OPA345UA - 3MHz RRIO Op Amp | Texas Instruments
Teilenummer: OPA345UA ✓ AktivOPA345UA Übersicht
An operational amplifier, commonly abbreviated op amp, is an analog active component that amplifies the voltage difference between two inputs. The OPA345 belongs to the rail-to-rail input and output, or RRIO, family, allowing its input and output voltages to approach the positive and negative supply limits. Within the broader hierarchy, it is an analog integrated circuit, an operational amplifier, and ultimately a semiconductor used for signal conditioning, sensing, buffering, and closed-loop control.
The 3 MHz gain-bandwidth product supports signal amplification where bandwidth is important but low power and small package size remain primary constraints. Its single-amplifier configuration makes it suitable for circuits needing one independently controlled amplifier rather than a multi-amplifier package. Rail-to-rail input capability improves usable signal range in low-voltage systems, particularly when sensor outputs can move close to the supply rails. The manufacturer describes the OPA345 as a low-power CMOS operational amplifier for precision, miniature applications.
OPA345UA operates from 2.5 V to 5.5 V and includes approximately 300 mV of input headroom beyond the supply rails. The 300 mV extension helps preserve common-mode operation when a driven signal approaches a rail, although designers must still verify the complete operating range under temperature, load, and output-voltage conditions. The 8-pin SOIC package provides a conventional surface-mount footprint compatible with standard assembly and inspection processes.
Typical uses include low-voltage sensor conditioning, portable instrumentation, audio signal paths, data acquisition, and general-purpose analog filtering. In an instrumentation design, the amplifier can buffer a high-impedance sensor before conversion by an ADC. In a portable instrument, the single-supply architecture simplifies rail planning. Designers should nevertheless confirm offset voltage, input bias current, noise density, slew rate, output-current capability, and stability requirements against the manufacturer datasheet before releasing a production design.
A key design consideration is the distinction between maximum specification and a usable design margin. The 5.5 V supply limit should not be treated as a target operating point, and signals should not be expected to reach the physical supply rails under every load. Decoupling, grounding, feedback-component selection, output loading, and the chosen noise-gain network all affect achievable accuracy and stability.
This product page combines the exact orderable-part details, package information, application context, design guidance, and replacement constraints for OPA345UA. It also identifies which operating characteristics still require confirmation from the manufacturer datasheet, helping engineers move from general amplifier selection to a board-level design more efficiently.
Drop-in-Alternativen für OPA345UA – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.
OPA344UA
✅ Drop-In ⚠️ Spezifikationen ungeprüftPreis auf Anfrage
Datenblatt ansehen →OPA345UAG4
✅ Drop-In ⚠️ Spezifikationen ungeprüft📋 Referenzalternative (nicht im Katalog)
OPA345UA-Q1
✅ Drop-In ⚠️ Spezifikationen ungeprüft📋 Referenzalternative (nicht im Katalog)
OPA345UA Grenzwerte & elektrische Eigenschaften
| Amplifier Type | Single operational amplifier |
| Maximum Supply Voltage | 5.5 V |
| Minimum Supply Voltage | 2.5 V |
| Supply Configuration | Single supply |
| Gain-Bandwidth Product | 3 MHz |
| Input Common-Mode Range | Extends 300 mV beyond the supply rails |
| Input Rail-to-Rail | Rail-to-rail |
| Output Rail-to-Rail | Rail-to-rail |
| Device Class | General-purpose amplifier |
| Technology | CMOS |
| Series | MicroAmplifier |
| Gehäuse | 8-pin SOIC |
| Montageart | Surface mount |
OPA345UA 8-pin soic Pinbelegungsleitfaden
Pinbelegung für OPA345UA (8-pin soic-Gehäuse). Dieses analoge Bauteil verfügt über Eingangs-, Ausgangs- und Versorgungspins. Offset-Null-, Kompensations- und Enable-Pin-Konfigurationen entnehmen Sie dem Herstellerdatenblatt. Ideal für Signalaufbereitung und Verstärkerschaltungen.
