TPS7B7701-Q1: PSRR data @ Io=100mA, CO=2.2uF, f=100Hz

Yasushi Fujiwara

Part Number: TPS7B7701-Q1

Hello Experts,

Customer would like to know PSRR data as Figure 9 in datasheet. The condition is Io=100mA, Co=2.2uF(same as spec).

Best Regards,
Fujiwara

over 2 years ago

0 John Schneider over 2 years ago

TI__Genius 12511 points

Hi Fujiwara-san,

I can try to get this data in the lab this week for you.

Vin = 14V is ok?

What VOUT would you want.

We would expect with higher IOUT and smaller COUT that the PSRR will be slightly lower than what is depicted in the datasheet figure.

Regards,

John

0 Yasushi Fujiwara over 2 years ago in reply to John Schneider

TI__Genius 12725 points

Hi John-san,

The condition is as follows.

- Input voltage: 14.4V
- Output voltage: 8V
- Iout: 100mA
- Input capacitor: 10uF x 2pcs series(5uF) or 4.7uF
- Output capacitor: 47uF(Electrolytic capacitor)+0.1uF

Best Regards,
Fujiwara

0 John Schneider over 2 years ago in reply to Yasushi Fujiwara

TI__Genius 12511 points

Thanks Fujiwara-san,

I will get you this data as soon as I'm able to take it!

Regards,

John

0 Yasushi Fujiwara over 2 years ago in reply to John Schneider

TI__Genius 12725 points

Hi John-san,

Do you have a time to take the data? Customer is waiting this data.

Best Regards,
Fujiwara

0 John Schneider over 2 years ago in reply to Yasushi Fujiwara

TI__Genius 12511 points

Hi Fujiwara-san,

I've been testing it all today, but I'm having trouble reducing noise and erroneous spurs in the measurement itself causing the graph to not be nice enough to share out with customer, specifically relating to inductance on the cables as I am using an EVM, and have to introduce inductive clips and cables in order to take the measurement.

However I can tell you at rough approximations of the rejection ratio at some points along the curve for the portions of the curve that the parasitics have not affected

10Hz - 70dB

100Hz - 72dB

1000Hz - 63dB

10000Hz - 30dB

100kHz - 52dB

1MHz - 22dB.

The rest of the curve I do not trust to be representative of the LDO's actual operation.

Regards,

John

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TPS7B7701-Q1: PSRR data @ Io=100mA, CO=2.2uF, f=100Hz