Datasheet

SN74GTLP1395
TWO 1-BIT LVTTL-TO-GTLP ADJUSTABLE-EDGE-RATE BUS TRANSCEIVERS
WITH SPLIT LVTTL PORT, FEEDBACK PATH, AND SELECTABLE POLARITY
SCES349B JUNE 2001 REVISED AUGUST 2001
3–37
POST OFFICE BOX 655303 DALLAS, TEXAS 75265
D TI-OPC Circuitry Limits Ringing on
Unevenly Loaded Backplanes
D OEC Circuitry Improves Signal Integrity
and Reduces Electromagnetic Interference
D Bidirectional Interface Between GTLP
Signal Levels and LVTTL Logic Levels
D Split LVTTL Port Provides a Feedback Path
for Control and Diagnostics Monitoring
D LVTTL Interfaces Are 5-V Tolerant
D High-Drive GTLP Outputs (100 mA)
D LVTTL Outputs (24 mA/24 mA)
D Variable Edge-Rate Control (ERC) Input
Selects GTLP Rise and Fall Times for
Optimal Data-Transfer Rate and Signal
Integrity in Distributed Loads
D I
off
, Power-Up 3-State, and BIAS V
CC
Support Live Insertion
D Polarity Control Selects True or
Complementary Outputs
description
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 .
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 (V
TT
= 1.2 V and V
REF
= 0.8 V) or GTLP (V
TT
= 1.5 V
and V
REF
= 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. V
REF
is the B-port differential input
reference voltage.
PRODUCT PREVIEW
Copyright 2001, Texas Instruments Incorporated
DGV, DW, OR PW PACKAGE
(TOP VIEW)
1Y
1T/C
2Y
GND
1OEAB
V
CC
1A
GND
2A
2OEAB
1OEBY
2T/C
2OEBY
GND
1B
ERC
2B
GND
V
REF
BIAS V
CC
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
OEC and TI-OPC are trademarks of Texas Instruments.
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other
specifications are design goals. Texas Instruments reserves the right to
change or discontinue these products without notice.