LTC6102CDD LINER [Linear Technology], LTC6102CDD Datasheet - Page 14

• Manufacturer Part Number: LTC6102CDD
• Description: Precision Zero Drift Current Sense Amplifi er
• Manufacturer: LINER [Linear Technology]

APPLICATIONS INFORMATION
LTC6102/LTC6102HV
Because the voltage across R
the sense range of the LTC6102 in this circuit, V
can be large compared to the allowed sense voltage. This
facilitates the sensing of very large voltages, provided
that R
the allowed output current. The gain is still controlled by
R
the input signal as it is translated to the output. Finally,
the input may be a voltage source rather than a sense
resistor, as shown in Figure 7. This circuit allows the
translation of a wide variety of input signals across the
entire supply range of the LTC6102 with only a tiny offset
error while retaining simple gain control set by R
14
OUT
Figure 6. LTC6102 Supply Current Monitored with Load
R
V
/R
V
SENSE
CM
IN
IN
IN
V
LOAD
+
is chosen so that V
V
, so either gain or attenuation may be applied to
BAT
V
Figure 7. Voltage Level-Shift Circuit
R
OUT
IN
R
IN
= V
+IN
V
+IN
V
IN
–
–
•
R
LTC6102
LTC6102
R
OUT
IN
+
+
SENSE
–
SENSE
–
/R
IN
is not restricted to
V
OUT
–INS
–INF
V
V
OUT
–INS
–INF
V
REG
+
REG
does not exceed
+
R
R
OUT
OUT
0.1μF
V
0.1μF
V
OUT
6102 F06
OUT
OUT
6102 F07
SENSE
/R
IN
.
Again, very large voltages may be sensed as long as R
is chosen so that I
current. For example, V
1k, or as large as 10V with R
input and a 5V maximum output, R
will allow the LTC6102HV to translate V
common mode voltage of up to 100V. For the case where
a large input resistor is used, a similar resistor in series
with +IN will reduce error due to input bias current.
Reverse Supply Current
Some applications may be tested with reverse-polarity
supplies due to an expectation of this type of fault during
operation. The LTC6102 is not protected internally from
external reversal of supply polarity. To prevent damage
that may occur during this condition, a Schottky diode
should be added in series with V
limit the reverse current through the LTC6102. Note that
this diode will limit the low voltage performance of the
LTC6102 by effectively reducing the supply voltage to the
part by V
In addition, if the output of the LTC6102 is wired to a device
that will effectively short it to high voltage (such as through
an ESD protection clamp) during a reverse supply condi-
tion, the LTC6102’s output should be connected through
a resistor or Schottky diode (Figure 9).
Figure 8. Schottky Prevents Damage During Supply Reversal
O
A
D
L
D
.
+IN
V
D1
–
LTC6102
OUT
+
R
does not exceed the allowed output
SENSE
IN
–
may be as large as 1V with R
IN
= 10k. For a 10V maximum
–INS
V
OUT
–INF
V
+
REG
–
IN
0.1μF
(Figure 8). This will
= 10k and R
R1
100
R2
4.99k
IN
to V
6102 F08
OUT
OUT
V
BATT
with a
= 5k
6102fb
IN
IN
=