I've always used 0603 (1608 metric) size passives as the minimum size in my designs to optimize manufacturing. I'm told the smaller the part, the more likely it is to tombstone, stand up with only one end soldered. The common sizes below 0603 seem to be 0402 and 0201. 0402 would not seem to have a big size reduction, but if it's an advantage without penalty, why not take it. 0201 is much smaller, but I wonder about how well it would work. What sizes do you use, smaller than 0603? How much trouble do you have with them? -- Rick C. - Get 1,000 miles of free Supercharging - Tesla referral code - https://ts.la/richard11209
Easily Assembled Passive Component Sizes
Started by ●January 24, 2023
Reply by ●January 24, 20232023-01-24
On Tuesday, 24 January 2023 at 19:37:04 UTC, Ricky wrote:> I've always used 0603 (1608 metric) size passives as the minimum size in my designs to optimize manufacturing. I'm told the smaller the part, the more likely it is to tombstone, stand up with only one end soldered. > > The common sizes below 0603 seem to be 0402 and 0201. 0402 would not seem to have a big size reduction, but if it's an advantage without penalty, why not take it. 0201 is much smaller, but I wonder about how well it would work. > > What sizes do you use, smaller than 0603? How much trouble do you have with them? >0603 is a nice size if hand soldering is needed for prototypes. The smaller sizes are sometimes needed for closely packed decoupling capacitors around processors and fpgas. The smaller sizes have less inductance. If dc blocking capacitors are needed on high frequency transmission lines then 0402 or 0201 are useful because their width is closer to that of the transmission line and they therefore cause less of an impedance mismatch. The tradeoff is that smaller capacitors may need more exotic dielectrics which have worse voltage and/or temperature coefficients. For resistors, similar tradeoffs seem to happen. High precision resistors are easier to make in larger packages. High voltage components are easier to make in larger packages. Power dissipation in resistors is more complicated, generally the larger the better. Contract manufacturers often refer to anything smaller than 0603 as "dust parts". If you drop them they are gone forever! John
Reply by ●January 24, 20232023-01-24
On Tuesday, January 24, 2023 at 3:14:22 PM UTC-5, John Walliker wrote:> On Tuesday, 24 January 2023 at 19:37:04 UTC, Ricky wrote: > > I've always used 0603 (1608 metric) size passives as the minimum size in my designs to optimize manufacturing. I'm told the smaller the part, the more likely it is to tombstone, stand up with only one end soldered. > > > > The common sizes below 0603 seem to be 0402 and 0201. 0402 would not seem to have a big size reduction, but if it's an advantage without penalty, why not take it. 0201 is much smaller, but I wonder about how well it would work. > > > > What sizes do you use, smaller than 0603? How much trouble do you have with them? > > > 0603 is a nice size if hand soldering is needed for prototypes. The smaller sizes are sometimes > needed for closely packed decoupling capacitors around processors and fpgas. The smaller sizes > have less inductance. If dc blocking capacitors are needed on high frequency transmission lines > then 0402 or 0201 are useful because their width is closer to that of the transmission line and they > therefore cause less of an impedance mismatch. > The tradeoff is that smaller capacitors may need more exotic dielectrics which have worse voltage > and/or temperature coefficients. > For resistors, similar tradeoffs seem to happen. High precision resistors are easier to make > in larger packages. High voltage components are easier to make in larger packages. Power dissipation > in resistors is more complicated, generally the larger the better. > Contract manufacturers often refer to anything smaller than 0603 as "dust parts". If you drop them > they are gone forever!They also treat $100, 20 pin TSSOPs as "dust" parts. Seems the machine sometimes doesn't like a part orientation and tries to drop it in a bin, but the part goes flying instead! Not worried about any high frequency issues. I will have a BGA on the board and the 0603/1608 will take up all the space of two balls on the back side. So an 0402/1005 with the pads would be about two ball areas. An 0201/0603 would just be one ball area and even more mountable around the vias. Any parts that can't be had in X5R, I'd bump up the size. It's not like I don't have any 0805 or 1206 parts on the board. I'm looking at replacing some op amps that can't be bought with a class D speaker driver chip. Seems to quell the high frequency noise, they indicate significant inductors. They go up in value with higher impedance loads for some reason. They have 33 uH with an 8 ohm load, so I'm worried I'd need hundreds of uH for a 50 ohm load. One on each of four outputs would be a bit much. So I'm looking at shrinking everything else I can. -- Rick C. + Get 1,000 miles of free Supercharging + Tesla referral code - https://ts.la/richard11209
