PDS-483J

Printed in U.S.A. August, 1993

VFC320

®

Comparators

–7.5V Ref

Flip-

flop

Common

f

OUT

f

IN

One-shot

V

OUT

+V

CC

–In

+In

–V

CC

C

1

FEATURES

q HIGH LINEARITY, 12 to 14 bits

q V/F OR F/V CONVERSION

q 6-DECADE DYNAMIC RANGE

q 20ppm/

q OUTPUT TTL/CMOS COMPATIBLE

APPLICATIONS

q INEXPENSIVE A/D AND D/A CONVERTER

q DIGITAL PANEL METERS

q TWO-WIRE DIGITAL TRANSMISSION

WITH NOISE IMMUNITY

q FM MOD/DEMOD OF TRANSDUCER

SIGNALS

q PRECISION LONG TERM INTEGRATOR

q HIGH RESOLUTION OPTICAL LINK FOR

ISOLATION

q AC LINE FREQUENCY MONITOR

q MOTOR SPEED MONITOR AND CONTROL

Voltage-to-Frequency

and Frequency-to-Voltage

CONVERTER

DESCRIPTION

The VFC320 monolithic voltage-to-frequency and fre-

quency-to-voltage converter provides a simple low

cost method of converting analog signals into digital

pulses. The digital output is an open collector and the

digital pulse train repetition rate is proportional to the

amplitude of the analog input voltage. Output pulses

are compatible with TTL, and CMOS logic families.

High linearity (0.005%, max at 10kHz FS) is achieved

with relatively few external components. Two exter-

nal resistors and two external capacitors are required

to operate. Full scale frequency and input voltage are

determined by a resistor in series with –In and two

capacitors (one-shot timing and input amplifier inte-

gration). The other resistor is a non-critical open

collector pull-up (f

able in three performance/temperature grades and two

package configurations. The TO-100 versions are her-

metically sealed, and specified for the –25

°C to +85°C

and –55

°C to +125°C ranges, and the dual-in-line

units are specified from –25

°C to +85°C.

International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111 • Twx: 910-952-1111

Internet: http://www.burr-brown.com/ • FAXLine: (800) 548-6133 (US/Canada Only) • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132