VFC320CM

® VFC320 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 20ppm/°C max GAIN DRIFT q OUTPUT TTL/CMOS COMPATIBLE DESCRIPTION The VFC320 monolithic voltage-to-frequency and frequency-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 external 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 integration). The other resistor is a non-critical open collector pull-up (fOUT to +VCC). The VFC320 is available in three performance/temperature grades and two package configurations. The TO-100 versions are hermetically 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. 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 +VCC –In +In VOUT fIN Comparators –7.5V Ref Flipflop fOUT One-shot –VCC C1 Common 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 © 1982 Burr-Brown Corporation PDS-483J Printed in U.S.A. August, 1993 SPECIFICATIONS At TA = +25°C and ±15VDC power supply, unless otherwise noted. VFC320BG/BM/SM PARAMETER V/F CONVERTER fOUT = VIN / 7.5 R1C1, Figure 4 INPUT TO OP AMP Voltage Range(1) Current Range(1) Bias Current Inverting Input Noninverting Input Offset Voltage(3) Offset Voltage Drift Differential Impedance Common-Mode Impedance ACCURACY Linearity Error (1) (4) (5) Fig. 4 with e2 = 0 Fig. 4 with e1 = 0 IIN = VIN /RIN >0