I agree with John, shouldn't the external pads be larger (in my opinion, for soldering purposes)?
Jay
-----Original Message-----
John..
I'm still surprised! We have been designing 12-14 layer (standard)
smt designs for about a zillion years, maybe not quite a zillion, but
a looonnng time and no vendor has ever requested that the inner layer
pads be larger. In fact, unless I am looking at the formula/chart in
the Mil and IPC specs incorrectly, the minimum annular ring requirement
for internal is .001/.002 mils vs .002/.004 mils for external layers.
Therefore, by definition, your external pads should be larger. What
am I missing???
Regards,
Bob
begin 600 WINMAIL.DAT
M>)\^(A0/`0:0" `$```````!``$``0>0!@`(````Y 0```````#H``$(@ <`
M& ```$E032Y-:6-R;W-O9G0@36%I;"Y.;W1E`#$(`0V ! `"`````@`"``$$
MD 8`D $```$````0`````P``, (````+``\.``````(!_P\!````00``````
M``"!*Q^DOJ,0&9UN`-T!#U0"`````%1E8VA.970@36%I;"!&;W)U;2X`4TU4
M4 !496-H3F5T0$E00RY/4D<`````'@`", $````%````4TU44 `````>``,P
M`0```! ```!496-H3F5T0$E00RY/4D<``P`5# $````#`/X/!@```!X``3 !
M````%@```"=496-H3F5T($UA:6P@1F]R=6TN)P````(!"S !````%0```%--
M5% Z5$5#2$Y%5$!)4$,N3U)'``````,``#D`````"P! .@$````>`/9?`0``
M`!0```!496-H3F5T($UA:6P@1F]R=6TN``(!]U\!````00````````"!*Q^D
MOJ,0&9UN`-T!#U0"`````%1E8VA.970@36%I;"!&;W)U;2X`4TU44 !496-H
M3F5T0$E00RY/4D<``````P#]7P$````#`/]?``````(!]@\!````! ``````
M``*Q20$$@ $`( ```%)%.B!;5$5#2$Y%5%T@5FEA(&AO;&4O<&%D('-I>F4`
M^PD!!8 #``X```#-!P@`! `+`" `"@`!`!8!`2" `P`.````S0<(``0`"P`>
M``T``0`7`0$)@ $`(0```#-!040T1$8T0C4P0T0Q,3$X.4(Y,# R,$%&1#-&
M1D%%`&H'`0.0!@"4"@``(@````L``@`!````"P`C``$````#`"8```````L`
M*0```````P`N```````"`3$``0```-$```!00T1&14(P.0`!``(`3 ``````
M```XH;L0!>40&J&[" `K*E;"``!M<W!S="YD;&P``````$Y)5$'YO[@!`*H`
M-]EN````0SI<5TE.1$]74UQM86EL8F]X+G!S= `8`````````#9-ARH"E- 1
MB;D`(*_3_ZZB@ ```````!@`````````-DV'*@*4T!&)N0`@K]/_KL* ```0
M````.JU-]+4,T1&)N0`@K]/_KB [log in to unmask](%9I82!H;VQE
M+W!A9"!S:7IE``````,`-@``````0 `Y```W$Y/KH+P!'@!P``$````@````
M4D4Z(%M414-(3D5472!6:6$@:&]L92]P860@<VEZ90`"`7$``0```!8````!
MO*#KDI3T3:T\#+41T8FY`""OT_^N```>`!X,`0````4```!33510`````!X`
M'PP!````$0```&IA>61 96UA+65D82YC;VT``````P`&$**F=98#``<0%0(`
M`!X`"! !````90```$E!1U)%15=)5$A*3TA.+%-(3U5,1$Y45$A%15A415).
M04Q004130D5,05)'15(H24Y-64]024Y)3TXL1D]24T],1$5224Y'4%524$]3
M15,I/TI!62TM+2TM3U))1TE.04Q-15,``````@$)$ $```"2!@[log in to unmask]
M``!,6D9U0&!L^ ,`"@!R8W!G,3(U<C(,8&,Q`S !!PM@;I$.$# S,P\69F4/
MDD\!]P*D`V,"`&-H"L!SA&5T`M%P<G$R``"2*@JA;F\24" P`="%`= V#Z P
M-3 T%"'S`= 4$#1]!VT"@P!0`]3[$?\3"V(3X110$[(8]!30KP<3`H "D0CF
M.PEO,!K?^F4.,#4<"ATA'-\=Z1OT_QX2''\@3R -'X\=OQP/$&#\,C@EVB;Q
M)J\GN1OT)^*_)D\J'RG=*5\GCRM4.0Y0'RZD, $H(S ``H)S='GJ; >0: G@
M= ``$U #\%!D8W1L"K%<,EAAF&1J=3%P!1!G: 5".Q8R# %C"< R8 ,P<VY\
M97@7, >P!; `P )S<[$`4'-B,A10,6!A$_#T7&L)X' +D#(_,J,(8.LRD N
M93&@=CE@`4 SF[\,,#1D* `W0 2@"X!G)_'I-.9B81<09 (@-: U1N<QT#.0
M.Y$@,3$S#E VG_\WKSB_`%$Y_ "@-&X\?SV&_S$D#\ ^CS^?0*\.4#GO0P_;
M1!\]LS,"@A,08S9@2Z&3,Y ]L'1I.9 @1 $0J&%U; 5 4 K 80G X&%P:"!&
M`B$V)"5 Z&9I+0^0. % .3!0,^M'#S*C8@L@<@E04E(6H-E24G<T)4$7`' !
