Specifications
KSZ8873MLLI is Microchip’s integrated 3-port 10/100Mbps Layer 2 managed Ethernet switch IC (formerly Micrel). Suffix I denotes industrial temperature grade (-40℃ ~ +85℃), 64-LQFP tray packaging, integrating dual built-in copper PHYs + one MII host port, optimized for compact embedded industrial network equipment with low power and rich network management functionsMicrochip Technology.
👉 Distinction vs other variants
- KSZ8873MLLI: Host interface = full MII, temp -40~+85℃
- KSZ8873RLLI: Host interface = RMII (fewer IO pins)
- KSZ8873MLLJ: Extended automotive temp -40~+125℃
- KSZ8873FLLI: Two 100BASE-FX fiber PHYs instead of copper
Core Hardware Architecture
- 3-port switch fabric
- Port1 / Port2: Integrated 10BASE‑T/100BASE‑TX PHY, auto MDI/MDIX, auto speed/duplex negotiation
- Port3: MII MAC host interface for connection to MCU/FPGA/CPU
- All three ports with independent MAC layer, full wire-speed switching
- On-chip PHY advantages
- Patented analog transceiver circuit, excellent EMC anti-interference for long industrial cable
- LinkMD cable diagnostic: Detect open/short cable faults, measure cable length
- Per-port energy-saving auto power-down when link disconnected
Key Switch Layer 2 Functional Features
- VLAN & broadcast storm suppression
- IEEE802.1Q tagged VLAN, up to 16 configurable VLAN groups
- Programmable broadcast/multicast storm rate limit to avoid network congestion
- QoS traffic priority
- 4-level CoS priority queue per port, supports IPv4/IPv6 DSCP classification
- Strict priority & weighted round-robin scheduling for real-time data (video/voice)
- Full managed configuration interfaces
- Multiple host control buses: I2C, SPI, SMI (MIIM)
- Two working modes:
- Unmanaged: Configure via pin strap / external EEPROM at power-up
- Managed: Full register read/write by main processor for dynamic network adjustment
- Additional reliability mechanisms
- Port mirroring for network debugging
- Static MAC address table + dynamic learning table (48-entry)
- Port-based ingress/egress rate limiting
- Loop detection to prevent broadcast loop deadlock
Electrical Specifications
- Power rails: 3.3V digital main supply, internal 1.8V analog LDO
- Typical operating current: 88mA; ultra-low sleep mode for battery IoT devices
- Digital IO tolerant to 1.8V / 2.5V / 3.3V host logic levels
- Compliant with IEEE802.3 / 802.3u 10/100 Ethernet standards
Package & Environmental Reliability
- Package: 64-pin LQFP, 10mm×10mm surface mount
- Operating temperature: Industrial grade -40°C ~ +85°C
- Tray bulk packaging (suffix I), tape-and-reel variant KSZ8873MLLIT available
- Fully RoHS lead-free, halogen-free compliant
Typical Applications
Industrial PLC remote IO Ethernet expansion modules
CNC machine tool dual-port network data gateway
IP camera / industrial vision equipment secondary switch board
Smart factory sensor multi-node Ethernet concentrator
Vehicle industrial control dual-Ethernet redundancy communication
IP intercom, VoIP industrial voice terminal network chip
IoT gateway low-port count managed switch module
Building automation BACnet Ethernet communication equipment
Embedded Linux single-board computer multi-network expansion
Test & measurement instrument internal data exchange switch
LXB Semicon supplies original Microchip KSZ8873MLLI 3-port MII industrial managed Ethernet switch IC
