Renesas Boosts 24bit ADC Performance in 32bit MCU

Renesas Revamps High-Accuracy Analogue Front-End in RX Microcontrollers

Renesas, a leading microcontroller manufacturer, has recently introduced significant improvements to the high-accuracy analogue front-end in its 32bit RX microcontrollers. These enhancements have been implemented in the RX23E-B MCUs, offering a range of advanced features and capabilities.

The standout feature of the RX23E-B MCUs is the 24bit ΔΣ ADC (Analog-to-Digital Converter), which can now achieve conversion speeds of up to 125ksample/s. This is eight times faster than the previous RX23E-A MCUs. Additionally, the new ADC can achieve a third of the noise, reducing it to 0.18µVrms at 1ksample/s. The 24bit effective resolution can be achieved at 3.8sample/s, providing exceptional accuracy and precision.

Accompanying the improved ADC is a front-end multiplexer with up to eight differential inputs, a programmable amplifier with gains ranging from x1 to x128, and two channels of current output that can be varied between 50µA and 1mA to energize sensors. These features enable faster and more precise measurements of critical strain, temperature, pressure, flow rate, current, and voltage.

The RX23E-B MCUs are particularly well-suited for high-end sensors, measuring instruments, and test equipment. Renesas highlights their effectiveness in measuring force sensors used in industrial robots, which often require a high sampling rate of 100,000sample/s. The ±10V analog input allows for ±10V measurement with a 5V power supply, eliminating the need for external components.

While the RX23E-B series offers significant improvements, there are some variations within the product line. Some variants have a slower 24bit ΔΣ ADC with a sampling rate of 31.25ksample/s, and some lack the ±10V inputs. Additionally, variants with or without a segment-type LCD driver are available.

One drawback of the RX23E-B series is that it only offers one 24bit ΔΣ ADC, whereas the previous RX23E-A series had the option of two in certain packages. However, the RX23E-B series compensates for this by including a 16bit DAC (Digital-to-Analog Converter) with a DNL (Differential Non-Linearity) of ±1LSB and an INL (Integral Non-Linearity) of ±5LSB with a 4.5V reference voltage. This feature was not available in the earlier parts.

Both the RX23E-B and RX23E-A series feature a 32MHz RXv2 CPU with DSP (Digital Signal Processing) instructions and a floating-point unit (FPU). The package options for both series are square-shaped, starting with a 5.5mm 100-pad BGA and a 6mm 40-pad QFN, and ranging up to LFQFPs at 7mm (48-pad), 10mm (64-pad), 12mm (80-pad), and 14mm (100-pad).

In the field of robotics, the RX23E-B MCUs are expected to find applications in distributed architectures that require local processing. The improved analogue front-end and advanced features make them an ideal choice for robotics applications.

For more information about the RX23E-B MCUs, please visit the RX23E-B product page. Please note that the data sheet is accompanied by a comprehensive user's hardware manual.