Allegro MicroSystems ARG81800 40V Synchronous Buck Regulators

Allegro MicroSystems ARG81800 40V Synchronous Buck Regulators implement all the control and protection circuitry to produce a PWM regulator with ±1.5% output voltage accuracy. The ARG81800 offers ultralow quiescent current to enable “keepalive” supply operation with minimal current draw from the supply during very light load regulation.

Two versions of the ARG81800 are available, 500mA and 1A, so the physical size of the power components can be optimized for lower current systems, thus reducing PCB area and saving cost. PWM switching frequency is programmed over a wide range to balance efficiency, component sizing, and EMC performance. If VIN decays and the duty cycle reaches its maximum, the ARG81800 will automatically fold back its PWM frequency to extend the duty cycle and maintain V_OUT.

The ARG81800 is Automotive AEC-Q100 qualified and housed in a low profile 20-pin wettable flank QFN package (suffix “ES”) with an exposed power pad.

Features

Automotive AEC-Q100 qualified
Input operating voltage range of 3.5V to 36V
- Withstands surge voltages to 40V for load dump
Low-Power (LP) mode- draws just 8μA from VIN while maintaining 3.3VOUT or 5.0VOUT
AUTO mode allows automatic transition between PWM and LP mode based on load current
Programmable PWM frequency (fSW) of 250kHz to 2.4MHz
PWM frequency dithering and controlled switch node slew rate reduce EMI/EMC signature
CLKOUT allows the interleaving and dithering of “downstream” regulators using their synchronization inputs
Interleaving minimizes input filter capacitor requirement and improves EMI/EMC performance
Synchronization of PWM frequency to an external clock on SYNCIN pin

Adjustable output voltage of ±1.5% accuracy over operating temperature range (-40°C to 150°C)
Maximized duty cycle at low VIN improves dropout
Soft recovery from dropout condition
Adjustable soft-start time controls inrush current to accommodate a wide range of output capacitances
External compensation provides flexibility to tune the system for maximum stability or fast transient response
Enable input can command ultralow 1μA shutdown current
Open-drain PGOOD output with rising delay
Pre-bias startup allows quick restart and avoids reset
Overvoltage, pulse-by-pulse current limit, hiccup mode short circuit, and thermal protection
Robust FMEA: pin open/short and component faults

Applications

Infotainment
Navigation systems
Instrument clusters
Audio systems
ADAS Applications

Battery-powered systems
Industrial systems
Network and telecom
Home audio
HVAC Systems

Allegro MicroSystems ARG81800 40V Synchronous Buck Regulators

Features

Applications

Typical Application Diagram

Block Diagram

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