design files/bom

Bob Kirk

Other Parts Discussed in Thread: SE555M, SE555, CSD17571Q2

Hello.i need the design files/bom for timing circuit for our controller.The se555m should work great.6 to 12 second variable on time monostable driving n channel mosfet for relay coil with 65ma min current draw.Any help greatly appreciated.Need for gerbers.Can not use sink capabilities due to current design with external timers.smd/smt required for 2 layer pcb.

over 8 years ago

0 Arvind Sridhar over 8 years ago

TI__Mastermind 24205 points

Hi,

I have forwarded your query to the applications engineer most familiar with this part. Expect a reply soon.

Regards

Arvind Sridhar

0 Ron Michallick over 8 years ago

TI__Guru*** 145526 points

Bob,

You chose a -55C to 125C device with high temperature tolerant packages. Tell me about the environment this application will see.
How should the time be varied, potentiometer?

0 Bob Kirk over 8 years ago in reply to Ron Michallick

Prodigy 80 points

Hi Ron.We have an award winnining automotive aftermarket product from the 2015 sema convention in Las Vegas.The controller may have to to potted if installed under the hood.We really dont want to do thjis.Toyota is interested in this as a oem part for the trucks.The current timers we use are the pac tr7 programable.type which get neg. trigger pulse from door actuators.but they are externally under dash.We want to put them on the pcb of exhisting design.I think automotive temp rateing is what we have to go with.We can vary timing with pot.for calibration.We have a manufacturer working on revision of mechanical side.We need your input so we can get pcbs into production ASAP.I have a pcb designer who can run with your schematic and bom and genrerate gerber files.Very possable we will be purchasing large quanty of o you bom.as soon as prototype testing completed.

Thank You

Bob Kirk

Step-Lock inc.

602-796-9485

0 Bob Kirk over 8 years ago in reply to Arvind Sridhar

Prodigy 80 points

Thank you

0 Bob Kirk over 8 years ago in reply to Bob Kirk

Prodigy 80 points

Ron you can see our product at this link.
fetch.hightail.com/.../SEMA StepUp rev1.mp4

0 Ron Michallick over 8 years ago in reply to Bob Kirk

TI__Guru*** 145526 points

Bob,

The data sheet circuit in figure 9 should work well.
100nF is good for bypass capacitor for CONT pin. Another 100nF from VCC to ground at device is good because the SE555 timer has some through current during switching.

The formula for time is 1.1*R*C
6 seconds can be C=22uF and R = 248k
12 seconds can be C=22uF and R = 496k
There are other combinations too.

The output pull up resistor is only to get the output high close to VCC. See figure 4 to see how close output gets to VCC without the resistor.

Absolute maximum VCC is 18V, you you need to protect against load dump. if so how much voltage?

0 Bob Kirk over 8 years ago in reply to Ron Michallick

Prodigy 80 points

Hi Ron,Sorry just not available until 4:30.I looked at figure 9.Its pretty straight forward,Maybe 500k pot would work for calibration of timer.Is pull up on output necessary if driveing mosfet gate..Can you recommend a mosfet.N channel 1 amp 12.6 volt/.The load dump is not an issue as the controller is only powerd when key is off.No altenator voltage.What about gate capacitance.Logic level mosfet would be fully on with 12vdc right.Trigger is from door actuator.neg pulse.Is discrimenator needed.

0 Bob Kirk over 8 years ago in reply to Bob Kirk

Prodigy 80 points

Good morning Ron.I would like a one on one with you if possible.Can you please contact me ?

0 Ron Michallick over 8 years ago in reply to Bob Kirk

TI__Guru*** 145526 points

Bob,

Add a resistor, like 100k, in series withe the pot so that when turned to one end you won't short discharge pin to VCC.

CSD17571Q2 is a good NMOS. You can post questions about this device here; e2e.ti.com/.../
A series gate resistor can be used to control how fast the NMOS switches off and on.

The pull up resistor at output will not be needed; the VOH on SE555 is plenty high enough to tun on the NMOS.

I have meetings until 11 (2 hours)

0 Bob Kirk over 8 years ago in reply to Ron Michallick

Prodigy 80 points

Thanks Ron.what type capacitor for timing.Will tantalum polarized work or no

0 Ron Michallick over 8 years ago in reply to Bob Kirk

TI__Guru*** 145526 points

Bob,

It depends on your tolerance for change. Consider your temperature range and verify the capacitance doesn't change more then you can tolerate over temperature. The change in ESR should not matter for this application.

0 Bob Kirk over 8 years ago in reply to Ron Michallick

Prodigy 80 points

Thanks Ron.If you are available tomorrow can we talk.6027969485.I'm really pressed for time for schematic and bom.

0 Ron Michallick over 8 years ago in reply to Bob Kirk

TI__Guru*** 145526 points

Bob,

for 555 operable part numbers.

For temperature -55C to 125C
www.ti.com/.../samplebuy

For temperature -40C to 105C
www.ti.com/.../samplebuy

For temperature -40C to 85C
www.ti.com/.../samplebuy

For temperature 0C to 70C
www.ti.com/.../samplebuy

E4 means lead free
G4 is lead free and green materials

Clock & timing

Clock & timing forum

design files/bom