Fully differential amplifier drives 18-bit ADCs while consuming 5-mW

May 03, 2012 // By Paul Buckley
Linear Technology has released a low power fully differential amplifier that can drive high precision 16- and 18-bit SAR ADCs at only 1 mA supply current.

With 200 µV max input offset voltage and 3.9 nV/√Hz input-referred noise, it is well suited for precision industrial and data acquisition applications.

The LTC6362 has an output common-mode pin with a 0.5 V to 4.5 V range, and 18-bit settling time of 550 ns with an 8 V P-P output step, making it ideal for driving ADCs such as the LTC2379-18 in multiplexed input and control loop applications. This 18-bit SAR ADC features digital gain compression, which sets its full scale input range to 10% to 90% of the reference voltage. Together with the rail-to-rail output stage of the LTC6362, this feature eliminates the need for a negative supply rail, simplifying the circuit and minimizing power consumption.

The flexible architecture of the LTC6362 can convert single-ended DC-coupled, ground-referenced signals to differential, or DC level shift differential input signals.  The low input bias current, low offset voltage and rail-to-rail inputs of the LTC6362 also enable its use in a high-impedance configuration to interface directly to sensors early in the signal chain.

Availability and Pricing

The LTC6362 is available in MSOP-8 and 3 mm x 3 mm DFN packages, with fully guaranteed specifications over the 0 to 70°C, -40 to 85°C and -40 to 125°C temperature ranges. Prices start at $1.59 each in 1,000-piece quantities.

More information about the LTC6362 differential amplifier at www.linear.com/product/LTC6362