LMR14030-Q1: EN Resistors

tateo yamashiro

Part Number: LMR14030-Q1

Hi,

We got a question from the customer about LMR14030-Q1.
Could you help us?

[Question]
They are considering using two LMR14030-Q1. But they need compact layout. Therefore they are considering 2 type of EN resistors circuit. They want to use either one. Please refer to below circuit. Are there any concerens about these circuit?

Best Regards,
tateo

over 7 years ago

0 Gavin Wang (Zejing) over 7 years ago

TI__Expert 3480 points

Both of two are OK.

0 Vental Mao over 7 years ago

TI__Expert 5745 points

If the divider resistor is far away from the IC, type 1 is better.

If the resistors are closed to both IC, type 2 is better.

0 tateo yamashiro over 7 years ago in reply to Vental Mao

Guru 10890 points

Hi, Vental-san
Thank you for your reply. Let me confirm one thing. Could you tell me why type 1 and type 2 is related to the position of the divider resistors?

Best Regards,
tateo

0 tateo yamashiro over 7 years ago in reply to Vental Mao

Guru 10890 points

Hi, Sorry to bother you again. They estimated Rent and Renb on Type 1 and Type 2. Please refer to below figure. Could you please double-check thier equation, correct or not?

Best Regards,
tateo

0 Vental Mao over 7 years ago in reply to tateo yamashiro

TI__Expert 5745 points

long wire as antenna will introduce some niose which may triggle the EN .

for the type 1 and type 2, the equation is right

0 tateo yamashiro over 7 years ago in reply to Vental Mao

Guru 10890 points

Hi, It has been long time since we last contacted each other.

Our customer made prototype based on the equation of Type 1. But the start/stop voltage is difference between the caluculation result and the measured value. They reconsidered the equation. Could you check whether the below figure is correct or not?

Best Regards,
tateo

0 Andy Chen over 7 years ago in reply to tateo yamashiro

TI__Mastermind 33935 points

See below the correct equation, assume the two chip has same EN threshold and current

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LMR14030-Q1: EN Resistors