19-2562; Rev 1; 11/08
KIT
ATION
EVALU
BLE
AVAILA
76V, High-Side, Current-Sense Amplifiers with
Voltage Output
General Description
The MAX4080/MAX4081 are high-side, current-sense
amplifiers with an input voltage range that extends from
4.5V to 76V making them ideal for telecom, automotive,
backplane, and other systems where high-voltage cur-
rent monitoring is critical. The MAX4080 is designed for
unidirectional current-sense applications and the
MAX4081 allows bidirectional current sensing. The
MAX4081 single output pin continuously monitors the
transition from charge to discharge and avoids the
need for a separate polarity output. The MAX4081
requires an external reference to set the zero-current
output level (V
SENSE
= 0V). The charging current is rep-
resented by an output voltage from V
REF
to V
CC
, while
discharge current is given from V
REF
to GND.
For maximum versatility, the 76V input voltage range
applies independently to both supply voltage (V
CC
)
and common-mode input voltage (V
RS+
). High-side
current monitoring does not interfere with the ground
path of the load being measured, making the
MAX4080/MAX4081 particularly useful in a wide range
of high-voltage systems.
The combination of three gain versions (5V/V, 20V/V,
60V/V = F, T, S suffix) and a user-selectable, external
sense resistor sets the full-scale current reading and its
proportional output voltage. The MAX4080/MAX4081
offer a high level of integration, resulting in a simple,
accurate, and compact current-sense solution.
The MAX4080/MAX4081 operate from a 4.5V to 76V sin-
gle supply and draw only 75µA of supply current. These
devices are specified over the automotive operating
temperature range (-40°C to +125°C) and are available
in a space-saving 8-pin µMAX
®
or SO package.
Features
♦
Wide 4.5V to 76V Input Common-Mode Range
♦
Bidirectional or Unidirectional I
SENSE
♦
Low-Cost, Compact, Current-Sense Solution
♦
Three Gain Versions Available
5V/V (MAX4080F/MAX4081F)
20V/V (MAX4080T/MAX4081T)
60V/V (MAX4080S/MAX4081S)
♦
±0.1% Full-Scale Accuracy
♦
Low 100µV Input Offset Voltage
♦
Independent Operating Supply Voltage
♦
75µA Supply Current (MAX4080)
♦
Reference Input for Bidirectional OUT (MAX4081)
♦
Available in a Space-Saving, 8-Pin
µMAX
Package
MAX4080/MAX4081
Ordering Information
PART
MAX4080FAUA
MAX4080FASA
MAX4080TAUA
MAX4080TASA
MAX4080SAUA
MAX4080SASA
MAX4081FAUA
MAX4081FASA
MAX4081TAUA
MAX4081TASA
MAX4081SAUA
MAX4081SASA
TEMP RANGE
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
PIN-PACKAGE
8 µMAX
8 SO
8 µMAX
8 SO
8 µMAX
8 SO
8 µMAX
8 SO
8 µMAX
8 SO
8 µMAX
8 SO
Applications
Automotive (12V, 24V, or 42V Batteries)
48V Telecom and Backplane Current
Measurement
Bidirectional Motor Control
Power-Management Systems
Avalanche Photodiode and PIN-Diode Current
Monitoring
General System/Board-Level Current Sensing
Precision High-Voltage Current Sources
Selector Guide appears at end of data sheet.
Pin Configurations
TOP VIEW
RS+
V
CC
N.C.
1
2
8
7
RS-
N.C.
N.C.
OUT
RS+ 1
V
CC
N.C.
2
8
7
RS-
REF1A
REF1B
OUT
MAX4080
3
6
5
MAX4081
3
6
5
GND 4
GND 4
µMAX is a registered trademark of Maxim Integrated Products, Inc.
μMAX/SO
μMAX/SO
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
76V, High-Side, Current-Sense Amplifiers with
Voltage Output
MAX4080/MAX4081
ABSOLUTE MAXIMUM RATINGS
V
CC
to GND ............................................................-0.3V to +80V
RS+, RS- to GND....................................................-0.3V to +80V
OUT to GND.............-0.3V to the lesser of +18V or (V
CC
+ 0.3V)
REF1A, REF1B to GND
(MAX4081 Only)....-0.3V to the lesser of +18V or (V
CC
+ 0.3V)
Output Short Circuit to GND.......................................Continuous
Differential Input Voltage (V
RS
+ - V
RS
-) ...............................±80V
Current into Any Pin..........................................................±20mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin µMAX (derate 4.5mW/°C above +70°C) .............362mW
8-Pin SO (derate 5.88mW/°C above +70°C)................471mW
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°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.
