MAX8672 Datasheet, PDF (1/17 Pages) Maxim Integrated Products – Complete Backup Management IC for NiMH Batteries

19-0653; Rev 0; 11/06
EVAALVUAAILTAIOBNLEKIT
Complete Backup Management
IC for NiMH Batteries
General 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 batter-
ies. A low-quiescent current synchronous-rectified
boost converter and LDO supply up to 20mA during
system backup. The BST output is internally set to regu-
late 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 volt-
age. Charging is controlled by both a timer and ther-
mistor monitor. Battery UVLO prevents excessive
battery discharge and keeps inactive-battery drain cur-
rent below 50nA. In addition, both LDO and boost con-
verter 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 oper-
ation can occur.
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
Pin Configuration
TOP VIEW
14 13 12 11 10 9 8
MAX8672
1234567
TDFN
(3mm x 3mm)
Features
o Charges 1- or 2-Cell NiMH Backup Batteries
o Programmable Charge Current
o DC Trickle Charge Mode for Maximum Cell Life
o Deep-Recovery Charge Restores Cells < 1V
o Programmable Charge Timer
o Programmable Charge-Voltage Limit and Battery
UVLO
o Reverse Current Blocking on BATT, LDO, and
Boost—No Diodes Needed
o No Battery Drain When Off (< 50nA)
o Thermistor Sensing Disables Standard Charge
o Battery Restart Charge Threshold Prevents
Overcharge
Ordering Information
PART
MAX8672ETD+T
PIN-PACKAGE
PKG CODE
14 TDFN-14 (3mm x 3mm) T14334+2
The MAX8672 operates in the -40°C to +85°C extended
operating temperature range.
+Denotes lead-free package.
Typical Operating Circuit
CT
THRM
2.7V TO 5.5V INPUT
MAX8672
IN
CHGV
DR
CHGI
TRKI
BACKUP BATTERY
CONNECTION
FBL
BATT
LDO
UV
BST
GND
LX
1.75V
3.05V
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.