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Dual Quick-PWM Step-Down Controller with Low-Power LDO, RTC Regulator

Multipurpose Controller Configurable for System Power, Graphics, and Memory Applications in Notebooks

Product Details

The MAX17020 is a dual Quick-PWM™ step-down power-supply (SMPS) controller with synchronous rectification, intended for main 5V/3.3V or I/O 1.5V/1.05V power generation in battery-powered systems. Lowside MOSFET sensing provides a simple low-cost, highly efficient current sense for valley current-limit protection. Combined with the output overvoltage and undervoltage protection features, this current limit ensures robust output supplies.

The 5V/3.3V or 1.5V/1.05V SMPS outputs can save power by operating in pulse-skipping mode or in ultrasonic mode to avoid audible noise. Ultrasonic mode forces the controller to maintain switching frequencies greater than 20kHz at light loads.

An internal 100mA linear regulator can be used to either generate the 5V bias needed for power-up or other lower power "always-on" suspend supplies. An independent bypass input allows automatic bypassing of the linear regulator when the SMPS is active.

This main controller also includes a secondary feedback input that triggers an ultrasonic pulse (DL1 turned on) if the SECFB voltage drops below its threshold voltage. This refreshes an external charge pump driven by DL1 without overcharging the output voltage.

The device includes independent shutdown controls to simplify power-up and power-down sequencing. To prevent current surges at startup, the internal voltage target is slowly ramped up from zero to the final target over a 1ms period. To prevent the output from ringing below ground in shutdown, the internal voltage target is ramped down from its previous value to zero over a 1ms period. Two independent power-good outputs simplify the interface with external controllers.

The MAX17020 is a pin-for-pin replacement of the MAX8778.

Key Features

  • Dual Quick-PWM
  • Internal 100mA 5V or Adjustable Linear Regulator
  • Independent LDO Bypass Input
  • Internal Boost Diodes
  • Secondary Feedback Input Maintains Charge Pump
  • 3.3V 5mA RTC Power (Always On)
  • OUT1: 5V or 1.5V Fixed or 0.7V Adjustable Feedback
  • OUT2: 3.3V or 1.05V Fixed or Dynamic Adjustable
  • Dynamic 0V to 2V REFIN2 Input on Second SMPS
  • 2V ±1% 50µA Reference
  • 6V to 24V Input Range (28V max)
  • Ultrasonic Mode
  • Independent SMPS and LDO Enable Controls
  • Independent SMPS Power-Good Outputs
  • Minimal Component Count

Applications/Uses

  • DDR1, DDR2, DDR3 Power Supplies
  • Game Consoles
  • Graphic Cards
  • I/O System Supply (1.5V and 1.05V Supplies)
  • Low-Power I/O and Chipset Supplies
  • Main System Supply (5V and 3.3V Supplies)
  • Notebook Computers
  • PDAs and Mobile Communicators
  • Telecommunication
  • Two to Four Li+ Cells Battery-Powered Devices
Parametric specs for Step-Down Switching Regulators
VIN (V) (min) 6
VIN (V) (max) 24
VOUT1 (V) (min) 0
VOUT1 (V) (max) 5.5
IOUT1 (A) (max) 10
Switch Type External
Preset VOUT (V) 5
Output Adjust. Method Dyn. REF In
Preset
Resistor
Synchronous Switching? Yes
Power Good Signal Yes
# DC-DC Outputs 2
Switching Frequency (kHz) 500
Package/Pins TQFN/32
Budgetary
Price (See Notes)
$2.44 @1k
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Simplified Block Diagram

MAX17020: Functional Diagram MAX17020: Functional Diagram Zoom icon

Technical Docs

Design & Development

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Description

The MAX17020 evaluation kit (EV kit) demonstrates the MAX17020's standard application circuit. This dual Quick-PWM™ synchronous DC-DC converter steps down high-voltage batteries and/or AC adapters, generating main supplies for notebook computers. The MAX17020 EV kit provides dual 1.5V (VOUT1) and 1.05V (VOUT2) output voltages from a 6V to 24V battery-input range. It delivers at least 6A output current for the 1.5V output, and 10A for the 1.05V output. Both outputs are adjustable between 0.7V and 5.5V. An external unregulated charge pump generates an 8V (VSEC) auxiliary voltage capable of delivering 2mA from the 1.5V output.

The MAX17020 also has an internal fixed 5V low-dropout (LDO) linear regulator capable of supplying 100mA, and an always-on 3.3V, 5mA real-time clock (RTC) supply.

