Datasheet

ST890 Maximum rating
Doc ID 8649 Rev 9 9/21
2.1 Functional description
2.1.1 Output current limit
I
LIM
is the output current that ST890 device limits under the condition V
O
(output voltage)
> 1.6 V.
When I
LIM
is reached, the FAULT pin is asserted.
2.1.2 Output short-circuit protection
The ST890 device provides short-circuit protection by limiting the output current during
a short circuit event.
I
sc
is the output short-circuit current limit level (typ. 1.2 x I
LIM
). When the output is short-
circuit such as V
O
< 1.6 V, the ST890 device limits the output current to no more than the I
sc
level.
When the output is short-circuit, the FAULT
pin is asserted.
2.1.3 Programming I
LIM
The ST890's I
LIM
can be programmed through the external resistor, R
SET
connected at the
SET pin (pin 5).
I
LIM
is determined by the following relationships:
Equation 1
Equation 2
therefore:
Equation 3
I
SET
V
SET
R
SET
------ ---- ----=
I
LIM
I
SET
-------- --- 1110=
R
SET
1.24
1110
I
LIM
-------- -----
×=