CVMEH22501AIDGGREP

增强型产品 8 位通用总线收发器和 2 个 1 位总线收发器 48-TSSOP -40 to 85

The SN74VMEH22501A-EP 8-bit universal bus transceiver has two integral 1-bit three-wire bus transceivers and is designed for 3.3-V VCC operation with 5-V tolerant inputs. The UBT transceiver allows transparent, latched, and flip-flop modes of data transfer, and the separate LVTTL input and outputs on the bus transceivers provide a feedback path for control and diagnostics monitoring. This device provides a high-speed interface between cards operating at LVTTL logic levels and VME64, VME64x, or VME3202 backplane topologies.

The SN74VMEH22501A-EP device is pin-for-pin compatible to the SN74VMEH22501 device SCES357, but operates at a wider operating temperature range.

High-speed backplane operation is a direct result of the improved OEC circuitry and high drive that has been designed and tested into the VME64x backplane model. The B-port I/Os are optimized for driving large capacitive loads and include pseudo-ETL input thresholds ½ VCC ±50 mV for increased noise immunity. These specifications support the 2eVME protocols in VME64x ANSI/VITA 1.1 and 2eSST protocols in VITA 1.5.

With proper design of a 21-slot VME system, a designer can achieve 320-MB transfer rates on linear backplanes and, possibly, 1-GB transfer rates on the VME320 backplane.

All inputs and outputs are 5-V tolerant and are compatible with TTL and 5-V CMOS inputs.

Active bus-hold circuitry holds unused or undriven 3A-port inputs at a valid logic state. Bus-hold circuitry is not provided on 1A or 2A inputs, any B-port input, or any control input. Use of pullup or pulldown resistors with the bus-hold circuitry is not recommended.

This device is fully specified for live-insertion applications using Ioff, power-up 3-state, and BIAS VCC. The Ioff circuitry prevents damaging current to backflow through the device when it is powered off/on. The power-up 3-state circuitry places the outputs in the high-impedance state during power up and power down, which prevents driver conflict. The BIAS VCC circuitry precharges and preconditions the B-port input/output connections, preventing disturbance of active data on the backplane during card insertion or removal, and permits true live-insertion capability.

When VCC is between 0 and 1.5 V, the device is in the high-impedance state during power up or power down. However, to ensure the high-impedance state above 1.5 V, output-enable OE and OEBY inputs should be tied to VCC through a pullup resistor and output-enable OEAB inputs should be tied to GND through a pulldown resistor; the minimum value of the resistor is determined by the drive capability of the device connected to this input.