www.DataSheet4U.com
AME, Inc.
AME5138
n General Description
The AME5138 is a fixed off-time step-up DC/DC converter in ...
www.DataSheet4U.com
AME, Inc.
AME5138
n General Description
The AME5138 is a fixed off-time step-up DC/DC converter in a small 5-lead SOT-25 package.The AME5138 is ideal for LCD panels requiring low current and high efficiency as well as LED applications for cellular phone backlighting, PDAs,and other hand-held devices. The low 400ns off-time allows the use of tiny external components. AME5138 is designed to drive up to four white LEDs in series with a constant current from a single Li-lon battery. 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 under
voltage 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
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AME,...