Texas Instruments OPA348AID

Overview

OPA348AID from Texas Instruments is a single-channel, rail-to-rail input/output CMOS operational amplifier optimized for low-power, single-supply applications. It delivers 1 MHz gain-bandwidth, 45 µA quiescent current, and 0.5 pA input bias current, enabling precision signal conditioning in battery-powered smoke alarms and CO detectors with supply voltages from 2.1 V to 5.5 V.

For engineers reviewing the OPA348AID datasheet, OPA348AID pinout, OPA348AID application, or OPA348AID equivalent, this page provides verified package mapping (SOIC-8), confirmed rail-to-rail I/O behavior, validated ADC driver performance per TI SBOS213H, and two documented alternative op amps with explicit functional and parametric distinctions.

Technical Context

The OPA348AID uses a complementary N/P-channel input stage to achieve rail-to-rail input operation extending 200 mV beyond both supply rails - enabling full-scale signal capture in 0–5 V systems. Its class AB output stage supports rail-to-rail swing within 18 mV of rails under light loads (100 kΩ) and maintains >90 dB open-loop gain at ±100 mV from rails into 5 kΩ.

Designed for unity-gain stability, it drives up to 250 pF capacitive loads directly and features 35 nV/√Hz input voltage noise density at 1 kHz, 10 µVPP 0.1–10 Hz noise, and 0.0023% THD+N at 1 kHz - making it suitable for high-impedance sensor buffering and precision ADC front-end conditioning.

Key Specifications

Pinout & Package

OPA348AID is packaged in an 8-pin SOIC (D package) with 4.90 mm × 3.91 mm body size and standard 1.27 mm pitch. Pin functions are electrically validated per TI SBOS213H Rev H.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar operational amplifier applications.

Compared with OPA333AIDR and MCP6001T-I/OT, OPA348AID uniquely combines rail-to-rail input beyond supplies, 0.5 pA bias current, and 45 µA IQ - making it the only option among the three qualified for direct 0–5 V ADC interface in space-constrained, battery-operated safety systems without external level-shifting components.

Availability

OPA348AID is available at Aetrix Electronics and suitable for smoke detector manufacturing, portable gas sensor modules, and medical pulse oximetry designs requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for OPA348AID includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, specializing in analog ICs, embedded processors, and high-reliability power management solutions.

The OPAx348 series was designed specifically for ultra-low-power, single-supply signal conditioning in safety-critical portable instrumentation - targeting applications where battery life, input impedance, and rail-to-rail dynamic range are simultaneously critical.

FAQ

What is the maximum capacitive load the OPA348AID can drive in unity-gain configuration?

The OPA348AID can directly drive up to 250 pF of pure capacitive load while maintaining stability and minimal overshoot in unity-gain buffer configuration. This capability is validated in TI SBOS213H Figure 13 and enables direct interfacing with ADC input capacitance (e.g., ADS7822) without external isolation resistors - preserving DC accuracy and settling time. For loads exceeding 250 pF, a 10–20 Ω series resistor at the output is recommended.

Does the OPA348AID support true rail-to-rail input beyond the supply rails?

Yes, the OPA348AID supports input voltages from (V−) − 0.2 V to (V+) + 0.2 V - a 200 mV extension beyond both supply rails. This is achieved via a complementary N/P-channel input stage, as detailed in SBOS213H section 7.3.2. It allows direct connection to 0–5 V signals in single-supply systems without external level-shifting, unlike many competing op amps limited to (V−) to (V+) input ranges.

What is the typical input bias current of the OPA348AID, and why does it matter for sensor interfaces?

The OPA348AID has a typical input bias current of 0.5 pA, specified over −40°C to +125°C. This ultra-low value prevents loading errors when interfacing with high-impedance sensors such as electret microphones, gas electrochemical cells, or photodiodes - ensuring signal fidelity and minimizing offset drift. In contrast, op amps with >10 pA IB would introduce measurable voltage errors across MΩ-level sensor impedances.

Can the OPA348AID operate from a 2.1 V supply, and what performance trade-offs occur?

Yes, the OPA348AID is fully specified and tested down to 2.1 V supply voltage per SBOS213H section 6.3. At 2.1 V, gain-bandwidth remains 1 MHz, quiescent current stays near 45 µA, and rail-to-rail input/output functionality is preserved. However, output swing into 5 kΩ loads reduces slightly (to ~125 mV from rails), and PSRR/CMRR decrease by ~10 dB - all within datasheet limits for battery-powered applications like smoke alarms.

How does the OPA348AID's noise performance compare to other low-power op amps in DC-coupled sensor applications?

The OPA348AID delivers 10 µVPP integrated noise (0.1–10 Hz) and 35 nV/√Hz voltage noise density at 1 kHz - superior to most sub-100 µA op amps. This low 1/f noise is critical for DC-coupled applications like CO detectors or medical sensors where baseline stability determines detection threshold accuracy. Its noise profile is explicitly characterized in SBOS213H Figure 17 and validated across temperature.