LMR36503-Q1: Switching Frequency at Vin_max condition

NOBUO FUJIHARA

Genius 9335 points

Part Number: LMR36503-Q1

Hi team,

Attached is the Webench result, and I would like to confirm if Fsw is kept 2MHz with max Vin and 100mA load.

- Vin range : 24V to 58V

- Vout = 12V

- Iout=100mA

From duty cycle vs Iout graph, can I think Fsw is kept 2MHz when Vin =58V and Iout=100mA?

Best regards,

LMR36503MSC WBDesign339.pdf

over 4 years ago

0 iAlejandro over 4 years ago

TI__Expert 8130 points

Hello Nobuo,

From the shared design, you are using the Fixed Fsw option of 2.2MHz.
If a fixed fsw of 2 MHz is desired, then I would recommend to sync the device to an external clock. While the device is in SYNC mode, it operates as though in FPWM.

Regards,
Alejandro

0 NOBUO FUJIHARA over 4 years ago in reply to iAlejandro

TI__Genius 9335 points

Hi Alejandro,

Thanks for the comment about SYNC mode.

Can you check if device can keep Fsw=2MHz under below condition?

- Vin=59V

- Vout=12V

- Iload = 100mA

- L=120uH

regards,

0 iAlejandro over 4 years ago in reply to NOBUO FUJIHARA

TI__Expert 8130 points

Nobuo,

Yes, the device will operate in FPWM at 2MHz. The operating conditions do not violate the minimum on-time conditions and the device will therefore maintain at a 2-MHz switching frequency even at light loads.

Regards,
Alejandro

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LMR36503-Q1: Switching Frequency at Vin_max condition