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.

Register Log in

Protection diodes dual diodes vs single TVS

Status
Not open for further replies.
M

mscaff

Junior Member level 3
Joined
Jun 19, 2001
Messages
25
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Location
Brasil
Activity points
138
protection diodes across the regular

Hi,

I'm trying to protect my microcontroller inputs and outputs using a series resistor
and a protection diode.
I just don't know if is better to use dual diode (like BAV99) connected across vcc, my signal and gnd,
or use a single TVS (like MMBZ6V8AL ) connected across my signal and ground.

Thanks, Mauricio
 

Hi mscaff,

if you connect a dual diode across vcc, input and gnd the following could happen:
If the interference at the input is of high energy, your vcc could rise too high.
To interface the µc to 24V (for example) I use a voltage divider made of two resistors
(output voltage ca. 5 Volt) and connect a zener diode 4.7 Volt parallel to the lower
resistor. If the upper resistor and the zener are big enough, this circuit can "eat" a lot of power (burps).

thomaz
 

The TVS is much better but may end up being more expensive than the voltage divider and zener. Take a look at AVX, they have some very nice varistors in SMD packages costing about us$0.20 each.
 

hehehe good point thomaz!!! :smile:

best,
//a
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top