AAT3124

High Efficiency 1x/1.5x Fractional Charge Pump for White LED Applications


Please note: this product is being discontinued and is not recommended for new designs.

The AAT3123/24 is a low noise, constant frequency charge pump DC/DC converter that uses a dual mode Load Switch (1X) and fractional (1.5X) conversion to maximize efficiency for white LED applications. The device can be used to produce current levels up to 20mA to drive up to six (6) LEDs from a 2.7V to 5.5V input. Outputs may be operated individually or paralleled for driving higher-current LEDs. Low external parts counts (two 1µF flying capacitors and two small 1µF capacitors at VIN and OUT) make the AAT3123/24 ideally suited for small battery-powered applications.

AnalogicTech’s Simple Serial Control™ (S²Cwire™) interface is used to enable, disable, and set the LED drive current with a 32-level logarithmic scale LED brightness control. The AAT3123/24 has a thermal management system to protect the device in the event of a short circuit condition at the output pin. Built-in soft-start circuitry prevents excessive inrush current during start-up. A high charge pump switching frequency enables the use of very small external capacitors. A low current shutdown feature disconnects the load from VIN and reduces quiescent current to less than 1mA.

The AAT3123 is available in very small 12-pin TSOPJW package, and the six-output AAT3124 is available in a 16-pin 4x4mm QFN package.

Please note: AAT3124 is not recommended for new designs.

Specifications

Number of LEDs6
LED Channels6
LED(s) per/Ch1
Min. VIN (V)2.7
Max. VIN (V)5.5
InterfaceS2Cwire™
Typ. IQ (μA)1800
Peak Efficiency93%
Current Accuracy (%)±10%
Current Matching (%)±0.5%
Max. IOUT per/Ch (mA)20
Package (mm)4 x 4
PackageTSOPJW-14, QFN44-16

Features

  • VIN Range: 2.7V to 5.5V
  • Dual Mode 1X and 1.5X Charge Pump for Maximum
  • Efficiency
  • Drives Low-VF and High-VF Type LEDs
  • Up to Six 20mA Outputs (AAT3124)
  • Up to Four 20mA Outputs (AAT3123/23A)
  • 32-Position Logarithmic Scale with Digital Control
  • Simple Serial Control (S²Cwire) Interface
  • Low Noise Constant Frequency Operation
  • 1MHz Switching Frequency
  • Small Application Circuit
  • Regulated Output Current
  • Automatic Soft Start
  • No Inductors
  • IQ < 1μA in Shutdown
  • Temperature Range: -40°C to +85°C
  • 12-Pin TSOPJW Package (AAT3123/23A)
  • 16-Pin 4x4mm QFN and 14-Pin TSOPJW Packages (AAT3124)

Product Documents