MAX4172 Fast Delivery |IC PHOENIX CO.,LIMITED

MAX4172 ,Low-Cost, Precision, High-Side Current-Sense AmplifierApplications3V TO 32VLOW-COST 0 TO 32V2ASWITCHING● Portable PCs: Notebooks/Subnotebooks/PalmtopsV A ..
MAX4172ESA ,Low-Cost / Precision / High-Side Current-Sense AmplifierApplications__________Typical Operating CircuitPortable PCs: Notebooks/Subnotebooks/PalmtopsBattery ..
MAX4172ESA ,Low-Cost / Precision / High-Side Current-Sense AmplifierApplications__________Typical Operating CircuitPortable PCs: Notebooks/Subnotebooks/PalmtopsBattery ..
MAX4172ESA ,Low-Cost / Precision / High-Side Current-Sense AmplifierFeaturesThe MAX4172 is a low-cost, precision, high-side current-' Low-Cost, High-Side Current-Sense ..
MAX4172ESA ,Low-Cost / Precision / High-Side Current-Sense AmplifierELECTRICAL CHARACTERISTICS(V+ = +3V to +32V; RS+, RS- = 0V to 32V; T = T to T ; unless otherwise no ..
MAX4172ESA. ,Low-Cost / Precision / High-Side Current-Sense AmplifierMAX417219-1184; Rev 0; 12/96Low-Cost, Precision, High-SideCurrent-Sense Amplifier_______________
MAX802TCPA ,3.0V or 3.3V microprocessor supervisory circuit. Reset threshold 3.075V. Active-low reset. Watchdog input. Backup-battery switch. Power-fail threshold accuracy +-2%. Power-fail comparator. Reset window +-2%ELECTRICAL CHARACTERISTICS(V = 3.17V to 5.5V for the MAX690T/MAX704T/MAX80_T, V = 3.02V to 5.5V for ..
MAX802TEPA ,3.0V or 3.3V microprocessor supervisory circuit. Reset threshold 3.075V. Active-low reset. Watchdog input. Backup-battery switch. Power-fail threshold accuracy +-2%. Power-fail comparator. Reset window +-2%ELECTRICAL CHARACTERISTICS(V = 3.17V to 5.5V for the MAX690T/MAX704T/MAX80_T, V = 3.02V to 5.5V for ..
MAX802TESA ,3.0V or 3.3V microprocessor supervisory circuit. Reset threshold 3.075V. Active-low reset. Watchdog input. Backup-battery switch. Power-fail threshold accuracy +-2%. Power-fail comparator. Reset window +-2%Features– — — — — –These microprocessor (µP) supervisory circuits reduce' RESET and RESET Outputsth ..
MAX803LEXR ,3-Pin Microprocessor Reset CircuitsGeneral Description Beneits and
MAX803LEXR+ ,3-Pin Microprocessor Reset CircuitsApplications● ComputersGND GND● Controllers● Intelligent Instruments*MAX803 ONLY● Critical μP and μ ..
MAX803LEXR+T ,3-Pin Microprocessor Reset CircuitsElectrical Characteristics(V = full range, T = -40°C to +105°C (SOT23) or T = -40°C to +125°C (SC70 ..

MAX4172
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 critical.
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 device suitable for
closed-loop battery-charger and general-purpose current-
source applications. The 0 to 32V input common-mode
range is independent of the supply voltage, which ensures
that current-sense feedback remains viable, even when
connected to a battery in deep discharge.
To provide a high level of flexibility, the MAX4172 functions
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 single
resistor, accommodating a wide range of battery voltages
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
amplifier. 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
Beneits and Features●Ideal for High-Side Monitoring3V to 32V Supply Operation±0.5% Typical Full-Scale Accuracy Over TemperatureHigh Accuracy +2V to +32V Common-Mode
Range, Functional Down to 0V, Independent of
Supply Voltage800kHz Bandwidth [VSENSE = 100mV (1C)]200kHz Bandwidth [VSENSE = 6.25mV (C/16)]●Minimizes Board Space RequirementsμMAX and SO Packages
μMAX is a registered trademark of Maxim Integrated Products, Inc.
+Denotes a lead(Pb)-free/RoHS-compliant package.
