MAX8672

PRODUCTION

Complete Backup Management IC for NiMH Batteries

Data Sheet (Rev. 0) Product Selection Table

Part Models: 2
1ku List Price: Starting From $2.97

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Overview

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

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.

Applications

PDA, Palmtop, and Wireless Handhelds
Smart Cell Phones

Part Models: 2
1ku List Price: Starting From $2.97

Documentation

Data Sheet 1

MAX8672: Complete Backup Management IC for NiMH Batteries Data Sheet (Rev.0) 11/16/2006

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.

Part Model	Pin/Package Drawing	Documentation	CAD Symbols, Footprints, and 3D Models
MAX8672ETD+	Thin Dual Flatpack No Leads	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys
MAX8672ETD+T	Thin Dual Flatpack No Leads	Material Declaration Reliablity Data Package Resources	Ultra Librarian SamacSys

Part Models	Product Lifecycle	PCN

Aug 2, 2025 - 2505 PIN/ERRATA
		pcn_2505
MAX8672ETD+	PRODUCTION	pcn_2505
Jun 20, 2016 - 1612 ASSEMBLY
		pcn_1612
MAX8672ETD+	PRODUCTION
MAX8672ETD+T	PRODUCTION

This is the most up-to-date revision of the Data Sheet.

Software Resources

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Hardware Ecosystem

Parts	Product Life Cycle	Description
Battery Charger ICs 2
MAX8568B		Complete Backup-Management ICs for Lithium and NiMH Batteries
MAX8568A		Complete Backup-Management ICs for Lithium and NiMH Batteries
Switching Regulators & Controllers 3
MAX8588		High-Efficiency, Low-I_Q PMIC with Dynamic Core for PDAs and Smartphones
MAX8661	PRODUCTION	High-Efficiency, Low-I_Q, PMICs with Dynamic Voltage Management for Mobile Applications

MAX8660

PRODUCTION

High-Efficiency, Low-I_Q, PMICs with Dynamic Voltage Management for Mobile Applications

Evaluation Kits

Evaluation Kit for the MAX8672

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Features and Benefits

2.7V to 5.5V Input-Voltage Range

Charges One- or Two-Cell NiMH Backup Batteries

Programmable Charge Voltage and Current

Programmable Undervoltage-Lockout (UVLO) Threshold

Programmable Charge Timer

Two Backup Output Voltages:

3.05V (Fixed), 20mA Step-Up DC-DC Converter

1.75V (Adjustable), 20mA LDO

14-Pin, 3mm x 3mm TDFN Package

Lead-Free EV Kit

Fully Assembled and Tested

Product Details

The MAX8672 evaluation kit (EV kit) is a fully assembled and tested PCB that evaluates the MAX8672 backup-management IC for NiMH batteries. The MAX8672 EV kit charges one- or two-cell NiMH batteries, with the EV kit configured for two-cell applications. Maximum battery-charge voltage, standard-charge current, and trickle-charge current are preprogrammed to 3V, 3mA, and 450µA, respectively, using external resistors. The programmable charge timer is set to 480 minutes. An adjustable battery undervoltage-lockout (UVLO) threshold is preset to 1.6V and shuts down battery-backup functions.

To support system-supply voltages, the MAX8672 EV kit provides two outputs. Low-voltage backup cells are stepped up to a fixed 3.05V by a low quiescent-current synchronous-rectified step-up DC-DC converter capable of delivering up to 20mA. A low-dropout (LDO) output is set to 1.75V and is capable of providing up to 20mA. The LDO output voltage is adjustable with external resistors.

The MAX8672 EV kit also features a thermistor input to monitor battery temperature (negative temperature coefficient (NTC) thermistor not included). To simulate a 100kΩ thermistor at T_A = +25°C, the EV kit comes with a 100kΩ resistor installed. See the Thermistor Monitor section for details.

The MAX8672 EV kit comes fully assembled and tested and has an operating temperature range of -40°C to +85°C.