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Finisar FCLF-8521-3 1000BASE-T copper SFP 100m Cat5
1 Gb/s 1000BASE-T copper SFP (older gen) SFP transceiver, up to 100m Cat5.
- Manufacturer
- Coherent Corp. (formerly Finisar / II-VI)
- Mfr part number
- FCLF-8521-3
- Family
- FCLF-852x-3
- Category
- Fiber optic transceiver modules
- Datasheet
- FCLF-8521-3 datasheet (PDF)
FCLF-8521-3 specifications
| Attribute | Value |
|---|---|
| Manufacturer | Coherent Corp. (Finisar) |
| Manufacturer part number | FCLF-8521-3 |
| Product family | FCLF-852x-3 |
| Form factor | SFP (RJ-45) |
| Standards / application | IEEE 802.3 Gigabit Ethernet / 1000BASE-T |
| Data rate | 10–1000 Mb/s (up to 1.25 Gb/s) |
| Reach | 100 m Category 5 UTP (BER <10^-12) |
| Connector | RJ-45 |
| Supply voltage | 3.3 V (3.13–3.47 V) |
| Power dissipation | 1.2 W max over full voltage/temperature range (Is 320 / 375 mA) |
| Operating temperature | 0 to 85 °C case |
| Diagnostics | No optical DDM; PHY (Marvell 88E1111) accessible via 2-wire serial bus at ACh; 128-byte EEPROM |
| Compliance | RoHS compliant |
| Lifecycle | Legacy / end-of-life |
| Variant note | No link indicator (RX_LOS grounded internally); 1000BASE-X auto-negotiation enabled by default |
Optical and electrical values are from the Finisar / Coherent family datasheet; temperature grade is per part number. Confirm critical values with us before ordering.
About the Finisar FCLF-8521-3
The Finisar FCLF-8521-3 (now a Coherent Corp. product, formerly II-VI) is a SFP (RJ-45) 1000BASE-T copper SFP (older gen) copper module for 1 Gb/s links over Copper, with reach up to 100m Cat5. It belongs to Finisar's FCLF-852x-3 family, which has 2 orderable variants that differ by temperature grade, latch, receiver build or wavelength channel. This is a legacy Finisar part; we help buyers find remaining stock or a current Coherent alternative. Typical uses: Fast/Gigabit Ethernet, SONET/SDH OC-3/OC-12, campus and access links, and legacy network upgrades.
- Up to 1.25Gb/s bi-directional data links
- Hot-pluggable SFP footprint
- Extended case temperature range (0°C to +85°C)
- Fully metallic enclosure for low EMI
- 10/100/1000 BASE-T operation in host systems with SGMII interface
FCLF-8521-3: frequently asked questions
What is the Finisar FCLF-8521-3?
The FCLF-8521-3 is a Finisar SFP (RJ-45) transceiver for 1000BASE-T copper SFP (older gen) at 1 Gb/s. Finisar is now part of Coherent Corp. (formerly II-VI), and the part number is unchanged. It is used for Fast/Gigabit Ethernet, SONET/SDH OC-3/OC-12, campus and access links, and legacy network upgrades.
What is the maximum distance of the FCLF-8521-3?
The FCLF-8521-3 is specified for up to 100m Cat5 over Copper. It is a copper module, so no optical power budget applies.
Which cable does the FCLF-8521-3 use?
It is a copper module with an RJ-45 jack, so standard twisted-pair cabling plugs straight in.
Does the FCLF-8521-3 support DDM / digital diagnostics?
No optical DDM; PHY (Marvell 88E1111) accessible via 2-wire serial bus at ACh; 128-byte EEPROM.
Will the FCLF-8521-3 work in my Cisco, Juniper, Arista or HPE switch?
The FCLF-8521-3 follows the SFP MSA, so it fits any matching port. It carries Finisar's own EEPROM programming; switches that check the module vendor may need a configuration setting or a vendor-branded optic. Send us your switch model and we confirm before dispatch.
FCLF-8521-3 vs FCLF-8520-3: what is the difference?
Both are in Finisar's FCLF-852x-3 family and share the same core optics; the suffix marks a different build option (latch, receiver or ordering variant). Pick the variant that matches your temperature, latch and wavelength needs.
What does the FCLF-8521-3 part number mean?
The FCLF prefix marks Finisar's copper SFP family. The remaining characters identify the optical design and build variant.
Is the FCLF-8521-3 still available?
The FCLF-8521-3 is a legacy Finisar part, so new production is limited or ended. Next Gen Networks helps source remaining genuine stock and can suggest a current Coherent alternative with the same reach and wavelength.
What is the FCLF-8521-3 price in India and how do I order?
The Finisar FCLF-8521-3 price in India depends on quantity, delivery city and current stock. Next Gen Networks supplies it with a GST invoice (input tax credit ready) and pan-India dispatch from New Delhi. Send the part number, quantity and delivery city on WhatsApp +91-7827955775 or email Sales@nextgennetworks.in for a GST quote.
What power does the FCLF-8521-3 need?
It runs from 3.3 V (3.13–3.47 V) with power dissipation of 1.2 W max over full voltage/temperature range (Is 320 / 375 mA).
Documents
NextGen datasheetPDF · specs, FAQ & buying guideManufacturer datasheet
Finisar / Coherent family datasheet
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