LP87702-Q1: Request for Advice on Pin Configuration – LP87702-Q1

Aung Chan Myint

Part Number: LP87702-Q1
Other Parts Discussed in Thread: IWR1843BOOST

Tool/software:

Dear Team,

I have designed a schematic for the LP87702-Q1 buck converter. I plan to test it in standalone operation without any digital input/ouput other than a 3.3V Vin.

My target outputs are:

1.8V from SW_B0
1.24V from SW_B1
5V from VOUT_BST

I have followed the schematic checklist (https://www.ti.com/lit/zip/snvr494).

For the pin configuration:

CLK, SDA, SCL, EN1 are tied to GND
GPO0, PG0, PG1, VMON1, VMON2 are left unconnected

For this design, and the schematics are attached below for your reference.

Could you please confirm if there is anything I might have missed?

Also, can this schematic operate under the conditions described above?

Thank you in advance for your support.

2 months ago

0 Niko Alatalo 2 months ago

TI__Mastermind 21810 points

Hi Aung,

I looking into this and will get back to you tomorrow.

regards,

Niko

0 Aung Chan Myint 2 months ago in reply to Niko Alatalo

Prodigy 40 points

Hello Niko Alatalo ,

Appreciate it. Thanks in advance.

+1 Niko Alatalo 2 months ago in reply to Aung Chan Myint

TI__Mastermind 21810 points

Hi,

please see my comments attached. The required voltages are possible. Please see this link for the technical reference manual for LP87702D.

LP8770x_schematic_layout_checklist.xlsx

regards,

Niko

0 Aung Chan Myint 2 months ago in reply to Niko Alatalo

Prodigy 40 points

Hello Niko Alatalo

Thanks for the help. I really appreciate it. I tried to update based on your advice. Which seems to only fix the connection by tying pin 19 (EN1) and pin 22 (CLKIN) to the same VANA or input 3.3 V rail.

I have also updated the attached schematic with the corrected connection. I would appreciate it if you could check it.

Additionally, I was trying to replicate the power regulation circuit of the IWR1843BOOST, which uses LM536253-Q1 → LP8770-Q1 → TPS7A5301, without any digital signal input/output, to verify the operating conditions under different load scenarios. All of the passive component values are based on the schematic design of the IWR1843BOOST.

6102.LP8770x_schematic_layout_checklist.xlsx