OPA343UA - 5.5V, 5.5MHz RRIO CMOS Operational Amplifier | Texas Instruments
MPN: OPA343UA ✓ ActiveOPA343UA Overview
An operational amplifier (op amp) is a voltage-amplifying building block with very high open-loop gain, used in feedback to create amplifiers, buffers, comparators, filters and signal converters. The rail-to-rail input/output (RRIO) architecture places the input common-mode range and the output swing at or beyond the supply rails, which matters when a system has little headroom above its signal levels. Within the component hierarchy, the OPA343UA sits as an amplifier IC, a sub-category of integrated circuits, competing with discrete bipolar input stages for low-voltage, space-constrained analog front ends.
Key features of the OPA343UA include a 5.5 MHz gain-bandwidth product for single-supply operation down to 2.5 V, a rail-to-rail input common-mode range that extends 500 mV beyond the supply rails, and rail-to-rail output swing. The device is optimized for low-cost, miniature applications and uses CMOS construction, which supports low quiescent current and single-supply operation without external biasing networks. Because the input stage is CMOS, the amplifier draws negligible bias current, making it suitable for high-impedance sources and capacitive-feedback topologies such as integrators.
Technically, the OPA343 series trades the very high precision and speed of premium bipolar or CMOS amplifier families for low cost and low power at modest bandwidth. Its 5.5 MHz gain-bandwidth product supports closed-loop gains of 1 through roughly 10 with useful flatness, while the rail-to-rail stages keep the signal usable when the input swings approach the supply rails. The manufacturer states that rail-to-rail input/output and high-speed operation make the device ideal for driving sampling analog-to-digital converters, and it is equally suited to general-purpose and audio applications and to providing I/V (current-to-voltage) conversion.
Typical applications include low-voltage ADC front ends, sensor signal conditioning on 3.3 V or 5 V rails, headphone and audio line stages, active filters, and single-supply instrumentation where a 5 V maximum operating voltage keeps the design simple and safe for low-voltage CMOS logic sharing the same rail.
When designing around the OPA343UA, keep the input common-mode voltage inside the range that extends 500 mV beyond the rails, place the supply bypass capacitors close to pins 7 and 4, and confirm that the closed-loop gain and capacitive loading do not force the amplifier into a lightly compensated or unstable region when driving long ADC input networks.
This page consolidates the manufacturer ordering information, package and pin data, drop-in SOIC-8 alternatives, and application guidance for the OPA343UA, so engineers can evaluate the amplifier against other single-supply RRIO parts without searching through multiple catalog pages.
Drop-in alternatives for OPA343UA — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with OPA343UA (same form factor and footprint) — differing in Amplifier Type, Gain-Bandwidth Product, Maximum Supply Voltage, Package, Slew Rate.
OPA353UA
✅ Drop-InContact for price
View Datasheet →OPA340UA
✅ Drop-InContact for price
View Datasheet →OPA365AID
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
OPA320AID
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
OPA132UA
✅ Drop-In ⚠️ Specs UnverifiedContact for price
View Datasheet →OPA343UA Maximum Ratings & Electrical Characteristics
| Device Type | Single-channel CMOS operational amplifier |
| Number of Channels | 1 |
| Amplifier Type | Rail-to-Rail Input/Output (RRIO) |
| Maximum Supply Voltage | 5.5 V |
| Minimum Supply Voltage | 2.5 V |
| Supply Type | Single supply operation supported |
| Gain-Bandwidth Product | 5.5 MHz |
| Input Common-Mode Range | Extends 500 mV beyond the supply rails |
| Technology | CMOS (microAmplifier series) |
| Input Stage | FET-input CMOS |
| Package Type | SOIC (D) |
| Number of Pins | 8 |
| Operating Temperature Range | -40 °C to +85 °C |
| Mounting Type | Surface mount |
| Series | OPA343 (single / dual / quad identical specifications) |
OPA343UA Pin Configuration
| Pin 1 | NC — Not connected (per datasheet) |
| Pin 2 | -IN — Inverting input |
| Pin 3 | +IN — Non-inverting input |
| Pin 4 | V- — Negative supply / ground reference |
| Pin 5 | NC — Not connected (per datasheet) |
| Pin 6 | OUT — Output |
| Pin 7 | V+ — Positive supply |
| Pin 8 | NC — Not connected (per datasheet) |
Typical Applications
OPA343UA is suitable for 6 applications: Low-Voltage ADC Front End, Portable Audio and Headphone Buffering, Battery-Powered Sensor Signal Conditioning, Current-to-Voltage (I/V) Conversion for Sensor Interfaces, Active Filters and Signal Conditioning Networks, General-Purpose 5 V Analog Signal Conditioning.
