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Features
Excellent LED Drive Capability:
3 LED String: 30mA
4 LED String: 20 mA
6 LEDs (2 strings of 3): 15 mA
Very High LED Drive Efficiency: > 80%
Low Feedback Voltage: 515mV
Low-Resistance NMOS Power Switch: 0.6Ω
High-Speed PWM Brightness Control Capability
Over-Voltage Protection (18V min, 19V typ, 20V max)
Inrush and Inductor Current Limiting
2.3V - 7V Input Voltage Range
Requires Only a Few External Components
No External Compensation Needed
Programmable Oscillator Frequency
ON/OFF Pin
Small SOT23-8 Package
Description The LM2707 is a magnetic boost regulator specifically designed for white LED drive applications. Tightly regulated LED currents,
exceptional LED brightness uniformity, and very high LED-drive power efficiency (>80%) can all be achieved by stacking the
LEDs in series between the LM2707 output and the low-voltage feedback pin (0.515V).
The LM2707 requires only a few small external components. A small inductor with a low saturation current rating can safely
be used because the tightly controlled current limit circuit prevents large inductor current spikes, even at start-up. The
output capacitor can also be small due to the tightly controlled output over-voltage protection circuit.
The LM2707 is an excellent choice for display backlighting and other general-purpose lighting functions in battery powered
applications. The 2.3V-to-7V input voltage range of the device easily accommodates single-cell Lithium-Ion batteries and battery
chargers.
The LM2707 features 18V output capability, PFM regulation, and a high-current switching transistor (400mA peak). These characteristics
allow the part to drive a series string of 2-to-4 LEDs with forward currents between 0 and 40mA. LED brightness can be adjusted
dynamically simply by applying a PWM signal to the enable (EN) pin. The PWM signal can be as fast as 50kHz because the LM2707
has a fast turn-on time.
In addition to LED-drive applications, the LM2707 can also be used as a general purpose DC-DC voltage regulator in boost converter
applications.
The LM2707 is available in a SOT23-8 surface mount package.
Applications
White LED Drive for Display Backlights
LED Flashlights
General Purpose LED Lighting
Step-up DC/DC Voltage Conversion
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