CD74FCT2952A Datasheet, PDF (1/9 Pages) Texas Instruments – BiCMOS OCTAL BUS TRANSCEIVER AND REGISTER WITH 3-STATE OUTPUTS

CD74FCT2952A
BiCMOS OCTAL BUS TRANSCEIVER AND REGISTER
WITH 3-STATE OUTPUTS
SCBS720 – JULY 2000
D BiCMOS Technology With Low Quiescent
Power
D Buffered Inputs
D Noninverted Outputs
D Input/Output Isolation From V_CC
D Controlled Output Edge Rates
D 64-mA Output Sink Current
D Output Voltage Swing Limited to 3.7 V at
V_CC = 5 V
D SCR Latch-Up-Resistant BiCMOS Process
and Circuit Design
D Packaged in Plastic Small-Outline Package
description
M PACKAGE
(TOP VIEW)
B8 1
B7 2
B6 3
B5 4
B4 5
B3 6
B2 7
B1 8
OEAB 9
CLKAB 10
CLKENAB 11
GND 12
24 V_CC
23 A8
22 A7
21 A6
20 A5
19 A4
18 A3
17 A2
16 A1
15 OEBA
14 CLKBA
13 CLKENBA
The CD74FCT2952A is an octal transceiver and register, consisting of two 8-bit, back-to-back registers that
store data flowing in both directions between two bidirectional buses. It uses a small-geometry BiCMOS
technology. Data on the A or B bus is stored in the registers on the low-to-high transition of the clock (CLKAB
or CLKBA) input if the clock-enable (CLKENAB or CLKENBA) input is low. Taking the output-enable (OEAB or
OEBA) input low accesses the data on either port.
This device contains two 8-bit, back-to-back registers that store data flowing in both directions between two
bidirectional buses. Each register has separate clock, clock enable, and 3-state output enable signals
associated with it.
The output stage is a combination of bipolar and CMOS transistors that limits the output high level to two diode
drops below V_CC. This resultant lowering of output swing (0 V to 3.7 V) reduces power-bus ringing [a source
of electromagnetic interference (EMI)] and minimizes V_CC bounce and ground bounce and their effects during
simultaneous output switching. The output configuration also enhances switching speed and is capable of
sinking 64 mA.
To ensure the high-impedance state during power up or power down, OE 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.
The CD74FCT2952A is characterized for operation from 0°C to 70°C.
FUNCTION TABLE†
INPUTS
OUTPUT
CLKENAB CLKAB OEAB A
B
H
X
L
X
B0‡
X
H or L
L
X
B0‡
L
↑
L
L
L
L
↑
L
H
H
X
X
H
X
Z
† _{A-to-B data flow is shown; B-to-A data flow is similar,}
but uses CLKENBA, CLKBA, and OEBA.
‡ _{Level of B before the indicated steady-state input}
conditions were established
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
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Copyright © 2000, Texas Instruments Incorporated
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