UTC 3563

      The UTC 3563 is a monolithic control circuit containing the primary functions required for DC to DC converters and highside-sensed constant current source. The device consists of an internal temperature compensated reference, comparator, controlled duty cycle oscillator with an active current sense circuit,bootstrapped driver, and high current output switch.This device is specifically designed to construct a constant current source for battery chargers with a minimum number of external components.What's more,it is used as a saver for cellular phones and step-Down DC-DC converter module. 
      Here you can get some information about the features of UTC 3563 .There are nine features as follows.First,it has 3V to 30V input voltage operation. Secondly,it contains internal 2A peak current switch.Thirdly,it can deliver 1.5A continuous current without requiring a heat sink.Fourthly,it has a bootstrapped driver which can drive the NPN output switch to saturation for higher efficiency and less heat dissipation.Fifthly,it has high side current sense capability.Sixthly,it has high efficiency (up to 90%).Seventhly.it has internal ±2% reference.Eighthly,it has low quiescent current at 1.6mA.At last,the frequency operation from 100Hz to 100KHz.
      You have to understand the absolute maximum ratings of UTC 3563 (Ta=25).The supply voltage (VCC) is 30 V.The comparator input voltage range (Vi) is from -0.3 to +30 V.The switch collector voltage (V_C(switch)) is 30 V.The switch emitter voltage (V_E(switch)) is 30 V.The switch collector to emitter voltage (V_CE(switch)) is 30 V.The driver collector voltage (V_C(driver)) is 30 V.The switch current (I_SW) is 2 A.The operating junction temperature (Tj) is 125 .The operating ambient temperature range (Ta) is from 0 to +70 .The storage temperature range (Tstg) is from -65 to +150 .