Wide Input Voltage, 2.4 MHz, 2.5 A Asynchronous Buck Regulator With Low-IQ Standby, Sleep Mode, External Synchronization, and NPOR Output


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Designed to provide the power supply requirements of next generation car audio and infotainment systems, the A8589 provides all the control and protection circuitry to produce a high current regulator with ±1.0% output voltage accuracy. The A8589 employs pulse frequency modulation (PFM) to draw less than 50 μA from 12 VIN while supplying 3.3 V/40 μA. After startup, the A8589 operates down to at least 3.6 VIN (VIN falling).

Features of the A8589 include a PWM/PFMn mode control input to enable PWM (logic high) or PFM (logic low). If the PWM/PFMn input is driven by an external clock signal higher than the base frequency ( fOSC) the PWM frequency synchronizes to the incoming clock frequency. The SLEEPn input pin commands an ultra-low current shutdown mode requiring less than 5 μA for internal circuitry and 10 μA (max) for MOSFET leakage at 16 VIN, 85ºC. The A8589 has external compensation to accommodate a wide range of frequencies and external components, and provides a power-on reset (NPOR) signal validated by the output voltage.

Extensive protection features of the A8589 include pulse-by-pulse current limit, hiccup mode short circuit protection, open/short asynchronous diode protection, BOOT open/short voltage protection, VIN undervoltage lockout, VOUT overvoltage protection and thermal shutdown.

The A8589 is supplied in a low profile 16-pin TSSOP package with exposed power pad (suffix LP). It is lead (Pb) free, with 100% matte-tin leadframe plating.

  • Automotive AEC-Q100 qualified
  • Withstands surge voltages up to 40 V
  • Operates as low as 3.4 VIN (typ) with VIN decreasing
  • Utilizes pulse frequency modulation (PFM) to draw only tens of microamperes from VIN while maintaining keep-alive VOUT
  • PWM/PFMn mode control input pin
  • Delivers up to 2.5 A of output current with integrated 110 mΩ high voltage MOSFET
  • SLEEPn input pin commands ultra-low current shutdown mode
  • Adjustable output voltage with ±1.0% accuracy from 0°C to 85°C, ±1.5% from –40°C to 150°C
  • Programmable switching frequency: 250 kHz to 2.4 MHz
  • Synchronization capability: applying a clock input to the PWM/PFMn input pin will increase the PWM frequency
  • Active low, power-on reset (NPOR) open-drain output
  • Maximized duty cycle for low dropout
  • Pre-bias startup capable, VOUT will not cause a reset
  • External compensation for maximum flexibility
  • Stable with ceramic or electrolytic output capacitors
  • Excellent set of protection features to satisfy the most demanding applications
  • Overvoltage, pulse-by-pulse current limit, hiccup mode short circuit, and thermal protection
  • Robust FMEA, with pin open/short and component faults
  • Thermally enhanced, surface mount package

Typical Applications

Allegro 16-Pin LP package

The A8589 is supplied in a low profile 16-pin TSSOP package with exposed power pad (suffix LP). It is lead (Pb) free, with 100% matte-tin leadframe plating.

LP Package Documentation

Part Number Specifications and Availability