Automotive Electronics

3.2MHz, 500mA Dual Step-Down Converters for Automotive Cameras

The MAX20019 and MAX20020 from Maxim Integrated Products are 2.2MHz and 3.2MHz dual step-down converters with integrated high-side and low-side MOSFETs. The high-voltage step-down converter is designed for continuous operation up to 17V input voltages.

The output voltage is factory preset. Buck 1 is preset to 3.3V, 3.0V, or 2.8V. Buck 2 is preset to 1.8V, 1.5V, 1.2V, or 1V. Another option is Buck 1 preset to 5V and Buck 2 preset to 3.3V. Applications are expected to include automotive point-of-load power and surround-view camera power supplies.

The low-voltage buck features fixed-frequency pwm-mode operation with a switching frequency of 2.2MHz or 3.2MHz. High-frequency operation allows for an all-ceramic capacitor design and small-size external components. The low-resistance on-chip switches ensure high efficiency while minimizing critical inductance.

A 500mV enable hysteresis on the MAX20019 allows the use of long, low-cost coax cables, even during slow startup situations. The MAX20020’s Buck 1 starts after VSUP is greater than 5.5V and Buck 1 is driven by the EN input.

Protection features include overvoltage (OV) protection, cycle-by-cycle current limit, and thermal shutdown with automatic recovery. The buck converters operate 180° out-of-phase from each other to minimize input-current ripple.

MAX20019, MAX20020 functional block diagram (click on image to enlarge)

Key features include:

  • Small Solution Size
    • 2mm x 3mm x 0.75mm 10-pin TDFN with an Exposed Pad
    • 2MHz and 3.2MHz Operation Allows Smaller System Size
    • No External Components Needed for Soft-Start
  • Cable Flexibility
    • 500mV Enable Hysteresis Allows for Long, Low-Cost Cables During Slow Starts
  • EMI Solutions
    • Optional Spread-Spectrum Frequency Modulation
    • Pinout Placement Allows for Tight PCB Layout of Switching Nodes
  • Self-Protected
    • Overvoltage Protection, Thermal Shutdown, Short-Circuit Protection
  • Automotive Ready
    • Wide 3.5V to 17V Input Voltage Range for Power-Over-Coax
    • Automotive Temperature Range -40°C to +125°C
    • AEC-Q100 Qualified

The MAX20019/MAX20020 evaluation kits (EV kits) are fully assembled and tested PCBs that demonstrate the MAX20019 and MAX20020 dual step-down converters with integrated high-side and low-side MOSFETs.

The EV kits provide a high-efficiency power-conversion solution and generate low output voltage from the dual step-down converters: OUT1 steps down up to 16V high input to 3.3V to provide the power to OUT2, while OUT2 steps down the OUT1 voltage to 1.8V. The 3.2MHz switching-frequency operation allows for the use of all ceramic capacitors and minimizes external components. The EV kits feature on/off jumper controls to enable/disable OUT1 and OUT2.