Analog Devices' ADuCM355 is an on-chip system that controls and measures electrochemical sensors and biosensors. The ADuCM355 is an ultra-low power, mixed-signal MCU based on the Arm® Cortex®-M3 processor. The device features current, voltage, and impedance measurement capability.

The ADC operates at conversion rates up to 400 kSPS with an input range of -0.9 V to +0.9 V. An input mux before the ADC allows the user to select an input channel for measurement. These input channels include three external current inputs, multiple external voltage inputs, and internal channels. The internal channels allow diagnostic measurements of the internal supply voltages, die temperature, and reference voltages.

Features

On-chip impedance measurement enables monitoring and compensation of gas sensor drift for greater accuracy over lifetime
Analog input/output:
- 16-bit, 400 kSPS ADC
- Voltage, current, and temperature measurement capability:
  - Internal and external current and voltage channels
  - Ultra-low leakage switch matrix and input mux
  - Input buffers, PGA
Voltage DACs:
- Two dual output voltage DACs:
  - Output range: 0.2 V to 2.4 V (±2.2 V potential to sensor) for 12-bit outputs
- Two bias potentiostat and TIA amps:
  - Ultra-low power: 1 µA/amp
- One high-speed 12-bit voltage DAC:
  - Output range to sensor: -607 mV to +607 mV
  - High-speed TIA for impedance measurements
  - Programmable gain amp on output
Amps, accelerators, and references:
- Two low-power, low-noise amps:
  - Suitable for potentiostat bias in electrochemical sensing
- Two low-power, low-noise TIAs:
  - Suitable for measuring sensor current output in the ±0.00005 µA to ±3,000 µA range
  - Programmable load and gain resistors
- Analog hardware accelerators:
  - Digital waveform generator (refer to the ADuCM355 hardware reference manual)
  - DFT and digital filters
- 2.5 V and 1.82 V on-chip, precision voltage references
Integration of potentiostat measurement front-end with the low-power Cortex MCU creates a total solution for gas sensors
Flexible switch matrix configuration enables use in many gas, liquid, and material sensing applications
Internal temperature sensor, ±2°C accuracy:
- Impedance measurement range: < 1 Ω to 10 MΩ and 0.016 Hz to 200,000 Hz
Voltammetry scan rate up to 2,000 steps/sec
MCU:
- 26 MHz Arm Cortex-M3 processor
- Serial wire port supports code download and debugging
- 128 kB Flash and 64 kB of SRAM
Security and safety:
- Hardware cyclic redundancy check (CRC) with programmable polynomial generator (refer to the ADuCM355 hardware reference manual)
- Read and write protection of user Flash
On-chip peripherals:
- UART, I²C, and SPI serial input/output
- Up to 17 GPIO pins:
  - External interrupt option
- General-purpose, wake-up, and watchdog timers
Power:
- 2.8 V to 3.6 V supply and active measurement range
- Power supply monitor
- Active current consumption: 30 µA/MHz for digital section
- Hibernate with bias to the external sensor: 8.5 µA
- Shutdown mode with no SRAM retention: 2 µA
Package and temperature range:
- 6 mm x 5 mm, 72-lead LGA package
- Fully specified for -40°C to +85°C ambient operation