GENERAL DESCRIPTION
To control LED brightness, the LED current can be adjusted by applying a PWM (pulse width modulated) signal with a frequency range of 100Hz to 50KHz to the EN pin. Micropower Step-Up DC/DC Converter n Typical Application V IN 2.5V-4.2V 5 V IN L 10µH 1 SW ILED COUT 1µF Ceramic D Option for 4LEDs CIN 4.7µF Ceramic AME5138 >1.1V 4 EN 0V GND 2 FB 3 R2 80Ω * ILED =VFB/R2 n FEATURES
l 0.7Ω internal switch l Uses small surface mount components l Adjustable output voltage up to 20V l 2V to 5.5V input range l Input undervoltage lockout l 0.01µA shutdown current l Small 5-Lead SOT-25 package l All AME's lead free Product Meet RoHS Standard Figure 1¡G Four White LEDs Application in Li-lon Battery VIN 2.5V-4.2V L 15µ H D 20V 10mA 5 CIN 4.7µF Ceramic 4 VIN 1 SW 3 R1 200K AME5138 FB EN GND 2 COUT 1µF Ceramic R2 13K n APPLICATIONS
l l l l l White LED Back-Lighting Hand-held Devices Digital Cameras Portable APPLICATIONS
LCD Bias Power Figure 2¡G Typical 20V Application 1 AME, Inc.
Analog Microelectronics
