Hi Teritama,
There can be certain application scenarios where the negative rail can get pulled positive by the load before the charge pump is turned on. This is because of the load connected to the negative rail. Section 8.4.1 of the datasheet of TPS60400…
Hi Ryan,
That's basically correct. There is essentially some minimum voltage drop across the charge pump, due to the PFM mode and losses. You can see figures 5 and 8 in the LM2776 D/S.
Your application probably doesn't need -5.0V. -4.9V is likely…
Hi,
I had a short discussion with my team internally and here are some suggestions.
- There has been startup issues with this device in the past. Since you try to power using Arduino board, this may be causing an issue with too much source impedance…
Hello,
I am moving this post to the High Speed forum since the ADA4807-2 is a high speed device by Analog Devices.
For help with the TPS60400 device I recommend posting a question to the Non-Isolated DC/DC forum .
Thank you,
Tim Claycomb
Hi Jonathan,
Yes. As mentioned in the D/S, lower ESR gives better performance.
However, please see newer devices like the TPS60400 and LM2776 which are designed to use ceramic caps and have lower output impedance and require smaller capacitances…
Other Parts Discussed in Thread: TPS60400 , LM2664 I am going to possibly use TPS60400 in a design to provide the negative rail to an op amp for a bipolar output. My design is very space sensitive, and I would like to know if the input capacitor is needed…
Hi Hirano,
The OUT- startup of the LM2776 may also be affected by the positive pre-biased voltage. An external Schottky diode can be added to the OUT- pin to discharge a positive voltage on this pin.
For your reference TPS6040x has an integrated Schottky…
If you are asking about a specific part, please begin the title of your post with the part number.
LM2787 is 'active' status, which means it is still available.
How much output current do you need? There is also TPS60400 family.
Hi
I suppose it's caused by the quiescent current of TPS60400. here is my thought, for tps61200, it's not a true shutdown device, that means even though EN pin is pulled low, the backgate diode of high side MOS will conduct when Vout drops below Vin…
