MIC2077-2YWMTR [MICREL]
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| 型号： | MIC2077-2YWMTR |
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MICREL SEMICONDUCTOR |
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MIC2027/2077
Quad USB Power Distribution Switch
General Description
Features
The MIC2027 and MIC2077 are quad high-side MOSFET
switches optimized for general-purpose power distribution
requiring circuit protection. The MIC2027/77 are internally
current limited and have thermal shutdown that protects
the device and load.
• 150mΩ maximum on-resistance per channel
• 2.7V to 5.5V operating range
• 500mA minimum continuous current per channel
• Short-circuit protection with thermal shutdown
• Thermally isolated channels
• Fault status flag with 3ms filter eliminates false
assertions
• Undervoltage lockout
The MIC2077 offers “smart” thermal shutdown that
reduces current consumption in fault modes. When a
thermal shutdown fault occurs, the output is latched off
until the faulty load is removed. Removing the load or
toggling the enable input will reset the device output.
• Reverse current flow blocking (no “body diode”)
• Circuit breaker mode (MIC2077) reduces power
Both devices employ soft-start circuitry that minimizes
inrush current in applications where highly capacitive loads
are employed.
consumption
• Logic-compatible inputs
• Soft-start circuit
• Low quiescent current
A fault status output flag is asserted during overcurrent
and thermal shutdown conditions. Transient current limit
faults are internally filtered.
• Pin compatible with MIC2524 and MIC2527
The MIC2027/77 are available in 16-pin narrow (150 mil)
and wide (300 mil) SOIC packages.
Applications
• USB peripherals
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
• General purpose power switching
• ACPI power distribution
• Notebook PCs
• PDAs
• PC card hot swap
Typical Application
®
4-Port Self-Powered Hub
UL Recognized Component
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
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Micrel, Inc.
MIC2027/2077
Ordering Information(1)
Part Number
Enable
Temperature Range
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
Package
Standard
Pb-Free
MIC2027-1BWM
MIC2027-1BM
MIC2027-2BWM
MIC2027-2BM
MIC2077-1BWM
MIC2077-1BM
MIC2077-2BWM
MIC2077-2BM
MIC2027-1YWM
MIC2027-1YM
MIC2027-2YWM
MIC2027-2YM
MIC2077-1YWM
MIC2077-1YM
MIC2077-2YWM
MIC2077-2YM
Active High
Active High
Active Low
Active Low
Active High
Active High
Active Low
Active Low
16-Pin Wide SOIC
16-Pin SOIC
16-Pin Wide SOIC
16-Pin SOIC
16-Pin Wide SOIC
16-Pin SOIC
16-Pin Wide SOIC
16-Pin SOIC
Pin Configuration
16-Pin SOIC (M)
Functional Pinout
16-Pin Wide SOIC (WM)
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MIC2027/2077
Pin Description
Pin Number
Pin Name Pin Function
1
FLG
Fault Flag A (Output): Active-low, open-drain output. Low indicates overcurrent or thermal
shutdown conditions. Overcurrent conditions must last longer than tD to assert flag.
2
3
ENA
OUTA
GND
Switch A Enable (Input): Logic-compatible enable input. Active high (-1) or active low (-2).
Switch A Output
4, 12
5
Ground
IN(C/D)
OUTC
ENC
Input: Channel C and D switch and logic supply input.
Switch C Output
6
7
Switch C Enable (Input)
Fault Flag C (Output)
8
FLGC
FLGD
END
9
Fault Flag D (Output)
10
11
13
14
15
16
Switch D Enable (Input)
Switch D Output
OUTD
IN(A/B)
OUTB
ENB
Supply Input: Channel A and B switch and logic supply input.
Switch B Output
Switch B Enable (Input)
Fault Flag B (Output)
FLGB
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MIC2027/2077
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VIN)............................................ –0.3V +6V
Fault Flag Voltage (VFLG)................................................+6V
Fault Flag Current (IFLG) ..............................................25mA
Output Voltage (VOUT) ....................................................+6V
Output Current (IOUT).................................Internally Limited
Enable Input (IEN) .......................................... –0.3V VIN +3V
Lead Temperature (soldering, 5sec.)......................... 260°C
Storage Temperature (TS).........................–65°C to +150°C
EDS Rating(3)..................................................................1kV
Supply voltage (VIN) ..................................... +2.7V to +5.5V
Ambient Temperature (TA) ..........................–40°C to +85°C
Junction Thermal Range(TJ).....................Internally Limited
Thermal Resistance
[300 mil] Wide SOIC (θJA)................................120°C/W
[150 mil] SOIC (θJA).........................................112°C/W
DIP (θJA) ..........................................................130°C/W
Electrical Characteristics
VIN = +5V; TA = 25°C, bold values indicate –40°C< TA < +85°C, unless noted.
