

Features of the TC90A60U are:(1)digital regeneration of Japan eletext and data broadcast(also EIA-516) data using a built-in AD converter; (2)equalization using a 13-tap transversal filter(equalization range:-0.5~1.5 s); (3)buffer memory which accommodate 8 data packets; (4)error correction circuit; (5)framing code detection; (6)sync separator circuit; (7)parallel interface (8 bits for data, 4 bits for address and 3 bits for control); (8)3.3 V single power supply.In this mode framing code detection pulses are regenerated consecutively. The detection pulses are protected for the last 3 packets and first 2 packets. Hence, if framing code mismatch occurs in a consecutive three packets Real-Time Regeneration Mode will be automatically selected, after which if framing code mismatch does not occur for a consecutive two packets Consecutive Regeneration Mode will be selected again.

The absolute maximum ratings of the TC90A60U can be summarized as:(1)power supply voltage:Vss to Vss+4.5 V;(2)input voltage:-0.3 to Vdd+0.3V;(3)storage temperature:-55 to 125;(4)power dissipation:520mW.TC90A60U incorporates 8 line buffers, each of which consists of 35 bytes.Each line buffer corresponds to a single data line:which line buffer corresponds to which data line can be set in software. A single data line cannot be set to be captured into multiple line buffers. Thus it is not allowed, for instance, to capture 10H into all the 8 line buffers.TC90A60U is not capable of accumulating more than 1-field data. A set of data usually extends continuously across many fields. Thus capturing such a set of data requires field-by-field access to TC90A60U and storing the captured data in a larger external memory.TC90A60U incorporates a sync separation circuit to extract composite sync signals from luminance signals. It also incorporates a Sync-Tip Clamp to allow video input signals to be sliced at a fixed voltage and thereby sync signals to be generated. The slice level is automatically switched between two modes according to the Sync amplitude.