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參數(shù)資料
| 型號： | VFC101 |
| 英文描述： | Synchronized VOLTAGE-TO-FREQUENCY CONVERTER |
| 中文描述： | 同步電壓頻率轉(zhuǎn)換器 |
| 文件頁數(shù)： | 7/10頁 |
| 文件大?。?/td> | 136K |
| 代理商： | VFC101 |
7
VFC101
tance on the output line. The rising edge of an output pulse
is determined by the RC time constant of the pull-up resistor
and the stray capacitance.
The synchronized nature of the VFC101 makes viewing its
output on an oscilloscope somewhat tricky. Since all output
pulses align with the clock, it is best to trigger and view the
clock on one of the input channels and the output can then
be viewed on another oscilloscope channel. Depending on
the VFC input voltage, the output waveform may appear as
if the oscilloscope is not properly triggered. The output
might best be visualized by imagining a constant output
frequency which is locked to a submultiple of the clock
frequency with occasional extra pulses or missing pulses to
create the necessary average frequency. It is these extra or
missing pulses that make the output waveform appear as if
the oscilloscope is not properly triggered. This behavior
amounts to a frequency or phase jitter in the output, making
frequency detection with most phase-locked loop circuitry
impractical. For the same reason, fast period measurement
(ratiometric counting) will not provide a stable reading. The
output frequency must be measured (averaged) for N counts
of f
CLOCK
to achieve a stable N counts of resolution.
SHORTENED OUTPUT PULSES
With pin 12 connected to +V
, the negative output pulse
duration is equal to one period of the clock input. Shorter
output pulses may be useful in driving optical couplers or
transformers for voltage isolation or noise rejection. This
can be accomplished by connecting capacitor C
as shown
in Figure 4. Output pulses cannot be made to exceed one
clock period in duration. Thus, a C
value which would
create an output pulse which is longer than one period of the
clock will have the same effect as disabling the one-shot,
causing the output pulse to last one clock period. The
minimum practical pulse width of the one-shot circuit is
approximately 100ns. Using C
to generate shorter output
pulses does not affect the output frequency or the gain
equation.
REFERENCE VOLTAGE
Low gain drift is achieved with a precision internal 5V
reference. This reference is brought to an external pin and
can be used for a variety of purposes. It is used to offset the
noninverting comparator input in voltage-to-frequency mode
(although a precise voltage is not required for this function).
It is very useful in many other applications such as offsetting
the input to accept bipolar input signals. It can source up to
10mA and sink 100
μ
A. Heavy loading of the reference will
change the gain of the VFC. A 10mA load interacting with
a 0.5
typical output impedance will change the VFC gain
equation and reference voltage by 0.1%.
LINEARITY PERFORMANCE
The linearity of the VFC100 is specified as the worst-case
deviation from a straight line defined by low scale and high
scale end point measurements. This worst-case deviation is
expressed as a percentage of the 10V full-scale input. All
units are tested.
Linearity performance and gain error change with full-scale
operating frequency as shown in the typical performance
curves. Integrator voltage swing (determined by C
) has a
minor effect on linearity. A small integrator voltage swing
typically leads to best linearity performance.
The best linearity performance at high full-scale frequencies
(above 500kHz) is obtained by using short output pulses
FIGURE 4. Circuit and Timing Diagram for Shortened Output Pulses.
Output
One-Shot
2
+V
CC
14
15
12
11
0.1μF
+V
CC
–V
CC
C
OS
Clock
f
OUT
Output Pulse Width With
Pin 12 Connected to +V
CC
.
t
O
f
OUT
Digital
Common
10pF
1μF
0.1μF
0.01μF
1000pF
100pF
100ns
1μs
10μs
100μs
1ms
10ms
O
O
Nominal Output Pulse Width, t
O
t
O
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| VFC101JN | Synchronized VOLTAGE-TO-FREQUENCY CONVERTER |
| VFC101KN | Synchronized VOLTAGE-TO-FREQUENCY CONVERTER |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| VFC101JN | 制造商:BB 制造商全稱:BB 功能描述:Synchronized VOLTAGE-TO-FREQUENCY CONVERTER |
| VFC101KN | 制造商:BB 制造商全稱:BB 功能描述:Synchronized VOLTAGE-TO-FREQUENCY CONVERTER |
| VFC110 | 制造商:BB 制造商全稱:BB 功能描述:High-Frequency VOLTAGE-TO-FREQUENCY CONVERTER |
| VFC-1106 | 制造商:Quest Technology International Inc 功能描述: |
| VFC110AG | 功能描述:電壓頻率轉(zhuǎn)換及頻率電壓轉(zhuǎn)換 Hi f V to f RoHS:否 制造商:Texas Instruments 全標(biāo)度頻率:4000 KHz 線性誤差:+/- 1 % FSR 電源電壓-最大: 電源電壓-最小: 最大工作溫度:+ 85 C 最小工作溫度:- 25 C 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-14 封裝:Tube |
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