GENERAL DESCRIPTION

The ADuCM362-EP is a fully integrated, 3.906 kHz, 24-bit

data acquisition (DAQ) system that incorporates dual, high

performance, multichannel Σ-Δ analog-to-digital converters

(ADCs), a 32-bit ARM Cortex™-M3 processor, and Flash/EE

memory on a single chip. The ADuCM362-EP is designed for

direct interfacing to external precision sensors in both wired and

battery-powered applications.

The ADuCM362-EP contains an on-chip 32 kHz oscillator and

an internal 16 MHz high frequency oscillator. The high frequency

oscillator is routed through a programmable clock divider from

which the operating frequency of the processor core clock is

generated. The maximum core clock speed is 16 MHz. This

clock speed is not limited by operating voltage or temperature.

The microcontroller core is a low power ARM Cortex-M3

processor, 32-bit RISC machine that offers up to 20 MIPS peak

performance. The Cortex-M3 processor incorporates a flexible,

11-channel direct memory access (DMA) controller that supports

all wired communication peripherals (both serial peripheral

interfaces (SPIs), both universal asynchronous receivers/

transmitters (UARTs), and I2C). Also integrated on chip is

256 kB of nonvolatile Flash/EE memory and 24 kB of SRAM.

The analog subsystem consists of dual ADCs, each connected to

a flexible input mux. Both ADCs can operate in fully differential

and single-ended modes. Other on-chip ADC features include

dual programmable excitation current sources, diagnostic current

sources, and a bias voltage generator of AVDD_REG/2 (900 mV)

to set the common-mode voltage of an input channel. A low-side

internal ground switch is provided to allow power-down of an

external circuit (for example, a bridge circuit) between conversions.

Optional input buffers are provided for the analog inputs and the

external reference inputs. These buffers can be enabled for all

programmable gain amplifier (PGA) gain settings.

The ADCs contain two parallel filters: a sinc3 or sinc4 filter

in parallel with a sinc2 filter. The sinc3 or sinc4 filter is used

for precision measurements. The sinc2 filter is used for fast

measurements and for the detection of step changes in the input signal.

The ADuCM362-EP contains a low noise, low drift internal

band gap reference, but the device can be configured to accept

one or two external reference sources in ratiometric measurement

configurations. An option to buffer the external reference inputs

is provided on chip. A single-channel buffered voltage output

DAC is also provided on chip.

The ADuCM362-EP integrates a range of on-chip peripherals

that can be configured under microcontroller software control

as required in the application. The peripherals include two

UARTs, an I2C, and dual SPI serial I/O communication

controllers, a 19-pin general-purpose input/output (GPIO)

port, two general-purpose timers, a wake-up timer, and a

system watchdog timer. A 16-bit PWM controller with six

output channels is also provided.

The ADuCM362-EP is specifically designed to operate in batterypowered

applications where low power operation is critical. The

microcontroller core can be configured in a normal operating

mode that consumes 290 μA/MHz (including flash/SRAM IDD).

An overall system current consumption of 1 mA can be achieved

with both ADCs on (input buffers off), a PGA gain of 4, one

SPI port on, and all timers on.

The ADuCM362-EP can be configured in a number of low

power operating modes under direct program control, including a

hibernate mode (internal wake-up timer active) that consumes

only 4 μA. In hibernate mode, peripherals, such as external

interrupts or the internal wake-up timer, can wake up the devices.

This mode allows the devices to operate with ultralow power while

still responding to asynchronous external or periodic events.

On-chip factory firmware supports in-circuit serial download

via a serial wire interface (2-pin JTAG system) and UART.

Nonintrusive emulation is also supported via the serial wire

interface. These features are incorporated into a low cost

QuickStart™ Development System that supports this precision

analog microcontroller family.

The device operates from an external 1.8 V to 3.6 V voltage

supply and is specified over the −55°C to +125°C temperature range.

Additional application and technical information can be found

in the ADuCM362 data sheet.

FEATURES

Analog input/output: dual 24-bit ADCs

Programmable ADC conversion rate (3.5 Hz to 3.906 kHz)

Simultaneous 50 Hz/60 Hz noise rejection

At 50 Hz continuous conversion mode

At 16.67 Hz single conversion mode

Flexible input mux for input channel selection to both ADCs

Two 24-bit multichannel ADCs (ADC0 and ADC1)

6 differential or 12 single-ended input channels

4 internal channels for monitoring DAC, temperature

sensor, IOVDD/4, and AVDD/4 (ADC1 only)

Programmable gain (1 to 128)

Gain of 1 with input buffer on/off supported

RMS noise: 0.052 μV at 3.53 Hz and 0.2 μV at 50 Hz

Programmable sensor excitation current sources

On-chip precision voltage reference

Two external reference options supported by both ADCs

Single 12-bit voltage output DAC

NPN mode for 4 mA to 20 mA loop applications

Microcontroller

ARM Cortex-M3 32-bit processor

Serial wire download and debug

Internal watch crystal for wake-up timer

16 MHz oscillator frequency with 8-way programmable divider

APPLICATIONS

Weapons and munitions

Avionics

Unmanned systems

Intelligent precision sensing systems