MAX890LESA Datasheet Download

Part No.:
MAX890LESA
Download:
Download Datasheet
Description:
[1A, Current-Limited, High-Side P-Channel Switch with Thermal Shutdown]
File Size:
137 K
Page:
8 Pages
Logo:
Manufacturer:
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
PCB Prototype
 MAX890LESA Datasheet Page:1MAX890LESA Datasheet Page:2MAX890LESA Datasheet Page:3MAX890LESA Datasheet Page:4MAX890LESA Datasheet Page:5MAX890LESA Datasheet Page:6MAX890LESA Datasheet Page:8 
1A, Current-Limited, High-Side
P-Channel Switch with Thermal Shutdown
Output Capacitor
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.
MAX890L
SET
R
SET
GND
MAX890L
Layout and Thermal-Dissipation
Consideration
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:
P = I
2
LIMIT
x R
ON
where R
ON
is the on-resistance of the switch.
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.
Figure 2. Setting the Current Limit
Thermal Shutdown
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.
Fault Indicator
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.
Chip Information
TRANSISTOR COUNT: 396
Applications Information
Input Capacitor
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
most applications; however, higher capacitor values
will further reduce the voltage drop at the input.
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