MAX1693 Datasheet, PDF (6/8 Pages) Maxim Integrated Products – USB Current-Limited Switches with Fault Blanking

USB Current-Limited Switches
with Fault Blanking
PIN
1, 3, 9
2, 4, 8, 10
5
6
7
NAME
IN
OUT
ON
GND
FAULT
Pin Description
FUNCTION
Input. P-channel MOSFET source. Connect all IN pins together and bypass with a 1µF
ceramic capacitor to ground.
Switch Output. P-channel MOSFET drain. Connect all OUT pins together and bypass with a
0.1µF capacitor to ground.
Active-Low Switch On Input. A logic low turns the switch on.
Ground
Fault-Indicator Output. This open-drain output goes low when the device is in thermal shut-
down or undervoltage lockout or on a sustained (>10ms) current-limit condition. For the
MAX1694 only, this output latches low when asserted, and the power switch is turned off
until the latch is reset.
IN
FAULT
N
ON
P
OUT
MAX1693
P
REPLICA
AMPLIFIER
ON
P
ON
10ms
TIMER
HOT
CURRENT-LIMIT
AMPLIFIER
1.24V
CONTROL
GND
CIRCUITRY
Figure 1. MAX1693 Functional Diagram
_______________Detailed Description
The MAX1693/MAX1694 P-channel MOSFET power
switches limit output current to 0.7A min to 1.0A max.
When the output current is increased beyond the cur-
rent limit (I_LIMIT), the current also increases through the
replica switch (I_OUT/6500). The current-limit error ampli-
fier compares the voltage to the internal 1.24V refer-
ence and regulates the current back to the I_LIMIT.
These switches are not bidirectional; therefore, the
input voltage must be higher than the output voltage.
Continuous Short-Circuit Protection
The MAX1693/MAX1694 are foldback short circuit-pro-
tected switches. In the event of an output short-circuit
or current-overload condition, the current through the
switch is foldback-current limited to 500mA continuous
for the MAX1693. For the MAX1694, if the short circuit
lasts longer than 10ms, the switch is latched off.
Thermal Shutdown
The MAX1693/MAX1694 feature thermal shutdown. The
switch turns off and the FAULT output goes low imme-
diately (no fault blanking) when the junction tempera-
ture exceeds +165°C. The MAX1694 remains latched
with the switch off and the FAULT output low. When the
MAX1693 cools 20°C, the switch turns back on. If the
fault short-circuit condition is not removed, the switch
will cycle on and off, resulting in a pulsed output.
FAULT Indicator
The MAX1693/MAX1694 provide a fault output
(FAULT). A 100kΩ pull-up resistor from FAULT to IN
provides a logic control signal. This open-drain output
goes low when any of the following conditions occur:
• The input voltage is below the undervoltage-lockout
(UVLO) threshold.
• The die temperature exceeds the thermal shutdown
temperature limit of +165°C.
• The device is in current limit and the 10ms fault-
blanking period is exceeded.
Fault Blanking
The MAX1693/MAX1694 feature 10ms fault blanking.
Fault blanking allows current-limit faults, including
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