MAX471CSA+-MAX471CSA+T-MAX471CSA-T-MAX471ESA+T-MAX472CSA+-MAX472ESA-T Fast Delivery |IC PHOENIX CO.,LIMITED

MAX471ESA+T ,Precision, High-Side Current-Sense AmplifiersGeneral Description ________
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MAX471CSA+-MAX471CSA+T-MAX471CSA-T-MAX471ESA+T-MAX472CSA+-MAX472ESA-T
Precision, High-Side Current-Sense Amplifiers
Not Recommended for New Designs
This product was manufactured for Maxim by an outside wafer foundry
using a process that is no longer available. It is not recommended for
new designs. The data sheet remains available for existing users.
A Maxim replacement or an industry second-source may be available.
Please see the QuickView data sheet for this part or contact technical
support for assistance.
For further information, contact Maxim’s Applications Tech Support.
_______________General Description
The MAX471/MAX472 are complete, bidirectional, high-
side current-sense amplifiers for portable PCs, tele-
phones, and other systems where battery/DC
power-line monitoring is critical. High-side power-line
monitoring is especially useful in battery-powered sys-
tems, since it does not interfere with the ground paths
of the battery chargers or monitors often found in
“smart” batteries.
The MAX471 has an internal 35mΩcurrent-sense resis-
tor and measures battery currents up to ±3A. For appli-
cations requiring higher current or increased flexibility,
the MAX472 functions with external sense and gain-set-
ting resistors. Both devices have a current output that
can be converted to a ground-referred voltage with a
single resistor, allowing a wide range of battery volt-
ages and currents.
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-
ture, and include a 18μA max shutdown mode.
________________________Applications
Portable PCs:
Notebooks/Subnotebooks/Palmtops
Smart Battery Packs
Cellular Phones
Portable Phones
Portable Test/Measurement Systems
Battery-Operated Systems
Energy Management Systems
____________________________FeatureComplete High-Side Current SensingPrecision Internal Sense Resistor (MAX471)2% Accuracy Over TemperatureMonitors Both Charge and Discharge3A Sense Capability with Internal Sense Resistor
(MAX471)Higher Current-Sense Capability with External
Sense Resistor (MAX472)100μA Max Supply Current18μA Max Shutdown Mode3V to 36V Supply Operation8-Pin DIP/SO Packages
______________Ordering Information
Precision, High-Side
Current-Sense Amplifie
OUT
RS-
RS-
SIGNGND
RS+
RS+
SHDN
MAX471
DIP/SO
TOP VIEW
_________________Pin Configurations
MAX471
RS+
RS+RS-
RS-
SIGN
OUTGNDSHDN
3V
TO
36V
100k
ILOAD
ILOAD TO
LOAD or CHARGER
LOGIC
SUPPLY
DISCHARGE/CHARGE
VOUT (1V/A)
__________Typical Operating Circuit
19-0335; Rev 2; 12/96
PART
MAX471CPA
MAX471CSA
MAX471EPA-40°C to +85°C
0°C to +70°C
0°C to +70°C
TEMP. RANGEPIN-PACKAGE
8 Plastic DIP
8 SO
8 Plastic DIP
MAX471ESA-40°C to +85°C8 SO
MAX472CPA0°C to +70°C8 Plastic DIP
MAX472CSA0°C to +70°C8 SO
MAX472EPA-40°C to +85°C8 Plastic DIP
MAX472ESA-40°C to +85°C8 SO
MAX472 Pin Configuration continued on last page.