DC ELECTRICAL CHARACTERISTICS
(V
CC
= V
RS+
= 4.5V to 76V, V
REF1A
= V
REF1B
= 5V (MAX4081 only), V
SENSE
= (V
RS+
- V
RS-
) = 0V, R
LOAD
= 100kΩ, T
A
= T
MIN
to
T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Notes 1, 2)
PARAMETER
Operating Voltage Range
Common-Mode Range
Supply Current
Leakage Current
Input Bias Current
Full-Scale Sense Voltage (Note 4)
SYMBOL
V
CC
C
MVR
I
CC
I
RS+
, I
RS-
I
RS+
, I
RS-
V
SENSE
CONDITIONS
Inferred from PSRR test
Inferred from CMRR test (Note 3)
V
CC
= V
RS+
= 76V,
no load
V
CC
= V
RS+
= 76V
MAX4080F/MAX4081F
MAX4080T/MAX4081T
MAX4080S/MAX4081S
MAX4080F/MAX4081F
Gain
A
V
MAX4080T/MAX4081T
MAX4080S/MAX4081S
Gain Accuracy
ΔA
V
V
CC
= V
RS+
= 48V
(Note 5)
T
A
= +25°C
T
A
= -40°C to +85°C
T
A
= T
MIN
to T
MAX
Input Offset Voltage
Common-Mode Rejection Ratio
Power-Supply Rejection Ratio
V
OS
CMRR
PSRR
V
CC
= V
RS+
= 48V
(Note 6)
T
A
= +25°C
T
A
= -40°C to +85°C
T
A
= T
MIN
to T
MAX
V
CC
= 48V, V
RS+
= 4.5V to 76V
V
RS+
= 48V, V
CC
= 4.5V to 76V
MAX4080F/MAX4081F,
V
SENSE
= 1000mV
MAX4080T/MAX4081T,
V
SENSE
= 250mV
MAX4080S/MAX4081S,
V
SENSE
= 100mV
0.15
0.27
V
100
100
124
122
±0.1
MAX4080
MAX4081
MIN
4.5
4.5
75
103
0.01
5
±1000
±250
±100
5
20
60
±0.1
±0.6
±1
±1.2
±0.6
±1
±1.2
dB
dB
mV
%
V/V
mV
TYP
MAX
76
76
190
190
2
12
UNITS
V
V
µA
µA
µA
V
CC
= 0V, V
RS+
= 76V
OUT High Voltage
(V
CC
-
V
OH
)
V
CC
= 4.5V, V
RS+
= 48V, V
REF1A
=
V
REF1B
= 2.5V,
I
OUT
(sourcing) =
+500µA (Note 8)
2
_______________________________________________________________________________________
76V, High-Side, Current-Sense Amplifiers with
Voltage Output
DC ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= V
RS+
= 4.5V to 76V, V
REF1A
= V
REF1B
= 5V (MAX4081 only), V
SENSE
= (V
RS+
- V
RS-
) = 0V, R
LOAD
= 100kΩ, T
A
= T
MIN
to
T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
V
CC
= V
RS+
= 48V,
V
REF1A
= V
REF1B
= I
OUT
(sinking) = 10µA
2.5V, V
SENSE
=
I
OUT
(sinking) =
-1000mV (for
100µA
MAX4081 only)
Inferred from REF1A rejection ratio,
V
REF1A
= V
REF1B
Inferred from REF1A rejection ratio,
V
REF1B
= GND
V
CC
= V
RS+
= 48V, V
SENSE
= 0V,
V
REF1A
= V
REF1B
= 1.5V to 6V
V
REF1A
= 10V, V
REF1B
= GND,
V
CC
= V
RS+
= 48V (Note 2)
V
REF1B
= GND
1.5
3
80
0.497
108
0.500
250
0.503
kΩ
MIN
TYP
4
MAX
15
mV
23
55
6
12
V
V
dB
UNITS
MAX4080/MAX4081
OUT Low Voltage
V
OL
REF1A = REF1B Input Voltage
Range (MAX4081 Only)
REF1A Input Voltage Range
(MAX4081 Only)
REF1A Rejection Ratio
(MAX4081 Only)
REF/REF1A Ratio
(MAX4081 Only)
REF1A Input Impedance
(MAX4081 Only)
(V
REF
-
GND)
(V
REF1A
-
GND)
_______________________________________________________________________________________
3
76V, High-Side, Current-Sense Amplifiers with
Voltage Output
MAX4080/MAX4081
AC ELECTRICAL CHARACTERISTICS
(V
CC
= V
RS+
= 4.5V to 76V, V
REF1A
= V
REF1B
= 5V (MAX4081 only), V
SENSE
= (V
RS+
- V
RS-
) = 0V, R
LOAD
= 100kΩ, C
LOAD
= 20pF,
T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Notes 1, 2)
PARAMETER
Bandwidth
OUT Settling Time to 1% of Final
Value
Capacitive-Load Stability
Output Resistance
Power-Up Time
Saturation Recovery Time
R
OUT
SYMBOL
BW
CONDITION
V
CC
= V
RS+
=
48V, V
OUT
= 2.5V
MAX4080F/T/S
MAX4081F/T/S
MIN
TYP
250
150
20
20
500
0.1
50
50
MAX
UNITS
kHz
µs
pF
Ω
µs
µs
V
SENSE
= 10mV to 100mV
V
SENSE
= 100mV to 10mV
No sustained oscillations
V
SENSE
= 100mV
V
CC
= V
RS+
= 48V, V
SENSE
= 100mV (Note 9)
(Notes 9,10)
Note 1:
All devices are 100% production tested at T
A
= +25°C. All temperature limits are guaranteed by design.
