MAXREFDES1142: Ultra miniature Two Layer 4A, 1.8V Step-Down DC-DC Converter with Integrated Switches Using MAX15051


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The MAX15051 is a high-efficiency switching regulator that delivers up to 4A load current at output voltages from 0.6V to (0.9 x VIN). The device operates from 2.9V to 5.5V, making it ideal for on-board point-of-load and postregulation applications. The total output-voltage accuracy is within ±1% over load, line, and temperature.

The MAX15051 features 1MHz fixed-frequency PWM operation, and pulse-skip mode to improve light-load efficiency. The high operating frequency allows for small-size external components. The low-resistance on-chip nMOS switches ensure high efficiency at heavy loads while minimizing critical parasitic inductances, making the layout a much simpler task with respect to discrete solutions.

The device incorporates a high-bandwidth (> 26MHz) voltage-error amplifier. The voltage-mode control architecture and the voltage-error amplifier permit a Type III compensation scheme to achieve maximum loop bandwidth, up to 200kHz. High loop bandwidth provides fast transient response, resulting in less required output capacitance and allowing for all-ceramic capacitor designs.

The output overload hiccup protection and peak current limit on both high-side and low-side MOSFETs provide for ultra-safe operation in the cases of short-circuit conditions, severe overloads, or in converters with bulk electrolytic capacitors.

The output voltage is adjustable by using two external resistors at the feedback or by applying an external reference voltage to the REFIN/SS input.

The MAX15051 offers a programmable soft-start time using one capacitor to reduce input inrush current. A built-in thermal shutdown protection ensures safe operation under all conditions. Other features include the following:


  • 20μA Startup Current in UVLO
  • Programmable Input Undervoltage Lockout
  • Programmable Input Overvoltage Protection
  • Switching Frequency Synchronization
  • Adjustable Soft-Start
  • Programmable Slope Compensation
  • Fast Cycle-by-Cycle Peak Current Limit
  • 70ns Internal Leading-Edge Current-Sense Blanking
  • Hiccup Mode Output Short-Circuit Protection


Designed, Built, Tested

Board pictured here has been fully assembled and tested. Not available for sale.



Input Type Vin(Min) Vin(Max) Iout(Max) Single/Multiple Output Vout(V) Pout(W) Isolated/Non-Isolated Topology
DC 3 3.6 4 - 1.8 7.2 Non-Isolated Synchronous Buck


Input Type DC
Vin(Min) 3
Vin(Max) 3.6
Iout(Max) 4
Single/Multiple Output -
Vout(V) 1.8
Pout(W) 7.2
Isolated/Non-Isolated Non-Isolated
Topology Synchronous Buck

Maxim Devices (1)

Part Number Name Product Family Order Design kits and evaluation modules
MAX15051 High-Efficiency, 4A, 1MHz, Step-Down Regulators with Integrated Switches in 2mm x 2mm Package Switching Regulator - Switching Regulators Buy Now Design Kits

Maxim Devices (1)

Part Number Product Family
Switching Regulator - Switching Regulators
High-Efficiency, 4A, 1MHz, Step-Down Regulators with Integrated Switches in 2mm x 2mm Package

Design Files (6)

Date Type


(ZIP, 3MB)



(PDF, 1MB)


MAXREFDES1142 Test Results

(PDF, 141KB)


MAXREFDES1142 - Ultraminiature Two Layer 4A, 1.8V Step-Down DC-DC Converter with Integrated Switches Using MAX15051

(PDF, 631KB)



(PDF, 24KB)



(PDF, 95KB)

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