FEATURES AND BENEFITS

• AEC-Q100 Grade 0 qualified

• VIN Range: 3.5 to 36 V operating, 40 V transient

• VOUT: 3.3 V, ±1.5% accuracy, ‒40°C to 150°C

(5 V for the A81805-1)

• Up to 2.5 A of continuous output current

• High Efficiency: 92%, 12 V input to 5 V output, 1 A, 2 MHz

• Integrated Compensation: Eliminates three external

components

• Low-Power (LP) mode: 6 µA IQ from VIN at no load,

automatic transition from LP to PWM mode

• Fixed-Frequency PWM (fOSC): 400 kHz to 2.5 MHz

programmable

• Synchronizable Switching Frequency (400 kHz to

2.5 MHz): PLL-based, fSYNC can be above or below fOSC

• Spread spectrum applied: Helps to pass CISPR25 class 5

• Internally set Soft-Start

• Accurate ENABLE input threshold

• Open-drain PGOOD output with delay

• Pre-bias startup capable

• Maximized duty cycle at low VIN improves dropout

• Overvoltage, pulse-by-pulse current limit, hiccup mode

short-circuit, and thermal protections

• Robust FMEA: pin open/short and component faults

APPLICATIONS

• Infotainment

• Battery-powered systems

• Industrial systems

• Container tracking

• Handheld instruments

• Instrument clusters

• Audio systems

• ADAS

DESCRIPTION

The A81805 is a full-featured, 2.5A, low EMI, DC-DC regulator

designed to satisfy demanding power delivery requirements

of automotive and industrial applications. The A81805 and

A81805-1 include all the control and protection circuitry to

produce a robust 3.3 V or 5 V DC output voltage respectively,

with ±1.5% output voltage accuracy over the full operating

temperature range.

Fixed-frequency peak current-mode control is employed to ensure

rapid response to load and line transients with programmable

switching frequency from 400 kHz to 2.5 MHz. Connect the

FSET pin to VCC for a 2.2 MHz switching frequency. The

A81805 can also synchronize to an external clock applied to

the SYNC pin ranging from 400 kHz to 2.5 MHz.

Spread spectrum operation (dithering) is applied, offering

lower EMI levels.

Low power (LP) mode maintains the output voltage at no load

or very light load conditions while drawing only micro-amps

from VIN. No-load input current is a mere 6 µA when operating

from a standard 12 V battery. The A81805 automatically

transitions between PWM and LP modes.

Integrated loop compensation components simplify the design

process while providing fast response to load and line transients.

The A81805 has an internally set soft-start and an open-drain

power good output.

The accurate ENABLE input has programmable turn-on and turnoff thresholds and a low shutdown current of 1 µA if driven low.

Extensive protection features include pulse-by-pulse current

limit, hiccup mode short-circuit protection, BOOT open/short

voltage protection, VIN undervoltage lockout, VOUT overvoltage

protection, and thermal shutdown.

The A81805 is supplied in a thermally enhanced, 4 mm × 4 mm

× 0.75 mm 20-pin wettable flank QFN package (suffix “ES”)

with exposed power pad