QUAD FUTUREBUS BACKPLANE TRANSCEIVER (3 STATE + OPEN COLLECTOR)

The MC74F3893A is a quad backplane transceiver and is intended to be used in very high speed bus systems.

The MC74F3893A interfaces to “Backplane Transceiver Logic” (BTL). BTL features a reduced (1 V) voltage swing for lower power consumption and a series diode on the drivers to reduce capacitive loading (< 5 pF). Incident wave switching is employed, therefore BTL propagation delays are short. Although the voltage swing is much less for BTL, so is its receiver threshold region, therefore noise margins are excellent.

BTL offers low power consumption, low ground bounce, reduced EMI and crosstalk, low capacitive loading, superior noise margin and short propagation delays. This results in a high bandwidth, reliable backplane.

The MC74F3893A has four TTL outputs (Rn) on the receiver side with a commonReceive Enable input (RE). It has four data inputs (Dn) which are also TTL. These data inputs are NANDed with the Data Enable input (DE). The four I/O pins (Bus side) are futurebus compatible, sink a minimum of 100 mA, and are designed to drive heavily loaded backplanes with load impedances as low as 10 ohms. All outputs are designed to be glitch-free during power up and power down.

• Quad Backplane Transceiver

• Drives Heavily Loaded Backplanes with Equivalent Load Impedances Down to 10 ohms

• Futurebus Drivers Sink 100 mA

• Reduced Voltage Swing (1 Volt) Produces Less Noise and Reduces Power Consumption

• High Speed Operation Enhances Performance of Backplane Buses and Facilitates Incident Wave Switching

• Compatible with IEEE 896 and IEEE 1194.1 Futurebus Standards

• Built-In Precision Band-Gap (BG) Reference Provides Accurate Receiver Threshold and Improved Noise Immunity

• Glitch-Free Power Up/Power Down Operation On All Outputs

• Pin and Function Compatible with NSC DS3893A and Signetics 74F3893

• Separate Bus Ground Returns for Each Driver to Minimize Ground Noise

• MOS and TTL Compatible High Impedance Inputs