1.2 A Single Flash LED Driver With AS<sup>2</sup>C Interface

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

The SKY81290 is a high efficiency, 1.2 A high current boost converter with a programmable constant current sink. It is an ideal power solution for LED photo flash applications in all single cell, Li-ion powered products.

The SKY81290 maintains output current regulation by switching the internal high-side and low-side switch transistors. The transistor switches are pulse-width modulated at a fixed frequency of 2.0 MHz. The high switching frequency allows the use of a small external inductor and output capacitor, which makes the SKY81290 ideally suited for small battery-powered applications.

Skyworks proprietary Advanced Simple Serial Control (AS2Cwire™) digital interface is used to enable, disable, configure, and program the operation of the SKY81290. Using the AS2Cwire interface, the Movie Mode current level for each LED, flash safety timer, and the flash-to-Movie-Mode current ratio can be programmed to one of 16 levels.

The SKY81290 includes a separate flash enable input (FLEN) to initiate the flash operation. Also included is a flash inhibit pin (FLINH) that reduces the flash current to Movie Mode levels during high battery demand. The maximum Flash and Movie Mode current is set by one external resistor where the ratio of Flash to Movie Mode current is set at approximately 7:1.

The SKY81290 contains a thermal management system to protect the device in the event of an output short-circuit condition. Built-in circuitry prevents excessive inrush current during start-up. The shutdown feature reduces quiescent current to less than 1.0 μA.

The SKY81290 is available in a 14-pin, 3 x 3 mm TDFN package and a 14-pin, 3 x 2 mm TDFN package.


Flash IOUT Total (mA)1500
Movie Mode IOUT Total (mA)143
LED Channels1
Min. VIN (V)2.7
Max. VIN (V)5.5
Max. VOUT (V)5.5
Max. Shutdown Current (μA)1
Typ. IQ (μA)230
Peak Efficiency88%
PackageTDFN, 14L
Package (mm)3 x 3 x 0.75 / 3 x 2 x 0.75


  • Input voltage range: 2.7 V to 5.5 V
  • Single channel flash output
  • Up to 1.2 A regulated output current
  • Up to 88% efficiency
  • Switching frequency: 2.0 MHz
  • Separate flash enable
  • Single resistor sets Flash and Movie Mode current
  • Flash safety timer
  • AS2Cwire single wire programming:
    • Movie Mode current
    • Flash/Movie Mode current ratio
    • Maximum flash current ratio
  • True Load Disconnect
  • Soft start and input current limit
  • Over voltage (open LED, open circuit), short circuit, and over-temperature protection
  • TDFN (14-pin, 3 x 3 mm and 3 x 2 mm) packages (MSL1, 260 °C per JEDEC J-STD-020)

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