Voltage Inverters 7660S, 7662, LT1054, TC962 Questions, findings

[Polymer]

Having had troubles with the 7660S series in the Baracuda & Surf Pi, I had a closer look
at the data sheets and whats new on the market. This list is by no means exhaustive.
Perhaps someone here has found a solution that is waaaay better. Please do post.

I couldn't find the explicit data specifying how much output current the 7660 series can supply.
This reminded me of metal detector advertising "Beware of what is not directly mentioned or hidden in footnotes" or so ...

I found the data indirectly in advertising for a newer "better" chip:



So I was wondering if the 7660S in my circuit is on its knees, because my Surf PI is already using 30mA without coil, speaker or led.

I will be testing the TC962 when I get them. I have not looked deeper into the LT1054, except that it costs quite a bit more than the TC962.

Does anyone know if the more expensive LT1054 has any advantages that justify the price in the Surf or Baracuda?

Here is pricing incl. Vat in Europe for 10pcs PDIP, Consumer version, from distributor (real chips, not re-labeled or so ...)

7660S 9.00 Euro
7662A 16.10 Euro
TC962 18.80 Euro
LT1054 47.80 Euro

What are your experiences/ideas with these Inverters?

Thank You!

[Old cart]

Having had troubles with the 7660S series in the Baracuda & Surf Pi, I had a closer look
at the data sheets and whats new on the market. This list is by no means exhaustive.
Perhaps someone here has found a solution that is waaaay better. Please do post.

I couldn't find the explicit data specifying how much output current the 7660 series can supply.
This reminded me of metal detector advertising "Beware of what is not directly mentioned or hidden in footnotes" or so ...

I found the data indirectly in advertising for a newer "better" chip:

[ATTACH]36561[/ATTACH]

So I was wondering if the 7660S in my circuit is on its knees, because my Surf PI is already using 30mA without coil, speaker or led.

I will be testing the TC962 when I get them. I have not looked deeper into the LT1054, except that it costs quite a bit more than the TC962.

Does anyone know if the more expensive LT1054 has any advantages that justify the price in the Surf or Baracuda?

Here is pricing incl. Vat in Europe for 10pcs PDIP, Consumer version, from distributor (real chips, not re-labeled or so ...)

7660S 9.00 Euro
7662A 16.10 Euro
TC962 18.80 EuroTC
LT1054 47.80 Euro

What are your experiences/ideas with these Inverters?

Thank You!

The LT1054 has been qualified for use in the New Geotech Baracuda. The TC962 looks good in terms of specs. Those prices seem high but if they are genuine they may be worth it.

[Davor]

If you need more current and higher voltage, LT1054 is a workhorse you need, but at slightly lower efficiency because it is a bipolar technology. 7660 and TC962 are CMOS, which means they are much more efficient at lower currents than LT1054. In most cases you do have low currents, and CMOS is an advantage.
I can't source TC962 locally so I did not try it yet, but specs are great.

[Polymer]

@ Old cart

I have found quite some price differences with other distributors in the meantime.
Oddly enough the lt1054 from Texas Instruments is way cheaper than the one from Linear Technology although both data sheets seem to say the same things

I used to have a business in electronic recycling, selling refurbished ic's (pulls), which were tested and sold as such.
I am quite aware of the many shenanigans going on with active & passive components, and it has become a real plague.

That's why I am so wary of fleabay or China imports for electronic components.
Troubleshooting a circuit can be demanding enough without having quirky components somewhere along the line.

This is not free advertising for distributors. They sat in their Ivory Tower long enough and seem to have changed their ways,
especially when it comes to small quantities.

Enough of that rant.

@ Davor
Thank You for your feedback. I have to order most things from abroad and manage to manage that with help of friends in different countries.

Many companies are not willing to send things to other countries and if they do, they try to charge an arm and a leg to ship, although I know it can be done with registered
mail & insurance for round 5 Euros within Europe. I'm sure you've found this too.

My question: If I were to send you chips from the EU, would customs be a problem or the disappearing of mail?

Have a nice day

[Davor]

In my case everything that comes from EU is free of customs charges, but things that come from elsewhere generally cost me twice the listed price because of all the customs, excise, taxes and other highwayman mentality charges.
Various electronic stores are even worse, because they charge a sort of flat rate fee, and if you need only a few components doing business with them is akin to robbery.
For all those reasons I tend to adjust my designs to only plain vanilla garden variety components available at a local store. There are some rewards in such Spartan attitude, especially when you learn some super sexy component fell out of vogue by ways of obsolescence.

[Old cart]

Polymer, the TC962 looks like a very good part and is cheap here in the US, just a bit over $1 each. Have not tried one yet though.

[ODM]

Also, the LT1054 and TC962 are happy with a wider voltage supply range compared to the often tortured 7660, along with generally more favorable spec, so it's a good replacement all in all.
It's always good to de-rate/overspec parts for reliable long lived use. Output resistance (eg. voltage drop under load) also rises with temperature, and those finger burning 7660s might have closer to double the output resistance.

[Polymer]

I asked at stackexchange why there is such a price difference between the TI & LT 1054's and if they are really the same funktionally.
They are the same apparently and the rest is price politics.

I'm not sure if the following applies to the way the LT1054 is used for Surf/Bara power supply, but I found this
answer at stackexchange quite interesting (concerning caps. & ESR values), it might save some headaches.

http://electronics.stackexchange.com.../143739#143739

@ODM Thank You for those insights, I am ordering new parts.

[Polymer]

Questions to the electronically adept among you, because i don't understand it and I'd hate to have it happen.

I have been going through the data sheets of the tc962 and found this concerning latch-up:



Does this apply to the way the tc962 could be used in the Baracuda or Surf PI for the power supply?
What could simply be done to mitigate this?

I didn't understand the AN763 pdf mentioned:

00763c1_cmos_latch_up.pdf