1. Products
  2. Power Management
  3. Switching Regulators
  4. Step-Down (Buck) Regulators
  5. External Power Switch Buck Controllers
  6. MAX1634


Features and Benefits

  • 96% Efficiency
  • +4.2V to +30V Input Range
  • 2.5V to 5.5V Dual Adjustable Outputs
  • Selectable 3.3V and 5V Fixed or Adjustable Outputs (Dual Mode™)
  • 12V Linear Regulator
  • Adjustable Secondary Feedback (MAX1631/MAX1634)
  • 5V/50mA Linear Regulator Output
  • Precision 2.5V Reference Output
  • Programmable Power-Up Sequencing
  • Power-Good (active-low RESET) Output
  • Output Overvoltage Protection (MAX1630/MAX1631/MAX1632)
  • Output Undervoltage Shutdown (MAX1630/MAX1631/MAX1632)
  • 200kHz/300kHz Low-Noise, Fixed-Frequency Operation
  • Low-Dropout, 99% Duty-Factor Operation
  • 2.5mW Typical Quiescent Power (+12V input, both SMPSs on)
  • 4µA Typical Shutdown Current
  • 28-Pin SSOP Package

Product Details

The MAX1630–MAX1635 are buck-topology, step-down, switch-mode, power-supply controllers that generate logic-supply voltages in battery-powered systems. These high-performance, dual/triple-output devices include on-board power-up sequencing, power-good signaling with delay, digital soft-start, secondary winding control, low-dropout circuitry, internal frequency-compensation networks, and automatic bootstrapping.

Up to 96% efficiency is achieved through synchronous rectification and Maxim's proprietary Idle Mode™ control scheme. Efficiency is greater than 80% over a 1000:1 load-current range, which extends battery life in system-suspend or standby mode. Excellent dynamic response corrects output load transients caused by the latest dynamic-clock CPUs within five 300kHz clock cycles. Strong 1A on-board gate drivers ensure fast external N-channel MOSFET switching.
These devices feature a logic-controlled and synchronizable, fixed-frequency, pulse-width-modulation (PWM) operating mode. This reduces noise and RF interference in sensitive mobile communications and pen-entry applications. Asserting the active-low SKIP pin enables fixed-frequency mode, for lowest noise under all load conditions.
The MAX1630–MAX1635 include two PWM regulators, adjustable from 2.5V to 5.5V with fixed 5.0V and 3.3V modes. All these devices include secondary feedback regulation, and the MAX1630/MAX1632/MAX1633/ MAX1635 each contain 12V/120mA linear regulators. The MAX1631/MAX1634 include a secondary feedback input (SECFB), plus a control pin (STEER) that selects which PWM (3.3V or 5V) receives the secondary feedback signal. SECFB provides a method for adjusting the secondary winding voltage regulation point with an external resistor divider, and is intended to aid in creating auxiliary voltages other than fixed 12V.

The MAX1630/MAX1631/MAX1632 contain internal output overvoltage and undervoltage protection features.


  • Desktop CPU Local DC-DC Converters
  • Notebook and Subnotebook Computers
  • PDAs and Mobile Communicators

Product Lifecycle icon-not-recommended Not Recommended for New Designs

This designates products ADI does not recommend broadly for new designs.

Evaluation Kits (3)

Product Recommendations

MAX1634 Companion Parts

Recommended Related Parts

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.

Part Number Material Declaration Reliability Data Pin/Package Drawing CAD Symbols, Footprints & 3D Models
MAX1634CAI+ Material Declaration Reliability Data 28-SSOP-5.3_MM
MAX1634EAI+ Material Declaration Reliability Data 28-SSOP-5.3_MM
MAX1634EAI+T Material Declaration Reliability Data 28-SSOP-5.3_MM
Wafer Fabrication Data MAX1634 Reliability Data

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