LD7550

The LD7550 is designed as a low cost, low startup current, current mode PWM controller with green-mode power-saving operation. The integrated functions such as the leading-edge blanking of the current sensing, internal slope compensation and the small SOT-26 package provide the users a high efficiency, low external component counts, and low cost solution for AC/DC power applications.

LD7550 has ten features. (1)High voltage CMOS process with excellent ESD protection. (2)Very low startup current (typical 5uA). (3)Under voltage lockout (UVLO). (4)Current mode control with cycle-by-cycle peak current limiting. (5)Leading edge blanking on CS pin. (6)Programmable switching frequency. (7)Internal slope compensation. (8)Proprietary green-mode control for power saving. (9)Non-audio-noise green mode control. (10)300mA driving capability. Those are all the main features.

Some absolute maximum ratings of LD7550 have been concluded into several points as follow. (1)Its supply voltage Vcc would be 36V. (2)Its CMOP, RT, CS would be from -0.3V to 7V. (3)Its operating junction temperature would be 150°C. (4)Its package thermal resistance DIP-8 would be 100°C/W. (5)Its package thermal resistance SOT-26 would be 250°C/W. (6)Its lead temperature DIP-8 soldering 10 seconds would be 260°C. (7)Its lead temperature SOT-26 soldering 10 seconds would be 260°C. It should be noted that stresses above those listed in absolute maximum ratings may cause permanent damage to device.

Also some electrical characteristics of LD7550 are concluded as follow. (1)Its startup current would be typ 5uA and max 25uA. (2)Its operating current would be typ 3mA and max 4mA at Vcomp=0V and would be typ 2mA at Vcomp=3V and would be typ 0.7mA at Vcomp=open. (3)Its UVLO off would be min 10.4V and typ 11.4V and max 12.4V. (4)Its UVLO on would be min 14.8V and typ 16V and max 17.5V. And so on. If you have any question or suggestion or want to know more information please contact us for details. Thank you!