Analogic AAT2782三输出电源方案

Analogic 公司的AAT2782是三路输出的PMIC:两路降压稳压器和一路低输入电压低压降(LDO)稳压器.降压稳压器的输入电压从2.7V到5.5V,可提供1200mA和600mA的输出电流,而LDO稳压器的输入电压从1.5V到5.5V,并提供高效率低噪音的输出.另外,LDO的输入可连接到降压稳压器的输出1或2.降压稳压器的效率可高达97%,而LDO稳压器的效率可高达80%. AAT2782可广泛应用在手机和智能手机,微处理器/DSP内核电源,PDA,PMP以及无线数据系统.本文介绍了AAT2782的主要特性,方框图以及AAT2782的应用电路图.

AAT2782 | Triple Output PMIC: Dual Buck with Low-VIN LDO
The AAT2782 provides three independently regulated DC outputs: two step-down (Buck) regulators and a single low input voltage, low drop-out (LDO) regulator. The input voltage range for the step-down regulators is 2.7V to 5.5V, while the LDO regulator allows inputs from 1.5V to 5.5V. The low input voltage LDO regulator allows high efficiency, step-down, low noise outputs. In addition, the LDO input may be connected to step-down outputs 1 or 2.

The Channel 1 and 2 step-down regulators can deliver up to 1200mA and 600mA output current, respectively. Step-down output voltages are set with external resistors. Switching frequency is set at 1.3MHz to ensure small external filtering components. Current mode control assures fast transient response and stable operation across the operating range. The Channel 3 LDO regulator can deliver up to 400mA with -80dB power supply rejection ratio (PSRR) and 65μVRMS output noise with an optional bypass capacitor. The LDO output voltage is factory set with a default voltage of 1.20V. Independent enable and input pins are provided. The device consumes low quiescent current and provides high efficiency across the load range for maximum life in battery systems. The AAT2782 is available in the Pb-free, 16-pin TDFN34 package and is rated over the -40°C to 85°C operating temperature range.

AAT2782主要特性:
VIN Range Step-Down (Buck): 2.7V to 5.5V
VIN Range Low Drop-Out (LDO): 1.5V to 5.5V
Output Voltage Range: 0.6V to VIN
Step-Down Output Current:
Channel 1: 1200mA
Channel 2: 600mA
LDO Output Current:
Channel 3: 400mA
High Efficiency with Low RDS(ON) Switches
Step-Down up to 97%
LDO Regulator up to 80%
Total Quiescient Current 170μA
Shutdown Current: 1μA
Step-Down Converters
1.3MHz Switching Frequency
Current Mode Control
Cycle-by-Cycle Current Limit
High Efficiency Light-Load Mode Operation
LDO Converter
Ultra Low Noise with Bypass Capacitor
Over-Current Protection
200μs Internal Soft Start
Over-Temperature Protection
TDFN34-16 Low Profile Package
-40°C to 85°C Temperature Range

AAT2782应用:
Cellular and SmartPhones
Microprocessor / DSP Core / IO Power
PDAs and Handheld Computers
Portable Media Players
Wireless Data Systems



图1. AAT2782方框图
典型应用电路




图2. AAT2782典型应用电路



图3. AAT2782应用电路图