5v analogue front ends with ΣΔ ADCs and sensor interfacing

Nisshinbo NA220x analogue front end app

  • NA2202 has 16bit resolution
  • NA2203 has 20bit resolution
  • NA2204 has 24bit resolution

“Microcontrollers with 5V operating voltage are still widely used in the industrial equipment market, according to the company. “In order to transmit sensor information as accurately as possible, analogue front-ends must operate at the same voltage as the microcontroller.”

Nisshinbo NA220x analogue front end block

In each case, the programmable amplifier can be set at gains from 1x to 128x and the current sources can be set to 0.1, 0.25. 0.5 or 1mA for resistance-based temperature detectors.

There are eight inputs, configurable as all single-ended or four differential pairs.

Analogue input range is almost all the way to both supplies, but varies depending on several factors – read the data sheet carefully.

The 2.048V internal reference voltage can be replaced with an external reference across two of the package pads.

Data is extracted and control commands sent in over an SPI bus.

Consumption is around 3mA, which can be reduced by three-quarters by entering the quarter-speed low-power mode.

Below this are a 140μA sleep mode (bias and regulator remain on) and a <1μA all-off ‘stand-by’ mode.

Packaging is 4 x 4 x 0.75mm.

NA220x series
SupplyAnalogue: +2.7 to +5.5V
or ±2.5V
Digital: +2.7 to +5.5V
2.9mA (normal mode)
0.9mA (low-Power)
Digital: 0.3mA
Inputsfour differential
eight single-ended
ΔΣADCNA2202 16bit
NA2203 20bit
NA2204 24bit
3.125 to 9,600sample/s
Programmable amplifier1 to 128V/V
Built-in reference2.048V ±20 mV
GPIO4 channels (shared pads)
Sensor excitationDual 0.1, 0.25, 0.5, or 1mA
CalibrationOffset Voltage and gain
InterfaceSPI (with CSB)
Error checksumCRC8
Operating range-40 to +125°C

Find the analogue front end IC product page here, and the data sheet here


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