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SMT electronics assembly manufacturing forum.


resistor networks- leadless vs. gull wing

danielm

#9319

resistor networks- leadless vs. gull wing | 24 September, 1999

I am in the process of picking a new resistor network for one of our new board. Since we are new to SMT i would like to get some opinions on networks. Currently we use one molded gullwing type network on our boards with no problems. Other than space is there any other advatages to going to a leadless chip type network? Price? solderability? Our pitch isn't below 25mils so shorting problems dont really effect us too much. We also have a lot of discrete resistors on the board that i would like to put in a network. Any opinions on what type of package? (Remember space is not a main consern) Thanks.

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Earl Moon

#9320

Re: resistor networks- leadless vs. gull wing | 24 September, 1999

| I am in the process of picking a new resistor network for one of our new board. Since we are new to SMT i would like to get some opinions on networks. Currently we use one molded gullwing type network on our boards with no problems. Other than space is there any other advatages to going to a leadless chip type network? Price? solderability? Our pitch isn't below 25mils so shorting problems dont really effect us too much. We also have a lot of discrete resistors on the board that i would like to put in a network. Any opinions on what type of package? (Remember space is not a main consern) Thanks. | Avoid leadless whenever possible.

Earl Moon

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jgodfrey

#9321

Re: resistor networks- leadless vs. gull wing | 26 September, 1999

| | I am in the process of picking a new resistor network for one of our new board. Since we are new to SMT i would like to get some opinions on networks. Currently we use one molded gullwing type network on our boards with no problems. Other than space is there any other advatages to going to a leadless chip type network? Price? solderability? Our pitch isn't below 25mils so shorting problems dont really effect us too much. We also have a lot of discrete resistors on the board that i would like to put in a network. Any opinions on what type of package? (Remember space is not a main consern) Thanks. | | | Avoid leadless whenever possible. | | Earl Moon | What problems have you seen with leadless ? That is all we've ever used. We switched from the convex to the convex style recently but after that we haven't had any problems.

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Earl Moon

#9322

Re: resistor networks- leadless vs. gull wing | 27 September, 1999

| | | I am in the process of picking a new resistor network for one of our new board. Since we are new to SMT i would like to get some opinions on networks. Currently we use one molded gullwing type network on our boards with no problems. Other than space is there any other advatages to going to a leadless chip type network? Price? solderability? Our pitch isn't below 25mils so shorting problems dont really effect us too much. We also have a lot of discrete resistors on the board that i would like to put in a network. Any opinions on what type of package? (Remember space is not a main consern) Thanks. | | | | | Avoid leadless whenever possible. | | | | Earl Moon | | | What problems have you seen with leadless ? That is all we've ever used. We switched from the convex to the convex style recently but after that we haven't had any problems. | | | I think it's fine you've had no problems. Maybe you never will, and I hope that to be the case.

All I'm saying is, use leaded devices whenever possible. Compliance comes to mind first as it gets down to TCE mismatch as ceramic, if that's your network's substrate material. If PCB to PCB, then that problem is not an issue bur solder joint quality now comes to mind as it is more difficult to determine visual quality attributes with leadless devices notwithstanding setting up the process.

Again, if you're using TCE matching substrates, in the 15-17 ppm/C. range, ok, if manage well your placement and inspection processes. If your network, as ceramic is 5-7 ppm and board is 15-17, there will be problems as might there be with placement and quality verification.

Earl Moon

Earl Moon

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