Texas Instruments OPA704UA/2K5

Overview

OPA704UA/2K5 from Texas Instruments is a single-channel, rail-to-rail input/output CMOS operational amplifier optimized for non-inverting gains ≥5, delivering 3MHz gain-bandwidth product and 3V/µs slew rate at 160µA quiescent current per amplifier. It operates from ±2V to ±6V dual supplies or 4V–12V single supply, with input swing extending 300mV beyond rails and output swing within 40mV of rails under light load - enabling high dynamic range in low-voltage sensor signal conditioning and portable data acquisition systems.

For engineers reviewing the OPA704UA/2K5 datasheet, OPA704UA/2K5 pinout, OPA704UA/2K5 application, or OPA704UA/2K5 equivalent, key selection criteria include its gain-stability requirement (G ≥ 5), rail-to-rail I/O performance at ultra-low power, and SOIC-8 package compatibility with legacy board layouts requiring minimal redesign for higher-speed analog front-ends.

Technical Context

The OPA704UA/2K5 employs a complementary input stage (N- and P-channel differential pairs) to achieve rail-to-rail input common-mode range, with a 500mV transition region where both pairs conduct - causing measurable variation in PSRR, CMRR, and offset voltage. Its class AB output stage uses common-source transistors to deliver rail-to-rail output swing into loads ≥1kΩ.

Unlike the unity-gain-stable OPA703 family, the OPA704 is internally compensated for closed-loop gains of 5 or greater, enabling higher bandwidth (3MHz vs. 1MHz) and faster settling (18µs @ 0.1% for G=5) without external compensation - but requiring explicit gain-setting resistors and feedback capacitor tuning (e.g., 3pF) for optimal step response.

Key Specifications

Pinout & Package

OPA704UA/2K5 is packaged in an 8-pin SOIC (SO-8) surface-mount package with standard pinout compatible with industry-wide op amp footprints.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar rail-to-rail, low-power op amp applications.

Compared with OPA704UA/2K5, OPA703UA/2K5 offers lower bandwidth but broader gain flexibility, while MCP6001T-E/OT trades ultra-low input bias and precision for lower cost and smaller size - making OPA704UA/2K5 the optimal choice for high-fidelity, medium-speed signal chains requiring G≥5 stability and sub-nA input leakage.

Availability

OPA704UA/2K5 is available at Aetrix Electronics and suitable for portable medical devices, automotive cabin sensors, industrial data acquisition modules, and wireless sensor nodes requiring stable component supply with guaranteed long-term availability.

Supply support for OPA704UA/2K5 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 leader specializing in analog and embedded processing technologies, with over 50 years of innovation in precision amplifiers and signal chain solutions.

The OPA704UA/2K5 belongs to TI's precision rail-to-rail CMOS op amp family, designed specifically for battery-powered and space-constrained applications demanding high dynamic range, ultra-low power, and robust DC accuracy across industrial temperature ranges.

FAQ

What is the minimum recommended gain for stable operation of the OPA704UA/2K5?

The OPA704UA/2K5 is internally compensated for closed-loop gains of 5 or greater. Operating at gains below 5 (e.g., unity-gain buffer) risks instability and peaking in frequency response. For G<5 applications, TI recommends the OPA703UA/2K5 instead. The OPA704UA/2K5 datasheet specifies all AC parameters - including 3MHz GBW and 3V/µs SR - only under G≥5 test conditions.

Can the OPA704UA/2K5 operate from a single 3.3V supply?

No - the OPA704UA/2K5 has a specified minimum single-supply voltage of 4V. At 3.3V, it falls outside guaranteed operating range and may exhibit degraded CMRR, reduced output swing, or failure to meet quiescent current or offset voltage specifications. For 3.3V systems, consider TI's OPA333 or OPA376 families, which are explicitly characterized down to 1.8V.

Does the OPA704UA/2K5 require external compensation capacitors in G=5 non-inverting configuration?

External compensation is not required for stability in G=5 non-inverting configuration, but a 3pF feedback capacitor (as shown in Figure 6 of the datasheet) is recommended to optimize step response and minimize overshoot when driving typical ADC input capacitances (e.g., 10–20pF). This capacitor improves settling time without affecting DC gain.

What is the maximum capacitive load the OPA704UA/2K5 can drive reliably?

The OPA704UA/2K5 can drive up to 1000pF of pure capacitive load while maintaining stability - but only when configured for gains ≥5. At G=5, the "Small-Signal Overshoot vs Capacitive Load" curve shows <10% overshoot at 1000pF. For unity-gain operation, TI recommends adding a 10Ω–20Ω series resistor inside the feedback loop (Figure 5) to restore stability with >100pF loads.

How does the input stage architecture of the OPA704UA/2K5 affect common-mode rejection?

The OPA704UA/2K5 uses a complementary input stage (N- and P-channel pairs) to achieve rail-to-rail common-mode range. However, in the 500mV transition region near mid-supply - where both pairs conduct - CMRR drops from 90dB (full-scale) to ~74dB. Designers should avoid placing critical common-mode signals in this region; for best CMRR, keep VCM > (V–) + 1.5V or < (V+) – 1.5V.