Sensor ADCs

Linear Technology has introduced the LTC4260 and the LTC2462, a pair of 16-bit delta sigma ADCs that integrate a precision reference.

The integrated reference (2 ppm/°C typ, 10 ppm/°C max) allows precise measurements and alleviates the need for an external reference. Both ADCs guarantee 16-bit no missing code resolution.

This makes the devices suitable for remote sensor battery-powered applications and industrial sensors monitoring temperature or pressure.

Operating from a single 2.7 to 5.5 V supply, the ADCs are designed to measure single-ended (LTC2460) or differential (LTC2462) sensors via an SPI serial interface. With its internal 1.25 V reference, the 2460 can measure a single-ended input from 0 to 1.25 V, while the 2462 is capable of measuring a differential input up to ±1.25 V.

They achieve good 16-bit DC performance of 1LSB (typ) integral nonlinearity error, 2.2 µV^RMS transition noise and 0.25% gain error (max). The devices have an internal oscillator and operate up to 60 conversions/s, making it easy to measure temperature, pressure, voltage or other low-frequency sensor signals.

They draw 2.5 mA (max) supply current at the 60 Hz maximum sample rate with the internal reference active. After each conversion, the ADC enters a shutdown mode, reducing supply current to less than 1.5 mA (max). Supply current can be further reduced to less than 2 µA (max) in sleep mode.

The devices also incorporate a proprietary input sampling network that reduces the dynamic input current to less than 50 nA, making possible a wide range of external input filter and protection circuits.