VSC8201DL

Rev. 1.6.3 - 9/29/04

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Regulator Circuit

For systems with a single power supply, the VSC8201 provides an option to generate the 1.5v supply from the 3.3v supply by using the

on chip regulator. The internal regulator is enabled by having a 10k pull-up on the REG_EN pin.

To use the Regulator the following additional components are required:

•

FET device, similar to Fairchild FDT439N.

•

For decoupling, two 0.0047uF capacitors with 10% tolerance or better. NPO, X7R or X5R are all acceptable.

Systems with single 3.3v,+/-10% Wake on LAN supply

The following figure shows the circuit for generating the 1.5v supply using a 3.3v,+/-10% supply

Figure 5: Regulator Circuit using 3.3v, +/-10% supply

Key points

•

Place a 0.0047uF capacitor as close to REG_OUT as possible.

•

Place a 0.0047uF capacitor as close to the FET as possible.

•

Tie the GND line together with VREFN, capacitor connected to REF_FILT, resistor R4 (See figure above) and then connect to a com-

mon ground.

•

VREFP should be connected to the analog 3.3v plane i.e. V+A33.

media pins and convey it to the station manager.

1. Refer VSC8201 Datasheet.