Reply by ●January 24, 20232023-01-24
> > They also treat $100, 20 pin TSSOPs as "dust" parts. Seems the machine sometimes doesn't like a part orientation and tries to drop it in a bin, but the part goes flying instead! > > Not worried about any high frequency issues. I will have a BGA on the board and the 0603/1608 will take up all the space of two balls on the back side. So an 0402/1005 with the pads would be about two ball areas. An 0201/0603 would just be one ball area and even more mountable around the vias. > > Any parts that can't be had in X5R, I'd bump up the size. It's not like I don't have any 0805 or 1206 parts on the board. > > I'm looking at replacing some op amps that can't be bought with a class D speaker driver chip. Seems to quell the high frequency noise, they indicate significant inductors. They go up in value with higher impedance loads for some reason. They have 33 uH with an 8 ohm load, so I'm worried I'd need hundreds of uH for a 50 ohm load. One on each of four outputs would be a bit much. So I'm looking at shrinking everything else I can. >Find a contract house that can handle 201 without tombstoning... -- This email has been checked for viruses by Avast antivirus software. www.avast.com
Reply by ●January 24, 20232023-01-24
On Tuesday, January 24, 2023 at 5:18:17 PM UTC-5, TTman wrote:> > > > They also treat $100, 20 pin TSSOPs as "dust" parts. Seems the machine sometimes doesn't like a part orientation and tries to drop it in a bin, but the part goes flying instead! > > > > Not worried about any high frequency issues. I will have a BGA on the board and the 0603/1608 will take up all the space of two balls on the back side. So an 0402/1005 with the pads would be about two ball areas. An 0201/0603 would just be one ball area and even more mountable around the vias. > > > > Any parts that can't be had in X5R, I'd bump up the size. It's not like I don't have any 0805 or 1206 parts on the board. > > > > I'm looking at replacing some op amps that can't be bought with a class D speaker driver chip. Seems to quell the high frequency noise, they indicate significant inductors. They go up in value with higher impedance loads for some reason. They have 33 uH with an 8 ohm load, so I'm worried I'd need hundreds of uH for a 50 ohm load. One on each of four outputs would be a bit much. So I'm looking at shrinking everything else I can. > > > Find a contract house that can handle 201 without tombstoning...That sounds like the often seen step in instructions, to do something "carefully". They never say just how "carefully". I never know if I should use the NIST traceable "careful" or if the generic, low-ball Chinese "careful" is sufficient. Not to mention when they don't bother to distinguish the Imperial "careful" or the metric "carefûl". It might only be 1 part in 10 different, but how do I know if that's important or not? -- Rick C. -- Get 1,000 miles of free Supercharging -- Tesla referral code - https://ts.la/richard11209
Reply by ●January 24, 20232023-01-24
On Tue, 24 Jan 2023 22:18:09 +0000, TTman <kraken.sankey@gmail.com> wrote:> >> >> They also treat $100, 20 pin TSSOPs as "dust" parts. Seems the machine sometimes doesn't like a part orientation and tries to drop it in a bin, but the part goes flying instead! >> >> Not worried about any high frequency issues. I will have a BGA on the board and the 0603/1608 will take up all the space of two balls on the back side. So an 0402/1005 with the pads would be about two ball areas. An 0201/0603 would just be one ball area and even more mountable around the vias. >> >> Any parts that can't be had in X5R, I'd bump up the size. It's not like I don't have any 0805 or 1206 parts on the board. >> >> I'm looking at replacing some op amps that can't be bought with a class D speaker driver chip. Seems to quell the high frequency noise, they indicate significant inductors. They go up in value with higher impedance loads for some reason. They have 33 uH with an 8 ohm load, so I'm worried I'd need hundreds of uH for a 50 ohm load. One on each of four outputs would be a bit much. So I'm looking at shrinking everything else I can. >> >Find a contract house that can handle 201 without tombstoning...If you use visible reference designators, there's not a lot of advantage of going below 0603. For super low impedance, use the sideways caps. Current necks down into a 0402 or 0201 cap. Actually, few applications actually need a tiny cap.
