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Multimode PA Step-Down Converter with Linear Bypass Mode

Compact Package (1.6mm x 1.6mm) Powers Multimode PAs Efficiently to Extend Talk Time Up to 25% in Mobile Phones

Product Details

Key Features

Simplified Block Diagram

Technical Docs

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Key Features

  • 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)

Applications/Uses

  • LTE, WCDMA, GSM, and EDGE Cell Phones/Smartphones

Description

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).

Simplified Block Diagram

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .

Sampling:
Selecting the Sample button above will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.