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FPGA board form factor
1210 1 Mar 18.2020, 18:09:05
I'm working on a GW2A-18 FPGA module for integration and prototyping. Which form factor do you think it's the best if you are looking for an FPGA module? I'm aiming at development prototyping and very low volume prototype production runs. FYI, the design features are as follow: 1. 21k 4-LUTs+16k FFs 2. 42Kb distributed SRAM+828Kb block SRAM+64Mb SDRAM 3. 48 M18 DSPs (24 DSP slices, each can be configured as dual M18 or single M36, both come with MAC/ALU options) 4. 2 PLLs+4 DLLs with on board 12MHz clock 5. 34 IOs in 4 1.2V~3.3V banks+31 IOs in 3.3V banks, most IOs are true LVDS capable 6. On board SPI FLASH+FTDI downloader+FTDI UART 7. Supports Cortex M1, RiscV and ZPU 8. On board PMIC accepting single 3.5V~5.5V input with input voltage sensor 9. On chip USB HS PHY IP (under development, using DLL, PLL and IO gearbox), tentative 10. A few LEDs for heart beat and debugging, maybe one or two micro buttons As for form factor, I intentionally left out castellated hole option as I simply d...
Need help on battery protection/charger project
1709 1 Mar 17.2020, 18:17:10
Hi, I hope I'm not asking too much but I'm really stuck on this project and need help from a more experienced person. I have a single 18650 Li-Ion cell that I'm trying to protect with the AP9101 chip and also charge with the MAX1555 chip. Here's my schematic, I checked and rechecked everything and I can't seem to make it work. Right now I'm unsure about how I interconnected the two ICs, maybe it's all wrong from the start... Thanks in advance!!!
Power rail for DAC - PCB layout
1354 1 Mar 15.2020, 01:42:51
Hello, I'm trying as my hobby project to design USB DAC so far I'm okay with my PCB layout except for one thing and that is 3V3 rail for CS4398. As you can see in an attached picture it's going all around PCB. 1. Should I be worried about it? Not sure how digital power rail is important for DAC.2. If yes what would be the best solution, to break my ground plane more and route it directly, or maybe to put another LDO next to the IC?
Custom CAN-FD PCB, what to watch out for ?
1196 1 Mar 11.2020, 21:34:20
I'm designing a PCB which will communicate with a vehicle through CAN-FD at up to 2 Mbit/s. The connection to the vehicle is made though ordinary twisted-paid CAN wire (around 2m) to a Mini Universal MATE-N-LOK connector on the board. From there, it's approximately 15mm of 8 mil trace to the MCP2558FD CAN-FD tranciever, and approx. 6mm of trace to the termination resistors and decoupling capacitors. The Teensy 4.0 I use for controlling this has an integrated CAN controller, but it's only available through SMD pads on the bottom side of the PCB. Therefore, I soldered a short wire to those pads (~20-30mm) and plan on then soldering the wires to a hole in the PCB near the CAN transceiver (around 12mm of trace for the TX line, 5mm of trace for the RX line). Do I need to consider anything special here? It's my first "high-speed" signal application. Does the length / impedance of the CAN-FD traces on the board (between transceiver / connector) matter? Would the MATE-N-LOK connector be an is...
Dielectric strength of PCB perpendicular vs parallel
1325 1 Mar 11.2020, 21:24:53
Laminate suppliers only list one "Dielectric Strength" so I assumed that orientation didn't matter. Then I discovered that there are two voltage breakdown tests. Test method IPC TM-650 184.108.40.206 is used for testing perpendicular to the plane and 2.5.6 parallel to the plane. The 2.5.6 test appears to have a much lower passing threshold. So much so that IPC2221B guidelines for internal clearances come into question. Does the claimed "Dielectric Strength" value of a PCB laminate really only apply to voltages perpendicular to the plane (220.127.116.11)? Is there another name for the test results of 2.5.6? Thank you.
Designing a PCB board / graphics
1244 2 Feb 29.2020, 23:21:50
Have done before but can't figure out how I did it. Using Diptrace and overlaying a graphic but keep getting silkscreen over pad. Importing a jpeg into program after trying to cut out the background using Paint.net. not sure what it used. I Do have the gerber file from lat time but importing and editing it now??
PCB design for 40 Amps
1310 1 Feb 29.2020, 23:19:30
Hello People I want to make a dc/dc converter with specs given as follows: Vout=500V Vin=30V to 42 V Iout=2A. So, Input current will go to 40A. So, I wanted to design a PCB for the same. But I have some basic doubts.Will PCB support such high current, or is it reasonable to give such high track width. Other doubt is how to place heat sink, transformer, fan(for heat sink) and input inductor, optimally so that to avoid stray inductances. Also I have to avoid use of wires as far as possible for the same reason. Also, please help me choose the heat sink
Thermal Pad is needed or not?
835 1 Feb 28.2020, 19:33:51
How to tell whether a thermal pad is needed or not from seeing mosfet datasheet. I want to put an H bridge on a Heat Sink. so for Electrical isolation I need Thermal pads, but some of the switches don’t need because they have already insulated case and only thermal paste is fine. So how to tell?
How can I place components on both sides of my PCB in EasyEDA?
913 1 Feb 27.2020, 18:45:16
Hi guys, I have designed a Microcontrollers development board and I want to be able to keep components (the Capacitors and resistors) on both sides, the top and bottom side of the PCB to reduce the overall size of the PCB. I have designed this PCB on EasyEDA. How do I do this? Thank you.
How does impedance control on a PCB track affects the components on the PCB ?
1099 1 Feb 25.2020, 22:47:29
I'm building a PCB which needs to be impedance matched with the measuring equipment. My question is if I added impedance control to every trace, for say 50 OHM, of the PCB will it affect the resistors and capacitors already in place and change the value seen by the other components since the traces are now 50 OHM ?