SMSC8720A Microchip Integrated Circuit (Quad Flat No-Lead) In Stock
The SMSC8720A is a compact single-chip 10/100 Mbps Fast Ethernet PHY transceiver from Microchip Technology, supporting RMII host interface and HP Auto-MDIX for automatic cable crossover detection in embedded networking designs. It operates from a 3.3V supply in a small QFN package with low power consumption, ideal for cost-sensitive microcontroller-connected Ethernet applications. Available from authorized distributors with in-stock inventory and worldwide shipping.
- Manufacturer
- Microchip
- Package
- Quad Flat No-Lead
- Pin Count
- 25
- Lifecycle
- ACTIVE
- Datasheet
- SMSC8720A Datasheet PDF
- Category
- Integrated Circuit
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- RMII interface with 50MHz reference clock requires only 9 signals to the MAC, simplifying PCB routing compared to MII 18-signal alternatives
- HP Auto-MDIX eliminates the need for crossover cables, allowing direct connection to any Ethernet port without hardware reconfiguration
- 10/100 Mbps dual-speed operation with auto-negotiation ensures backward compatibility with existing 10BASE-T network infrastructure
- Low-power 3.3V single-supply design with power-down mode reduces standby consumption in battery-backed embedded networking nodes
- Small QFN footprint enables Ethernet connectivity on compact 2-layer PCBs in space-constrained IoT and industrial devices
Applications
The SMSC8720A provides plug-and-play 10/100 Ethernet connectivity for microcontroller-based embedded systems including industrial PLCs, building automation controllers, and smart meter communication modules. Its RMII interface integrates directly with popular MCU families such as STM32, LPC, and SAM series processors, reducing the MAC-to-PHY routing complexity. It is also widely used in low-cost network-attached sensor nodes, home automation hubs, and embedded HMI panels where a minimal-BOM Ethernet solution operating from a single 3.3V rail is required.
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
Alternate & Equivalent Parts
Compatible alternatives and drop-in replacements for SMSC8720A:
suggested
suggested
Frequently Asked Questions
How does the SMSC8720A Auto-MDIX feature benefit embedded Ethernet deployments in industrial cabinets?
HP Auto-MDIX in the SMSC8720A automatically detects and corrects straight-through vs. crossover cable wiring without any firmware intervention or jumper changes. In industrial cabinet installations where patch cables are replaced frequently by field technicians, this eliminates the risk of connecting two straight-through cables between two devices and losing the link. The feature operates at both 10Mbps and 100Mbps, covering all Fast Ethernet speeds supported by the PHY.
What is the RMII interface signal count, and why does it simplify MCU-to-PHY PCB routing versus MII?
The RMII interface uses only 9 signals between the MAC and the SMSC8720A PHY, compared to 18 signals for the full MII interface. On a 2-layer or 4-layer PCB, the reduced signal count cuts the number of controlled-impedance traces nearly in half, lowering board cost and simplifying layout in compact embedded designs. The 50MHz reference clock shared between MAC and PHY also eliminates one independent clock source.
At what supply voltage does the SMSC8720A operate, and does it require a separate 1.8V digital core rail?
The SMSC8720A operates from a single 3.3V supply for both its analog and digital sections, with an internal regulator providing the lower core voltage. This single-supply design simplifies power architecture compared to PHYs that require an external 1.8V rail, reducing the number of LDOs or DC-DC converters on the board and making it straightforward to power directly from a standard 3.3V system bus.
For a battery-powered IoT gateway, how does the SMSC8720A manage power when the Ethernet link is idle?
The SMSC8720A supports a hardware power-down mode that reduces total device current consumption to well below 1mA when the Ethernet link is not needed. In Wake-on-LAN-capable designs, the PHY can be held in power-down by the host MCU and activated only when a network event is detected, extending battery life by hours in deployments where Ethernet is used intermittently rather than continuously for data bursts of 100Mbps.
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