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close the collected results agree with one another and is thus a measure of variability. The LPV8xx series may be considered as precision op-amps because they achieve ongoing high DC accuracy and AC performance. They have been designed "Always ON" sensing applications in wireless and wired equipment where low input offset (VOS) is required. In addition to having low offset and ultra-low quiescent current (IQ), 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. The op-amp is well-suited for end equipment that monitor current consumption, temperature, gas, or strain gauges. Zero-Drift In the very hot days we have in these Texas summers, I recall summers spent in California. My friends and I would travel the Los Angeles area out to the eastern California border, where the state of Arizona and California would meet. We would arrive at the town of Blythe, CA. There in the Palo Verde Valley of the Lower Colorado River Valley, we would go drifting down the Colorado River through the Colorado Desert in about one meter of water. We would utilize large inner tubes from semi-trucks or tractors and take all day to float some 25km– 50km, lazily refreshing ourselves with the cool river water and playing games. Idly meandering in the direction of the Gulf of California, the travel was slower than walking. However, after a full day in the tubes, you finally arrived at the destination spot. It was a day dedicated to slow drift. Slow drifting may be a good way to keep cool in the hot summer, but optimal precision amplifiers should have no offset voltage drift (Vos). Offset drift is the differential voltage measured between the inputs of an op-amp. Due to manufacturing processes, statistically, the inputs of an op-amp may be very close to each other but not perfectly matched. Additionally, as temperature changes, the differential value can move as well. The LPV821 nanopower op-amp employs a TI proprietary auto-calibration technique called zero-drift. This auto- calibration technique gets performed through an act of internal compensation. It saves engineering time and expense because the part corrects itself without the need for engineers to intervene. Zero-drift works to minimize input offset voltage drift that may be caused due to changes in temperature and does so without compounding 1/f noise (flicker noise, 3.9µVp-p). Low flicker noise provides for optimal performance for high- impedance sensor operation. Zero-drift provides very low input offset voltages (VOS: ±10μV, max) and minimal drift over time and temperature (dVOS/ dT, input offset voltage drift, TAmbient = –40°C to 125°C, VS=3.3VDC; ±0.02μV/°C, typ; ±0.096μV/°C, max). Due to its high DC precision, TI's zero-drift finds utilization in high- precision applications, particularly involving instrumentation that is working with low-level input signals. Zero-drift enables the op-amp to more closely perform to the characteristics of an ideal op-amp. It allows design engineers to obtain high DC precision. Nanopower Nanopower helps provide maximum battery life with nanopower products consuming <1µA per channel. The LPV821 consumes a best-in-class IQ = 650nA, VS = 1.7VDC– 3.6VDC, with an 8kHz bandwidth. The LPV821 amplifier also features an input stage with rail-to-rail input common mode range and an output stage that swings within 12mV of the rails, maintaining the widest dynamic range possible. The device is EMI hardened to reduce system sensitivity to unwanted RF signals from mobile phones, Wi-Fi, radio transmitters, and tag readers. Because the LPV821 zero-drift amplifier can operate with a single supply voltage as low as 1.7VDC, designers can count on continuous always ON sensing performance in low battery situations over its extended temperature range. The LPV821 (single-channel) is available in industry standard 5-pin SOT-23, providing a nominal footprint of 2.9mm × 1.6mm = 4.64mm2. 6 TLV906x Low Voltage Operational Amplifiers • Rail-to-Rail Input and Output • Low Input Offset Voltage: ±0.3mV • Unity-Gain Bandwidth: 10MHz Learn more

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