MIC2041-1YMM Micrel Inc, MIC2041-1YMM Datasheet - Page 14

• Manufacturer Part Number: MIC2041-1YMM
• Description: 75 Mohm Low Voltage Switch -
• Manufacturer: Micrel Inc
• Type: High Side Switchr

Specifications of MIC2041-1YMM

• Number Of Outputs: 1
• Rds (on): 75 mOhm
• Internal Switch(s): Yes
• Current Limit: Adjustable
• Voltage - Input: 0.8 ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 10-MSOP, Micro10™, 10-uMAX, 10-uSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 576-2141; MIC2041-1YMM

MIC2040/2041
Power Dissipation
Power dissipation depends on several factors such as the
load, PCB layout, ambient temperature, and package type.
The following equations can be used to calculate power
dissipation and die temperature.
Calculation of power dissipation can be accomplished by the
following equation:
To relate this to junction temperature, the following equation
can be used:
where T
and R
Printed Circuit Board Hot-Plug
The MIC2040/41 are ideal inrush current limiting power
switches suitable for hot plug applications. Due to the inte-
grated charge pump, the MIC2040/41 present a high imped-
ance when in the off state and the device slowly becomes a
low impedance as it turns on. This effectively isolates power
supplies from highly capacitive loads by reducing inrush
current during hot plug events. This same feature also can be
used for soft-start requirements.
Bus-Powered Hub (USB)
Figure 5 illustrates a bus-powered hub application where the
MIC2040 provides ganged power switching to multiple down-
stream ports. A low-cost MIC5203 (SOT-143) or MIC5207
(TO-92) 3.3V low-dropout (LDO) regulator provides power
from the bus to the USB controller.
PCB Layout Recommendations
The MIC2040 and MIC2041 have very low on-resistance,
typically 50mΩ, and the switches can provide up to 1.5A of
continuous output current. Under maximum load, the power
consumed by the devices may cause the devices to heat up
considerably. The following list contains some useful sug-
gestions for PCB layout design of the MIC2040/41 in order to
prevent the die from overheating under normal operating
conditions.
M9999-012004
P
T
θ(J-A)
J
D
J
= P
= R
= junction temperature, T
VBUS
GND
is the thermal resistance of the package.
D
D+
DS(on)
D-
× R
θ(J-A)
C3
4.7µF
× (I
OUT
+ T
Note:
BothV
BothV
I
LIMIT
IN
MIC5203-3.3
IN
D+
D-
Regulator
= 1.5A.
)
A
IN
OUT
2
pins (7, 9) must be externally tied together.
LDO
GND
Controller
3.3V USB
pins (8, 10) must be externally tied together.
GND
OUT
ON/OFF
A
OC
= ambient temperature
20kΩ
Figure 5. Multi-Port Bus-Powered Hub
C4
1µF
R1
0.1µF
R2
20kΩ
C2
0.1µF
220Ω
C1
(4)
(5)
R
SET
14
7, 9
6
1
2
5
VIN
VBIAS
EN
/FAULT
ILIM
MIC2040-1BM
1. Supply additional copper area under the device
See “Application Hint 17” for a general guideline in
2. Provide additional pad area on the corner pins of
3. Tie the common power pins (V
Ex: For 1A maximum current, design traces for
4. For PCB trace width calculations, there are
GND
to remove heat away from the IC.
calculating the suggested area.
the MIC2040/41 IC for heat distribution.
and V
such that the traces entering and leaving the
device have a uniform width sufficient for the
application’s current requirements plus added
margin (25% minimum recommended).
numerous calculator programs available on the
internet and elsewhere. As a general rule of
thumb, 15-20 mils for every 1A of current when
using 1oz. copper. However, the trace width
calculators often take into account maximum
temperature increase constraints, as well as
layer arrangement, in determining the PCB trace
widths.
4
UVLOIN
1.25A capability.
VOUT
OUT
8,10
3
(OPEN)
= pins 8 and 10) together in a manner
5V@ 1A
V
OUT
C
10µF
LOAD
C
10µF
LOAD
C
10µF
LOAD
IN
Downstream port
Downstream port
Downstream port
= pins 7 and 9
(100mA max.)
(100mA max.)
(100mA max.)
January 2005
Micrel