4.5V to 60V, 3.5A, High-Efficiency, Synchronous Step-Down DC-DC Converter with Internal Compensation

The MAX17573 is a high-efficiency, high-voltage, synchronous step-down DC-DC converter with integrated MOSFETs that operates over a 4.5V to 60V input. The converter can deliver up to 3.5A current. Output voltage is programmable from 0.9V up to 90% of VIN. The feedback voltage regulation accuracy over -40°C to +125°C is ±0.9%.

The device features a peak-current-mode control architecture. An internal transconductance error amplifier produces an integrated error voltage at an internal node, which sets the duty cycle using a PWM comparator, a high-side current-sense amplifier, and a slope-compensation generator. At each rising edge of the clock, the high-side MOSFET turns on and remains on until either the appropriate or maximum duty cycle is reached or the peak current limit is detected. During the high-side MOSFET’s on-time, the inductor current ramps up. During the second half of the switching cycle, the high-side MOSFET turns off and the low-side MOSFET turns on. The inductor releases the stored energy as its current ramps down and provides current to the output.

The device can operate either in the pulse-width modulation (PWM), pulse-frequency modulation (PFM), or discontinuousconduction mode (DCM) control schemes. A programmable soft-start feature allows users to reduce input inrush current. The device also incorporates an enable/input undervoltage lockout pin (EN/UVLO) that allows the user to turn on the part at the desired input voltage level. An open-drain RESET pin provides a delayed power-good signal to the system upon achieving successful regulation of the output voltage.

APPLICATIONS

* Factory Automation

* Aftermarket Automotive

* General Point of Load

* Reduces External Components and Total Cost

* No Schottky-Synchronous Operation

* Internal Loop Compensation

* All-Ceramic Capacitors, Compact Layout

* Reduces Power Dissipation

* Peak Efficiency of 95.4% at VIN = 12V, VOUT = 5V at 500kHz Switching Frequency * Pin-to-Pin Compatible with MAX17574, and Improved Efficiency through Superior Switching Performance compared to MAX17574 * PFM and DCM Modes Enable Enhanced LightLoad Efficiency * Auxiliary Bootstrap Supply (EXTVCC) for Improved Efficiency * 2.8μA Shutdown Current