74ALS646 View Datasheet(PDF) - Philips Electronics
Part Name
Description
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74ALS646 Datasheet PDF : 13 Pages
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Philips Semiconductors
Product specification
Transceiver/register
74ALS646/74ALS646-1
74ALS648/74ALS648-1
74ALS646/646-1
74ALS648/648-1
Octal transceiver/register, non-inverting (3-State)
Octal transceiver/register, inverting (3-State)
FEATURES
• Combines 74ALS245 and two 74ALS374 type functions in
one chip
• Independent registers for A and B buses
• Multiplexed real-time and stored data
• Choice of non-inverting and inverting data paths
• 3-State outputs
• The -1 version sink 48mA IOL within the ±5% VCC range
DESCRIPTION
The 74ALS646/74ALS646-1 and 74ALS648/74ALS648-1
transceivers/registers consist of bus transceiver circuits with 3-State
outputs, D-type flip-flops, and control circuitry arranged for
multiplexed transmission of data directly from the input bus or the
internal registers. Data on the A or B bus will be clocked into the
registers as the appropriate clock pin goes High. Output enable
(OE) and direction (DIR) and select (SAB, SBA) pins are provided
for bus management.
The 74ALS646-1 and 74ALS648-1 will sink 48mA if the VCC is
limited to 5.0V ±0.25V.
TYPE
74ALS646/646-1
74ALS648/648-1
TYPICAL fMAX
140MHz
140MHz
TYPICAL
SUPPLY CURRENT
(TOTAL)
48mA
54mA
ORDERING INFORMATION
ORDER CODE
DESCRIPTION
COMMERCIAL RANGE
VCC = 5V ±10%,
Tamb = 0°C to +70°C
24-pin plastic DIP
74ALS646N, 74ALS646-1N,
74ALS648N, 74ALS648-1N
24-pin plastic SOL
74ALS646D, 74ALS646-1D,
74ALS648D, 74ALS648-1D
DRAWING
NUMBER
SOT222-1
SOT137-1
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS
DESCRIPTION
74ALS (U.L.)
HIGH/LOW
A0 – A7
A inputs
1.0/1.0
B0 – B7
B inputs
1.0/1.0
CPAB
A-to-B clock input
1.0/1.0
CPBA
B-to-A clock input
1.0/1.0
SAB
A-to-B select input
1.0/1.0
SBA
B-to-A select input
1.0/1.0
DIR
Data flow directional control input
1.0/1.0
OE
Output enable input
1.0/1.0
A0 – A7, B0 – B7
Data outputs
750/240
A0 – A7, B0 – B7
Data outputs (-1 version)
750/480
NOTE: One (1.0) ALS unit load is defined as: 20µA in the High state and 0.1mA in the Low state.
LOAD VALUE
HIGH/LOW
20µA/0.1mA
20µA/0.1mA
20µA/0.1mA
20µA/0.1mA
20µA/0.1mA
20µA/0.1mA
20µA/0.1mA
20µA/0.1mA
15mA/24mA
15mA/48mA
1991 Feb 08
2
853–1408 01670
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