AS3645A-ZWLT ams

Datasheet AS3645 1000/720mA Ultra Small High efficient single/dual LED Flash Driver with Safety Features 1 General Description 2 Key Features High efficiency 2MHz fixed frequency DCDC Boost The AS3645 is an inductive high efficient DCDC step up converter with soft start allows small coils converter with two current sources. The DCDC step up converter operates at a fixed frequency of 2MHz and - Stable even in coil current limit includes soft startup to allow easy integration into noise High Flash LED(s) current (720mA for single flash sensitive RF systems. The two current sources (one for LED, 1000mA (2x500mA) for dual flash LED) driving one or two flash LEDs and one for the indicator Separate Indicator LED output LED) can operate in flash / torch / assist (=video) light / indicator modes. If a two flash LEDs configuration is Flash LED(s) cathode connected to ground: used, the LEDs are connected in series. Therefore iden- Improved thermal performance (ground = heat sink) tical current is guaranteed. Simplified PCB layout The AS3645 includes flash timeout, overvoltage, over- Flash, Torch, Assist and Indicator Mode temperature, undervoltage and LED short circuit protec- Protection functions: tion functions. Automatic Flash Timeout timer to protect the LED(s) The AS3645 can be controlled either with parallel inter- Overvoltage and undervoltage Protection face mode to allow simple integration. Alternatively it Overtemperature Protection 2 can be controlled by I C mode to allow a more sophisti- LED(s) short circuit protection cated control of all settings like currents and timings. Dual Interface selectable by pin (parallel interface The interface is selected by a dedicated pin (I2C/EN). 2 mode and I C mode) Available in tiny WL-CSP Packages The AS3645 is available in a space-saving WL-CSP 3x4 balls 0.5mm pitch, 2x1.6mm package size package measuring only 2x1.6mm and operates over the -30C to +85C temperature range. 3 Applications Flash/Torch for mobile phones, digital cameras and PDA Figure 1. Typical Operating Circuit 4 5 / 65 0 0 65 1 0 % 2 % % * % AS3645 1 0 3 23 ,- . ,- ( % % % * % + % www.austriamicrosystems.com (ptr) Revision 1.6 1 - 33 1000/720mA Version Downloaded from Downloaded from DatasheetLib.comDatasheetLib.com - datasheet search engine - datasheet search engine & ()AS3645 Datasheet - Pinout 4 Pinout Pin Assignment Figure 2. Pin Assignments (Top View) AS3645 Pin Description Table 1. Pin Description for AS3645 Pin Number Pin Name Description Power ground - connect to ground (GND) A1 PGND Signal ground - connect to ground (GND) A2 SGND Positive supply voltage input - connect to supply and make a short connection A3 VIN to input capacitor CVIN and to coil LDCDC DCDC converter switching node - make a short connection to the coil LDCDC B1 SW Torch control digital input with pulldown - enables torch function B2 TORCH Indicator LED current source output B3 IND OUT DCDC converter output capacitor - make a short connection to CVOUT C1 VOUT 2 1 I C mode: Digital input with pulldown to control strobe time for flash function C2 STROBE parallel interface mode: Open drain output to identify single/dual flash LED Control pin for the operating mode of the AS3645: 2 1. set to high (e.g. VIN) for I C mode C3 I2C/EN 2. set to low (GND) for parallel interface mode with fixed output currents 3. connect a current set resistor to GND (RISET) for parallel interface mode with adjustable output currents D1 LED OUT Flash LED current source output 2 serial data input/output for I C mode (needs external pullup resistor) D2 SDA/EN2 EN2 input with pulldown for parallel interface mode 2 serial clock input in I C mode D3 SCL/EN1 EN1 input with pulldown in parallel interface mode 1. Application Note: The pin STROBE is usually connected to the camera processor. www.austriamicrosystems.com Revision 1.6 2 - 33 Downloaded from Downloaded from DatasheetLib.comDatasheetLib.com - datasheet search engine - datasheet search engine