MM74C928N [TI]
CMOS SERIES, ASYN NEGATIVE EDGE TRIGGERED 16-BIT UP DISPLAY DRIVER COUNTER, PDIP18, PLASTIC, DIP-18;
| 型号： | MM74C928N |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | CMOS SERIES, ASYN NEGATIVE EDGE TRIGGERED 16-BIT UP DISPLAY DRIVER COUNTER, PDIP18, PLASTIC, DIP-18 驱动 光电二极管 逻辑集成电路 触发器 |
| 文件： | 总8页 (文件大小：209K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
March 1988
MM74C925, MM74C926, MM74C927, MM74C928
4-Digit Counters with Multiplexed
7-Segment Output Drivers
General Description
These CMOS counters consist of a 4-digit counter, an inter-
nal output latch, NPN output sourcing drivers for a 7-seg-
ment display, and an internal multiplexing circuitry with four
multiplexing outputs. The multiplexing circuit has its own
free-running oscillator, and requires no external clock. The
counters advance on negative edge of clock. A high signal
on the Reset input will reset the counter to zero, and reset
the carry-out low. A low signal on the Latch Enable input will
latch the number in the counters into the internal output
latches. A high signal on Display Select input will select the
number in the counter to be displayed; a low level signal on
the Display Select will select the number in the output latch
to be displayed.
an overflow indicator which is high at 2000, and it goes back
low only when the counter is reset. Thus, this is a 3(/2-digit
counter.
Features
Y
Wide supply voltage range
Guaranteed noise margin
High noise immunity
3V to 6V
1V
Y
Y
Y
0.45 V
(typ.)
40 mA
CC
High segment sourcing current
@
b
e
5V
V
CC
1.6V, V
CC
Y
Internal multiplexing circuitry
Design Considerations
The MM74C925 is a 4-decade counter and has Latch En-
able, Clock and Reset inputs.
Segment resistors are desirable to minimize power dissipa-
tion and chip heating. The DS75492 serves as a good digit
driver when it is desired to drive bright displays. When using
this driver with a 5V supply at room temperature, the display
can be driven without segment resistors to full illumination.
The user must use caution in this mode however, to prevent
overheating of the device by using too high a supply voltage
or by operating at high ambient temperatures.
The MM74C926 is like the MM74C925 except that it has a
display select and a carry-out used for cascading counters.
The carry-out signal goes high at 6000, goes back low at
0000.
The MM74C927 is like the MM74C926 except the second
most significant digit divides by 6 rather than 10. Thus, if the
clock input frequency is 10 Hz, the display would read
tenths of seconds and minutes (i.e., 9:59.9).
The input protection circuitry consists of a series resistor,
and a diode to ground. Thus input signals exceeding V
CC
The MM74C928 is like the MM74C926 except the most sig-
nificant digit divides by 2 rather than 10 and the carry-out is
will not be clamped. This input signal should not be allowed
to exceed 15V.
Connection Diagrams
Dual-In-Line Package
Dual-In-Line Package
TL/F/5919–2
TL/F/5919–1
Top View
Top View
Order Number MM74C926,
MM74C927 or MM74C928
Order Number MM74C925
C
1995 National Semiconductor Corporation
TL/F/5919
RRD-B30M105/Printed in U. S. A.
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.
b a
65 C to 150 C
Storage Temperature Range
Power Dissipation (P )
§
D(MAX)
§
vs T Graph
Refer to P
D
A
Operating V Range
CC
3V to 6V
6.5V
b
a
0.3V
Voltage at Any Output Pin
Voltage at Any Input Pin
Operating Temperature
GND 0.3V to V
CC
V
CC
b
a
GND 0.3V to 15V
Lead Temperature
(Soldering, 10 seconds)
260 C
§
b
a
40 C to 85 C
§
Range (T )
A
§
s
s
a
b
DC Electrical Characteristics Min/Max limits apply at 40 C
T
j
85 C, unless otherwise noted
§
§
Symbol
Parameter
Conditions
Min
Typ
Max Units
CMOS TO CMOS
e
e
e
V
V
V
Logical ‘‘1’’ Input Voltage
Logical ‘‘0’’ Input Voltage
V
CC
V
CC
V
CC
5V
3.5
V
IN(1)
5V
1.5
V
IN(0)
e b
10 mA
Logical ‘‘1’’ Output Voltage
(Carry-Out and Digit Output
Only)
5V, I
OUT(1)
O
4.5
V
e
e
e
10 mA
V
Logical ‘‘0’’ Output Voltage
Logical ‘‘1’’ Input Current
Logical ‘‘0’’ Input Current
Supply Current
V
V
V
5V, I
0.5
1
V
OUT(0)
CC
CC
CC
O
e
I
I
I
5V, V
5V, V
15V
0V
0.005
mA
mA
IN(1)
IN
IN
e
e
e
b
b
1
0.005
20
IN(0)
CC
V
V
5V, Outputs Open Circuit,
0V or 5V
CC
1000
0.8
mA
e
IN
CMOS/LPTTL INTERFACE
e
e
e
b
V
V
V
Logical ‘‘1’’ Input Voltage
Logical ‘‘0’’ Input Voltage
V
CC
V
CC
V
CC
4.75V
