Texas Instruments OPA355UA

Overview

OPA355UA from Texas Instruments is a single-channel, high-speed CMOS operational amplifier optimized for video and wideband signal conditioning. It delivers 450 MHz unity-gain bandwidth, 200 MHz gain-bandwidth product, rail-to-rail output swing within 100 mV of rails, 5.8 nV/√Hz input voltage noise, and 3 pA input bias current - enabling precision, low-distortion amplification in 2.5 V to 5.5 V single-supply systems such as composite video buffers and photodiode transimpedance stages.

For engineers reviewing the OPA355UA datasheet, OPA355UA pinout, OPA355UA application, or OPA355UA equivalent, key selection considerations include its 100 ns enable time, 30 ns disable time, thermal shutdown protection at 160°C, differential gain/phase error (0.02%/0.05°), and support for high-speed ADC/DAC interface, optical networking, and ultrasound front-ends where bandwidth, noise, and power-down control are critical.

Technical Context

The OPA355UA employs a voltage-feedback CMOS architecture with unity-gain stability and Class AB output stage capable of ±60 mA continuous output current. Its input common-mode range extends 100 mV below ground and up to 1.5 V below V+, supporting true single-supply operation down to 2.5 V.

It integrates a digital enable function referenced to V– in split-supply mode or ground in single-supply mode, placing the output in high-impedance state during shutdown while drawing only 3.4 µA per channel. The internal thermal shutdown activates at 160°C junction temperature and resets at 140°C.

Key Specifications

Pinout & Package

OPA355UA is packaged in an 8-pin SOIC (D package) with 4.90 mm × 3.91 mm body size, rated for –40°C to +125°C operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed op amp applications.

Compared with OPA355UA, OPA356UA removes shutdown capability to reduce complexity and cost in always-on systems, while LMH6629MA trades integrated power control for raw bandwidth and noise performance - making OPA355UA the optimal choice for battery-powered, multiplexed, or thermally sensitive video and medical signal chains.

Availability

OPA355UA is available at Aetrix Electronics and suitable for video processing, ultrasound front-ends, and photodiode transimpedance amplifier designs requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for OPA355UA 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 90 years of innovation in high-performance signal chain solutions.

The OPAx355 product line was engineered specifically for high-fidelity, wideband analog signal conditioning in video, medical imaging, optical networking, and test equipment - prioritizing bandwidth, noise, distortion, and power-down control in compact packages.

FAQ

What is the minimum supply voltage required for stable operation of the OPA355UA?

The OPA355UA operates reliably from 2.5 V to 5.5 V total supply range, with recommended conditions specifying 2.7 V to 5.5 V. At 2.5 V, it maintains specified performance including rail-to-rail output swing and 450 MHz unity-gain bandwidth, though quiescent current drops slightly. Full electrical characteristics are guaranteed from 2.7 V per the datasheet's Recommended Operating Conditions table. Always verify thermal derating at low-VS high-load conditions in your OPA355UA design.

Does the OPA355UA support dual-supply operation, and how is the ENABLE pin referenced?

Yes, the OPA355UA supports dual supplies from ±1.25 V to ±2.75 V (2.5 V to 5.5 V total). In dual-supply mode, the ENABLE pin voltage threshold is referenced to V–, not ground - logic high is ≥2 V above V–, and logic low is ≤0.8 V above V–. This ensures correct enable/disable behavior regardless of supply configuration. The OPA355UA datasheet explicitly confirms this referencing scheme in Section 8.3.2.

What is the maximum capacitive load the OPA355UA can drive without instability, and what compensation is recommended?

The OPA355UA remains stable driving up to 100 pF with appropriate series resistance (RS): 80 Ω for 5.6 pF, 36 Ω for 47 pF, and 24 Ω for 100 pF loads (per Figure 15). Without RS, instability occurs beyond ~20 pF. For 150 Ω loads, the OPA355UA sustains 75 MHz 0.1-dB flatness. Always use the recommended RS values from the datasheet's "Recommended RS Values vs Capacitive Load" plot to maintain phase margin >45° in your OPA355UA layout.

How does thermal shutdown behave in the OPA355UA, and can it be disabled?

The OPA355UA features non-disableable, internal thermal shutdown that activates at 160°C junction temperature and resets automatically at 140°C. There is no user-accessible control or bypass. During shutdown, the output goes high-impedance and quiescent current drops to microamp levels. This protection is intrinsic to the die and cannot be overridden - ensuring robust reliability in overload, short-circuit, or poor heatsink scenarios involving the OPA355UA.

Is the OPA355UA pin-compatible with other members of the OPAx355 family, such as the OPA2355 or OPA3355?

No, the OPA355UA (SOIC-8) is not pin-compatible with the OPA2355 (VSSOP-10) or OPA3355 (SOIC-14/TSSOP-14). Each variant has distinct pin counts, functions, and layouts - e.g., OPA355UA has one ENABLE pin, while OPA2355 has separate ENABLE A/B pins. Pin compatibility exists only within same-channel-count variants sharing identical package types (e.g., OPA355DBVR in SOT-23-6 matches OPA355UA's functionality but not pinout). Always consult the specific device's Pin Configuration table before substituting any OPA355UA variant.