MAX1577Z White LED Regulating Charge Pump Evaluation Kit

The MAX1577Y/MAX1577Z charge pumps drive white LEDs, including camera strobes, with regulated current up to 1.2A (guaranteed to 800mA). The very low openloop output resistance allows high flash brightness, even from a low battery input voltage. The adaptive 1x/2x regulating charge-pump operation provides high efficiency (up to 92%) while in movie mode or backlighting. Fast (1MHz) switching allows the use of tiny external components. The MAX1577Y/MAX1577Z use an external resistor to set the full-scale LED current. Two enable inputs (EN1 and EN2) provide simple on/off control and LED current of 20%, 33%, or 100% full scale. If there is less than 24mV across the external resistor, the output voltage is regulated. The MAX1577Z has fixed 5.1V output-voltage regulation, while the MAX1577Y has logic-controlled output voltage of 3.4V, 4.6V, or 5.1V for backlighting, keyboard, and RGB applications. The MAX1577Y/MAX1577Z are available in an 8-pin, 3mm x 3mm TDFN package (0.8mm max height).

• Up to 1.2A Output Drive Capability (800mA Guaranteed)
• Up to 92% P_LED / P_BATT Efficiency for MovieMode
• Flexible Brightness Control
  • Two-Bit Logic for 100%, 33%, 20%, and Off
  • PWM for 20% to 100%

3% Current Regulation Over Line and Temperature

Current or Voltage Regulation for Flash and Backlighting (MAX1577Y)

Current Regulation for Flash (MAX1577Z)

Low Ripple and EMI

2.7V to 5.5V Supply Voltage Range

Soft-Start Limits Inrush Current

Output-Voltage Regulation Mode

Thermal-Shutdown Protection

8-Pin 3mm x 3mm TDFN Package