Low-Voltage ADC Front End
The OPA343UA sits directly at the input of a sampling analog-to-digital converter on a 3.3 V or 5 V rail. Its rail-to-rail input common-mode range extends 500 mV beyond the supply rails, so the buffer accepts signal levels that would clip a non-RRIO amplifier near the rail, and the rail-to-rail output swing delivers the maximum usable converter input range. With a 5.5 MHz gain-bandwidth product the closed-loop buffer bandwidth is far above typical moderate-resolution conversion rates, so settling is not the limiting factor. The CMOS input stage draws negligible bias current, which keeps the buffer from loading the preceding sensor or divider network. Because it operates from 2.5 V, the same part can serve low-voltage converter rails where a 5 V-only amplifier would not fit.
Recommended
Portable Audio and Headphone Buffering
In battery-powered audio equipment the OPA343UA provides a low-voltage buffer stage between the source and the headphone or line amplifier. The rail-to-rail output swing allows the stage to use nearly the full 2.5 V to 5.5 V supply, which directly improves the usable output power and headroom in a compact design. The 5.5 MHz gain-bandwidth product comfortably handles audio-band signals and allows active equalizer or crossover topologies at unity gain without stability concerns. The CMOS input stage presents essentially no bias current, so it will not load a high-impedance headphone-sensing or mixer node. The low supply voltage also helps keep the amplifier inside the thermal envelope of a sealed portable enclosure where dissipation and quiescent current matter.
Recommended
Battery-Powered Sensor Signal Conditioning
The OPA343UA conditions low-level sensor signals in battery-operated industrial and wearable products where the supply budget is tight. Operating from as little as 2.5 V, the amplifier can run directly from a single cell plus a small boost stage or from a 3.3 V rail without any negative supply, which simplifies the ground reference plan for the rest of the board. The CMOS input stage avoids loading resistive dividers or high-impedance electrochemical and piezoelectric sources, and the rail-to-rail input range lets the design work with signals that swing close to the rail. With a 5.5 MHz gain-bandwidth product it is fast enough for filtered condition paths and for feeding a downstream ADC without a separate buffer.
Recommended
Current-to-Voltage (I/V) Conversion for Sensor Interfaces
The OPA343UA is designed to provide I/V conversion in optical, photodiode and chemical-sensing interfaces, one of the applications highlighted in the manufacturer description of the OPA343 series. The CMOS FET-input stage draws picoamp-class bias currents, so the op amp does not steal signal current from the sensor or introduce significant offset error in a transimpedance configuration. The rail-to-rail output swing keeps the usable output span wide even when the system supply is only 2.5 V to 5.5 V, which improves the dynamic range recovered from small sensor currents. The 5.5 MHz gain-bandwidth product allows a closed-loop transimpedance gain that still has useful bandwidth with realistic photodiode capacitance, and the low-voltage operation simplifies the biasing of the detector front end.
Recommended
Active Filters and Signal Conditioning Networks
The OPA343UA is used in Sallen-Key and multiple-feedback active filter sections that follow sensors or precede converters. A 5.5 MHz gain-bandwidth product allows meaningful closed-loop gain and Q at audio and low-frequency instrumentation bands, and the rail-to-rail input and output stages remove the clipping headroom problems that plague non-RRIO filters operating near the supply. Because the part runs from 2.5 V, filter sections can be powered from the same low-voltage rail as the source, simplifying the analog supply tree in mixed-signal equipment. The same characteristics also suit low-level signal conditioning in test and measurement front ends, where the amplifier buffers a resistive divider or a sensor bridge before the ADC.
