MIC50398CN [MICREL]
Six Decade Counter / Display Decoder; 六十进制计数器/显示译码器
| 型号： | MIC50398CN |
| 厂家： | 
MICREL SEMICONDUCTOR |
| 描述： | Six Decade Counter / Display Decoder |
| 文件： | 总6页 (文件大小：74K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MIC50398/MIC50399
Six Decade Counter / Display Decoder
Not Recommended for New Designs
General Description
Features
The MIC50398/9 is an ion-implanted, P-channel MOS
six-decade synchronous up/down-counter/display driver
with storage latches. The counter can be loaded
digit-by-digit with BCD data. The counter has an
asynchronous-clear function.
•
•
•
•
•
•
•
•
Single power supply
Schmitt-Trigger on the count-input
Six decades of synchronous up/down counting
Look-ahead carry or borrow
Loadable counter
Multiplexed seven-segment outputs MIC50398N
Multiplexed BCD outputs, MIC50399N
Internal scan oscillator
Scanning is controlled by the scan oscillator input which is
self-oscillating or can be driven by an external signal. The
contents of the counter can be transferred into the 6-digit
latch which is then multiplexed from MSD to LSD in BCD or
7-segment format to the output. These devices are intended
to interface directly with the standard CMOS logic families.
Pin Connection
V
V
SS
1
2
3
4
5
6
7
8
9
28 UP/DOWN
1
2
28 UP/DOWN
SS
SET
27 CARRY
SET
27 ZERO
a
b
c
d
e
f
26 COUNT INHIBIT
25 COUNT INPUT
24 LOAD COUNTER
NC
3
26 CARRY
NC
4
25 COUNT INHIBIT
24 COUNT INPUT
23 LOAD COUNTER
A
5
D
D
D
D
D
D
V
SEGMENTS
23
22
21
20
19
18
17
B
6
6
BCD
OUTPUT
D
D
D
D
D
D
V
C
D
7
22
21
20
19
18
17
16
5
6
MIC50398CN
MIC50399CN
8
4
5
DIGIT
STROBES
g
STORE
9
3
4
DIGIT
STROBES
C
D
STORE 10
10
11
12
13
2
3
C
C
C
C
C
C
C
11
12
13
14
COUNTER
BCD
INPUTS
D
C
B
A
1
C
B
A
2
COUNTER
BCD
INPUTS
DD
1
16 SCAN
DD
15 CLEAR
CLEAR 14
15 SCAN
Segment Identification
Ordering Information
a
Part Number
MIC50398CN
MIC50399CN
Temp. Range
Package
f
b
c
0°C to 70°C
0°C to 70°C
28-pin Plastic DIP
28-pin Plastic DIP
g
d
e
8-10
August 1998
MIC50398/50399
Micrel
The carry output goes high with the leading edge of the
count input at the count of 000000 when counting up or at
999999 when counting down and goes low with the negative
going edge of the same count input. During a load counter
operation the carry output is inhibited.
Operations:
Six Decade Counter, Latch
The six decade counter is synchronously incremented or
decremented on the positive edge of the count input signal.
A Schmitt trigger on this input provides hysteresis for protec-
tion against both a noisy environment and double triggering
due to a slow rising edge at the count input.
A count frequency of 1.5 MHz can be achieved if the zero
output and carry output are not used. These outputs do not
respond at this frequency due to their output delay illustrated
on the timing diagram.
The count inhibit can be changed in coincidence with
the positive transition of the count input. Count inhibit must
remain high while the count input is high to inhibit counting.
BCD & Seven Segment Outputs
BCD or seven segment outputs are available. Digit strobes
are decoded internally by a divide by six Johnson counter.
This counter scans from MSD to LSD. By bringing the SET
input low, this counter will be forced to the MSD decade
count. During this time the segment outputs are blanked to
protect against display burn out.
The counter will increment when up/down input is high (VSS)
and will decrement when up/down input is low. The up/down
input can be changed 0.75 µs prior to the positive transition
of the count input.
