Datasheet

SN74GTLP21395
TWO 1-BIT LVTTL-TO-GTLP ADJUSTABLE-EDGE-RATE BUS TRANSCEIVERS
WITH SPLIT LVTTL PORT, FEEDBACK PATH, AND SELECTABLE POLARITY
SCES350B – JUNE 2001 – REVISED AUGUST 2001
3–54
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
description (continued)
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.
This device is fully specified for live-insertion applications using I
off
, power-up 3-state, and BIAS V
CC
. The I
off
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 V
CC
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 V
CC
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 V
CC
through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of
the driver.
terminal assignments
1234
A 1T/C 1Y 1OEBY 2T/C
B GND GND 2Y 2OEBY
C V
CC
1OEAB ERC 1B
D GND GND 1A 2B
E 2OEAB 2A BIAS V
CC
V
REF
ORDERING INFORMATION
T
A
PACKAGE
†
ORDERABLE
PART NUMBER
TOP-SIDE
MARKING
Tube SN74GTLP21395DW
SOIC – DW
Tape and reel SN74GTLP21395DWR
GTLP21395
–40°C to 85°C
TSSOP – PW Tape and reel SN74GTLP21395PWR
TVSOP – DGV Tape and reel SN74GTLP21395DGVR
VFBGA – GQN Tape and reel SN74GTLP21395GQNR
†
Package drawings, standard packing quantities, thermal data, symbolization, and PCB design
guidelines are available at www.ti.com/sc/package.
PRODUCT PREVIEW
GQN PACKAGE
(TOP VIEW)
1234
A
B
C
D
E