Datasheet

LT6100
12
6100fc
applicaTions inForMaTion
Low Sense Voltage Operation
Figure 4 shows the simplest circuit configuration in which
the LT6100 may be used. While V
OUT
(output voltage)
increases with positive sense current, at V
SENSE
= 0V,
the LT6100’s buffered output can only swing as low as
V
OL
= 15mV. The accuracy at small sense voltages can be
improved by selecting higher gain. When gain of 50V/V
is selected, as shown in Figure 7, V
OUT
leaves the clipped
region for a positive V
SENSE
greater than 1mV compared
to 2.5mV for gain of 10V/V (see Figure 6).
OUTPUT
V
EE
OUT
6100 F04
R
SENSE
LT6100
81
V
S
–
V
S
+
A4
2
V
CC
A2
3
4
7
C2
0.1µF
C1
0.1µF
3V
6
5
FIL
TO LOAD
+
5V
+
–
+
SENSE VOLTAGE (V
S
+
– V
S
–
) (mV)
0
OUTPUT VOLTAGE (V)
0.6
0.8
1.0
90
150
6100 F05
0.4
0.2
0
30 60 120
1.2
1.4
1.6
V
S
= 4.4V TO 48V
V
CC
= 3V
A
V
= 10V/V
T
A
= 25°C
Figure 4. LT6100 Load Current Monitor Figure 5. Output Voltage vs V
SENSE
SENSE VOLTAGE (V
S
+
– V
S
–
) (mV)
0
OUTPUT VOLTAGE (V)
0.15
0.20
0.25
15
25
6100 F06
0.10
0.05
0
5 10 20
0.30
0.35
0.40
30
V
S
= 4.4V TO 48V
V
CC
= 3V
A
V
= 10V/V
T
A
= 25°C
SENSE VOLTAGE (V
S
+
– V
S
–
) (mV)
0
0
OUTPUT VOLTAGE (V)
0.2
0.6
0.8
1.0
20
1.8
6100 F07
0.4
10
5
25
15 30
1.2
1.4
1.6
V
S
= 4.4V TO 48V
V
CC
= 3V
A
V
= 50V/V
T
A
= 25°C
Figure 6. Expanded View of Output Voltage vs V
SENSE
, A
V
= 10V/V Figure 7. Expanded View of Output Voltage vs V
SENSE
, A
V
= 50V/V