Infineon Technologies SFH350V

Overview

SFH350V from Infineon Technologies is a plastic fiber optic phototransistor detector with molded microlens, 2.2 mm aperture for standard 1000 µm plastic fiber coupling, 850 nm peak spectral sensitivity, 0.8 mA photo current at 5 V and 10 µW optical input (660 nm), and –40°C to +85°C operating temperature range - used in light barriers and household electronics for galvanically isolated signal detection.

For engineers reviewing the SFH350V datasheet, SFH350V pinout, SFH350V application, or SFH350V equivalent, key selection criteria include spectral response (400–1100 nm), dark current ≤1 nA (VR = 20 V), rise/fall time of 20 µs (RL = 1 kΩ), current gain HFE = 500, and thermal coefficient of photo current (0.34–0.66 %/K across λ).

Technical Context

This phototransistor operates in common-emitter configuration with base left unconnected (photodiode-driven base region), delivering linear photocurrent output proportional to coupled optical power from plastic fiber. Its molded microlens enhances coupling efficiency into the 2.2 mm aperture without requiring fiber stripping.

It exhibits low capacitance (CCE = 10.5 pF, CCB = 21.5 pF) and stable gain over temperature (TCHFE = 0.55 %/K), enabling reliable operation in ambient temperatures up to +85°C and compatibility with wave soldering (260°C, 5 s).

Key Specifications

Pinout & Package

Package: Plastic TO-style housing with integrated connector for 1000 µm plastic fiber; mounting screw included; wave-solderable; supplied in tubes.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar phototransistor-based optical detection applications.

Compared with SFH350V, TEFT4300 offers lower integration but broader availability, while VEMD2020X01 trades fiber compatibility for SMD manufacturability - choice depends on whether plastic fiber coupling and molded lens are mandatory system requirements.

Availability

SFH350V is available at Aetrix Electronics and suitable for optical light barriers, household appliance safety interlocks, and power electronics feedback isolation requiring stable component supply across extended temperature ranges and long-lifecycle production.

Supply support for SFH350V 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

Infineon Technologies AG is a German semiconductor manufacturer specializing in power management, automotive, industrial, and sensor solutions, with global manufacturing and quality certification to ISO 9001 and IATF 16949.

SFH350V belongs to Infineon's legacy SFH fiber-optic component family, designed specifically for robust, low-cost galvanic isolation in consumer and industrial electro-mechanical interfaces using plastic optical fiber.

FAQ

What is the maximum optical input power the SFH350V can handle without saturation or damage?

SFH350V has no specified absolute optical damage threshold, but its linear photocurrent response holds up to ≥1 mA (per datasheet IC max = 50 mA, though typical operation stays below 1 mA). At VCE = 5 V and RL = 1 kΩ, saturation begins near 4–5 V collector swing - design must limit optical input to maintain VCE > 0.5 V. Thermal limits (PTOT = 200 mW) are not reached under normal photodiode-driven operation.

Can the SFH350V be used with glass fiber instead of plastic fiber?

No - SFH350V is optimized for 1000 µm plastic optical fiber (POF) with NA ≈ 0.5 and core diameter tolerance ±50 µm. Its 2.2 mm aperture and molded microlens are mismatched to standard 125 µm glass fiber geometry and numerical aperture, resulting in >20 dB coupling loss. Use only with specified POF per Infineon's mechanical interface drawings.

Is the base terminal accessible for external biasing or circuit control?

No - SFH350V is a two-terminal phototransistor (collector and emitter only); the base region is optically coupled and not brought out to a pin. It functions exclusively as a photodetector with internal base current generated by incident photons. External base connection is physically impossible due to sealed plastic housing and internal die construction.

Does SFH350V require a series current-limiting resistor on the collector side?

Yes - a load resistor (typically 1–10 kΩ) is required between collector and VCC to convert photocurrent into measurable voltage. Without it, the device operates in short-circuit mode, producing no usable output voltage swing and risking excessive power dissipation if VCE drops too low. RL value sets gain, bandwidth, and noise trade-offs per application requirements.