lt6107mps5-trpbf Linear Technology Corporation, lt6107mps5-trpbf Datasheet - Page 10

• Manufacturer Part Number: lt6107mps5-trpbf
• Description: High Temperature High Side Current Sense Amp In Sot-23
• Manufacturer: Linear Technology Corporation

APPLICATIONS INFORMATION
LT6107
power dissipation is 41mW. This amount of power dis-
sipation will result in a 10°C rise in junction temperature
above the ambient temperature.
It is important to note that the LT6107 has been designed
to provide at least 1mA to the output when required, and
can deliver more depending on the conditions. Care must
be taken to limit the maximum output current by proper
choice of sense resistor and R
ditions exist, external clamps.
Output Filtering
The output voltage, V
makes fi ltering straightforward. Any circuit may be used
which generates the required Z
response. For example, a capacitor in parallel with R
will give a lowpass response. This will reduce unwanted
noise from the output, and may also be useful as a charge
reservoir to keep the output steady while driving a switch-
ing circuit such as a MUX or ADC. This output capacitor
in parallel with an output resistor will create a pole in the
output response at:
Useful Equations
Power Supply Connection
For normal operation, the V
either side of the sense resistor. Either connection will
meet the constraint that +IN ≤ V
10
Input Voltage: V
Current Gain:
f
Voltage
Transcond
Transimpedance:
–
3
dB
=
2
G G ain:
• •
u u ctance:
π
I
R
V
SENSE
I
SENSE
OUT
OUT
V
SENSE
1
OUT
I
SENSE
V
OUT
•
O
V
C
=
U U T
I
SENSE
= I
OUT
, is simply I
=
OUT
R
+
SENSE
R
SENSE
R
=
pin should be connected to
R
OUT
OUT
IN
IN
IN
R
=
–
SENSE
+
R
and, if input fault con-
to get the desired fi lter
•
and –IN ≤ V
1
IN
R
SENSE
OUT
•
R
R
OUT
IN
• Z
OUT
+
. During
. This
OUT
normal operation, V
V
ditional constraint can be stated as V
Referring to Figure 5, feedback will force the voltages
at the inputs –IN and +IN to be equal to (V
Connecting V
voltages at +IN, –IN and V
end of the shunt results in the voltages at +IN and –IN to
be V
If the V
resistor, the supply current drawn by the LT6107 is not
included in the monitored current. If the V
nected to the load side of the shunt resistor (Figure 5),
the supply current drawn by the LT6107 is included in
the monitored current. It should be noted that in either
confi guration, the output current of the LT6107 will not
be monitored since it is drawn through the R
connected to the positive side of the shunt. Contact the
factory for operation of the LT6107 with a V
the recommended operating range.
Reverse Supply Protection
Some applications may be tested with reverse-polarity
supplies due to an expectation of the type of fault during
operation. The LT6107 is not protected internally from ex-
ternal reversal of supply polarity. To prevent damage that
may occur during this condition, a Schottky diode should
be added in series with V
reverse current through the LT6107. Note that this diode
will limit the low voltage performance of the LT6107 by ef-
fectively reducing the supply voltage to the part by V
SENSE(MAX)
Figure 5. LT6107 Supply Current Monitored with the Load
SENSE
R
SENSE
+
LOAD
pin is connected to the supply side of the shunt
V
S
below V
+
under Electrical Characteristics). This ad-
R
to the load side of the shunt results in equal
IN
+IN
V
–
+
.
SENSE
LT6107
+
should not exceed 500mV (see
–
+
. Connecting V
(Figure 6). This will limit the
–
–IN
OUT
V
+
6107 F05
+
– (+IN) ≤ 500mV.
R
OUT
V
+
OUT
to the supply
+
S
+
pin is con-
– V
IN
outside of
resistor
SENSE
6107fb
D
.
).