Isolated, Sigma-Delta ADCs with SPI

The ADE9103/ADE9112/ADE9113are precision simultaneously sampling Σ-Δ analog-to-digital converters (ADCs) for both DC and polyphase shunt-based energy metering applications. The ADE9113 integrates safety certified signal and power galvanic isolation with three simultaneously sampling fully differential 24-bit Σ-Δ ADC channels. The ADE9112 features two fully differential Σ-Δ ADC channels for isolated applications where only a single voltage channel is required. The ADE9103 is a nonisolated, 3-channel Σ-Δ ADC for use in applications where isolation is not required, such as for neutral measurement. The ADE9103/ADE9112/ADE9113 all include a high-gain, current channel best suited for use with a shunt resistor as the current sensor. Multiple ADE9103/ADE9112/ ADE9113 devices can be synchronized to sample simultaneously and provide coherent outputs.

The current channel ADC provides an 86 dBFS signal-to-noise ratio (SNR), at a sample rate of 4 kSPS, over a 1.65 kHz signal bandwidth and a typical gain drift of 13 ppm/°C, which enables down to Class 0.2 accuracy. The voltage ADCs provide an SNR of 91 dBFS over the same sample rate and bandwidth. The high gain on the current channel (IP and IM) aids the use of lower resistance shunts for reduced losses due to heat. The low offset drift of 2 nV/°C offers the performance required for DC metering.

The ADE9103/ADE9112/ADE9113 delivers system cost savings and increased robustness. The main ADE9103/ADE9112/ADE9113 can drive clocks of up to three additional ADE9103/ADE9112/ ADE9113 with a single crystal. The bidirectional, serial port interface (SPI) supports a daisy-chain capability, allowing access to all registers while reducing the required microcontroller pin count. The 28-lead SOICWFP allows more compact layouts. Valid data transfers are ensured with bidirectional, cyclic redundancy check (CRC) and IRQ pin alerts the system of critical faults. The ADE9112 and ADE9113 pass CISPR 32 Class B emissions on a 2-layer printed circuit board (PCB) with the addition of a high voltage capacitor and on a 4-layer PCB with an internal stitching capacitor.

APPLICATIONS

* Shunt-based polyphase meters

* Electric vehicle supply equipment

* DC meters

* Power quality monitoring

* Solar inverters

* Process monitoring

* Protective devices

* Isolated sensor interfaces

* 2 (ADE9112) or 3 (ADE9113) channel isolated, simultaneously sampling Σ-Δ ADCs, with integrated isoPower, isolated dc-to-dc converters

* 3 (ADE9103) channel nonisolated, simultaneously sampling Σ-Δ ADCs

* Synchronization of multiple ADE9103/ADE9112/ADE9113 devices

* 4-wire SPI with bidirectional CRC and daisy-chain functionality

* Unique SPI readable part ID registers

* Up to 4 ADE9103/ADE9112/ADE9113 devices clocked from a single crystal or an external clock

* IRQ hardware pin and registers for fault detection and robustness

* Sample rate up to 32 kSPS

* SNR up to 95 dB

* ±31.25 mV peak analog input voltage range for current channel

* ±500 mV peak single-ended analog input voltage range for voltage channels