ADI AD650SD/883B

The AD650 V/F/V (voltage-to-frequency or frequency-to-voltage converter) provides a combination of high frequency operation and low nonlinearity previously unavailable in monolithic form. The inherent monotonicity of the V/F transfer function makes the AD650 useful as a high-resolution analog-to-digital converter. A flexible input configuration allows a wide variety of input voltage and current formats to be used, and an open-collector output with separate digital ground allows simple interfacing to either standard logic families or opto-couplers. The linearity error of the AD650 is typically 20 ppm [0.002% of full scale) and 50 ppm (0.005%) maximum at 10 kHz full scale. This corresponds to approximately 14-bit linearity in an analog-to-digital converter circuit. Higher full-scale frequencies or longer count intervals can be used for higher resolution conversions. The AD650 has a useful dynamic range of six decades allowing extremely high resolution measurements. Even at 1 MHz full scale, linearity is guaranteed less than 1000 ppm (0.1%) on the AD650KN, BD, and SD grades. In addition to analog-to-digital conversion, the AD650 can be used in isolated analog signal transmission applications, phased-locked loop circuits, and precision stepper motor speed controllers. In the F/V mode, the AD650 can be used in precision tachometer and FM demodulator circuits. The input signal range and full-scale output frequency are user-programmable with two external capacitors and one resistor. Input offset voltage can be trimmed to zero with an external potentiometer.

• V/F conversion to 1 MHz
• Reliable monolithic construction
• Very low nonlinearity 0.002% typ at 10 kHz, 0.005% typ at 100 kHz, 0.07% typ at 1 MHz
• Input offset trimmable to zero
• CMOS- or TTL-compatible
• Unipolar, bipolar, or differential V/F
• V/F or F/V conversion
• Available in surface mount
• MIL-STD-883 compliant versions available

• analog-to-digital conversion
• isolated analog signal transmission applications
• phased-locked loop circuits
• precision stepper motor speed controllers
• precision tachometer
• FM demodulator circuits