Texas Instruments OPA2846ID

Overview

OPA2846ID from Texas Instruments is a dual, wideband, low-noise, voltage-feedback operational amplifier optimized for high-dynamic-range signal conditioning. It delivers 300MHz closed-loop bandwidth at G = +10, 1.2nV/√Hz input voltage noise, 600V/µs slew rate, and −100dBc 2nd-harmonic distortion at 5MHz - enabling precision differential receivers in ultrasound and VDSL line interfaces.

For engineers reviewing the OPA2846ID datasheet, OPA2846ID pinout, OPA2846ID application, or OPA2846ID equivalent, this page provides verified specifications, SO-8 package terminal mapping, matched-channel performance data, and real-world design context for ADC preamplifiers, transimpedance amplifiers, and broadband differential receivers.

Technical Context

The OPA2846ID uses a decompensated voltage-feedback architecture with minimum stable gain of +7V/V, enabling high loop gain and ultra-low distortion at moderate gains. Its 1.65GHz gain-bandwidth product supports flat frequency response up to 100MHz at G = +10 with only 0.1dB peaking.

Each channel features matched AC/DC characteristics - including <±0.76mV input offset voltage, ±3.1V output swing into 100Ω, and −60dBc channel-to-channel crosstalk at 5MHz - making it suitable for I/Q signal paths and dual photodiode transimpedance front ends.

Key Specifications

Pinout & Package

OPA2846ID is housed in an SO-8 (D) package with exposed pad for thermal enhancement. Pin numbering follows standard TI SO-8 top-view convention (pin 1 = V+, pin 4 = V−, pin 5 = Out A, etc.).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar wideband, low-noise op amp applications.

Compared with OPA2843, OPA2846ID delivers 2× higher GBP and 0.8nV/√Hz lower noise - essential for >50MHz IF gain; versus OPA846, it offers matched-channel timing and crosstalk control at no penalty in AC performance, just doubled quiescent current.

Availability

OPA2846ID is available at Aetrix Electronics and suitable for high-speed data acquisition, medical ultrasound front ends, and broadband communications infrastructure requiring stable component supply across industrial temperature ranges.

Supply support for OPA2846ID 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 50 years of innovation in precision amplifiers and signal chain solutions.

The OPA2846ID belongs to TI's high-speed, low-noise op amp product line - engineered specifically for demanding applications including ADC driving, optical sensing, and wired communications receivers where dynamic range and fidelity are critical.

FAQ

What is the minimum stable gain for OPA2846ID, and why does it matter?

The OPA2846ID has a minimum stable gain of +7V/V. This reflects its decompensated voltage-feedback architecture, which prioritizes bandwidth and slew rate over unity-gain stability. Operating below G = +7 risks oscillation or excessive peaking; therefore, gain-setting resistors must satisfy RF/RG ≥ 6. For G = +10 designs, this is met with RF = 453Ω and RG = 50Ω as shown in Figure 1 of the SBOS274C datasheet. The OPA2846ID achieves 300MHz bandwidth only when this condition is respected.

Can OPA2846ID drive a 50Ω load directly, and what are the implications?

Yes, OPA2846ID can drive a 50Ω load, but output swing is reduced to ±2.9V (min) at +85°C, and harmonic distortion increases - e.g., 2nd-harmonic degrades from −100dBc (500Ω) to −66dBc (100Ω) at 5MHz. For optimal SFDR, TI recommends using a 100Ω load with external 50Ω termination at the measurement point, as implemented in Figure 1. This preserves both voltage headroom and distortion performance in test setups and production systems.

How does OPA2846ID compare to OPA846 in terms of channel matching and layout?

OPA2846ID provides tightly matched dual channels - with ≤0.02° differential phase and ≤0.02% differential gain error - due to monolithic integration and shared process control. OPA846 is single-channel, so achieving similar I/Q matching requires two separate die, introducing inter-device drift and layout-induced skew. For ultrasound beamforming or quadrature demodulation, OPA2846ID eliminates inter-channel calibration and reduces PCB area by 30% compared to dual OPA846 layouts.

What decoupling is required for OPA2846ID to maintain 300MHz bandwidth?

TI specifies 0.1µF ceramic + 6.8µF tantalum per supply rail, placed within 2mm of pins 1 (V+) and 8 (V−). The 0.1µF capacitor handles high-frequency noise (>10MHz), while the 6.8µF stabilizes mid-band ripple. Ground vias must connect both capacitors to a solid ground plane beneath the SO-8 footprint. Failure to follow this decoupling scheme causes peaking above 100MHz and measurable degradation in 2nd-harmonic distortion - confirmed in SBOS274C Figure 12 layout guidelines.

Is OPA2846ID suitable for transimpedance applications with >50pF photodiode capacitance?

Yes - the OPA2846ID's 1650MHz GBP supports two-stage transimpedance designs for large-area detectors. As shown in Figure 5 of SBOS274C, a 50pF diode capacitance can be accommodated using first-stage RF = 2.67kΩ and second-stage G = 37.5, achieving ~30MHz bandwidth. Critical to success is matching CF values to CD and GBP per Equation 5; for 50pF, CF ≈ 1.9pF is required. The OPA2846ID's low input capacitance (3.8pF total) minimizes added phase lag in such configurations.