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TPS62203: Max. input voltage

Part Number: TPS62203
Other Parts Discussed in Thread: TPS62745, , TPS62172, TPS62160, TPS62120

Hi,

the recommended input range of this device is 2.5-6V. Absolute maximum is 7V.

Would you say it is safe to connect 4 CR2032 batteries, two in parallel, so 6V nominal voltage to this device input? Should I be worried about voltage spikes at input capacitor? Should I use low ESR caps or that isn't enough to prevent input voltage spikes?

Do you have any better solution for that input range, 3.3V output, 100mA output current. The smaller the number of external components, the better.

  • And also, what is the max. voltage at EN pin? Max. voltage column in datasheet is empty. Is then max. voltage considered as Vin?
  • Hi SR,

    No, these 5Vin and 6Vin devices are not recommended for 2x coin cell applications, as the battery voltage can easily go above 3V over temperature, etc.

    Please see the TPS62745 which was designed for exactly these types of low power applications.

    Finally, the TPS62203 is very old. I'm curious how you found it.
  • Thank you Chris,

    actually I saw the TPS62745 before but was concerned how I was going to solder WSON package as this is a hobby project.
    I will use either:
    - TPS62745 in WSON-12
    - TPS62172 in WSON-8
    or TPS62160 in VSSOP package.

    I don't need very high efficiency at low current (cca. 10uA) as the IC will be in shutdown mode most of the time. The IC you suggested is probably the best solution because of the very low shutdown current of only 130nA.

    Thank you for your help.

    Kind regards
  • Yes, if you need a leaded device for easiest hand soldering, there is TPS62160 and TPS62120.
  • I will go with the TPS62745 as it also has VIN_SW pin so it suits very well in my project.

    Please confirm me that letting EN_VIN_SW pin floating while EN pin is pulled low is OK. I couldn't find any mention of this situation in datasheet but from the block diagram the output VIN_SW is enabled only if the EN pin is high and VIN is above UVLO threshold and of course EN_VIN_SW is high. If I got that correctly. So this situation shouldn't cause any problems, right? I can't put pull down resistor on EN_VIN_WS pin as that pin is toggled by MCU and I got other stuff connected to it.

  • Hi SR,

    Yep, we thought the Vin switch would be a good feature for this type of IC.

    It is generally not recommended to leave any digital input floating. Can you put a large value (~10M) pull-down resistor on the pin?
  • Actually, I could put a pull down there no problem. I was just in a hurry when picturing the scenario in my head.

    Please see the attached. I use GPIO from MCU to power Bluetooth module and enable VIN_SW output.

    Sch

  • Yes, that's the type of pull down I imagined.

    However, 10k is quite strong and will draw some current when that net is high. A 1Meg Ohm would be a more usual value.