The MAX17020 EV kit operates at 400kHz/300kHz switching frequency (1.5V/1.05V, respectively) and has superior line- and load-transient response.

For 5V and 3.3V output evaluation, the MAX8778 EV kit can be used. The MAX17020 is a pin-for-pin replacement of the MAX8778.

View Details

Features

  • 6V to 24V Input Range
  • 3.3V, 5mA RTC Power (Always On)
  • Internal 5V, 100mA Linear Regulator (Adjustable from 0.6V to 4V)
  • Output Voltages:
    • 1.05V at 10AMIN (VOUT2, Dynamic Adjustable from 0 to 2V) or Preset 3.3V
    • 1.5V at 6AMIN (VOUT1, Adjustable from 0.7V to 5.5V)
    • 8VMIN at 2mA (Charge-Pump Output)
  • Dynamic 0 to 2V REFIN2 Input on Second Output
  • 400kHz/300kHz Switching Frequency (1.5V/1.05V, Respectively)
  • Power-Good (PGOOD1 and PGOOD2) Indicators
  • Secondary Feedback Input Maintains Charge Pump
  • 32-Pin, 5mm x 5mm Thin QFN Package
  • Fully Assembled and Tested

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Parameters

Parametric specs for Step-Down Switching Regulators
VIN (V) (min) 6
VIN (V) (max) 24
VOUT1 (V) (min) 0
VOUT1 (V) (max) 5.5
IOUT1 (A) (max) 10
Switch Type External
Preset VOUT (V) 5
Output Adjust. Method Dyn. REF In
Preset
Resistor
Synchronous Switching? Yes
Power Good Signal Yes
# DC-DC Outputs 2
Switching Frequency (kHz) 500
Package/Pins TQFN/32
Budgetary
Price (See Notes)
$2.44 @1k

Key Features

  • Dual Quick-PWM
  • Internal 100mA 5V or Adjustable Linear Regulator
  • Independent LDO Bypass Input
  • Internal Boost Diodes
  • Secondary Feedback Input Maintains Charge Pump
  • 3.3V 5mA RTC Power (Always On)
  • OUT1: 5V or 1.5V Fixed or 0.7V Adjustable Feedback
  • OUT2: 3.3V or 1.05V Fixed or Dynamic Adjustable
  • Dynamic 0V to 2V REFIN2 Input on Second SMPS
  • 2V ±1% 50µA Reference
  • 6V to 24V Input Range (28V max)
  • Ultrasonic Mode
  • Independent SMPS and LDO Enable Controls
  • Independent SMPS Power-Good Outputs
  • Minimal Component Count

Applications/Uses

  • DDR1, DDR2, DDR3 Power Supplies
  • Game Consoles
  • Graphic Cards
  • I/O System Supply (1.5V and 1.05V Supplies)
  • Low-Power I/O and Chipset Supplies
  • Main System Supply (5V and 3.3V Supplies)
  • Notebook Computers
  • PDAs and Mobile Communicators
  • Telecommunication
  • Two to Four Li+ Cells Battery-Powered Devices

Description

The MAX17020 is a dual Quick-PWM™ step-down power-supply (SMPS) controller with synchronous rectification, intended for main 5V/3.3V or I/O 1.5V/1.05V power generation in battery-powered systems. Lowside MOSFET sensing provides a simple low-cost, highly efficient current sense for valley current-limit protection. Combined with the output overvoltage and undervoltage protection features, this current limit ensures robust output supplies.

The 5V/3.3V or 1.5V/1.05V SMPS outputs can save power by operating in pulse-skipping mode or in ultrasonic mode to avoid audible noise. Ultrasonic mode forces the controller to maintain switching frequencies greater than 20kHz at light loads.

An internal 100mA linear regulator can be used to either generate the 5V bias needed for power-up or other lower power "always-on" suspend supplies. An independent bypass input allows automatic bypassing of the linear regulator when the SMPS is active.

This main controller also includes a secondary feedback input that triggers an ultrasonic pulse (DL1 turned on) if the SECFB voltage drops below its threshold voltage. This refreshes an external charge pump driven by DL1 without overcharging the output voltage.

The device includes independent shutdown controls to simplify power-up and power-down sequencing. To prevent current surges at startup, the internal voltage target is slowly ramped up from zero to the final target over a 1ms period. To prevent the output from ringing below ground in shutdown, the internal voltage target is ramped down from its previous value to zero over a 1ms period. Two independent power-good outputs simplify the interface with external controllers.

The MAX17020 is a pin-for-pin replacement of the MAX8778.

Simplified Block Diagram

MAX17020: Functional Diagram MAX17020: Functional Diagram 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