LM5166: Selecting a current limit

bbrienzo

Part Number: LM5166

Hi,

As I understand it, there are discrete current limit thresholds on the LM5166. The datasheet gives specific resistor values to connect to the ILIM pin to select one of them. What is the tolerance on those resistor values? If I wanted the 300mA out limit, for example, would I be okay using a 50k resistor? What would be the dangers of not using the exact values?

Ben

over 3 years ago

0 Andy Chen over 3 years ago

TI__Mastermind 27045 points

Hi,

Tolerance 1% is OK.

For 300mA at OCT mode, the Rlim should be open or >=100Kohm

B R

Andy

0 bbrienzo over 3 years ago in reply to Andy Chen

Prodigy 90 points

Sorry I didn't clarify, I'm running the chip in PFM mode. If I want 300mA out how close to the 56.2k do I need to be? Will a 50k work? I didn't see any spec's or explanation for how the Ilim selection works.

Ben

0 Andy Chen over 3 years ago in reply to bbrienzo

TI__Mastermind 27045 points

Hi,

For the first three options (0, 24.9K and 56.2K), there is enough margin to use 20% resistor. For the 100kOhm option, using 20% resistor will give very small margin. It is better to leave it open or use 120kohm resistor.

B R

Andy

Power management

Power management forum

LM5166: Selecting a current limit