LM3489-Q1: Request to check the circuit

Tomoyuki Taguchi

Prodigy 100 points

Part Number: LM3489-Q1
Other Parts Discussed in Thread: PSPICE-FOR-TI

I would like you to check the circuit.

Input voltage: 5 V, 9 V, 15 V, 20 V

Output voltage: 5V, 9V, 15V, 20V

Output current: 3A (MAX) It is designed according to the circuit diagram of TPS65988EVM.

However, use a ceramic capacitor for the output capacitor. I checked "8.2.2.2 Output Capacitor Selection (COUT)", It says that you have to insert a series resistor, Where and how many Ω resistance values should I put in?

over 3 years ago

0 Jimmy Hua over 3 years ago

TI__Guru 50120 points

Hi,

You can put a single resistor in series with the output capacitor C1003. Then you can control the the resistor value in series with that bulk output capacitor to the desired value.

Make sure to properly verify and validate the circuit.

Regards,

Jimmy

0 Tomoyuki Taguchi over 3 years ago in reply to Jimmy Hua

Prodigy 100 points

Dear Jimmy

Thank you for your answer.
"PSPICE-FOR-TI — PSpice® for TI design and simulation tool"
I am running a simulation with the downloaded schematic using.
The "ISENS" connection is connected to the FET sauce.
In the data sheet and evaluation board, it is connected to the drain of the FET, so if you reconnect it as it is, it will not operate normally.
Is this a simulation glitch?
Which connection is correct?

0 Jimmy Hua over 3 years ago in reply to Tomoyuki Taguchi

TI__Guru 50120 points

Hi,

From initially inspection, it looks like the PSPICE schematic is incorrect.

The ISENSE resistor should be connected to the drain of the PFET terminal as shown in the evaluation board.

Regards,

Jimmy

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LM3489-Q1: Request to check the circuit