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Mixed-signal microcontroller integrates differential amplifier

The line of MAXQ mixed-signal microcontrollers from Maxim Integrated Products is extended with the MAXQ7670A, a complete system-on-chip, mixed-signal microcontroller that integrates all the functions needed to accurately measure small-amplitude differential analogue input signals. The MCU pushes mixed-signal performance of the previously introduced MAXQ7670 to the 12bit level, enabling measurements in the microvolt range from various types of sensors, such as AMR (anisotropic magnetoresistive) sensors. AMR sensors are typically used for contactless sensing of linear or angular displacement in automotive or industrial applications. The MCU requires only 5x5mm of board space, and offers on-chip programmable gain control on each input channel. This avoids the need for external amplification of low-amplitude signals, resulting in cost reduction and PCB area savings.

Designed to digitize and process signals in harsh, space-constrained environments, this SoC is suitable for automotive applications such as steering, braking, and throttle-position control, as well as industrial control applications such as valve positioning and shaft rotation. The on-chip RISC CPU and embedded CAN bus controller allow real-time data processing for smart sensor networks. The MCU features eight single-ended/four differential inputs, followed by a programmable-gain differential amplifier (1x or 16x) and 125ksamples/s ADC with 12bit resolution. It digitises sensor outputs for precise real-world measurements, monitors supply-rail voltage to respond to power-failure conditions, and ntegrates a watchdog timer to ensure reliable operation. Its digital interfaces consist of a CAN 2.0B controller, SPI interface, JTAG interface, and seven general-purpose I/Os. A general-purpose timer with capture, compare, and PWM capability is also provided.

The MCU includes a 16bit RISC MAXQ microcontroller core, which allows for single-cycle data fetch and execution at 16MIPS. Additionally, the device integrates 2kbyte of SRAM for data and 64kbyte of automotive-grade flash memory. In-system programming is supported for field upgrades from a built-in 8kbyte utility ROM. The user can prevent unauthorised access to flash memory through a hardware password. The MCU is available in a space-saving, 5x5mm, 40pin TQFN package, and is fully specified over the -40 to +125°C automotive temperature range.