Acquisition SoCs combine convertors with Flash MCU

The ADuC845 features two 24bit sigma-delta analogue-to-digital convertors with 10 single-ended or five fully differential channels on a single chip.

Analog Devices has expanded its range of MicroConvertor data-acquisition and processing systems that integrate precision data convertors with state-of-the-art microprocessors and Flash memory, providing the solutions that designers need for the precise measurement of wide-dynamic-range, low-frequency signals.

The new ADuC845 features two 24bit sigma-delta analogue-to-digital convertors (ADCs) with 10 single-ended or five fully differential channels on a single chip.

This superior analogue precision technology is integrated with a fast, programmable 8bit, single-cycle, 8052 Flash microcontroller (MCU) with more processing capability (up to 12MIPS) than the company's existing offerings.

This new device eliminates design complexity, while maintaining extremely low noise performance, which is critical for precision instrumentation applications.

"Customers designing precision measurement instruments are increasingly demanding multichannel low noise data acquisition systems while using less board space", said Mike Britchfield, Product Line Director for Precision Convertors, Analog Devices.

"Drawing on our deep analogue experience, we've developed analogue circuitry that integrates precision data convertors with state-of-the-art microprocessors.

As a result, Analog Devices' new MicroConvertors provide the solution these designers need for the precise measurement of wide dynamic range low-frequency signals".

The ADuC845 contains dual sigma-delta ADCs, primary and auxiliary, which are specified to 24bit resolution and embedded with a single-cycle 8052 Flash MCU.

The ADC maximum throughput rate is 1.3kHz.

The on-chip code Flash/EE memory space allows for in-circuit reprogrammability while the separate data memory space provides a nonvolatile read/write block with security enhancements.

Another key feature of the part is a patented high-frequency "chopping" scheme that is implemented on both the primary and auxiliary ADCs, resulting in excellent DC offset and offset drift specifications.

The new approach is extremely beneficial in applications where low drift, noise rejection and optimum electromagnetic interference rejection are important.

In addition to the two ADCs, the ADuC845 also contains a 10-channel input multiplexer to facilitate multiple-channel systems while maintaining the ADCs' high effective number of bits of resolution (ENOB).

The device includes a temperature sensor, a programmable gain amplifier (PGA) on the primary ADC to allow direct measurement of low-level signals, a 12bit voltage output DAC, dual PWM outputs, two current sources, a reference, an oscillator and PLL which generates the 12.58MHz clock from a 32kHz crystal and UART, SPI and I2C communications ports.

For simpler applications, a lower-cost version of the ADuC845, the ADuC847, eliminates the second ADC and the DAC, and thus does not perform simultaneous A/D conversion and control via the DAC.

The devices are ideally suited for applications that require precise measurement of wide dynamic range low-frequency signals in industrial and instrumentation applications such as intelligent sensors, temperature/pressure transducers, 4-20mA control loops, and patient monitors.

The ADuC845 and ADuC847 are sampling and will be available in October 2003.

The parts come in two packaging options: a 52-pin PQFP (plastic quad flat pack) package for traditional users and a small (8 x 8mm) 56-lead CSP (chip-scale package) for space-constrained users.

These MicroConvertors also come in three memory options that include 62, 32 and 8Kbyte Flash code space.

The ADuC845 is priced at $13.16, $14.83 and $16.68 in 1000-piece quantities for the three memory options, respectively.

The ADuC847 is priced at $9.42, $11.26, and $12.98 in 1000-piece quantities, respectively.

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