test chip does not work !

[alei]

test chip

Nothing comes out from the chip ! really do not know how to debug it.

It is a regulator design in high voltage BCD technology. I am not sure if it is the ESD problem since there is no big current for each pin.

Hope someone in this forum can help me out or give me some suggestions.

alei

 

[PaloAlto]

chip not working

You should start for the most simple parts:

* First check if you are putting it on correctly. Do you see current consumption? Is it the expected one?
* Check the references. Do you have a bandgap on the chip? Is it creating the voltages correctly?

 

[alei]

how to test chip

You should start for the most simple parts:

* First check if you are putting it on correctly. Do you see current consumption? Is it the expected one?
* Check the references. Do you have a bandgap on the chip? Is it creating the voltages correctly?

I am now testing an integrated regulator which is an IP block from company. There are five pins: VDD(4V~12V), GND, PD(low active), Vref(1.2V) and VREG(output, 3.3V).

The current consumption is not the same as expected. The current consumption is linearly increased with the VDD, and it seems independent of the PD and Vref, so weired. So, its like thee is resistor from the VDD to ground which source all the current.

there is no bandgap in this chip.

 

[PaloAlto]

ic desing working in spain

Let's assume that you have a regulator like the one shown in the attached chart.

You are forcing vref externally, vout is wrong and there is current consumption. As you can see, if the error amp is not working, there is an output transistor that could be in linear region, so you get the resistor between vdd and gnd.

Use the values of R1 and R2: Measure the voltage at vout and calculate the current through the output transistor, then knowing the dimensions, check if it is in the right OP.

Also the current through vdd minus the calculated current through output transistor equals the current consumption of the error amp. Is it correct?

There is not much you can do with only those pins, so, check the currents and try to find out if the circuit is on or not.

BTW, do you have some kind of oscillation? maybe low-freq? Try changing the value of the external cap (important also the ESR value) to see if it is a stability issue

 

[Teddy]

how to work ink chip

I know it sounds stupid but I actually saw it before therefore I am asking - Did you take ther cip under microscope and checked if there is any circuitry? If the devices are created as they were supposed to be? - especially with IP blocks it is sometimes tricky.......

 

[jt_rf]

what do test chips do

First thing that everyone should do is to check if the IC heats up as soon as the power is on for the first time.

if it heats up, first suspect the PCB.
This heating will spoil the IC and you can never check the functionality thereafter.

 

[Teddy]

what does the post test check?

WHat is PD pin??? Could you post datasheet (just piece of it) of the IP block?