SN74GTL16622ADGGR
18位LVTTL - TO- GTL / GTL +总线收发器 18-BIT LVTTL-TO-GTL/GTL+ BUS TRANSCEIVER
The SN74GTL16622A is an 18-bit registered bus transceiver that provides LVTTL-to-GTL/GTL+ and GTL/GTL+-to-LVTTL signal-level translation. This device is partitioned as two separate 9-bit transceivers with individual clock-enable controls and contains D-type flip-flops for temporary storage of data flowing in either direction. This device provides an interface between cards operating at LVTTL logic levels and a backplane operating at GTL/GTL+ signal levels. Higher speed operation is a direct result of the reduced output swing <1 V, reduced input threshold levels, and OEC circuitry.
The user has the flexibility of using this device at either GTL VTT = 1.2 V and VREF = 0.8 V or the preferred higher noise margin GTL+ VTT = 1.5 V and VREF = 1 V signal levels. GTL+ is the Texas Instruments derivative of the Gunning Transceiver Logic GTL JEDEC standard JESD 8-3. The B port normally operates at GTL or GTL+ signal levels, while the A-port and control inputs are compatible with LVTTL logic levels and are 5-V tolerant. VREF is the reference input voltage for the B port.
Data flow in each direction is controlled by the output-enable OEAB\ and OEBA\\\\ and clock CLKAB and CLKBA inputs. The clock-enable CEAB\ and CEBA\\\\ inputs control each 9-bit transceiver independently, which makes the device more versatile. For A-to-B data flow, the device operates on the low-to-high transition of CLKAB if CEAB\ is low. When OEAB\ is low, the outputs are active. When OEAB\ is high, the outputs are in the high-impedance state. Data flow for B to A is similar to that of A to B, but uses OEBA\, CLKBA, and CEBA\\\\.
This device is fully specified for partial-power-down applications using Ioff. The Ioff circuitry disables the outputs, preventing damaging current backflow through the device when it is powered down.
Active bus-hold circuitry holds unused or undriven LVTTL inputs at a valid logic state. Use of pullup or pulldown resistors with the bus-hold circuitry is not recommended.
To ensure the high-impedance state during power up or power down, 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. View datasheet View product folder
