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4.5V to 42V Input, High-Efficiency, Iso-Buck DC-DC Converter

Reduces External Components and Cost for DC-DC Isolation

Product Details

Key Features

Applications/Uses

Parametric specs for Step-Down/Up Switching Regulators
VIN (V) (min) 4.5
VIN (V) (max) 42
VOUT1 (V) (min) 0.9
VOUT1 (V) (max) 42
Switch Type Internal
VOUT1 Tolerance (±%) 1.7
Output Adjust. Method Resistor
Synchronous Switching? Yes
Power Good Signal Yes
ICC (mA) (max) 1.95
# DC-DC Outputs 1
Alternate Topology Step-Down
Step-Up
Switching Frequency (kHz) 200
Design Tools EE-Sim
Package/Pins TDFN/10
Oper. Temp. (°C) -40 to +125
Parametric specs for Isolated Power Supplies
VIN (V) (min) 4.5
VIN (V) (max) 42
Topology Flyback
Application (VIN) Base Station (24V)
Industrial (24V)
Switch Type Internal
Control Loop Current Mode
Feedback Primary Side
Switching Frequency (kHz) 200
Duty Cycle (%) (max) 97.5
Oper. Temp. (°C) -40 to +125
Package/Pins TDFN/10
Budgetary
Price (See Notes)
1.56
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Simplified Block Diagram

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Parameters

Parametric specs for Step-Down/Up Switching Regulators
VIN (V) (min) 4.5
VIN (V) (max) 42
VOUT1 (V) (min) 0.9
VOUT1 (V) (max) 42
Switch Type Internal
VOUT1 Tolerance (±%) 1.7
Output Adjust. Method Resistor
Synchronous Switching? Yes
Power Good Signal Yes
ICC (mA) (max) 1.95
# DC-DC Outputs 1
Alternate Topology Step-Down
Step-Up
Switching Frequency (kHz) 200
Design Tools generateDesignEESIMUrl('http://maxim.transim.com/pwm2/designreq/Index?partId=9816', '')
Package/Pins TDFN/10
Oper. Temp. (°C) -40 to +125
Parametric specs for Isolated Power Supplies
VIN (V) (min) 4.5
VIN (V) (max) 42
Topology Flyback
Application (VIN) Base Station (24V)
Industrial (24V)
Switch Type Internal
Control Loop Current Mode
Feedback Primary Side
Switching Frequency (kHz) 200
Duty Cycle (%) (max) 97.5
Oper. Temp. (°C) -40 to +125
Package/Pins TDFN/10
Budgetary
Price (See Notes)
1.56

Key Features

  • Reduces External Components and Total Cost
    • No OptoCoupler
    • Synchronous Primary Operation
    • All-Ceramic Capacitors, Compact Layout
  • Reduces Number of DC-DC Regulators to Stock
    • Wide 4.5V to 42V Input
    • 0.9V to 0.96 x VIN Primary Output Voltage
    • Delivers Up to 5W Output Power
  • Reduces Power Dissipation
    • Peak Efficiency > 90%
    • 0.9µA (typ) Shutdown Current
  • Operates Reliably in Adverse Industrial Environments
    • Peak and Sink Current-Limit Protection
    • ±1.7% Feedback Accuracy
    • Programmable EN/UVLO Threshold
    • Adjustable Soft-Start
    • Overtemperature Protection
    • -40°C to +125°C Operation
  • Short-Circuit Protection
    • MAX17681A Supports Robust Secondary-Side Short-Circuit Protection
    • MAX17681A Is Recommended for All New Designs

Applications/Uses

  • Floating Power Supply Generation
  • Isolated Fieldbus Interfaces
  • Isolated Power Supplies in Medical Equipment
  • PLC I/O Modules
  • Smart Meters

Description

The MAX17681/MAX17681A is a high-voltage, high-efficiency, iso-buck DC-DC converter designed to provide isolated power up to 5W. The device operates over a wide 4.5V to 42V input and uses primary-side feedback to regulate the output voltage.

MAX17681/MAX17681A uses peak-current-mode control. The low-resistance, on-chip MOSFETs ensure high efficiency at full load while simplifying the PCB layout.

The MAX17681/MAX17681A devices generate a well regulated primary side voltage which is then scaled by a suitable transformer turns ratio to derive isolated secondary output rails. While both MAX17681 and MAX17681A support primary side overcurrent protection, the MAX17681A is an enhanced design that supports robust secondary-side overcurrent protection as well.

The MAX17681/MAX17681A is available in a compact 10-pin (3mm x 2mm) TDFN package. Simulation models are available.



How to Shrink Your Isolated Power Design with the MAX17681 Iso Buck Technology

Simplified Block Diagram

MAX17681: Application Circuit MAX17681: Application Circuit Zoom icon

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 .