Keine detaillierten Pinbelegungsdaten verfügbar für OPA345UA.
Siehe die Datenblatt für die vollständige Pin-Konfiguration.
Typische Anwendungen
OPA345UA ist geeignet für 6 Anwendungs: Low-Voltage Sensor Signal Conditioning, Portable Instrumentation Front End, Audio and Low-Level Analog Signal Paths, Data Acquisition and ADC Driver, Precision Active Filtering, Battery-Powered Analog Control.
Low-Voltage Sensor Signal Conditioning
OPA345UA fits a sensor-conditioning stage that operates from 2.5 V to 5.5 V and needs more usable input range than a conventional mid-supply amplifier. Its rail-to-rail input characteristic and approximately 300 mV common-mode extension beyond the supply rails help buffer sensor outputs that move close to either rail. The 3 MHz gain-bandwidth product permits useful closed-loop bandwidth in precision signal paths, although offset voltage, input bias current, and noise must be checked against the sensor impedance. A single amplifier keeps the channel compact, while the 8-pin SOIC package supports conventional surface-mount assembly. Choose external resistor and capacitor values from the intended gain, sensor source impedance, and noise-gain requirement, and verify the complete operating envelope using the manufacturer datasheet.
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Portable Instrumentation Front End
OPA345UA is suitable for portable instrumentation because it combines a single 2.5 V to 5.5 V supply architecture with rail-to-rail inputs and outputs in an 8-pin SOIC package. The approximately 300 mV input headroom beyond the rails can preserve common-mode operation in compact systems where the measured signal occupies much of the available voltage range. Its 3 MHz gain-bandwidth product is appropriate for conditioning moderate-bandwidth sensor signals rather than high-speed waveforms. The low-power single-amplifier format can simplify channel design and reduce board requirements, but battery lifetime still depends on the complete circuit load and operating duty cycle. Verify offset, noise, input impedance effects, and output-current requirements before selecting the gain network.
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Audio and Low-Level Analog Signal Paths
OPA345UA can be used in low-level audio and general analog paths when the system operates from a 2.5 V to 5.5 V single supply and requires rail-to-rail signal swing. Its single amplifier and 8-pin SOIC package allow it to serve as a preamplifier, unity-gain buffer, or active-filter element where one channel is sufficient. The 3 MHz gain-bandwidth product allows moderate-frequency amplification, while the approximately 300 mV input range beyond the rails increases usable signal headroom. Audio performance still depends on the selected feedback network, source impedance, load, and output configuration. Confirm noise density, total harmonic distortion, slew rate, and stability at the intended gain before using the device in a signal-quality-critical path.
Empfohlen
Data Acquisition and ADC Driver
OPA345UA is applicable to the buffer or gain stage ahead of an ADC in a low-voltage acquisition system. Rail-to-rail input and output operation can help preserve signal range when the converter and sensor share the same 2.5 V to 5.5 V supply domain. A 3 MHz amplifier bandwidth allows moderate-bandwidth acquisition signals to pass with useful closed-loop bandwidth, although ADC settling and acquisition time must be evaluated separately. Place the amplifier close to the ADC input, use a low-impedance reference plane, and keep feedback routing short to limit added noise and instability. Verify ADC input range, settling requirements, output-drive capability, and any anti-alias filter component values before finalizing the signal chain.
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Precision Active Filtering
OPA345UA is a candidate for precision low-voltage active filters because it provides rail-to-rail input and output behavior, a 3 MHz gain-bandwidth product, and operation from 2.5 V to 5.5 V. It can be configured as an inverting, non-inverting, or multi-feedback stage where the component count favors a single amplifier. The approximately 300 mV input headroom beyond the supply rails helps maintain common-mode range during filter operation, but stability and frequency response depend on the selected noise gain, resistor ratios, and capacitor tolerances. Simulate the complete closed-loop network and test tolerance, noise, settling, and output swing. Do not select passive component values solely from nominal gain-bandwidth product without accounting for parasitic capacitance.
