MAX14575A Datasheet, PDF (10/11 Pages) Maxim Integrated Products – 250mA to 2.5A Adjustable Current-Limit Switches

MAX14575A/MAX14575AL/
MAX14575B/MAX14575C
250mA to 2.5A Adjustable Current-Limit Switches
IN Bypass Capacitor
Connect a minimum 1FF capacitor from IN to GND to
limit the input-voltage drop during momentary output
short-circuit conditions. If the power supply cannot
support the required short-circuit current, then a larger
capacitor should be used to maintain the input voltage
above 2.3V.
If the supply is not strong enough and the user does not
want to use a larger capacitor at the input, then the fol-
lowing circuitry can be used (Figure 4.)
OUT Bypass Capacitor
For stable operation over the full temperature range and
over the full programmable current-limit range, use a 1FF
ceramic capacitor from OUT to ground.
Excessive output capacitance can cause a false over-
current condition due to decreased dV/dt across the
capacitor. Use the following formula to calculate the
maximum capacitive load (CMAX) on OUT:
C_MAX
(µF)
=^ILIM(mA)
×
t _BLANK(MIN)
V_IN(V)
(ms)
For example, for VIN = 5.0V, tBLANK = 10ms, and ILIM =
1000mA, CMAX equals 2000FF.
Layout and Thermal Dissipation
To optimize the switch response time to output short-
circuit conditions, it is very important to keep all traces
as short as possible to reduce the effect of undesirable
parasitic inductance. Place input and output capacitors
as close as possible to the device (should be no more
than 5mm). IN and OUT must be connected with wide
short traces to the power bus. During normal operation,
the power dissipation is small and the package tem-
perature change is minimal. If the output is continuously
shorted to ground at the maximum supply voltage, the
operation of the switches with the autoretry option does
not cause problems because the total power dissipated
during the short is scaled by the duty cycle:
P_(MAX)
=
V_IN(MAX) ×I_OUT(MAX) × t_BLANK
t_RETRY + t_BLANK
Attention must be given to the MAX14575C continuous
current-limit version when the power dissipation during
a fault condition causes the device to reach the thermal-
shutdown threshold.
PROCESS: BiCMOS
Chip Information
1µF
RSETI
IN
OUT
MAX14575A
MAX14575AL
EN(EN) ^MAX14575B
MAX14575C FLAG
SETI
GND
EP
~100I*
Package Information
For the latest package outline information and land patterns
(footprints), go to www.maximintegrated.com/packages. Note
LOAD
that a “+”, “#”, or “-” in the package code indicates RoHS status
only. Package drawings may show a different suffix character, but
the drawing pertains to the package regardless of RoHS status.
PACKAGE
TYPE
8 TDFN-EP
PACKAGE
CODE
T822+2
OUTLINE
NO.
21-0168
LAND
PATTERN NO.
90-0065
PARENTHESES FOR THE MAX14575AL ONLY
*IF V_IN > 3V, A DIODE CAN BE USED IN PLACE OF THE RESISTOR.
Figure 4. Optional Protection for Weak Supply
10  
Maxim Integrated