KSZ8081RNDIA TR Microchip Integrated Circuit (Quad Flat No-Lead) In Stock
The KSZ8081RNDIA TR is a Microchip 10BASE-T/100BASE-TX Ethernet PHY with RMII interface support in a compact QFN package, offering auto-negotiation and HP Auto-MDI/MDI-X for flexible RJ45 connectivity. Available in stock worldwide.
- Manufacturer
- Microchip
- Package
- Quad Flat No-Lead
- Pin Count
- 25
- Lifecycle
- ACTIVE
- Datasheet
- KSZ8081RNDIA TR Datasheet PDF
- Category
- Integrated Circuit
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- RMII interface at 50 MHz simplifies connection to microcontroller Ethernet MACs with a 2-wire reduced-pin bus
- 10BASE-T and 100BASE-TX auto-negotiation with HP Auto-MDI/MDI-X for plug-and-play Ethernet connectivity without crossover cables
- Low-power QFN package with 3.3 V single-supply operation for compact IoT gateway and embedded networking designs
Applications
The KSZ8081RNDIA TR is well suited for embedded Ethernet applications in industrial controllers, IoT gateways, and single-board computers requiring a small-footprint 100 Mbps PHY interface. Its RMII interface reduces the MAC-to-PHY signal count to 9 lines compared to 18 for MII, simplifying PCB routing on tight layouts. Medical and building automation equipment also use the device for reliable wired LAN connectivity at 3.3 V with minimal external components.
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
Alternate & Equivalent Parts
Compatible alternatives and drop-in replacements for KSZ8081RNDIA TR:
Frequently Asked Questions
How does the RMII interface of KSZ8081RNDIA TR reduce PCB routing complexity compared to MII?
RMII (Reduced MII) uses a single 50 MHz reference clock and 2-bit data paths for TX and RX, requiring only 9 signal lines between the MAC and PHY versus 18 for standard MII. On a 4-layer PCB with a 100 MHz ARM Cortex-M7 MAC, this halves the length-matched traces needed for the interface, cutting routing time and reducing EMI from high-speed differential pairs.
What Ethernet speeds does KSZ8081RNDIA TR support, and how does auto-negotiation work with network switches?
The device supports 10BASE-T at 10 Mbps and 100BASE-TX at 100 Mbps, with IEEE 802.3 auto-negotiation to select the highest common speed with the connected switch or router. In a factory automation panel with a 100 Mbps managed switch, the KSZ8081RNDIA TR negotiates 100 Mbps full-duplex within 500 ms of link-up without firmware intervention.
For an IoT gateway PCB using KSZ8081RNDIA TR, what is the minimum external component count needed for a functional Ethernet port?
A typical design requires a 25 MHz crystal or 50 MHz oscillator, a 10/100 Ethernet transformer module, an RJ45 connector, and 4 to 6 bypass capacitors on the 3.3 V supply. The HP Auto-MDI/MDI-X feature eliminates the crossover detection circuit, and integrated termination reduces the external resistor count to under 10 components total per Ethernet port.
How does HP Auto-MDI/MDI-X in KSZ8081RNDIA TR simplify cable and connector selection in industrial deployments?
HP Auto-MDI/MDI-X automatically detects whether a straight-through or crossover cable is connected and reconfigures the transmit and receive pairs accordingly. This means installers can use any standard Cat5 patch cable of up to 100 m to connect an industrial controller to a switch without worrying about cable polarity, reducing field installation errors and cable inventory requirements.
What supply voltage does KSZ8081RNDIA TR require, and is it compatible with 3.3 V microcontroller I/O without a level shifter?
The KSZ8081RNDIA TR operates from a single 3.3 V supply, and its RMII data and control pins are 3.3 V CMOS compatible, enabling direct connection to STM32, NXP i.MX RT, or similar 3.3 V microcontroller Ethernet MAC interfaces without any level-shifting logic. The 3.3 V supply current is typically under 80 mA at 100 Mbps full-duplex operation.
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