Texas Instruments OPA705NA/250

Overview

OPA705NA/250 from Texas Instruments is a single-channel, rail-to-rail input/output CMOS operational amplifier optimized for low-power, precision signal conditioning in space-constrained systems. It delivers 1MHz gain-bandwidth, 0.6V/µs slew rate, ±0.5mV max input offset voltage, and operates from 4V to 12V single supply or ±2V to ±6V dual supply - enabling use in automotive sensor interfaces and portable data acquisition front-ends.

For engineers reviewing the OPA705NA/250 datasheet, OPA705NA/250 pinout, OPA705NA/250 application, or OPA705NA/250 equivalent, key selection criteria include its 160µA quiescent current per amplifier, 1pA input bias current, 40mV output swing from rail (RL = 100kΩ), rail-to-rail common-mode input range extending 300mV beyond supplies, and guaranteed operation from –40°C to +85°C in SOT23-5 packaging.

Technical Context

The OPA705NA/250 employs a complementary N/P-channel input stage to achieve rail-to-rail input operation, with a 500mV transition region where both pairs conduct - causing measurable variation in PSRR, CMRR, and THD within that zone. Its class AB common-source output stage enables 40mV rail-to-rail swing into high-impedance loads while sustaining >100dB open-loop gain at 75mV from rails (RL = 20kΩ).

This device is unity-gain stable and specified across full supply (±2V to ±6V) and temperature (–40°C to +85°C) ranges. Input protection diodes clamp signals to V+ and V– rails ±0.3V, permitting safe overvoltage handling up to 10mA input current - critical for transducer amplifier and test equipment applications exposed to transient signals.

Key Specifications

Pinout & Package

SOT23-5 surface-mount package (DBV drawing), 2.9mm × 1.6mm footprint, 1.0mm height, moisture sensitivity level 2 (260°C peak reflow), RoHS-compliant with NiPdAu lead finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA333AIDBVR and MCP6001UT-E/OT, the OPA705NA/250 uniquely balances rail-to-rail input/output capability, 1pA bias current, and sub-200µA quiescent power - making it optimal for transducer amplifiers where input voltage range and power efficiency jointly constrain design.

Availability

OPA705NA/250 is available at Aetrix Electronics and suitable for automotive sensor interfaces, portable data acquisition systems, and active filter stages requiring stable component supply with guaranteed long-term availability.

Supply support for OPA705NA/250 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 decades of expertise in precision amplifiers and signal chain solutions.

The OPA705NA/250 belongs to TI's OPA705 series of low-cost, rail-to-rail CMOS op amps designed specifically for cost-sensitive, low-power applications demanding wide supply range and high input impedance - such as automotive body electronics and portable instrumentation.

FAQ

What is the maximum capacitive load the OPA705NA/250 can drive without oscillation?

The OPA705NA/250 can drive up to 1000pF of pure capacitive load while maintaining stability. For unity-gain configurations with >100pF loads, TI recommends inserting a 10Ω–20Ω series resistor between the output and feedback network to suppress ringing - a technique validated in the SBOS182A datasheet Figure 5. This preserves DC accuracy while improving transient response.

Does the OPA705NA/250 exhibit phase inversion when input voltages exceed the supply rails?

No, the OPA705NA/250 does not exhibit phase inversion when inputs exceed the supply rails, provided input current is limited to ≤10mA - a condition easily met using a series current-limiting resistor. This behavior is confirmed in SBOS182A Figure 4 and enables safe interfacing with overvoltage-prone sensors like thermocouples or unconditioned transducer outputs.

What is the minimum supply voltage required for guaranteed operation of the OPA705NA/250?

The OPA705NA/250 is fully specified and guaranteed over a single-supply range of 4V to 12V (or ±2V to ±6V dual supply). While absolute maximum ratings allow down to 3.6V, the electrical characteristics table explicitly defines performance only from 4V - so 4V is the minimum for guaranteed spec compliance across –40°C to +85°C.

Can the OPA705NA/250 be used in a dual-supply configuration with asymmetric rails?

Yes, the OPA705NA/250 supports asymmetric dual supplies (e.g., +5V and –3V) as long as the total supply voltage (V+ – V–) remains within 4V to 12V and each rail stays within absolute maximum ratings (V– ≥ –0.3V relative to ground, V+ ≤ 13.2V). However, common-mode and output swing limits scale with the actual rail values - verify VCM and VO constraints per SBOS182A Section 6.3.

How does the OPA705NA/250's input stage architecture affect CMRR performance?

The OPA705NA/250 uses a complementary N/P-channel input stage, creating a 500mV transition region near mid-supply where both pairs conduct. Within this region, CMRR degrades from 96dB (limited range) to 66dB - a documented trade-off for rail-to-rail input. Designers should avoid placing critical common-mode signals in this zone or use external filtering to mitigate its impact on precision measurements.