The MAX8643 high-efficiency switching regulator delivers up to 3A load current at output voltages from 0.6V to (0.9 × VIN).The IC operates from 2.35V to 3.6V, making it ideal for on-board point-of-load and postregulation applications. Total output error is less than ±1% over load, line, and temperature.
The MAX8643 features fixed-frequency PWM mode operation with a switching frequency range of 500kHz to 2MHz set by an external resistor. High-frequency
operation allows for an all-ceramic capacitor design. The high operating frequency also allows for small-size external components.
The low-resistance on-chip nMOS switches ensure high efficiency at heavy loads while minimizing critical inductances, making the layout a much simpler task with respect to discrete solutions. Following a simple layout and footprint ensures first-pass success in new designs.
The MAX8643 comes with a high-bandwidth (> 14MHz) voltage-error amplifier. The voltage-mode control architecture and the voltage-error amplifier permit a type III compensation scheme to be utilized to achieve maximum loop bandwidth, up to 20% of the switching frequency. High loop bandwidth provides fast transient
response, resulting in less required output capacitance and allowing for all-ceramic capacitor designs.
The MAX8643 provides two tri-state logic inputs to select one of nine preset output voltages. The preset output voltages allow customers to achieve ±1% output-voltage accuracy without using expensive 0.1% resistors. In addition, the output voltage can be set to any customer value by either using two external resistors at the feedback with 0.6V internal reference or
applying an external reference voltage to the REFIN input. The MAX8643 offers programmable soft-start time using one capacitor to reduce input inrush current.
The MAX8643 is available in a lead-free, 24-pin, 4mm x 4mm thin QFN package.
For assistance with selecting appropriate capacitors, resistors, and inductors, try our online component selection spreadsheet.
Key Features
Applications/Uses
Internal 37mΩ RDS(ON) MOSFETs
Continuous 3A Output Current
±1% Output Accuracy Over Load, Line, and Temperature
Operates from 2.35V to 3.6V Supply
Adjustable Output from 0.6V to (0.9 × VIN)
Soft-Start Reduces Inrush Supply Current
500kHz to 2MHz Adjustable Switching Frequency
Compatible with Ceramic, Polymer, and Electrolytic Output Capacitors
VID-Selectable Output Voltages
0.6, 0.7, 0.8, 1.0, 1.2, 1.5, 1.8, 2.0, and 2.5V
Fully Protected Against Overcurrent and Overtemperature
Notes: **This pricing is BUDGETARY, for comparing similar parts. Prices are in
U.S. dollars and subject to change. Quantity pricing may vary
substantially and international prices may differ due to local
duties, taxes, fees, and exchange rates. For volume-specific prices
and delivery, please see the price and availability page
or contact an authorized distributor.
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