KSZ8041FTL - 10/100 Ethernet PHY with 100BASE-FX | Microchip
MPN: KSZ8041FTL ✓ ActiveKSZ8041FTL Overview
An Ethernet physical-layer transceiver, commonly called an Ethernet PHY, converts digital data from a network controller into electrical or optical-signaling-compatible signals for the physical medium. The KSZ8041 belongs to the Ethernet interface IC hierarchy, combining a 10/100 Ethernet MAC interface with mixed-signal circuitry for 10Base-T, 100Base-TX, and 100Base-FX physical channels.
The KSZ8041FTL adds 100Base-FX support to the feature set of the KSZ8041TL. This makes the FTL suitable for fiber links, media converters, and equipment that needs one Ethernet PHY to address copper and fiber interfaces. Automatic crossover handling through HP Auto MDI/MDI-X removes the need to distinguish straight-through and crossover cables in conventional copper installations.
Its mixed-signal design is intended to extend signaling distance while reducing power consumption. The device supports full MII, reduced MII, and serial MII connectivity, allowing integration with network controllers operating at different interface rates and pin requirements. The 48-pin lead-free TQFP package provides a conventional surface-mount footprint for industrial and embedded Ethernet equipment.
Typical uses include 10/100 industrial Ethernet controllers, fiber-to-copper media converters, embedded gateways, network switches, test equipment, and communication equipment requiring a single PHY with both copper and fiber support. Evaluation is supported by the Microchip KSZ8041FTL-EVAL platform, while the KSZ8041TL-FTL evaluation board covers the related TL and FTL devices.
A critical design consideration is validating the selected media mode, PHY address straps, and interface configuration at power-up. The manufacturer hardware design checklist specifically identifies reset-time strap behavior and warns that receive inputs can affect strap latching, so external hardware and software sequencing must follow the manufacturer guidance.
This page combines manufacturer-supported interface and package information with distributor availability references, practical application guidance, and engineering-focused comparison data. It also distinguishes exact verified facts from parameters that require confirmation from the current manufacturer datasheet before a new PCB or production release is approved.
Drop-in alternatives for KSZ8041FTL — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with KSZ8041FTL (same form factor and footprint) — differing in Package, Data Rate, Mixed-Signal Design, Product Type, Supply Voltage.
KSZ8041FTL-S
✅ Drop-In📋 Reference alternative (not in catalog)
KSZ8041FTL-TR
✅ Drop-In📋 Reference alternative (not in catalog)
KSZ8041TL
✅ Drop-InContact for price
View Datasheet →KSZ8041MLL
✅ Drop-InContact for price
View Datasheet →KSZ8041NL-AM
✅ Drop-InContact for price
View Datasheet →KSZ8041MNX
✅ Drop-In📋 Reference alternative (not in catalog)
KSZ8041FTL Specifications
| Ethernet Standards | 10Base-T, 100Base-TX, 100Base-FX |
| Data Rate | 10 Mb/s to 100 Mb/s |
| Supply Voltage Range | 3.135 V to 3.465 V |
| Supply Type | Single supply |
| MAC Interface | MII, RMII, SMII |
| Number of Drivers | 1 |
| Number of Receivers | 1 |
| Crossover Handling | HP Auto MDI/MDI-X |
| Package | 48-pin TQFP, 7 x 7 mm |
| Mounting Type | Surface mount |
| Terminal Finish | Lead-free |
| Shipping Package | Tray |
| Product Type | 10/100 Ethernet physical-layer transceiver |
| Copper Media Support | 10Base-T and 100Base-TX |
| Fiber Media Support | 100Base-FX |
| Mixed-Signal Design | Yes |
KSZ8041FTL tray Pin Configuration Guide
Pin configuration for KSZ8041FTL (tray package). Pin numbering, functions, and connection diagrams are defined in the manufacturer datasheet. Refer to it for the exact footprint and soldering guidelines.
No detailed pinout data available for KSZ8041FTL.
Refer to the datasheet for full pin configuration.
Typical Applications
KSZ8041FTL is suitable for 6 applications: 100Base-FX Media Converters, Industrial Ethernet Gateways, Embedded Network Controllers, Fiber Network Interface Cards, Communications Equipment, Network Test and Measurement.
100Base-FX Media Converters
The KSZ8041FTL is well matched to fiber-to-copper media converters because it combines 10Base-T and 100Base-TX copper support with 100Base-FX in one Ethernet PHY. According to the Microchip manufacturer datasheet, the FTL variant adds 100Base-FX to the KSZ8041 feature set while retaining MII, RMII, and SMII host connectivity. This allows a converter controller to manage both media paths through one device. The engineering benefit is reduced PHY count and a shared control interface, although the optical transmitter, receiver, isolation, and magnetics must still be designed for the required fiber distance and optical budget.