Precision, High-Side
Current-Sense Amplifiers
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS—MAX471
(RS+ = +3V to +36V, TA= TMINto TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Supply Voltage, RS+, RS-, VCCto GND....................-0.3V, +40V
RMS Current, RS+ to RS- (MAX471 only)..........................±3.3A
Peak Current, (RS+ to RS-)......................................see Figure 5
Differential Input Voltage, RG1 to RG2 (MAX472 only) .....±0.3V
Voltage at Any Pin Except SIGN
MAX471 only...........................................-0.3V to (RS+ - 0.3V)
MAX472 only..........................................-0.3V to (VCC+ 0.3V)
Voltage at SIGN......................................................-0.3V to +40V
Current into SHDN, GND, OUT, RG1, RG2, VCC................±50mA
Current into SIGN.................................................+10mA, -50mA
Continuous Power Dissipation (TA= +70°C)
MAX471 (Note 1):
Plastic DIP (derate 17.5mW/°C above +70°C)..................1.4W
SO (derate 9.9mW/°C above +70°C).............................791mW
MAX472 :
Plastic DIP (derate 9.09mW/°C above +70°C)..............727mW
SO (derate 5.88mW/°C above +70°C)...........................471mW
Operating Temperature Ranges
MAX47_C_A........................................................0°C to +70°C
MAX47_E_A.....................................................-40°C to +85°C
Junction Temperature Range............................-60°C to +150°C
Storage Temperature Range.............................-60°C to +160°C
Lead Temperature (soldering, 10sec).............................+300°C
VSHDN= 2.4V
ILOAD= 0A, excludes ISIGN
VSHDN= 0V
VSHDN= 2.4V; VCC= 3V to 20V
VSIGN= 0.3V
VSIGN = 36V
ILOAD= 30mA,
RS+ = 10V
MAX471E
MAX471C
ILOAD= 0A,
RS+ = 10V
ILOAD= 1A,
RS+ = 10V
3V ≤RS+ ≤36V, ILOAD= 1A
CONDITIONS0VRS+- 1.5VOUTOUT Output Voltage Range1.0IIHSHDN Input High Current2.4VIHSHDN Input High Voltage1.0IILSHDN Input Low Current0.3VILSHDN Input Low Voltage1.518.0IRS+(SHDN)Shutdown Supply Current0.1IOLSIGN Sink Current1.0SIGN Output Leakage Current±4.0±6.0SIGN Threshold (ILOADrequired
to switch SIGN)
%/V0.1PSRRPower-Supply Rejection Ratio
ARMS±3ILOADSense Current113IRS+36VRS+Supply Voltage
Supply Current±3.0Low-Level OUT Error±2.53.0No-Load OUT Error3570RSENSESense Resistor
0.4900.5000.510mA/A0.48750.5000.5125
IOUT/
ILOADCurrent-Sense Ratio
UNITSMINTYPMAXSYMBOLPARAMETER
OUT Output ResistanceROUTILOAD= 3.0A, VOUT= 0V to (VRS+- 1.5V)13MΩ
OUT Rise, Fall TimetR, tFILOAD= 50mA to 3.0A, ROUT= 2kΩ,
COUT= 50pF, 10% to 90%4μs
OUT Settling Time to 1%
of Final ValuetsILOAD= 100mA to 3.0A, ROUT= 2kΩ,
COUT= 50pF15μs
MAX471C
MAX471C
MAX471C
MAX471E
MAX471E
MAX471E
±7.0
Note 1:Due to special packaging considerations, MAX471 (DIP, SO) has a higher power dissipation rating than the MAX472. RS+
andRS- must be soldered to large copper traces to achieve this dissipation rating.
Precision, High-Side
Current-Sense Amplifiers
ELECTRICAL CHARACTERISTICS—MAX472
(VCC= +3V to +36V, RG1 = RG2 = 200Ω, TA= TMINto TMAX, unless otherwise noted. Typical values are at TA = +25°C.)
Note 2:VOSis defined as the input voltage (VSENSE) required to give minimum IOUT.
Note 3:VSENSEis the voltage across the sense resistor.
VSHDN= 2.4V
MAX472C
VSHDN= 0V
ILOAD= 0A, excludes ISIGN; VCC= 3V to 20V
VSHDN= 2.4V; VCC= 3V to 20V
VSIGN= 0.3V
VSIGN= 36V
VCC= 10V,
VSENSE= 3mV
VCC= 10V
MAX472E
IRG1- IGR2
3V ≤VCC≤36V, VSENSE= 100mV
CONDITIONS0VCC- 1.5VOUTOUT Output Voltage Range1.0IIHSHDN Input High Current2.4VIHSHDN Input High Voltage1.0IILSHDN Input Low Current0.3VILSHDN Input Low Voltage1.518.0ICC(SHDN)Shutdown Supply Current0.1SIGN Output Sink Current1.0SIGN Output Leakage Current60140
SIGN Threshold (VSENSE
required to switch SIGN)120
%/V0.1PSRRPower-Supply Rejection Ratio
1202048ICC336VCCSupply Voltage
Supply Current±3.0Low-Level OUT Error±2.52.5140VOSInput Offset Voltage
(Note 2)2035IRG1, IRG2Input Bias Current±0.4±3.0IOSInput Bias-Current Matching
UNITSMINTYPMAXSYMBOLPARAMETER
OUT Output ResistanceROUTIOUT= 1.5mA13MΩ
OUT Rise, Fall TimetR, tFVSENSE= 5mV to 150mV, ROUT= 2kΩ,
COUT= 50pF, 10% to 90%4μs
OUT Settling Time to 1%
of Final ValuetsVSENSE= 5mV to 150mV, ROUT= 2kΩ,
COUT= 50pF15μs
Maximum Output CurrentIOUT1.5mA
MAX472C
MAX472E
MAX472C
MAX472E
VCC= 10V,
VSENSE= 0V3No-Load OUT ErrorMAX472C
MAX472E
VSENSE= 100mV,
VCC= 10V (Note 3)IRG/IOUTOUT Current AccuracyMAX472C%±2
MAX472E±2.5
Precision, High-Side
Current-Sense Amplifiers
__________________________________________Typical Operating Characteristics
(Typical Operating Circuit (MAX471) or circuit of Figure 4, RG1 = RG2 = 200Ω, ROUT= 2kΩ(MAX472), TA= +25°C, unless
otherwise noted.)
