MAX4172 Datasheet, PDF (1/8 Pages) Maxim Integrated Products – Low-Cost, Precision, High-Side Current-Sense Amplifier

19-1184; Rev 0; 12/96
Low-Cost, Precision, High-Side
Current-Sense Amplifier
_______________General Description
The MAX4172 is a low-cost, precision, high-side current-
sense amplifier for portable PCs, telephones, and other
systems where battery/DC power-line monitoring is criti-
cal. High-side power-line monitoring is especially useful in
battery-powered systems, since it does not interfere with
the battery charger’s ground path. Wide bandwidth
and ground-sensing capability make the MAX4172
suitable for closed-loop battery-charger and general-
purpose current-source applications. The 0V to 32V input
common-mode range is independent of the supply volt-
age, which ensures that current-sense feedback remains
viable, even when connected to a battery in deep dis-
charge.
To provide a high level of flexibility, the MAX4172 func-
tions with an external sense resistor to set the range of
load current to be monitored. It has a current output that
can be converted to a ground-referred voltage with a sin-
gle resistor, accommodating a wide range of battery volt-
ages and currents.
An open-collector power-good output (PG) indicates
when the supply voltage reaches an adequate level to
guarantee proper operation of the current-sense amplifi-
er. The MAX4172 operates with a 3.0V to 32V supply
voltage, and is available in a space-saving, 8-pin µMAX
or SO package.
________________________Applications
Portable PCs: Notebooks/Subnotebooks/Palmtops
Battery-Powered/Portable Equipment
Closed-Loop Battery Chargers/Current Sources
Smart-Battery Packs
Portable/Cellular Phones
Portable Test/Measurement Systems
Energy Management Systems
__________________Pin Configuration
TOP VIEW
RS+ 1
RS- ²
N.C. 3
N.C. 4
MAX4172
8 V+
7 PG
6 OUT
5 GND
____________________________Features
o Low-Cost, High-Side Current-Sense Amplifier
o ±0.5% Typical Full-Scale Accuracy Over
Temperature
o 3V to 32V Supply Operation
o 0V to 32V Input Range—Independent of
Supply Voltage
o 800kHz Bandwidth [V_SENSE = 100mV (1C)]
200kHz Bandwidth [V_SENSE = 6.25mV (C/16)]
o Available in Space-Saving µMAX and SO
Packages
______________Ordering Information
PART
TEMP. RANGE
MAX4172ESA
-40°C to +85°C
MAX4172EUA
-40°C to +85°C
*Contact factory for availability.
PIN-PACKAGE
8 SO
8 µMAX*
__________Typical Operating Circuit
UNREGULATED
DC SUPPLY
3V TO 32V
LOW-COST
SWITCHING
REGULATOR
R_SENSE
50mΩ
V_SENSE
0V TO 32V
2A
ANALOG OR
LOGIC SUPPLY
RS+
RS-
V+
PG
MAX4172
OUT
GND
FEEDBACK LOOP
V_OUT = 500mV/A
100k
POWER GOOD LOAD/
BATTERY
I_OUT =
V_SENSE / 100Ω
R_OUT
1k
µMAX/SO
LOW-COST BATTERY CHARGER/CURRENT SOURCE
________________________________________________________________ Maxim Integrated Products 1
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