TC1044 or LT1054?

[shawnee]

Hello guys,
   I am trying to find out if there is any advantage to using the more expensive LT0154 charge pump instead of the TC1044. The TC can handle 12v in and the LT can do 15v but other than that, is there anything else to consider? I pulled up spec sheets on both but the TC is Microchip and the LT is Texas Instruments so they don't really give the information exactly the same way. Thanks for any insight.

[madbean]

The LT1054 is capable of higher current delivery. The TC/MAX can provide about 20ma (I'd have to check the datasheet for exact values) whereas the LT can do about 4-5 times that. So, in certain applications that have high current draws the LT is a more appropriate choice. Most overdrives/distortions will never require more than the TC one if you are simply running them at 18v. But, circuits with high transistor or IC counts may require more current than it can provide. For example, a Univibe or Memory Man. In those cases, the LT is a better choice.

The other difference is that the TC needs to have pins 1 and 8 connected. This acts as a multiplier for the internal oscillator which helps take it out of the audible range. The pinout arrangement of the LT is different and pins 1 and 8 should not be connected.

[shawnee]

OK thanks Brian. I saw that the LT was good for 100ma but I didn't see what the TC could handle. The LF347 in the Boneyard looks like it only draws 8-11ma. Do you think that I'm OK with the TC1044 in the bipolar power supply circuit that I posted a few days ago that puts out +/-18v feeding the Boneyard? I ran it for an hour or so with no problems but if it is putting too much stress on the charge pump I can switch to the LT1054 for the headroom.

[madbean]

Yes, the TC1044 (SCPA) will do the job. There is no real headroom to be gain by supplying more current than needed (AFAIK) so no need to use the LT1054. Also, check into Mouser if you haven't already to see what their price is on the two different charge pumps. I don't recall them being too far off from each other.

[shawnee]

Thanks again Brian! Actually the LT1054 is around $3 and the TC1044 is about a buck.

[chromesphere]

The other difference is that the TC needs to have pins 1 and 8 connected. This acts as a multiplier for the internal oscillator which helps take it out of the audible range. The pinout arrangement of the LT is different and pins 1 and 8 should not be connected.

I must ask, does this mean the TC is a better choice over the LT as far as noise goes?  My FSH with LT has a bit of noise, my FL301 with road rage and an LT is almost unusable.  Insane amount of noise.

[aziltz]

high pitch oscillation? or white noise?

[chromesphere]

Lock me in for high pitch oscillation Aziltz!  Could be both    I think ill just have to try a TC and see if it makes a difference. Worth a shot, might have one lying around.

[shawnee]

I'm pretty sure that the oscillation frequency on the LT1054 is above the audible range already. I don't think you will get any noise reduction by swapping to the TC1044 but it's so easy to do, it's worth a shot. You may try shielded cable on the input and output of those pedals. A buffer will pull a lot of noise out as well.

[andregarcia57]

HELLO OKAY?

LT1054CP I can use?

which simply means CP? after LT1054

[andregarcia57]

I'm shopping at Farnell and I would like to know also the difference of 1044


LTC1044CN8#PBF
TC1044SCPA

http://www.farnellnewark.com.br/ci8pdip,product,55M8898,4600269.aspx


either one will work in the boneyard?
thanks

[chromesphere]

I've used one of these in the boneyard, i dont get any noise:

Edit (link fixed) - http://www.futurlec.com/TI/LT1054CN8.shtml

Paul

[andregarcia57]

I've used one of these in the boneyard, i dont get any noise:

Edit (link fixed) - http://www.futurlec.com/TI/LT1054CN8.shtml

Paul

ok, but....more will this work?
http://www.farnellnewark.com.br/ciconversordcdc8pdil,product,1196840,4480615.aspx

[TNblueshawk]

Yes that will work

[Scruffie]

The other difference is that the TC needs to have pins 1 and 8 connected. This acts as a multiplier for the internal oscillator which helps take it out of the audible range. The pinout arrangement of the LT is different and pins 1 and 8 should not be connected.

I must ask, does this mean the TC is a better choice over the LT as far as noise goes?  My FSH with LT has a bit of noise, my FL301 with road rage and an LT is almost unusable.  Insane amount of noise.

Try moving the Charge pump away from the circuit (and don't use a switching power supply) may well be heterodyning clocks.