Texas Instruments OPA820ID

Overview

OPA820ID from Texas Instruments is a unity-gain stable, low-noise voltage-feedback operational amplifier in an 8-pin SOIC package, delivering 240 MHz bandwidth at G = 2, 2.5 nV/√Hz input voltage noise, and ±110 mA output current. It operates from ±2.5 V to ±6 V or single 5 V to 12 V supplies and is optimized for ADC preamplifiers, video line drivers, and active filters requiring high speed with DC precision.

For engineers reviewing the OPA820ID datasheet, OPA820ID pinout, OPA820ID application, or OPA820ID equivalent, this page provides verified specifications, SOIC-8 pin functions, real-world use cases in composite video and data acquisition systems, and validated alternative parts for design flexibility and supply continuity.

Technical Context

The OPA820ID uses a voltage-feedback architecture with internal compensation enabling stable unity-gain operation while achieving >800 MHz small-signal bandwidth and <1 dB peaking. Its input stage combines bipolar and FET characteristics to achieve low input bias current (±17 µA typ) alongside ultra-low voltage noise (2.5 nV/√Hz).

It supports rail-compatible output swing-±3.7 V into no load and ±3.6 V into 100 Ω on ±5 V supplies-with minimal headroom requirements, making it suitable for driving mid-scale ADC inputs without rail-to-rail output circuitry. Differential gain/phase of 0.01%/0.03° confirms suitability for PAL/NTSC video signal conditioning.

Key Specifications

Pinout & Package

OPA820ID is packaged in an 8-pin SOIC (D package), 4.90 mm × 3.91 mm body size, with standard op amp pinout and no internal connections on pins 1, 5, and 8.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar voltage-feedback op amp applications.

Compared with OPA820ID, OPA2822ID offers dual-channel integration at modest noise trade-off, while OPA657U delivers extreme bandwidth at significantly higher noise and quiescent current - making OPA820ID optimal for balanced speed, noise, and power in precision analog front-ends.

Availability

OPA820ID is available at Aetrix Electronics and suitable for ADC preamplifier circuits, composite video line drivers, and active filter designs requiring stable component supply, consistent parametric performance, and long-term industrial temperature support (–40°C to +85°C).

Supply support for OPA820ID 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 company specializing in analog and embedded processing technologies, with leadership in high-performance op amps, data converters, and power management ICs.

The OPA820ID belongs to TI's high-speed precision op amp product line, engineered for applications demanding simultaneous wide bandwidth, low noise, and DC accuracy - particularly in test & measurement, imaging, and communications infrastructure.

FAQ

What supply voltages does the OPA820ID support?

The OPA820ID operates from dual supplies of ±2.5 V to ±6 V or a single supply of 5 V to 12 V. At ±5 V, it delivers ±3.6 V output swing into 100 Ω; at 5 V single supply, output swings from 1.2 V to 3.8 V (no load). These ranges allow direct interfacing with 14-bit ADCs like the ADS850 without level-shifting circuitry. The OPA820ID maintains specified AC and DC performance across its full operating temperature range (–40°C to +85°C).

Is the OPA820ID unity-gain stable, and what does that mean for my design?

Yes, the OPA820ID is internally compensated for unity-gain stability - no external compensation components are needed even when configured as a voltage follower (G = 1). This guarantees phase margin >45° and <1 dB peaking in small-signal response, eliminating oscillation risk in high-speed buffer applications. The OPA820ID achieves >800 MHz bandwidth at G = 1, making it suitable for wideband signal conditioning where stability and speed are both critical.

How does the OPA820ID perform in video applications?

The OPA820ID delivers 0.01% differential gain (dG) and 0.03° differential phase (dP) at PAL frequencies, meeting broadcast-grade video line driver requirements. Its 240 MHz bandwidth at G = 2 supports full NTSC/PAL baseband spectrum (0–5.5 MHz) with ample margin, while ±110 mA output current drives 75 Ω coaxial cables directly. The OPA820ID replaces legacy video op amps like the THS3001 without layout changes in SOIC-8 footprints.

Can the OPA820ID drive heavy capacitive loads?

The OPA820ID is sensitive to capacitive loading and may oscillate if directly driving >100 pF without isolation. TI recommends adding a series resistor (RS) between the output and capacitive load - e.g., 10 Ω for 100 pF, 47 Ω for 470 pF - as shown in Figure 15 of the OPA820ID datasheet. This RS network preserves stability while maintaining signal integrity. The OPA820ID's low 0.04 Ω closed-loop output impedance below 100 kHz ensures minimal gain error when combined with proper RS selection.

What are the thermal characteristics of the OPA820ID in SOIC-8 package?

In its 8-pin SOIC (D) package, the OPA820ID has a junction-to-ambient thermal resistance (RθJA) of 125°C/W and junction-to-board (RθJB) of 68.2°C/W. With 5.6 mA quiescent current at ±5 V, power dissipation is ~56 mW - resulting in <7°C junction rise above ambient under typical PCB conditions. The OPA820ID is fully specified over –40°C to +85°C ambient, and its thermal design supports reliable operation in enclosed industrial enclosures without forced airflow.