ADI AD654JRZ-REEL7

The AD654 is a monolithic V/F converter consisting of an input amplifier, a precision oscillator system, and a high-current output stage. A single RC network is all that is needed to set any full-scale (FS) frequency up to 500 kHz and any FS input voltage up to ±30 V. For a 250 kHz FS, linearity error is only 0.03%, and operation over an 80 dB dynamic range is guaranteed. The overall temperature coefficient (excluding the effects of external components) is typically ±50 ppm/°C. The AD654 operates from a single supply of 5 V to 36 V with a quiescent current of only 2.0 mA.

The low-drift (4 μV/°C typical) input amplifier allows direct processing of small signals from thermocouples, strain gauges, and similar sources, while providing high (250 MΩ) input resistance. Unlike most V/F converters, the AD654 provides a square wave output and can drive up to 12 TTL loads, optocouplers, long cables, or similar loads.

• Low cost
• Single or dual supply, 5 V to 36 V, ±5 V to 18 V
• Full-scale frequency up to 500 kHz
• Minimum external components required
• Versatile input amplifier
  • Positive voltage mode
  • Negative current mode
  • High input impedance, low drift
• Low power: 2.0 mA quiescent current
• Low offset: 1 mV