MC74LCX646 Datasheet, PDF (1/10 Pages) Motorola, Inc – LOW-VOLTAGE CMOS OCTAL TRANSCEIVER/ REGISTERED TRANSCEIVER

MOTOROLA
SEMICONDUCTOR TECHNICAL DATA
Low-Voltage CMOS Octal
Transceiver/Registered
Transceiver
With 5V-Tolerant Inputs and Outputs
(3-State, Non-Inverting)
The MC74LCX646 is a high performance, non–inverting octal
transceiver/registered transceiver operating from a 2.7 to 3.6V supply.
High impedance TTL compatible inputs significantly reduce current
loading to input drivers while TTL compatible outputs offer improved
switching noise performance. A VI specification of 5.5V allows
MC74LCX646 inputs to be safely driven from 5V devices. The
MC74LCX646 is suitable for memory address driving and all TTL level
bus oriented transceiver applications.
Data on the A or B bus will be clocked into the registers as the
appropriate clock pin goes from a LOW–to–HIGH logic level. Output
Enable (OE) and DIR pins are provided to control the transceiver outputs.
In the transceiver mode, data present at the high impedance port may be
stored in either the A or the B register or in both. The select controls (SBA,
SAB) can multiplex stored and real–time (transparent mode) data. The
direction control (DIR) determines which bus will receive data when the
enable OE is active LOW. In the isolation mode (OE HIGH), A data may
be stored in the B register or B data may be stored in the A register. Only
one of the two buses, A or B, may be driven at one time.
• Designed for 2.7 to 3.6V VCC Operation
• 5V Tolerant — Interface Capability With 5V TTL Logic
• Supports Live Insertion and Withdrawal
• IOFF Specification Guarantees High Impedance When VCC = 0V
• LVTTL Compatible
• LVCMOS Compatible
• 24mA Balanced Output Sink and Source Capability
• Near Zero Static Supply Current in All Three Logic States (10µA)
Substantially Reduces System Power Requirements
• Latchup Performance Exceeds 500mA
• ESD Performance: Human Body Model >2000V; Machine Model >200V
VCC CBA SBA OE B0 B1 B2 B3 B4 B5 B6 B7
24 23 22 21 20 19 18 17 16 15 14 13
Pinout: 24–Lead Package (Top View)
MC74LCX646
LOW–VOLTAGE CMOS
OCTAL TRANSCEIVER/
REGISTERED TRANSCEIVER
24
1
24
1
24
1
DW SUFFIX
PLASTIC SOIC
CASE 751E–04
SD SUFFIX
PLASTIC SSOP
CASE 940D–03
DT SUFFIX
PLASTIC TSSOP
CASE 948H–01
PIN NAMES
Pins
Function
A0–A7
B0–B7
CAB, CBA
SAB, SBA
DIR, OE
Side A Inputs/Outputs
Side B Inputs/Outputs
Clock Pulse Inputs
Select Control Inputs
Output Enable Inputs
1 2 3 4 5 6 7 8 9 10 11 12
CAB SAB DIR A0 A1 A2 A3 A4 A5 A6 A7 GND
11/96
© Motorola, Inc. 1996
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