HT7936B

HT7936A/HT7936B White LED Step-up Charge Pump Converter Features · Input voltage range: 2.8V to VOUT · Driving current: 110mA (HT7936A), · Oscillator frequency: 1MHz · Soft start function, current limit, 150mA (HT7936B) · Fixed output voltage: 5V (HT7936A), short circuit protection · Small outline SOT23-6 package 4.5V (HT7936B) Applications · Cellular phones · PDAs · DSCs · Handheld devices · White LED display backlighting General Description The HT7936A and HT7936B are charge-pump type DC-DC step-up converter devices, which can generate regulated fixed output voltages of 5.0V and 4.5V. Their high degree of functional integration requires only the addition of three external capacitors, namely a flying capacitor and an input and output capacitor, to implement a full step-up conversion function. The devices have the additional benefit of an integrated soft start function to reduce the level of in-rush current during device power on. The operating voltage range is from 2.8V to the full output voltage value, VOUT. To meet the demands of today¢s power sensitive applications, the devices, have a very low standby current value as well as the extra safety features of current limit and short circuit protection. This range of device features, supplied in 6-pin SOT-23-6 package type, will ensure that these device will find excellent use in a wide range of DC-DC step-up converter applications. Selection Table Part No. HT7936A HT7936B Output Voltage 5.0V 4.5V Tolerance ±4% ±4% Packa...