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Renesas Electronics Europe - Knowledgebase

How to properly operates UPC1100 or 1150 switching regulator device?

Latest Updated:11/01/2005


My UPC1100 or 1150 switching regulator device sometimes operates and sometimes doesn't.


The timer latch circuit may be malfunctioning. Check the following.

  • Is there any incorrect wiring?
  • The GND wiring can sometimes be a cause of malfunction. Make sure that the GND pins for signal lines and power lines are separate, and that each is grounded to a separate point.
  • Is there a capacitor connected between the REF OUT pin (pin 16) and GND pin (pin 8)? If so, be sure to use a film, tantalum, or ceramic capacitor.
  • Be sure to ground the GND side of the delay capacitor CDLY connected to the DLY pin (pin 15) as close as possible to the GND pin (pin 8).
  • When using the ON/OFF control pin (pin 4), ensure that the signal input to this pin rises at no more than 0.07V/us.
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Power Management Linear