Quad Output Mini PMIC for Automotive Camera Applications

说明

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The MAX25249/MAX25249B are high-efficiency, four-output PMICs that integrate three DC-DC converters and a high-PSRR LDO, with OV/UV monitoring on all outputs. OUT1 is a 1A high-voltage synchronous step-down converter operating from power over coax or car battery. OUT2 and OUT3 low-voltage synchronous step-down converters operate from OUT1 and provide a 0.8V to 3.9875V output voltage range. OUT2 can deliver 1.2A for high-megapixel cameras and high-speed serializers. OUT3 delivers 0.5A to power the secondary rails of the imager, serializer, and MCU. OUT4 is a low-voltage, low-noise, high-PSRR LDO for imager power. All buck converters achieve ±1.5% output voltage accuracy over load, line, and temperature range. Overvoltage and undervoltage faults are monitored with ±1.3% accuracy around the set voltage, and errors are communicated through active-low RESET.

The devices feature a 2.2MHz fixed-frequency PWM mode for better noise immunity and load-transient response. The high-frequency operation allows for the use of all ceramic capacitors and minimizes external components. The programmable spread-spectrum frequency modulation minimizes radiated electromagnetic emissions. Integrated low-R_DS(ON) switches improve efficiency at heavy loads and make layout simpler than discrete solutions.

Sequencing through the use of EN23 and EN4 pins and factory-settable output voltages increase flexibility for different image sensors and configurations. Other features include soft-start, overcurrent, and overtemperature protections. The MAX25249/MAX25249B are compliant to ASIL-B ratings and are specified for operation over the -40°C to +125°C automotive temperature range.

关键特性

• Multiple Functions for Small Size
  • 1A Synchronous High-Voltage Buck Converter
    • Input Voltage Range 4.5V to 36V
    • 3V to 4V Output Voltage in 50mV steps
  • Two Synchronous Low-Voltage Buck Converters
    • OUT2 and OUT3 Provide up to 1.2A
    • 0.8V to 3.9875V in 12.5mV steps
  • LDO for Camera Sensor; 50dB at 1kHz.
  • 2.2MHz Operation
  • Active-Low RESET Output – Push-Pull or Open-Drain
• High-Precision
  • ±1.5% Output Voltage Accuracy
  • ±1.3% OV/UV Monitoring Accuracy
• Diagnostics and Features
  • ASIL-B Compliant
  • Redundant Reference
• Robust for the Automotive Environment
  • Current-Mode, Forced-PWM Operation
  • Overtemperature and Short-Circuit Protection
  • 3.5mm x 3.5mm 20-Pin TQFN
  • -40°C to +125°C Grade 1 Automotive Temperature Range
  • AEC-Q100 Qualified

应用

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