MAX1574ETB-T

Product Summary

The MAX1574ETB-T 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 MAX1574ETB-T uses an external resistor to set the fullscale 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 MAX1574ETB-T maintains constant LED current as long as EN is kept high. If EN is kept low for more than 2ms, the MAX1574ETB-T enters shutdown. The MAX1574ETB-T is available in a 10-pin 3mm x 3mm TDFN package (0.8mm max height).

Parametrics

MAX1574ETB-T absolute maximu mratings: (1)IN, OUT, EN to GND: -0.3V to +6.0V; (2)SET, LED1, LED2, LED3, CN to GND: -0.3V to (VIN + 0.3V); (3)CP to GND: -0.3V to; (4)the greater of (VOUT + 1V) or (VIN + 1V) OUT Short Circuit to GND: Continuous; (5)Continuous Power Dissipation (TA = +70℃), 10-Pin TDFN (derate 18.2mW/℃ above +70℃): 1454mW; (6)Operating Temperature Range: -40℃ to +85℃; (7)Junction Temperature: +150℃; (8)Storage Temperature Range: -65℃ to +150℃; (9)Lead Temperature (soldering, 10s): +300℃.

Features

MAX1574ETB-T features: (1)Up to 180mA (60mA/LED) Drive Capability; (2)83% Average Efficiency (PLED / PBATT) Over Li+Battery Discharge; (3)0.5% (typ) LED Current Matching; (4)Adaptive 1x/2x Mode Switchover; (5)Low Input Ripple and EMI; (6)5% to 100% Dimming Through Single-Wire Serial Pulse Interface; (7)Low 0.1μA Shutdown Current; (8)2.7V to 5.5V Supply Voltage Range; (9)Soft-Start Limits Inrush Current; (10)Output Overvoltage Protection; (11)Thermal-Shutdown Protection; (12)10-Pin 3mm x 3mm TDFN Package.

Diagrams