MC1458: solutions require for new purchase part

Hi Janardan. 

janardan karade said:

When we place the scanning head close to the energy meter (approximately 20mm distance), the scanner output becomes unstable.

There is a PCN issued on the part, see the link below. The post-PCN MC1458 is slightly different from pre-PCN op amp. It is likely due to its wider BW and open loop output impedance characteristics. 

https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/5488/PCN20230627002.1.pdf

If you are able to provide the schematic, I will take a look at the circuit and provide suggestion to compensate the existing circuit slightly. 

janardan karade said:

When we place the scanning head close to the energy meter (approximately 20mm distance), the scanner output becomes unstable.

Does the energy meter emit radiated energy? If it does, what frequency range are we talking about? Do you have bypass capacitor next to the MC1458's power supply pin in the op amp. Please let me know. 

Best,

Raymond

.Scanner_.pdf

Dear Sir,

Regarding your query we are testing with two different smart meter and having frequency band as follows-

• RF frequency band for smart meter is- NAN Communication- RF wireless (865-867 MHz)
• GPRS frequency band for smart meter is- WAN Cellular (2G/3G/4G) (900/1800/2100/2300/2500 MHz)

Does the energy meter emit radiated energy? – Yes

When we remove the communication module (NIC card) from the energy meter, the scanner output stabilizes. We also attempted shielding enclosure, but it did not resolve the issue."

Please find attached schematic for your reference.

Please note that additionally we have mount 0.1uf/50V (PART No- CC0805KRX7R9BB104) ceramic capacitor between VCC and Ground for all four ICs (IC1, IC2, IC3 and IC5) – please refer attached schematic

Hi Janardan. 

janardan karade said:

Please note that additionally we have mount 0.1uf/50V (PART No- CC0805KRX7R9BB104) ceramic capacitor between VCC and Ground for all four ICs (IC1, IC2, IC3 and IC5)

Please make sure that the bypass capacitors are next to each op amp's supply rail  (not distance away from the +12Vdc or Vcc rail & short trace). 

It seems to me that some of the op amps are not sharing the same GND in the schematic. This may create common and differential input issues in DUT when the radiated energy is exposed. Keep all sensitive analog circuitry tied to a low impedance ground plane and use star grounding strategy (minimize ground loop).   

Which ICs are more sensitive to the UHF signal pickup in mentioned description above?  Have you tried ferrite bead + capacitive filters? Is the meter powered by battery or AC power source? Please provide me some additional details. 

Best,

Raymond

Dear Sir,

Please make sure that the bypass capacitors are next to each op amp's supply rail (not distance away from the +12Vdc or VCC rail & short trace). 

Our reply- Yes we have connected bypass capacitor (0.1uf/50V (PART No- CC0805KRX7R9BB104) directly on ICs pins between VCC and Ground for all four ICs

It seems to me that some of the op amps are not sharing the same GND in the schematic. This may create common and differential input issues in DUT when the radiated energy is exposed. Keep all sensitive analog circuitry tied to a low impedance ground plane and use star grounding strategy (minimize ground loop).   

Our reply- “We can try with a new revision of the board, but since the existing PCBs/circuit work well with the older ICs, we're trying to ensure compatibility with the new ICs without changing the PCB."

Which ICs are more sensitive to the UHF signal pickup in mentioned description above?  Have you tried ferrite bead + capacitive filters? Is the meter powered by battery or AC power source? Please provide me some additional details. 

Our reply- Ae per my observation IC1 playing major role to create the issue.

"Yes, we have tried using a ferrite bead (Part No: MMZ2012S601ATD25) in series with R5 and R6, but the issue is not 100% resolved — sometimes we still get bad results.

Another issue observed is that the scanner's sensing becomes weak when the ferrite bead is in place; it cannot detect beyond 30 mm.

We have not yet tried using a capacitive filter. Also, please note that the meter is powered  through an AC power source, generally battery is present in the smart meter for RTC and small duration to power up the meter but primary power on through ac power source only.

Hi Janardan,

Is this 1uF capacitive load after the diode? (I am not used to European notation). Anyway, if it is the 1uF capacitive load, please remove it and see if the RS immunity is improved. 

Also, I assumed that the AC power supply is able to pass the RS tests per the existing design. I will think about it and provide more suggestions, if I come up with others. 

Best,

Raymond 

Dear sir,

C44 value is 0.1uf/50V part no (CC0805KRX7R9BB104) 

after removing the c44 no change observed. problem is still exist.

