ADI AD630SD

The AD630 is a high precision balanced modulator/demodulator that combines a flexible commutating architecture with the accuracy and temperature stability afforded by laser wafer trimmed thin film resistors. A network of on - board applications resistors provides precision closed - loop gains of ±1 and ±2 with 0.05% accuracy (AD630B). These resistors may also be used to accurately configure multiplexer gains of 1, 2, 3, or 4. External feedback enables high gain or complex switched feedback topologies. The AD630 can be thought of as a precision op amp with two independent differential input stages and a precision comparator that is used to select the active front end. The rapid response time of this comparator coupled with the high slew rate and fast settling of the linear amplifier, minimize switching distortion. The AD630 is used in precision signal processing and instrumentation applications that require wide dynamic range. When used as a synchronous demodulator in a lock - in amplifier configuration, the AD630 can recover a small signal from 100 dB of interfering noise. Although optimized for operation up to 1kHz the circuit is useful at frequencies up to several hundred kilohertz. Other features of the AD630 include pin programmable frequency compensation; optional input bias current compensation resistors, common - mode and differential - offset voltage adjustment, and a channel status output that indicates which of the two differential inputs is active.

• Receivers signal from 100 dB noise
• 2 MHz channel bandwidth
• 45V / μs slew rate
• Low crosstalk: - 120 dB at 1 kHz - 100 dB at 10 kHz
• Pin programmable, closed - loop gains of ±1 and ±2
• 0.05% closed - loop gain accuracy and match
• 100μV channel offset voltage (AD630)
• 350kHz full power bandwidth
• Chips available

• Balanced modulation and demodulation
• Synchronous detection
• Phase detection
• Quadrature detection
• Phase sensitive detection
• Lock in amplification
• Square wave multiplication