Back-Up Management NiMH 0.1mA to 20mA 1.5V to 3.05V 14-Pin TDFN EP

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.

• 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 BatteryUVLO
• 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 PreventsOvercharge