PARTTEMP RANGEPIN-PACKAGE
MAX4172ESA+-40°C to +85°C8 SO
MAX4172EUA+-40°C to +85°C8 μMAX
MAX4172GUA+-40°C to +105°C8 µMAX
OUT
GND
FEEDBACK LOOP
LOW-COST BATTERY CHARGER/CURRENT SOURCE
VOUT = 500mV/A
ROUT
1kΩ
100kΩ
ANALOG OR
LOGIC SUPPLY0 TO 32V
IOUT =
VSENSE / 100Ω
RS+
RSENSE
50mΩ
VSENSE
RS-
MAX4172POWER GOODLOAD/
BATTERY
LOW-COST
SWITCHING
REGULATOR
UNREGULATED
DC SUPPLY
3V TO 32V
TOP VIEW
OUT
GNDN.C.RS-
N.C.
RS+
µMAX/SO
MAX4172
MAX4172Low-Cost, Precision, High-Side
Current-Sense Amplifier
Typical Operating Circuit
Pin Coniguration
Ordering Information
V+, RS+, RS-, PG .................................................-0.3V to +36V
OUT .............................................................-0.3V to (V+ + 0.3V)
Differential Input Voltage, VRS+ - VRS- ..........................±700mV
Current into Any Pin .........................................................±50mA
Continuous Power Dissipation (TA = +70°C)
SO (derate 5.88mW/°C above +70°C) ........................471mW μMAX (derate 4.10mW/°C above +70°C) ...................330mW
Operating Temperature Range
MAX4172E_A .................................................-40°C to +85°C
MAX4172G_A ...............................................-40°C to +105°C
Storage Temperature Range ............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°C
(V+ = +3V to +32V; VRS+, VRS- = 0 to 32V; TA = TMIN to TMAX; unless otherwise noted. Typical values are at V+ = +12V,
VRS+ = 12V, TA = +25°C.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
Operating Voltage RangeV+332V
Input Voltage RangeVRS-0032V
Supply CurrentIV+IOUT = 0mA0.81.6mA
Input Offset VoltageVOSV+ = 12V, VRS+ = 12VMAX4172ESA±0.1±0.75MAX4172EUA±0.2±1.6
VRS+ ≤ 2.0V4
Positive Input Bias CurrentIRS+VRS+ > 2.0V, IOUT = 0mA02742.5µAVRS+ ≤ 2.0V, IOUT = 0mA-325+42.5
Negative Input Bias
CurrentIRS-VRS+ > 2.0V05085µAVRS+ ≤ 2.0V-65085
Maximum VSENSE Voltage150175mV
Low-Level Current ErrorVSENSE = 6.25mV, V+ = 12V,
VRS+ = 12V (Note 1)
MAX4172ESA±8.0µAMAX4172EUA±15
Output Current ErrorVSENSE = 100mV, V+ = 12V,
VRS+ = 12V
MAX4172ESA,
TA = -40°C to 0°C±20
MAX4172EUA,
TA = -40°C to 0°C±50
MAX4172ESA,
TA = 0°C to +105°C±10
MAX4172EUA,
TA = 0°C to +105°C±15
OUT Power-Supply
Rejection RatioΔIOUT/ΔV+3V ≤ V+ ≤ 32V, VRS+ > 2.0V0.2μA/V
OUT Common-Mode
Rejection RatioΔIOUT/ΔVRS+2.0V < VRS+ < 32V0.03μA/V
MAX4172Low-Cost, Precision, High-SideCurrent-Sense Ampliier
Absolute Maximum Ratings
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.
Electrical Characteristics
(V+ = +3V to +32V; VRS+, VRS- = 0 to 32V; TA = TMIN to TMAX; unless otherwise noted. Typical values are at V+ = +12V,
VRS+ = 12V, TA = +25°C.)
Note 1: 6.25mV = 1/16 of typical full-scale sense voltage (C/16).
Note 2: Valid operation of the MAX4172 is guaranteed by design when PG is low.
