MIC2026/2076
Dual-Channel Power Distribution Switch
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
June 2010 M9999-060410-B
General Description
The MIC2026 and MIC2076 are high-side MOSFET
switches optimized for general-purpose power distribution
requiring circuit protection.
The MIC2026/76 are internally current limited and have
thermal shutdown that protects the device and load.
The MIC2076 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.
Both devices employ soft-start circuitry that minimizes
inrush current in applications where highly capacitive loads
are employed.
A fault status output flag is asserted during overcurrent
and thermal shutdown conditions. Transient faults are
internally filtered.
The MIC2026/76 are available in 8-pin DIP or 8-pin SOIC.
All support documentation can be found on Micrel’s web
site at www.micrel.com.
Features
• 140m maximum on-resistance per channel
• 2.7V to 5.5V operating range
• 500mA minimum continuous current per channel
• Shortcircuit protection with thermal shutdown
• Thermally isolated channels
• Fault status flag with 3ms filter eliminates false
assertions
• Undervoltage lockout
• Reverse current flow blocking (no “body diode”)
• Circuit breaker mode (MIC2076)
• Logic-compatible inputs
• Soft-start circuit
• Low quiescent current
• Pin compatible with MIC2526
• UL File # E179633
Applications
• USB peripherals
• General purpose power switching
• ACPI power distribution
• Notebook PCs
• PDAs
• PC card hot swap
___________________________________________________________________________________________________________
Typical Application
ENA OUTA
FLGAI N
FLGB GND
ENB OUTB
ON/OFF
OVERCURRENT
OVERCURRENT
ON/OFF
MIC2026-2
Logic Controller
VCC
2.7V to 5.5V
0.1µF
VIN Load
Load
VCONT.
10k
10k
Micrel, Inc. MIC2026/2076
June 2010 2 M9999-060410-B
Ordering Information
Part Number
Standard Pb-Free
Enable Temperature
Range Package
MIC2026-1BM MIC2026-1YM(1) Active High 8-Pin SOIC
MIC2026-2BM MIC2026-2YM(1) Active Low 8- Pin SOIC
MIC2026-1BN — Active High 8- Pin DIP
MIC2026-2BN — Active Low 8- Pin DIP
MIC2076-1BM MIC2076-1YM(1) Active High 8- Pin SOIC
MIC2076-2BM MIC2076-2YM(1) Active Low 8- Pin SOIC
MIC2076-1BN — Active High 8-Pin DIP
MIC2076-2BN — Active Low
–40°C to +85°C
8-Pin DIP
Note:
1. RoHS compliant and Halogen free.
Pin Configur ation
1ENA
FLGA
FLGB
ENB
8OUTA
IN
GND
OUTB
7
6
5
2
3
4
8-Pin SOIC (M)
8-Pin DIP (N)
Pin Description
Pin Number Pin Name Pin Function
1 ENA
Switch A Enable (Input): Logic-compatible, enable input. Active high (-1) or
active low (-2).
2 FLGA
Fault Flag A (Output): Active-low, open-drain output. Indicates overcurrent or
thermal shutdown conditions. Overcurrent conditions must last longer than tBDB in
order to assert FLGA.
3 FLGB
Fault Flag B (Output): Active-low, open-drain output. Low indicates overcurrent
or thermal shutdown conditions. Overcurrent conditions must last longer than tBDB
in order to assert FLGB.
4 ENB
Switch B Enable (Input): Logic-compatible enable input. Active-high (-1) or
active-low (-2).
