LM2587: Step up of 35V

Ruben Quesada

Part Number: LM2587
Other Parts Discussed in Thread: LM5157, LM5155

Tool/software:

We are working with LM2587ADJ some years to do step up of 35V.

We want to find a more modern replacement that will allow us to reduce the capacity of the input and output capacitors as well as reduce the size of the coil.

Design features:

Vin 15V to 30V
Vout 35V
Iout 3A. Inside 3A has pulses of 1A 200 microseconds

over 1 year ago

0 Niklas Schwarz over 1 year ago

TI__Mastermind 30260 points

Hi Ruben,

Thanks for using the e2e forum.
The most modern replacement for this application is the LM515x family.

LM5157 is a converter with integrated FET just like LM2587.
Input voltage rating is 45V, which is within spec of this design.
The device can support a peak inductor current of 6.5A before entering overcurrent protection.

Under worst case conditions (Vin 15V, Iout 3A), there might be currents that would go above the 6.5A threshold. If this is a common operation mode, I would recommend to use a controller with external FET instead. The according device would be LM5155.

Please let me know if there are any additional questions on either device.

Best regards,
Niklas

0 Ruben Quesada over 1 year ago in reply to Niklas Schwarz

Prodigy 10 points

Can you suggest me a evaluation board of LM5155 to test my configuration?

0 Niklas Schwarz over 1 year ago in reply to Ruben Quesada

TI__Mastermind 30260 points

Hi Ruben,

Yes, we have EVMs for each device.
For LM5155, I would suggest this one:
https://www.ti.com/tool/LM5155EVM-BST

Vout is set to 24V per default, but with some small modifications, you can set the output to 35V.

Best regards,
Niklas

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LM2587: Step up of 35V