MAX4795ETT-T Maxim Integrated, MAX4795ETT-T Datasheet - Page 6

• Manufacturer Part Number: MAX4795ETT-T
• Description: Power Switch ICs - Power Distribution
• Manufacturer: Maxim Integrated

Specifications of MAX4795ETT-T

• Number Of Outputs: 1
• Operating Supply Voltage: 2 V to 4.5 V
• Maximum Operating Temperature: + 85 C
• Package / Case: TDFN EP-6
• Minimum Operating Temperature: - 40 C

450mA/500mA Current-Limit Switches
The MAX4795–MAX4798 are forward/reverse current-
limited switches that operate from a 2V to 4.5V input
voltage range and guarantee a 450mA and 500mA
minimum current-limit threshold for different options.
The voltage drop across an internal sense resistor is
compared to two reference voltages to indicate a for-
ward or reverse current-limit fault. When the load cur-
rent exceeds the preset current limit for greater than
the fault-blanking time, the switch opens.
The MAX4796 and MAX4798 have an autoretry function
that turns on the switch again after an internal retry time
expires. If the faulty load condition is still present after
the blanking time, the switch turns off again and the
cycle is repeated. If the faulty load condition is not pre-
sent, the switch remains on.
The MAX4795 and MAX4797 do not have the autoretry
option and the switch remains in latch-off mode until
the ON pin or the input power is cycled from high to low
and then high again.
The MAX4795–MAX4798 limit the reverse current (V
to V
switch is shut off and FLAG is asserted if the reverse
current-limit condition persists for more than the blanking
time. This feature prevents excessive reverse currents
from flowing through the device.
Toggle ON high to enable the current-limited switches.
The switches are continuously on if there is no fault.
When a forward/reverse current fault is present or the die
exceeds the thermal-shutdown temperature of +150°C,
OUT is internally disconnected from IN and the supply
current decreases to 8µA (latch off). The switch is now
operating in one of its off states. The switch-off state also
occurs when driving ON low, thus reducing the supply
current (shutdown) to 0.01µA. Table 1 illustrates the
ON/OFF state of the MAX4795–MAX4798 current-limit
switches.
Table 1. MAX4795–MAX4798 Switch Truth Table
6
High
High
Low
_______________________________________________________________________________________
ON
IN
) from exceeding the maximum I
Current limit
Thermal
FAULT
Reverse-Current Protection
X
Detailed Description
Switch-On/Off Control
OFF
OFF immediately (t
OFF after t
ON during t
MAX4796 and MAX4798; cycle repeats until fault is removed
REV
BLANK
BLANK
value. The
period has elapsed
period, OFF during t
BLANK
OUT
SWITCH ON/OFF
period does not apply)
The MAX4795–MAX4798 feature a latched output (FLAG).
Whenever an overcurrent condition is encountered,
the MAX4795/MAX4797 latch FLAG low and turn the
switch off. The MAX4796/MAX4798 latch FLAG low and
keep it low until the overcurrent condition is removed.
During this time, the switch cycles on and off in the
autoretry mode. When the overcurrent condition is
removed, FLAG deasserts and the switch turns on
(Figure 2). FLAG is an open-drain output transistor and
requires an external pullup resistor from FLAG to IN.
During shutdown (ON is low), the pulldown on FLAG
output is released to limit power dissipation. FLAG goes
low when any of the following conditions occur:
• The die temperature exceeds the thermal-shutdown
• The device is in current limit for more than the fault-
• The switch is in autoretry.
Figure 2. MAX4796/MAX4798 Autoretry Fault-Blanking Diagram
FLAG PIN
SWITCH
STATUS
STATUS
temperature limit of +150°C.
blanking period.
OFF
ON
RETRY
t
period for the
BLANK
t
RETRY
t
BLANK
SUPPLY CURRENT MODE
See the Autoretry section
FLAG Indicator
Shutdown
Latchoff
Latchoff
t
BLANK
CURRENT
CONDITION
REMOVED
LIMIT
SHORT