LTC6101HV Linear Technology, LTC6101HV Datasheet - Page 14

• Manufacturer Part Number: LTC6101HV
• Description: High-Side Current Sense Amplifier
• Manufacturer: Linear Technology

LTC6101/LTC6101HV
APPLICATIO S I FOR ATIO
Reverse Supply Protection
Some applications may be tested with reverse-polarity
supplies due to an expectation of this type of fault during
operation. The LTC6101 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
the reverse current through the LTC6101. Note that this
diode will limit the low voltage performance of the LTC6101
by effectively reducing the supply voltage to the part by V
In addition, if the output of the LTC6101 is wired to a device
that will effectively short it to high voltage (such as
through an ESD protection clamp) during a reverse supply
condition, the LTC6101’s output should be connected
through a resistor or Schottky diode (Figure 8).
Response Time
The LTC6101 is designed to exhibit fast response to inputs
for the purpose of circuit protection or signal transmis-
sion. This response time will be affected by the external
circuit in two ways, delay and speed.
14
Figure 7. Schottky Prevents Damage During Supply Reversal
L
O
A
D
4
2
D1
LTC6101
U
+
R
SENSE
–
U
–
3
5
1
(Figure 7). This will limit
W
R1
100
R2
4.99k
6101 F07
U
V
BATT
D
.
If the output current is very low and an input transient
occurs, there may be an increased delay before the output
voltage begins changing. This can be improved by in-
creasing the minimum output current, either by increasing
R
current is illustrated in the step response curves in the
Typical Performance Characteristics section of this
datasheet. Note that the curves are labeled with respect to
the initial output currents.
The speed is also affected by the external circuit. In this
case, if the input changes very quickly, the internal ampli-
fier will slew the gate of the internal output FET (Figure 1)
in order to maintain the internal loop. This results in
current flowing through R
current slew rate will be determined by the amplifier and
FET characteristics as well as the input resistor, R
a smaller R
quickly, decreasing the response time at the output. This
will also have the effect of increasing the maximum output
current. Using a larger R
time, since V
ing R
gain of the circuit.
SENSE
O
D
L
A
OUT
4
2
or decreasing R
D1
will both have the effect of increasing the voltage
LTC6101
Figure 8. Additional Resistor R3 Protects
Output During Supply Reversal
IN
OUT
will allow the output current to increase more
+
R
SENSE
= I
–
OUT
• R
IN
OUT
. The effect of increased output
3
5
1
OUT
IN
R1
100
R2
4.99k
. Reducing R
will decrease the response
and the internal FET. This
R3
1k
V
BATT
IN
ADC
and increas-
IN
6101 F08
. Using
6101fa