Bcm89890 May 2026

Even if you're an expert on the topic, it's always a good idea to do some research to:

The BCM89890 operates on a single 3.3V supply, but it has internal PLLs that need clean power. Use a dedicated LDO or a pi-filter from the vehicle’s main 3.3V rail.

If you’re designing a zonal architecture, you have three choices: CAN-FD (slow), 1000BASE-T1 (fast but power-hungry), or 100BASE-T1. bcm89890

The BCM89890 hits the sweet spot for 90% of in-vehicle nodes. It’s proven, it’s robust, and it’s cheap enough to put behind every sensor.

Pro tip from the bench: Make sure you follow Broadcom’s layout guide for the magnetics (or use an integrated RJ45 with magnetics for bench testing). The BCM89890 is forgiving, but proper differential pair routing on the MDI side saves you a week of EMI debugging. Even if you're an expert on the topic,

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While the BCM89890 is a 100Mbps device, it is often deployed in mixed-speed networks. Many next-generation designs pair it with a 1000BASE-T1 (1 Gbps) PHY for backbone links while keeping the BCM89890 for leaf nodes (door handles, window lifters, seat controllers). This provides a graceful upgrade path: the central switch can support both speeds, and the BCM89890 remains viable for low-bandwidth, cost-sensitive endpoints well into the 2030s. The BCM89890 hits the sweet spot for 90%

The BCM89890 is not a general-purpose chip; it is targeted precisely at specific automotive domains:

Traditional 100BASE-TX uses a PAM-5 (Pulse Amplitude Modulation 5-level) scheme over two pairs. The BCM89890 uses PAM-3 signaling over a single pair. This reduces the signal bandwidth from 125 MHz to just 33 MHz, significantly lowering radiated emissions, which is a primary concern in noise-sensitive automotive cabins.

Reliability is non-negotiable in automotive electronics. The BCM89890 is qualified to AEC-Q100 Grade 1 (or Grade 2 depending on the specific variant), meaning it is tested to withstand extreme temperature ranges and harsh electrical conditions found inside a vehicle.