MAX890LESA-T Maxim Integrated Products, MAX890LESA-T Datasheet - Page 7

• Manufacturer Part Number: MAX890LESA-T
• Description: Current Limit SW 1-IN 1-OUT 2.7V to 5.5V 1.2A 8-Pin SOIC N T/R
• Manufacturer: Maxim Integrated Products

Specifications of MAX890LESA-T

• Package: 8SOIC N
• Input Voltage: 2.7 to 5.5 V
• Maximum Output Current: 1.2(Typ) A
• Number Of Outputs: 1
• Operating Temperature: -40 to 85 °C

Figure 2. Setting the Current Limit
Slow-Loop Response in the Typical Operating
Characteristics.
The MAX890L features thermal shutdown. The switch
turns off when the junction temperature exceeds
+135°C. Once the device cools by 10°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.
The MAX890L provides a fault output (FAULT). This
open-drain output goes low when in current limit or
when the die temperature exceeds +135°C. A 100kΩ
pull-up resistor from FAULT to IN provides a logic-
control signal.
To limit the input voltage drop during momentary output
short-circuit conditions, connect a capacitor from IN to
GND. A 1µF ceramic capacitor will be adequate for
P-Channel Switch with Thermal Shutdown
Applications Information
_______________________________________________________________________________________
MAX890L
Thermal Shutdown
GND
SET
Input Capacitor
Fault Indicator
1.2A, Current-Limited, High-Side
R
SET
most applications; however, higher capacitor values
will further reduce the voltage drop at the input.
Connect a 0.1µF capacitor from OUT to GND. One
function of this capacitor is to prevent inductive para-
sitics from pulling OUT negative during turn-off.
To take full advantage of 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
(no more than 5mm).
Under normal operating conditions, the package can
dissipate and channel heat away. Calculate the maxi-
mum power as follows:
where R
When the output is short circuited, the voltage drop
across the switch equals the input supply. Hence, the
power dissipated across the switch increases, as does
the die temperature. If the fault condition is not
removed, the thermal-overload-protection circuitry turns
the switch off until the die temperature falls by 10°C. A
ground plane in contact with the device will help dissi-
pate additional heat.
TRANSISTOR COUNT: 396
ON
is the on-resistance of the switch.
Layout and Thermal-Dissipation
P = I
2
LIMIT
Chip Information
x R
Output Capacitor
ON
Consideration
7