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參數(shù)資料
| 型號： | ICM7216B |
| 廠商： | Intersil Corporation |
| 元件分類： | 通用總線功能 |
| 英文描述： | 8-Digit, Multi-Function, Frequency Counters/Timers |
| 中文描述： | 8位數(shù)字，多功能，頻率計數(shù)器/定時器 |
| 文件頁數(shù)： | 11/18頁 |
| 文件大?。?/td> | 642K |
| 代理商： | ICM7216B |
11
Following the priming procedure (when in single event or 1
cycle range) the device is ready to measure one (only)
event.
When timing repetitive signals, it is not necessary to “prime”
the lCM7216B as the first alternating signal states
automatically prime the device. See Figure 1.
During any time interval measurement cycle, the lCM7216B
require 200ms following B going low to update all internal
logic. A new measurement cycle will not take place until
completion of this internal update time.
Oscillator Considerations
The oscillator is a high gain CMOS inverter. An external
resistor of 10M
to 22M
should be connected between the
OSCillator INPUT and OUTPUT to provide biasing. The
oscillator is designed to work with a parallel resonant 10MHz
quartz crystal with a static capacitance of 22pF and a series
resistance of less than 35
.
For a specific crystal and load capacitance, the required gM
can be calculated as follows:
CO = Crystal Static Capacitance
RS = Crystal Series Resistance
CIN = Input Capacitance
COUT = Output Capacitance
ω
= 2
π
f
The required gM should not exceed 50% of the gM specified
for the lCM7216 to insure reliable startup. The OSCillator
INPUT and OUTPUT pins each contribute about 5pF to CIN
and COUT. For maximum stability of frequency, CIN and
COUT should be approximately twice the specified crystal
static capacitance.
In cases where non decade prescalers are used it may be
desirable to use a crystal which is neither 10MHz or 1MHz.
In that case both the multiplex rate and time between
measurements will be different. The multiplex rate is
for 10MHz mode and
for
the 1MHz mode. The time between measurements is
in the 10MHz mode and
in the 1MHz mode.
The crystal and oscillator components should be located as
close to the chip as practical to minimize pickup from other
signals. Coupling from the EXTERNAL OSClLLATOR INPUT
to the OSClLLATOR OUTPUT or INPUT can cause
undesirable shifts in oscillator frequency.
Display Considerations
The display is multiplexed at a 500Hz rate with a digit time of
244
μ
s. An interdigit blanking time of 6
μ
s is used to prevent
display ghosting (faint display of data from previous digit
superimposed on the next digit). Leading zero blanking is
provided, which blanks the left hand zeroes after decimal
point or any non zero digits. Digits to the right of the decimal
point are always displayed. The leading zero blanking will be
disabled when the Main Counter overflows.
The lCM7216B and lCM7216D are designed to drive
common cathode displays at peak current of 15mA/segment
using displays with VF = 1.8V at 15mA. Resistors can be
added in series with the segment drivers to limit the display
current in very efficient displays, if required. The
Typical
Performance Curves
show the digit and segment currents as
a function of output voltage.
To get additional brightness out of the displays, VDD may be
increased up to 6.0V. However, care should be taken to see
that maximum power and current ratings are not exceeded.
The segment and digit outputs in lCM7216s are not directly
compatible with either TTL or CMOS logic when driving
LEDs. Therefore, level shifting with discrete transistors may
be required to use these outputs as logic signals.
Accuracy
In a Universal Counter crystal drift and quantization effects
cause errors. In
frequency, period
and
time interval
modes, a signal derived from the oscillator is used in either
the Reference Counter or Main Counter. Therefore, in
these modes an error in the oscillator frequency will cause
an identical error in the measurement. For instance, an
oscillator temperature coefficient of
measurement error of
20
will cause a
SIGNAL A
SIGNAL B
INPUT A
INPUT B
V
DD
N.O.
100K
1N914
V
DD
150K
1
0.1
μ
F
10K
10nF
1
1
1
2
2
V
SS
V
SS
V
SS
PRIME
FIGURE 10. PRIMING CIRCUIT, SIGNALS A AND B BOTH
HIGH OR LOW
DEVICE
TYPE
1
CD4049B Inverting Buffer
2
CD4070B Exclusive - OR
g
M
ω
2
C
IN
C
OUT
R
S
1
C
O
L
--------
+
2
=
where C
L
C
C
OUT
C
OUT
=
IN
------------+
f
MUX
f
10
4
×
2
------------------
=
f
MUX
f
10
3
×
2
------------------
=
------------------
6
OSC
------------------
5
OSC
20
C
------------------
C
------------------
ICM7216B
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ICM7216B_04 | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:8-Digit, Multi-Function, Frequency Counters/Timers |
| ICM7216BIJI | 制造商:HAR 功能描述:7216 HAR'86 13/TUBE CERAMIC |
| ICM7216BIPI | 制造商:Rochester Electronics LLC 功能描述:DISPLAY 8 DIGIT FREQ COUNTER 28PDIP IND - Bulk 制造商:Intersil Corporation 功能描述: |
| ICM7216BIPI WAF | 制造商:Intersil Corporation 功能描述: |
| ICM7216BLPL | 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:8-Digit, Multi-Function, Frequency Counters/Timers |
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