AMC1305x High-Precision, Reinforced Isolated Delta-Sigma Modulators

1 Features

• Pin-compatible family optimized for shunt-resistor-based current measurements:
  • ±50-mV or ±250-mV input voltage ranges
  • CMOS or LVDS digital interface options
• Excellent DC performance supporting high-precision sensing on system level:
  • Offset error: ±50 µV or ±150 µV (max)
  • Offset drift: 1.3 µV/°C (max)
  • Gain error: ±0.3% (max)
  • Gain drift: ±40 ppm/°C (max)
• Safety-related certifications:
  • 7000-V_PK reinforced isolation per
    DIN VDE V 0884-11: 2017-01
  • 5000-V_RMS isolation for 1 minute per UL1577
  • CAN/CSA no. 5A-component acceptance service notice and IEC 62368-1 end equipment standard
• Transient immunity: 15 kV/µs (min)
• High electromagnetic field immunity
  (see application note SLLA181A)
• External 5-MHz to 20-MHz clock input for
  easier system-level synchronization
• Fully specified over the extended industrial temperature range

2 Applications

• Shunt-resistor-based current sensing in:
  • Industrial motor drives
  • Photovoltaic inverters
  • Uninterruptible power supplies
• Isolated voltage sensing

3 Description

The AMC1305 is a precision, delta-sigma (ΔΣ) modulator with the output separated from the input circuitry by a capacitive double isolation barrier that is highly resistant to magnetic interference. This barrier is certified to provide reinforced isolation of up to 7000 V_PEAK according to the DIN VDE V 0884-11, UL1577, and CSA standards. Used in conjunction with isolated power supplies, the device prevents noise currents on a high common-mode voltage line from entering the local system ground and interfering with or damaging low voltage circuitry.

The AMC1305 is optimized for direct connection to shunt resistors or other low voltage level signal sources and supports excellent dc and ac performance. Shunt resistors are typically used to sense currents in motor drives, green energy generation systems, or other industrial applications. By using an appropriate digital filter (that is, as integrated on the TMS320F2837x) to decimate the bit stream, the device can achieve 16 bits of resolution with a dynamic range of 85 dB (13.8 ENOB) at a data rate of 78 kSPS.

On the high-side, the modulator is supplied with a nominal voltage of 5 V (AVDD), whereas the isolated digital interface operates from a 3.3-V or 5-V power supply (DVDD).

The AMC1305 is available in a wide-body SOIC-16 (DW) package and is specified from –40°C to +125°C.

1. For all available packages, see the orderable addendum at the end of the datasheet.