Hi Janardan,

Raymond is currently out of office and will follow up on Monday July 14th. 

Best Regards, 
Chris Featherstone

Dear Chris,

Thanks for below mail update ,We are waiting for your valuable suggestions and would be very grateful for your support in the coming week

Hi Janardan,

janardan karade said:

When we remove the communication module (NIC card) from the energy meter, the scanner output stabilizes. We also attempted shielding enclosure, but it did not resolve the issue."

Could you tell me what RF NIC card model is this? When the NIC card is inserted, is the system GND's amplitude affected when the card is in operation? How does the RS immunity or the sensitivity test it? Is it tested in a anechoic chamber or a handheld scanner. 

Another question: how the Earth GND in the system or DUT is tied to during the test? 

I would like to know if the op amp's behavior is oscillation related or RS immunity related or both? Based on your description, the pre-PCN MC1458 does not have the sensitivity behavior, if I understand the issues correctly. 

In addition, please remove C6 and C4 capacitors for now. 

Best,

Raymond

Dear Sir,

We would like to share our recent observations related to RF immunity issues in our scanning head when used with smart energy meters.

On the energy meter side, we have confirmed the presence of a NIC card and noted that it uses the TI CC1190 (850–950 MHz RF front end). As you are aware, the energy meter is a sealed device, and we do not have access to its internal components. However, it is fully compliant with IS and IEC standards for EMI/EMC.

We conducted an additional test using an alternate op-amp in place of the MC1458DR. The alternate part as below:

TLV9002IDR (TI make)

Although the TLV9002IDR has an absolute maximum operating voltage of 7V, we installed and tested it under our application conditions. We observed a very stable output response, with significant improvement compared to the MC1458DR.

This suggests that the use of TLV9002IDR may help improve performance, likely due to its better bandwidth and internal architecture.

Also, please note that C4 = 0.1 µF

We hope this feedback will be helpful in identifying the cause of the earlier instability. Kindly let us know your thoughts or suggestions for further improvements.

Hi Janardan,

janardan karade said:

We observed a very stable output response, with significant improvement compared to the MC1458DR.

janardan karade said:

We hope this feedback will be helpful in identifying the cause of the earlier instability.

Thanks for the feedback. If MC1458DR has EMI issues, you have to use something else. I do not have much to add. I will inform our IC designer and take a look at the root causes. 

Here may be some other low cost options, such as TL072H, TLV9152 or others. 

If you have other questions, please let me know. 

Best,

Raymond

Dear Sir,

We understand that in previous IC lot, no issue observed as I shown in attached image of both IC but in this particular present lot having EMI issue.

• Part No- TL072HIDR
• Part No- TLV9152IDR
• Part No- OPA2192IDR

Parallelly requesting to suggest solutions for our existing IC MC1458DR which is buying from TI portal.

Apart from that one more issue reported our customers as below –

Problem Type: Influence issue affecting our scanners using iPhone

Condition: The issue appears when using an iPhone Specifically, the scanning head’s output unstable whenever the iPhone every screen turns on and off and I phone looks for face ID.

Even the iphone and scanner distance of more than one meter.

Observation: Disabling the Face ID feature on the iPhone and then working normal.

Please note that this issue occurs only with iPhones, we have not observed any issues with Android phones.

Requesting to review our shared shamanic once again and confirm if any part require to change.

Hi Janardan,

janardan karade said:

Requesting to review our shared shamanic once again and confirm if any part require to change.

Yes, please send me the schematic for a review. 

OPA2192IDR has not changed. However, PCNs are issued for TL072HIDR and TLV9152IDR and it will be good to review your schematic. 

If you prefer to share the schematic privately, please post "friendship" request via E2E and we can communicate via E2E private messaging platform or via TI's internal email. Please let me know. 

Best,

Raymond

ok sir, please share your email ID to share more details and schematics.

Hi Janardan,

Please follow the following instruction. I am unable to post my contact information in the public forum. Once we established the contact, then I can provide the contact information. 

If you prefer to share the schematic privately, please post "friendship" request via E2E and we can communicate via E2E private messaging platform or via TI's internal email. Please let me know. 

Best,

Raymond

Dear Sir,

ok we will go with TI's internal email, how we will proceed ,can you suggest??

Hi Janardan,

 Please post "friendship" request via E2E,  which is an E2E's another feature. We can communicate via E2E private messaging platform once the the message is established, and I can also provide you with the TI internal contact information then. 

Best,

Raymond

Dear Sir,

I have sent friend request please confirm to proceed .