CY74FCT652T_14 Datasheet, PDF (1/16 Pages) Texas Instruments – 8-BIT REGISTERED TRANSCEIVER WITH 3-STATE OUTPUTS

D Function, Pinout, and Drive Compatible
With FCT and F Logic
D Reduced V_OH (Typically = 3.3 V) Version of
Equivalent FCT Functions
D Edge-Rate Control Circuitry for
Significantly Improved Noise
Characteristics
D I_off Supports Partial-Power-Down Mode
Operation
D Matched Rise and Fall Times
D Fully Compatible With TTL Input and
Output Logic Levels
D 64-mA Output Sink Current
32-mA Output Source Current
D Independent Register for A and B Buses
D Multiplexed Real-Time and Stored Data
Transfer
D 3-State Outputs
CY74FCT652T
8-BIT REGISTERED TRANSCEIVER
WITH 3-STATE OUTPUTS
SCCS032B – SEPTEMBER 1994 – REVISED OCTOBER 2001
Q OR SO PACKAGE
(TOP VIEW)
CPAB ₁
SAB ₂
GAB 3
A₁ 4
A₂ 5
A₃ 6
A₄ 7
A₅ 8
A₆ 9
A₇ 10
A₈ 11
GND 12
24 ^V_CC
23 ^CPBA
22 SBA
21 GBA
20 B₁
19 B₂
18 B₃
17 B₄
16 B₅
15 B₆
14 B₇
13 B₈
description
The CY74FCT652T consists of bus transceiver circuits, D-type flip-flops, and control circuitry arranged for
multiplexed transmission of data directly from the input bus or from the internal storage registers. GAB and GBA
inputs control the transceiver functions. Select-control (SAB and SBA) inputs select either real-time or
stored-data transfer. The circuitry used for select control eliminates the typical decoding glitch that occurs in
a multiplexer during the transition between stored and real-time data. A low input level selects real-time data,
and a high input level selects stored data.
Data on the A or B data bus, or both, can be stored in the internal D-type flip-flops by low-to-high transitions
of the appropriate clock (CPAB or CPBA) inputs, regardless of the select or enable levels of the control pins.
When SAB and SBA are in the real-time transfer mode, it also is possible to store data without using the internal
D-type flip-flops by simultaneously enabling GAB and GBA. In this configuration, each output reinforces its
input. Thus, when all other data sources to the two sets of bus lines are at high impedance, each set of bus
lines remains at its last state.
This device is fully specified for partial-power-down applications using I_off. The I_off circuitry disables the outputs,
preventing damaging current backflow through the device when it is powered down.
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  2001, Texas Instruments Incorporated
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