FE50MSNR 650 nm DC-50 MBd 50 m SMI POF Non-Inverting Transceiver

Yes. Its signal path is specified from DC to 50 MBd, so it can convey static optical levels, low-frequency PWM and NRZ digital data without requiring a minimum transition rate. At the upper limit, the minimum unit interval is 20 ns and the stated maximum frequency is 25 MHz. The FE50MSNR can therefore provide an optical physical layer for systems based on RS232, RS485, Modbus or PROFIBUS, provided the external interface circuitry and protocol timing remain within the electrical and timing limits. For long idle periods or burst traffic, the initial receiver pulse-width distortion should be checked alongside the steady-state timing figures.

The FE50MSNR uses a non-inverting transmitter and non-inverting receiver, so a logic-high electrical input produces light and detected light produces a logic-high receiver output. The FE50MSIR has the same non-inverting transmitter but uses an inverting receiver, reversing the receive-output polarity. This distinction matters when replacing copper links, handling serial-interface idle states or connecting directly to programmable logic with a defined active level. During receiver power-up, the output remains in a high-impedance state and settles within 40 µs after VCC reaches the operating threshold. Variant selection should therefore consider both normal logic polarity and the equipment’s required start-up and fail-state behaviour.

Either rail can be used, with electrical performance validated at 3.3 V and 5 V supplies within ±5%. A 3.3 V rail is preferred where the connected logic permits it because the typical transmitter current is 16.5 mA at 3.3 V compared with 17.5 mA at 5 V. The transmitter and receiver may use separate rails, although operating both from the same supply is recommended. During start-up, VIN must not exceed VCC because the transmitter driver could otherwise enter an uncontrolled logic state. The +7 V value is an absolute maximum rating and must not be treated as an operating supply limit; normal operation above 5.5 V is not specified.

The 50 m figure should be treated as an installation-dependent link distance rather than an unconditional cable-length guarantee. Peak transmitter output is specified from −9 dBm to −1 dBm, while the receiver optical-high range extends from −22 dBm to −1 dBm. Comparing the minimum launch level with the minimum high-level threshold gives a simple 13 dB loss allowance before accounting for engineering margin. Fibre attenuation, connector losses, bending, contamination, temperature and ageing must all fit within the final optical budget. Optical figures are stated as peak values, so measurements taken as average power on 50% duty-cycle data will be approximately 3 dB lower and must be interpreted accordingly.

Allow for up to 30 ns of transmitter propagation delay and up to 50 ns of receiver propagation delay for either transition, giving as much as 80 ns of internal end-to-end delay before adding the installed link’s additional delay. At 50 MBd, one unit interval is 20 ns, so fixed latency may span several unit intervals even though it does not directly reduce the steady-state eye opening. Transmitter pulse-width distortion is limited to −3 ns to +3 ns, while receiver PWD is specified at up to ±4 ns or ±6 ns depending on received optical power. The first three received pulses can show −7 ns to +14 ns distortion. Burst protocols should therefore include enough preamble or timing tolerance for the initial pulses to settle.

Pins 1 and 12 are EMI shield connections and should be tied to the PCB signal-ground plane to reduce Tx-to-Rx crosstalk and improve shielding against external interference and ESD. The layout also requires particular attention around pins 6 and 7, where 1.2 mm by 1.5 mm oval solder-pad areas are specified on the top and bottom copper. The component is suitable for wave soldering but not for reflow soldering, and hand soldering is not recommended for production. The soldering limit is 260 °C for ten seconds, once only, at least 2.2 mm from the lead root. The dust plug may remain fitted during processing but must remain below 110 °C, and Moisture Sensitivity Level 2a handling controls apply.

The FE50MSNR is specified for −40 °C to +85 °C operation and carries IEC 60825-1 LED Class 1, RoHS and JEDEC Human Body Model Level 2 ratings. The HBM level of 2 kV to less than 4 kV is a component-handling rating and does not represent finished-equipment immunity to external ESD events. Likewise, the mention of medical control, patient safety and voltage isolation describes possible application areas rather than complete medical-equipment or functional-safety certification. Designers must still establish the required creepage, clearance, insulation, EMC and equipment-level safety performance. The optical link can support galvanic separation, but no system isolation-voltage rating is defined for the completed installation.