HD74ALVCH162260
12-bit to 24-bit Multiplexed D-type Latches with 3-state Outputs
ADE-205-177B (Z)
3rd. Edition
December 1999
Description
The HD74ALVCH162260 is a 12-bit to 24-bit multiplexed D-type latch used in applications where two
separate data paths must be multiplexed onto, or demultiplexed from, a single data path. Typical
applications include multiplexing and / or demultiplexing of address and data information in
microprocessor or bus interface applications. This device is also useful in memory interleaving
applications. Three 12-bit I / O ports (A1-A12, 1B1-1B12, and 2B1-2B12) are available for address and /
or data transfer. The output enable (OE1B,
OE2B,
and
OEA)
inputs control the bus transceiver functions.
The
OE1B
and
OE2B
control signals also allow bank control in the A-to-B direction. Address and / or data
information can be stored using the internal storage latches. The latch enable (LE1B, LE2B, LEA1B, and
LEA2B) inputs are used to control data storage. When the latch enable input is high, the latch is
transparent. When the latch enable input goes low, the data present at the inputs is latched and remains
latched until the latch enable input is returned high. Active bus hold circuitry is provided to hold unused or
floating data inputs at a valid logic level. The B outputs, which are designed to sink up to 12 mA, include
26
Ω
resistors to reduce overshoot and undershoot.
Features
•
V
CC
= 2.3 V to 3.6 V
•
Typical V
OL
ground bounce < 0.8 V (@V
CC
= 3.3 V, Ta = 25°C)
•
Typical V
OH
undershoot > 2.0 V (@V
CC
= 3.3 V, Ta = 25°C)
•
High output current
±12
mA (@V
CC
= 3.0 V)
•
Bus hold on data inputs eliminates the need for external pullup / pulldown resistors
•
B-port outputs have equivalent 26
Ω
series resistors, so no external resistors are required.
HD74ALVCH162260
Absolute Maximum Ratings
Item
Supply voltage
Input voltage
*1, 2
Symbol
V
CC
V
I
Ratings
–0.5 to 4.6
–0.5 to 4.6
–0.5 to V
CC
+0.5
Output voltage
*1, 2
Input clamp current
Output clamp current
Continuous output current
V
CC
, GND current / pin
Maximum power dissipation
at Ta = 55°C (in still air)
*3
Storage temperature
Notes:
V
O
I
IK
I
OK
I
O
I
CC
or I
GND
P
T
Tstg
–0.5 to V
CC
+0.5
–50
±50
±50
±100
1
–65 to 150
V
mA
mA
mA
mA
W
°C
TSSOP
V
I
< 0
V
O
< 0 or V
O
> V
CC
V
O
= 0 to V
CC
Unit
V
V
Except I/O ports
I/O ports
Conditions
Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage
to the device. These are stress ratings only, and functional operation of the device at these or
any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute maximum rated conditions for extended periods may affect device
reliability.
1. The input and output negative voltage ratings may be exceeded if the input and output clamp
current ratings are observed.
2. This value is limited to 4.6 V maximum.
3. The maximum package power dissipation is calculated using a junction temperature of 150°C
and a board trace length of 750 mils.
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HD74ALVCH162260
Recommended Operating Conditions
Item
Supply voltage
Input voltage
Output voltage
High level output current
Symbol
V
CC
V
I
V
O
I
OH
(A port)
Min
2.3
0
0
—
—
—
I
OH
(B port)
—
—
—
Low level output current
I
OL
(A port)
—
—
—
I
OL
(B port)
—
—
—
Input transition rise or fall rate
Operating temperature
∆t
/
∆v
Ta
0
–40
Max
3.6
V
CC
V
CC
–12
–12
–24
–6
–8
–12
12
12
24
6
8
12
10
85
ns / V
°C
mA
mA
mA
Unit
V
V
V
mA
V
CC
= 2.3 V
V
CC
= 2.7 V
V
CC
= 3.0 V
V
CC
= 2.3 V
V
CC
= 2.7 V
V
CC
= 3.0 V
V
CC
= 2.3 V
V
CC
= 2.7 V
V
CC
= 3.0 V
V
CC
= 2.3 V
V
CC
= 2.7 V
V
CC
= 3.0 V
Conditions
Note: Unused control inputs must be held high or low to prevent them from floating.
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