Op Amp Features Ultra-High Precision

Texas Instruments (TI) has introduced an op amp that combines ultra-high precision with low supply current. The LPV821 zero-drift, nanopower op amp enables engineers to attain the highest DC precision, while consuming 60% less power than competitive zero-drift devices, according to TI. The LPV821 is designed for use in precision applications such as wireless sensing nodes, home and factory automation equipment, and portable electronics.

LS-First-Page

The LPV821 is a single-channel, nanopower, zero-drift operational amplifier for “Always ON” sensing applications in wireless and wired equipment where low input offset is required. With the combination of low initial offset, low offset drift, and 8 kHz of bandwidth from 650 nA of quiescent current, the LPV821 is the industry’s lowest power zero-drift amplifier that can be used for end equipment that monitor current consumption, temperature, gas, or strain gauges.

The LPV821 zero-drift op amp uses a proprietary auto-calibration technique to simultaneously provide low offset voltage (10 μV, maximum) and minimal drift over time and temperature. In addition to having low offset and ultra-low quiescent current, the LPV821 amplifier has pico-amp bias currents which reduce errors commonly introduced in applications monitoring sensors with high output impedance and amplifier configurations with megaohm feedback resistors.

Engineers can pair the LPV821 op amp with the TLV3691 nanopower comparator or ADS7142 nanopower analog-to-digital converter (ADC) to program a threshold that will automatically wake up a microcontroller (MCU) such as the CC1310 SimpleLink Sub-1 GHz MCU, further reducing system power consumption.

Designers can download the TINA-TI SPICE model to simulate their designs and predict circuit behavior when using the LPV821 op amp. Engineers can also jump-start gas-sensing system designs using the LPV821 op amp with the Always-On Low-Power Gas Sensing with 10+ Year Coin Cell Battery Life Reference Design and Micropower Electrochemical Gas Sensor Amplifier Reference Design.

Pre-production samples of the LPV821 op amp are now available through the TI store and authorized distributors in a 5-pin small-outline transistor (SOT-23) package. Pricing starts at $0.80 in 1,000-unit quantities.

Texas Instruments | www.ti.com

Zero-Drift Op Amp Consumes Only 1.3 μAmps

Analog Devices,  which recently acquired Linear Technology, has announced the LTC2063 zero-drift op amp which draws just 1.3μA typ (2μA max) on a 1.8V supply. This micropower amplifier maintains high precision: maximum input offset voltage is 5μV at 25°C, maximum drift is 0.06μV/°C from –40°C to 125°C. Maximum input bias current is 15pA at 25°C, and 100pA from –40°C to 125°C. These high precision input characteristics allow the use of large value feedback network resistors, keeping power consumption low without compromising accuracy, even at elevated temperature.

LTC2063

Rail-to-rail inputs and outputs simplify single supply use and enhance dynamic range. An integrated EMI filter provides 114dB electromagnetic interference rejection at 1.8GHz. With low 1/f noise inherent to its zero-drift architecture the LTC2063 is well suited for amplifying and conditioning low frequency sensor signals in high temperature industrial and automotive systems as well as portable and wireless sensor network applications.

The LTC2063 is available in SOT-23 and SC70 packages. The SC70 version includes a shutdown mode which reduces current consumption to just 90nA when the amplifier is not in use. This enables ultralow power duty cycled sensor applications. For example, a precision low duty cycle oxygen sensor circuit shown in the data sheet consumes less than 200nA average current.

The LTC2063 works well with Dust Networks’ SmartMesh wireless sensor networks, expanding the reach of precision measurements to places previously not practical. An example is the DC2369A wireless current sense reference board which uses the LTC2063 and LTP5901-IPM SmartMesh IP module and other micropower components to create an isolated floating current sense measurement platform which operates for years on small batteries.

The LTC2063 operates on supply voltages from 1.7V to 5.25V and is fully specified from –40°C to 125°C. Pricing starts at $1.50 each in 1,000-piece quantities.

Linear Technology | www.linear.com