Texas Instruments OPA445ADDA

Overview

OPA445ADDA from Texas Instruments is a high-voltage, FET-input operational amplifier in an SO-8 PowerPAD package, rated for ±10V to ±45V supply operation, 15V/µs slew rate, and ±15mA output current. It delivers ±35V output swing into resistive loads and supports precision signal conditioning in test equipment and piezo drivers.

For engineers reviewing the OPA445ADDA datasheet, OPA445ADDA pinout, OPA445ADDA application, or OPA445ADDA equivalent, key selection criteria include its ±45V max supply rating, 10pA input bias current, SO-8 PowerPAD thermal performance (θ_JA = 52°C/W), −55°C to +125°C operating range, and offset trim capability on pins 1 and 5.

Technical Context

The OPA445ADDA uses JFET input stage architecture enabling ultra-low input bias current (±10pA typ) and high input impedance (10¹³ Ω differential). Its wide supply range (±10V to ±45V) and high slew rate (15V/µs) support large-signal, high-voltage applications without bandwidth collapse.

Laser-trimmed input circuitry ensures low input offset voltage (±1.5mV max over −25°C to +85°C) and drift (±10µV/°C). The SO-8 PowerPAD package provides dedicated thermal pad connected to V−, enabling junction-to-ambient thermal resistance of 52°C/W with 1in × 0.5in heat-spreader - critical for sustained high-voltage, high-current operation.

Key Specifications

Pinout & Package

OPA445ADDA is housed in an SO-8 PowerPAD package (package code DDA), featuring an exposed thermal pad on the underside electrically connected to V−. The package is pin-compatible with standard SO-8 footprints but requires soldering the thermal pad to a PCB copper area for thermal integrity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA445AU and OPA454IDDA, the OPA445ADDA uniquely balances high-voltage operation, trimmable offset, and thermally robust PowerPAD packaging - making it optimal for industrial test gear and piezo drivers where reliability under sustained load is non-negotiable.

Availability

OPA445ADDA is available at Aetrix Electronics and suitable for test equipment, high-voltage regulators, and piezo drivers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for OPA445ADDA 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 heritage in precision op amps and high-reliability industrial components.

The OPA445 product line was designed specifically for high-voltage, high-precision analog signal conditioning - targeting applications where supply headroom, thermal management, and DC accuracy intersect, such as automated test systems and motion control.

FAQ

What is the maximum continuous power supply voltage for the OPA445ADDA?

The OPA445ADDA supports a continuous operating supply voltage range of ±10V to ±45V (90V total), with absolute maximum ratings of ±50V. Operation beyond ±45V is not recommended for long-term reliability. The device maintains specified performance across this full range, including open-loop gain, slew rate, and output swing - verified from −25°C to +85°C and functional from −55°C to +125°C. Always use ≥0.1µF ceramic bypass capacitors rated for the full supply voltage on pins 2 and 5.

How does the SO-8 PowerPAD package of the OPA445ADDA improve thermal performance compared to standard SO-8?

The OPA445ADDA's SO-8 PowerPAD package features an exposed copper thermal pad on the bottom surface, electrically connected to V− (pin 5). When soldered to a 1in × 0.5in PCB copper area with five 13-mil vias, its junction-to-ambient thermal resistance drops to 52°C/W - versus 150°C/W for the standard SO-8 OPA445AU. This 65% reduction allows the OPA445ADDA to dissipate up to 1.93W continuously at +125°C junction temperature, enabling higher output current and longer duty cycles in high-voltage applications without external heatsinks.

Can the OPA445ADDA drive capacitive loads, and what is the recommended compensation method?

Yes, the OPA445ADDA can drive capacitive loads, but stability requires external compensation. For loads >100pF, TI recommends the RC-CC network shown in Figure 3 of the datasheet: a series resistor (RC ≈ 20Ω) and parallel capacitor (CC ≈ 0.22µF) between output and feedback node. This preserves phase margin while avoiding voltage drop across RC. The OPA445ADDA's internal compensation is optimized for gains ≥1 with resistive loads; un-compensated capacitive loading causes peaking or oscillation. Always verify stability with actual load and layout using step-response testing.

What is the purpose of pins 1 and 5 on the OPA445ADDA, and how should they be used?

Pins 1 and 5 on the OPA445ADDA are dedicated offset voltage trim terminals. They connect to opposite ends of a 100kΩ potentiometer (wiper to V−), forming a balanced bridge that nulls input differential pair mismatch. This adjustment corrects only the op amp's intrinsic offset - never system-level offsets - to avoid degrading temperature drift performance. Pin 1 is the negative trim terminal and pin 5 is the positive trim terminal; both must remain unconnected to any other circuit nodes. Do not tie either pin directly to supply rails or ground.

Is the OPA445ADDA pin-compatible with other OPA445 variants like the OPA445AP or OPA445BM?

The OPA445ADDA is pin-compatible with the OPA445AU (standard SO-8) and OPA445AP (DIP-8) in terms of signal and power pin assignments (pins 1–8 follow identical function mapping), but not with the TO-99 OPA445BM, which uses a different pinout and package geometry. While the SO-8 PowerPAD footprint matches standard SO-8 land patterns, the thermal pad (connected to V−) must be soldered to PCB copper - unlike the AU/AP variants. No PCB layout changes are needed for signal routing, but thermal pad layout and via placement are mandatory for OPA445ADDA functionality and reliability.