HIT HD74ALVCH16269 Datasheet
HD74ALVCH16269
12-bit to 24-bit Registered Bus Transceivers
with 3-state Outputs
ADE-205-136 (Z)
Preliminary 1st. Edition
May 1996
Description
The HD74ALVCH16269 is used in applications where two separate ports must be multiplexed onto, or
demultiplexed from, a single port. The device is particularly suitable as an interface between
synchronous DRAMs and high speed microprocessors. Data is stored in the internal B port registers on
the low to high transition of the clock (CLK) input when the appropriate clock enable (CLKENA)
inputs are low. Proper control of these inputs allows two sequential 12-bit words to be presented as a
24-bit word on the B port. For data transfer in the B to A direction, a single storage register is
provided. The select ( SEL) line selects 1B or 2B data for the A outputs. The register on the A output
permits the fastest possible data transfer, thus extending the period that the data is valid on the bus.
The control terminals are registered so that all transactions are synchronous with CLK. Data flow is
controlled by the active low output enables (OEA, OEB1, OEB2). Active bus hold circuitry is
provided to hold unused or floating data inputs at a valid logic level.
Features
• VCC = 2.3 V to 3.6 V
• Typical VOL ground bounce < 0.8 V (@VCC = 3.3 V, Ta = 25°C)
• Typical VOH undershoot > 2.0 V (@VCC = 3.3 V, Ta = 25°C)
• High output current ±24 mA (@VCC = 3.0 V)
• Bus hold on data inputs eliminates the need for external pullup / pulldown resistors
HD74ALVCH16269
Function Table
Inputs Outputs
CLK OEA OEB A 1B, 2B
↑ HHZ Z
↑ H L Z Active
↑ L H Active Z
↑ L L Active Active
Output enable
Inputs Outputs
CLKENA1 CLKENA2 CLK A 1B 2B
HHXX1B
*1
0
LX↑LL X
LX↑HH X
XL↑LX L
XL↑HX H
A-to-B storage (OEB = L)
2B0
*1
Inputs Output A
CLK SEL 1B 2B
XHXX A
XLXX A
*1
0
*1
0
↑ HLX L
↑ HHX H
↑ LXL L
↑LXH H
B-to-A storage (OEA = L)
H : High level
L : Low level
X : Immaterial
Z : High impedance
↑ : Low to high transition
Note: 1. Output level before the indicated steady state input conditions were established.
Pin Arrangement
HD74ALVCH16269
OEA
OEB1
2B3
GND
2B2
2B1
V
CC
A1
A2
A3
GND
A4
A5
A6
A7
A8
A9
GND
A10
A11
A12
V
CC
1B1
1B2
GND
1B3
NC
SEL
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
OEB2
1
2
3
4
5
6
7
8
9
56
CLKENA2
55
54
2B4
53
GND
2B5
52
51
2B6
50
V
2B7
49
2B8
48
47
2B9
46
GND
2B10
45
2B11
44
43
2B12
42
1B12
1B11
41
1B10
40
GND
39
38
1B9
1B8
37
1B7
36
35
V
34
1B6
33
1B5
32
GND
31
1B4
30
CLKENA1
29
CLK
CC
CC
(Top view)
HD74ALVCH16269
Absolute Maximum Ratings
Item Symbol Ratings Unit Conditions
Supply voltage V
Input voltage
Output voltage
*1, 2
*1, 2
Input clamp current I
Output clamp current I
Continuous output current I
Maximum power dissipation
at Ta = 55°C (in still air)
*3
CC
V
I
V
O
IK
OK
O
P
T
Storage temperature Tstg –65 to 150 °C
Notes: 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.
–0.5 to 4.6 V
–0.5 to 4.6 V Except I/O ports
–0.5 to VCC +0.5 I/O ports
–0.5 to VCC +0.5 V
–50 mA VI < 0
±50 mA VO < 0 or VO > V
±50 mA VO = 0 to V
CC
±100
1 W TSSOP
CC
Recommended Operating Conditions
Item Symbol Min Max Unit Conditions
Supply voltage V
Input voltage V
Output voltage V
High level output current I
Low level output current I
CC
I
O
OH
OL
Input transition rise or fall rate ∆t / ∆v 0 10 ns / V
Operating temperature Ta –40 85 °C
Note: Unused control inputs must be held high or low to prevent them from floating.
2.3 3.6 V
0VCCV
0VCCV
— –12 mA VCC = 2.3 V
— –12 VCC = 2.7 V
— –24 VCC = 3.0 V
—12mAV
—12 V
—24 V
= 2.3 V
CC
= 2.7 V
CC
= 3.0 V
CC
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