AMC1204 - 1-Bit, 20MHz, Second-Order, Isolated Delta-Sigma Modulator

The AMC1204 and AMC1204B are 1-bit digital output, isolated delta-sigma (ΔΣ) modulators that can be clocked at up to 20 MHz. The digital isolation of the modulator output is provided by a silicon dioxide (SiO₂) barrier that is highly resistant to magnetic interference. This barrier has been certified to provide basic galvanic isolation of up to 4000 V_PEAK (AMC1204) and 4250 V_PEAK (AMC1204B) according to UL1577, VDE V 0884-10, and CSA standards or specifications.

The AMC1204 and AMC1204B provide a single-chip solution for measuring the small signal of a shunt resistor across an isolated barrier. These types of resistors are typically used to sense currents in motor control inverters, green energy generation systems, and other industrial applications. The AMC1204 and AMC1204B differential inputs easily connect to the shunt resistor or other low-level signal sources. An internal reference eliminates the need for external components. When used with an appropriate external digital filter, an effective number of bits (ENOB) of 14 is achieved at a data rate of 78 kSPS.

A 5-V analog supply (AVDD) is used by the modulator while the isolated digital interface operates from a 3-V, 3.3-V, or 5-V supply (DVDD). The AMC1204 and AMC1204B are available in SOIC-16 (DW) and SOIC-8 (DWV) packages and are specified from –40°C to 105°C.

• ±250-mV Input Voltage Range Optimized for
  Shunt Resistors
• Certified Digital Isolation:
  • CSA, VDE V 0884-10, and UL1577 Approved
  • Isolation Voltage: 4250 V_PEAK (AMC1204B)
  • Working Voltage: 1200 V_PEAK
  • Transient Immunity: 15 kV/µs
• Long Isolation Barrier Lifetime
  (see Application Report SLLA197)
• High Electromagnetic Field Immunity
  (see Application Note SLLA181A)
• Outstanding AC Performance:
  • SNR: 84 dB (Minimum)
  • THD: –80 dB (Maximum)
• Excellent DC Precision:
  • INL: ±8LSB (Maximum)
  • Gain Error: ±2% (Maximum)
• External Clock Input for Easier Synchronization
• Fully Specified Over the Extended Industrial
  Temperature Range