Symbol
Parameter
Condition
Min
Typ
Max
Units
IDD
Supply Current
MIC20x7-1, VENA–D ≤ 0.8V
1.5
10
µA
(switch off), OUT = open
MIC20x7-2, VENA–D ≥ 2.4V
(switch off), OUT = open
1.5
200
200
10
µA
µA
µA
MIC20x7-1, VENA–D ≥ 2.4V
(switch on), OUT = open
320
320
2.4
MIC20x7-2, VENA–D ≤ 0.8V
(switch on), OUT = open
VEN
Enable Input Threshold
low-to-high transition
high-to-low transition
1.7
1.45
250
0.01
1
V
0.8
–1
V
Enable Input Hysteresis
Enable Input Current
Enable Input Capacitance
Switch Resistance
mV
µA
pF
mꢀ
mꢀ
µA
IEN
VEN = 0V to 5.5V
1
RDS(on)
VIN = 5V, IOUT = 500mA
100
110
150
180
10
V
IN = 3.3V, IOUT = 500mA
Output Leakage Current
MIC20x7-1, VENx ≤ 0.8V;
MIC20x7-2, VENx ≥ 2.4V, (output off)
Output Current in
MIC2077 (per Latch Output)
50
µA
Latched Thermal Shutdown
(during thermal shutdown state)
tON
tR
tOFF
tF
Output Turn-On Delay
RL = 10ꢀ, CL = 1µF, see “Timing Diagrams”
RL = 10ꢀ, CL = 1µF, see “Timing Diagrams”
RL = 10ꢀ, CL = 1µF, see “Timing Diagrams”
RL = 10ꢀ, CL = 1µF, see “Timing Diagrams”
VOUT = 0V, enabled into short-circuit
1.3
1.15
35
5
ms
ms
µs
µs
A
Output Turn-On Rise Time
Output Turnoff Delay
4.9
100
100
1.25
1.25
Output Turnoff Fall Time
Short-Circuit Output Current
Current-Limit Threshold
Short-Circuit Response Time
32
ILIMIT
0.5
0.9
1.0
20
ramped load applied to output
A
V
OUT = 0V to IOUT = ILIMIT
µs
(short applied to output)
tD
Overcurrent Flag Response
Delay
VIN = 5V, apply VOUT = 0V until FLG low
1.5
3
3
7
ms
ms
V
IN = 3.3V, apply VOUT = 0V until FLG low
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MIC2027/2077
Symbol
Parameter
Condition
Min
2.2
2.0
Typ
2.4
2.15
10
Max
2.7
2.5
25
Units
V
Undervoltage Lockout
Threshold
VIN rising
V
IN falling
V
Error Flag Output Resistance
IL = 10mA, VIN = 5V
IL = 10mA, VIN = 3.3V
VFLAG = 5V
ꢀ
15
40
ꢀ
Error Flag Off Current
10
µA
Overtemperature Threshold
Note 4
TJ increasing, each switch
TJ decreasing, each switch
140
120
°C
°C
TJ increasing, both switches
TJ decreasing, both switches
160
150
°C
°C
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
4. If there is an output current limit fault on one channel, that channel will shut down when the die reaches approximately 140°C. If the diereaches
approximately 160°C, the other channel driven by the same input will shut down, even if neither channel is in current limit.
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MIC2027/2077
Test Circuit
Timing Diagrams
Output Rise and Fall Times
Active-Low Switch Delay Times (MIC20x7-2)
Active-High Switch Delay Times (MIC20x7-1)
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MIC2027/2077
Typical Characteristics
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MIC2027/2077
Typical Characteristics (cont.)
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Micrel, Inc.
MIC2027/2077
Functional Characteristics
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Micrel, Inc.
MIC2027/2077
Functional Characteristics (cont.)
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MIC2027/2077
Functional Characteristics (cont.)
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Micrel, Inc.
MIC2027/2077
Block Diagram
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MIC2027/2077
where:
Functional Description
TJ = junction temperature
TA = ambient temperature
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 (VOUT > VIN) when the switch is disabled. In this
situation, the MIC2027/77 prevents undesirable current
flow from OUT to IN.
θ
JA = is the thermal resistance of the package
Current Sensing and Limiting
The current-limit threshold is preset internally. The
preset level prevents damage to the device and external
load but still allows a minimum current of 500mA to be
delivered to the load.
The current-limit circuit senses a portion of the output
MOSFET switch current. The current-sense resistor
shown in the block diagram is virtual and has no voltage
drop. The reaction to an overcurrent condition varies
with three scenarios:
Thermal Shutdown
Thermal shutdown is employed to protect the device
from damage should the die temperature exceed safe
margins due mainly to short circuit faults. Each channel
employs its own thermal sensor. Thermal shutdown
shuts off the output MOSFET and asserts the FLG
output if the die temperature reaches 140°C and the
overheated channel is in current limit. The other
channels are not affected. If however, the die
temperature exceeds 160°C, all channels will be shut off.
Upon determining a thermal shutdown condition, the
MIC2077 will latch the output off and activate a pull-up
current source. When the load is removed, this current
source will pull the output up and reset the latch.
Toggling EN will also reset the latch.