MT$UR?S._2I]+ID_03I %$ (P+4-/, -A.B!4;U>P4RAU8FH%D'17L$1AZ'1E
M.C8D-D__40]2'_]3+U0Y,< ][log in to unmask](/9'[!) V
M)#=9;UI_6X]<G3D/+UV_#Y!I< C08@JP=#C_2?H/5$807[]@QFH`8= +4+QY
M+T] 7+ +$6)%<S8D_R@`8S]D3V5?7*]43VM?;&_O;757TE=T6*DY;[\S/P,P
M'6FS.7.?=*]ZH$1O8_YU!X ", 703P`:`7C2>##W>'!Q40& ;E@P`& )\$V@
M[WT``@$UX%Y290#P?0`Q@))P'H!<=@B0=VL+@/YD:T" H@3P!T 080% #@#O
M<2(]@H(%`A!O!4(7(1+R#5C ;0M16, @0SI<ZEQ7`&].X6U/, ,0!Y!-A+!-
M#> #8'-O`8 @KD\!( W@?_!<AF9%`,#U`Q N2W!T?= 7$'AP-2'M9W)X`4!_
M`6XQT!KPB 0]3C1C`R 2\P" !9!L=O]!H4;0#G UX(J2`9 `((LB_X#Q?4$!
MP8J1%N /< ``1M#S#- !D" N&A**B Y0BT+_3G!XP(N_C,^-WP_ 1M %@;>/
M?Y"/D9]L:T!&T&R//_N3_Y4%*8X,)4"2WY>_E/3X8B H`I&8WXK365"6C_^;
M3YQ?G6^+`&,0GK*+CZ ?_Z$OC@PH`)Z_I#^E3Z9?BP#_> "C/ZC/J=^JY KY
M`S!X+V-Y/WK->TD@3M$)X" %`_!T3R!*;VAN+#8@,< (8&R)$ `0<77_@T 3
M@ 5 M$ 3@#5Q!)$'0&H@"K!D!"!B$X +8'(.9P20JE"P06UY(&_Z< N :0(@
MM+!_<;3 !O K!($]PG (<' 387,I/C\*A:^DL&^Q?P5 >TK\87D*A;HM9W"M
MHKL?O"\/",$T\C6@$O)B:VUK.:RS(%]]@ ,06*%A?;HMPV)/LD$+@+:!30>0
M_T90MV##8[WOOO_ #[SSQ0^7QA_'+[SS(+1C+BX*A7G,YTDGA3 Q< ,0`R!S
MQ[[log in to unmask] %N"W3?&W``GP( $``)!G.X+5/? R;O TMR%YMW*LL<M_
M$ L1*<R(<VT%0,^DGP0@N*(!H&=!L[ @>LWAO;A1(-# %O&TL # >;<!?Q-0
M!4"U8$W $X#3I[2P8M]G4,R(E5 )`(,P;M>0/>#?3= [log in to unmask]\0
M[P6Q%N $(&'B(!KPM6 'D/]8P#4@M$!8L+73"X U8 7 ]]"CS(BVO"[-< .@
M3D#*(/VTL'6GL,11S7"SL(4PUU&[log in to unmask]]X-IE?W).8&$O%M)_!4 +@,R'M>*%
MP ,@V#))_%!#M," 8$TPVL$%H1KP[<HA>;2PM>)MN#'?D(4POP!PBU"W,=F0
M/<+9HFD:\/]],LR'N*)7(;94! "-X&EP5#$OYO$RXU%L!"!V_>;3,N<RT(#G
MD[BBMB?0H]ISS'A4B3)_<6760;?P[P$!N#%-T+AB>0AAMAVTU/W<:E?:4<R'
MA2&SH.-@!!!].Y$_\%#,CO%_\EMAT&<_"Q'4@/"/]._U_\SD0F]Z8KHF>\'F
M?P'"N;HF?0(`^C ```,`$! ``````P`1$ `````#`( 0_____T `!S" !#Y-
MZZ"\`4 `"#" !#Y-ZZ"\`0L``8 (( 8``````, ```````!&``````.%````
M`````P`#@ @@!@``````P ```````$8`````$(4````````#``: "" &````
M``# ````````1@````!2A0``MPT``!X`)H (( 8``````, ```````!&````
M`%2%```!````! ```#@N, `#`"> "" &``````# ````````1@`````!A0``
M``````L`,( (( 8``````, ```````!&``````Z%`````````P`Q@ @@!@``
M````P ```````$8`````$84````````#`#. "" &``````# ````````1@``
M```8A0```````!X`0H (( 8``````, ```````!&`````#:%```!`````0``
M```````>`$. "" &``````# ````````1@`````WA0```0````$`````````
M'@!$@ @@!@``````P ```````$8`````.(4```$````!`````````!X`/0`!
9````!0```%)%.B ``````P`--/TW``!!3X4`
`
end
|
