FTM Board Club
Fairchild Semiconductor
Programmable Indicator "Soft" LED Blinker with TinyWire™ Single-Wire Interface demo board

The FAN5646 is a flexible and compact solution for a blinking or "breathing" LED indicator.

The internal programmable blink algorithm eliminates any need for continual system processor control. This means longer battery life for a hand-held system because the system processor is not awakened from sleep mode to blink an LED. Very low dropout of 80mV allows driving an LED without any inductors or switch capacitors. LED blink rate, rise and fall time, and CTRL line behavior can be programmed by a TinyWire single-wire digital interface. The on-time and time between pulses can be set for up to two different pulse widths. The default for FAN5646 option 01 is "follow" mode, where the LED turns on with the programmed rise time, then stays on as long as CTRL remains HIGH. When CTRL falls, the LED turns off at the programmed fall time. For option 00; when CTRL is HIGH continuously, the LED repeats the programmed pattern. The FAN5646 is available in a four-pin wafer-level chip-scale package with 0.4mm pitch of a five-lead SC70 package.


LED "Soft" Blink: with Logarithmic Fade Up and Fade Down for Power Savings

  • Follow or Repeat Pattern Mode for Blinking when Applications Processor is Powered Down
  • Default Pattern Optionally Modified using TinyWire Single-Wire Digital Control for: ◦LED Current Rise/Fall Time ◦tON and tOFF for up to two pulses
  • High-Side Constant Current LED Driver: ◦20mA Maximum Output Current ◦80mV Drop-out at 20mA IOUT ◦External RSET (SC70 only) or Internal Current Programming
  • 35µA Operating Quiescent Current
  • Short-Circuit, Under-Voltage, and Thermal Protections
  • Wide Input Range: 2.7 to 5.5V
  • 4-Bump WLCSP, 0.4mm Pitch or 5-Lead SC70 (EIAJ SC88)