To obtain the low noise and drift specifications demanded in high performance temperature control solutions, designers must consider multiple components and the impact of each on the overall system. ADI offers products and signal chain solutions tailed for RTD and thermocouple applications.
The AD7091R is a 12-bit successive approximation analog-to-digital converter (ADC) that offers ultralow power consumption (typically 349 µA at 3 V and
1 MSPS) while achieving fast throughput rates (1 MSPS with a 50 MHz SCLK). The AD7091R uses advanced design and process techniques to achieve this very low power dissipation at high throughput rates. The part also features an on-chip, accurate 2.5 V reference.
Operating from a single 2.7 V to 5.25 V power supply, the part contains a wide bandwidth track-and-hold amplifier that can handle input frequencies in excess of 7 MHz. The AD7091R also features an on-chip conversion clock and high speed serial interface. The conversion process and data acquisition are controlled using a CONVST signal and an internal oscillator.
- Lowest Power 12-Bit SAR ADC Available
- 349 μA typical at 3 V and 1 MSPS
- 264 nA typical at 3 V in power-down mode
- Flexible Power/Throughput Rate Management
- Average power scales with the throughput rate
- Power-down mode allows the average power consumption to be reduced for intermittent or one shot conversion scenarios
- ±1 LSB max INL
- Single supply operation with separate VDRIVE pin. The AD7091R operates from a single 2.7 V to 5.25 V supply. The VDRIVE function allows the serial SPI® interface to independently connect directly to 1.8 V to 5 V processors
- On-chip, accurate 2.5 V reference, which can also be overdriven with external 2.7 V to 5.25 V reference
- Temperature range from −40°C to +125°C spans numerous end markets
- Available in 2 mm x 3 mm 10-lead LFCSP, with alternative pinned MSOP package
Instrumentation and Measurement
- Battery and USB powered systems
- Data acquisition systems
- Handheld meters
- Field instruments
- Battery powered devices
- Optical systems
- Mobile communications
- Battery Operated Medical instruments
- Electrocardiograms and heart rate monitors
The ADT7420 is a high accuracy digital temperature sensor offering breakthrough performance over a wide industrial range, housed in a 4 mm × 4 mm LFCSP package. It contains an internal band gap reference, a temperature sensor, and a 16-bit ADC to monitor and digitize the temperature to 0.0078°C resolution. The ADC resolution, by default, is set to 13 bits (0.0625°C). The ADC resolution is a user programmable mode that can be changed through the serial interface.
The ADT7420 is guaranteed to operate over supply voltages from 2.7 V to 5.5 V. Operating at 3.3 V, the average supply current is typi-cally 210 μA. The ADT7420 has a shutdown mode that powers down the device and offers a shutdown current of typically 2.0 μA at 3.3 V. The ADT7420 is rated for operation over the −40°C to +150°C temperature range.
Pin A0 and Pin A1 are available for address selection, giving the ADT7420 four possible I2C addresses. The CT pin is an open-drain output that becomes active when the temperature exceeds a programmable critical temperature limit. The INT pin is also an open-drain output that becomes active when the tempera-ture exceeds a programmable limit. The INT pin and CT pin can operate in comparator and interrupt event modes.Product Highlights
- Ease of use, no calibration or correction required by the user.
- Low power consumption.
- Excellent long-term stability and reliability.
- High accuracy for industrial, instrumentation, and medical applications.
- Packaged in a 16-lead, 4 mm × 4 mm LFCSP RoHS-compliant package.
- RTD and thermistor replacement
- Cold junction compensation
- Medical equipment
- Industrial control and test
- Food transportation and storage
- Environmental monitoring and HVAC
- Laser diode temperature control
- Building Control and Automation
- LED General Lighting
Interactive Signal Chains
- AN-892: Temperature Measurement Theory and Practical Techniques (Rev. 0) PDF
- AN-1313: Configuring the AD5422 to Combine Output Current and Output Voltage to a Single Output Pin (Rev. 0) PDF
- AN-1161: EMC-Compliant RS-485 Communication Networks (Rev. 0) PDF
- AN-880: ADC Requirements for Temperature Measurement Systems (Rev. 0) PDF