1. Products
  2. Power Management
  3. Switching Regulators
  4. Step-Down (Buck) Regulators
  5. External Power Switch Buck Controllers
  6. MAX1631A


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 (MAX1631A/MAX1634A)
  • 5V/50mA Linear Regulator Output
  • Precision 2.5V Reference Output
  • Programmable Power-Up Sequencing
  • Power-Good (Active-Low RESET) Output
  • Output Overvoltage Protection (MAX1630A/MAX1631A/MAX1632A)
  • Output Undervoltage Shutdown (MAX1630A/MAX1631A/MAX1632A)
  • 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 MAX1630A–MAX1635A are buck-topology, stepdown, 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 MAX1630A–MAX1635A 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 MAX1630A/MAX1632A/MAX1633A/MAX1635A each contain 12V/120mA linear regulators. The MAX1631A/MAX1634A 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 MAX1630A/MAX1631A/MAX1632A contain internal output overvoltage and undervoltage protection features. The MAX1630A family has improved RF immunity over the MAX1630 family.


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

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

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
MAX1631AEAI+ Material Declaration Reliability Data 28-SSOP-5.3_MM
MAX1631AEAI+T Material Declaration Reliability Data 28-SSOP-5.3_MM
Wafer Fabrication Data MAX1631A Reliability Data

Sample & Buy

Ordering FAQs

See our Ordering FAQs for answers to questions about online orders, payment options and more.


Buy Now Pricing

(**) Displayed Buy Now Price and Price Range is based on small quantity orders.


List Pricing

(*)The 1Ku list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.


Lead Times

Please see the latest communication from our CCO regarding lead times.



A Sample link will be shown above, next to the part, only for parts that are included in our sample program. Selecting the Sample button will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.

Price Table Help