Analog Devices is claiming to have industry’s highest accuracy isolated ΣΔ converter for dc and ac current and voltage measurement.
The AD7403 achieves 81dBmin signal-to-noise and distortion ratio (SINAD, at 78ksample/s over -40 to 125°C).
“Higher SINAD enables more accurate current and voltage measurement which improves the performance of motor drives by reducing torque ripple on the motor shaft,” said ADI.
It has a second-order, ΣΔ modulator that converts an analogue input signal into a single-bit data stream with on-chip digital isolation (1,250Vpeak) through on-chip transformers.
Operation is from 5V at the measurement end and it accepts a differential input signal of ±250mV (±320mV full-scale).
The analogue input is continuously sampled and converted to a ones-density bit stream with a data rate of up to 20MHz. The original information can be reconstructed with appropriate digital filtering to achieve 88 dB signal to noise at 78.1ksample/s.
Power on the output (and control) side is 5V or 3V.
It comes in a 16 pin wide-body SOIC.
Applications are expected in motor drives, solar inverters, and wind inverters.
AD7403 at a glance
5-20MHz external clock
16 bits, no missing codes
Typical offset drift: 1.5μV/°C
On-board digital isolator
On-board reference
True ±320 mV input range
>25 kV/μs common-mode transient immunity
from News http://ift.tt/1mdkQqi
via Yuichun
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