Datasheet

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VFC32

International Airport Industrial Park • Mailing Address: PO Box 11400 • Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd. • Tucson, AZ 85706

Tel: (602) 746-1111 • Twx: 910-952-1111 • Cable: BBRCORP • Telex: 066-6491 • FAX: (602) 889-1510 • Immediate Product Info: (800) 548-6132

FEATURES

● OPERATION UP TO 500kHz

● EXCELLENT LINEARITY

±0.01% max at 10kHz FS

±0.05% max at 100kHz FS

● V/F OR F/V CONVERSION

● MONOTONIC

● VOLTAGE OR CURRENT INPUT

APPLICATIONS

● INTEGRATING A/D CONVERTER

● SERIAL FREQUENCY OUTPUT

● ISOLATED DATA TRANSMISSION

● FM ANALOG SIGNAL MOD/DEMOD

● MOTOR SPEED CONTROL

● TACHOMETER

DESCRIPTION

The VFC32 voltage-to-frequency converter provides

an output frequency accurately proportional to its

input voltage. The digital open-collector frequency

output is compatible with all common logic families.

Its integrating input characteristics give the VFC32

excellent noise immunity and low nonlinearity.

Full-scale output frequency is determined by an exter-

nal capacitor and resistor and can be scaled over a

wide range. The VFC32 can also be configured as a

frequency-to-voltage converter.

The VFC32 is available in 14-pin plastic DIP, SO-14

surface-mount, and metal TO-100 packages. Commer-

cial, industrial, and military temperature range models

are available.

Voltage-to-Frequency

and Frequency-to-Voltage

CONVERTER

–In

One-Shot

OUT

–V

VFC32

Common

+In

Comparator

Input

OUT

One-Shot

Capacitor

1977 Burr-Brown Corporation PDS-372G Printed in U.S.A. October, 1998

SBVS015

Summary of content (11 pages)

PAGE 1
VFC32 ® Voltage-to-Frequency and Frequency-to-Voltage CONVERTER FEATURES DESCRIPTION ● OPERATION UP TO 500kHz The VFC32 voltage-to-frequency converter provides an output frequency accurately proportional to its input voltage. The digital open-collector frequency output is compatible with all common logic families. Its integrating input characteristics give the VFC32 excellent noise immunity and low nonlinearity. ● EXCELLENT LINEARITY ±0.01% max at 10kHz FS ±0.
PAGE 2
SPECIFICATIONS At TA = +25°C and VCC = ±15V, unless otherwise noted. VFC32KP, KU PARAMETER CONDITIONS INPUT (V/F CONVERTER) FOUT = VIN/7.5 R1 C1 Voltage Range(1) Positive Input Negative Input Current Range(1) Bias Current Inverting Input Noninverting Input Offset Voltage(2) Differential Impedance Common-mode Impedance MIN TYP >0 >0 >0 INPUT (F/V CONVERTER) VOUT = 7.
PAGE 3
ELECTROSTATIC DISCHARGE SENSITIVITY ABSOLUTE MAXIMUM RATINGS Supply Voltage ................................................................................... ±22V Output Sink Current (FOUT ) ................................................................ 50mA Output Current (VOUT) ...................................................................... +20mA Input Voltage, –Input ..................................................................... ±Supply Input Voltage, +Input ...........................
PAGE 4
TYPICAL PERFORMANCE CURVES At TA = +25°C and VCC = ±15V, unless otherwise noted. LINEARITY ERROR vs OPERATING FREQUENCY LINEARITY ERROR vs FULL SCALE FREQUENCY 1 fFULL SCALE = 10kHz, 25% Duty Cycle TA = +25°C Linearity Error (Hz) Duty Cycle = 25% at Full Scale 0.01 TA = +25°C 0.001 0.5 0 –0.5 –1.
PAGE 5
APPLICATION INFORMATION approximately 2.5Vp-p integrator voltage waveform. If C2’s value is made too low, the integrator output voltage can exceed its linear output swing, resulting in a nonlinear response. Using C2 values larger than shown in Figure 2 is acceptable. Figure 1 shows the basic connection diagram for frequencyto-voltage conversion. R1 sets the input voltage range. For a 10V full-scale input, a 40kΩ input resistor is recommended.
PAGE 6
FREQUENCY-TO-VOLTAGE CONVERSION PRINCIPLES OF OPERATION Figure 4 shows the VFC32 connected as a frequency-tovoltage converter. The capacitive-coupled input network C3, R6 and R7 allow standard 5V logic levels to trigger the comparator input. The comparator triggers the one-shot on the falling edge of the frequency input pulses. Threshold voltage of the comparator is approximately –0.7V.
PAGE 7
+15V 2.5V 0V 0 to 10kHz 0V –2.5V 12kΩ 500pF fIN 5V Logic Input C2 0.1µF 2.2kΩ VO 0 to 10V R1 40kΩ +15V 13 12 10 7 10MΩ 1 +15V One-Shot 14 100kΩ –15V 11 VFC32 4 5 C1 3.3nF –15V FIGURE 4. Frequency-to-Voltage Converter Circuit. +15V +5V 0.1µF C2 2nF 13 12 10 7 1 VIN One-Shot 14 fOUT 0 to 50kHz 0V to –10V R1 40kΩ 11 VFC32 Nonlinearity may be higher than specified due to common-mode voltage on op amp input. 0.1µF 4 5 C1 650pF Pinout shown is for DIP or SOIC package.
PAGE 8
PACKAGE OPTION ADDENDUM www.ti.
PAGE 9
PACKAGE MATERIALS INFORMATION www.ti.com 14-Jul-2012 TAPE AND REEL INFORMATION *All dimensions are nominal Device VFC32KU/2K5 Package Package Pins Type Drawing SOIC D 14 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 2500 330.0 16.4 Pack Materials-Page 1 6.5 B0 (mm) K0 (mm) P1 (mm) 9.0 2.1 8.0 W Pin1 (mm) Quadrant 16.
PAGE 10
PACKAGE MATERIALS INFORMATION www.ti.com 14-Jul-2012 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) VFC32KU/2K5 SOIC D 14 2500 367.0 367.0 38.
PAGE 11
IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46C and to discontinue any product or service per JESD48B. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.