The SN74LVTH16543 is a 16bit registered transceiver designed for lowvoltage (3.3V) VCC operation, but with the capability to provide a TTL interface to a 5V system environment. This device can be used as two 8bit transceivers or one 16bit transceiver. Separate latchenable (LEAB or LEBA) and outputenable (OEAB or OEBA) inputs are provided for each register to permit independent control in either direction of data flow.
The AtoB enable (CEAB) input must be low to enter data from A or to output data from B. If CEAB is low and LEAB is low, the AtoB latches are transparent; a subsequent lowtohigh transition of LEAB puts the A latches in the storage mode. With CEAB and OEAB both low, the 3state B outputs are active and reflect the data present at the output of the A latches. Data flow from B to A is similar, but requires using the CEBA, LEBA, and OEBA inputs.
Active bushold circuitry is provided to hold unused or floating data inputs at a valid logic level.
When VCC is between 0 and 1.5 V, the device is in the highimpedance state during power up or power down. However, to ensure the highimpedance state above 1.5 V, OE should be tied to VCC through a pullup resistor; the minimum value of the resistor is determined by the currentsinking capability of the driver.
This device is fully specified for hotinsertion applications using Ioff and powerup 3state. The Ioff circuitry disables the outputs, preventing damaging current backflow through the device when it is powered down. The powerup 3state circuitry places the outputs in the highimpedance state during power up and power down, which prevents driver conflict.
The SN74LVTH16543 is a 16bit registered transceiver designed for lowvoltage (3.3V) VCC operation, but with the capability to provide a TTL interface to a 5V system environment. This device can be used as two 8bit transceivers or one 16bit transceiver. Separate latchenable (LEAB or LEBA) and outputenable (OEAB or OEBA) inputs are provided for each register to permit independent control in either direction of data flow.
The AtoB enable (CEAB) input must be low to enter data from A or to output data from B. If CEAB is low and LEAB is low, the AtoB latches are transparent; a subsequent lowtohigh transition of LEAB puts the A latches in the storage mode. With CEAB and OEAB both low, the 3state B outputs are active and reflect the data present at the output of the A latches. Data flow from B to A is similar, but requires using the CEBA, LEBA, and OEBA inputs.
Active bushold circuitry is provided to hold unused or floating data inputs at a valid logic level.
When VCC is between 0 and 1.5 V, the device is in the highimpedance state during power up or power down. However, to ensure the highimpedance state above 1.5 V, OE should be tied to VCC through a pullup resistor; the minimum value of the resistor is determined by the currentsinking capability of the driver.
This device is fully specified for hotinsertion applications using Ioff and powerup 3state. The Ioff circuitry disables the outputs, preventing damaging current backflow through the device when it is powered down. The powerup 3state circuitry places the outputs in the highimpedance state during power up and power down, which prevents driver conflict.