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PMIC for P2 boards? — Parallax Forums

PMIC for P2 boards?

Anybody think a Power Management ICs is a good idea for P2 boards?
Is it overkill? Maybe...

I'm looking at the MAX77714 right now...

Unfortunately, most of the PMICs I've found, the above included, target a core voltage <1.8 V.
But, this one has several buck converters and we could just not use the low voltage one.

What's nice is that it also has an RTC (that doesn't need a crystal) and a WatchDog timer.

There are some simpler ones like this: TPS65053

But, I haven't found one that's a perfect fit for 1.8V core yet... Anybody know of a better option?

Comments

  • jmgjmg Posts: 15,140
    edited 2019-10-10 22:09
    For 3v3 side, I like the look of the new NCP187AMT330TAG - low noise, with power good, and compact package with good thermals for heatsink vias & low price.
    Soon to be stocked at DK & Mouser.
    Now in stock at DK, and due 22nd Mouser.
    Also in stock, as a possible '2nd BOM source' is NCV8187AMT330TAG (Automotive version 2x2 package, slightly higher price)


    1V8 selection is trickier, and can depend on what matters ? :

    * Do you need > 5V DC in, or is 5V/USB in OK
    * Do you need integrated inductor, or is external inductor ok ?
    * Do you want fine trim of VDD for power/speed trade offs ?
    * is BGA ok, or is DFN/QFN preferred ?

    Example: for 5.5V max in, and lowest cost/external inductor, in DFN package, I like the look of AP3441LSHE-7B
    My notes say :
    AP3441SHE-7B Diodes LV BUCK 2.7V~5.5V 0.6V~5.5V 3A 1MHz PGood -40°C ~ 85°C (TA) 8.2 °C/W 8-VFDFN U-DFN2020-8 2x2mm 72mΩ 52mΩ << NEW low cost $0.14603/3k

    or, if i2c and pin-select PSU flexibility are needed, this OnSemi part looks interesting, ( 1.10 VSEL should be ok for P2 RAM retention ?)
    NCV6357A 3.0 × 4.0 mm / 0.5 mm Pitch DFN 14 Package 5A 39 <60 mΩ 32 <45 mΩ 76c/3k
    • Programmable Output Voltage: 0.6 V to 3.3 V in 12.5 mV Steps 1.8V default, 1.10V VSEL in 2 order codes : NCV6357A NCV6357C
    • Up to 2.4 MHz Switching Frequency with On Chip Oscillator
    • I2C Control Interface with Interrupt and Dynamic Voltage Scaling Support
  • RaymanRayman Posts: 13,798
    I think I've decided to try out the TPS650532...

    I can actually use the 1.5 V regulator to supply power to the RTC on an FTDI chip...
  • jmgjmg Posts: 15,140
    Rayman wrote: »
    I think I've decided to try out the TPS650532...
    Could be a bit light on current, with 250 mΩ typ PFETs?

  • RaymanRayman Posts: 13,798
    Right now, I'm doing everything with USB power only, 500 mA max. This thing has 1 A for 3.3 V and 1 A for 1.8 V and 2 LDOs for an extra 600 mA of 3.3 V.
    Seems like plenty to me...
  • RaymanRayman Posts: 13,798
    Just noticed datasheet says you can use the output of one regulator to enable another, letting you stagger turn on of the supplies.
    I think usually you want the core to get power before the I/O...
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