Recommended
Industrial Ethernet Gateways
The KSZ8041FTL suits industrial gateways that must communicate over copper networks while preserving an option for 100Base-FX connectivity. Its single 3.135 V to 3.465 V supply and mixed-signal PHY architecture simplify integration with embedded controllers using MII, RMII, or SMII. The manufacturer describes the mixed-signal design as extending signaling distance while reducing power consumption, which is useful in distributed control and factory-monitoring equipment. HP Auto MDI/MDI-X also simplifies copper installation by automatically accommodating straight-through or crossover cables. Production designs should still follow the hardware checklist for strap resistors, reset behavior, and interface timing.
Recommended
Embedded Network Controllers
KSZ8041FTL provides a standard Ethernet physical layer for embedded processors, controllers, and custom ASICs requiring 10/100 Mb/s connectivity. The verified manufacturer data confirms support for full MII, reduced MII, and serial MII, giving designers multiple host-interface options within one device. The 48-pin 7 x 7 mm TQFP is straightforward to route on a multilayer PCB, while HP Auto MDI/MDI-X reduces front-panel cabling complexity. Designers should select the appropriate interface mode in software, validate strap values during reset, and provide the manufacturer-recommended power and decoupling arrangement near the transceiver.
Recommended
Fiber Network Interface Cards
The KSZ8041FTL can serve as the Ethernet PHY in a compact network interface card that supports both copper and fiber media. Its 100Base-FX capability distinguishes it from copper-only family members, while MII, RMII, and SMII connectivity allows adaptation to different host-controller architectures. A practical implementation places the KSZ8041FTL near the network connectors and routes high-speed host signals over controlled impedance traces. The design must also isolate the optical subsystem appropriately and account for connector, fiber, and transceiver requirements. The manufacturer's evaluation platform can help verify startup, interface communication, and mixed-media behavior before a custom board is fabricated.
Recommended
Communications Equipment
The KSZ8041FTL is appropriate for communication equipment requiring a compact 10/100 Ethernet port with optional fiber reach. Supporting 10Base-T, 100Base-TX, and 100Base-FX lets one platform address legacy copper nodes and faster fiber links without changing the host-side Ethernet controller. Its single-supply 3.135 V to 3.465 V operating range and one-driver, one-receiver architecture simplify board-level planning. For telecom-adjacent or industrial systems, engineers should verify temperature grade, isolation strategy, EMC layout, and reset sequencing from the current manufacturer documentation because those limits were not quantified in the retrieved excerpts.
Recommended
Network Test and Measurement
KSZ8041FTL can be used in Ethernet test equipment, interface adapters, and protocol analyzers that need a configurable copper or fiber physical layer. The availability of MII, RMII, and SMII permits connection to instruments or controllers with different host interfaces, while the three supported media modes broaden bench coverage. Its compact 48-pin TQFP package supports dense instrument construction without relying on a large connector. Test-system designers should separate sensitive receive paths from noisy sources, follow the hardware design checklist for configuration straps, and validate link behavior with the manufacturer's evaluation board before integrating custom magnetics or optical hardware.
Recommended
Recommended Products Summary
Engineering reference data for KSZ8041FTL — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | KSZ8041FTL-S | KSZ8041FTL-TR | KSZ8041TL | KSZ8041MLL | KSZ8041NL | KSZ8041MNX |
|---|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 48-TQFP (7x7) | 48-TQFP (7x7) | 48-TQFP (7x7) | 48-TQFP (7x7) | 48-TQFP (7x7) | 48-TQFP (7x7) | 48-TQFP (7x7) |
Key Differentiators
- Adds fiber media support to the KSZ8041 copper-only family (vs KSZ8041TL)
- Supports three host-interface choices in one PHY (vs KSZ8041MLL)
- Combines copper and fiber connectivity for media converters (vs KSZ8041FTL-TR)
Design Notes
Validate PHY strap values during power-up and reset. The Microchip KSZ8041FTL Hardware Design Checklist warns that MAC receive inputs may drive high while the PHY is starting or resetting and can therefore alter the latched configuration straps. Use the manufacturer's prescribed resistor values, confirm that external circuits cannot disturb the pins, and test address and operating-mode capture across every intended power-up condition.
Place the KSZ8041FTL and its required bypass components close to the device, and keep the mixed-signal copper connection to magnetics or fiber components short. Route MII, RMII, or SMII signals as controlled-impedance traces with continuous reference planes and avoid routing them beneath noisy power-conversion stages. Because the verified excerpts do not provide exact capacitor values or layout dimensions, use the current manufacturer datasheet and hardware design checklist for final component placement and trace geometry.
Select the host interface according to timing and board-space constraints rather than treating MII, RMII, and SMII as interchangeable configurations. MII, RMII, and SMII are all supported, but their signal counts, timing, and implementation requirements differ. Confirm the selected mode, associated pin multiplexing, strap configuration, and reset behavior with the manufacturer documentation. For 100Base-FX, separately validate the optical path, isolation components, and fiber-connector implementation because the PHY's fiber capability alone does not specify the complete channel.
Compliance Information
The manufacturer datasheet states that the KSZ8041TL and KSZ8041FTL are available in 48-pin lead-free TQFP packages. Explicit RoHS, REACH, halogen-free, conflict-minerals, and automotive-qualification statements were not present in the verified excerpts.
