HT7936B Datasheet | Holtek Semiconductor

Features - Input voltage range: 2.8V to VOUT - Driving current: 110m A (HT7936A), - Oscillator frequency: 1MHz - Soft start function, current limit, 150m A (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% Package SOT23-6 SOT23-6 .. Rev 1.00 December 28, 2009 HT7936A/HT7936B Block Diagram C + V IN C - M 4 M 1 M 2 M 3 S h o r t C ir c u it P r o te c io n C o n tro l G N D V R E F 1 M H z O S C N o te : D u r in g o p e r a tio n th e fo llo w in g s e q u e n c e o c c u r s : 1 . M 1 , M 3 O n / M 2 , M 4 O ff 2 . M 2 , M 4 O n / M 1 , M 3 O ff Pin Assignment C + 6 V IN 5 C 4 T o p V ie...