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High-Voltage, Step-Down Controller with Synchronous Rectifier for CPU Power

Product Details

Key Features

Parametric specs for Step-Down Switching Regulators
VIN (V) (min) 4.5
VIN (V) (max) 40
VOUT1 (V) (min) 2.5
VOUT1 (V) (max) 6
IOUT1 (A) (max) 10
Switch Type External
Preset VOUT (V) 5
Output Adjust. Method Preset
Resistor
Synchronous Switching? Yes
# DC-DC Outputs 1
Switching Frequency (kHz) 340
Package/Pins SOIC (N)/16
Budgetary
Price (See Notes)
6.21
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Simplified Block Diagram

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Parameters

Parametric specs for Step-Down Switching Regulators
VIN (V) (min) 4.5
VIN (V) (max) 40
VOUT1 (V) (min) 2.5
VOUT1 (V) (max) 6
IOUT1 (A) (max) 10
Switch Type External
Preset VOUT (V) 5
Output Adjust. Method Preset
Resistor
Synchronous Switching? Yes
# DC-DC Outputs 1
Switching Frequency (kHz) 340
Package/Pins SOIC (N)/16
Budgetary
Price (See Notes)
6.21

Key Features

  • 96% Efficiency
  • Up to 40V Power Input
  • 2.5V to 6V Adjustable Output
  • Preset 3.3V and 5V Outputs (at up to 10A)
  • 5V Linear-Regulator Output
  • Precision 2.505V Reference Output
  • Automatic Bootstrap Circuit
  • 150kHz/300kHz Fixed-Frequency PWM Operation
  • Programmable Soft-Start
  • 375µA Quiescent Current (VIN = 12V, VOUT = 5V)
  • 1µA Shutdown Current

Applications/Uses

  • Industrial Controls
  • Notebook and Subnotebook Computers

Description

The MAX797H high-performance, step-down DC-DC converter provides main CPU power in battery-powered systems. A 40V rating on the power stage's input allows operation with high-cell-count batteries and a wide range of AC adapters. This buck controller achieves 96% efficiency by using synchronous rectification and Maxim's proprietary Idle Mode™ control scheme to extend battery life at full-load (up to 10A) and no-load outputs. Excellent dynamic response corrects output transients caused by the latest dynamic-clock CPUs within five 300kHz clock cycles. Unique bootstrap circuitry drives inexpensive N-channel MOSFETs, reducing system cost and eliminating the crowbar switching currents found in some PMOS/NMOS switch designs.

The MAX797H has a logic-controlled and synchronizable fixed-frequency, pulse-width-modulating (PWM) operating mode, which reduces noise and RF interference in sensitive mobile-communications and pen-entry applications. The SKIP override input allows automatic switchover to idle-mode operation (for high-efficiency pulse skipping) at light loads, or forces fixed-frequency mode for lowest noise at all loads. The MAX797H is pin compatible with the popular MAX797, but has a higher input voltage range.

The MAX797H comes in a 16-pin narrow SO package.

Simplified Block Diagram

MAX797H: Typical Operating Circuit MAX797H: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .