SIMPLE SWITCHER®

Forum Post: RE: INT- LMZ10503 NOISE ON ENABLE PIN

YangZhang — Fri, 17 May 2013 23:44:00 GMT

I agree with you that the magnitude of the coupled noise may vary given how it is probed. The magnitude on your scope shot is higher than what I've seen. I saw peak to peak magnitude about 400mV.

The EN falling threshold is around 1V. So the noise on top of the DC EN value at 1.76V should not trigger EN falling threshold.

Regards,

Yang

Forum Post: RE: LM2676 output tolerance

Nick Nguyen — Fri, 17 May 2013 16:03:00 GMT

Thanks.

TI application engineer confirmed that the output voltage is within 2% from 0 - 3A.

Forum Post: RE: LM2673 low temperature problem

Alexander Lebedev — Thu, 16 May 2013 20:48:00 GMT

Thank you, Akshay.

You are right. My 0.47uF input cap is too far from pin 2 and this is causing instability.

Thank you for help.

Forum Post: RE: LM5575 vs. LM5005

Akshay Mehta — Wed, 15 May 2013 16:49:00 GMT

Hello Darko,

The subtle differences that are between the two parts are that the LM5575 is qualified as an automotive grade part and the LM5005 is not. Also the LM5575 belongs to the Simple Switcher family. Just as Vijay mentioned, if LM5005 fits your needs then you could go for it. If you need any help with LM5575, you could ask for it in the Simple Switcher forum.

Also, both the parts are enabled on Webench. Therefore you could get design help from the software too. The difference there being that the LM5575 is fully supported in Webench. By that I mean that it has the additional Thermal Simulation and also the Build It option that other ICs do not have. Hopefully this put more light on your question.

Regards,
Akshay

Forum Post: RE: LM26001-Q1　shutdown current

Juan Paulo Fung — Wed, 15 May 2013 02:22:00 GMT

Hello Yamauchi-san,

We have reviewed characterization data for >200 units and here are the average results:

1) -40C: ISD = 10.65uA

2) +25C:ISD = 10.6uA

3) +125C: ISD = 10.01uA

So the ISD is very consistent from temperature variation and a similar result will be expected for +95C.

Best Regards,

-JPF

Forum Post: RE: LM3150 unstable issue.

Salah Zayouna — Tue, 14 May 2013 15:23:00 GMT

This is an old post, but if you still have the problem. Here is why you have unstable issue:

C17 (100nF) is tooo big. Use only 560pF.

And BTW, D4 no need for it as there is one inside the IC. And some other design issues: like capacitors values between L3 and Q1 is too low, this will provide unclean Vin as the High frequency of the Q1 and the High impedance of the L3 at that frequency will create high ripple on the input side which is given to Vin and RON , prefer to delete the L3 or add more caps in between.

Goodluck

Forum Post: RE: Manufacturing using the LMZ12008 Switcher in a Lead Free Process

YangZhang — Mon, 13 May 2013 20:34:00 GMT

This question has been forwarded to appropriate engineers.

Forum Post: RE: LM22670 adequate for Conversion +5V - -3.3V, 2A ?

Christian Honisch — Sat, 11 May 2013 06:43:00 GMT

Hi Anston,

Thank you very much for the schematic. It is exactly what I was looking for. I'm really looking forward to try it out. However, I would be very happy if you or one of your colleagues could review my pcb layout once I have finished it. Can I replace the polymer capacitors by ceramic or low ESR tantalum capacitors? A high long term reliability is important in my application and I think that ceramic and tantalum have a higher lifetime than polymer capacitors have. Please correct me if this is wrong. Can I use the schematic also for +5V -> -5V? Is there any modification beside the gain resistor of the Opamp necessary?

Maybe one final question concerning the LM22670: Can I use 100nF (0603 or 0402) for the boot-capacitor instead of 10nF?

Best regards,

Christian

Forum Post: RE: LM2842 FB voltage not building up for LED driver application

Akshay Mehta — Wed, 08 May 2013 04:40:00 GMT

Hello Sridhar,

Would you please send some more information regarding the problem?

1) What is the input voltage range and the forward voltage on the LED? What version of LM2842 are you using (X or Y)?
2) What is the inductor part number? And what is the ripple current through the LED that the customer is designing for?
3) Is the current sense resistor rated for the right power?
4) Are there any scope plots for us to look at?
5) Would you be able to share the design layout?

Please let me know.

Thanks,
Akshay

Forum Post: RE: LMZ22010 Inverting Mode

Anston Lobo — Tue, 07 May 2013 16:40:00 GMT

Hi Guenter,

I am aware this conversion is in progress but I can't at this time guarantee any date. My hope is it will be complete by June-July timeframe.