5 OUTB Switch B (Output)
6 GND Ground
7 IN Input: Switch and logic supply input.
8 OUTA Switch A (Output)
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June 2010 3 M9999-060410-B
Absolute Maximum RatingsP
(1)
Supply Voltage (VBINB)........................................ –0.3V to +6V
Fault Flag Voltage (VBFLGB)................................................+6V
Fault Flag Current (IBFLGB) ..............................................25mA
Output Voltage (VBOUTB) ....................................................+6V
Output Current (IBOUTB) .................................Internally Limited
Enable Input (IBENB) ..................................... –0.3V to VIN + 3V
Storage Temperature (TBSB)........................–65°C to +150 °C
ESD Rating(3)
HBM......................................................................... 1kV
MM.........................................................................200V
Operating RatingsP
(2)
Supply Voltage (VBINB)..................................... +2.7V to +5.5V
Ambient Temperature (TBAB) .......................... –40°C to +85°C
Junction Temperature Range (TBJB)............. Internally Limited
Thermal Resistance
SOIC (θBJAB) ........................................................160°C/W
PDIP (θBJAB) ........................................................105°C/W
Electrical Characteristics(4)
P
VBINB = +5V; TBAB = 25°C, bold values indicate –40°C TBAB +85°C; unless noted
Symbol Parameter Condition Min Typ Max Units
MIC20x6-1, VBENA B= VBENB B 0.8V
(switch off), OUT = open
0.75 5 µA
MIC20x6-2, VBENA B= VBENB B 2.4V
(switch off), OUT = open
9.5
20 µA
MIC20x6-1, VBENA B= VBENB B 2.4V
(switch on), OUT = open
100 160 µA
IBDDB Supply Current
MIC20x6-2, VBENA B= VBENB B 0.8V
(switch on), OUT = open
100 160 µA
low-to-high transition 1.7 2.4 V Enable Input Threshold
high-to-low transition 0.8 1.45 V
VBENB
Enable Input Hysteresis 250 mV
Enable Input Current VBENB = 0V to 5.5V -1 0.01 1 µA
IBENB
Enable Input Capacitance 1 pF
VBINB = 5V, IBOUTB = 500mA 90
140 m RBDS(ON)B Switch Resistance
VBINB = 3.3V, IBOUTB = 500mA 100
170 m
Output Leakage Current MIC20x6-1, VENx 0.8V;
MIC20x6-1, VENx 2.4V, (output off)
10 µA
OFF Current in Latched
Thermal Shutdown
MIC2076
(during thermal shutdown state)
50 µA
tBONB Output Turn-On Delay RBLB = 10, CBLB = 1µF, see “Timing Diagrams” 1.3 5 ms
RBLB = 10, CBLB = 1µF, see “Timing Diagrams” 0.5 1.15 4.9 ms tBRB Output Turn-On Rise Time
RBLB = 10, CBLB = 1µF, see “Timing Diagrams” 1.75 ms
tBOFFB Output Turn-Off Delay RBLB = 10, CBLB = 1µF, see “Timing Diagrams” 35 100 µs
tBFB Output Turn-Off Fall Time RBLB = 10, CBLB = 1µF, see “Timing Diagrams” 32 100 µs
IBLIMITB Short-Circuit Output Current VBOUTB = 0V, enabled into short-circuit 0.5 0.9 1.25 A
Current-Limit Threshold ramped load applied to output 0.65 1.0 1.25 A
Short-Circuit Response Time VBOUTB = 0V to IBOUTB = IBLIMITB
(short applied to output)
20 µs
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June 2010 4 M9999-060410-B
Symbol Parameter Condition Min Typ Max Units
VBINB = 5V, apply VBOUTB = 0V until FLG low 1.5 3 7 ms
tD Overcurrent Flag Response
Delay VBINB = 3.3V, apply VBOUTB = 0V until FLG low 3 ms
VBINB rising 2.2 2.4 2.7 V Undervoltage Lockout
Threshold VBINB falling 2.0 2.15 2.5 V
IBLB = 10mA, VBINB = 5V 10
25 Error Flag Output Resistance
IBLB = 10mA, VBINB = 3.3V 15 40
Error Flag Off Current VBFLAGB = 5V 10 µA
TBJB increasing, each switch
TBJB decreasing, each switch
140
120
°C
°C
Overtemperature ThresholdP
(5)
P
TBJB increasing, both switches
TBJB 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.
