Datasheet AD650 (Analog Devices)

Voltage-to-Frequency and Frequency-to-Voltage Converter Data Sheet AD650 FEATURES FUNCTIONAL BLOCK DIAGRAM V/F conversion to 1 MHz Reliable monolithic construction AD650 OFFSET V 1 OUT 14 Very low nonlinearity NULL INPUT OP OFFSET 0.002% typ at 10 kHz AMP TRIM OFFSET +IN 2 13 NULL 0.005% typ at 100 kHz 0.07% typ at 1 MHz –IN 3 12 +VS Input offset trimmable to zero BIPOLAR S1 ANALOG OFFSET 4 11 GND CMOS- or TTL-compatible CURRENT 1mA –V –0.6V S Unipolar, bipolar, or differential V/F DIGITAL –V 5 S OUT 10 –V GND S IN V/F or F/V conversion ONE FREQ ONE COMPARATOR SHOT 6 9 Available in surface mount OUT SHOT CAPACITOR COMP INPUT MIL-STD-883 compliant versions available NC 7 8 FOUTPUT
001
NC = NO CONNECT
00797- 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. (0°C to 70°C). For industrial temperature range (−25°C to A flexible input configuration allows a wide variety of input +85°C) applications, the AD650AD and AD650BD are offered voltage and current formats to be used, and an open-col ector in ceramic packages. The AD650SD is specified for the full output with separate digital ground allows simple interfacing to −55°C to +125°C extended temperature range. either standard logic families or opto-couplers.
PRODUCT HIGHLIGHTS
The linearity error of the AD650 is typical y 20 ppm (0.002% of 1. Can operate at ful -scale output frequencies up to 1 MHz ful scale) and 50 ppm (0.005%) maximum at 10 kHz ful scale. (in addition to having very high linearity). This corresponds to approximately 14-bit linearity in an analog- to-digital converter circuit. Higher ful -scale frequencies or 2. Can be configured to accommodate bipolar, unipolar, or longer count intervals can be used for higher resolution differential input voltages, or unipolar input currents. conversions. The AD650 has a useful dynamic range of six decades al owing extremely high resolution measurements. 3. TTL or CMOS compatibility is achieved by using an open Even at 1 MHz full scale, linearity is guaranteed less than col ector frequency output. The pull-up resistor can be 1000 ppm (0.1%) on the AD650KN, BD, and SD grades. connected to voltages up to 30 V. In addition to analog-to-digital conversion, the AD650 can be 4. The same components used for V/F conversion can also be used in isolated analog signal transmission applications, used for F/V conversion by adding a simple logic biasing phased-locked loop circuits, and precision stepper motor speed network and reconfiguring the AD650. control ers. 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.
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Document Outline Features Functional Block Diagram Product Description Product Highlights Revision History Specifications Absolute Maximum Ratings ESD Caution Pin Configurations and Function Descriptions Circuit Operation Unipolar Configuration One-Shot Timing Component Selection Bipolar V/F Unipolar V/F, Negative Input Voltage F/V Conversion High Frequency Operation Decoupling and Grounding Temperature Coefficients Nonlinearity Specification PSRR Other Circuit Considerations Applications Differential Voltage-to-Frequency Conversion Autozero Circuit Phase-Locked Loop F/V Conversion Outline Dimensions Ordering Guide