Reply by ●January 25, 20232023-01-25
On Tuesday, 24 January 2023 at 21:06:01 UTC, Ricky wrote:> I'm looking at replacing some op amps that can't be bought with a class D speaker driver chip. Seems to quell the high frequency noise, they indicate significant inductors. They go up in value with higher impedance loads for some reason. They have 33 uH with an 8 ohm load, so I'm worried I'd need hundreds of uH for a 50 ohm load. One on each of four outputs would be a bit much. So I'm looking at shrinking everything else I can.A balanced filter with a pair of 33uH inductors driving an 8 ohm resistive load will have a low-pass corner frequency of about 19kHz. A higher load resistance will need more inductance to get the same corner frequency. John
Reply by ●January 25, 20232023-01-25
On Wednesday, January 25, 2023 at 3:10:23 AM UTC-5, John Walliker wrote:> On Tuesday, 24 January 2023 at 21:06:01 UTC, Ricky wrote: > > > I'm looking at replacing some op amps that can't be bought with a class D speaker driver chip. Seems to quell the high frequency noise, they indicate significant inductors. They go up in value with higher impedance loads for some reason. They have 33 uH with an 8 ohm load, so I'm worried I'd need hundreds of uH for a 50 ohm load. One on each of four outputs would be a bit much. So I'm looking at shrinking everything else I can. > A balanced filter with a pair of 33uH inductors driving an 8 ohm resistive load > will have a low-pass corner frequency of about 19kHz. A higher load resistance > will need more inductance to get the same corner frequency. > JohnA higher resistance will have a higher corner frequency, no? The switching noise is what needs to be eliminated. That's around 400 kHz, or 20 times higher. I guess the idea is to have significant suppression at 400 kHz, with minimal impact on the 20 kHz pass band. Funny, that this corner frequency being pushed close to 20 kHz would seem to be the design point, yet the different makes of these chips specify different values of inductors, although not wildly different. I guess some are trying not to crowd the pass band. So it's not likely I'll be able to use a class D amp then. The class AB amps seem to be limited to 5V power as they are mostly intended for earphones. The LM8272 was a perfect part for the job, with few alternates. I guess that's why it's still such a long lead time while other parts seem to be easing up and more available. I used the LM8262 for two sockets that aren't driving the outputs, but I still need these parts for the output drivers. Space is tight on the board, and the stereo differential drivers would have freed up some space. I still don't get how the semiconductor market was in fine shape before 2020 and now, three years later, still has not settled. It's not like anyone retired production capacity. Is anyone planning to build more capacity off the bleeding edge? -- Rick C. -+ Get 1,000 miles of free Supercharging -+ Tesla referral code - https://ts.la/richard11209
Reply by ●January 25, 20232023-01-25
On a sunny day (Wed, 25 Jan 2023 00:10:18 -0800 (PST)) it happened John Walliker <jrwalliker@gmail.com> wrote in <53941776-1d15-4d47-981f-b0c12691678dn@googlegroups.com>:>On Tuesday, 24 January 2023 at 21:06:01 UTC, Ricky wrote: > >> I'm looking at replacing some op amps that can't be bought with a class D >speaker driver chip. Seems to quell the high frequency noise, they indicate >significant inductors. They go up in value with higher impedance loads for >some reason. They have 33 uH with an 8 ohm load, so I'm worried I'd need hundreds >of uH for a 50 ohm load. One on each of four outputs would be a bit >much. So I'm looking at shrinking everything else I can. > >A balanced filter with a pair of 33uH inductors driving an 8 ohm resistive load >will >have a low-pass corner frequency of about 19kHz. A higher load resistance >will >need more inductance to get the same corner frequency. >JohnI do not like the switching audio amps, killed an ebay one once, rest frequency feedthrough after filter? I build a real analog one around the TDA7924 >20 years ago, is still working great (on about 12/7) and those are still available on ebay: https://www.ebay.com/itm/162149310109 Best audio power chip I have ever seen: http://panteltje.com/panteltje/amplifier/index.html
Reply by ●January 25, 20232023-01-25
On Wednesday, January 25, 2023 at 5:09:27 AM UTC-5, Jan Panteltje wrote:> On a sunny day (Wed, 25 Jan 2023 00:10:18 -0800 (PST)) it happened John > Walliker <jrwal...@gmail.com> wrote in > <53941776-1d15-4d47...@googlegroups.com>: > >On Tuesday, 24 January 2023 at 21:06:01 UTC, Ricky wrote: > > > >> I'm looking at replacing some op amps that can't be bought with a class D > >speaker driver chip. Seems to quell the high frequency noise, they indicate > >significant inductors. They go up in value with higher impedance loads for > >some reason. They have 33 uH with an 8 ohm load, so I'm worried I'd need hundreds > >of uH for a 50 ohm load. One on each of four outputs would be a bit > >much. So I'm looking at shrinking everything else I can. > > > >A balanced filter with a pair of 33uH inductors driving an 8 ohm resistive load > >will > >have a low-pass corner frequency of about 19kHz. A higher load resistance > >will > >need more inductance to get the same corner frequency. > >John > I do not like the switching audio amps, killed an ebay one once, > rest frequency feedthrough after filter? > > I build a real analog one around the TDA7924 >20 years ago, > is still working great (on about 12/7) > and those are still available on ebay: > https://www.ebay.com/itm/162149310109 > > Best audio power chip I have ever seen: > http://panteltje.com/panteltje/amplifier/index.htmlNot trying to drive 8 ohms, not trying to drive many watts. Just trying to drive 50 ohms, single ended and 600 ohms differential. The entire board is not much larger than the devices you are talking about, 115 mm x 23 mm x ~ 10 mm. The main point of using the audio amp chip, is they replace three dual op amp chips, 3 x 5 mm each. But as it turns out, the original design was pretty optimal for the requirements. I used positive feedback with a small output resistor (12.1 ohms) to generate a 50 ohm output. Works the champ. I just can't get the LM8272MM due to the chip shortage and it's not getting any easier yet. Know any other MSOP8 dual op amps that can source/sink 100 mA? I can't find any. This one drives capacitive loads well too. -- Rick C. +- Get 1,000 miles of free Supercharging +- Tesla referral code - https://ts.la/richard11209