AD7862BR-10

Overview

The AD7862BR-10 is a dual 12-bit successive approximation analog-to-digital converter (ADC) from Analog Devices, designed for high-speed data acquisition. It features two independent ADC cores with simultaneous sampling and conversion capabilities across four analog input channels grouped into two selectable channels. The device operates on a single +5 V supply, consuming typically 60 mW in normal mode and 50 mW in power-saving mode. It includes an internal +2.5 V reference and supports input ranges of ±10 V, ±2.5 V, or 0 V to 2.5 V depending on the suffix. Key performance metrics include a throughput rate of 250 kSPS, a conversion time of 3.6 μs, and a signal-to-noise ratio of 70 dB minimum.

Feature Summary

• Simultaneous sampling and conversion of two channels preserves relative phase information between inputs.
• Integrated track/hold amplifiers ensure accurate digitization of full-scale sine waves at maximum throughput rates.
• High-speed parallel interface facilitates direct connection to microprocessors and digital signal processors.
• Automatic power-down mode reduces power consumption significantly after each conversion cycle.

Applications

• AC motor control systems requiring precise phase monitoring
• Uninterrupted power supplies (UPS) for real-time voltage and current monitoring
• Data acquisition systems needing multi-channel simultaneous sampling
• Communications equipment utilizing high-speed signal processing

Procurement Notes

Verify the specific ordering suffix to confirm the package type and temperature range. The BR suffix indicates a 28-lead Small Outline Package (SOIC) with a commercial operating temperature range of -40°C to +85°C. Ensure the input range variant matches the application requirements, as the -10 suffix specifies the ±10 V input capability. Confirm RoHS compliance status if required by local regulations.

Selection Notes

Select the AD7862BR-10 when simultaneous channel sampling is critical for maintaining signal phase relationships. Compare against the AD7863 for applications requiring 14-bit resolution, as it is pin-compatible. Consider the AD7862-3 or AD7862-2 variants if the system operates with lower voltage signals such as ±2.5 V or unipolar 0 V to 2.5 V ranges. Evaluate the need for external versus internal reference sources based on required accuracy.

Part Context

The AD7862 belongs to Analog Devices' family of high-speed, low-power dual ADCs fabricated using LC2MOS technology. This process combines precision bipolar circuits with low-power CMOS logic. The component is part of a broader series that includes variations in resolution and input ranges, serving as a foundational solution for industrial data acquisition before being superseded by newer integrated architectures.

Replacement Considerations

The AD7863 is a 14-bit pin-compatible upgrade offering higher resolution. For applications requiring more channels, consider the AD7656 series. Verify that any replacement maintains the required simultaneous sampling capability and parallel interface compatibility.

FAQ

How does the A0 input affect data reading?

The A0 input selects the multiplexer sequence. When A0 is low, the first read accesses VA1/VB1 and the second read accesses VA2/VB2. When A0 is high, the sequence is reversed, allowing flexible access to the four analog inputs.

What is the purpose of the overvoltage protection?

Overvoltage protection allows the analog inputs to withstand voltages beyond the specified range without damage. For the AD7862-10, inputs can tolerate up to ±17 V, while the AD7862-3 tolerates ±7 V, and the AD7862-2 tolerates +7 V.

Can the internal reference be used externally?

Yes, the internal +2.5 V reference is available at the VREF pin. However, because it passes through a FET switch, it has a nominal output impedance of 3 kΩ. External buffering is recommended if driving other components.