Step-Up Converter for Handheld Applications

The MAX8969 is a simple 1A step-up converter in a small package that operates in any single-cell Li-ion application. This IC provides protection features such as input undervoltage lockout, short circuit, and overtemperature shutdown.

The IC transitions to skip mode seamlessly under lightload conditions to improve efficiency. Under these conditions, switching occurs only as needed, reducing switching frequency and supply current to maintain high efficiency.

For higher efficiency when input voltage is closer to the output voltage, two special modes of operation are available: track and automatic track. These modes allow users to balance quiescent current (IQ) vs. transient response time into boost mode. In both modes, the p-channel MOSFET acts as a current-limited switch such that VOUT follows VIN. However, in track mode, the boost circuits are disabled and the system controls the boost function with the EN, TREN inputs (IQ = 30µA). In automatic track mode (ATM), the boost circuits are enabled and the device automatically transitions into boost mode when VIN falls to 95% of the target VOUT (IQ = 60µA).

The IC is available in a small, 1.25mm × 1.25mm, 9-bump WLP (0.4mm pitch) package.

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Applications

* Cell Phones * eBooks * GPS, PND * Mobile Internet Devices * Smartphones

* Flexible System Integration

* Up to 1A Output Current

* 2.5V to 5.5V Input Voltage Range

* 3.3V to 5.7V Output Voltage Options

* Integrated Protection Increases System Robustness

* Undervoltage Lockout (UVLO)

* Short-Circuit Protection

* Overtemperature Shutdown

* High Efficiency and Low Quiescent Current Extends Battery Life

* Over 90% Efficiency with Internal Synchronous Rectifier

* 60µA IQ in Automatic Track Mode

* 45µA IQ in Step-Up Mode

* 30µA IQ in Track Mode

* 1µA Shutdown Current

* Skip Mode Under Light Load Condition Improves Efficiency

* True Shutdown™ Prevents Current Flow from OUT to LX

* Soft-Start Limits Inrush Current to 480mA

* Small Package and High Frequency Operation Reduce Board Space

* 9-Bump 1.25mm × 1.25mm WLP Package

* 3MHz PWM Switching Frequency

* Small External Components