STMicroelectronics (headquartered in Geneva, Switzerland) is promoting eveloped a pair of low-voltage, high-speed transceiver ICs that conform to the IEEE1284 bi-directional parallel port interface standard. These devices target computer peripherals like printers, scanners and copiers.
The 74LVC161284TTR is a low-voltage, high-speed IEEE1284 transceiver. A "Z" version, the 74LVCZ161284ATTR is almost identical, but features an error-free power-up function as well. Each of these transceivers can replace the function of two previous-generation 74ACT1284 devices.
Both parts support both IEEE1284-I and -II (level one and level two) bi-directional parallel communications between personal computers and peripherals. A translation capability allows outputs on the cable side to interface with a 5V signal. A pull-up resistor is integrated on each open-drain output to eliminate the need for a discrete resistor to perform the same function.
The A port pins of the interface have standard 4mA totem-pole outputs. The B port pins offer the ability to source or sink up to 14mA. All the inputs offer a degree of hysteresis to improve their noise margin.
The parts have TTL-compatible inputs, despite working with operating voltages of between 3V and 3.6V. The parts offer a low delay of just 9ns.
The 74LVCZ161284ATTR includes a feature to ensure that any printers connected to it start properly when power is applied. One set of outputs stay high after the power is applied until an associated input also goes high. This prevents printer system errors caused by the cable's BUSY signal being set false at power on.
The chips are laid out with a 'flow-through' pin configuration so they are easy to design into PCBs. They are available in a TSSOP at a commercial temperature grade, at prices ranging from $0.78 to $0.85 in quantities of 1K.
Further information on these products is available at www.st.com/stdlogic.
The datasheets can be found on line
Or contact STMicroelectronics marketing department Lexington, Mass. (781) 861 2650