ZHCSRE9C August 2005 – December 2022 SN74LVCH8T245
PRODUCTION DATA
The output-enable (OE) input circuit is designed so that it is supplied by VCCA and when the OE input is high, all outputs are placed in the high-impedance state. To ensure the high-impedance state of the outputs during power up or power down, the OE input pin must be tied to VCCA through a pullup resistor and must not be enabled until VCCA and VCCB are fully ramped and stable. The minimum value of the pullup resistor to VCCA is determined by the current-sinking capability of the driver.
VCCA or VCCB can
be powered up first. If the SN74LVCH8T245 is powered up in a permanently
enabled state
(for example OE is
always kept low), pullup resistors are recommended at the input. This ensures
proper, glitch-free, power-up. For more information, see Designing with
SN4LVCXT245 and SN74LVCHXT245 Family of Direction Controlled Voltage
Translators/Level-Shifters. In addition, the
OE pin may be shorted to GND if the application does not
require use of the high-impedance state at any time.