VFC320
VFC
3
20
SBVS017A – AUGUST 2001
Voltage-to-Frequency
and Frequency-to-Voltage
CONVERTER
FEATURES
q
HIGH LINEARITY: 12 to 14 bits
±
0.005% max at 10kHz FS
±
0.03% max at 100kHz FS
±
0.1% typ at 1MHz FS
q
V/F OR F/V CONVERSION
q
6-DECADE DYNAMIC RANGE
q
GAIN DRIFT: 20ppm/
°
C max
q
OUTPUT TTL/CMOS COMPATIBLE
DESCRIPTION
The VFC320 monolithic voltage-to-frequency and frequency-to-
voltage converter provides a simple low cost method of convert-
ing analog signals into digital pulses. The digital output is an
open collector and the digital pulse train repetition rate is propor-
tional 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 external resistors and
two external capacitors are required to operate. Full scale fre-
quency and input voltage are determined by a resistor in series
with –In and two capacitors (one-shot timing and input amplifier
integration). The other resistor is a non-critical open collector
pull-up (f
OUT
to +V
CC
). The VFC320 is available in two perfor-
mance grades. The VFC320 is specified for the –25°C to +85°C,
range.
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
+V
CC
–In
+In
V
OUT
f
IN
Comparators
–7.5V Ref
Flip-
flop
f
OUT
One-shot
–V
CC
C
1
Common
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
Copyright © 1982, Texas Instruments Incorporated
www.ti.com
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