OP07C: OP07CP PCN

PCN# 20230327006.1
PCN# 20231031008.1

The guaranteed datasheet limits have not changed, but other characteristics might have. It is likely that your circuit relies on those characteristics; please show a schematic.

Hi Alex, 

Chen Alex1 said:

may i know if any PCN in the parts recently?

As Clemens pointed out, there are PCN issued in the product, see the PCN links. 

Chen Alex1 said:

but change back to old data code, the machine is fine,

The op amp from new FAB is the equivalent of the old die, though they may have some slight differences, such as open loop output impedance, GBWP etc. The circuit may be required to be modified if it does not meet the old design performance. 

I can help you to resolve the "issues", if you can provide me with the schematic. Generally, the op amp performance from new FAB is improved over the old FAB, but it does come with minor differences. 

If you have other questions, please let us know.

Best,

Raymond

HI sir

We production hi-pot tester ,and sales to the worldwide, you can see the below figure, IC27 is VF signal from 5kv resistor divider, close loop circuit

use the old date code, the VF is stable as below left.

use the new data code, the VF is unstable as below right.

We also use the OP07 in other circuit, likes the sample -hold circuit, still unstable, 

we already try to add 1000.450p ,100p in front of the AMp, or in back of the amp

still no any improve,

did you have any advise.thanks?

RUN rate 30k

may i know the BW diff between new & old,thanks

Hi Alex,

Thanks for the schematic. 

I have a few questions, see the image capture below. 

Chen Alex1 said:

may i know the BW diff between new & old,

I do not have the data currently. The old OP07C's GBW is 600kHz (typical). I need to find the new FAB for this. Our team just took over the product line not too long ago. 

Please let me know the question above, and I will find the root causes. 

Best,

Raymond

Hi Raymond

May I know the marking define? what is the different?

25AHS7 pass
4AA473M fail

 Hi Alex, 

Chen Alex1 said:

May I know the marking define? what is the different?

25AHS7 - referenced to old Si-die, old FAB, manufactured in May/2022

4AA473M - referenced to new Si-die, new FAB, manufactured in Oct2024. (post-PCN part)

In the early reply, I have pointed out the PCN. It is likely that the op amp is driving capacitive load, and resulting the oscillatory behavior at output in the new FAB. The op amp's output needs to be compensated, if I have the schematic. 

Best,

Raymond

hi Raymond

q1:HV node Connect  to 2 stage filter as below, then go to ADC(AD7606)

q2:we follow your test method, in series a 100 ohm & use the short probe to measure, we can see the offset is Thick, and the VF waveform also

oscillatory behavior at output

HI Raymond

I use the date code:2412 is ok, but use date code:2441 is not ok

may I know 2412 is manufacture by the old FAB? Or new FAB

According to your PCN, 2412 should  manufactured by the new FAB?

43ACCEM is ok, DC 2412, May I know  where is the fab?

Hi Alex, 

Chen Alex1 said:

43ACCEM is ok, DC 2412, May I know  where is the fab?

The information can be found below. I think that CFAB is located in Dallas, TX. The op amp is manufactured in Mexico. 

Question:

I am still trying to find out the BW and other related information on the product. This product is designed our team in Germany and that is why it takes long than usual.  

The plot below has op amp oscillatory effect at the op amp's  output, and it needs to be compensated for the new FAB. 

Could you try the parallel 470oF over 3.01kΩ resistor, and see if you are able to remove the oscillation?

0525.OP07C Oscillation issues in TW 03262025.TSC

Meantime, I am trying to get additional information about the validation data on the part. 

Best,

Raymond

hi Raymond

thanks your great support

hi Raymond

follow your rule , parallel 470oF over 3.01kΩ resistor, the result as below, level shift to negative postion

Hi Alex, 

Sorry, the suggestion did not work out.

Could you confirm where you are probing the test point in the following schematic? My understanding is that you probed at TP20, where the oscillatory effects are observed. Maybe I was misunderstood. 

Chen Alex1 said:

you can see the below figure, IC27 is VF signal from 5kv resistor divider, close loop circuit

use the old date code, the VF is stable as below left.

 On the schematic, I am trying to locate IC27, VF node and 5kΩ resistor divider, but I am unable to locate it. Please indicate the probe location and related behaviors. 

Yes, I contacted the engineers in our team in Germany. TL07C's GBW has changed from approx. 600kHz to 1.1MHz range, which is due to the new FAB change. The open loop output impedance did not change significantly. It was reported at approx. 35Ω @1MHz in the old op amp, and the new FAB op amp is measured at 42Ω @1MHz. So the oscillatory effect is due to a pole that is near the circuit's UGBW region. 

If I am able to compensate the dominated pole in the new op amp, we should be able to resolve the issue.

If you have additional questions, please let me know. 

Best,

Raymond  

Hi Raymond

On the schematic, I am trying to locate IC27, VF node and 5kΩ resistor divider, but I am unable to locate it. Please indicate the probe location and related behaviors. 

a: yes, measure the waveform from IC 27 ,TP 20.  

    not the 5kΩ resistor, in from of the IC27, The signal is come from the

    5000v output, which Attenuation by resistor divider

We use the op07 in different pcb, and module, many PCB need to be adjusted.

that is the big engineering, did you get the same issue from other Country?

Hi Alex, 

Chen Alex1 said:

that is the big engineering, did you get the same issue from other Country?

You are the first customer has issues with this OP07C part. The open loop output impedance on the new op amp did not change significantly, though the GBW is increased to approx. 1.1MHz range. So it should not have the oscillation issues that I can think of. The validation data in OP07C indicates that the new design is very similar to the old FAB, and you should not see such issues for this particular design. So I am not sure that I understand the real  problems, and I need more information from you.  

The IC27 circuit has gain of 4V/V and the circuit should have enough phase margin without oscillation in the new part. Could you answer my following questions. 

1. Did you have bypass capacitors placed next to ±15Vdc at IC27 or OP07CP op amp? I suggested to use 1uF, low ESR caps next to both ±15Vdc pins of the op amp. Without these bypass capacitors, the ripple noise will go through the op amp as observed in the scope shot. (I know that the old OP07CP is working ok as is). 

2. What are the ripple voltage amplitude in ±15Vdc? Are there high frequency components associated with the voltage rails. Your application is Hi-Pot tester and so I won't be surprised that the ±15Vdc is noisier than a typical application.  What is the switching power supply's switching frequency?

3. What are values of C23 and C24? My guess is that these values should be approx. 1nF or 100pF range. 

4. What is the intend BW for IC27 and OP07C? My guess is that it is design around 100kHz range. 

If you have other questions, please let me know. 

Best,

Raymond