Comparing different packaged LT1054 Charge Pumps

[bluelagoon]

Seems there are a few different packaged types of LT1054, The 3 types I am looking at all have the same input Voltage specs 3.5V - 15V
They have the same Current Output of 100mA

Where they differ is, 2 of them aside from the Soic8 packaged LT1054C both only allow a maximum output of 26.4V
where as the Soic8 packaged one allows 30V max output.

Another thing that differs, is the packaging size, where the largest footprint SMD one is the Soic16
then there is the 8-DIP which is also larger and needs through hole mounting pads.

But the one main point of concern, to myself is the so large a price difference in disparity between the most practical sized one with the best output voltage the Soic8, cost around $10 each more than each of the other 2.

Does anyone see any limitations in using the Soic16 or the 8-Dip, where the Max output is less and the footprint is more space needy than the more expensive Soic8.?

Personally if they are all going to be close enough on par on specs, then I would rather save $10 a unit and find some extra space to manage the OS footprint of the Soic16 or Dip8 package.

Anyone else have any further considerations on this matter?




LT1054 SOIC8

LT1054 SOIC16

LT1054 DIP8

LT1054 Data Sheet

[Phend]

I just (for the first time) bought LT1054CP from Small Bear for $3.30 each + other stuff + shipping.
Used The TI diagram 8.2 page 13.
For 9 volts I figured R2 to be 170K but just used 180K.
Used a film cap for 0.002 uF
Put that 8.2 circuit on a BB and used a One Spot for power.
Works.
+9.51 in -9.10 out

Note:
Other circuits I have seen do not use all the pins, but since hard telling not knowing I used the books circuit.
(They were different Charge Pumps)

[PRR]

That's not a $14 chip. DigiKey's price is wonkey. Supply chain trouble? (All stock lost when the Dali hit the bridge??) Discontinued version, now market-price like lobster?

There's a good chance they are all the same die inside. You are not likely, in pedals, to strain the dissipation or voltage ratings. The one different rating may just be historical, like 6L6 tube ratings.

[bluelagoon]

Yeah I definitely think it is still an issue of lack of supply, with stock on hand trying to catch up with demand, but it is the same all over at present every Electronic Parts stores are charging pretty heavy for the Soic8 LT1054, even the PCB fabricators if they still have stock are charging around $12 AUD each.
Might buy the Soic16 SMD's and solder them on myself and save a few dollars.

[bluelagoon]

And dont blame the Dali, prices have been this way so far apart for years now, well before any Dali incident.
I Guess the Dali is the latest scape goat.
The Postie will be using that one next.

[ElectricDruid]

One parameter that does change between different packages is the ability to dissipate heat, so that might be a reason why one has different output specs to another. I don't think that justifies the gigantic price difference, and I wouldn't attempt to explain that.

[Rob Strand]

One parameter that does change between different packages is the ability to dissipate heat, so that might be a reason why one has different output specs to another. I don't think that justifies the gigantic price difference, and I wouldn't attempt to explain that.

That difference can be seen in the Thermal resistance spec:  16 pin 57 degC/W vs 8-pin 85 degC/W.   Voltage rating differences would be by design, by testing, or possibly as consequence of the increased thermal rating - with some effort you might be able reverse engineer if it's related to power dissipation.