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ADI ADuCM360熱電偶溫度監(jiān)測解決方案

2012-06-18
關(guān)鍵詞: DSP ADuCM360 溫度監(jiān)測

ADI公司的ADuCM360是全集成的4kSPS 24位數(shù)據(jù)采集系統(tǒng),集成了兩個高性能多路Sigma-Delta (Σ-Δ) ADC,32位ARM Cortex M3®MCU和閃存/EE存儲器,能直接雙線和外接精密傳感器接口,并采用電池供電.模擬輸入/輸出,單端和全差分輸入,輸入范圍±6.64 mV 到±1.2 V,可編程ADC輸出速率(4Hz到4kHz),可編程增益從1到128,RMS噪音為43nV @3.75Hz和180nV @ 50Hz,主要用于工業(yè)自動化和過程控制,智能的精密檢測系統(tǒng),4mA到20mA回路智能傳感器系統(tǒng),醫(yī)療設(shè)備和病人監(jiān)護.本文介紹了ADuCM360主要特性,方框圖,以及采用ADuCM360和外接熱電偶的基于USB溫度監(jiān)測器特性,電路圖和材料清單與PCB布局圖.

The ADuCM360 is a fully integrated, 4 kSPS, 24-bit data acqui-sition system incorporating dual, high performance multi-channel sigma-delta (Σ-Δ) analog-to-digital converters (ADCs), 32-bit ARM Cortex M3®MCU, and Flash/EE memory on a single chip. The part is designed for direct interfacing to external precision sensors in both wired and battery powered applications.

The ADuCM361 contains all the features of the ADuCM360 except the primary ADC, ADC0 is not available – only the auxiliary ADC, ADC1 is available.

The device contains an on-chip 32 KHz oscillator and an internal 16MHz high-frequency oscillator. This clock is routed through a programmable clock divider from which the MCU core clock operating frequency is generated. The maximum core clock speed is 16MHz and this is not limited by operating voltage or temperature.

The microcontroller core is a low power Cortex-M3 core from ARM. It is a 32-bit RISC machine, offering up to 20 MIPS peak performance. The Cortex-M3 MCU incorporates a flexible 11-channel DMA controller supporting all wired (SPI, UART, I2C) communication peripherals. 128k Bytes of non-volatile Flash/EE and 8k Bytes of SRAM are also integrated on-chip.

The Analog sub-system 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, burn-out current sources and a bias voltage generator of AVDD_REG/2 (900mV) to set the common-mode voltage of an input channel. A low-side internal ground switch is provided to allow powering down of a bridge between conversions. The ADCs contain two parallel filters – a Sinc3 or Sinc4 in parallel with a Sinc2. The Sinc3 or Sinc4 filter is for precision measurements. The Sinc2 filter is for fast measurements and for detection of step changes in the input signal The device also contains a low noise, low drift internal band-gap reference or can be configured to accept up to 2 external reference sources in ratiometric measurement configurations. An option to buffer the external reference inputs is also provided on-chip. A single-channel buffered voltage output DAC is also provided on chip. The ADuCM360/ADuCM361 also integrates a range of on-chip peripherals which can be configured under microcontroller software control as required in the application. These peripherals include UART, I2C and dual SPI Serial I/O communication controllers, 19-Pin GPIO Ports, 2 General Purpose Timers, Wake-up Timer and System Watchdog Timer. A 16-bit PWM with six output channels is also provided.

The ADuCM360/ADuCM361 is specifically designed to operate in battery powered applications where low power operation is critical. The microcontroller core can be configured in a normal operating mode consuming 290μA/MHz (including Flash/SRAM Idd) resulting in an overall system current consumption of 1mA when all peripherals are active.

The part can also be configured in a number of low power operating modes under direct program control, including hibernate mode (internal wake-up timer active) consuming only 4μA. In hibernate mode, peripherals such as external interrupts or the internal wake up timer can wake up the device. This allows the part to operate in an ultra-low power operating mode and still respond 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 while non-intrusive emulation is also supported via the serial wire interface. These features are incorporated into a low-cost QuickStart Development System supporting this Precision Analog Microcontroller family.

The part operates from an external 1.8V to 3.6V voltage supply and is specified over an industrial temperature range of -40°C to 125℃.

The ADuCM360 is a fully integrated, 4 kSPS, 24-bit data acqui-sition system incorporating dual, high performance multi-channel sigma-delta (Σ-Δ) analog-to-digital converters (ADCs), 32-bit ARM Cortex M3®MCU, and Flash/EE memory on a single chip. The part is designed for direct interfacing to external precision sensors in both wired and battery powered applications.

The ADuCM361 contains all the features of the ADuCM360 except the primary ADC, ADC0 is not available – only the auxiliary ADC, ADC1 is available.

The device contains an on-chip 32 KHz oscillator and an internal 16MHz high-frequency oscillator. This clock is routed through a programmable clock divider from which the MCU core clock operating frequency is generated. The maximum core clock speed is 16MHz and this is not limited by operating voltage or temperature.

The microcontroller core is a low power Cortex-M3 core from ARM. It is a 32-bit RISC machine, offering up to 20 MIPS peak performance. The Cortex-M3 MCU incorporates a flexible 11-channel DMA controller supporting all wired (SPI, UART, I2C) communication peripherals. 128k Bytes of non-volatile Flash/EE and 8k Bytes of SRAM are also integrated on-chip.

The Analog sub-system 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, burn-out current sources and a bias voltage generator of AVDD_REG/2 (900mV) to set the common-mode voltage of an input channel. A low-side internal ground switch is provided to allow powering down of a bridge between conversions. The ADCs contain two parallel filters – a Sinc3 or Sinc4 in parallel with a Sinc2.

