lt6109-1 Linear Technology Corporation, lt6109-1 Datasheet - Page 12
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lt6109-1
Manufacturer Part Number
lt6109-1
Description
High Side Current Sense Amplifer With Reference And Comparators
Manufacturer
Linear Technology Corporation
Datasheet
1.LT6109-1.pdf
(28 pages)
APPLICATIONS INFORMATION
LT6109-1/LT6109-2
Selection of External Input Resistor, R
R
resolution while limiting the output current to 1mA. The
maximum value for R
bility. For a given V
power dissipation in the LT6109 due to the reduction
in I
response time due to the increase in I
currents must be resolved accurately in a system that has
a very wide dynamic range, a smaller R
if the maximum I
such as with a Schottky diode across R
This will reduce the high current measurement accuracy
by limiting the result, while increasing the low current
measurement resolution.
This approach can be helpful in cases where occasional
bursts of high currents can be ignored.
12
IN
OUT
should be chosen to allow the required speed and
while smaller values of R
UNDERCURRENT
OVERCURRENT
OUTA
SENSE
IN
FLAG
FLAG
current is limited in another way,
R
SENSE
is 1k to maintain good loop sta-
, larger values of R
V
V
PULLUP
LOAD
SUPPLY
I
R
SENSE
+
–
V
C
C
SENSE
LC
=
V
R
IN
RESET
R
V
C
C
SENSE
SENSE
R
LC
IN
will result in faster
OUT
IN
SENSE
IN
1
2
3
4
5
*R
Figure 3. LT6109-1 Typical Connection
. If low sense
V
SENSELO
EN/RST
OUTC2
OUTC1
may be used
OUT
–
IN
(Figure 4).
= R1 + R2 + R3
will lower
V
–
+
–
V
V
V
V
LT6109-1
+
–
+
–
Figure 4. Shunt Diode Limits Maximum Input Voltage to Allow
Better Low Input Resolution Without Overranging
Care should be taken when designing the board layout for
R
connect resistances will increase the effective R
causing a gain error.
The power dissipated in the sense resistor can cause a
significant thermal gradient and consequently a gain error
if R
different temperatures. If significant power is being dis-
sipated in the sense resistor then care should be taken
V
IN
+
+
+
–
–
, especially for small R
IN
and R
I
OUTA
REFERENCE
400mV
OUT
are placed such that they can operate at
R
SENSEHI
SENSE
OUTA
INC2
INC1
V
V
V
LOAD
+
–
+
V
+
10
9
8
7
6
610912 F04
IN
R3*
R2*
R1*
values. All trace and inter-
610912 F03
C1
D
SENSE
C
L
V
OUT
IN
value,
610912f