Renesas ups 24bit ADC performance in 32bit MCU

Implemented in RX23E-B MCUs, the 24bit ΔΣ ADC, depending on configuration, can now convert at up to 125ksample/s – eight times faster than existing RX23E-A MCUs – or achieve a third of the noise – to 0.18µVrms at 1ksample/s. 24bit effective resolution can be achieved at 3.8sample/s.

To go with this, there is a front-end multiplexer with up to eight differential inputs, a programmable amplifier with gains between x1 and x128, and two channels of current output can be varied between 50µA and 1mA to energise sensors.

“RX23E-B facilitates faster and more precise measurements of critical strain, temperature, pressure, flow rate, current and voltage, making it ideal for high-end sensors, measuring instruments and test equipment. In particular [to measure] force sensors used in industrial robots which often demand 100,000sample/s,” according to the company. “The ±10V analog input enables ±10V measurement with a 5V power supply without requiring external components.”

Some variants have a slower (31.25ksample/s) 24bit ΔΣ ADC, and some lack the ±10V inputs. Variants are also available with or without a segment-type LCD driver.

The -B series does lose out to the -A series in that it is only available with one 24bit ΔΣ ADC, while the -A series had the option of two in some packages.

However, the -B series has a 16bit DAC (DNL = ±1LSB, INL = ±5LSB with 4.5Vref) that was not available in the earlier parts.

Both series also have a 1.4µs 12bit successive approximation ADC, and a 32MHz RXv2 processing core with DSP instructions and a floating point unit (FPU).

All package options are square, starting with a 5.5mm 100pad BGA and a 6mm 40pad QFN, and finishing with LFQFPs at 7mm (48pad), 10mm (64pad), 12mm (80pad) and 14mm (100pad).

In robotics, applications are particularly foreseen where distributed architectures demand local processing.

Find the RX23E-B product page here – note, the data sheet is augmented by a large user’s hardware manual.