Maxim HFRD-34.0 manual Schematics, Component List, and Layout Drawings, Gerber Files and Firmware

8Schematics, Component List, and Layout Drawings

The full schematics, component list, and PCB layout drawings are available to download in PDF format at:

http://www.maxim- ic.com/tools/other/appnotes/4232/4232_softwar e.zip.

See sections 10 and 11 for additional details regarding the use of the schematics and layout drawings for new designs.

9 Gerber Files and Firmware

The Gerber files and firmware assist design engineers in developing their projects, and are available to Maxim customers upon request. See sections 10 and 11 for additional details regarding the use of Gerber files and firmware. To receive the Gerber or firmware files, please send an email to StrategicApps@maxim-ic.com with HFRD-

34.0in the subject line. Include the following information:

1.Your name

2.Company name

3.Company website

4.Brief description of your project

10 Design Notes

Please review the following design notes:

1.Line Out1 and Line Out2 are designed to drive an audio line impedance (> 1kΩ) with typical line-out voltage levels. These two audio outputs can be optimized to drive headphone loads by changing external component values. See the MAX9728 data sheet for additional information.

2.The USB hub controllers (U26, U27, U36, and U39) have configurations and settings that can be adjusted through a 2- wire bus controlled by the ￿C. Currently

Reference Design HFRD-34.0 (Rev.3, 05/08)

these features and configurations are set through the ￿C firmware.

3.The USB HUB reset connection for the four HUBs (pin 26 of USB2512 and USB2513 devices) are tied together on the current version of the reference design. Splitting these connections to have individual control will improve the overall USB switching operation.

4.If desired, U47 (MAX3420) is provided to facilitate control of the switch through a USB interface. Currently these features are not preprogrammed into the reference design.

5.USB HUB 4 is a self-powered HUB (power is drawn from the HFRD-34.0 supply). USB HUBs 1-3 are powered from the host. All USB HUBs include overcurrent shutdown protection.

6.It is recommended that you increase the supply filtering (i.e., add series inductance and bulk capacitance) of the host USB power supplies (for HUBs 1-3) in order to reduce crosstalk from the USB power- supply noise to the audio outputs.

7.The power MOSFET transistors (Q2- Q13) used for switching the USB host power are flipped over due to a layout error in the pin order. When copying this section of the design, the transistor footprint should be corrected.

8.The ATMEL ￿C (U49, ATMEGA168) can be in-circuit reprogrammed to perform custom features. Use the AVRISP-MKII programmer and the connections provided through J15.

9.A 10kΩ pull-up resistor should be added to pin 9 of the MAX3420 (U47) in any design revisions.

10.Connecting pins 14 and 16 together on each DVI input will increase the

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