■ BCM5221 Product Application Note
■ BCM5220 7/7/00
Broadcom Corporation
Page 1 5221/5220-AN01 Product Application Note, Revision R
OVERVIEW
This application note contains detailed information regarding the use of the BCM5221 single channel 10/100 Physical Layer
Device. The BCM5221, capable of either 2.5V or 3.3V operation is targeted for single port or odd port copper or fiber designs
such as NIC, motherboard, additional switch port, and MAU type implementations. Dual port designs, such as a dual-port
10/100 uplinks are also discussed herein.
The BCM5221 includes the following features: Auto-MDIX switching capability, Glueless media conversion capability
(100BASE-TX to 100BASE-FX), and Cable Quality Monitoring capability.
The BCM5221 is actually a 2.5V device that includes on-chip 3.3V to 2.5V regulators making it suitable for 3.3V system ap-
plications. The BCM5221 is not suitable for applications that run exclusively at 5.0V. The system designer should consider
the BCM5201/02 for single chip 5.0V applications.
It is recommended that this application note be read in conjunction with the latest versions of the BCM5221 data sheet and
other 5221 application notes in order to ensure the most robust design possible.
The BCM5221 is available in a 64-pin 10 mm
2
PQFP package (part number BCM5221KPT).
The BCM5221 is also available in a 64-ball 8 mm
2
FBGA package (part number BCM5221KPB). This is the lowest power,
highest performing single channel PHY available today.
The BCM5220 is identical to the BCM5221 with the exception of a few features. These differences are described at the end
of this application note.
2.5V/3.3V TOLERANCE
There are three basic power supply configurations that can be used with the BCM5221. It can operate exclusively at 2.5V,
it can operate exclusively at 3.3V, or it can operate with the core running at 2.5V while the I/O runs at 3.3V. The latter con-
figuration is the most typical where low power and 3.3V digital compatibility are required.
The BCM5221 digital inputs are 3.3V tolerant and can accept 3.3V CMOS logic levels as long as the OVDD pins are tied to
3.3V. Additionally, the digital outputs will source 3.3V CMOS levels when the OVDD pins are tied to 3.3V. If the OVDD pins
are tied to 2.5V, then all digital inputs and outputs are limited to a 2.5V signal swing.
The BCM5221 is not 5V tolerant.
Figure 1 on page 2 illustrates power supply connections for the three configurations described above.
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