PCB Assemblies without Enclosures

[dipmicro]

You came here because you are curious what is this product.

We received batch of 100pcs PICkit2 Clones. Due to miscommunication they had no enclosures. Plus after retesting them, I found out these units do not work as expected due to improperly substituted components.

Here is the original Microchip schematic.

Here is the clone schematic.

Problems with the original units:

1. VDD cannot be regulated lower than 4.5-4.7V, which means if the 3.3V part is programmed in programmer-powered circuit, the part would be possibly damaged.

I found out this issue exists due to rail-rail opamp in Microchip's original being substituted by non-rail-rail type in the clone. We have switched the LM358 for MCP6002 (dual version of MCP6001 used in original).

2. The original uses 680uH/33ohm L1, while clone uses 470uH/4ohm. While inductance is not the issue, I found out that the low DC resistance of L1 causes the V_TGT to drop significantly when VPP_PUMP is activated. I have tried to source the proper inductor, tried several types, but was not too succesfull. Instead we have fixed it by reducing the stimuli to the Q6 by installing an extra resistor between base and emiteur.

I have also tried adding serial resistance to L1 or installing additional stabilising resistor into emiteur. While some of these solutions may be better, they might require cutting traces and is much more difficult to do that than add ezxtra part. Solution with bleeder between Q6 base and emiter seems to be stable enough.

The units are fully tested and we are selling them with reduced price. They come with all accessories, just do not have the plastic enclosure and have been repaired. If you don't mind, this is your chance to get an excellent inexpensive tool.

We have worked with manufacturer and they will be updating the design so the next batch we receive will be fully functional and should be tested by our test procedure.