Note 2:
V
REF
is defined as the average voltage of V
REF1A
and V
REF1B
. REF1B is usually connected to REF1A or GND.
V
SENSE
is defined as V
RS+
- V
RS-
.
Note 3:
The common-mode range at the low end of 4.5V applies to the most positive potential at RS+ or RS-. Depending on the
polarity of V
SENSE
and the device’s gain, either RS+ or RS- can extend below 4.5V by the device’s typical full-scale value of
V
SENSE
.
Note 4:
Negative V
SENSE
applies to MAX4081 only.
Note 5:
V
SENSE
is:
MAX4080F, 10mV to 1000mV
MAX4080T, 10mV to 250mV
MAX4080S, 10mV to 100mV
MAX4081F, -500mV to +500mV
MAX4081T, -125mV to +125mV
MAX4081S, -50mV to +50mV
Note 6:
V
OS
is extrapolated from the gain accuracy test for the MAX4080 and measured as (V
OUT
- V
REF
)/A
V
at V
SENSE
= 0V, for the
MAX4081.
Note 7:
V
SENSE
is:
MAX4080F, 500mV
MAX4080T, 125mV
MAX4080S, 50mV
MAX4081F/T/S, 0V
V
REF1B
= V
REF1A
= 2.5V
Note 8:
Output voltage is internally clamped not to exceed 18V.
Note 9:
Output settles to within 1% of final value.
Note 10:
The device will not experience phase reversal when overdriven.
4
_______________________________________________________________________________________
76V, High-Side, Current-Sense Amplifiers with
Voltage Output
Typical Operating Characteristics
(V
CC
= V
RS+
= 48V, V
SENSE
= 0V, C
LOAD
= 20pF, R
LOAD
=
∞,
T
A
= +25°C, unless otherwise noted.)
INPUT OFFSET VOLTAGE
INPUT OFFSET VOLTAGE HISTOGRAM
vs. TEMPERATURE
GAIN ACCURACY vs. TEMPERATURE
MAX4080 toc01
MAX4080 toc02
MAX4080/MAX4081
30
PERCENTAGE (%)
25
20
15
10
5
0
-125 -100 -75 -50 -25 0 25 50 75 100 125
INPUT OFFSET VOLTAGE (μV)
INPUT OFFSET VOLTAGE (μV)
GAIN ACCURACY (%)
250
200
150
100
50
0
-50
-100
-150
-200
-250
-300
-50 -25
0.4
0.3
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
-0.5
0
75 100 125 150
TEMPERATURE (°C)
25
50
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
GAIN ACCURACY vs. V
CC
MAX4080 toc04
MAX4081F/T/S
COMMON-MODE REJECTION RATIO
vs. FREQUENCY
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
-130
1
10
100
1k
10k
100k
FREQUENCY (Hz)
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
-130
1
COMMON-MODE REJECTION RATIO (dB)
MAX4080 toc05
MAX4081F/T/S
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
POWER-SUPPLY REJECTION RATIO (dB)
MAX4080 toc06
0
V
RS+
= 48V
S VERSION
GAIN ACCURACY (%)
-0.05
-0.10
T VERSION
-0.15
F VERSION
-0.20
4
16
28
40
V
CC
(V)
52
64
76
1M
10
100
1k
10k
100k
1M
FREQUENCY (Hz)
MAX4081F/T/S
REFERENCE REJECTION RATIO
vs. FREQUENCY
MAX4080 toc07
MAX4080F/T/S
SMALL-SIGNAL GAIN vs. FREQUENCY
MAX4080 toc08
MAX4081F/T/S
SMALL-SIGNAL GAIN vs. FREQUENCY
45
40
35
GAIN (dB)
30
25
20
15
10
5
0
MAX4081F
V
OUT
= 100mV
P-P
MAX4081S
MAX4080 toc09
0
-10
REFERENCE REJECTION RATIO (dB)
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
1
10
100
1k
10k
50
45
40
35
GAIN (dB)
30
25
20
15
10
5
0
MAX4080F
V
SENSE
= 10mV
MAX4080S
50
MAX4080T
MAX4081T
100k
0.1
1
10
FREQUENCY (kHz)
100
1000
0.1
1
10
FREQUENCY (kHz)
100
1000
FREQUENCY (Hz)
_______________________________________________________________________________________
MAX4080 toc03
35
300
0.5
5
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