TI’s micro-power OPA333x opamp goes where few opamps have gone before

No matter how advanced your digital circuitry is: sometimes, you need an OpAmp. Technology improvements allow for low-power rail to rail OpAmps such as the OPA333.

Running operational amplifiers from a single supply is a sure-fire way to cause problems while training. Generating positive and negative supply voltages gets tedious when working on a low-power design. Having to make do with supply voltages as low at 1.8 V complicates things further.

TI addresses that problem with the low-power operational amplifier at hand. The chip works with supply voltages as low as 1.8 V. Should you feel like splitting them, the limits become -0.9 V and 0.9 V. The largest allowed supply is a generous 5.5 V – a value well known to microcontroller circuit designers. Another interesting aspect is the advanced rail to rail capability: the output voltage can approach the supply voltages to a margin of 50mV. This makes the part ideally suited to sensor information conditioning.

Texas Instruments intends the part for precision applications. In addition to the low CMRR, the part has a temperature drift in the range of but 0.05uV/°C. Its quiescent current is around 17yA – compare this to older parts to find out that our new contender is much more efficient.

Treasure trove of knowledge!

Texas Instruments data sheet team outdid itself when describing the OPA333. The datasheet doesn’t limit itself to the specifications. It provides valuable insight into circuit design and PCB layout for low power OpAmps. This makes the document valuable even if you work with other operational amplifiers. From a packaging point of view, Texas Instruments is flexible. The parts are available in SOT23, SOT and SOIC housings, the latter of which can be soldered by hand.

Should you need two operational amplifiers of the type, switch to the OPA2333. It combines two of the parts in a fashion similar to the one shown in the figure.

Author: Tam Hanna
Published: March 12, 2021