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Battery-Powered Analog Control
OPA345UA fits battery-powered analog control loops that use a 2.5 V to 5.5 V single supply and benefit from rail-to-rail operation. The single-amplifier configuration avoids paying for unused channels, and the 8-pin SOIC footprint supports compact assembly. Its approximately 300 mV input range beyond the rails is useful when control signals are generated close to a supply limit, while the 3 MHz gain-bandwidth product covers many feedback-control bandwidths. Low system power depends on operating voltage, load current, bias current, and external-network values, so calculate the complete circuit budget rather than the amplifier alone. Confirm output drive, stability with capacitive loading, shutdown requirements, and the allowable tolerance of the control loop before production release.
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Zusammenfassung der empfohlenen Produkte
Technische Referenzdaten für OPA345UA – Vergleich, Designhinweise und Compliance-Informationen.
Auswahlhilfe
Vergleich mit Alternativen
| Parameter | Dieses Produkt | OPA344UA | OPA345UAG4 | OPA345UA-Q1 |
|---|---|---|---|---|
| Package | 8-pin SOIC | 8-pin SOIC, subject to confirmation | 8-pin SOIC, subject to confirmation | 8-pin SOIC, subject to confirmation |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Amplifier Count | 1 | 1 | 1 | 1 |
| Minimum Supply Voltage | 2.5 V | 2.5 V | 2.5 V | 2.5 V |
| Input and Output Type | Rail-to-rail input and output | Rail-to-rail input and output | Rail-to-rail input and output | Rail-to-rail input and output |
Wichtigste Unterscheidungsmerkmale
- Single 3 MHz amplifier in an 8-pin SOIC (vs. OPA344UA)
- Automotive-qualified family option (vs. OPA345UA)
- Low-voltage RRIO operation (vs. OPA345UAG4)
Designhinweise
Place the required bypass capacitor immediately adjacent to the OPA345UA supply and ground pins, and keep the connection loop short. The device's 3 MHz gain-bandwidth product can make stray capacitance around high-value feedback resistors relevant at higher closed-loop gains. Follow the manufacturer datasheet for capacitor values and pin assignments, and preserve a continuous ground reference beneath and around the amplifier rather than routing return current through signal traces.
Treat the 2.5 V minimum supply and 5.5 V maximum supply as operating boundaries rather than design targets. Rail-to-rail input operation extends approximately 300 mV beyond the rails, but output swing and input behavior still depend on frequency, load, temperature, and output voltage. Confirm the required signal amplitude against the datasheet's recommended operating conditions, especially when the sensor output or feedback node can approach a supply rail.
Do not select the feedback network from gain alone. Account for the amplifier's noise gain, source impedance, resistor and capacitor tolerances, output loading, and the frequency-dependent behavior of the 3 MHz gain-bandwidth product. Simulate the complete closed-loop circuit and check stability with realistic PCB capacitance. A rail-to-rail input does not mean unlimited input range, and a 5.5 V maximum supply does not authorize operation above that voltage.
Route the non-inverting input, inverting input, and feedback components to minimize coupling from switching nodes, display signals, and high-current return paths. Use a quiet analog ground strategy appropriate to the overall system and avoid sharing narrow return paths with motor, relay, or converter currents. Keep optional compensation components accessible during validation and consider probe loading when measuring gain, phase, and output settling.
Compliance-Informationen
The verified product information identifies OPA345UA as an active general-purpose amplifier but does not state RoHS, REACH, lead-free, halogen-free, conflict-minerals, or AEC-Q100 status. The base OPA345UA is not presented as an automotive-qualified part; confirm all compliance claims using the orderable-part documentation.