LMT01-Q1: The number of output pulses issue for LMT01-Q1

Mickey Zhang

Genius 12080 points

Part Number: LMT01-Q1
Other Parts Discussed in Thread: LMT01

Hi team,

The customer uses LMT01-Q1. He also uses SOT-92 package.

When the air temperature is 20℃, LMT01-Q1 can output 1120 pulses. But when LMT01-Q1 is in -1℃ for 2 minutes, the number of output pulses

is reduced. Finally, the number of output pulses is reduced to 0.

Please check the customer's schematic. He collects the number of the VN_1_NOT pin pulses.

the VN_1_NOT pin is connected to GPIO pin of his MCU.

The customer thinks this is abnormal when LMT01-Q1 is in -1℃ for 2 minutes.

For the customer's issue, would you provide some suggestions?

Is the customer's schematic needed to be modified?

Best Wishes,
Mickey Zhang
Asia Customer Support Center
Texas Instruments

over 6 years ago

0 Kelvin Le THS over 6 years ago

TI__Expert 6725 points

Mickey,

Do you mean LMT01 in the TO-92 package?

You're saying that when T=20C the device operates normally but when T = -1C the pulses count reduces to 0 after 2min? Does it work at other temperatures like -20C and 100C etc.

The schematic is fine. How many devices have they tested and observed this behavior? Have the customers used this device before? Is this a new design?

Have they verified this with an oscilloscope? What is the supply voltage? Please show me the scope measurement at VN_1 and VN_1_NOT when T=-1C.

-Kelvin

0 Mickey Zhang over 6 years ago in reply to Kelvin Le THS

TI__Genius 12080 points

Hi Kelvin,

1. Yes, the customer uses TO-92 package. The IC number is LMT01-Q1.
2. Yes, when T=20C the device operates normally but when T = -1C the pulses count reduces to 0 after 2min.
3. This is a new design.

For other questions, I will confirm with the customer. Then I will update the post.