TPS7A57: Design Help

SVJS

Part Number: TPS7A57

Hi,

I am using TPS7A5701 in my project for powering ADC. I went through the datasheet and Evaluation board. I have a doubt regarding EN and CP_EN pin. In the evaluation board, these pins are connected to GND through 2M resistor. Is it required or not?

over 2 years ago

0 Edgar Acosta1 over 2 years ago

TI__Genius 12445 points

Hello,

They are actually not needed when the part is powered on, there is internal resistance to pull a floating EN or CP_EN down to GND. It’s only when the part is not powered on that EN or CP_EN truly becomes floating when not driven externally.

Best,

Edgar Acosta

0 SVJS over 2 years ago in reply to Edgar Acosta1

Prodigy 140 points

Can you please verify this circuit for Vout = 1.8V and Vin = 2.5V, Iout = 2.3A. ?

0 Edgar Acosta1 over 2 years ago in reply to SVJS

TI__Genius 12445 points

Hi,

Here are my comments.

For a Vout of 1.8V you need a 36kOhm resistor from REF to GND. Vout is set by the current at REF (50µA), therefore, Vout=50µA*36kOhms=1.8V.

Bias is not required for Vin>1.1V, however, CP_EN is required, therefore tie this to VIN, or some other rail. The device will not turn on if there is no voltage applied at this pin, hence, tying this to Vout, will not enable the device.

Make sure that the path for Vin is low impedance to minimize any IR drop due to the 2.3A load.

Best,

Edgar Acosta

0 SVJS over 2 years ago in reply to Edgar Acosta1

Prodigy 140 points

Hi,
Sorry I uploaded the wrong image. That's why it have a wrong REF value and CP_EN connection. I will share the correct circuit.
thank you for your support.

0 Edgar Acosta1 over 2 years ago in reply to SVJS

TI__Genius 12445 points

Hello,

No worries.

Let me know when the schematic is ready.

Best,

Edgar Acosta

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TPS7A57: Design Help