Switch Enabled into Short-Circuit
If a switch is enabled into a heavy load or short-circuit,
the switch immediately enters into a constant-current
mode, limiting the output voltage. The FLG signal is
asserted indicating an overcurrent condition.
Short-Circuit Applied to Enabled Output
When a heavy load or short-circuit is applied to an
enabled switch, a large transient current may flow until
the current-limit circuitry responds. Once this occurs the
device limits current to less than the short-circuit current
limit specification.
Current-Limit Response—Ramped Load
The MIC2027 will automatically reset its output when the
die temperature cools down to 120°C. The MIC2027
output and FLG signal will continue to cycle on and off
until the device is disabled or the fault is removed.
Figure 2 depicts typical timing.
The MIC2027/77 current-limit profile exhibits a small
fold-back effect of about 100mA. Once this current-limit
threshold is exceeded the device switches into a
constant current mode. It is important to note that the
device will supply current up to the current-limit
threshold.
Depending on PCB layout, package, ambient
temperature, etc., it may take several hundred
milliseconds from the incidence of the fault to the output
MOSFET being shut off. This time will be shortest in the
case of a dead short on the output.
Fault Flag
The FLG signal is an N-channel open-drain MOSFET
output. FLG is asserted (active-low) when either an
overcurrent or thermal shutdown condition occurs. In the
case of an overcurrent condition, FLG will be asserted
only after the flag response delay time, tD, has elapsed.
This ensures that FLG is asserted only upon valid
overcurrent conditions and that erroneous error reporting
is eliminated. For example, false overcurrent conditions
can occur during hot-plug events when a highly
capacitive load is connected and causes a high transient
inrush current that exceeds the current-limit thresh-old.
The FLG response delay time tD is typically 3ms.
Power Dissipation
The device’s junction temperature depends on several
factors such as the load, PCB layout, ambient
temperature and package type. Equations that can be
used to calculate power dissipation of each channel and
junction temperature are found below.
2
PD = RDS(on) × IOUT
Total power dissipation of the device will be the
summation of PD for all channels. To relate this to
junction temperature, the following equation can be
used:
Undervoltage Lockout
Undervoltage lockout (UVLO) prevents the output
MOSFET from turning on until VIN exceeds approx-
imately 2.5V. Undervoltage detection functions only
when the switch is enabled.
TJ = PD × θJA + TA
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MIC2027/2077
Figure 1. MIC2077-2 Fault Timing: Output Reset by Removing Load
Short-Circuit Fault
VEN
Load/Fault
Removed
VOUT
ILIMIT
ILOAD
IOUT
Thermal
Shutdown
Reached
3ms typ.
delay
VFLG
Figure 2. MIC2207-2 Fault Timing
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Micrel, Inc.
MIC2027/2077
being asserted, an external RC filter, as shown in Figure
3, can be used to filter out transient FLG assertion. The
value of the RC time constant should be selected to
match the length of the transient, less tD(min) of the
MIC2027/77.
Application Information
Supply Filtering
A 0.1µF to 1µF bypass capacitor positioned close to VIN
and GND of the device is strongly recommended to
control supply transients. Without a bypass capacitor, an
output short may cause sufficient ringing on the input
(from supply lead inductance) to damage internal control
circuitry.
Universal Serial Bus (USB) Power Distribution
The MIC2027/77 is ideally suited for USB (Universal
Serial Bus) power distribution applications. The USB
specification defines power distribution for USB host
systems such as PCs and USB hubs. Hubs can either
be self-powered or bus-powered (that is, powered from
the bus). The requirement for USB self-powered hubs is
that the port must supply a minimum of 500mA at an
output voltage of 5V ±5%. In addition, the output power
delivered must be limited to below 25VA. Upon an
overcurrent condition, the host must also be notified. To
support hot-plug events, the hub must have a minimum
of 120µF of bulk capacitance, preferably low ESR
electrolytic or tantulum. Please refer to Application Note
17 for more details on designing compliant USB hub and
host systems.
Printed Circuit Board Hot-Plug
The MIC2027/77 are ideal inrush current-limiters for hot-
plug applications. Due to the integrated charge pump,
the MIC2027/77 present a high impedance when off and
slowly becomes a low impedance as it turns on. This
“soft-start” feature effectively isolates power supplies
from highly capacitive loads by reducing inrush current.
In cases of extremely large capacitive loads (>400µF),
the length of the transient due to inrush current may
exceed the delay provided by the integrated filter. Since
this inrush current exceeds the current-limit flag delay
specification, FLG will be asserted during this time. To
prevent the logic controller from responding to FLG
Figure 3. Transient Filter
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MIC2027/2077
Package Information
16-Pin SOIC (M)
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Micrel, Inc.
MIC2027/2077
16-Pin Wide SOIC (WM)
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http:/www.micrel.com
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its
use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product
can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant
into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A
Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully
indemnify Micrel for any damages resulting from such use or sale.
© 2001 Micrel, Incorporated.
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