• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 62 subscribers
  • Views 380 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

LP38798 and LP3878-ADJ - Compatibility with Schmartboard 204-0022-01 DIP adapter?

Lior Golgher
Prodigy 130 points
Other Parts Discussed in Thread: LP38798, LP5907, LP3878-ADJ

Greetings,

I would like to suppress noise and especially ripples for the 15 Volts power supply of a sensitive detector. We currently experience detrimental ripples at ~320 kHz that are picked up by our downstream data acquisition, despite using a low-noise power source. I thought of using LP38798 voltage regulator, which can handle 15 Volts as well as the expected 50 mA currents and exhibits an impressive PSRR well into the MHz range. However, we only need a few regulated power supply units, and would like to build a prototype on an ordinary solderless breadboard.

Can you please advise whether LP38798 can be mounted on a solderless breadboard using any of the following Schmartboard DIP adapters?

http://schmartboard.com/schmartboard-ez-0-5mm-pitch-10-pin-dfn-to-dip-adapter-204-0022-01/

http://schmartboard.com/schmartboard-ez-qfn-10-and-32-pins-5mm-pitch-2-x-2-grid-202-0017-01/

Evidently these two options offer only 10 pins, but I hope legs 1 and 12 can remain unconnected given the low currents involved.

Alternatively, can you please suggest other mounting solutions, or other voltage regulators that can handle 15 Volts and are easier to mount on a breadboard?

The same question applies for a LP3878-ADJ voltage regulator which I thought of using in the same circuit, for an adjustable 0-900 mV supply with uA currents. If that won't work I'd opt for the LP5907 regulator, reducing its output voltage with a voltage divider.

Thanks in advance,
Lior

  • 0
    TI__Mastermind 22610 points

    Yes, it is possible to operate LP38798 with pin 1 and pin 12 open, although this is not supported or recommended. In the case of a dead short to ground on Vout, the bond wires on the remaining pins may not be able to handle the full short circuit current.

    For the LP38798 I might recommend the Schmartboard 0.5mm Pitch, 12 Pin DFN Adapter sku # 204-0028-01.

    The description says it is designed for 4mm x 4mm package.

    My concern with all of these is that you will need to ensure that the traces do not touch the thermal pad on the bottom of the package. I don't see trace dimensions on any of these , so I don't know. You will need to check carefully and keep a sharp x-acto knife nearby just in case.

    As for " ... ~320 kHz that are picked up by our downstream data acquisition ..." , is it possible that the downstream data acquisition is the source?

    LP3878-ADJ has two package options, while LP5907 has four package options. You should determine what you need for thermal performance to see if SOT-23, SOT-223, TO-252, SOIC, etc, might be possible. The Parametric Selection Tool at TI.com can sort on package types as well as electrical specs.