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16bit delta sigma ADCs integrate high accuracy reference

Linear Technology has introduced the LTC2470 and LTC2472, a pair of 16bit delta sigma ADCs that integrate a high accuracy reference in 3x3mm DFN and 12-lead MSOP packages. The device's integrated 1.25V reference offers 2ppm/ºC drift performance and 0.1% initial accuracy for precise measurements in space-constrained applications. Both ADCs provide assured 16bit no missing code resolution and selectable 250samples/s or 1ksample/s output rate. The devices are suitable for system and environmental monitoring and data acquisition systems requiring fast output rates. Operating from a single 2.7V to 5.5V supply, these ADCs are designed to measure single-ended (LTC2470) or differential (LTC2472) sensors via an SPI serial interface. With its internal 1.25V reference, the LTC2470 can measure a single-ended input between 0V and 1.25V, while the LTC2472 is capable of measuring a differential input up to ±1.25V.

The devices achieve 16bit DC performance of 2LSB (typical) integral nonlinearity error at 250samples/s, 3µVRMS transition noise and 0.25% gain error (maximum). An internal oscillator eliminates the need for external components to perform conversions. The devices draw 3.5mA supply current during a conversion. After each conversion, the ADC enters a nap mode, reducing supply current to less than 1.5mA (maximum). Supply current can be further reduced by placing the converter in sleep mode to achieve less than 2µA (maximum). The devices also incorporate a proprietary input sampling network that reduces the dynamic input current to less than 50nA, making a wide range of external input protection and filter circuits possible. The devices are each offered in small 12pin 3x3mm DFN and MSOP packages. They are available in both commercial and industrial temperature grade versions.