BCM54240C1KFBG

BCM54240C1KFBG is a Broadcom (Avago/Broadcom) 4-port Gigabit Ethernet PHY in a Fine-Pitch Ball Grid Array package. It provides four independent 10/100/1000BASE-T physical interfaces intended to connect to a MAC on the host processor, with management via an MDIO/MDC interface. The C1KFBG suffix denotes the device revision and a 64‑/FPG-style FBGA packaging variant.
Key points:
- Four Gigabit Ethernet PHY channels (per-port 10/100/1000BASE-T)
- MDIO/MDC management interface
- Auto-negotiation, IEEE 802.3/802.3u/802.3ab compatibility
- Energy-efficient Ethernet and low-power modes
- Used in network switches, routers, NICs, and embedded networking devices
For exact pinout, electrical specs, timing, and software/register details, refer to the official BCM54240C1KFBG datasheet and product brief from Broadcom.

Pin count: 161 (FBGA package).
Function: Quad 10/100/1000BASE-T Ethernet PHYs (four PHY interfaces) with MDIO management and MAC-side interfaces (MII/RGMII/GMII) plus LED/status signals.

- Manufacturer: Broadcom Inc. (Broadcom)
- What kind of company: A global, fabless semiconductor company that designs and sells integrated circuits and related software for networking, communications, data centers, wireless, and storage.

BCM54240C1KFBG is a quad-port Gigabit Ethernet PHY (4× 10/100/1000BASE-T). Common application areas include:
- Motherboards, PCIe NICs, and other devices needing four RJ-45 Ethernet ports
- 4-port Ethernet switches (unmanaged or managed)
- Routers/gateways and edge devices with multiple LAN interfaces
- Embedded/industrial networking equipment (PLCs, HMIs, OT networks)
- Network appliances (firewalls, VPN gateways, load balancers)
Suitable for enterprise, SMB, and industrial environments requiring multi-port copper Ethernet connectivity.

FBGA – a Fine-pitch Ball Grid Array package.