Texas Instruments OPA404KPG4

Overview

OPA404KPG4 from Texas Instruments (formerly Burr-Brown) is a quad high-speed precision dielectrically isolated FET (Difet®) operational amplifier in 14-pin PDIP package. It delivers 6.4 MHz gain bandwidth, 35 V/µs slew rate, ±750 µV max input offset voltage, ±4 pA max input bias current, and 1.5 µs settling time to 0.01%, enabling high-accuracy signal conditioning in low-leakage, wide-bandwidth analog front-ends for medical ultrasound and precision instrumentation.

For engineers reviewing the OPA404KPG4 datasheet, OPA404KPG4 pinout, OPA404KPG4 application, or OPA404KPG4 equivalent, key selection considerations include its cascode-input architecture for stable bias current vs. common-mode voltage, laser-trimmed thin-film resistors for low offset drift, unity-gain stability, and standard quad DIP pinout for drop-in upgrades of legacy BIFET amplifiers.

Technical Context

The OPA404KPG4 employs a dielectrically isolated FET (Difet®) input stage with cascode topology, decoupling gate-to-drain voltage variations to maintain ultra-low bias current (<±4 pA) across ±10.5 V common-mode range. Its internal compensation ensures unity-gain stability without external components.

It integrates four independent amplifiers sharing a single ±15 V supply, each featuring 88–100 dB open-loop gain, 125 dB channel separation at 100 Hz, and 10¹³ Ω || 1 pF differential input impedance - optimized for high-Z sensor interfaces and low-distortion signal chains where leakage and noise must be minimized.

Key Specifications

Pinout & Package

OPA404KPG4 is housed in a 14-pin plastic dual in-line package (PDIP), compliant with JEDEC MS-001, with 0.3-inch body width and 0.1-inch lead pitch. Thermal resistance θ_JA = 120°C/W enables operation up to +85°C ambient with minimal derating.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad precision op amp applications.

Compared with OPA404KPG4, OPA4134UA trades ultra-low bias current for improved audio linearity, while LMC6084IMX sacrifices bandwidth and slew rate to achieve rail-to-rail operation and femtoamp bias - making OPA404KPG4 uniquely suited for high-speed, high-impedance precision analog signal chains.

Availability

OPA404KPG4 is available at Aetrix Electronics and suitable for precision instrumentation, medical ultrasound systems, and professional audio equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for OPA404KPG4 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 acquired Burr-Brown in 2000 and maintains its precision analog portfolio, emphasizing high-performance op amps, data converters, and interface ICs for industrial, medical, and test equipment markets.

The OPA404KPG4 belongs to TI's legacy Difet® precision op amp family, engineered specifically for applications demanding simultaneous low input bias current, wide bandwidth, and low offset - such as photodiode amplifiers and high-resolution sensor signal conditioning.

FAQ

What is the maximum operating temperature for the OPA404KPG4?

The OPA404KPG4 is specified for operation from –25°C to +85°C ambient temperature. Its ceramic DIP variants (e.g., OPA404AG) extend to –55°C to +125°C, but the KPG4 suffix denotes the plastic DIP version with the 0°C to +70°C specification range per ordering documentation. Derating applies above +70°C based on θ_JA = 120°C/W.

Does the OPA404KPG4 require external compensation for unity-gain stability?

No, the OPA404KPG4 is internally compensated and unity-gain stable. It drives capacitive loads up to 1000 pF in gain = +1 configuration without oscillation, as confirmed in the "Load Capacitance Stability" specification (1000 pF). No external compensation network is needed for standard buffer or follower applications.

Can the OPA404KPG4 be used with single-supply operation?

The OPA404KPG4 is designed for dual-supply operation (±5 V to ±18 V) and does not support true rail-to-rail input or output. Its common-mode input range is ±10.5 V, and output swing is ±11.5 V into 2 kΩ - limiting usable headroom on single supplies. For single-supply designs, consider TI's LMC6084 or OPA333 families instead.

How does the cascode input stage of the OPA404KPG4 improve performance over standard BIFET op amps?

The cascode input stage in the OPA404KPG4 isolates the FET gate from drain voltage variations, preventing bias current increase with common-mode voltage - a known limitation in BIFET amplifiers like LF156. This yields stable ±4 pA bias current across ±10.5 V CM range, critical for high-precision integrators and photodiode circuits.

Is the OPA404KPG4 pin-compatible with the LM324 or TL074?

Yes, the OPA404KPG4 uses the industry-standard 14-pin quad op amp pinout (per Figure "G" DIP package), matching LM324, TL074, and OP-15/16/17. This allows direct PCB-level replacement in existing designs - provided supply voltage (±15 V typical) and thermal layout accommodate its 10 mA quiescent current and 120°C/W θ_JA.