Practical layout design: power/gnd supply, transmission signal path width?

[rfle]

Hello everyone.

In some large power consumption circuits, especially Power Amplifier (PA) the current supply is quite high: 10mA ~ 100 mA. In the layout, how wide are the supply wires (vdd, gnd) to provide that current? If the supply wires are too narrow while the running current is too high, it may cause the wires burning, doesn't it? Further more, the PA should provide 10~20 dBm output signal, which also create a large number of AC current flowing in a signal path, then how large should a signal line be to transmit this current ??

The inductor also play as vdd supply for a PA and for example in 0.18 CMOS process the maximum width is 4 um. Is this wide enough to provide 10~100 mA current. To the best of my knowledge, the rule of thumb is 1 um for 1 mA. So how come people can build PA with 30 dBm output power in such process??
Could anyone provide some information? Thank you

 

[ismbn]

I asked a lot of people for the same problem...
the almost same answer I got.

they are saying that if the fabricator make the 35 micrometer depth in side the board and if the thickness of the track is 1mm~(39.37 mil) 1A current can pass though it with any problem...



Mohammed Ismail

 

[rfle]

I asked a lot of people for the same problem...
the almost same answer I got.

they are saying that if the fabricator make the 35 micrometer depth in side the board and if the thickness of the track is 1mm~(39.37 mil) 1A current can pass though it with any problem...



Mohammed Ismail

Hi Ismail, what do you mean by "35 micrometer depth inside the board", are you talking about PCB design? My question is for micro analog IC design, the line width is so much thinner, few micro metter only . Anyway good to know your information you provide. Thanks

- - - Updated - - -

I asked a lot of people for the same problem...
the almost same answer I got.

they are saying that if the fabricator make the 35 micrometer depth in side the board and if the thickness of the track is 1mm~(39.37 mil) 1A current can pass though it with any problem...



Mohammed Ismail

Hi Ismail, what do you mean by "35 micrometer depth inside the board", are you talking about PCB design? My question is for micro analog IC design, the line width is so much thinner, few micro metter only . Anyway good to know your information you provide. Thanks

 

[Mityan]

Why you so care about internal IC design? I think that if manufacturer declares some operational and absolute maximum ratings you should trust them.
What about power of 20 dBm... Thats only 100 mW, every cell phone can transmit even more. And take a look at cell phone design, it's rather midget.

By the way, as the second poster said, if 1 A current is not a problem for 35 um thick and 1 mm wide wire, so your 4 um is enough to pass 100 mA with the same 1 mm width. By the way, if you have 100 mW power, 100 mA current corresponds to 1 V voltage supply. For greater voltage your current will be less I think.

 

[ismbn]

@rfle... sorry i was in wrong train................

 

[rfle]

Why you so care about internal IC design? I think that if manufacturer declares some operational and absolute maximum ratings you should trust them.
What about power of 20 dBm... Thats only 100 mW, every cell phone can transmit even more. And take a look at cell phone design, it's rather midget.



By the way, as the second poster said, if 1 A current is not a problem for 35 um thick and 1 mm wide wire, so your 4 um is enough to pass 100 mA with the same 1 mm width. By the way, if you have 100 mW power, 100 mA current corresponds to 1 V voltage supply. For greater voltage your current will be less I think.

Why cant I not care about internal IC design? and if you just accept whatever people tell you then why you are here.

The output power is the output power to the load, normally 50 Ohm, not related to supply voltage.

 

[Mityan]

Ah, sorry. Power delivered to the load is current times voltage but it is different from power supply voltage.