SUPPLY CURRENT vs.
SUPPLY VOLTAGE
AX1471-01
VRS+ (V)
(m2415189123627303336TA = +85°C
TA = +25°C
TA = -40°C
AX1471-021.5
SHUTDOWN CURRENT vs.
SUPPLY VOLTAGE
VRS+(V)2415189123627303336
TA = +85°C
TA = -40°C
TA = +25°C
SIGN THRESHOLD vs.
SUPPLY VOLTAGE
AX1471-03
(m2415189123627303336
TA = +85°C
TA = +25°C
TA = -40°C
VRS+ (V)
MAX1471-04
MAX471
NO-LOAD OFFSET CURRENT vs.
SUPPLY VOLTAGE
VRS+ (V)2415189123627303336
VS+ = VS-
TA = -40°C
TA = +85°C
TA = +25°C
TEMPERATURE (°C)
(m
AX1471-07
MAX471
RS+ TO RS- RESISTANCE vs.
TEMPERATURE
MAX471
ERROR vs. LOAD CURRENT
MAX471-05
ILOAD (A)10
ILOAD FROM RS+ TO RS-
ILOAD FROM RS- TO RS+
MAX471
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX471-06
POWER-SUPPLY FREQUENCY (kHz)100
V = 0mV TO 50mV
V = 0V TO 1V
V = 0V TO 0.5V
ILOAD = 1A
RS+
OUT
GND
RS–FV
MAX472
NO-LOAD OUTPUT ERROR vs.
SUPPLY VOLTAGE
MAX1471-08
VCC (V)
(m2415189123627303336
TA = +85°C
TA = -40°C
TA = +25°C
RG1 = RG2 = 0W
AX1471-09
(%
MAX472
ERROR vs. SUPPLY VOLTAGE
VCC (V)2415189123627303336
VRG1-VRG2 = 60mV,
RG1 = RG2 = 200W
TA = -40°C
TA = +25°C
TA = +85°C
Precision, High-Side
Current-Sense Amplifiers
MAX472
ERROR vs. SENSE VOLTAGE
MAX471-10
VSENSE (mV)
VRG1-VRG2
VRG2-VRG1
1mA10mA100mA1A
MAX471
NOISE vs. LOAD CURRENT
ISENSE
MAX471-15
____________________________Typical Operating Characteristics (continued)
(Typical Operating Circuit (MAX471) or circuit of Figure 4, RG1 = RG2 = 200Ω, ROUT= 2kΩ(MAX472), TA= +25°C, unless
otherwise noted.)
100ms/div
VCC = 10V, ROUT = 2kW 1%, SIGN PULL-UP = 50kW 1%
LOAD
CURRENT
50mA/div
VOUT
50mV/div
MAX471
0mA to 100mA TRANSIENT RESPONSE
10ms/div
ILOAD = 1A, ROUT = 2kW 1%
VOUT
500mV/div
MAX471
START-UP DELAY
VSHDN
5V/div
10ms/div
ROUT = 2kW 1%
ILOAD
1A/div
MAX471
0A TO 3A TRANSIENT RESPONSE
VOUT
10mV/div
100ms/div
VCC = 10V, ROUT = 2kW 1%, SIGN PULL-UP = 50kW 1%
LOAD
CURRENT
100mA/div
50mA/div50mA/div
VOUT
50mV/div
MAX471
-100mA to +100mA TRANSIENT RESPONSE
SIGN
50mV/div
_______________Detailed Description
The MAX471 and MAX472 current-sense amplifier’s
unique topology allows a simple design to accurately
monitor current flow. The MAX471/MAX472 contain two
amplifiers operating as shown in Figures 1 and 2. The
battery/load current flows from RS+ to RS- (or vice
versa) through RSENSE. Current flows through either
RG1 and Q1 or RG2 and Q2, depending on the sense-
resistor current direction. Internal circuitry, not shown in
Figures 1 and 2, prevents Q1 and Q2 from turning on at
the same time. The MAX472 is identical to the
MAX471, except that RSENSEand gain-setting resistors
RG1 and RG2 are external (Figure 2).
