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User's Guide
SNVA126A–February 2006–Revised April 2013
AN-1406 LM3519 Evaluation Board
1 General Description
The LM3519 evaluation board is a working demonstration of a step up DC-DC converter. The LM3519
drives up to four white LEDs with a constant current to provide LCD backlighting in handheld devices. The
LED current is internally set to 20 mA eliminating the use of external resistor. The series connection allows
the LED current to be identical for uniform brightness and minimizes the number of traces to the LEDs.
Brightness control is achieved by applying a PWM signal on the En pin with frequencies up to 30 kHz. A
proprietary PFM architecture implementation results in non pulse skipping variable frequency operation
over input voltage range permitting the use of low-cost, small external components. For further information
and electrical characteristics, see the LM3519 High Frequency Boost White LED Driver with High-Speed
PWM Brightness Control Data Sheet (SNVS394).
2 Operating Conditions
• Junction temperature (T
J
) range: -40°C to +125°C
• Ambient temperature (T
A
) range: -40°C to +85°C
• Input Voltage Range: 2.7 V to 5.5 V
• I
OUT
= 20 mA
Package
• SOT 23 - 6 pin
3 Typical Application
Figure 1. Typical Application Circuit
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SNVA126A–February 2006–Revised April 2013 AN-1406 LM3519 Evaluation Board
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