LMZM33606: Module not working

senthil kumar

Prodigy 30 points

Part Number: LMZM33606

Hi Team,

we are using LMZM33606RLXR in our board

Project: Test Equipment

Module 1: 30V to 5V (Default 4.5V, in parallel resistance concept we will achieve 5V and 5.5V)

Module 2: 30V to 12V (Default 11.5V, in parallel resistance concept we will achieve 12V and 12.5V)

For more details refer the schematic.

Module 1 is working and we are getting expected voltage range.

Module 2 is not working and we are not getting any clue why this module is not working.

we compared the each pin impedance w.r.t GND. Both looks same not difference.

Can you help us to troubleshoot the module.

Few Observation

Module 2: output voltage measured 1.7V to 2.01V and FB voltage in mV

Module 1: Output voltage measured 4.5V and FB voltage 1.007V

over 2 years ago

+1 Arief Hernadi over 2 years ago

TI__Mastermind 23815 points

Hi,

Could you check the following?
1) the values of resistors that are connected to FB pin are the correct value
2) Check the VCC voltage pin. It should read somewhere in the range of 3.27V

3) Remove the capacitors on the SS pin and see if it is startup.

Alternatively here is a webench design for an example

https://webench.ti.com/appinfo/webench/scripts/SDP.cgi?ID=4C948BB8364D4374

Thanks

-Arief

+1 senthil kumar over 2 years ago

Prodigy 30 points

Hi Arief,

Thanks, sure I'll check your suggestion.
Additional info: we have manufactured 7 boards for testing purposes.
Out of 7 boards, only one board has this module problem. rest all 6 boards working fine.

on FB resistor as per datasheet it is recommended to connect 10K at RFBB. I got the mail TI customer support team on the same (Refer the attachment)

We replaced the chip, Still the problem is present. :(

Regards,
Senthil

Attachment:

0 Arief Hernadi over 2 years ago in reply to senthil kumar

TI__Mastermind 23815 points

Hi Senthil,

One thing to try is to put the chip from the "suspected board" into a known good board.

If the module is working on a known good board, then it may want to check that particular PCB board.

Thanks

-Arief

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LMZM33606: Module not working