Page 1
HD74HC490
Dual 4-bit Decade Counters
Description
This circuit contains eight master-slave flip-flops and additional gating to implement two individual 4-bit
decade counters. Each decade counter has individual clock, clear and set-to-9 inputs. BCD count
sequences of any length up to divide-by-100 may be implemented with a single HD74HC490. Buffering
on each output is provided to ensure that suceptibility to collector communication is reduced significantly.
The counters have paralle outputs from each counter state so that submultiples of the input count frequency
are available for system timing signals.
Features
• High Speed Operation: tpd (Clock to QA) = 13 ns typ (CL = 50 pF)
• High Output Current: Fanout of 10 LSTTL Loads
• Wide Operating Voltage: VCC = 2 to 6 V
• Low Input Current: 1 µA max
• Low Quiescent Supply Current: ICC (static) = 4 µA max (Ta = 25°C)
Function Table
Clear/Set-To-9
Inputs Outputs
Clear Set-To-9 Q
HLLLLL
LHHLLH
L L Count
A
Q
B
Q
C
Q
D
Page 2
HD74HC490
BCD Count Sequence
Outputs
Count Q
D
Q
C
0L L L L
1L L L H
2L L H L
3L L H H
4L H L L
5L H L H
6L H H L
7L H H H
8H L L L
9H L L H
Pin Arrangement
Q
B
Q
A
1Clock
1Clear
1Q
Output
1 Set-
to-9
1Q
1QC
Outputs
1QD
GND
V
1
2
A
3
4
B
5
6
7
8
CLR
A
Q
CK
QB
QC
QD
Set-to-9
CLR
QA
CK
QB
QC
Set-to-9
QD
16
15
14
13
12
11
10
9
CC
2Clock
2Clear
A
2Q
Output
2 Setto-9
2Q
B
2QC
2QD
Outputs
(Top view)
2
Page 3
HD74HC490
DC Characteristics
Ta = –40 to
Ta = 25°C
Item Symbol V
Input voltage V
IH
(V) Min Typ Max Min Max Unit Test Conditions
CC
2.0 1.5 — — 1.5 — V
4.5 3.15 — — 3.15 —
6.0 4.2 — — 4.2 —
V
IL
2.0 — — 0.5 — 0.5 V
4.5 — — 1.35 — 1.35
6.0 — — 1.8 — 1.8
Output voltage V
OH
2.0 1.9 2.0 — 1.9 — V Vin = VIH or VILIOH = –20 µA
4.5 4.4 4.5 — 4.4 —
6.0 5.9 6.0 — 5.9 —
4.5 4.18 — — 4.13 — IOH = –4 mA
6.0 5.68 — — 5.63 — IOH = –5.2 mA
V
OL
2.0 — 0.0 0.1 — 0.1 V Vin = VIH or VILIOL = 20 µA
4.5 — 0.0 0.1 — 0.1
6.0 — 0.0 0.1 — 0.1
4.5 — — 0.26 — 0.33 IOL = 4 mA
6.0 — — 0.26 — 0.33 IOL = 5.2 mA
Input current Iin 6.0 — — ±0.1 — ±1.0 µA Vin = VCC or GND
Quiescent supply
I
CC
6.0 — — 4.0 — 40 µA Vin = VCC or GND, Iout = 0 µA
current
+85°C
3
Page 4
HD74HC490
AC Characteristics (CL = 50 pF, Input tr = tf = 6 ns)
Ta = –40 to
Ta = 25°C
Item Symbol V
Maximum clock f
max
(V) Min Typ Max Min Max Unit Test Conditions
CC
2.0 — — 4 — 3 MHz
frequency 4.5 — — 20 — 16
6.0 — — 24 — 19
Propagation delay t
time t
PLH
PHL
2.0 — — 120 — 150 ns Clock to Q
4.5 — 13 24 — 30
6.0 — — 20 — 26
t
PLH
t
PHL
2.0 — — 205 — 255 ns Clock to QB Q
4.5 — 21 41 — 51
6.0 — — 35 — 43
t
PLH
t
PHL
2.0 — — 280 — 350 ns Clock to Q
4.5 — 23 56 — 70
6.0 — — 48 — 60
t
PHL
2.0 — — 205 — 255 ns Clear to any output
4.5 — 18 41 — 51
6.0 — — 35 — 43
t
PLH
2.0 — — 205 — 255 ns Set-to-9 to QA, Q
4.5 — 13 41 — 51
6.0 — — 35 — 43
t
PHL
2.0 — — 190 — 240 ns Set-to-9 to QB, Q
4.5 — 17 38 — 48
6.0 — — 32 — 41
Pulse width t
w
2.0 80 — — 100 — ns
4.5 16 6 — 20 —
6.0 14 — — 17 —
Setup time t
su
2.0 100 — — 125 — ns
4.5 20 1 — 25 —
6.0 17 — — 21 —
Output rise/fall t
time t
TLH
THL
2.0 — — 75 — 95 ns
4.5 — 5 15 — 19
6.0 — — 13 — 16
Input capacitance Cin — — 5 10 — 10 pF
+85°C
A
C
C
D
C
4
Page 5
Cautions
1. Hitachi neither warrants nor grants licenses of any rights of Hitachi’s or any third party’s patent,
copyright, trademark, or other intellectual property rights for information contained in this document.
