ICL7660SCPAZ vs TC1044SCPA

[Fontelroy]

Howdy folks, been messing around with 7660SCPAZ lately and have found them better in almost everyway to the 1044's I had been using. I don't know if there's any downsides to the 7660SCPAZ yet but they seem to play much nicer with power supplies than 1044's so if there's any trade offs folks have experienced I'd love to know!

 

[spi]

My impression is that 1044 is considered an upgrade to 7660 (spec wise anyway). I've used both without issues though. lt1054 is supposed to be better than both.

 

[Fontelroy]

I get whine with the 1044 on certain power supplies that goes away with the 7660, for me it's been quite the upgrade!
edit. I should be more specific, the 7660S is what I've been using, I believe there are versions of the 7660 that have a noticeable oscillation

 

[szukalski]

Generally, any issues I have had with whine have been resolved by swapping the 1044 for a 7660S but that's just my experience.

 

[mkstewartesq]

I generally try to use a 7660S whenever a schematic calls for a 1044 now because of prior times when using the 7660S cured charge pump whine that I was getting with a 1044.

 

[jwin615]

I think the only downside, going off memory, not datasheets, is the 7660S has less current. But iirc, was (maybe) 100ma- enough for most noise boxes.
I could be remembering completely wrong though. YOU RTFDS

 

[joelorigo]

I had a few builds that used the 1044 and when I used my TC Electronics Quintessence (digital pedal) after them, there was a whine. @music6000 turned me on to the ICL7660SPAZ and that cured that problem. I pretty much have been using them whenever a 1044 is listed. Here's the old thread:

Whine Sound In Digital Pedal After My Klone

I have a TC Electronic Quintessence that I am getting a whine sound when activated if I have it after my Aion FX Refractor (Klon). I first had both pedals in a daisy chain power supply with some others the I noticed it. Then I gave the Quintessence its own supply and the noise. Then I tired...

forum.pedalpcb.com

I'm interested to know about the lt1054 if that's better...

 

[Silver Blues]

I get whine with the 1044 on certain power supplies that goes away with the 7660, for me it's been quite the upgrade!
edit. I should be more specific, the 7660S is what I've been using, I believe there are versions of the 7660 that have a noticeable oscillation

Yep, the non-"S" versions have their onboard oscillator in the audio range and so are unsuitable for our purposes.

 

[Ginsly]

Anyone else have a strong opinion about this one way or the other? I figure PPCB docs favor 1044s over 7660s for a reason, but some people seem to prefer the latter. I have a few TC1044SCPA and a few 7660SCPAZ, just figured I'd see what people generally prefer before pluggin em in!

 

[Feral Feline]

As mentioned recently in another thread, I've often read: "Don't get the MAX1044...".

 

[jessenator]

Yes, what matters is the switching frequency—look at the data sheets. The non-S spec is guaranteed to cause unbearable auditory agony.

 

[Paul.Ruby]

Not to pile on... But never use a 7660. 1054 are perfect, just use them. But, you can use the 1044S and connect pin 1 (the boost pin) to V+ to use 45kHz oscillator. I've made the mistake of using 7660 in a muzzle and, with the raw guitar line connecting to it's key... Whine.

EDIT: I see the 7660S also has pin one as a boost pin, so that can be used, too. If there is no S, no use...

 

[Ginsly]

Not to pile on... But never use a 7660. 1054 are perfect, just use them. But, you can use the 1044S and connect pin 1 (the boost pin) to V+ to use 45kHz oscillator. I've made the mistake of using 7660 in a muzzle and, with the raw guitar line connecting to it's key... Whine.

EDIT: I see the 7660S also has pin one as a boost pin, so that can be used, too. If there is no S, no use...

So you're saying it is ok to use a 7760 after all, as long as it has the "S"?

Funny you mention 1054 - I just found a layout that specifies the LT1054. I assume that I can't just sub in one of the TC1044SCPA or 7660SCPAZ I already have? It does, however, look like the LT1054 is a drop-in replacement for the others.

I checked them out at Mouser, and there are quite a few variations. For instance, would I regret getting the less expensive LT1054IP over the LT1054CP (or any of the many other through-hole 1054 chips listed)? I appreciate the insight, this is confusing!

 

[Paul.Ruby]

The 7660S seems to be the cheapest option and must tie pin 1 to pin 8 to boost to 35kHz. Same for 1044S, which is 50% more expensive. Doesn't matter which 1054 you get. Those trailing letters of the part number are operating temperature range. The C version should be cheaper for 0-70C operation. The I version is for -40 to 85C. But the 1054 is double the price of 7660S.

 

[Ginsly]

The C version should be cheaper for 0-70C operation. The I version is for -40 to 85C.

That’s what I figured, but the lt1054cp is actually about 50% more expensive than the “ip” version at Mouser - go figure!

When it comes to the 7660s and 1044s, I have to imagine any pcb that specifically calls for those already links pins 1 & 8 like you’re saying.

It sounds like if a pcb/layout specifically called for the 1054 and you wanted to drop in a 7660 or 1044 instead, then you would likely need to put a jumper between pads 1 & 8- correct?

 

[finebyfine]

then you would likely need to put a jumper between pads 1 & 8- correct?

Yup.

There’s some newer 7660s too for what it’s worth - tc7662s can withstand a higher input voltage for example (18v for tc7662A, 15v for B suffix). I mostly use 7662s unless a pedal specifically needs the higher current output

 

[jessenator]

On Mouser the TC7660H is the same price as the S SKU: higher switching frequency, no jumper required

 

[jwin615]

I've wondered if, when using non-isolated supplies, it's more important to have CPs with multiple switching frequencies to avoid heterodyning.
Though, the higher the freq, the easier it is to filter out. But, it's still filtering to the same ground...

 

[Paul.Ruby]

That's right. I just updated my muzzle schematic and PCB to this... Two chips are shown only because I have both SMD and DIP footprints.

The SMD footprint sits within the DIP-8 and has a jumper to short pin 1 to pin 8 so I can use just about anything...

 

[Ginsly]

On Mouser the TC7660H is the same price as the S SKU: higher switching frequency, no jumper required

Gotcha. I have a handful of 7660SCPAZ and 1044SCPA, so I'm mostly trying to figure out when to use one or the other (or something completely different, like the LT1054CP). If buying new parts, the LT1054IP is about two bucks a pop at Mouser and seems like it would be a low-noise drop-in for any of these situations since it can replace the 1044 and 7660 as-is. Maybe it would be worthwhile to just stick with those..? Dunno.

I haven't encountered many instances where an LT1054 is explicitly mentioned. I came across this, but it looks like pins 1 & 8 are already bridged... Seems like in this case, I can use either of the ones I have without adding a jumper..?