LP3927 Datasheet | National Semiconductor

Description The LP3927 system power management IC is designed for cellular/PCS handsets as well as other portable systems that require intelligent power management. Each device contains five low-dropout linear regulators (LDO’s), a reset timer, a power-up control logic, a general-purpose open drain output that can be used to light LEDs, and a CMOS rail-to-rail input/output operational amplifier. Each linear regulator features an extremely low dropout voltage of 100 m V (typ) at maximum output current. LDO1 and LDO2 are powered on and off by either the KYBD or the VEXT pin. LDO3, LDO4 and LDO5 each have its independent enable pin. LDO1 and LDO4 are rated at 150 m A each, LDO2 and LDO5 are rated at 200 m A each and LDO3 is rated at 100 m A. All LDO’s are optimized for low noise and high isolation. The open drain output current sink can be programmed up to 150 m A by using an external low cost resistor. A single supply, low voltage operational amplifier has rail to rail input and output with 600 k Hz of gain-bandwidth product. Key Specifications 3.0V to 5.5V Input Voltage Range Two 200 m A, Two 150 m A and One 100 m A LDO’s 100 m V typ Dropout Voltage @ IMAX 150 m A General-Purpose Open-drain programmable current sink for back light LED n Low Voltage Rail to Rail Input/Output Operational Amplifier n 28 pin LLP package n n n n Applications n n n n Cellular/PCS handsets PDA’s, Palmtops, and portable terminals Single- Cell Li+ Systems 2- or 3- Cell Ni MH, Ni Cd or Alkaline System Typical Application Circuit VDD1, VDD2 and VDD3 must be tied together externally. Collectively called VDD. © 2002 National Semiconductor Corporation DS200379 .national. LP3927 Pin Out Diagram (Top View) Output Current Rating and Voltage Options IMAX (m A) LDO1 LDO2 LDO3 LDO4 LDO5 150 200 100 150 200 Voltage Options (V) 1.8, 1.9, 2.5, 2.6- , 2.7 1.8, 2.85- , 2.9, 3.0 2.7, 2.8, 2.9- , 3.0 2.7, 2.8, 2.9- , 3.0 2.7, 2.8, 2.9, 3.0- - denotes the voltage options that are available...