Hitachi bears no responsibility for problems that may arise with third party’s rights, including
intellectual property rights, in connection with use of the information contained in this document.
2. Products and product specifications may be subject to change without notice. Confirm that you have
received the latest product standards or specifications before final design, purchase or use.
3. Hitachi makes every attempt to ensure that its products are of high quality and reliability. However,
contact Hitachi’s sales office before using the product in an application that demands especially high
quality and reliability or where its failure or malfunction may directly threaten human life or cause risk
of bodily injury, such as aerospace, aeronautics, nuclear power, combustion control, transportation,
traffic, safety equipment or medical equipment for life support.
4. Design your application so that the product is used within the ranges guaranteed by Hitachi particularly
for maximum rating, operating supply voltage range, heat radiation characteristics, installation
conditions and other characteristics. Hitachi bears no responsibility for failure or damage when used
beyond the guaranteed ranges. Even within the guaranteed ranges, consider normally foreseeable
failure rates or failure modes in semiconductor devices and employ systemic measures such as failsafes, so that the equipment incorporating Hitachi product does not cause bodily injury, fire or other
consequential damage due to operation of the Hitachi product.
5. This product is not designed to be radiation resistant.
6. No one is permitted to reproduce or duplicate, in any form, the whole or part of this document without
written approval from Hitachi.
7. Contact Hitachi’s sales office for any questions regarding this document or Hitachi semiconductor
products.
Hitachi, Ltd.
Semiconductor & Integrated Circuits.
Nippon Bldg., 2-6-2, Ohte-machi, Chiyoda-ku, Tokyo 100-0004, Japan
Tel: Tokyo (03) 3270-2111 Fax: (03) 3270-5109
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Copyright ' Hitachi, Ltd., 1999. All rights reserved. Printed in Japan.
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Page 6
19.20
20.00 Max
16 9
1.3
Unit: mm
6.30
7.40 Max
81
1.11 Max
2.54 ± 0.25
0.48 ± 0.10
5.06 Max
2.54 Min
0.51 Min
Hitachi Code
JEDEC
EIAJ
Weight
7.62
+ 0.13
0.25
– 0.05
0° – 15°
(reference value)
DP-16
Conforms
Conforms
1.07 g
Page 7
16
Unit: mm
10.06
10.5 Max
9
5.5
1
0.80 Max
1.27
*0.42 ± 0.08
0.40 ± 0.06
*Dimension including the plating thickness
Base material dimension
8
0.12
0.10 ± 0.10
0.15
M
2.20 Max
7.80
0.20 ± 0.04
*0.22 ± 0.05
0.70 ± 0.20
Hitachi Code
JEDEC
EIAJ
(reference value)
Weight
+ 0.20
– 0.30
1.15
0° – 8°
FP-16DA
—
Conforms
0.24 g
Page 8
16
Unit: mm
9.9
10.3 Max
9
1
1.27
0.635 Max
*0.42 ± 0.08
0.40 ± 0.06
*Dimension including the plating thickness
Base material dimension
8
0.25
+ 0.11
– 0.04
0.14
0.15
3.95
1.75 Max
M
6.10
1.08
0.20 ± 0.03
*0.22 ± 0.03
0.60
Hitachi Code
JEDEC
EIAJ
Weight
+ 0.10
– 0.30
0° – 8°
+ 0.67
– 0.20
(reference value)
FP-16DN
Conforms
Conforms
0.15 g
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