VFC320

9

SBVS017A

FIGURE 12. Remote Transducer Readout via Fiber Optic Link (Analog and Digital Output).

FIGURE 13. Bipolar input is accomplished by offsetting the

input to the VFC with a reference voltage.

Accurately matched resistors in the REF101

provide a stable half-scale output frequency at

zero volts input.

FIGURE 14. Absolute value circuit with the VFC320. Op

amp, D

1

and Q

1

(its base-emitter junction

functioning as a diode) provide full-wave

rectification of bipolar input voltages. VFC

output frequency is proportional to | e

sign bit output provides indication of the input

polarity.

3510B

VFC320

0.01µF

C

1

3270pF

C

2

R

3

40.2k

Ω

R

2

100k

Ω

R

1

11k

Ω

4.7k

Ω

4.7k

Ω

+V

CC

V

IN

8.66k

Ω

R

4

D

1

IN4154

2N2222

Sign Bit

Out

e

1

Bipolar

Input

Q

1

f

OUT

–

+

Integrator

Current

20k

Ω

20k

Ω

REF101

VFC320

10

13

7

5

7

+15V

8

1

+10V to –10V

Input

4

10V

30k

Ω

12

0.01µF

+15V

3

3300pF

11

14

–15V

0 to

10kHz

Output

1

Gain Adjust

6

5

2k

Ω

VFC320

V/F

V

IN

f

OUT

Clock

BCD

Counter

Driver

INA101

Transducer

Precision DC

levels down to

10mV full scale

FOT

FOR

Display

VFC320

F/V

V

OUT

f

IN

Analog

Output

Digital

Output

0.005% Linearity

Instrumentation

Amp