OPA189 Datasheet, PDF (13/34 Pages) Texas Instruments – Precision, 36-V, 14-MHz, MUX-Friendly Low-Noise, Rail-to-Rail Output, Zero-Drift Operational Amplifiers

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OPA189, OPA2189, OPA4189
SBOS830 – JUNE 2017
8.3 Feature Description
The OPA189, OPA2189, and OPA4189 series of op amps can be used with single or dual supplies from an
operating range of V_S = 4.5 V (±2.25 V) up to V_S = 36 V (±18 V). These devices do not require symmetrical
supplies; they only require a minimum supply voltage of 4.5 V (±2.25 V). For V_S less than ±2.5 V, the
common-mode input range does not include midsupply. Supply voltages higher than 40 V can permanently
damage the device; see the Absolute Maximum Ratings table for details. Key parameters are given over the
specified temperature range, T_A = –40°C to +125°C, in Electrical Characteristics. Key parameters that vary over
the supply voltage, temperature range, or frequency are shown in Typical Characteristics.
The OPAx189 is unity-gain stable and free from unexpected output phase reversal. This device uses a
proprietary, periodic autocalibration technique to provide low input offset voltage and very low input offset voltage
drift over time and temperature. For lowest offset voltage and precision performance, optimize circuit layout and
mechanical conditions. Avoid temperature gradients that create thermoelectric (Seebeck) effects in the
thermocouple junctions formed from connecting dissimilar conductors. Cancel these thermally-generated
potentials by ensuring they are equal on both input pins. Other layout and design considerations include:
• Use low thermoelectric-coefficient conditions (avoid dissimilar metals).
• Thermally isolate components from power supplies or other heat sources.
• Shield operational amplifier and input circuitry from air currents, such as cooling fans.
Follow these guidelines to reduce the likelihood of junctions being at different temperatures, which may cause
thermoelectric voltages of 0.1 µV/°C or higher, depending on the materials used. See Layout Guidelines for
details and layout example.
8.3.1 Operating Characteristics
The OPAx189 is specified for operation from 4.5 V to 36 V (±2.25 V to ±18 V). Many specifications apply from
–40°C to +125°C. Parameters that can exhibit significant variance with regard to operating voltage or
temperature are presented in the Typical Characteristics section.
8.3.2 Phase-Reversal Protection
The OPAx189 has an internal phase-reversal protection. Many op amps exhibit a phase reversal when the input
is driven beyond the linear common-mode range. This condition is most often encountered in noninverting
circuits when the input is driven beyond the specified common-mode voltage range, causing the output to
reverse into the opposite rail. The OPAx189 input prevents phase reversal with excessive common-mode
voltage. Instead, the output limits into the appropriate rail. This performance is shown in Figure 4.
V_IN
V_OUT
Time (45 ms/div)
C017
Figure 4. No Phase Reversal
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Product Folder Links: OPA189 OPA2189 OPA4189