Texas Instruments OPA705UA

Overview

OPA705UA from Texas Instruments is a single-channel, rail-to-rail input/output CMOS operational amplifier optimized for low-power, medium-speed signal conditioning. It delivers 1MHz gain-bandwidth, 0.6V/µs slew rate, 0.5mV max input offset voltage, and 160µA quiescent current per amplifier, operating from ±2V to ±6V dual or 4V–12V single supply. It is used in portable sensor interfaces and transducer amplification where rail-swing headroom and battery efficiency are critical.

For engineers reviewing the OPA705UA datasheet, OPA705UA pinout, OPA705UA application, or OPA705UA equivalent, key selection criteria include its guaranteed rail-to-rail I/O swing (to within 40mV of rails at light load), ultra-low input bias current (1pA typ), CMRR up to 96dB in limited range, and SO-8 package compatibility with standard PCB footprints for space-constrained industrial and automotive subsystems.

Technical Context

The OPA705UA employs a complementary differential input stage-N-channel and P-channel pairs-to achieve rail-to-rail common-mode input range extending 300mV beyond both supply rails. Its class AB output stage enables rail-to-rail output swing while sustaining >100dB open-loop gain at 20kΩ load.

It is unity-gain stable and specified over –40°C to +85°C. Input protection diodes clamp signals exceeding supplies by >300mV, requiring external current limiting to ≤10mA; no phase inversion occurs under such conditions when current is properly limited.

Key Specifications

Pinout & Package

OPA705UA is housed in an 8-pin SOIC (SO-8) surface-mount package with JEDEC MS-012AC footprint, 1.27mm pitch, and RoHS-compliant NiPdAu lead finish. Thermal resistance θ_JA is 150°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA333AIDBVR and MCP6001T-E/OT, the OPA705UA uniquely balances rail-to-rail I/O, 1pA bias, and 160µA IQ across 4V–12V supplies-making it optimal for cost-sensitive, medium-precision analog front-ends where supply flexibility and sensor interface fidelity are jointly constrained.

Availability

OPA705UA is available at Aetrix Electronics and suitable for portable instrumentation, automotive cabin electronics, and industrial data acquisition systems requiring stable component supply, long-lifecycle availability, and RoHS-compliant SO-8 packaging.

Supply support for OPA705UA 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 delivering analog and embedded processing solutions, with deep expertise in precision amplifiers, data converters, and power management ICs.

The OPA705UA belongs to TI's OPA705 series of low-cost, rail-to-rail CMOS op amps designed specifically for battery-powered and space-constrained applications demanding wide supply range, low IQ, and robust input/output swing.

FAQ

What is the maximum capacitive load the OPA705UA can drive without oscillation?

The OPA705UA is characterized to drive up to 1000pF of pure capacitive load while maintaining stability. At unity gain, small-signal overshoot remains below 10% with 100pF load; for heavier loads, adding a 10Ω–20Ω series resistor inside the feedback loop (between output and inverting input) improves phase margin without affecting DC accuracy. This behavior is confirmed in the SBOS182A datasheet Figure "Small-Signal Overshoot vs Capacitive Load".

Does the OPA705UA support true rail-to-rail input beyond the supply rails?

Yes-the OPA705UA input common-mode voltage range extends 300mV beyond both V+ and V– rails at room temperature, enabled by its complementary N-channel/P-channel input stage. This allows direct connection to signals such as DAC outputs or reference voltages that exceed the op amp's own supply, provided input current is limited to ≤10mA via external series resistance, as specified in Absolute Maximum Ratings and Application Information sections of the SBOS182A datasheet.

What is the guaranteed output voltage swing for the OPA705UA at 20kΩ load?

At RL = 20kΩ and AOL > 100dB, the OPA705UA guarantees output swing to within 75mV of each supply rail. This is measured under specified conditions (VS = ±5V, TA = +25°C) and ensures ≥98.5% of full-scale dynamic range in 5V-supply systems. The value degrades to 150mV at 5kΩ load, as documented in the Electrical Characteristics table under "Voltage Output Swing from Rail".

Is the OPA705UA pin-compatible with other op amps in SO-8 packages like the LM358 or TL072?

No-the OPA705UA has two NC (no-connect) pins (6–8) and uses Pins 1–5 for –In, +In, Out, V–, and V+, unlike LM358 (dual, Pin 1 = Out A, Pin 2 = –In A, etc.) or TL072 (dual JFET, different pin mapping). Its SO-8 footprint matches mechanical dimensions but not functional pinout; direct replacement requires PCB redesign. Always verify pin functions against the OPA705UA-specific schematic in SBOS182A Section "Pin Configurations".

What is the operating temperature range qualified for the OPA705UA?

The OPA705UA is fully specified and guaranteed over the industrial temperature range of –40°C to +85°C. It also supports extended operation from –55°C to +125°C, though electrical parameters outside the –40°C to +85°C range are not tested or warranted. Storage temperature is rated from –65°C to +150°C, and junction temperature must not exceed +150°C, per Absolute Maximum Ratings in SBOS182A.