MAX8989具有线性旁路模式的多模式PA供电降压转换器

MAX8989具有线性旁路模式的多模式PA供电降压转换器
MAX8989概述
The MAX8989 step-down converter is optimized for powering the power amplifier (PA) in multistandard handsets such as LTE, WCDMA, GSM, and EDGE. The device integrates a high-efficiency PWM step-down converter for medium- and low-power transmission with an 85mΩ (typ) low dropout (LDO) bypass regulator, in parallel with the step-down converter, enabling high-power transmission.
The IC uses an analog input driven by an external DAC to control the output voltage linearly for continuous PA power adjustment. The bypass LDO powers the PA directly from the battery during high-power transmission or in case of insufficient headroom between the input and programmed output. The bypass LDO is enabled when the output voltage is greater than 1.0V. In the case where the output current exceeds the step-down converter current limit, the bypass LDO provides supplementary current to the output, ensuring a stable output voltage. The bypass LDO also provides a smooth transition between step-down regulation and operation in dropout.
The IC is available in a 9-bump, 1.6mm x 1.6mm WLP package (0.69mm max height).
MAX8989关键特性
PA Step-Down Converter
25µs (typ) Settling Time for 0.4V to 3.2V Output Voltage Change
Dynamic Output Voltage Setting from 0.4V to VIN
85mΩ pFET and 100% Duty Cycle for Low Dropout
2MHz Switching Frequency
Low Output Voltage Ripple
2% Output Voltage Accuracy Over Load, Line, and Temperature
Tiny External Components
2.5A Output Current Capability
Simple Logic On/Off Control
Low 0.1µA Shutdown Current
2.7V to 5.5V Supply Voltage Range
Thermal Overload Protection
1.6mm x 1.6mm WLP Package (0.69mm max Height)
MAX8989应用/使用
LTE、WCDMA、GSM和EDGE手机/智能电话