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20A Smart Power Stage with Current and Temperature Monitoring

MaxLinear, Inc. launched the company’s first Smart Power Stage (SPS). The fully optimized XR78021 integrates HS/LS MOSFETs that support up to 20A output current. The power stage comes in a compact 4mm x 5mm QFN package. MaxLinear optimized the package design to provide very low thermal impedance and excellent EMI performance by minimizing parasitic inductances.

The XR78021 targets power conversions from 12V down to as low as 0.6V to meet the requirements of processors and chipsets in servers, networking, and telecommunications equipment.

The XR78021 combines temperature monitoring and a current sense amplifier with temperature compensation supporting DCR current sensing. The temperature and current telemetry features enable reliable and robust solutions for mission-critical end equipment.

Also known as “DrMOS” (Driver plus MOSFETs), the package design has very low thermal impedance and provides excellent EMI performance by minimizing parasitic inductances. The ratio of the MOSFET RDS(on) is optimized for conversions from 12V rails to the low output voltages needed for the latest processor and chipsets of computing systems.

The company notes that computing systems are demanding more and more telemetry of the power system. The XR78021 monitors internal temperature (TOUT pin) and uses that temperature information to provide a temperature-corrected current output (IOUT pin) derived from the inductor DCR.

The output current information has minimal phase delay and is suitable for use with current-mode PWM and valley-current-mode constant on-time control. As a secondary function, TOUT serves as a fault flag for VCC UVLO and Over-Temp fault. The XR78021 is offered in a 4x5x0.9mm QFN package.

“The XR78021 expands our ability to meet the needs of server and enterprise markets,” said Joseph Tseng, MaxLinear Director of Marketing, Power Management. “The XR78021 can be used on the +1 phase in multiphase controllers to power 12A to 20A rails and provides real-time temperature monitoring and reporting on critical CPU, memory and system power rails.”

“In addition to MaxLinear’s success of 15A and 20A constant on-time regulators in the server market, the XR78021 gives customers the option to have telemetry of current and temperature. When using the XR78021’s smaller form factor 4mm x 5mm package instead of the standard 5mm x 6mm footprint in systems, customers can realize much-needed space savings,” Joseph Tseng said.

Features
  • 20A Integrated Power Stage
  • Input Voltage Range: 4.5V to 17V
  • Output Voltage Range: 0.6V to 3.3V
  • 0.6V to 5.5V without current sense
  • IMON output 5mV/A (DCR=0.29mΩ) with temperature compensation
  • Suitable for current mode control loops
  • TOUT output 8mV/°C with fault flags for VCC UVLO and temperature
  • Designed for 3.3V tristate PWM outputs
  • Boost pin refresh
  • 4mm x 5mm x 0.9mm RoHS-compliant package