(V+ = +12V, VRS+ = 12V, ROUT = 1kΩ, TA = +25°C, unless otherwise noted.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
Maximum Output Voltage
(OUT)IOUT ≤ 1.5mAV+ - 1.2V
BandwidthVSENSE = 100mV800kHzVSENSE = 6.25mV (Note 1)200
Maximum Output CurrentIOUT1.51.75mA
TransconductanceGmGm = IOUT/(VRS+ - VRS-),
VSENSE = 100mV, VRS+ > 2.0V
TA = 0°C to +105°C9.81010.2mA/VTA = -40°C to 0°C9.71010.3
V+ Threshold for PG
Output Low (Note 2)
V+ rising2.77VV+ falling2.67
PG Output Low VoltageVOLISINK = 1.2mA, V+ = 2.9V, TA = +25°C0.4V
Leakage Current into PGV+ = 2.5V, TA = +25°C1µA
Power-Off Input Leakage
Current (RS+, RS-)V+ = 0V, VRS+ = VRS- = 32V0.11µA
OUT Rise TimeVSENSE = 0 to 100mV, 10% to 90%400ns
OUT Fall TimeVSENSE = 100mV to 0mV, 90% to 10%800ns
OUT Settling Time to 1%VSENSE = 5mV to 100mVRising1.3µsFalling6
OUT Output ResistanceVSENSE = 150mV20MΩ
OUTPUT ERROR
vs. SUPPLY VOLTAGE
MAX4172-02
ERROR (%)30
VSENSE = 100mV
TA = -40°C
TA = +105°C
TA = +85°C
TA = +25°C10
C/16 LOAD OUTPUT ERROR
vs. SUPPLY VOLTAGE
MAX4172-03
ERROR (%)30
TA = +25°C
VSENSE = 6.25mV
TA = -40°C
TA = +85°C
TA = +105°CIOUT = 0mA
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX4172-01
QUIESCENT SUPPLY CURRENT (μA)30
IOUT = 0mA
TA = +105°C
TA = +85°C
TA = +25°C
TA = -40°C
MAX4172Low-Cost, Precision, High-SideCurrent-Sense Ampliier
Electrical Characteristics (continued)
Typical Operating Characteristics
(V+ = +12V, VRS+ = 12V, ROUT = 1kΩ, TA = +25°C, unless otherwise noted.)
0.1m10m100m1m1
ERROR vs. SENSE VOLTAGE
MAX4172-04
VSENSE (V)
ERROR (%)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX4172-05
POWER-SUPPLY FREQUENCY (kHz)
ERROR (%)15
5mVP-P
1.0VP-P
0.5VP-P
VSENSE = 100mV
OUTPUT ERROR
vs. COMMON MODE VOLTAGE
MAX4172-06
V+ (V)
OUTPUT ERROR (%)1620
VSENSE = 100mV
TA = +25°C
TA = +105°C
TA = -40°C
TA = +85°C
V+ THRESHOLD FOR PG OUTPUT LOW
vs. TEMPERATURE
MAX4172-07
TEMPERATURE (°C)
V+ TRIP THRESHOLD (V)5075100
10µs/div
0 to 10mV VSENSE TRANSIENT RESPONSE
GND
VSENSE
5mV/div
VOUT
50mV/div
GND
MAX4172-08
10µs/div
0 to 100mV VSENSE TRANSIENT RESPONSE
GND
VSENSE
50mV/div
VOUT
500mV/div
GND
MAX4172-09
MAX4172Low-Cost, Precision, High-Side Current-Sense Ampliier
Typical Operating Characteristics (continued)
(V+ = +12V, VRS+ = 12V, ROUT = 1kΩ, TA = +25°C, unless otherwise noted.)
Detailed Description
The MAX4172 is a unidirectional, high-side current-
sense amplifier with an input common-mode range that is
independent of supply voltage. This feature not only
allows the monitoring of current flow into a battery in deep
discharge, but also enables high-side current sensing at
voltages far in excess of the supply voltage (V+).
The MAX4172 current-sense amplifier’s unique topology
simplifies current monitoring and control. The MAX4172’s
amplifier operates as shown in Figure 1. The battery/
load current flows through the external sense resistor
(RSENSE), from the RS+ node to the RSnode. Current
flows through RG1 and Q1, and into the current mirror,
where it is multiplied by a factor of 50 before appearing
at OUT.
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. Since A1’s inverting input is high
impedance, no current flows though RG2 (neglecting the
input bias current), so A1’s negative input is equal to
VSOURCE - (ILOAD x RSENSE). A1’s open-loop gain forces
its positive input to essentially the same voltage level as
the negative input. Therefore, the drop across RG1 equals
PINNAMEFUNCTIONRS+Power connection to the external sense resistor. The “+” indicates the direction of current low.RS-Load-side connection for the external sense resistor. The “-” indicates the direction of current low.
