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2.5V–5.0V, 0.5A/2.5A Reversible Buck/Boost Regulator for Backup Power Applications

Continua Family of Backup Power Regulators Using Super Capacitor or Capacitor Bank

Product Details

The MAX38888 is a storage capacitor or capacitor bank backup regulator designed to efficiently transfer power between a storage element and a system supply rail in reversible buck and boost operations using the same inductor.

When the main supply is present and above the minimum system supply voltage, the regulator operates in buck mode and charges the storage element at up to 500mA peak inductor current. Once the storage element is charged, the circuit draws only 2.5µA of current while it maintains the super capacitor or other storage element in its ready state. When the main supply is removed, the regulator operates in boost mode and prevents the system from dropping below the minimum operating voltage, discharging the storage element at up to 2.5A peak inductor current.

The MAX38888 is externally programmable for minimum and maximum voltage of the storage element, such as super capacitor, minimum system voltage, and maximum charge and discharge currents. The internal DC/DC converter requires only a 1µH inductor.

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Key Features

  • 2.5V to 5V System Output Voltage
  • 0.8V to 4.5V Cap Voltage Range
  • Up to 2.5A Peak Inductor Discharge Current
  • Programmable Voltage and Current Thresholds
  • ±2% Threshold Accuracy
  • Up to 95% Efficiency, Charge or Discharge
  • 2.5µA Ready Quiescent Current
  • Small Solution Size
    • 3mm x 3mm x 0.75mm TDFN Package

Applications/Uses

  • Handheld Industrial Equipment
  • Portable Computers
  • Portable Devices with a Removable Battery
Parametric specs for Battery Chargers
Charging VIN (V) (max) 5.5
Max. ICHG (A) 2.5
Cell Chemistry Supercapacitor
Charger (V) 0.8 to 5
Oper. Temp. (°C) -40 to +125
Package/Pins TDFN-CU/14
Budgetary
Price (See Notes)
$3.13 @1k
Parametric specs for Step-Up Switching Regulators
VIN (V) (min) 0.8
VIN (V) (max) 4.5
VOUT1 (V) (min) 2.5
VOUT1 (V) (max) 5
IOUT1 (A) (max) 2.5
Switch Type Internal
Output Adjust. Method Resistor
ICC (mA) (typ) 0.035
# DC-DC Outputs 1
Switching Frequency (kHz) 2000
Design Tools EE-Sim
Package/Pins TDFN-CU/14
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Simplified Block Diagram

MAX38888: Typical Application Circuit MAX38888: Typical Application Circuit Zoom icon

Technical Docs

Design & Development

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Description

The MAX38888 evaluation kit (EV kit) evaluates the MAX38888 IC. The MAX38888 is a super cap backup regulator designed to transfer power between a super cap and a system supply rail. When the main battery is present and above the minimum system supply voltage, the regulator charges the super cap at up to a 500mA rate. Once the super cap is charged, the circuit draws only 2.5μA of current while it maintains the super cap in its ready state. When the main battery is removed, the regulator prevents the system from dropping below the minimum operating voltage, discharging the super cap at up to a 2.5A rate. The MAX38888 is externally programmable for minimum and maximum super cap voltage, minimum system voltage, and maximum charge and discharge currents. The internal DC/DC converter requires only a 1μH inductor.

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Features

  • 2.99V to 3.36V System Output Voltage Range
  • 1.42V to 2.71V Super Cap Voltage Range
  • 2.5A Peak Discharge Current
  • Resistor Adjustable Voltage and Current Thresholds
  • Proven 2-Layer 2oz Copper PCB Layout
  • Demonstrates Compact Solution Size
  • Fully Assemble and Tested

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Tools & Models

EE-Sim: Design & Simulate MAX38888

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Parameters

Parametric specs for Battery Chargers
Charging VIN (V) (max) 5.5
Max. ICHG (A) 2.5
Cell Chemistry Supercapacitor
Charger (V) 0.8 to 5
Oper. Temp. (°C) -40 to +125
Package/Pins TDFN-CU/14
Budgetary
Price (See Notes)
$3.13 @1k
Parametric specs for Step-Up Switching Regulators
VIN (V) (min) 0.8
VIN (V) (max) 4.5
VOUT1 (V) (min) 2.5
VOUT1 (V) (max) 5
IOUT1 (A) (max) 2.5
Switch Type Internal
Output Adjust. Method Resistor
ICC (mA) (typ) 0.035
# DC-DC Outputs 1
Switching Frequency (kHz) 2000
Design Tools EE-Sim
Package/Pins TDFN-CU/14

Key Features

  • 2.5V to 5V System Output Voltage
  • 0.8V to 4.5V Cap Voltage Range
  • Up to 2.5A Peak Inductor Discharge Current
  • Programmable Voltage and Current Thresholds
  • ±2% Threshold Accuracy
  • Up to 95% Efficiency, Charge or Discharge
  • 2.5µA Ready Quiescent Current
  • Small Solution Size
    • 3mm x 3mm x 0.75mm TDFN Package

Applications/Uses

  • Handheld Industrial Equipment
  • Portable Computers
  • Portable Devices with a Removable Battery

Description

The MAX38888 is a storage capacitor or capacitor bank backup regulator designed to efficiently transfer power between a storage element and a system supply rail in reversible buck and boost operations using the same inductor.

When the main supply is present and above the minimum system supply voltage, the regulator operates in buck mode and charges the storage element at up to 500mA peak inductor current. Once the storage element is charged, the circuit draws only 2.5µA of current while it maintains the super capacitor or other storage element in its ready state. When the main supply is removed, the regulator operates in boost mode and prevents the system from dropping below the minimum operating voltage, discharging the storage element at up to 2.5A peak inductor current.

The MAX38888 is externally programmable for minimum and maximum voltage of the storage element, such as super capacitor, minimum system voltage, and maximum charge and discharge currents. The internal DC/DC converter requires only a 1µH inductor.

Mobile App

Simplified Block Diagram

MAX38888: Typical Application Circuit MAX38888: Typical Application Circuit 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