KSZ8721BT - 10/100 Ethernet PHY Transceiver | Microchip
MPN： KSZ8721BT ✗ 停產KSZ8721BT 概覽
An Ethernet PHY transceiver is an interface IC that converts parallel digital Ethernet data into physical signaling for copper or optical media, while receiving and decoding incoming signals. The KSZ8721 belongs to the PHY hierarchy: Ethernet interface IC, physical-layer transceiver, 10/100 Ethernet PHY, and network interface semiconductor. Supporting both copper and fiber media makes it useful in industrial control, embedded networking, communications equipment, and factory automation systems.
Verified source information identifies the KSZ8721 as a 10BaseT/100BaseTX/FX physical-layer transceiver with MII and RMII host connectivity. The RMII option can reduce host pin requirements compared with a parallel MII arrangement, which is valuable when conserving connector and processor I/O resources. The 100BASE-FX capability supports fiber links where electrical copper reach or electromagnetic environments make optical media preferable. Exact PHY tolerances, clock requirements, link-distance targets, and electrical thresholds must be confirmed in the manufacturer datasheet before design release.
The 48-TQFP surface-mount package is suitable for automated PCB assembly and compact multilayer boards. Its exact pin functions, exposed-pad arrangement, supply connections, and grounding requirements were not supplied in the verified excerpts, so they must not be inferred. Designers should preserve the manufacturer's recommended magnetics, termination network, RJ45 layout, fiber-isolation boundary, and high-speed trace topology. Decoupling and return paths are particularly important because Ethernet PHY performance depends on clean references and controlled common-mode behavior.
Typical uses include 10/100 Ethernet links in embedded controllers, industrial Ethernet gateways, serial-to-Ethernet equipment, network switches, test instruments, and optical-to-copper media converters. The combination of MII, RMII, copper, and fiber support lets one device bridge several common legacy network-interface architectures. Exact suitability for a particular MAC, processor, transformer, optical module, or cable length must be verified against the complete datasheet and system timing requirements.
This page consolidates the verified manufacturer, distributor, and datasheet-index information while clearly separating missing technical data. Its engineering value is the application guidance, sourcing context, and explicit compatibility boundaries rather than guessed specifications. Before purchasing or laying out a replacement board, verify lifecycle status, exact electrical limits, pinout, media support, and package details against the authoritative Microchip documentation.
This page also distinguishes verified facts from open engineering questions. Because the excerpts do not supply a complete electrical table, package drawing, lifecycle statement, or pin-level map, each missing item is marked rather than estimated. That conservative approach is essential for Ethernet hardware, where an incorrect pin assignment, unsupported interface mode, or inappropriate power assumption can prevent link negotiation or damage a design.
直接替換替代品，適用於 KSZ8721BT — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： KSZ8721BT （相同外形與佔位） — 差異在於 Package, Product Type, Supply Voltage.
KSZ8721CL
✅ 直接替換聯絡詢價
查看資料表 →KSZ8721SL
✅ 直接替換聯絡詢價
查看資料表 →KSZ8721BI
✅ 直接替換聯絡詢價
查看資料表 →KSZ8721BL
✅ 直接替換聯絡詢價
查看資料表 →KSZ8721
✅ 直接替換📋 參考替代品（不在目錄中）
KSZ8721BT 規格
| Ethernet Data Rate | 10 Mbps or 100 Mbps |
| Copper Ethernet Support | 10BaseT and 100BaseTX |
| Fiber Ethernet Support | 100BaseFX |
| Host Interface | MII and RMII |
| Transceiver Channel Count | 1 channel |
| Supply Description | 3.3 V single power supply |
| Low-Voltage Operating Point | 2.5 V operation described by source excerpt |
| 封裝 | 48-pin TQFP |
| Package Dimensions | 7 mm x 7 mm |
| 安裝類型 | Surface mount |
| Physical-Layer Functions | 10BaseT PMA, PMD, and PCS functions |
| Product Category | Ethernet interface IC |
| Manufacturer | Microchip Technology |
| Original Brand Reference | Micrel Semiconductor |
| RoHS 狀態 | unknown |
| REACH Status | unknown |
| AEC-Q100 Qualification | not_applicable |
KSZ8721BT 7 mm x 7 mm 腳位配置指南
KSZ8721BT（7 mm x 7 mm 封裝）的腳位配置。 腳位編號、功能與連接圖定義於製造商資料手冊中。請參閱該手冊以取得確切的封裝尺寸與焊接指引。
無詳細腳位定義資料： KSZ8721BT.
請參閱 資料表 以查看完整腳位配置。
典型應用
KSZ8721BT 適用於 6 應用s: Embedded Ethernet Controller Interface, Industrial Ethernet Gateway, Copper-to-Fiber Media Converter, Network Switch Port PHY, Test and Measurement Ethernet Port, Communications Equipment with Legacy MII.
Embedded Ethernet Controller Interface
The KSZ8721BT fits embedded systems requiring a 10/100 Ethernet physical layer without implementing PHY signaling directly. Its verified MII and RMII interfaces let the designer match the host controller's available bus and timing architecture, while 10BaseT and 100BaseTX support covers common link negotiation rates. The 48-TQFP package is suitable for automated surface-mount assembly, although the exact pin map and timing limits must come from the complete datasheet. Validate controller voltage levels, clocking, reset behavior, and media magnetics before schematic release.
