Texas Instruments OPA1S2385IDRCT

Overview

OPA1S2385IDRCT from Texas Instruments is a 250-MHz CMOS transimpedance amplifier (TIA) with integrated SPST switch and dual-channel buffer, designed for photodiode current-to-voltage conversion and fast sample-and-hold in optical networking. It delivers rail-to-rail I/O swing, 150 V/μs slew rate, 3 pA input bias current, and operates from +2.7 V to +5.5 V single supply - enabling burst-mode RSSI detection in GPON/EPON receivers.

For engineers reviewing the OPA1S2385IDRCT datasheet, OPA1S2385IDRCT pinout, OPA1S2385IDRCT application, or OPA1S2385IDRCT equivalent, this page provides verified functional specifications, validated pin roles, confirmed transimpedance and sample-and-hold use cases, and two technically documented alternative parts for low-voltage, high-bandwidth analog signal capture.

Technical Context

The OPA1S2385IDRCT integrates two FET-input op amps and a logic-controlled CMOS switch in a single SON-10 package: Channel A functions as a wideband transimpedance amplifier with 250-MHz small-signal bandwidth and 6 nV/√Hz voltage noise; Channel B serves as a rail-to-rail output buffer. The internal SPST switch features 4 Ω on-resistance, 1 pC charge injection, and active-low control (SC pin low closes switch).

Its architecture supports flexible configurations: transimpedance gain via external feedback resistor, external hold capacitor for sample-and-hold, and post-gain amplification. Input common-mode range extends 0.1 V beyond rails; output drives ±100 mA with 100 mV rail margin at 5.5 V supply - optimized for low-noise, high-speed photodiode monitoring and optical signal strength measurement.

Key Specifications

Pinout & Package

The OPA1S2385IDRCT is housed in a 3-mm × 3-mm SON-10 (DRC) package with wettable flanks, optimized for automated optical assembly and thermal performance (θJA = 46.2°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar transimpedance amplifier with integrated switch applications.

Compared with OPA1S2385IDRCT, OPA1S2384IDRCT offers identical performance with inverted switch logic - ideal for redesign reuse; LMH6629MF/NOPB trades integration for higher bandwidth but increases component count, layout risk, and power supply complexity.

Availability

OPA1S2385IDRCT is available at Aetrix Electronics and suitable for optical networking equipment, photodiode-based sensing systems, and high-speed sample-and-hold instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for OPA1S2385IDRCT 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 expertise in high-speed amplifiers and precision signal conditioning.

The OPA1S2385IDRCT belongs to TI's high-bandwidth, low-noise operational amplifier product line, engineered specifically for optical receiver front-ends, burst-mode signal acquisition, and compact analog signal capture in space-constrained, low-voltage systems.

FAQ

What is the switch control logic polarity for OPA1S2385IDRCT?

The OPA1S2385IDRCT features active-low switch control: applying a logic-low voltage to the SC pin closes the internal SPST switch (enabling track mode), while a logic-high opens it (enabling hold mode). This is the defining functional difference from the pin-compatible OPA1S2384IDRCT, which uses active-high control. The SC pin accepts standard 3.3 V or 5 V logic levels and draws less than 0.5 µA leakage current across temperature.

Can OPA1S2385IDRCT operate from a 3.3-V supply in photodiode TIA applications?

Yes, OPA1S2385IDRCT is fully specified for operation from +2.7 V to +5.5 V, including 3.3 V. At 3.3 V, it maintains 250-MHz small-signal bandwidth, 110 V/μs slew rate, and rail-to-rail output swing - making it ideal for low-voltage optical modules. Input common-mode range extends to (V–) – 0.1 V and (V+) + 0.1 V, allowing direct connection to biased photodiodes without level-shifting circuitry.

How does the OPA1S2385IDRCT minimize sampling error in hold mode?

The OPA1S2385IDRCT minimizes hold-mode sampling error through three key specifications: 1 pC typical charge injection limits voltage glitch on the hold capacitor; 4 Ω typical switch on-resistance reduces series resistance error during acquisition; and 10¹³ Ω input impedance on Channel B prevents capacitor discharge. Together, these ensure <1 mV error with a 1 nF hold capacitor and 1 µs hold time - verified in TI's SBOS645A characterization data.

What is the maximum photodiode capacitance supported by OPA1S2385IDRCT in transimpedance mode?

OPA1S2385IDRCT supports photodiode capacitances up to 10 pF in transimpedance configurations without external compensation, based on stability analysis in Figure 11 of SBOS645A. For higher capacitances (e.g., 15–20 pF), a small series resistor (10–20 Ω) between the photodiode anode and –IN A improves phase margin. The device's enhanced capacitive-load drive capability stems from its optimized output stage topology, not external compensation networks.

Does OPA1S2385IDRCT include thermal protection?

Yes, OPA1S2385IDRCT incorporates an on-chip thermal shutdown circuit that activates at +160°C junction temperature to prevent permanent damage. Operation resumes automatically when junction temperature falls below +140°C. The device's SON-10 package has θJA = 46.2°C/W, so at 9.2 mA quiescent current and 5.5 V supply, ambient temperature must remain ≤ +125°C to avoid triggering shutdown - well within its –40°C to +85°C specified operating range.