4.75V
4.75V,
V
CC
2
V
V
IN(1)
IN(0)
Logical ‘‘1’’ Output Voltage
(Carry-Out and Digit
Output Only)
OUT(1)
e b
I
O
360 mA
2.4
V
V
e
e
4.75V, I
O
V
Logical ‘‘0’’ Output Voltage
V
CC
360 mA
0.4
OUT(0)
OUTPUT DRIVE
Output Voltage (Segment
e b
e b
e
e
e
T
j
b
b
1.6
b
2
b
b
b
V
OUT
I
65 mA, V
40 mA, V
5V, T
25 C
V
2
V
V
V
1.3
1.2
1.4
V
V
V
§
100 C
OUT
OUT
CC
j
CC
CC
CC
CC
e
e
Sourcing Output)
V
§
CC
I
5V
CC
Ð
T
j
150 C
V
§
CC
e b
e b
e
e
e
T
j
R
Output Resistance (Segment
Sourcing Output)
I
I
65 mA, V
40 mA, V
5V, T
25 C
20
30
35
32
40
50
X
X
X
§
100 C
ON
OUT
CC
j
e
e
§
§
5V
OUT
CC
Ð
T
j
150 C
Output Resistance (Segment
0.6
0.8 %/ C
§
Output) Temperature Coefficient
e
e
e
e
e
I
Output Source Current
(Digit Output)
V
V
V
4.75V, V
1.75V, T
150 C
§
SOURCE
SOURCE
SINK
CC
CC
CC
OUT
j
b
b
2
1
mA
mA
mA
e
e
j
I
I
Output Source Current
(Carry-Out)
5V, V
0V, T
25 C
§
OUT
b
b
3.3
1.75
e
e
Output Sink Current
(All Outputs)
5V, V
V
, T
CC
25 C
§
OUT
j
1.75
3.6
i
Thermal Resistance
MM74C925
(Note 4)
75
70
100
90
C/W
C/W
§
§
jA
MM74C926, MM74C927, MM74C928
Note 1: ‘‘Absolute Maximum Ratings’’ are those values beyond which the safety of the device cannot be guaranteed. Except for ‘‘Operating Temperature Range’’
they are not meant to imply that the devices should be operated at these limits. The table of ‘‘Electrical Characteristics’’ provides conditions for actual device
operation.
Note 2: Capacitance is guaranteed by periodic testing.
Note 3: C determines the no load AC power consumption of any CMOS device. For complete explanation see 54C/74C Family Characteristics application note,
PD
AN-90.
Note 4: i measured in free-air with device soldered into printed circuit board.
jA
2
e
e
50 pF, unless otherwise noted
AC Electrical Characteristics* T
25 C, C
§
A
L
Symbol
Parameter
Conditions
Min
Typ
Max
Units
e
Square Wave Clock
e
e
f
Maximum Clock Frequency
V
5V,
T
T
25 C
§
100 C
2
4
3
MHz
MHz
MAX
CC
j
1.5
§
j
e
e
t , t
r
Maximum Clock Rise or Fall Time
Reset Pulse Width
V
CC
V
CC
5V
5V
15
ms
f
e
e
t
T
T
25 C
§
100 C
250
320
100
125
ns
ns
WR
j
§
j
e
e
e
e
e
e
e
t
t
t
t
f
Latch Enable Pulse Width
V
V
V
V
V
5V
5V
5V
5V
5V
T
T
25 C
§
100 C
250
320
100
125
ns
ns
WLE
CC
CC
CC
CC
CC
j
§
j
e
e
Clock to Latch Enable Set-Up Time
Latch Enable to Reset Wait Time
Reset to Latch Enable Set-Up Time
T
T
25 C
§
100 C
2500
3200
1250
1600
ns
ns
SET(CK, LE)
LR
j
§
j
e
e
b
b
T
T
25 C
§
100 C
0
0
100
100
ns
ns
j
§
j
e
e
T
T
25 C
§
100 C
320
400
160
ns
ns
SET(R, LE)
MUX
j
200
1000
5
§
j
Multiplexing Output Frequency
Input Capacitance
Hz
pF
C
Any Input (Note 2)
IN
*AC Parameters are guaranteed by DC correlated testing.
Functional Description
Reset
@
V
OUT
e
Ð Asynchronous, active high
Segment Output Ð Current sourcing with 40 mA
b
V
CC
1.6V (typ.) Also, sink capability
2 LTTL loads
Display Select Ð High, displays output of counter
Low, displays output of latch
e
@
e
2 LTTL
Digit Output
Carry-Out
Ð Current sourcing with 1 mA
1.75V. Also, sink capability
loads
V
OUT
Latch Enable
Ð High, flow through condition
Low, latch condition
e
Clock
Ð Negative edge sensitive
Ð 2 LTTL loads. See carry-out waveforms.
Typical Performance Characteristics
Typical Average Segment
Current vs Segment
Typical Segment Current
Maximum Power Dissipation
TL/F/5919–3
e
Note: V
Voltage across digit driver
D
3
Logic and Block Diagrams
MM74C925
MM74C926
MM74C927
MM74C928
TL/F/5919–4
TL/F/5919–5
TL/F/5919–6
TL/F/5919–7
4
Logic and Block Diagrams (Continued)
Segment Output Driver
Input Protection
TL/F/5919–9
TL/F/5919–8
Common Cathode LED Display
Segment Identification
TL/F/5919–10
TL/F/5919–11
Switching Time Waveforms
Input Waveforms
Multiplexing Output Waveforms
TL/F/5919–12
TL/F/5919–13
e
T
1/f
MUX
5
Switching Time Waveforms (Continued)
Carry-Out Waveforms
TL/F/5919–14
Physical Dimensions inches (millimeters)
Ceramic Dual-In-Line Package (J)
Order Number MM74C925J
NS Package Number J16A
6
Physical Dimensions inches (millimeters) (Continued)
Ceramic Dual-In-Line Package (J)
Order Number MM74C926J, MM74C927J or MM74C928J
NS Package Number J18A
Molded Dual-In-Line Package (N)
Order Number MM74C925N
NS Package Number N16E
7
Physical Dimensions inches (millimeters) (Continued)
Molded Dual-In-Line Package (N)
Order Number MM74C926N, MM74C927N or MM74C928N
NS Package Number N18A
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