The MAX1574ETB+T is a 180mA, 1x/2x, white LED charge pump in 10 pin TDFN package. The MAX1574 charge pump drives up to three white LEDs with regulated constant current for uniform intensity. By utilizing adaptive 1x/2x charge-pump modes and very-low-dropout current regulators, it achieves 180mA output drive capability and high efficiency over the 1-cell lithium-battery input voltage range. Fixed-frequency (1MHz) switching allows for tiny external components and the regulation scheme is optimized to ensure low EMI and low input ripple. The MAX1574 uses an external resistor to set the full-scale 100% LED current. An enable input (EN) is used for simple on/off control or can be pulsed repeatedly to set lower LED current in multiple steps down to 5%. Once the desired brightness is set, the MAX1574 maintains constant LED current as long as EN is kept high. If EN is kept low for more than 2ms, the MAX1574 enters shutdown.
Supply voltage range is 2.7V to 5.5V
Operating temperature range from -40°C to 85°C
Average efficiency is 83% (PLED / PBATT) over Li+ battery discharge
(EN)
