Description

The MAX8544EEP+ is a DC DC switching controller that belongs to the MAX850 series of low-noise, inverting, charge pump power supplies. This model is specifically designed for cellular phone transmitter amplifiers where biasing GaAsFETs is required. The MAX8544EEP+ offers fixed -4.1V or adjustable -0.5V to -9V output at 5mA. It has an input voltage range of 4.5V to 10V. An internal linear regulator reduces the output voltage ripple to 2mVp-p. With a well-filtered control voltage (VCTRL), the MAX8544EEP+ achieves typical output ripple of less than 1mVp-p. The model has a low cost 8-Pin SO package.

Specifications and features

• Fixed -4.1V or adjustable -0.5V to -9V output at 5mA
• 4.5V to 10V input voltage range
• 2mVp-p output voltage ripple (MAX850–MAX852)
• 1mVp-p output voltage ripple (MAX853)
• 100kHz charge-pump switching frequency (MAX850/MAX851/MAX853)
• External synchronizing clock input (MAX852)
• Logic-level shutdown mode: 1µA max over temperature (MAX850/MAX852/MAX853)

Application Scenarios

The MAX8544EEP+ is suitable for the following applications:

• Cellular phones
• Negative regulated power supplies
• Personal communicators, PDAs
• Wireless data loggers
• Continuously adjustable GaAsFET bias
• LCD-bias contrast control

Comparison

• The MAX8544EEP+ provides fixed and adjustable output voltages depending on the requirements of the application
• Low cost 8-Pin SO package

• The input voltage range of 4.5V to 10V may not be suitable for all applications
• The output current limit of 5mA may not be sufficient for some applications