Datasheet MAX471 (Maxim) - 2

19-0335; Rev 2; 12/96
Precision, High-Side Current-Sense Amplifiers MAX471/MAX472 _______________General Description ____________________________Features
The MAX471/MAX472 are complete, bidirectional, high- ♦
Complete High-Side Current Sensing
side current-sense amplifiers for portable PCs, tele- phones, and other systems where battery/DC ♦
Precision Internal Sense Resistor (MAX471)
power-line monitoring is critical. High-side power-line ♦
2% Accuracy Over Temperature
monitoring is especially useful in battery-powered sys- tems, since it does not interfere with the ground paths ♦
Monitors Both Charge and Discharge
of the battery chargers or monitors often found in ♦
3A Sense Capability with Internal Sense Resistor
“smart” batteries.
(MAX471)
The MAX471 has an internal 35mΩ current-sense resis- ♦ tor and measures battery currents up to ±3A. For appli-
Higher Current-Sense Capability with External
cations requiring higher current or increased flexibility,
Sense Resistor (MAX472)
the MAX472 functions with external sense and gain-set- ♦
100µA Max Supply Current
ting resistors. Both devices have a current output that can be converted to a ground-referred voltage with a ♦
18µA Max Shutdown Mode
single resistor, allowing a wide range of battery volt- ♦
3V to 36V Supply Operation
ages and currents. ♦
8-Pin DIP/SO Packages
An open-collector SIGN output indicates current-flow direction, so the user can monitor whether a battery is being charged or discharged. Both devices operate from 3V to 36V, draw less than 100µA over tempera-
______________Ordering Information
ture, and include a 18µA max shutdown mode.
PART TEMP. RANGE PIN-PACKAGE ________________________Applications MAX471
CPA 0°C to +70°C 8 Plastic DIP MAX471CSA 0°C to +70°C 8 SO Portable PCs: MAX471EPA -40°C to +85°C 8 Plastic DIP Notebooks/Subnotebooks/Palmtops MAX471ESA -40°C to +85°C 8 SO Smart Battery Packs
MAX472
CPA 0°C to +70°C 8 Plastic DIP Cellular Phones MAX472CSA 0°C to +70°C 8 SO Portable Phones MAX472EPA -40°C to +85°C 8 Plastic DIP Portable Test/Measurement Systems MAX472ESA -40°C to +85°C 8 SO Battery-Operated Systems Energy Management Systems
__________Typical Operating Circuit _________________Pin Configurations
RS+ RS- ILOAD TO TOP VIEW LOAD or CHARGER RS+ RS- LOGIC SUPPLY SHDN 1 8 OUT 100k RS+ 2 7 RS- 3V MAX471 MAX471 TO SIGN DISCHARGE/CHARGE RS+ 3 6 RS- 36V OUT VOUT (1V/A) GND 4 5 SIGN SHDN GND ILOAD 2000 2k
DIP/SO
MAX472 Pin Configuration continued on last page.
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