TPSM365R6FEVM: TPSM365R6FEVM

Gurmeet Singh

Part Number: TPSM365R6FEVM
Other Parts Discussed in Thread: XTR115, TPS54062, LMR36503,

We are developing a 2 wire pressure transmitter using low power Pressure Sensor with 24V DC, loop powered having output of 4-20 mA.

Sensor works at 3.3v and consumes 2 mA.

Other associated circuit consumes another 1.5 mA.

We decided to use XTR115. Unfortunately, it is not able to take load of input circuitry and with zero signal. it is giving approx. 7mA output on loop with 24V DC power connected.

Started reading more about this phenomenon and came across your (TI) application note which suggested using XTR115 with TPS54062 EVM.

When I wanted to order for TPS54062 EVM, on that device page, I found a note :

" newer version of this product is available.

Same functionality with different pin-out to the compared device, LMR36503

3-V to 65-V, 0.3-A ultra-small synchronous buck converter with 6 μA IQ Smaller footprint, lower IQ and lower EMI."

Accordingly, I ordered for TPSM365R6FEVM wherein in specification sheet you claim Iq of 4uA.

Whereas, when we connect this EVM to 24VDC, with voltage selection jumper set to 3.3v, without connecting any load, this unit is drawing 7.7 mA with Input voltage set to 24V DC.

This is not as per your claims in the specification sheet.

Please note that we purchased this unit directly from TI vide Invoice No.

5930564684 dated 26th July, 2023 and was delivered to us just few days back.

We have contacted TI support team bust so far have not got any reply in resolving this issue.

I once again request you to kindly let help in resolving this problem.

Thanks & regards,

Gurmeet

over 2 years ago

0 Youhao Xi over 2 years ago

TI__Guru* 78190 points

Hi Gurmeet,

Thank you for using our products. I am afraid there is a misunderstanding about the Iq.

In the datasheet, it says the 4uA is related to the fixed voltage version.

And 3.3V version has a specific part number (highlighted), while the EVM has adjustable Vout version (circled).

With the fixed output version, the FB resistors are integrated and it takes very little current. On the EVM it uses external resistor divider and takes higher current.

Also the EN branch on the EVM also takes current from VIN. You may consider to remove the bottom resistor to break the leak path, too.

Hope this clarifies.

Best Regards,

Youhao

0 Emil Yordanov over 2 years ago in reply to Youhao Xi

Prodigy 90 points

Hello Youhao Xi

So what is the ISUPPLY Input supply current when in regulation for the ajustable version ?

Regards,
Emil

0 Denislav Petkov over 2 years ago in reply to Emil Yordanov

TI__Mastermind 19891 points

Hello Emil,

Do you have any specific input and output voltage conditions? Any standby load current or is the output open?

PFM or FPWM mode at light load (I assume you are interested in PFM)?

We can check on the evaluation board based on your requirements.

Regards,

Denislav

0 Emil Yordanov over 2 years ago in reply to Denislav Petkov

Prodigy 90 points

Hello Denislav,

Yes, the condition are:
Vin=22..52V
Vout=7.2V
Iout=40µA

Yes, I am interested in PFM, but will be good to know for FPWM too.

Thanks in advance!
Regards,
Emil

0 Denislav Petkov over 2 years ago in reply to Emil Yordanov

TI__Mastermind 19891 points

Thank you Emil for the conditions.

We will plan to modify a board for this output voltage and gather some bench data for you.

We will target the end of the week.

Regards,

Denislav

0 Emil Yordanov over 2 years ago in reply to Denislav Petkov

Prodigy 90 points

Thank you very much Denislav,
could you please check and the VCC, I am concerned because I mesure 3.32V which seems to be out of the spec.

Kind regards,
Emil

0 Denislav Petkov over 2 years ago in reply to Emil Yordanov

TI__Mastermind 19891 points

Hi Emil,

Yes, we can check Vcc.

Regards,
Denislav

0 Denislav Petkov over 2 years ago in reply to Denislav Petkov

TI__Mastermind 19891 points

Hello Emil,

We don't have boards on hand in our local lab so we had to order some for this test.

We will most likely get them mid-next week and would expect to have data after that. Just wanted to update you on the expected time line.

Can you please confirm the end application for your project?

Regards,

Denislav

0 Emil Yordanov over 2 years ago in reply to Denislav Petkov

Prodigy 90 points

Thank you!

0 Denislav Petkov over 2 years ago in reply to Emil Yordanov

TI__Mastermind 19891 points

No problem, hopefully we can provide some data next week.

0 Carol Zhang over 1 year ago in reply to Emil Yordanov

TI__Prodigy 490 points

Hi Emil,

Thank you for your patience. We have received boards and will collect Iq and VCC bench data for you. Is there a specific switching frequency you are interested in?

Regards,
Carol

0 Carol Zhang over 1 year ago in reply to Carol Zhang

TI__Prodigy 490 points

Hi Emil,

We collected the data at a switching frequency of 1000kHz (closest selectable option on EVM for your output voltage of 7.2V from Table 9-1 in the datasheet).

The input current at a load of 40uA for PFM and FPWM (device switching and in regulation) are as follows:

	PFM	FPWM
Vin (V)	Input Current (mA)	Input Current (mA)
22	0.192	11.60
24	0.199	11.71
26	0.207	11.78
28	0.215	11.84
30	0.223	11.88
32	0.230	11.91
34	0.238	11.94
36	0.247	11.96
38	0.256	11.98
40	0.264	12.00
42	0.272	12.04
44	0.280	12.05
46	0.290	12.08
48	0.299	12.10
50	0.309	12.15
52	0.318	12.17

VCC:

PFM VCC = 3.18V
FPWM VCC = 3.32V

Note that the spec for VCC in the datasheet applies to auto mode.

Let us know if you need anything else!

Regards,
Carol

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TPSM365R6FEVM: TPSM365R6FEVM