Datasheet

76V, High-Side, Current-Sense Amplifiers with
Voltage Output
Table 1. Typical Component Values
FULL-SCALE LOAD
CURRENT, I
LOAD
(A)
CURRENT-SENSE
RESISTOR (mΩ)
GAIN
(V/V)
FULL-SCALE
V
SENSE
(mV)
MAX4081 FULL-SCALE
OUTPUT VOLTAGE
(V
OUT
- V
REF,
V)
0.500 1000 5 ±500 ±2.5
0.125 1000 20 ±125 ±2.5
0.050 1000 60 ±50 ±3.0
5.000 100 5 ±500 ±2.5
1.250 100 20 ±125 ±2.5
0.500 100 60 ±50 ±3.0
50.000 10 5 ±500 ±2.5
12.500 10 20 ±125 ±2.5
5.000 10 60 ±50 ±3.0
FULL-SCALE LOAD
CURRENT, I
LOAD
(A)
CURRENT-SENSE
RESISTOR (mΩ)
GAIN
(V/V)
FULL-SCALE
V
SENSE
(mV)
MAX4080 FULL-SCALE
OUTPUT VOLTAGE (V)
1.000 1000 5 1000 5.0
0.250 1000 20 250 5.0
0.100 1000 60 100 6.0
10.000 100 5 1000 5.0
2.500 100 20 250 5.0
1.000 100 60 100 6.0
50.000 10 5 500 2.5
25.000 10 20 250 5.0
10.000 10 60 100 6.0
External References (MAX4081)
For the bidirectional MAX4081, the V
OUT
reference level
is controlled by REF1A and REF1B. V
REF
is defined as
the average voltage of V
REF1A
and V
REF1B
. Connect
REF1A and REF1B to a low-noise, regulated voltage
source to set the output reference level. In this mode,
V
OUT
equals V
REF1A
when V
SENSE
equals zero (see
Figure 4).
Alternatively, connect REF1B to ground, and REF1A to a
low-noise, regulated voltage source. In this case, the out-
put reference level (V
REF
) is equal to V
REF1A
divided by
two. V
OUT
equals V
REF1A
/2 when V
SENSE
equals zero.
In either mode, the output swings above the reference
voltage for positive current-sensing (V
RS+
> V
RS-
). The
output swings below the reference voltage for negative
current-sensing (V
RS+
< V
RS-
).
Applications Information
Recommended Component Values
Ideally, the maximum load current develops the full-
scale sense voltage across the current-sense resistor.
Choose the gain needed to yield the maximum output
voltage required for the application:
V
OUT
= V
SENSE
 A
V
where V
SENSE
is the full-scale sense voltage, 1000mV
for gain of 5V/V, 250mV for gain of 20V/V, 100mV for
gain of 60V/V, and A
V
is the gain of the device.
In applications monitoring a high current, ensure that
R
SENSE
is able to dissipate its own I
2
R loss. If the resis-
tor’s power dissipation is exceeded, its value may drift
or it may fail altogether.
The MAX4080/MAX4081 sense a wide variety of cur-
rents with different sense-resistor values. Table 1 lists
common resistor values for typical operation.
MAX4080/MAX4081
Maxim Integrated
11