Part Number: OPA2189IDGKR

Manufacturer: Texas Instruments

Description: CMOS precision operational amplifier 8-VSSOP -40 to 125.

Shipped from: Shenzhen/HK Warehouse

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OPA2189IDGKR Description

High-precision operational amplifiers OPA189, OPA2189, and OPA4189 (collectively called OPAx189) provide rail-to-rail output operation. They feature an innovative architecture that is MUX-friendly in addition to a controlled start-up system. These devices also have ultra-low noise, fast settling, and zero drift. The OPAx189 is a strong option for precision instrumentation, signal measurement, and active filtering applications as a result of these qualities and its excellent ac performance.

Additionally, the single-channel version has just 0.4 V of offset voltage and 0.005 V/°C of drift over temperature. In addition, the MUX-friendly input architecture stops inrush current from flowing when significant input differential voltages are applied. This enhances the settling performance of multi-channel systems and provides handling and robust ESD protection during shipment and assembly. The variations’ temperature range is from –40 degrees to +125 degrees.

Detailed Description


The OPAx189 operational amplifiers are an excellent option for many precision applications due to their accuracy offset, drift, and overall performance. With a precision offset drift of only 0.005 V/°C, this meter remains stable across the board. In addition, such devices’ CMRR, PSRR, and AOL are exceptionally high. Decoupling capacitors adjacent to the device pins are necessary for all amplifier applications that use noisy or high-impedance power supply. Capacitors with a 0.1-F rating are usually sufficient.

The OPAx189 is a series of MUX-friendly, zero-drift, rail-to-rail output operational amplifiers. These devices can handle voltages between 4.5 V and 36 V, have unity-gain stability, and can be used for various industrial and scientific tasks. The zero-drift design provides ultra-low input offset voltage, and nearly zero offset voltage drift concerning temperature and time. When operating below the chopper frequency, this design choice also provides exceptional ac performance, including ultra-low broadband noise, 0% flicker noise, and excellent distortion performance.

Feature Description

The op-amps in the OPAx189 series have a wide supply voltage range, from VS = 4.5 V (2.25 V) to VS = 36 V (18 V), making them suitable for use with a single supply or a pair of supplies. These components can operate from a source as low as 4.5 V (2.25 V) and are asymmetrical in their supply requirements. Midsupply is not part of the common-mode input range for VS less than 2.5 V. Using a power supply higher than 40 V voltage can irreversibly damage the component.

The OPAx189 is stable at unity gain and has no output phase reversal issues. This device’s input offset voltage is kept low, and its offset voltage drifts very little over time and temperature thanks to a patented autocalibration method. Circuit configuration and mechanical circumstances should be optimized for the lowest possible offset voltage and the highest possible accuracy performance. It is best to keep thermocouple connections from experiencing thermoelectric (Seebeck) effects due to temperature gradients. Equalize the voltage at each input pin to nullify the effects of thermal generation. When planning the layout and design, you should also think about the following:

  • Apply conditions with a small thermoelectric coefficient (avoid dissimilar metals).
  • Keep electronics and other parts from getting too hot by isolating them from their power sources.
  • Protect the input and operational amplifier circuitry from moving air.

Adhering to these recommendations will lessen the possibility of thermoelectric voltages of 0.1 V/°C or greater, which might result from junctions at different temperatures.

● Phase-Reversal Protection

An internal phase-reversal safeguard is included in the OPAx189. After the input is driven past the linear common-mode range, many operational amplifiers undergo a phase reversal. The output will drop into the opposing rail in noninverting circuits if the information is driven outside the designated common-mode voltage range. A high common-mode voltage will not cause the input of an OPAx189 to flip the phase. As a replacement, the output is capped at the relevant rail.

● Input Bias Current Clock Feedthrough

A zero-drift amplifier, such as the OPAx189, compensates for the amplifier’s inherent offset and drift by switching the inputs. The amplifier’s input bias current can be influenced by transients caused by charge injection from the integrated switches on the inputs. Though these pulses can’t be amplified due to their brief length, the amplifier’s feedback network may link them to the output. Applying a low-pass filter, such as an RC network, to the amplifier’s output is the most efficient way to stop transients in the input bias current from creating extra noise at the amplifier’s output.

● Electrical Overstress

The operational amplifier’s resistance to electrical overstress is frequently questioned among designers. The device inputs are typically under scrutiny, but the supply voltage pins and the output pin might also come up. The voltage breakdown characteristics of the specific semiconductor production process and the associated circuits establish electrical stress limitations for these various pin functions. In addition, these circuits feature built-in electrostatic discharge (ESD) protection to shield components from damage caused by static electricity before and during product assembly.

● MUX-Friendly Inputs

An input differential voltage can be applied to the OPAx189 thanks to its unique input stage architecture, which also keeps the input impedance high. Anti-parallel diodes typically shield input transistors in high-voltage CMOS or bipolar-junction amplifiers to prevent irreversible damage from VGS voltages that exceed the semiconductor process’s limits. Using a big input step, switching between channels, or using the amplifier as a comparator can all result in excessively high VGS voltages.

● Basic Noise Calculations

Careful investigation of all potential noise sources is essential for designing low-noise circuits. It is crucial to consider source resistance’s impact on the total op amp noise performance, as external noise sources can dominate many situations. The root-sum-square of all noise sources in a circuit is the total noise in the circuit.


The OPA2189 from Texas Instruments is an ultra-low-noise,  high-precision, fast-settling, zero-drift op-amp with MUX-friendly architecture and a controlled start-up system that allows for a rail-to-rail output operation. The OPA2189 is well suited for precision instrumentation, signal measurement, and active filtering thanks to its low offset voltage of only 0.4 mV and low-temperature drift of about 0.005 mV/°C (for the single-channel version). In addition to offering strong ESD protection during shipping, handling, and assembly, the MUX-friendly input architecture also reduces inrush current when applying large input differential voltages, which benefits settling performance in multi-channel systems. The device is designed to function between -40 degrees Celsius and +125 degrees Celsius.

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