LT3485-0

The LT3485 family of photoflash chargers are highly integrated ICs containing complete charger and IGBT drive functions. The patented control technique of the LT3485-x allows it to use extremely small transformers. Output voltage detection requires no external circuitry. The turns ratio of the transformer controls the final charge voltage. While charging,the output voltage on the capacitor may be monitored by a microcontroller from the monitor pin. Each device contains an on-chip high voltage NPN power switch, which can withstand negative voltages on the switch pin without an external Schottky diode. The device features a VBAT pin, which allows the use of two AA cells to charge the capacitor. The internal circuitry operates from the VIN pin. The LT3485-0 has a primary current limit of 1.4A, whereas the LT3485-3, LT3485-2,and LT3485-1 have current limits of 2A, 1A and 0.7A respectively.These different current limits result in tightly controlled input currents.The CHARGE pin gives full control of the part to the user.Driving CHARGE low puts the part in shutdown. The DONE pin indicates when the part has completed charging. The LT3485 series of parts are housed in a leadless (3mm * 3mm) DFN package.

The LT3485 family has some absolute maximum ratings.The VIN voltage is 10V.The VBAT voltage is 10V.The SW voltage is -1V to 50V.The SW Pin negative current is -0.5V.The charge voltage is 10V.The igbtin voltage is 10V.The igbtout voltage is 10V.The done voltage is 10V.The igbtpwr voltage is 10V.The VMONT voltage is 10V.The current into done pin is 0.2mA/1mA.The maximum junction temperature is 125.The operating temperature range is -40 to 85.The storage temperature range is 65 to 125.