MIC2548-2BM TR Micrel Inc, MIC2548-2BM TR Datasheet - Page 11

• Manufacturer Part Number: MIC2548-2BM TR
• Description: IC SW CURR LIMIT HI SIDE 8-SOP
• Manufacturer: Micrel Inc
• Type: High Sider

Specifications of MIC2548-2BM TR

• Input Type: Non-Inverting
• Number Of Outputs: 1
• On-state Resistance: 80 mOhm
• Current - Peak Output: 1.5A
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Current - Output / Channel: -
• Other names: MIC2548-2BMTR; MIC2548-2BMTR

Functional Description
The MIC2544 and MIC2548 are high-side N-channel
switches available with active-high or active-low enable
inputs. Fault conditions turn-off or inhibit turn-on of the
output transistor and activate the open-drain error flag
transistor making it sink current to ground.
Input and Output
IN is the power supply connection to the logic circuitry
and the drain of the output MOSFET. OUT is the source
of the output MOSFET. In a typical circuit, current flows
from IN to OUT toward the load. If VOUT is greater than
VIN, current will flow from OUT to IN since the switch is
bidirectional when enabled.
The output MOSFET and driver circuitry are also
designed to allow the MOSFET source to be externally
forced to a higher voltage than the drain (V
when the switch is disabled. In this situation, the
MIC2544/48 avoids undesirable current flow from OUT
to IN. Both OUT pins must be connected together.
Thermal Shutdown
Thermal shutdown shuts off the output MOSFET and
signals the fault flag if the die temperature exceeds
140°C. 10°C of hysteresis prevents the switch from
turning on until the die temperature drops to 130°C.
Overtemperature detection functions only when the
switch is enabled.
The MIC2548 features an internal latch which causes
the part to remain off after thermal shutdown until a reset
pulse is provided via the enable pin (pin 1). While in
current-limit, the thermal shutdown latch prevents on/off
cycling of the output.
Refer to Figures 2a and 2b for timing diagram. The flag
remains low until reset.
Enable Input
EN must be driven logic high or logic low, or be pulled
high or low for a clearly defined input. Floating the input
may cause unpredictable operation. EN should not be
allowed to go negative with respect to GND, and V
should be less than or equal to V
Micrel, Inc.
April 2010
IN
.
OUT
> V
IN
EN
)
11
Adjustable Current-Limit
The short-circuit current-limit is user-adjustable with an
external set resistor. Current-limit in the range of 100mA
to 1.5A is available with a set point accuracy of better
than ±20%. The current-limit circuit prevents damage to
the output MOSFET and external load.
The nominal current-limit value is set with an external
resistor between ILIM and GND. For a desired current-
limit, the value of the external set resistor is given by:
where:
For example, to set a 1A nominal current-limit, R
calculated as:
Current through R
The voltage across R
impedance comparator to provide an indication of output
current. R
2.29kΩ ±0.5%.
Short-Circuit Protection
In the event of a short circuit, the output current will fold
back to approximately 80% of the short-circuit current-
limit.
Fault Flag
FLG is an N-channel, open-drain MOSFET output.
The faultflag is active (low) for current-limit or thermal
shutdown conditions. The flag output MOSFET is
capable of sinking a 10mA load to typically 100mV
above ground.
154Ω < R
SET
should be between 154Ω ±0.5% and
SET
<2.29kΩ
SET
SET
increases with OUT current.
could be monitored with a high
MIC2544/2548
M9999-043010
SET
is