These octal transceivers are designed specifically for low-voltage (3.3-V) VCC operation, but with the capability to provide a TTL interface to a 5-V system environment.
The LVTH543 devices contain two sets of D-type latches for temporary storage of data flowing in either direction. Separate latch-enable (LEAB\ or LEBA\) and output-enable (OEAB\ or OEBA\) inputs are provided for each register, to permit independent control in either direction of data flow.
The A-to-B 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 A-to-B latches are transparent; a subsequent low-to-high transition of LEAB\ puts the A latches in the storage mode. With CEAB\ and OEAB\ both low, the 3-state 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 bus-hold circuitry holds unused or undriven inputs at a valid logic state. Use of pullup or pulldown resistors with the bus-hold circuitry is not recommended.
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, OE\ should be tied to VCC through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.
This device is fully specified for hot-insertion applications using Ioff and power-up 3-state. The Ioff circuitry disables the outputs, preventing damaging current backflow through the device when it is powered down. The power-up 3-state circuitry places the outputs in the high-impedance state during power up and power down, which prevents driver conflict.
|Part number||Order||Technology Family||VCC (Min) (V)||VCC (Max) (V)||Bits (#)||Voltage (Nom) (V)||F @ nom voltage (Max) (MHz)||ICC @ nom voltage (Max) (mA)||tpd @ nom Voltage (Max) (ns)||IOL (Max) (mA)||IOH (Max) (mA)||Operating temperature range (C)||Package Group|
||LVT||2.7||3.6||8||3.3||160||0.005||3.7||64||-32||-40 to 85||
SOIC | 24
SO | 24
SSOP | 24
TSSOP | 24