DOA 40DO

DOA_40DO

40 Channel Digital Output Daughterboard.

Features:

• 40 channels
• up to 125mA per channel (continous)
• up to 50V
• open collector outputs (sinking action)
• uses DOA protocol

Note: If needed the same board layout can be used for current sourcing outputs.

 Replace the original ULN2803 by UDN2981.
 Reverse the polarity of C10.
 Do not mount or remove R9.
 Connections to CON2 have to be reversed.
 GND becomes +Vout and +Vout becomes GND

Hint: UDN2981 sometimes is known as UTC62783 or TD62783AP, depends on manufacturer and/or seller.

Schematic and Layout

Rev.0 Schematic

Rev.0 Layout

Interconnection

Typical connection for 12 volt indicators with dimming circuit and selftest (Note: no connection on Vo+)

Lamp Indicator

A note to DIYers

This board is so far one of the hardest for DIY. Lots of thin traces with spacings of often just 8mils. In addition, several wire bridges (for single-sided boards) / top side traces (for double-sided boards) are very close to IC pads. These facts make this particular board a challenge for people who are not regularly etching PCBs at home. For details, go ask on the PHCC forum.

Bill of Materials

see download page.

North American users Bill of Materials media: DOA 40DO Rev0 BOM.pdf

Eagle and Gerber files

see download page.