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Complete Backup Management IC for NiMH Batteries

Product Details

Key Features

Parametric specs for Battery Backup Circuits
Reset Thresh. (V) 1.8 to 2.5
2.5 to 3.3
ICC (µA) (max) 5
Oper. Temp. (°C) -40 to +85
Package/Pins TDFN/14
Budgetary
Price (See Notes)
2.97
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Simplified Block Diagram

Technical Docs

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Selecting the Sample button above 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.

Parameters

Parametric specs for Battery Backup Circuits
Reset Thresh. (V) 1.8 to 2.5
2.5 to 3.3
ICC (µA) (max) 5
Oper. Temp. (°C) -40 to +85
Package/Pins TDFN/14
Budgetary
Price (See Notes)
2.97

Key Features

  • Charges 1- or 2-Cell NiMH Backup Batteries
  • Programmable Charge Current
  • DC Trickle Charge Mode for Maximum Cell Life
  • Deep-Recovery Charge Restores Cells < 1V
  • Programmable Charge Timer
  • Programmable Charge-Voltage Limit and Battery UVLO
  • Reverse Current Blocking on BATT, LDO, and Boost—No Diodes Needed
  • No Battery Drain When Off (< 50nA)
  • Thermistor Sensing Disables Standard Charge
  • Battery Restart Charge Threshold Prevents Overcharge

Applications/Uses

  • PDA, Palmtop, and Wireless Handhelds
  • Smart Cell Phones

Description

The MAX8672 complete power manager for backup batteries in smart devices offers feature-programmable battery charging and main-system backup. The device includes a charger for 1- or 2-cell NiMH backup batteries. A low-quiescent current synchronous-rectified boost converter and LDO supply up to 20mA during system backup conditions. The BST output is internally set to regulate at 3.05V. The MAX8672 LDO is powered from the boost converter output and is adjustable from 1.5V to 3.05V.

The MAX8672 features programmable charge current, undervoltage lockout (UVLO), and maximum cell voltage. Charging is controlled by both a timer and thermistor monitor. Battery UVLO prevents excessive battery discharge and keeps inactive-battery drain current below 50nA. In addition, both LDO and boost converter outputs block reverse current so that diodes are not needed when connecting these outputs directly to system supplies. The MAX8672 requires that a valid system supply be present before system backup operation can occur.

Charging is managed by a current source that charges until the battery reaches the programmed voltage limit, or the charge timer expires.

The MAX8672 is available in a 14-pin, 3mm x 3mm TDFN package and is rated for -40°C to +85°C operation.

Simplified Block Diagram

MAX8672: Typical Operating Circuit MAX8672: Typical Operating 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 .

Sampling:
Selecting the Sample button above 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.