MIC1344
Smart, 3A, Two-Channel, Power
ORing Switch
General Description Features
The MIC1344 is an advanced two input, one output, hot Two input, one output, power ORing switch
swappable, power multiplexer. It has both automatic and
Input voltage operating range: 2.8V to 5.5V
manual input selection (ENA and ENB) and four status
Automatic and manual input selection modes
outputs.
Four digital and two analog status outputs
In automatic mode, the MIC1344 will automatically connect
Current blocking: output-to-input and input-to-input
the higher of two input voltages (INA or INB), to the output
Low on-resistance (70m typical)
(OUT). In manual mode, either of the two inputs can be
Up to 3A current handling
routed to the output, or both power inputs can be turned off
so that multiple MIC1344s can be used for more than two
Low standby channel current (11A typical)
power inputs.
Separate current limiting and readback for each channel
The MIC1344 has four digital open drain status outputs.
Available in 12-pin, 2mm 2mm, QFN (FTQFN)
The ASEL\ and BSEL\ outputs indicate which input is
package
selected. The STAOK and STBOK outputs indicate the
Thermal-shutdown protection
general health of the input channels. Specifically, these
40C to 125C junction temperature range
outputs will be inactive (high) if the channel has sufficient
input voltage, the channel current is within acceptable
Applications
limits, the die temperature is not too hot, and the channel
Two input to one output power selector
has no reverse current detected.
Multiple inputs to a single output power selector
The current limit for each input channel of the MIC1344
Charger input power selector
can be individually set up to 3A, by two external current-
limit set resistors (ILIMA and ILMIB). The current flowing in Dual battery selector
each of the channels can be read by measuring the
Main and backup power selector
voltage at these resistors.
USB power selector
Datasheets and support documentation are available on
Portable products
Micrels web site at: www.micrel.com.
Supercapacitor ORing
Backup battery diode ORing
Typical Application
Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MIC1344
Ordering Information
(1, 2)
Part Number Marking Output Current Junction Temperature Range Package
MIC1344YFT 4N Adjustable (3.0A maximum) 40C to +125C 12-Pin 2mm 2mm FTQFN
Notes:
1. Pin 1 indicator =
2. Green RoHS compliant package. Lead finish is NiPdAu. Mold compound is halogen free.
Pin Configuration
12-Pin 2mm 2mm FTQFN (FT)
(Top View)
Pin Description
Pin Number Pin Name Pin Function
Supply Voltage Input B. This input may be bypassed to GND with >0.1F, X7R or similar, ceramic
1 INB
type capacitor. This input is hot swappable.
Open drain output, digital status monitor for supply voltage Input B (INB). Voltage will be low if
any of the following conditions occur:
INB is below the UVLO limit.
The output current from INB is at its set current limit.
2 STBOK
The die temperature exceeds the overtemperature limit.
Reverse current detected (V > V +100mV).
OUT INB
Prolonged high hysteresis mode engaged.
3 BSEL\ Open Drain Output. Low if Input B (INB) is providing power to the OUT pin.
A resistor from this pin to ground sets the current limit for INB. The current flowing into INB can be
4 ILIMB
monitored by the voltage on this pin.
The ENA and ENB digital inputs control which voltage input (INA or INB) is connected to the
voltage out (OUT) pin. There is an internal 570k pull-down on this pin to ensure that automatic
5 ENB
select mode is active when the logic that is driving the MIC1344 is being powered up. Table 1
shows how to control the power routing with the ENA and ENB inputs.
6 GND Ground.
April 24, 2015 Revision 1.0
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