Thanks,

Anston

Forum Post: RE: Noise on input of switching regulator, How does it affect output?

Charles Johnson — Tue, 07 May 2013 16:20:00 GMT

Akshay,

Thank you.

Regards,

Ben

Forum Post: RE: suitable dcdc converter to replace the existing LM7805 ckt.

Akshay Mehta — Tue, 07 May 2013 05:11:00 GMT

Hello Padmanabhan,

I apologize for the delay, but we'll try and get back to you soon.

Thanks for your patience.

Regards,
Akshay

Wiki: Simple Switchers Wiki

Anonymous — Sat, 04 May 2013 19:31:00 GMT

Forum Post: RE: LM5085 - Doesn't work properly

BERNARD URBANIK — Sat, 04 May 2013 01:35:00 GMT

Hi Vijay

All components are that same what WEBENCH^® Designer propose. I didn't change any parts. PFET it is install like was Design. I can change to smaller FET. I order that FET today and I will let You know when I do this. Waveforms I will send You when I change this FET.

Bests,

Bernard

Forum Post: RE: LMZ10500 FULLY ENCAPSULATED

Jimmy On-Wing Poon — Fri, 03 May 2013 18:38:00 GMT

Hello John,

The LMZ10500 doesn't offer fully encapsulated verson.

Reghards,

Jimmy

Forum Post: RE: Symmetric 5v from symmetric 30v supply

Anston Lobo — Thu, 02 May 2013 23:45:00 GMT

Yes!

Forum Post: RE: LM2663

Anston Lobo — Thu, 02 May 2013 23:17:00 GMT

Hi Felicia,

Thank you for the question. Charge pumps don't regulate their output voltage and are very dependent on capacitor placement. LM2663 has 6V Max Vin so it won't work for the 2nd stage which has 10V from pins 3 & 8.

Please see attached for solution:(Please visit the site to view this file)

Thanks,

Anston

Forum Post: RE: Two LMZ10501 Current Sharing?

Denislav Petkov — Thu, 02 May 2013 20:21:00 GMT

Hello Michael,

Unfortunately, the LMZ10501 is not designed to share current.

I am not aware of any reference design to make it work.

Regards,

Denislav

Forum Post: RE: LM22675-ADJ Feedback resistor problem

Andreas Andersson — Tue, 30 Apr 2013 06:47:00 GMT

Ahh, I understand what you're saying. And you are correct, I use the -ADJ version of the LM22675. I must have missed the part in the datasheet where it mentions the use of 5.0 version for "higher" voltage out. And I also now see that the name of generated schematics in Webench is "LM22675MR-5.0/NOPB 12.0V-24.0V to 9.0V @ 1.0A". Sometimes one need a simply remainder that things are easier than they look.

Thanks Tommy!

Forum Post: RE: dcdc converter.

padmanabhan krishnan — Tue, 30 Apr 2013 02:43:00 GMT

Goodmorning and Thanking you Dear Anston,

I have been arranging the Inductor for trials, and i will get back to you sooner. I HAVE ALSO LEARNT SOMETHING NEW WITH THIS POST.THANKYOU VERY VERY MUCH.

regards

padmanabhan.k

SIMPLE SWITCHER®

Forum Post: RE: INT- LMZ10503 NOISE ON ENABLE PIN

Forum Post: RE: LM2676 output tolerance

Forum Post: RE: LM2673 low temperature problem

Forum Post: RE: LM5575 vs. LM5005

Forum Post: RE: LM26001-Q1 shutdown current

Forum Post: RE: LM3150 unstable issue.

Forum Post: RE: Manufacturing using the LMZ12008 Switcher in a Lead Free Process

Forum Post: RE: LM22670 adequate for Conversion +5V - -3.3V, 2A ?

Forum Post: RE: LM2842 FB voltage not building up for LED driver application

Forum Post: RE: LMZ22010 Inverting Mode

Forum Post: RE: Noise on input of switching regulator, How does it affect output?

Forum Post: RE: suitable dcdc converter to replace the existing LM7805 ckt.

Wiki: Simple Switchers Wiki

Forum Post: RE: LM5085 - Doesn't work properly

Forum Post: RE: LMZ10500 FULLY ENCAPSULATED

Forum Post: RE: Symmetric 5v from symmetric 30v supply

Forum Post: RE: LM2663

Forum Post: RE: Two LMZ10501 Current Sharing?

Forum Post: RE: LM22675-ADJ Feedback resistor problem

Forum Post: RE: dcdc converter.

Forum Post: RE: LM26001-Q1　shutdown current