The CA‐IS1204 device is series of precision isolated sigma‐ delta (Σ‐Δ) modulator and optimized for shunt resistor‐ based current sensing or other small signal measurement applications. The input current‐sense amplifier monitors current flow through a shunt (sense) resistor and the sigma‐delta modulator converts the analog input to a digital bit stream of 1's and 0's at a much higher frequency. The digital output stage of CA‐IS1204 provides uncoded CMOS bit‐stream output.

The analog input‐side (high‐side) and digital output‐side (low‐side) are separated by unique silicon oxide (SiO2) capacitive isolation barriers that provide up to 5kVRMS galvanic isolation per UL1577 certification, and isolator driver transfers the modulator output across this isolation barrier. In systems with different voltage domains, this isolation technical is typically used to protect the low voltage side from the high voltage side in case of any faults. These devices also feature up to 150kV/μs common mode transient immunity and enable efficient signal transmission in noisy environments.

The CA‐IS1204 device features low input voltage range (±250mV) that allows the use of small sense resistor to reduce power dissipation, a low (±2%, max) gain error ensures measurement accuracy. This device also features fail‐safe output to support high safety system design. The device is specified for operation with 5MHz to 21MHz clock input. The internal sigma‐delta modulator combined with an external digital decimation sinc3 filter can achieve 85 dB signal‐to‐noise ratio (SNR) at 78.1 Ksps.

The CA‐IS1204W is specified over the ‐40°C to +125°C operating temperature range and is available in 16‐pin SOIC wide body package.