To analyze the circuit of Figure 1, assume that current
flows from RS+ to RS- and that OUT is connected to
GND through a resistor. In this case, amplifier A1 is
active and output current IOUTflows from the emitter of
Q1. Since no current flows through RG2 (Q2 is off), the
negative input of A1 is equal to VSOURCE- (ILOADx
RSENSE). The open-loop gain of A1 forces its positive
input to essentially the same level as the negative input.
Therefore, the drop across RG1 equals ILOADx
RSENSE. Then, since IOUTflows through Q1 and RG
(ignoring the extremely low base currents), IOUTx RG1
= ILOADx RSENSE, or:
IOUT= (ILOADx RSENSE)/ RG1
Current Output
The output voltage equation for the MAX471/MAX472 is
given below. In the MAX471, the current-gain ratio has
been preset to 500μA/A so that an output resistor
(ROUT) of 2kΩyields 1V/A for a full-scale value of +3V
at ±3A. Other full-scale voltages can be set with differ-
ent ROUTvalues, but the output voltage can be no
greater than VRS+- 1.5V for the MAX471 or VRG_- 1.5V
for the MAX472.
VOUT= (RSENSEx ROUTx ILOAD) / RG
where VOUT= the desired full-scale output voltage,
ILOAD= the full-scale current being sensed, RSENSE=
the current-sense resistor, ROUT= the voltage-setting
resistor, and RG = the gain-setting resistor (RG = RG1
= RG2).
The above equation can be modified to determine the
ROUTrequired for a particular full-scale range:
ROUT= (VOUTx RG) / (ILOADx RSENSE)
For the MAX471, this reduces to:
ROUT= VOUT/ (ILOADx 500μA/A)
OUT is a high-impedance current-source output that
can be connected to other MAX471/MAX472 OUT pins
Precision, High-Side
Current-Sense Amplifiers
______________________________________________________________Pin Description
Load side of the internal current-sense resistor. The “-” indicates direction of flow for SIGN
output only. Connect pins 6 and 7 together at the package.RS-6, 7
Gain Resistor. Connect to load side of current-sense resistor through the gain resistor.RG2—
Power input for MAX472. Connect to sense resistor (RSENSE) junction with RG1.VCC—
Current output that is proportional to the magnitude of the sensed current flowing through
RSENSE. A 2kΩresistor from this pin to ground will result in a voltage equal to 1V/Amp of
sensed current in the MAX471.
OUT8
Gain Resistor. Connect to battery side of current-sense resistor through the gain resistor.RG1—
Ground or Battery Negative TerminalGND4
An open-collector logic output. For the MAX471, a low level indicates current is flowing from
RS- to RS+. For the MAX472, a low level indicates a negative VSENSE(see Figure 2). SIGN is
high impedance when SHDN is high. Leave open if SIGN is not needed.
SIGN5
No Connect—no internal connectionN.C.—
Battery (or power) side of the internal current-sense resistor. The “+” indicates direction of
flow for SIGN output only. Connect pins 2 and 3 together at the package.RS+2, 3
Shutdown. Connect to ground for normal operation. When high, supply current is
less than 5μA. SHDN1
FUNCTION
MAX471
NAME
PIN
MAX472

Partno	Mfg	Dc	Qty	Available	Descript
MAX471CSA+T \|MAX471CSAT	MAXIM	N/a	957	avai	Precision, High-Side Current-Sense Amplifiers
MAX471CSA-T \|MAX471CSAT	MAXIM	N/a	82	avai	Precision, High-Side Current-Sense Amplifiers
MAX471CSA+ \|MAX471CSA	MAXIM	N/a	120	avai	Precision, High-Side Current-Sense Amplifiers
MAX471ESA+T \|MAX471ESAT	MAXIM	N/a	10287	avai	Precision, High-Side Current-Sense Amplifiers
MAX472CSA+	N/A	N/a	2500	avai	Precision, High-Side Current-Sense Amplifiers
MAX472ESA-T \|MAX472ESAT	MAXIN	N/a	1000	avai	Precision, High-Side Current-Sense Amplifiers