MAX14523A_11 Datasheet, PDF (8/11 Pages) Maxim Integrated Products – 250mA to 1.5A, Adjustable Current-Limit Switches

250mA to 1.5A, Adjustable
Current-Limit Switches
IN
THERMAL
SHUTDOWN
BUFFER
Functional Diagram
REVERSE-
CURRENT
PROTECTION
OUT
CONTROL
LOGIC
FLAG
TIMING
N.C.
CIRCUITRY
MAX14523A
MAX14523AL
MAX14523B
MAX14523C
BANDGAP
REFERENCE
CURRENT
LIMIT
ON/(ON)*
BUFFER
SETI
GND
*( ) FOR THE MAX14523AL ONLY
Detailed Description
The MAX14523A/MAX14523AL/MAX14523B/MAX14523C
programmable current-limit switches operate from
+1.7V to +5.5V and provide internal current limiting
adjustable from 250mA to 1.5A. These devices feature
a fixed blanking time, and a FLAG output that notifies
the processor when a fault condition is present.
Programmable Current Limit/Threshold
A resistor from SETI to GND sets the current
limit/threshold for the switch (see the Setting the
Current Limit/Threshold section). If the output current is
limited at the current threshold value for a time equal to
or longer than t_BLANK, the output flag asserts and the
MAX14523A/MAX14523AL enter the autoretry mode,
the MAX14523B latches off the switch, and the
MAX14523C enters the continuous current-limit mode.
Autoretry (MAX14523A/MAX14523AL)
When the forward current reaches the current thresh-
old, the t_BLANK timer begins counting (Figure 2). FLAG
asserts if the overcurrent condition is present for
t_BLANK or longer. The timer resets if the overcurrent
condition disappears before the blanking time (t_BLANK)
has elapsed. A retry time delay (t_RETRY) starts immedi-
ately after the blanking time has elapsed. During that
time, the switch latches off. At the end of t_RETRY, the
switch turns on again. If the fault still exists, the cycle
repeats. If the fault has been removed, the switch stays
on. During this cycle, FLAG stays low. In autoretry, if
the die temperature exceeds +170°C (typ) due to self
heating, the MAX14523A/MAX14523AL go into thermal
shutdown until the die temperature drops by approxi-
mately 15°C (see the Thermal Shutdown section.)
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