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High-Efficiency, PWM, Step-Down DC-DC Controllers in 16-Pin QSOP

10A DSP/CPU Core Supply with Secondary Outputs in Space-Saving QSOP Package

Product Details

The MAX1652-MAX1655 are high-efficiency, pulse-width-modulated (PWM), step-down DC-DC controllers in small QSOP packages. The MAX1653/MAX1655 also come in 16-pin narrow SO packages that are pin-compatible upgrades to the popular MAX797. Improvements include higher duty-cycle operation for better dropout, lower quiescent supply currents for better light-load efficiency, and an output voltage down to 1V (MAX1655).

The MAX1652-MAX1655 achieve up to 96% efficiency and deliver up to 10A using a unique Idle Mode™ synchronous-rectified PWM control scheme. These devices automatically switch between PWM operation at heavy loads and pulse-frequency-modulated (PFM) operation at light loads to optimize efficiency over the entire output current range. The MAX1653/MAX1655 also feature logic-controlled, forced PWM operation for noise-sensitive applications.

All devices operate with a selectable 150kHz/300kHz switching frequency, which can also be synchronized to an external clock signal. Both external power switches are inexpensive N-channel MOSFETs, which provide low resistance while saving space and reducing cost.

The MAX1652 and MAX1654 have an additional feedback pin that permits regulation of a low-cost second output tapped from a transformer winding. The MAX1652 provides an additional positive output. The MAX1654 provides an additional negative output.

The MAX1652-MAX1655 have a 4.5V to 30V input voltage range. The MAX1652/MAX1653/MAX1654's output range is 2.5V to 5.5V while the MAX1655's output range extends down to 1V. An evaluation kit (MAX1653EVKit) is available to speed designs.

Key Features

  • 96% Efficiency
  • Small, 16-Pin QSOP Package (half the size of a 16-pin narrow SO)
  • Pin-Compatible with MAX797 (MAX1653/MAX1655)
  • Output Voltage Down to 1V (MAX1655)
  • 4.5V to 30V Input Range
  • 99% Duty Cycle for Lower Dropout
  • 170µA Quiescent Supply Current
  • 3µA Logic-Controlled Shutdown
  • Dual, N-Channel, Synchronous-Rectified Control
  • Fixed 150kHz/300kHz PWM Switching, or Synchronized from 190kHz to 340kHz
  • Programmable Soft Start
  • Low-Cost Secondary Outputs (MAX1652/MAX1654)
  • Synchronous rectifier, secondary output regulation, high efficiency over full IOUT range

Applications/Uses

  • Cell Phones
  • Distributed Power
  • Handheld Computers
  • Handy Terminals
  • Mobile Communications
  • Notebook Computers
  • PDAs
Parametric specs for Step-Down Switching Regulators
VIN (V) (min) 4.5
VIN (V) (max) 30
VOUT1 (V) (min) 2.5
VOUT1 (V) (max) 5.5
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 QSOP/16
SOIC (N)/16
Budgetary
Price (See Notes)
$3.69 @1k
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Simplified Block Diagram

MAX1652, MAX1653, MAX1654, MAX1655: Functional Diagram MAX1652, MAX1653, MAX1654, MAX1655: Functional Diagram Zoom icon

Design & Development

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Description

The MAX1653 evaluation kit (EV kit) provides a +3.3V output voltage from a +4.5V to +28V input. It delivers up to 2A output current with greater than 95% efficiency, operates at 300kHz switching frequency, and has superior line- and load-transient response.

This EV kit can be used to evaluate other output voltages in the +2.5V to +5.5V range by changing feedback resistors R2 and R3. It can also be used to evaluate the MAX1655, which has a +1.0V to +5.5V output voltage range.

View Details

Features

  • +4.5V to +28V Input Voltage Range
  • Selectable +3.3V or +5V Output Voltage
  • +2.5V to +5.5V Adjustable Output (MAX1653)
  • +1.0V to +5.5V Adjustable Output (MAX1655)
  • 2A Output Current
  • 3µA IC Shutdown Current
  • 300kHz Switching Frequency
  • Surface-Mount Construction
  • Fully Assembled and Tested

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Parameters

Parametric specs for Step-Down Switching Regulators
VIN (V) (min) 4.5
VIN (V) (max) 30
VOUT1 (V) (min) 2.5
VOUT1 (V) (max) 5.5
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 QSOP/16
SOIC (N)/16
Budgetary
Price (See Notes)
$3.69 @1k

Key Features

  • 96% Efficiency
  • Small, 16-Pin QSOP Package (half the size of a 16-pin narrow SO)
  • Pin-Compatible with MAX797 (MAX1653/MAX1655)
  • Output Voltage Down to 1V (MAX1655)
  • 4.5V to 30V Input Range
  • 99% Duty Cycle for Lower Dropout
  • 170µA Quiescent Supply Current
  • 3µA Logic-Controlled Shutdown
  • Dual, N-Channel, Synchronous-Rectified Control
  • Fixed 150kHz/300kHz PWM Switching, or Synchronized from 190kHz to 340kHz
  • Programmable Soft Start
  • Low-Cost Secondary Outputs (MAX1652/MAX1654)
  • Synchronous rectifier, secondary output regulation, high efficiency over full IOUT range

Applications/Uses

  • Cell Phones
  • Distributed Power
  • Handheld Computers
  • Handy Terminals
  • Mobile Communications
  • Notebook Computers
  • PDAs

Description

The MAX1652-MAX1655 are high-efficiency, pulse-width-modulated (PWM), step-down DC-DC controllers in small QSOP packages. The MAX1653/MAX1655 also come in 16-pin narrow SO packages that are pin-compatible upgrades to the popular MAX797. Improvements include higher duty-cycle operation for better dropout, lower quiescent supply currents for better light-load efficiency, and an output voltage down to 1V (MAX1655).

The MAX1652-MAX1655 achieve up to 96% efficiency and deliver up to 10A using a unique Idle Mode™ synchronous-rectified PWM control scheme. These devices automatically switch between PWM operation at heavy loads and pulse-frequency-modulated (PFM) operation at light loads to optimize efficiency over the entire output current range. The MAX1653/MAX1655 also feature logic-controlled, forced PWM operation for noise-sensitive applications.

All devices operate with a selectable 150kHz/300kHz switching frequency, which can also be synchronized to an external clock signal. Both external power switches are inexpensive N-channel MOSFETs, which provide low resistance while saving space and reducing cost.

The MAX1652 and MAX1654 have an additional feedback pin that permits regulation of a low-cost second output tapped from a transformer winding. The MAX1652 provides an additional positive output. The MAX1654 provides an additional negative output.

The MAX1652-MAX1655 have a 4.5V to 30V input voltage range. The MAX1652/MAX1653/MAX1654's output range is 2.5V to 5.5V while the MAX1655's output range extends down to 1V. An evaluation kit (MAX1653EVKit) is available to speed designs.

Simplified Block Diagram

MAX1652, MAX1653, MAX1654, MAX1655: Functional Diagram MAX1652, MAX1653, MAX1654, MAX1655: Functional Diagram 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