Bill of Materials for Expansion Dock, or part specs?
Righty-o... does anyone know where and if a BOM (Bill of Materials) exists for the Omega2? Specifically, I want to know what parts D12, D13 and D16 are on the Expansion Dock, so I can order them if I feel I need them when making my own USB connection to the Omega2. They appear to be TVS Diodes... but what clamping voltage? 4v?
And in my travels, I find it hilarious that in this discussion on Schematics, the fact that the schematic appears to show that the VDD25 always grounded was never fully addressed. Was it just a very dodgy way of showing a single throw double pole tactile switch... meaning the reset line was grounded when the switch was released, and pulled up to VDD25 when it was pressed? I'm thinking the mounting tabs were confused for contacts when the "explaination" picture was put up... and that the switch actually has three contacts, and two anchor solder tabs!
Caio Mehlem last edited by
I'm also looking for BOMs since the schematic is missing part numbers...
@Peter-Feerick Not a complete, accurate BOM - this is a part list only.
I've cross-checked an official high resolution Omega 2+ on Expansion Dock photo and the original Omega's Expansion Dock schematic.
According to @Lazar-Demin the Expansion Dock compatible with each of Omega version - although
Pin labelling has changed but pin mapping has not. !?
I do not have any genuine Omega 'Expansion Dock' - please correct me if I'm wrong.
J4 micro USB connector (5V power input and serial terminal)
C19 10uF 10V
U13 CP2102 USB-to-UART Bridge SILICON LABS
R91 1kOhm 1% (SMD code 01B)
R92 1kOhm 1% (SMD code 01B)
R94 3kOhm (SMD code 302)
SW1 POWER SWITCH (SPDT slide switch)
U2 TD6811 Adjustable Synchronous Step-Down (Buck) Regulator Techcode (SMD code TD6811)
C18 10uF 10V
R80 1kOhm 1% (SMD code 01B)
L2 4.7uH inductor
R6 45.3kOhm 1% (SMD code 64C)
R7 10kOhm 1% (SMD code 01C)
C16 10uF 10V
U5 2x16 Omega connector
J2 female USB A connector (USB host)
R89 0Ohm (SMD code 0)
R90 0Ohm (SMD code 0)
There are no TVS diodes on the Expansion Dock.
J8 15x2 Expansion Connector / Header
D16 LED RGB 3528
R84 1kOhm 1% (SMD code 01B)
R85 1kOhm 1% (SMD code 01B)
R86 1kOhm 1% (SMD code 01B)
R95 330Ohm (SMD code 331)
SW2 RESET BUTTON (normally open momentary push button)
This is the most silly active High RESET BUTTON schematic diagram in the world
TD6811-Adj (needs 150K and 680k for Vref) SMD Code is still
@ccs-hello As you know (probably better than me R2 680k, R1 150k are recommended by the data sheet
0.6V * (1 + 680/150) = 3.32V
R2 45.3k, R1 10k are selected by Onion's HW engineer (I wonder who is he/she?)
0.6V * (1 + 45.3/10) = 3.318V - so it's OK.