Datasheet

© 2007 Microchip Technology Inc. DS21483D-page 15
TC9400/9401/9402
FIGURE 6-2: F/V Single Supply F/V Converter.
6.3 Input Buffer
F
OUT
and F
OUT
/2 are not used in the F/V mode. How-
ever, these outputs may be useful for some applica-
tions, such as a buffer to feed additional circuitry. Then,
F
OUT
will follow the input frequency waveform, except
that F
OUT
will go high 3 µs after F
IN
goes high; F
OUT
/2
will be square wave with a frequency of one-half F
OUT
.
If these outputs are not used, Pins 8, 9 and 10 should be
connected to ground (see Figure 6-3 and Figure 6-4).
FIGURE 6-3: F/V Digital Outputs.
Offset
Adjust
10 kΩ
.01 µF
6.2V
IN914
33 kΩ
100 kΩ
500 kΩ
0.1 µF
100 kΩ
V+ = 10V to 15V
1
47 pF
V
OUT
Frequency
Input
TC9400
6
10 kΩ
2
11
1.0
4
14
12
3
5
GND
V
REF
OUT
I
IN
Zero
Adjust
V
REF
I
BIAS
Amp Out
V
DD
V
SS
GND
6
7
1.0 kΩ
V+
1.0 kΩ
0.01 µF
.001 µF
DET
Note: The output is referenced to Pin 6, which is at 6.2V (Vz). For frequency meter applications,
a 1 mA meter with a series scaling resistor can be placed across Pins 6 and 12.
MΩ
MΩ
0.5 ms
Min
5.0 ms
Min
Delay = 3 ms
Input
F
OUT
F
OUT
/2