Sigma-Delta Modulator Simplifies Sensor-Circuit Design

Capable of converting a differential analogue input to a serial digital output at up to 20MHz, and with optical isolation included, the ACPL-796J-xxxE from Avago Technologies can be connected directly to low-level signal sources.

The ACPL-796J-xxxE is a second-order sigma-delta modulator that over-samples the analogue input using an external clock connected across the isolation barrier. This allows synchronous operation with any digital controller. Low offset voltage, low gain error and high linearity simplify the design of sensing circuits, and the SO-16 package is smaller than conventional current transducers as well as being suitable for automatic placement. The digital interface is compatible with 3V or 5V systems, and the device offers a wide dynamic range up to 80dB at 5.0V, depending on filter selection. Further advantages include high common-mode rejection, allowing engineers to achieve smoother motor controls benefitting from the high precision, stability and reliability inherent in sigma-delta modulator technology. Worldwide safety approvals include UL1577 and EN60747-5-5.

 

FEATURES ±320mV full-scale input capability 16-bits resolution, no missing codes ≤74dB signal-to-noise ratio ≤3.5µV/°C offset drift ≤1% gain error

APPLICATIONS Motor phase- and rail-current sensing Power-inverter current and voltage sensing Industrial process control Data-acquisition systems General-purpose current and voltage sensing Traditional current transducer replacement

 

 

 

• Microchip’s dsPIC33FJ12MC, page 090302
• Freescale’s 56F8002/6, page 090303

 

Avago Technologies / ACPL-796J-000E