Voltage-to-Frequency and Frequency-to-Voltage Converter Data Sheet AD650 FEATURES FUNCTIONAL BLOCK DIAGRAM V/F conversion to 1 MHz AD650 Reliable monolithic construction OFFSET V 1 14 OUT NULL INPUT Very low nonlinearity OFFSET OP TRIM OFFSET AMP +IN 2 13 0.002% typ at 10 kHz NULL 0.005% typ at 100 kHz IN 3 12 +V S 0.07% typ at 1 MHz BIPOLAR S1 ANALOG Input offset trimmable to zero OFFSET 4 11 GND CURRENT 1mA V 0.6V CMOS- or TTL-compatible S DIGITAL V 5 10 S Unipolar, bipolar, or differential V/F OUT GND V S IN ONE V/F or F/V conversion FREQ ONE COMPARATOR SHOT 6 9 OUT SHOT INPUT CAPACITOR COMP Available in surface mount MIL-STD-883 compliant versions available NC 7 8 F OUTPUT NC = NO CONNECT Figure 1. PRODUCT DESCRIPTION The AD650 V/F/V (voltage-to-frequency or frequency-to-voltage The AD650JN and AD650KN are offered in plastic 14-lead DIP converter) provides a combination of high frequency operation packages. The AD650JP is available in a 20-lead plastic leaded and low nonlinearity previously unavailable in monolithic form. chip carrier (PLCC). Both plastic packaged versions of the The inherent monotonicity of the V/F transfer function makes AD650 are specified for the commercial temperature range the AD650 useful as a high-resolution analog-to-digital converter. (0C to 70C). For industrial temperature range (25C to A flexible input configuration allows a wide variety of input +85C) applications, the AD650AD and AD650BD are offered voltage and current formats to be used, and an open-collector in ceramic packages. The AD650SD is specified for the full output with separate digital ground allows simple interfacing to 55C to +125C extended temperature range. either standard logic families or opto-couplers. PRODUCT HIGHLIGHTS The linearity error of the AD650 is typically 20 ppm (0.002% of 1. Can operate at full-scale output frequencies up to 1 MHz full scale) and 50 ppm (0.005%) maximum at 10 kHz full scale. (in addition to having very high linearity). This corresponds to approximately 14-bit linearity in an analog- 2. Can be configured to accommodate bipolar, unipolar, or to-digital converter circuit. Higher full-scale frequencies or differential input voltages, or unipolar input currents. longer count intervals can be used for higher resolution conversions. The AD650 has a useful dynamic range of six 3. TTL or CMOS compatibility is achieved by using an open decades allowing extremely high resolution measurements. collector frequency output. The pull-up resistor can be Even at 1 MHz full scale, linearity is guaranteed less than connected to voltages up to 30 V. 1000 ppm (0.1%) on the AD650KN, BD, and SD grades. 4. The same components used for V/F conversion can also be In addition to analog-to-digital conversion, the AD650 can be used for F/V conversion by adding a simple logic biasing used in isolated analog signal transmission applications, network and reconfiguring the AD650. phased-locked loop circuits, and precision stepper motor speed controllers. In the F/V mode, the AD650 can be used in 5. Separate analog and digital grounds prevent ground loops precision tachometer and FM demodulator circuits. in real-world applications. The input signal range and full-scale output frequency are user- 6. Available in versions compliant with MIL-STD-883. programmable with two external capacitors and one resistor. Input offset voltage can be trimmed to zero with an external potentiometer. Rev. E Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 2013 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. Technical Support www.analog.com 00797-001AD650 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 F/V Conversion .......................................................................... 10 Functional Block Diagram .............................................................. 1 High Frequency Operation ....................................................... 10 Product Description ......................................................................... 1 Decoupling and Grounding ...................................................... 12 Product Highlights ........................................................................... 1 Temperature Coefficients .......................................................... 12 Revision History ............................................................................... 2 Nonlinearity Specification ........................................................ 13 Specifications ..................................................................................... 3 PSRR ............................................................................................. 14 Absolute Maximum Ratings ............................................................ 5 Other Circuit Considerations ................................................... 14 ESD Caution .................................................................................. 5 Applications ..................................................................................... 16 Pin Configurations and Function Descriptions ........................... 6 Differential Voltage-to-Frequency Conversion ...................... 16 Circuit Operation ............................................................................. 7 Autozero Circuit ......................................................................... 16 Unipolar Configuration ............................................................... 7 Phase-Locked Loop F/V Conversion ...................................... 17 Component Selection................................................................... 8 Outline Dimensions ....................................................................... 19 Bipolar V/F .................................................................................. 10 Ordering Guide .......................................................................... 20 Unipolar V/F, Negative Input Voltage ..................................... 10 REVISION HISTORY 3/13Rev. D to Rev. E Changes to Figure 13 ...................................................................... 11 Updated Outline Dimensions ....................................................... 19 Changes to Ordering Guide .......................................................... 19 3/06Rev. C to Rev. D Updated Format .................................................................. Universal Changes to Product Highlights ....................................................... 1 Changes to Table 1 ............................................................................ 3 Added Pin Function Descriptions Table ...................................... 6 Updated Outline Dimensions ....................................................... 18 Changes to Ordering Guide .......................................................... 19 Rev. E Page 2 of 20