LP87524J-Q1: LP87524J-Q1 Without I2C communication

Blindu Marcel

Part Number: LP87524J-Q1
Other Parts Discussed in Thread: IWR6843AOP,

I delevop a PCB with IWR6843AOP a I want to use LP875224J-Q1 to power it without I2C communication. The schematic are the following

I have the following question about this IC:

1. The size of Input Capacitor and Output Capacitor need to be at least 0805 o it could be 0402?

2. If we dont use I2C protocol communication how we can power on and power off the different output voltages? using RST signal o one of EN1, EN2 o EN3?

3. In this configuration what date can we receive in INT pin? and in the PGOOD pin?

over 2 years ago

+1 Conner Gillette over 2 years ago

TI__Genius 13880 points

1. More important than the size of the capacitor is its voltage rating and ESR. As long as you stick to a X7R or X7T, and the appropriate voltage rating, as listed in section 8.2.1 of the datasheet, you should be fine.

2. The OTP settings for this device are configured to have EN1 control all bucks. Without I2C communication, you would be unable to reconfigure this.

These tables are located in the Technical Reference Manual.

Kind regards,

Conner Gillette

0 Blindu Marcel over 2 years ago in reply to Conner Gillette

Intellectual 325 points

Thank you for aclaration.

But we can use the NRST signal instead of EN1 to switch on or switch off?

Best regards

+1 Conner Gillette over 2 years ago in reply to Blindu Marcel

TI__Genius 13880 points

Yes, you can turn on the PMIC using NRST. Setting it to high initiates power-on-reset (POR), OTP reading and enables the system I/O interface.

From 7.3.6 of the datasheet:

"If VANA supply voltage falls below UVLO threshold level or NRST signal is set low then all the regulators are disabled immediately, and all the register bits are reset to the default values. When the VANA supply voltage rises above UVLO threshold level AND NRST signal rises above threshold level an internal power-on reset (POR) occurs"

Kind regards,

Conner Gillette

0 Blindu Marcel over 2 years ago in reply to Conner Gillette

Intellectual 325 points

Then summarized to turn on and turn off LP87524J-Q1 without I2C communication we can use the EN1 signal or NRST signal?

Best regards

+1 Conner Gillette over 2 years ago in reply to Blindu Marcel

TI__Genius 13880 points

The NRST initiates a power-on reset, while the EN1 pin only enables and disables the buck, while not initiating a power-on reset.

Kind regards,

Conner Gillette

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LP87524J-Q1: LP87524J-Q1 Without I2C communication