The clear input is asynchronous and will reset all decades to
zero when brought high but does not affect the six digit latch
or the scan counter.
BCD outputs are valid for MSD when SET is low. Applying
VSS to SET allows normal scan to resume. Digit 6 output is
active (VSS) until the next scan clock pulse brings up digit 5
output.
As long as store input is low, data is continuously transferred
from the counter to the display. Data in the counter will be
latched and displayed when store input is high. Store can be
changed in coincidence with the positive transition of the
count input.
The segment outputs and digit strobes are blanked during
the interdigit blanking time. Typically the interdigit blanking
time is 3 to 10 microseconds when using the internal scan
oscillator.
The counter is loaded digit by digit corresponding to the digit
strobe outputs. BCD thumb wheel switches with four diodes
per decade connected between the digit strobe outputs and
the BCD inputs is one method to supply BCD data for
loading the counter decades.
BCD output data changes at the beginning of the interdigit
blanking time. Therefore the BCD output data is valid when
the positive transition of a digit output occurs. BCD outputs
are on MIC50399 only.
The load counter pulse must be at VSS 2 µs prior to the
positive transition of the digit strobe of the digit to be loaded.
The load counter pulse may be removed after the positive
transition of the digit strobe since the chip internally latches
this signal. The BCD data to be loaded must be valid through
the negative transition of the digit strobe.
Scan Oscillator
The counters have an internal scan oscillator. The
frequency of the scan oscillator is determined by an external
capacitor between VSS or VDD and scan input. The wave
form present on the scan oscillator input is triangular in the
self oscillate mode. An external oscillator may also be used
to drive the scan input.
8
Inputs, Outputs
The seven segment outputs are open drain capable of
sourcing 10mA average current per segment over one digit
cycle. Segments are on when at VSS. The Carry, Zero, BCD
and digit strobe outputs are push pull and are on when at
VSS. All inputs except Counter BCD and SCAN inputs are
high impedance CMOS compatible.
In the external drive mode the interdigit blanking time will be
the sum of the negative dwell period of the external oscillator
and the normal self oscillate blanking time. (3→10 µs). Dis-
play brightness can be controlled by the duty cycle of the
external scan oscillator.
Typically, the scan oscillator will oscillate at the following
frequencies with these nominal capacitor values from VSS to
scan input.
Two basic outputs originate from the counter: zero output,
and carry output. Each output goes high on the positive
(VSS) going edge of the count input under the following
conditions:
CIN
Min
Max
820 pF
470 pF
120 pF
1.4 kHz
2.0 kHz
7.0 kHz
4.8 kHz
6.8 kHz
20 kHz
Zero output goes high for one count period when all
decades contain zero. During a load counter operation the
zero output is inhibited. Zero output is on the MIC50399
only.
August 1998
8-11
MIC50398/50399
Micrel
Functional Diagram
LED DIS
**
*50399 Only
**50398 Only
*
BCD OUT
4
7
6
7 SEGMENT DECODER
6:1 MUX
6
SCAN COU
STORE
6 DIGIT LATCH
COUNT INHIBIT
COUNT
6 DIGIT BCD
UP/DOWN COUNTER
UP/DOWN
CLEAR
8-12
August 1998
MIC50398/50399
Micrel
Absolute Maximum Ratings*
Voltage on Any Terminal Relative to VSS
Operating Temperature Range (Ambient)
+0.3V to –20V
0°C to +70°C
Storage Temperature Range (Ambient) –40°C to +100°C
*Operating above absolute maximum ratings may damage the
device.
