A8181
AiT Semiconductor Inc.
www.ait-ic.com
36V, 1.2A LED STEP-DOWN
HIGH BRIGHTNESS LED DRIVER WITH INTERNAL SWITCH
DESCRIPTION
FEATURES
Simple low parts count
Internal 36V NDMOS switch
Up to 1.2A output current
Single pin on/off and brightness control using
DC voltage or PWM
Soft Start
High efficiency (up to 97%)
Wide input voltage range: 6V to 36V
Output shutdown
Up to 1MHz switching frequency
Inherent open-circuit LED protection
Typical 3% output current accuracy
High-side current sense
Hysteretic control: no compensation
Adjustable constant LED current
Over temperature protection
Available in SOT-25 package
The A8181 is a continuous mode inductive step-down
converter, designed for driving single or multiple
series connected LEDs efficiently from a voltage
source higher than the LED voltage. The device
operates from an input supply between 6V and 36V
and provides an externally output current up to 1.2A.
Depending upon supply voltage and external
components, this can provides up to 24 watts of
output power.
The A8181 includes the output switch and a high-side
output current sensing circuit, which uses an external
resistor to set the nominal average output current.
APPLICATIONS
Output current can be adjusted by applying an
external control signal to the 'ADJ' pin. The ADJ pin
will accept either a DC voltage or a PWM waveform.
During DC dimming, this will provide a continuous
output current that is proportional to the external
applied DC voltage. During the PWM dimming, this
will provide a gated output current and the average
current is proportional to the duty cycle. Applying a
voltage of 0.2V or lower to the ADJ pin turns the
output off and switches the device into a low current
standby state.
Low voltage halogen replacement LEDs
Automotive lighting
Low voltage industrial lighting
LED back-up lighting
Illuminated signs
LCD TV backlighting
TYPICAL APPLICATION
The A8181 is available in SOT-25 Packages.
ORDERING INFORMATION
Package Type
SOT-25
Part Number
A8181E5R
A8181E5VR
E5
V: Green Package
R : Tape & Reel
Note
AiT provides all Pb free products
Suffix ꢀ V ꢀ means Green Package
REV1.0
- APR 2011 RELEASED -
- 1 -