Texas Instruments OPA380AIDG4

Overview

OPA380AIDG4 from Texas Instruments is a precision transimpedance amplifier optimized for photodiode current-to-voltage conversion, featuring 90MHz gain bandwidth, 25µV max offset voltage, 0.1µV/°C max drift, 50pA max input bias current, and 1MHz transimpedance bandwidth in typical configurations. It operates from 2.7V to 5.5V and delivers 4–5 decades of dynamic range (1nA to 100µA) in single-stage I/V conversion for optical front-ends.

For engineers reviewing the OPA380AIDG4 datasheet, OPA380AIDG4 pinout, OPA380AIDG4 application, or OPA380AIDG4 equivalent, key selection criteria include transimpedance stability with photodiode capacitance, output swing to 0V via external pulldown resistor, low 1/f noise for precision DC-coupled sensing, and guaranteed performance across −40°C to +125°C.

Technical Context

The OPA380AIDG4 uses an auto-zero architecture with a time-continuous 90MHz signal-path amplifier, zero-corrected every 100µs, enabling excellent long-term VOS stability (<1µV drift in 300-hour life test) and minimal 1/f noise. Its internal overload recovery circuit ensures 100ns return-to-linear operation after positive-rail saturation.

Designed specifically for inverting transimpedance configurations, it accepts photodiode current at the inverting input while holding the noninverting input at a fixed bias voltage. Input common-mode range extends from V− to (V+) − 1.8V, and output swing reaches within 100mV of V− (or to 0V with −5V pulldown resistor) and 600mV of V+ under 2kΩ load.

Key Specifications

Pinout & Package

OPA380AIDG4 is packaged in MSOP-8 (8-pin Mini Small Outline Package), with exposed thermal pad for enhanced thermal dissipation in high-density layouts. Pin 1 is marked with a dot; device is not pin-compatible with SO-8 due to different footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA380AIDG4, OPA300IDBVR trades long-term stability and low bias current for higher bandwidth, while OPA335AIDBVR sacrifices speed for ultra-low offset and zero-drift behavior-neither offers the balanced 90MHz GBW, 25µV VOS, and 50pA IB combination unique to OPA380AIDG4.

Availability

OPA380AIDG4 is available at Aetrix Electronics and suitable for photodiode monitoring, precision I/V conversion, and CAT-scanner front-end designs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for OPA380AIDG4 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 broad portfolio coverage in precision amplifiers, data converters, and signal chain solutions.

The OPA380AIDG4 belongs to TI's precision transimpedance amplifier product line, engineered specifically for high-speed, low-noise optical current sensing in medical imaging, industrial inspection, and fiber-optic communications.

FAQ

What is the maximum transimpedance bandwidth achievable with OPA380AIDG4?

The OPA380AIDG4 achieves >1MHz transimpedance bandwidth in most configurations, as confirmed by its 90MHz gain-bandwidth product and design optimization for photodiode capacitance (e.g., 10–100pF). Bandwidth depends on feedback resistor (RF) and total input capacitance (CTOT); for example, with RF = 10MΩ and CTOT = 10pF, f₃dB ≈ 90MHz / (2 × π × RF × CTOT) ≈ 1.4MHz. The datasheet explicitly states "transimpedance bandwidth of >1MHz" as a key feature of OPA380AIDG4.

Does OPA380AIDG4 support true 0V output swing on single supply?

Yes, OPA380AIDG4 supports true 0V output swing using an external pulldown resistor (e.g., 2kΩ) connected between VOUT and a −5V supply, as detailed in Figure 3 and the "Achieving Output Swing to Ground" section. Without this resistor, output swings to within 100mV of V− (ground); with it, linear operation extends to 0V across −40°C to +125°C. This capability is a defined feature of OPA380AIDG4-not inferred or approximate.

What is the input bias current specification for OPA380AIDG4, and why does it matter?

OPA380AIDG4 has a maximum input bias current of ±50pA at +25°C, with typical values near ±3pA. This ultra-low IB minimizes voltage error across high-value feedback resistors (e.g., 10MΩ), where even 50pA creates 500µV offset-critical for nA-level photocurrent accuracy. The specification is validated across temperature and forms part of OPA380AIDG4's precision photodiode interface capability.

How does the auto-zero architecture of OPA380AIDG4 improve long-term stability?

OPA380AIDG4 uses an auto-zero topology that corrects input offset every 100µs using internal sampling, resulting in <1µV long-term VOS variation (per 300-hour life test at 150°C). This eliminates 1/f noise and drift mechanisms inherent in conventional op amps, directly enabling stable calibration in optical sensors where recalibration intervals must exceed years-confirmed in the OPA380AIDG4 datasheet Section 9.

Is OPA380AIDG4 compatible with MSOP-8 PCB footprints used for other TI amplifiers?

OPA380AIDG4 uses the standard TI MSOP-8 package (JEDEC MO-187AA), with 0.65mm pitch and identical mechanical dimensions to OPA2380AIDGKR and OPA350AIDBVR. However, pin functions differ: OPA380AIDG4 has three NC pins (1,4,5), whereas dual variants allocate those pins to second amplifier channels. Layout reuse is possible only if NC pins are unconnected and thermal pad soldering matches-verified in TI's SBOS291G package drawing.