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White LED 1x/1.5x Charge Pump in UCSP and Thin QFN

Smallest, Highest Efficiency White LED Charge Pump Packaged in a UCSP™

Product Details

Key Features

Parametric specs for LED Drivers
VIN (V) (min) 2.7
VIN (V) (max) 5.5
Max. No. of LEDs 4
# LED Channels 4
Regulation Topology Charge Pump
Battery Input 1-Cell Li+
LED Configuration Parallel
ILED per Channel (A) (max) 0.028
PWM Dimming Freq. (kHz) (max) 50
Dimming Control Digital
PWM
POUT (W) 0.5
ICC (mA) (max) 4
LED String Volt. (V) (max) 5
Switching Frequency (kHz) 1000
Package/Pins TQFN/16
Budgetary
Price (See Notes)
2.15
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Simplified Block Diagram

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Parameters

Parametric specs for LED Drivers
VIN (V) (min) 2.7
VIN (V) (max) 5.5
Max. No. of LEDs 4
# LED Channels 4
Regulation Topology Charge Pump
Battery Input 1-Cell Li+
LED Configuration Parallel
ILED per Channel (A) (max) 0.028
PWM Dimming Freq. (kHz) (max) 50
Dimming Control Digital
PWM
POUT (W) 0.5
ICC (mA) (max) 4
LED String Volt. (V) (max) 5
Switching Frequency (kHz) 1000
Package/Pins TQFN/16
Budgetary
Price (See Notes)
2.15

Key Features

  • Proprietary Adaptive 1x/1.5x Modes
  • High Efficiency (PLEDs/PBATT), Up to 92%
  • 0.2% LED Current Matching
  • 28mA/LED Drive Capability
  • Low Input Ripple and EMI
  • Eliminates Ballast Resistors
  • Logic or PWM Dimming Control
  • Low 0.1µA Shutdown Current
  • 2.7V to 5.5V Input Voltage Range
  • Soft-Start Limits Inrush Current
  • Output Overvoltage Protection
  • Thermal Shutdown Protection
  • No External Schottky Diode Required
  • Tiny UCSP (2.1mm x 2.1mm x 0.6mm) and Thin QFN (4mm x 4mm) Packages

Applications/Uses

  • Cell Phones/Smartphones
  • MP3 Players
  • Other Handhelds with Color Displays
  • PDAs, Digital Cameras, and Camcorders

Description

The MAX1573 fractional charge pump drives up to four white LEDs with regulated constant current for uniform intensity. By utilizing proprietary adaptive 1x/1.5x modes and ultra-low-dropout current regulators, it maintains the highest possible efficiency over the full 1-cell Li+ battery input voltage range. The 1MHz fixed-frequency switching allows for tiny external components and the regulation scheme is optimized to ensure low EMI and low input ripple.

An external resistor sets the full-scale LED current, while two digital inputs control on/off and select amongst three levels of brightness. A pulse-width modulation (PWM) signal can also be used to modulate LED brightness, requiring no additional components.

The MAX1573 is available in the tiny chip-scale UCSP™ (4 x 4 grid) and 16-pin thin QFN packages.

Simplified Block Diagram

MAX1573: Typical Operating Circuit MAX1573: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .