HIT HD74ALVCH162721 Datasheet
HD74ALVCH162721
3.3-V 20-bit Flip Flops with 3-state Outputs
ADE-205-184B (Z)
3rd. Edition
December 1999
Description
The HD74ALVCH162721’s twenty flip flops are edge triggered D-type flip flops with qualified clock
storage. On the positive transition of the clock (CLK) input, the device provides true data at the Q outputs,
provided that the clock enable (CLKEN) input is low. If CLKEN is high, no data is stored. A buffered
output enable (OE) input can be used to place the twenty outputs in either a normal logic state (high or low
level) or a high impedance state. In the high impedance state, the outputs neither load nor drive the bus
lines significantly. The high impedance state and increased drive provide the capability to drive bus lines
without need for interface or pullup components. The output enable (OE) input does not affect the internal
operation of the flip flops. Old data can be retained or new data can be entered while the outputs are in the
high impedance state. Active bus hold circuitry is provided to hold unused or floating data inputs at a valid
logic level. All outputs, which are designed to sink up to 12 mA, include 26 Ω resistors to reduce
overshoot and undershoot.
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 ±12 mA (@VCC = 3.0 V)
• Bus hold on data inputs eliminates the need for external pullup / pulldown resistors
• All outputs have equivalent 26 Ω series resistors, so no external resistors are required.
HD74ALVCH162721
Function Table
Inputs Output Q
OE CLKEN CLK D
L HXXQ
LL↑ HH
LL↑ LL
L L L or H X Q
HXXXZ
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.
*1
0
*1
0
2
Pin Arrangement
HD74ALVCH162721
OE
Q1
Q2
GND
Q3
Q4
V
CC
Q5
Q6
Q7
GND
Q8
Q9
Q10
Q11
Q12
Q13
GND
Q14
Q15
Q16
V
CC
Q17
Q18
GND
Q19
Q20
NC
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
CLK
1
2
3
4
5
6
7
8
9
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
32
31
30
29
D1
D2
GND
D3
D4
V
CC
D5
D6
D7
GND
D8
D9
D10
D11
D12
D13
GND
D14
D15
D16
V
CC
D17
D18
GND
D19
D20
CLKEN
(Top view)
3
HD74ALVCH162721
Absolute Maximum Ratings
Item Symbol Ratings Unit Conditions
Supply voltage V
Input voltage
Output voltage
*1
*1, 2
Input clamp current I
Output clamp current I
Continuous output current I
VCC, GND current / pin ICC or I
Maximum power dissipation
at Ta = 55°C (in still air)
*3
CC
V
I
V
O
IK
OK
O
GND
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
–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 mA
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
—–6mAV
—–8 V
= 2.3 V
CC
= 2.7 V
CC
— –12 VCC = 3.0 V
— 6 mA VCC = 2.3 V
—8 V
—12 V
= 2.7 V
CC
= 3.0 V
CC
4
Loading...