SN54LVT639, SN74LVT639
3.3-V ABT OCTAL BUS TRANSCEIVERS
WITH 3-STATE (B PORT) AND OPEN-COLLECTOR (A PORT) OUTPUTS

SCBS475A - JUNE 1994 - REVISED JULY 1995

features

• State-of-the-Art Advanced BiCMOS Technology (ABT) Design for 3.3-V Operation and Low-Static Power Dissipation
• A-Bus Outputs Are Open Collector;
  B-Bus Outputs Are 3 State
• Support Mixed-Mode Signal Operation (5-V Input and Output Voltages With 3.3-V V_CC)
• Support Unregulated Battery Operation Down to 2.7 V
• Typical V_OLP (Output Ground Bounce) < 0.8 V at V_CC = 3.3 V, T_A = 25°C
• Latch-Up Performance Exceeds 500 mA Per JEDEC Standard JESD-17
• Bus-Hold Data Inputs (B Port) Eliminate the Need for External Pullup Resistors
• Support Live Insertion
• Package Options Include Plastic Small-Outline (DW), Shrink Small-Outline (DB), and Thin Shrink Small-Outline (PW) Packages, Ceramic Chip Carriers (FK), and Ceramic (J) DIPs

description

These octal bus transceivers are designed specifically for low-voltage (3.3-V) V_CC operation, but with the capability to provide a TTL interface to a 5-V system environment.

These ´LVT639 are designed for asynchronous communication between open-collector and 3-state buses. These devices transmit data from the A bus (open collector) to the B bus (3 state) or from the B bus to the A bus, depending upon the logic level at the direction-control (DIR) input. The output-enable () input can be used to disable the device so the buses are effectively isolated.

Active bus-hold circuitry is provided on the B bus to hold unused or floating data inputs at a valid logic level.

To ensure the high-impedance state during power up or power down, should be tied to V_CC through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.

The SN74LVT639 is available in TI's shrink small-outline package (DB), which provides the same I/O pin count and functionality of standard small-outline packages in less than half the printed-circuit-board area.

The SN54LVT639 is characterized for operation over the full military temperature range of -55°C to 125°C. The SN74LVT639 is characterized for operation from -40°C to 85°C.