The SN74GTLP21395 is two 1-bit, high-drive, 3-wire bus transceivers that provide LVTTL-to-GTLP and GTLP-to-LVTTL signal-level translation for applications, such as primary and secondary clocks, that require individual output-enable and true/complement controls. The device allows for transparent and inverted transparent modes of data transfer with separate LVTTL input and LVTTL output pins, which provide a feedback path for control and diagnostics monitoring. The device provides a high-speed interface between cards operating at LVTTL logic levels and a backplane operating at GTLP signal levels and is designed especially to work with the Texas Instruments 3.3-V 1394 backplane physical-layer controller. High-speed (about three times faster than standard LVTTL or TTL) backplane operation is a direct result of GTLP reduced output swing (<1 V), reduced input threshold levels, improved differential input, OEC™ circuitry, and TI-OPC™ circuitry. Improved GTLP OEC and TI-OPC circuitry minimizes bus settling time, and have been designed and tested using several backplane models. The high drive allows incident-wave switching in heavily loaded backplanes, with equivalent load impedance down to 11.

The Y outputs, which are designed to sink up to 12 mA, include equivalent 26-resistors to reduce overshoot and undershoot.

GTLP is the Texas Instruments derivative of the Gunning Transceiver Logic (GTL) JEDEC standard JESD 8-3. The ac specification of the SN74GTLP21395 is given only at the preferred higher noise margin GTLP, but the user has the flexibility of using this device at either GTL (VTT= 1.2 V and VREF= 0.8 V) or GTLP (VTT= 1.5 V and VREF= 1 V) signal levels. For information on using GTLP devices in FB+/BTL applications, refer to TI application reports,Texas Instruments GTLP Frequently Asked Questions, literature number SCEA019, andGTLP in BTL Applications, literature number SCEA017.Read more