The Sinc3 or Sinc4 filter is for precision measurements. The Sinc2 filter is for fast measurements and for detection of step changes in the input signal The device also contains a low noise, low drift internal band-gap reference or can be configured to accept up to 2 external reference sources in ratiometric measurement configurations. An option to buffer the external reference inputs is also provided on-chip. A single-channel buffered voltage output DAC is also provided on chip. The ADuCM360/ADuCM361 also integrates a range of on-chip peripherals which can be configured under microcontroller software control as required in the application. These peripherals include UART, I2C and dual SPI Serial I/O communication controllers, 19-Pin GPIO Ports, 2 General Purpose Timers, Wake-up Timer and System Watchdog Timer. A 16-bit PWM with six output channels is also provided.

The ADuCM360/ADuCM361 is specifically designed to operate in battery powered applications where low power operation is critical. The microcontroller core can be configured in a normal operating mode consuming 290μA/MHz (including Flash/SRAM Idd) resulting in an overall system current consumption of 1mA when all peripherals are active.

The part can also be configured in a number of low power operating modes under direct program control, including hibernate mode (internal wake-up timer active) consuming only 4μA. In hibernate mode, peripherals such as external interrupts or the internal wake up timer can wake up the device. This allows the part to operate in an ultra-low power operating mode and still respond 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 while non-intrusive emulation is also supported via the serial wire interface. These features are incorporated into a low-cost QuickStart Development System supporting this Precision Analog Microcontroller family.

The part operates from an external 1.8V to 3.6V voltage supply and is specified over an industrial temperature range of -40℃ to 125℃.

ADuCM360主要特性:

Analog Input/Output

Dual (24-bit) ADCs (ADuCM360)

Single (24-bit) ADC (ADuCM361)

Single Ended and fully Differential inputs

Programmable ADC output rate (4 Hz to 4 kHz)

Simultaneous 50Hz/60Hz rejection

50SPS Continuous Conversion Mode

16.67SPS Single Conversion Mode

Flexible input MUX for input channel selection to both ADCs

Primary and Auxiliary (24-bit) ADC channel

6 differential or 11 Single-Ended input channels

4 internal channels for monitoring DAC, Temperature sensor, IOVDD and AVDD (ADC1 only)

Programmable Gain (1 to 128)

Selectable input range: ±6.64 mV to ±1.2 V

RMS noise: 43nV @3.75Hz, 180nV @ 50Hz

Programmable sensor excitation current sources

10/50/100/150/200/250/300/400/500/600/800uA and 1mA current source options

On-chip precision Voltage reference (±4 ppm/℃)

Single 12-bit voltage output DAC

NPN mode for 4-20mA loop applications

Microcontroller

ARM Cortex™M3 32-bit processor Serial Wire download and debug Internal Watch crystal for wakeup timer 16

MHz Oscillator with 8-way Programmable Divider

Memory 128k Bytes Flash/EE Memory, 8k Bytes SRAM In-circuit debug/download via Serial Wire and UART

Power Operates directly from a 3.0V battery Supply Range: 1.8V to 3.6V (max)

Power Consumption

MCU Active Mode: Core consumes 290μA / MHz

Active Mode: 1.0mA (All peripherals active), core operating at 500KHz

Power down mode: 4μA (WU Timer Active)

On-Chip Peripherals

UART, I2C and 2 x SPI Serial I/O

16-bit PWM Controller

19-Pin Multi-Function GPIO Port

2 General Purpose Timers

Wake-up Timer/Watchdog Timer

Multi-Channel DMA and Interrupt Controller

Package and Temperature Range

48 lead LFCSP (7mm x 7mm) package –40℃ to 125℃

Development Tools

Low-Cost QuickStart™Development System

Third-Party Compiler and emulator tool Support

Multiple Functional Safety features for improved diagnostics

ADuCM360主要應(yīng)用:

Industrial automation and process control

Intelligent, precision sensing systems

4 mA to 20 mA loop-powered smart sensor systems

Medical devices, patient monitoring


圖1.ADuCM360方框圖

采用ADuCM360精密模擬微控制器和外接熱電偶的基于USB溫度監(jiān)測器

This circuit uses the ADuCM360/ADuCM361 precision analog microcontroller in an accurate thermocouple temperature monitoring application. The ADuCM360/ADuCM361 integrates dual 24-bit sigma-delta (Σ-Δ) analog-to-digital converters (ADCs), dual programmable current sources, a 12-bit digital-to-analog converter (DAC), and a 1.2 V internal reference, as well as an ARM Cortex-M3 core, 126 kB flash, 8 kB SRAM, and various digital peripherals such as UART, timers, SPIs, and I2C interfaces. In the circuit, the ADuCM360/ADuCM361 is connected to a thermocouple and a 100 Ω platinum resistance temperature detector (RTD). The RTD is used for cold junction compensation. In the source code, an ADC sampling rate of 4 Hz is chosen. When the ADC input programmable gain amplifier (PGA) is configured for a gain of 32, the noise-free code resolution of the ADuCM360/ ADuCM361 is greater than 18 bits.


圖2.EVAL-ADuCM360TCZ板外形圖

圖3.采用ADuCM360的溫度監(jiān)測器簡化電路圖



圖4.EVAL-ADuCM360TCZ電路圖(1)

圖5.EVAL-ADuCM360TCZ電路圖(2)


圖6.EVAL-ADuCM360TCZ電路圖(3)

圖7.EVAL-ADuCM360TCZ PCB布局圖(頂層)


圖8.EVAL-ADuCM360TCZ PCB布局圖(底層)
EVAL-ADuCM360TCZ材料清單見:

詳情請見:
http://www.analog.com/static/imported-files/data_sheets/ADuCM360_361.pdf

http://www.analog.com/static/imported-files/circuit_notes/CN0221.pdf



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