Cluso's CpuBlade - a footprint question before production
Cluso99
Posts: 18,069
I have a requirement for a small footprint cpu module. I will be making it available, as a raw pcb, pcb & parts, and an assembled pcb.
My pcb has a QFP prop with socketed xtal, overclocking design (typically 104+MHz) with smt caps underneath, 64KB Eeprom TSSOP8, and a SOT23 3V3 regulator under the prop which can take 6Vin max (from a typical 5V supply). It has a pinout that permits 5V & Gnd to be fed into 2 pins and a sequence of Gnd,-Reset, P31, P30 for connecting a propplug. Therefore an external reset switch can be added to the Gnd & -Reset pins. No reset switch is on the pcb. A 10K pullup will be on the reset pin. As is my normal practice, SDA & SCL will both have 10K pullups. Currently the design is layed using a 4x10K smt network. The underside caps are 0805.
I require a small footprint that is 1"x1".
However, I could add the standard "inner" pinout of the Prop ProtoBoard outside my footprint and make the pcb 1.2"x1.2".
For those who may be interested in this pcb, what is your preference? (1"x1" or 1.2"x1.2"?)
The pcb will be silk screened (labelled) both sides with white on blue solder resist.
BTW I solder my pcbs by hand using just a flux pen, fine solder, and a fine tipped temperature controlled soldering iron (and the occasional solderwick).
My pcb has a QFP prop with socketed xtal, overclocking design (typically 104+MHz) with smt caps underneath, 64KB Eeprom TSSOP8, and a SOT23 3V3 regulator under the prop which can take 6Vin max (from a typical 5V supply). It has a pinout that permits 5V & Gnd to be fed into 2 pins and a sequence of Gnd,-Reset, P31, P30 for connecting a propplug. Therefore an external reset switch can be added to the Gnd & -Reset pins. No reset switch is on the pcb. A 10K pullup will be on the reset pin. As is my normal practice, SDA & SCL will both have 10K pullups. Currently the design is layed using a 4x10K smt network. The underside caps are 0805.
I require a small footprint that is 1"x1".
However, I could add the standard "inner" pinout of the Prop ProtoBoard outside my footprint and make the pcb 1.2"x1.2".
For those who may be interested in this pcb, what is your preference? (1"x1" or 1.2"x1.2"?)
The pcb will be silk screened (labelled) both sides with white on blue solder resist.
BTW I solder my pcbs by hand using just a flux pen, fine solder, and a fine tipped temperature controlled soldering iron (and the occasional solderwick).
487 x 479 - 85K
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John Abshier