19-2423; Rev 2; 1/03
Bidirectional, High-Side, Current-Sense
Amplifiers with Reference
General Description
Features
ꢀ Bidirectional, Compact, Current-Sense Solution
ꢀ Total Output Error Less than 1.5%
The MAX4069–MAX4072 low-cost, bidirectional, high-
side, current-sense amplifiers are ideal for monitoring
battery charge and discharge currents in notebooks,
cell phones, and other portable equipment. They fea-
ture up to 24V input common-mode voltage range, low
100µA supply current (which drops to only 10µA in
shutdown), and a total output error of less than 1.5%.
The wide 1.35V to 24V input common-mode range is
independent of the supply voltage, ensuring that the
current-sense feedback remains accurate even when
connected to a battery pack in deep discharge.
ꢀ Selectable Gain of 50V/V or 100V/V
ꢀ Wide 1.35V to 24V Common-Mode Range
Independent of Supply Voltage
ꢀ 2.7V to 24V Single-Supply Operation
ꢀ Internal Precision Reference
Adjustable (MAX4069)
2.50V (MAX4070)
To achieve maximum flexibility, an external current-sense
resistor is used along with a Gain Select pin to choose
either 50V/V or 100V/V. A single output pin continuously
monitors the transition from charge to discharge and
avoids the need for a separate polarity output. The
MAX4070 contains an internal 2.5V reference. The
charging current is represented by an output voltage
1.50V (MAX4071)
ꢀ Low 100µA Supply Current
ꢀ 10µA Supply Current in Shutdown
ꢀ Available in Space-Saving Packages
8-Pin Thin QFN (MAX4070/MAX4071/MAX4072)
8-Pin µMAX (MAX4070/MAX4071MAX4072)
10-Pin µMAX (MAX4069)
from 2.5V to V , while discharge current is given from
CC
2.5V to GND. The MAX4071 is similar, but with a refer-
ence voltage of 1.5V. The MAX4069 has an adjustable
reference voltage, set by two external resistors. The
MAX4072 has an input for an external reference.
Ordering Information
TOP
MARK
PART
TEMP RANGE PIN-PACKAGE
The MAX4069/MAX4071/MAX4072 operate from a 2.7V to
24V single supply. The MAX4070 operates from a 3.6V to
24V single supply. All devices are specified over the
automotive operating temperature range, -40°C to
+125°C. The MAX4070/MAX4071/MAX4072 are available
in 8-pin µMAX and 8-pin thin QFN packages. The
MAX4069 is available in a 10-pin µMAX package.
MAX4069AUB -40°C to +125°C 10 µMAX
MAX4070AUA -40°C to +125°C 8 µMAX
—
—
MAX4070ATA
MAX4071AUA -40°C to +125°C 8 µMAX
MAX4071ATA -40°C to +125°C 8 Thin QFN-EP*
MAX4072AUA -40°C to +125°C 8 µMAX
MAX4072ATA -40°C to +125°C 8 Thin QFN-EP*
*EP = Exposed paddle.
-40°C to +125°C 8 Thin QFN-EP*
ABN
—
ABO
—
Applications
ABP
Notebook Fuel Gauging
Smart-Battery Packs/Chargers
Motor Control
Typical Operating Circuit
FROM BATTERY
CHARGER
Power-Management Systems
Cell-Phone Battery-Current Monitoring
R
SENSE
V
= 1.35V TO 24V
BATT
Selector Guide
RS-
RS+
LOAD
SUPPLY
VOLTAGE
RANGE (V)
COMMON-
MODE RANGE
(V)
V
= 3.6V TO 24V
V
CC
CC
PART
REFERENCE
MAX4070
MAX4069
MAX4070
MAX4071
MAX4072
ADJUSTABLE
2.5V
2.7 to 24
3.6 to 24
2.7 to 24
2.7 to 24
1.35 to 24
1.35 to 24
1.35 to 24
1.35 to 24
GSEL
OUT
TO ADC
1.5V
SHDN
REFOUT
2.5V
EXTERNAL
GND
Pin Configurations appear at end of data sheet.
________________________________________________________________ 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.