Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

should connector ground be connected to circuit ground?

Status
Not open for further replies.

fala

Full Member level 5
Joined
Sep 18, 2005
Messages
249
Helped
19
Reputation
38
Reaction score
4
Trophy points
1,298
Activity points
3,569
hi, I have a question about philips application note ESG89001(**broken link removed**). I think I couldn't understand one point. on page 10 it says: "it may be necessary to make a separation between
the reference-strip near to the connectors and the groundplane, groundgrid or reference of the circuitry on the PCB. This groundstrip shall, if applicable, be connected to the metal cover of the product. From this separate
groundstrip, only high impedances; inductors,resistors, reed relays and opto-couplers are allowed in between these two grounds." what it means? does it mean that connector ground should not be connected directly to circuit ground? figure 12 on page 11 just adds to my confusion these two grounds(connector and circuit) seems completely isolated for DC. I didn't understand what // in this figure means. does it mean that metal cover should not be connected to circuit ground at DC?
can someone please explain it to me ? thanks in advance.

Regards.
 

.. it may be necessary to make a separation between the reference-strip near to the connectors and the groundplane, groundgrid or reference of the circuitry on the PCB ..

This describes a very specific situation where you have connectors providing interconnections for other external panels through a PCB, which, from its point of view, has almost nothing to do with "the other blocks/panel" ..
It is obvious then that you want to keep interference between these blocks as low as possible, and an effective way of doing so is to separate their grounds/shields by total isolation (optical) or high impedance link (choke) ..

The "//" means, for example, that you can connect an inductor (RF choke) between these two grounds, and by doing so you will provide a dc reference, but in the same time, with decoupling caps at both sides, you will practically "shut down" any inteference from one side to the other and the opposite way around ..

Regards,
IanP
 

    fala

    Points: 2
    Helpful Answer Positive Rating
thanks IanP, you are really helpful. this concept has many significances for me because till now I used to connect sheild of I/O cables and also metal cover directly to my analog ground.

Regards,
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top