Texas Instruments OPA1671IDCKR

Overview

OPA1671IDCKR from Texas Instruments is a rail-to-rail input/output, low-noise audio operational amplifier optimized for electret microphone preamplification and high-fidelity signal conditioning. It delivers 4.0 nV/√Hz voltage noise at 10 kHz, –109 dB THD+N at 1 kHz, and 13 MHz gain-bandwidth product while operating from 1.7 V to 5.5 V supply - enabling high dynamic range in portable audio interfaces and sensor front-ends.

For engineers reviewing the OPA1671IDCKR datasheet, OPA1671IDCKR pinout, OPA1671IDCKR application, or OPA1671IDCKR equivalent, key selection criteria include its ultra-low 10 pA input bias current, 6 pF differential input capacitance, rail-to-rail operation down to 1.7 V, and SC-70 package suitability for space-constrained PCB layouts in consumer and industrial audio systems.

Technical Context

The OPA1671IDCKR employs a complementary N/P-channel input stage enabling true rail-to-rail common-mode input range (V– to V+), with seamless transition between input pairs across the full supply. Its class-AB output stage supports 5 V/µs slew rate and drives ≥10 kΩ loads while maintaining stability in unity-gain configuration.

Internal EMI rejection filtering (–3 dB at ~20 MHz) suppresses RF rectification effects from GSM, Bluetooth, and Wi-Fi bands, and its low 4.7 fA/√Hz current noise ensures minimal contribution in high-impedance microphone and transducer applications where source resistance dominates total noise.

Key Specifications

Pinout & Package

OPA1671IDCKR is packaged in a 5-pin SC-70 (DCK) case measuring 2.00 mm × 1.25 mm, optimized for high-density portable PCBs. The package features gull-wing leads compatible with standard reflow processes and provides thermal resistance of 214.7°C/W (junction-to-ambient).

Key Features

Applications

Equivalent & Alternatives

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

Compared with OPA1672IDGKR and OPA1611AIDR, the OPA1671IDCKR uniquely balances ultra-low noise, single-supply rail-to-rail operation, integrated EMI filtering, and SC-70 footprint - making it optimal for space- and power-constrained portable audio front-ends where RF immunity and 1.7 V minimum supply are mandatory.

Availability

OPA1671IDCKR is available at Aetrix Electronics and suitable for electret microphone preamplifiers, auxiliary line input buffers, and active filter circuits requiring stable component supply across consumer electronics, industrial HMI, and automotive infotainment programs.

Supply support for OPA1671IDCKR 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 precision amplifiers, data converters, and power management ICs.

The OPA1671 belongs to TI's high-performance audio op amp portfolio, designed specifically for low-noise, low-distortion signal conditioning in portable, battery-powered, and EMI-prone environments - emphasizing rail-to-rail operation, wide bandwidth, and robust RF immunity.

FAQ

What is the maximum capacitive load the OPA1671IDCKR can drive without oscillation?

The OPA1671IDCKR remains stable with ≤100 pF capacitive load in unity-gain configuration. For heavier loads (e.g., >100 pF cable capacitance), a 20–50 Ω isolation resistor must be placed in series with the output. This is confirmed by Figure 21 in the SBOS931B datasheet, which shows overshoot increases beyond 100 pF unless R_ISO ≥ 24.9 Ω. Always verify stability with actual board parasitics using bench testing.

Does the OPA1671IDCKR support single-supply operation at 3.3 V?

Yes, the OPA1671IDCKR fully supports 3.3 V single-supply operation. Its specified supply range is 1.7 V to 5.5 V, and all key parameters - including rail-to-rail input/output swing, 4.0 nV/√Hz noise, and –109 dB THD+N - are guaranteed across this range at –40°C to +125°C. At 3.3 V, output swing reaches within 20 mV of each rail under 10 kΩ load.

How does the internal EMI filter in the OPA1671IDCKR improve system-level RF immunity?

The OPA1671IDCKR integrates a 20-MHz cutoff low-pass filter on both inputs, suppressing rectification of common RF bands: 30 dB rejection at 400 MHz, 60 dB at 1.8 GHz, and 100 dB at 5 GHz. This eliminates need for external ferrite beads or RC filters in microphone preamps exposed to cellular/Wi-Fi radiation - verified by EMIRR test data in Section 7.3.4 of SBOS931B.

Can the OPA1671IDCKR be used in a transimpedance amplifier for photodiode sensing?

Yes, the OPA1671IDCKR is well-suited for transimpedance amplifiers due to its 10 pA input bias current, 6 pF differential input capacitance, and 13 MHz GBW. These specs minimize dark-current error and allow stable operation with feedback resistors up to 10 MΩ and photodiode capacitances ≤50 pF - as validated in TI Precision Labs training modules and application note SBOA279.

What is the recommended power supply decoupling for the OPA1671IDCKR in SC-70 package?

Place a 100 nF X7R ceramic capacitor between V+ (Pin 5) and V– (Pin 2), located ≤2 mm from the OPA1671IDCKR pins. Add a 1 µF tantalum or ceramic bulk capacitor near the board's local 3.3 V or 5 V rail. Avoid shared vias - use dedicated thermal pads and short traces. This decoupling scheme is validated in Layout Example (Figure 10) of SBOS931B and prevents supply-induced oscillation at high frequencies.