3, 4N.C.No Connect. No internal connection. Leave open or connect to GND.GNDGroundOUTCurrent Output. OUT is proportional to the magnitude of the sense voltage (VRS+ - VRS-). A 1kΩ
resistor from OUT to ground will result in a voltage equal to 10V/V of sense voltage.PGPower Good Open-Collector Logic Output. A low level indicates that V+ is suficient to power the
MAX4172, and adequate time has passed for power-on transients to settle out.V+Supply Voltage Input for the MAX4172
5µs/div
STARTUP DELAY
GND
VOUT
500mV/div
2V/div
GND
VSENSE = 100mV
MAX4172-10
10ms/div
V+ to PG POWER-UP DELAY
GND
2V/div
2V/div
GND
100kW PULLUP RESISTOR FROM PG TO +4V
MAX4172-11
MAX4172Low-Cost, Precision, High-SideCurrent-Sense Ampliier
Pin Description
Typical Operating Characteristics (continued)
ILOAD x RSENSE. Then, since IRG1 flows through RG1,
IRG1 x RG1 = ILOAD x RSENSE. The internal current mirror
multiplies IRG1 by a factor of 50 to give IOUT = 50 x IRG1.
Substituting IOUT/50 for IRG1, (IOUT/50) x RG1 = ILOAD
x RSENSE, or:
IOUT = 50 x ILOAD x (RSENSE/RG1)
The internal current gain of 50 and the factory-trimmed
resistor RG1 combine to result in the device’s transcon-
ductance (Gm) of 10mA/V. Gm is defined as being equal
to IOUT/(VRS+ - VRS-). Since (VRS+ - VRS-) = ILOAD x
RSENSE, the output current (IOUT) can be calculated with
the following formula:
IOUT = Gm x (VRS+ - VRS-) =
(10mA/V) x (ILOAD x RSENSE)
Current Output
The output voltage equation for the MAX4172 is given
below:
VOUT = (Gm) x (RSENSE x ROUT x ILOAD)
where VOUT = the desired full-scale output voltage, ILOAD
equals the full-scale current being sensed, RSENSE
equals the current-sense resistor, ROUT equals the
voltage-setting resistor, and Gm equals the device’s
transconductance (10mA/V).
The full-scale output voltage range can be set by changing
the ROUT resistor value, but the output voltage must be
no greater than V+ - 1.2V. The above equation can be
modified to determine the ROUT required for a particular
full-scale range:
ROUT = (VOUT)/(ILOAD x RSENSE x Gm)
OUT is a high-impedance current source that can be
integrated by connecting it to a capacitive load.
PG Output
The PG output is an open-collector logic output that
indicates the status of the MAX4172’s V+ power supply. A
logic low on the PG output indicates that V+ is sufficient to
power the MAX4172. This level is temperature dependent
(see Typical Operating Characteristics graphs), and is
typically 2.7V at room temperature. The internal PG
comparator has a 100mV (typ) hysteresis to prevent
possible oscillations caused by repeated toggling of the
PG output, making the device ideal for power-management
systems lacking soft-start capability. An internal delay (15μs, typ) in the PG comparator allows adequate time
for power-on transients to settle out. The PG status
indicator greatly simplifies the design of closed-loop
systems by ensuring that the components in the control
loop have sufficient voltage to operate correctly.
Applications Information
Suggested Component Values for Various Applications
The Typical Operating Circuit is useful in a wide variety of
applications. Table 1 shows suggested component values
and indicates the resulting scale factors for various applications
required to sense currents from 100mA to 10A.
Adjust the RSENSE value to monitor higher/lower current
levels. Select RSENSE using the guidelines and formulas
in the following section.
Figure 1. Functional Diagram
RG1
RS+
RSENSE
INPUT
RG2
TO LOAD/
BATTERY
RS-VSENSE
1:50
CURRENT
MIRROR
MAX4172
OUT
VTH
IOUT = 50 IRG1
IRG1
GND
ILOAD
MAX4172Low-Cost, Precision, High-SideCurrent-Sense Ampliier

Partno	Mfg	Dc	Qty	Available	Descript
MAX4172		N/a	12	avai	Low-Cost, Precision, High-Side Current-Sense Amplifier