Recommended
General-Purpose 5 V Analog Signal Conditioning
The OPA343UA serves as a general-purpose amplifier in 5 V industrial and consumer boards, where a low-cost, low-voltage, general-purpose part is all that is required. The single 8-pin SOIC (D) footprint is the most common analog package on the board, so spares, sockets and layout reuse are straightforward. Its rail-to-rail input range means the amplifier accepts inputs from near ground to near the 5 V rail without level shifting, and the 5.5 MHz gain-bandwidth product is adequate for most instrumentation, interface and housekeeping signal paths. Because the manufacturer specifies identical specifications across the single, dual and quad versions, a design can be moved between OPA343UA and its multi-channel siblings without re-characterising the stage.
Recommended
Recommended Products Summary
Engineering reference data for OPA343UA — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | OPA353UA | OPA340UA | OPA365AID | OPA320AID | OPA132UA |
|---|---|---|---|---|---|---|
| Package | SOIC-8 (D) | SOIC-8 (D) - same | SOIC-8 (D) - same | SOIC-8 (D) - same | SOIC-8 (D) - same | SOIC-8 (D) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Number of Channels | 1 | 1 | 1 | 1 | 1 | 1 |
| Rail-to-Rail Input / Output | Yes, RRIO | Yes, RRIO | Yes, rail-to-rail | Yes, RRIO | Yes, RRIO | Yes, rail-to-rail |
| Input Stage Technology | CMOS (FET-input) | CMOS (FET-input) | CMOS (FET-input) | CMOS (FET-input) | CMOS (FET-input) | CMOS (FET-input) |
Key Differentiators
- Maximum supply voltage matched to 5 V and 3.3 V system rails (vs OPA365AID)
- Right-sized bandwidth avoids over-specification while staying fast enough for converter interfaces (vs OPA320AID)
- Single-amplifier SOIC-8 footprint allows seamless substitution within the same family (vs OPA340UA)
- Series consistency across single, dual and quad versions (vs OPA132UA)
Design Notes
Decouple the OPA343UA at the device with a 0.1 uF ceramic capacitor from pin 7 (V+) to pin 4 (V-) placed directly adjacent to the pins, and add a bulk ceramic (1 uF to 10 uF) in parallel for supply transients. Because the part works down to 2.5 V single supply, pin 4 connects to the system ground and there is no negative rail to decouple; the total supply current is the sum of the amplifier quiescent current plus load current. Keep the loop from the bypass capacitor to the supply pins as short as possible to limit inductive impedance at the frequencies where the amplifier's 5.5 MHz gain-bandwidth product still has open-loop gain.
Do not assume the input can be driven beyond the supply rails. The OPA343UA input common-mode range extends 500 mV beyond the rails rather than to the rails plus several volts, so any source that overshoots the supply during startup, hot plug or relay switching needs series clamping or an external protection network. The same caution applies to the output: rail-to-rail output is not an unlimited output, so check the load current and feedback network against the output swing specification in the manufacturer data sheet before assuming a full-scale swing into a low-impedance load.
Use the standard single-amplifier SOIC-8 land pattern so the OPA343UA, OPA353UA, OPA340UA and other single-channel alternatives share one footprint. Keep the feedback resistors close to pins 2 and 3 to minimise parasitic capacitance in high-gain configurations, and route the output to pin 6 away from the input nets to preserve stability. For ADC driver applications, place the amplifier close to the converter input and keep the input trace short and guarded, since the rail-to-rail input stage plus long PCB traces can pick up interference that appears directly as conversion error.
The CMOS input stage of the OPA343UA draws negligible bias current, which is a benefit for high-impedance sources, but it also means the amplifier's noise performance, offset and drift dominate error budgets rather than bias-current terms. Keep node impedances reasonable around the input pins and provide a defined DC path to ground for capacitive-feedback topologies such as integrators and transimpedance stages. When the amplifier drives a sampling ADC, verify settling behaviour at the converter's acquisition time with the actual source impedance and stray capacitance rather than relying on the closed-loop bandwidth figure alone.
Compliance Information
The manufacturer product and part-details pages describe the OPA343UA as an active single-channel RRIO amplifier in the SOIC (D) package with a -40 °C to +85 °C range. RoHS, REACH, lead-free and halogen-free statements are not published on the pages consulted, so these fields remain unknown; confirm with the manufacturer material declaration before committing to a regulated design.
