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LM5165: LM5165EVM-HD-P50A and LM5165EVM-HD-C50X

Shota Mago

Expert 7060 points

Part Number: LM5165

Hi team,

My customer is testing LM5165EVM and he provided some questions as below.

What is the reason R1(4.7kΩ) is connected in series to input capacitor(C6)?
What are the reasons why P50A and C50X have different inductance(L1) and capacitance(C4)?
In terms of 50X, why is R11(1.5Ω) connected in series to the output capacitance(C4)?

I'm looking forward to hearing back from you.

Best regards,
Shota Mago

over 6 years ago

0 Samuel Jaffe over 6 years ago

TI__Mastermind 25590 points

Shota Mago,

1. R1 is 4.7 ohms, not 4.7k. This is to add ESR to the input cap to dampen any ringing on the VIN line from transients or hot-plug.

2. P50A and C50X have different output voltages (3.3V and 5V). Different output voltages require different power components for optimal design.

3. The required ESR is a function of VOUT (see eq 15 in the datasheet). 5VOUT may not require more ESR than is naturally in the cap.

-Sam

0 Shota Mago over 6 years ago in reply to Samuel Jaffe

TI__Expert 7060 points

Hi Sam-san

Thanks for quick reply and providing exact answer what I want.

Best regards,
Shota Mago