LTM8040_15 Datasheet, PDF (1/20 Pages) Linear Technology – 36V, 1A Module LED Driver and Current Source

LTM8040
36V, 1A µModule
LED Driver and Current Source
FEATURES
n _{True Color PWM™ Delivers Constant Color with}
250:1 Dimming Ratio
n _{Wide Input Range: 4V to 36V}
n _{Up to 1A LED Current}
n _{Adjustable Control of LED Current}
n _{High Output Current Accuracy is Maintained Over a}
Wide Range from 35mA to 1A
n _{Open LED and Short-Circuit Protection}
n _{Grounded LED Cathode Connection}
n _{Small Footprint (15mm × 9mm × 4.32mm)}
Surface Mount LGA Package
APPLICATIONS
n _{Automotive and Avionic Lighting}
n _{Architectural Detail Lighting}
n _{Display Backlighting}
n _{Constant Current Sources}
L, LT, LTC, LTM, μModule, Linear Technology and the Linear logo are registered trademarks
of Linear Technology Corporation. True Color PWM is a trademark of Linear Technology
Corporation. All other trademarks are the property of their respective owners.
DESCRIPTION
The LTM^®8040 is a fixed frequency 1A step-down DC/DC
μModule^® regulator designed to operate as a constant cur-
rent source. Internal circuitry monitors the output current
to provide accurate current regulation, which is ideal for
driving high current LEDs. High output current accuracy
is maintained over a wide current range, from 35mA to
1A, allowing a wide dimming range over an output volt-
age range of 2.5V to 13V. Unique PWM circuitry allows a
dimming range of 250:1, avoiding the color shift normally
associated with LED current dimming.
With its wide input range of 4V to 36V, the LTM8040 regu-
lates a broad array of power sources, from 4-cell batteries
and 5V logic rails to unregulated wall transformers, lead
acid batteries and distributed power supplies.
The LTM8040 is packaged in a thermally enhanced,
compact (15mm × 9mm × 4.32mm) molded land grid
array (LGA) package suitable for automated assembly
by standard surface mount equipment. The LTM8040 is
Pb-free and RoHS compliant.
TYPICAL APPLICATION
V_IN*
11.5V TO 36V
1A μModule LED Driver
1μF
215k
650kHz
V_IN
SHDN
LEDA
LPWR
LTM8040
ADJ
BIAS
PWM
RT
GND
*RUNNING VOLTAGE. SEE APPLICATION INFORMATION
FOR START-UP REQUIREMENTS
TWO WHITE LEDs
6V TO 9V
1A
8040 TA01
Efficiency
100
90
80
70
60
50
40
30
20
V_IN = 12V
TWO 3.3V AT 1A LEDs
10 ^{OUTPUT CURRENT ADJUSTED}
WITH ADJ VOLTAGE
0
0
200 400 600 800
OUTPUT CURRENT (mA)
1000
8040 TA01b
8040fa
1