onsemi FOD8173TR2

Overview

FOD8173TR2 from onsemi is a high-speed logic gate optocoupler featuring an AlGaAs LED input stage and a CMOS detector IC with integrated photodiode, transimpedance amplifier, and totem-pole output driver. It delivers 20 Mbit/sec NRZ data rate, 55 ns max propagation delay, and operates across 3.0–5.5 V supply and −40 °C to +100 °C, enabling robust digital isolation in industrial bus interfaces and microprocessor I/O.

For engineers reviewing the FOD8173TR2 datasheet, pinout, applications, or equivalent options, this device is selected for high-noise environments requiring guaranteed CMTI ≥20 kV/μs, UL1577-rated 5,000 V_ACRMS isolation, and compatibility with both 3.3 V and 5 V CMOS logic levels.

Technical Context

The FOD8173TR2 implements galvanic signal isolation via monolithic integration of an AlGaAs LED and a high-speed CMOS receiver - eliminating external biasing or level-shifting components. Its internal transimpedance amplifier and voltage comparator enable deterministic switching with pulse width distortion ≤20 ns and rise/fall times ≤7 ns under 15 pF load.

This optocoupler supports bidirectional logic-level translation across isolated domains without polarity inversion, as confirmed by its truth table (LED off → VO high; LED on → VO low). It meets DIN EN/IEC 60747-5-5 requirements for reinforced insulation when ordered with the "V" suffix variant, though FOD8173TR2 itself is the wide-lead stretched SOIC-6 tape-and-reel version without certified VIORM = 1,140 V_peak.

Key Specifications

Pinout & Package

Package: Stretched Body SOP-6 (Wide Lead), Case 751EM - 5.3 mm body width, 7.5 mm length, 2.3 mm height, 1.27 mm pitch; RoHS-compliant, Pb-free reflow compatible per JEDEC J-STD-020.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed logic gate optocoupler applications.

Compared with Si8710BC-B-IS and HCPL-0723, the FOD8173TR2 offers the highest certified isolation voltage (5,000 V_ACRMS) and widest operating temperature range, making it preferred for industrial motor control and grid-tied inverters where reliability under sustained thermal stress and high-voltage transients is non-negotiable.

Availability

FOD8173TR2 is available at Aetrix Electronics and suitable for industrial field bus communications, programmable logic controller I/O, and isolated microprocessor system interfaces requiring stable component supply and long-term lifecycle support.

Supply support for FOD8173TR2 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier focused on energy-efficient innovation for automotive, industrial, cloud, and IoT applications.

The FOD8173TR2 belongs to onsemi's high-speed logic gate optocoupler product line, engineered specifically for noise-immune digital isolation in harsh industrial environments with demanding timing and safety requirements.

FAQ

What is the maximum recommended forward current for the LED input of the FOD8173TR2?

The absolute maximum average forward input current for the FOD8173TR2 is 20 mA, with a recommended operating range of 5.0–16 mA for reliable threshold detection. Exceeding 20 mA risks accelerated LED degradation and reduced lifetime; design should include a series current-limiting resistor calculated using VF ≈ 1.35 V at IF = 10 mA. The FOD8173TR2 datasheet specifies no derating required up to +100 °C ambient.

Does the FOD8173TR2 require an external bypass capacitor, and where is it placed?

Yes, the FOD8173TR2 requires a 0.1 µF ceramic bypass capacitor connected between Pin 4 (V_DD) and Pin 6 (GND) on the output side to suppress supply noise and ensure stable CMOS output switching. This is explicitly mandated in the datasheet (Note 2, Table 4) and omission causes increased propagation delay variation and potential output oscillation under dynamic load conditions. The FOD8173TR2's internal totem-pole driver draws transient current that must be locally sourced.

Can the FOD8173TR2 operate with a 2.5 V supply on the output side?

No, the FOD8173TR2 is not specified for 2.5 V operation: its recommended V_DD range is strictly 3.0 V to 5.5 V, and electrical characteristics (e.g., VOL ≤ 0.8 V, VOH ≥ V_DD − 0.5 V) are only guaranteed within that window. At 2.5 V, the CMOS output stage may fail to meet logic thresholds, and propagation delay increases beyond 55 ns. The FOD8173TR2 must be used with either 3.3 V or 5 V supplies per its qualification scope.

What is the meaning of "TR2" in the part number FOD8173TR2?

The "TR2" suffix in FOD8173TR2 denotes tape-and-reel packaging with 1,000 units per reel and wide-lead stretched SOIC-6 (Case 751EM) construction. It distinguishes this variant from tube-packaged versions (e.g., FOD8173T) and discontinued tape variants (e.g., FOD8173R2). The FOD8173TR2 does not include the "V" suffix, so it lacks the pending DIN EN/IEC 60747-5-5 certification - its VIORM remains 891 V_peak, not 1,140 V_peak.

How does the FOD8173TR2 handle common-mode transients, and what is its CMTI rating?

The FOD8173TR2 achieves ≥20 kV/μs common-mode transient immunity (CMTI) at both output high and low states, verified per IEC 60747-5-5 test conditions (V_CM = 1000 V step, dV/dt applied to isolation barrier). This ensures reliable operation in noisy environments like variable-frequency drives, where rapid ground potential shifts would otherwise corrupt digital signals. The FOD8173TR2's internal CMOS detector architecture inherently rejects such transients without external filtering.