DIP to SOP - Solved Fake Chinese IC

Thread Starter

Wolframore

Joined Jan 21, 2019
1,749
Another interesting thing to note is that with the DIP... if you put your finger on it... it causes capacitance changes and speeds up the oscillation... The SOP does not...

DIP is able to output and sink more current. I see what you mean... this is not their design factors... just how I'm using it... haha. So my application is not guaranteed from package to package...

I don't always play by rules... I'm trying to exploit some minor advantages to using it this way... I think there's a way around it. It’s for a non critical simple LED flasher.
 
Last edited:

SLK001

Joined Nov 29, 2011
1,548
I doubt that there is any difference, especially with your simple circuit. Either you have versions from two different families of devices (ie, ALS vs LS), or you have miss-wired your circuit. Sometimes, a DIP version and a SOIC version have different pinouts for the same device in different packages.
 

Thread Starter

Wolframore

Joined Jan 21, 2019
1,749
I’ll double check the pin outs/ divisions on the oscope. According to Datasheet it’s suppose to be the same. Only difference is that the diode gate doesn’t work.
 

Thread Starter

Wolframore

Joined Jan 21, 2019
1,749
I think my takeaway is to use the actual package when you’re breadboardig also. I’ll have to put the SOP on a board for 0.1 pins and play with a mosfet gate. It’s a better design anyhow.
 

crutschow

Joined Mar 14, 2008
25,274
I think my takeaway is to use the actual package when you’re breadboardig also.
Good idea.
But just because the breadboard works, doesn't mean the second identical circuit will, if it hasn't been designed with proper consideration for the circuit component specified limits.
 

Thread Starter

Wolframore

Joined Jan 21, 2019
1,749
E320A044-8F6A-493D-A032-CEF9888AFCF1.jpeg Update and warning. The TI chips I got from China are fake and when I ordered genuine TI chips from US source they work. I have a feeling they didn’t buffer the inputs correctly. Anyone want 200 fake chips? Top is the genuine chip
 
Last edited:

SLK001

Joined Nov 29, 2011
1,548
Send them back for a refund. :rolleyes:
Screw that... Just report them to your seller. Tell them you want a charge-back on however you paid for them. If they won't cooperate, go to your credit card provider and have THEM charge-back your costs. Ebay, Amazon and even Alibaba are good at forcing conterfeiters to pony back the money paid for their crap.

Just toss them in the trash - where they belong.
 

nsaspook

Joined Aug 27, 2009
7,495
Screw that... Just report them to your seller. Tell them you want a charge-back on however you paid for them. If they won't cooperate, go to your credit card provider and have THEM charge-back your costs. Ebay, Amazon and even Alibaba are good at forcing conterfeiters to pony back the money paid for their crap.

Just toss them in the trash - where they belong.
Obviously I was joking, just like he was about anyone wanting 200 fakes.
 

JohnInTX

Joined Jun 26, 2012
4,241
Obviously I was joking, just like he was about anyone wanting 200 fakes.
Ahh, but that’s the deal. Many bogus sellers will credit IF you agree not to give them a bad review - and they’ll lock you out if they do refund. That’s how they keep the scam going. When they DO accumulate enough bad reviews from buyers who hammer them, they just open another storefront.
 

Audioguru

Joined Dec 20, 2007
11,249
Texas Instruments datasheets and I agree than the weak low current outputs of a CD4xxx IC running on a 5V supply can typically produce 4.2mA into a dead short then two outputs in series produce only 1.8mA into a 2V red LED.

A 74HC4060 produces 42mA which is enough current to blow up the LED and blow up the IC without a current-limiting resistor.
 

Attachments

Thread Starter

Wolframore

Joined Jan 21, 2019
1,749
It's true and only if you have the real chip driving the CD chips higher you get some decent current from them.... don't forget that these chips have clamping diodes built in. the HC outputs about 25mA at 5V. It has a current clamping effect.

Update - Aliexpress refunded the money immediately no questions asked... I think the picture of real vs fake must have been enough. Gives me confidence to try again with them.
 
Last edited:

WBahn

Joined Mar 31, 2012
26,077
It's true and only if you have the real chip....

Update - Aliexpress refunded the money immediately no questions asked... I think the picture of real vs fake must have been enough. Gives me confidence to try again with them.
You might consider that a bit more deeply.

How much extra was it to buy from a reputable source? How much time did you waste on dealing with this issue? How much is your time worth (according to whatever metric makes the most sense to you)?

Was the savings really worth it?
 

djsfantasi

Joined Apr 11, 2010
6,724
You might consider that a bit more deeply.

How much extra was it to buy from a reputable source? How much time did you waste on dealing with this issue? How much is your time worth (according to whatever metric makes the most sense to you)?

Was the savings really worth it?
Yeah! Personally that reason is why Aliexpress is my LAST choice as a supplier. I’ve yet to place an order with them.
 

Thread Starter

Wolframore

Joined Jan 21, 2019
1,749
It was fine... the difference was $0.04 per chip vs $0.45 for the real ones. Enough to consider. The project has no margins so every little bit helps. I'm prob only breaking even on this project. But it's for a good cause. Had it been for more critical industry I would not have even gone the China method. It really depends on the situation.

You can pick two: FAST - CHEAP - GOOD... they needed it good and cheap...

I've had great luck with Aliexpress. I just wish they were faster - but see above rule.
 
Last edited:

dl324

Joined Mar 30, 2015
11,317
Yeah! Personally that reason is why Aliexpress is my LAST choice as a supplier. I’ve yet to place an order with them.
If you're okay with knockoffs, it can be a good deal.

I bought a PEX crimper from Home Depot for $100. A special screw came loose and got lost. I bought a replacement tool from AliExpress for under $20 and it does the job.

I used to use tools like this:

for crimping connectors like this:

But a ratcheting crimper like this:

was $12 shipped and made crimping much easier.

I was paying $0.10 each for these connectors at Jameco:

At AliExpress, they were $0.005 each in qty 500; 1/20th of the price.
 
Top