The SN74FB2031 is a 9-bit transceiver designed to translate signals between TTL and backplane transceiver logic (BTL) environments. The device is designed specifically to be compatible with IEEE Std 1194.1-1991.

The B\ port operates at BTL-signal levels. The open-collector B\ ports are specified to sink 100 mA. Two output enables (OEB and OEB\) are provided for the B\ outputs. When OEB is low, OEB\ is high, or VCC is less than 2.1 V, the B\ port is turned off.

The A port operates at TTL signal levels. The A outputs reflect the inverse of the data at the B\ port when the A-port output enable (OEA) is high. When OEA is low or VCC is less than 2.1 V, the A outputs are in the high-impedance state.

Pins are allocated for the four-wire IEEE Std 1149.1 (JTAG) test bus, although currently there are no plans to release a JTAG-featured version. TMS and TCK are not connected and TDI is shorted to TDO.

BIAS VCC establishes a voltage between 1.62 V and 2.1 V on the BTL outputs when VCC is not connected.

BG VCC and BG GND are the supply inputs for the bias generator.

• Compatible With IEEE Std 1194.1-1991 (BTL)
• TTL A Port, Backplane Transceiver Logic (BTL) B\ Port
• Open-Collector B\-Port Outputs Sink 100 mA
• High-Impedance State During Power Up and Power Down
• BIAS VCC Minimizes Signal Distortion During Live Insertion or Withdrawal
• B\-Port Biasing Network Preconditions the Connector and PC Trace to the BTL High-Level Voltage
• TTL-Input Structures Incorporate Active Clamping to Aid in Line Termination