Datasheet

SENSE OUT
I
SENSE
16 PA
LM5060
V
DS
Fault
Comparator
500:
1 k:
I
OUT-EN
8 PA
V
OUT
V
IN
R
S
R
O
25 mA
max
R
O(MIN)
=
- (R
S
+ 1.5 k:
4 mA
(V
OUT
- V
IN
)
SENSE OUT
I
SENSE
16 PA
LM5060
V
DS
Fault
Comparator
500:
1 k:
I
OUT-EN
8 PA
V
OUT
V
IN
R
S
R
O
4 mA
max
R
S(MIN)
=
V
IN
25 mA
R
O(MIN)
=
V
OUT
- (4 mA x 1.5 k:)
4 mA
LM5060
www.ti.com SNVS628F –OCTOBER 2009–REVISED APRIL 2013
When calculating the minimum R
O
resistor required to limit the current into the OUT pin, the internal current
sources of 8 µA and 16 µA may be neglected. The following formulas can be used to calculate the resistor value
R
O(MIN)
which is necessary to keep the I
O
current to less than 4 mA.
Case A for situations where V
OUT
> V
IN
and reverse polarity situation is present. See Figure 35. V
IN
is negative,
but the voltage at the SENSE pin can roughly be assumed to be 0.0V due to the internal diode from the SENSE
pin to GND.
(16)
In this case, V
IN
also has to be limited to a negative voltage so that reverse current through the SENSE pin does
not exceed 25 mA.
(17)
Figure 36. Current Limiting Resistor in the OUT Path for OUT > SENSE Condition
Case B for situations where V
OUT
> V
IN
and there is no reverse polarity situation present. See Figure 36. V
IN
is
positive and V
OUT
is also positive, but V
OUT
is higher than V
IN
:
(18)
In this case the voltage on the SENSE pin should not exceed 65V.
Case C for situations where V
OUT
< V
IN
and both V
IN
and V
OUT
are positive as well. In such cases there is no risk
of excessive OUT pin current. No current limiting resistors are necessary. Both the SENSE and OUT voltages
should be limited to less than 65V.
Figure 37. Current Limiting Resistor for Negative OUT Conditions
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