Rainbow Electronics MAX1873 - Manual

General Description
The low-cost MAX1873R/S/T provides all functions
needed to simply and efficiently charge 2-, 3-, or 4-
series lithium-ion cells at up to 4A or more. It provides a
regulated charging current and voltage with less than
±0.75% total voltage error at the battery terminals. An
external P-channel MOSFET operates in a step-down
DC-DC configuration to efficiently charge batteries in
low-cost designs.
The MAX1873R/S/T regulates the battery voltage and
charging current using two control loops that work
together to transition smoothly between voltage and
current regulation. An additional control loop limits cur-
rent drawn from the input source so that AC adapter
size and cost can be minimized. An analog voltage out-
put proportional to charging current is also supplied so
that an ADC or microcontroller can monitor charging
current.
The MAX1873 may also be used as an efficient current-
limited source to charge NiCd or NiMH batteries in mul-
tichemistry charger designs. The MAX1873R/S/T is
available in a space-saving 16-pin QSOP package. Use
the evaluation kit (MAX1873EVKIT) to help reduce
design time.
Applications
Notebook Computers
Portable Internet Tablets
2-, 3-, or 4-cell Li+ Battery Pack Chargers
6-, 9-, or 10-cell Ni Battery Pack Chargers
Hand-Held Instruments
Portable Desktop Assistants (PDAs)
Desktop Cradle Chargers
Features
♦ Low-Cost and Simple Circuit
♦ Charges 2-, 3-, or 4-Series Lithium-Ion Cells
♦ AC Adapter Input-Current-Limit Loop
♦ Also Charges Ni-Based Batteries
♦ Analog Output Monitors Charge Current
♦ ±0.75% Battery-Regulation Voltage
♦ 5µA Shutdown Battery Current
♦ Input Voltage Up to 28V
♦ 200mV Dropout Voltage/100% Duty Cycle
♦ Adjustable Charging Current
♦ 300kHz PWM Oscillator Reduces Noise
♦ Space-Saving 16-Pin QSOP
♦ MAX1873 Evaluation Kit Available to Speed
Designs
MAX1873
Simple Current-Limited Switch-Mode
Li+ Charger Controller
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-2099; Rev 0; 7/01
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.
EVALUATIO
N KIT AVA
ILABLE
PART TEMP. RANGE PIN-PACKAGE
MAX1873REEE -40°C to +85°C 16 QSOP
MAX1873SEEE -40°C to +85°C 16 QSOP
MAX1873TEEE -40°C to +85°C 16 QSOP
Selector Guide
PART SERIES CELLS TO CHARGE
MAX1873REEE 2-Cell Li+ or 5- or 6-cell Ni Battery
MAX1873SEEE 3-Cell Li+ or 7- or 9-cell Ni Battery
MAX1873TEEE 4-Cell Li+ 10-cell Ni Battery Packs
MAX1873
GND
VADJ
REF
ICHG/EN
IOUT
DCIN
VH VL CSSP
CSSN
SYSTEM
LOAD
VIN 9V TO
28V
(9V MIN
FOR 2-
CELLS)
4V OUT PER
200mV ON R CS
EXT
BATT
CSB
CCI
CCS
CCV
2- TO 4-CELL
Li+
Typical Operating Circuit
Pin Configuration appears at end of data sheet.