FEATURES
• TI-OPC™ Circuitry Limits Ringing on
Unevenly Loaded Backplanes
• OEC™ Circuitry Improves Signal Integrity and
Reduces Electromagnetic Interference
• Bidirectional Interface Between GTLP Signal
Levels and LVTTL Logic Levels
• Split LVTTL Port Provides a Feedback Path
for Control and Diagnostics Monitoring
• LVTTL Interfaces Are 5-V Tolerant
• High-Drive GTLP Outputs (100 mA)
• LVTTL Outputs (–24 mA/24 mA)
• Variable Edge-Rate Control (ERC) Input
Selects GTLP Rise and Fall Times for Optimal
Data-Transfer Rate and Signal Integrity in
Distributed Loads
• Ioff, Power-Up 3-State, and BIAS VCC Support
Live Insertion
• Polarity Control Selects True or
Complementary Outputs
• Latch-Up Performance Exceeds 100 mA Per
JESD 78, Class II
• ESD Protection Exceeds JESD 22
– 2000-V Human-Body Model (A114-A)
– 200-V Machine Model (A115-A)
– 1000-V Charged-Device Model (C101)

DESCRIPTION/ORDERING INFORMATION
The SN74GTLP1395 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 Ω.
GTLP is the Texas Instruments derivative of the Gunning Transceiver Logic (GTL) JEDEC standard JESD 8-3.
The ac specification of the SN74GTLP1395 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, and GTLP in BTL
Applications, literature number SCEA017.
Normally, the B port operates at GTLP signal levels. The A-port and control inputs operate at LVTTL logic levels,
but are 5-V tolerant and are compatible with TTL or 5-V CMOS devices. VREF is the B-port differential input
reference voltage.
This device is fully specified for live-insertion applications using Ioff, power-up 3-state, and BIAS VCC. 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. The BIAS VCC circuitry precharges and preconditions the B-port input/output
connections, preventing disturbance of active data on the backplane during card insertion or removal, and
permits true live-insertion capability.
This GTLP device features TI-OPC circuitry, which actively limits the overshoot caused by improperly terminated
backplanes, unevenly distributed cards, or empty slots during low-to-high signal transitions. This improves signal
integrity, which allows adequate noise margin to be maintained at higher frequencies.
High-drive GTLP backplane interface devices feature adjustable edge-rate control (ERC). Changing the ERC
input voltage between low and high adjusts the B-port output rise and fall times. This allows the designer to
optimize system data-transfer rate and signal integrity to the backplane load.
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, the output-enable (OE) input 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.