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.

some examples for practical LATCH UP?????

Status
Not open for further replies.

mahendra

Junior Member level 1
Joined
Feb 25, 2005
Messages
16
Helped
2
Reputation
4
Reaction score
2
Trophy points
1,283
Activity points
1,473
Hi all

I want to find practical situations of latch up when an IC powered with clean power supply.Plz help in this regard.Thnx in advance.
 

One example of latchup is if one leaves Nwell floating.
Another example is if one has a small number of substrate or Nwell contacts, a fast switching large transistor can change local substrate of Nwell potential by capacitive coupling. That can trigger latchup in proper curcumstances.
Both scenerious can happen with perfectly clean supplies.
 
HI
Thanx for the reply.

if low frequency circuit then how it reacts for the latch-up???

Let us discuss with one example,Low frequency OP-AMP.ALL SUBSTRATE CONTACTS ARE CONNECTED TO THE POWER RAILS. What r causes of latch-up in this case??
 

If circuit is slow, all supplies are ideal and Nwell and Pwell are connected to supply and gnd rails, then no latchup is possible.

BUT, is power-up and power-down of your circuit slow enough?
Can nearby digital circuit inject minority carriers into the common substrate that diffuse to your slow op-amp and fire latchup then?
Is input of your op-amp is clean of high-frequency components? Can output be overdriven?
All these reasons can lead to the latchup, albeit much less probable for a slow circuit.
 

    mahendra

    Points: 2
    Helpful Answer Positive Rating
Thts good.


Thanx a lot.I could get some conclusions.

Regards
Mahendra
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top