推薦
Industrial Ethernet Gateway
KSZ8721BT is a candidate for industrial gateways that need copper connectivity plus optional fiber reach. The verified 100BaseFX capability can support media designs where copper distance, grounding, or electromagnetic conditions favor optical communication, while 10BaseT and 100BaseTX serve local equipment links. Both MII and RMII give designers flexibility when connecting an embedded processor or communications controller. Industrial suitability remains conditional because the supplied excerpts do not establish temperature range, surge immunity, or certification.
推薦
Copper-to-Fiber Media Converter
The combination of 10BaseT, 100BaseTX, and 100BaseFX makes the KSZ8721BT relevant to copper-to-fiber conversion equipment. A host controller can manage link and media coordination through MII or RMII while the PHY faces both electrical copper and optical media through its documented external networks. Designers must verify required optical transceiver topology, isolation, receive sensitivity, transmit wavelength, and supported fiber distance in the full datasheet. Layout must preserve separation between the copper and fiber domains.
推薦
Network Switch Port PHY
KSZ8721BT can serve as a physical-layer element in 10/100 network-interface designs when the surrounding controller or switch fabric supplies the required host-side signaling. Its verified one-channel transceiver architecture and 10/100-rate support align with one port per PHY, while MII or RMII connectivity accommodates different switch-controller arrangements. Designers should verify clock distribution, digital I/O levels, reset sequencing, and per-port magnetics. The excerpts do not provide throughput, latency, or fanout specifications.
推薦
Test and Measurement Ethernet Port
The KSZ8721BT is potentially appropriate for test and measurement instruments requiring 10/100 Ethernet communication. Copper and fiber support can simplify instrument interoperability across laboratory networks, and RMII may help preserve host-controller I/O when board space is constrained. Interface timing, isolation strategy, EMC requirements, and cable reach must be reviewed against the target installation environment. The verified material does not identify safety isolation, EMC, or environmental ratings, so those requirements must be handled at the system level.
推薦
Communications Equipment with Legacy MII
KSZ8721BT supports systems whose host controller still exposes an MII interface and needs a dedicated Ethernet PHY. The MII path preserves compatibility with controllers designed around a parallel PHY bus, while copper and 100BaseFX media expand connection choices. A replacement design should compare pin-level signal direction, bus width, clock requirements, supply sequencing, and media-side network components against the incumbent device. The verified excerpts establish interface compatibility at the family level but do not provide a full timing table.
推薦
推薦產品摘要
工程參考資料，適用於 KSZ8721BT — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | KSZ8721CL | KSZ8721SL | KSZ8721BI | KSZ8721BL | KSZ8721 |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Drop-In Verification | Reference device | Family comparison only; manufacturer pin and parameter confirmation required | Family comparison only; manufacturer pin and parameter confirmation required | Family comparison only; manufacturer pin and parameter confirmation required | Family reference only; manufacturer pin and parameter confirmation required | Family base MPN; exact suffix compatibility requires confirmation |
主要差異化特點
- Verified combination of copper and fiber media support (對比KSZ8721BI)
- Dual host-interface positioning (對比KSZ8721CL)
- Verified 48-pin TQFP target format (對比KSZ8721BI)
- Transparent sourcing at the recorded date (對比KSZ8721SL)
設計說明
Treat copper and fiber networks as separate high-speed analog domains. Follow the manufacturer's recommended magnetics, terminations, isolation, and component-placement diagrams exactly. Keep the Ethernet differential path away from switching nodes and preserve a continuous return path. The verified excerpts do not provide trace dimensions, so impedance targets must be taken from the complete datasheet and board stack-up rather than guessed.
Resolve the apparent supply-description mismatch before schematic capture: the indexed datasheet describes 3.3 V single-supply operation, while another Micrel excerpt describes 2.5 V operation. Check the exact KSZ8721BT datasheet for core, analog, and I/O supply pins, allowed voltage rails, sequencing, and decoupling values. Do not assume that every PHY supply pin accepts the same voltage.
Choose MII or RMII according to the host controller's clocking and I/O budget, then validate setup and hold timing across the complete interconnect. RMII can reduce parallel host signals, but it still requires controlled clock and data relationships. Because the supplied excerpts do not contain timing tables or pin assignments, use the official KSZ8721 documentation for edge rates, clock modes, and interface-specific layout.
Do not approve a KSZ8721BT replacement based only on the KSZ8721 family name or TQFP-48 label. Verify every pin name and direction, package drawing, supply voltage, clock requirement, media support, reset behavior, and magnetics interface. A same-package suffix can still change ordering code, temperature grade, lead finish, or supported functions, so manufacturer confirmation is required.
合規資訊
The supplied verified excerpts do not directly establish RoHS, REACH, lead-free, halogen-free, or conflict-minerals status for KSZ8721BT. The product is an Ethernet interface IC rather than an automotive-qualified device in the verified data.
