MAX8672:Complete Backup Management IC for NiMH Batteries

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.

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
MAX8672: Typical Operating Circuit
MAX8672: Typical Operating Circuit
Applications/Uses
  • PDA, Palmtop, and Wireless Handhelds
  • Smart Cell Phones
DataSheet
titleDownload file
MAX8672 Data SheetMAX8672.pdf
Parametrics
Part NumberReset Thresh.
(V)
ICC
(µA)
Oper. Temp.
(°C)
Package/PinsBudgetary
Price
maxSee Notes
MAX86721.8 to 2.5
2.5 to 3.3
5-40 to +85TDFN-EP/14$2.28 @1k
Design kits & evaluation modules
Related Products
  • MAX8661:High-Efficiency, Low-IQ, PMICs with Dynamic Voltage Management for Mobile Applications
  • MAX8660:High-Efficiency, Low-IQ, PMICs with Dynamic Voltage Management for Mobile Applications
  • MAX8588:High-Efficiency, Low-IQ PMIC with Dynamic Core for PDAs and Smartphones
  • MAX8568A:Complete Backup-Management ICs for Lithium and NiMH Batteries
  • MAX8568B:Complete Backup-Management ICs for Lithium and NiMH Batteries
Ordering Information
Part NumberStatusRecommended ReplacementPackageTempRoHS
MAX8672ETD+ActiveTDFN-EP,;14 pin;9.6 mm²-40°C to +85°CLead Free
MAX8672ETD+TActiveTDFN-EP,;14 pin;9.6 mm²-40°C to +85°CLead Free
MAX8672.pdf MAX8672
MAX8672.pdf MAX8672