Maximum Operating Conditions
Symbol
Parameter
Min
Max
Units
Notes
TA
Operating Temperature
0
70
°C
VSS
ISS
BV
Supply voltage (VDD = 0V)
Supply Current
10
15
40
V
mA
V
1
Break Down Voltage
VSS – 26
MIC50398 only
(Segment only @ 10 µA)
PD
Power Dissipation
670
mW
2
Electrical Characteristics
(VDD = 0V, VSS = +10.0V to +15.0, 0°C ≤ TA ≤ 70°C)
Static Operating Conditions
Symbol
VIL
Parameter
Input Low Voltage, “0”
Min
VDD
Max
0.2 VSS
VSS
Units
Notes
V
V
V
V
VIH
Input High Voltage, “1”
VSS – 1
3
4
4
VOL
Output Voltage “0” @ 30 µA
Output Voltage “1” @ 1.5 mA
0.2 VSS
VOH
IOH
0.8 VSS
8
Output Current “1”
Digit strobes
3.0
10.0
mA
mA
5
6
Segment outputs
ISCAN
ISCAN
ISET
Scan Input Pullup Current @ 0 V
Scan Input Pulldown Current @ 15 V
SET Input Pullup Current @ 0V
5.5
40
60
mA
µA
µA
2
5
Note 1: ISS with inputs and outputs open at 0°C. 33 mA at 25°C and 28 mA at 70°C. This does not include segment current.
Total power per segment must be limited not to exceed power dissipation of package. (θJA = 100°C/Watt)
Note 2: All outputs loaded.
Note 3: MIN VIH from CA CB CC CD inputs is VSS – 3.5 V. Those inputs have internal pulldown resistors to VDD
.
Note 4: This applied to the push pull CMOS compatible outputs. Does not include digit strobes on segment outputs.
Note 5: For VOUT = VSS – 2.0 Volts. Average value over one digit cycle.
Note 6: For VOUT = VSS – 3.0 Volts. Average value over one digit cycle.
August 1998
8-13
MIC50398/50399
Micrel
Timing
COUNT
tUDS
tUDS
UP/DOWN
COUNT INHIBIT
STORE
tCIS
tCIS
tSS
tSPW
tPCW
CLEAR
tCS
COUNT
ZERO
t OA
t CA
t OH
t CH
CARRY
SCAN
t L
LOAD COUNTER
Loading Counter, Register (1 Digit)
tLS
LOAD COUNTER
tLS 2.0 µs min NOTE: REF. TO POSITIVE
tDV
TRANSITION OF DIGIT OUTPUT
BCD DATA INPUT
DIGIT OUTPUT 6
tDV 2.0 µS min NOTE: REF. TO NEGATIVE
EDGE OF DIGIT OUTPUT
DIGIT OUTPUT 5 ETC
COUNT INPUT, CARRY
ZERO OUTPUT INHIBITED
DURING THIS TIME
NOTE:
The inhibit function of the zero or carry outputs does
not end when the Load Counter input goes to a “0”
unless that transition occurs during interdigit
blanking period at least 2.0 µs prior to a positive
transition of a digit output.
COUNT INPUT
tOA
tOH
ZERO OUTPUT
tCA
tCH
CARRY OUTPUT
8-14
August 1998
MIC50398/50399
Micrel
Dynamic Operating Conditions
Symbol
fCI
Parameter
Count Input Frequency
Scan Input Frequency
Count Pulse Width
Store Pulse Width
Store Setup Time
Count Inhibit Setup Time
Up/Down setup Time
Clear Pulse Width
Clear Setup Time
Zero Access Time
Zero Hold Time
Min
0
Max
1.5
20
Units
MHz
kHz
ns
Notes
7,8
fSI
0
tCPW
tSPW
tSS
325
2.0
0
9
µs
µs
10
10
10
10
10
tCIS
tUDS
tCPW
tCS
0
µs
–0.75
2.0
–0.5
µs
µs
µs
tOA
3.0
1.5
1.5
0.9
µs
10 MIC50399 only
tOH
µs
10 MIC50399 only
tCA
Carry Access Time
Carry Hold Time
µs
10
11
12
tCH
µs
tL
Load Time
1/6 fSI
Note 7: Measured at 50% duty cycle.
Note 8: If carry or zero outputs are used, the count frequency will be limited by their respective output times.
Note 9: The count pulse width must be greater than the carry access time when using the carry output.
Note 10: The positive edge of the count input is the t = 0 reference.
Note 11: Measured from negative edge of count input.
Note 12: Time to load one digit.
8
August 1998
8-15
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