4. Specification for packaged product only.
5. If there is a fault on one channel, that channel will shut down when the die reaches approximately 140°C. If the die reaches approximately 160°C,
both channels will shut down, even if neither channel is in current limit.
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June 2010 5 M9999-060410-B
Test Circuit
Device
Under
Test
CL
OUT
RL
VOUT
Timing Diagrams
90%
VOUT
10%
90%
10%
tRtF
Output Rise and Fall Times
VEN
50%
90%
VOUT
10%
tOFF
tON
Active-Low Switch Delay Times (MIC20x6-2)
VEN 50%
90%
VOUT
10%
tOFF
tON
Active-High Switch Delay Time (MIC20x6-1)
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Typical Characteristics
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Typical Characteristics (continue)
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Functional Characteristics
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Functional Characteristics (continue)
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Functional Characteristics (continue)
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Block Diagram
1.2V
REFERENCE
THERMAL
SHUTDOWN
CHARGE
PUMP
OUTB
UVLO
GATE
CONTROL
IN
ENA
GATE
CONTROL
OUTA
FLGB
CHARGE
PUMP
ENB
OSC.
FLGA
CURRENT
LIMIT
CURRENT
LIMIT
GND
MIC2026/2076
FLAG
RESPONSE
DELAY
FLAG
RESPONSE
DELAY
MIC2026/2076 Block Diagra m
Functional Description
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 MIC2026/76 prevents undesirable current
flow from OUT to IN.
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 channel
is not affected. If however, the die temperature exceeds
160°C, both channels will be shut off. Upon determining
a thermal shutdown condition, the MIC2076 will latch the
output off. In this case, a pull-up current source is
activated. This allows the output latch to automatically
reset when the load (such as a USB device) is removed.
The output can also be reset by toggling EN. Refer to
Figure 1 for timing details.
The MIC2026 will automatically reset its output when the
die temperature cools down to 120°C. The MIC2026
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.
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.
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:
PD = RDS(on) × IOUT
2
Total power dissipation of the device will be the
summation of PD for both channels. To relate this to
junction temperature, the following equation can be
used:
Micrel, Inc. MIC2026/2076
June 2010 12 M9999-060410-B
TJ = PD × θJA + TA
where:
TJ = junction temperature
TA = ambient temperature
θJA = 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:
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, reducing 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 MIC2026/76 current-limit profile exhibits a small
foldback effect of about 200mA. 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.
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 threshold for
up to 1ms. The FLG response delay time tD is typically
3ms.
Undervoltage Lockout
Undervoltage lockout (UVLO) prevents the output
MOSFET from turning on until VIN exceeds
approximately 2.5V. Undervoltage detection functions
only when the switch is enabled.
VEN
VOUT
IOUT
Short-Circuit Fault
Thermal
Shutdown
Reached
Load and Fault Removed
(Output Reset)
VFLG
ILIMIT
ILOAD
3ms typ.
delay
Figure 1. MIC2076-2 Faul t Timing: Output Reset by Removing Load
VEN
VOUT
IOUT
Short-Circuit Fault
Thermal
Shutdown
Reached
Load/Fault
Removed
VFLG
ILOAD
ILIMIT
3ms typ.
delay
Figure 2. MIC2026-2 Faul t Timing
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June 2010 13 M9999-060410-B
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.
Printed Circuit Board Hot-Plug
The MIC2026/76 are ideal inrush current-limiters for hot
plug applications. Due to their integrated charge pumps,
the MIC2026/76 present a high impedance when off and
slowly become a low impedance as their integrated
charge pumps turn on. This “soft-start” feature effectively
isolates power supplies from highly capacitive loads by
reducing inrush current. Figure 3 shows how the
MIC2076 may be used in a card hot-plug application.
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 delay
specification, FLG will be asserted during this time. To
prevent the logic controller from responding to FLG
being asserted, an external RC filter, as shown in Figure
4, 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
MIC2026/76.
Universal Serial Bus (USB) Power Distribution
The MIC2026/76 are 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). Figure 5 shows a typical USB Host application
that may be suited for mobile PC applications employing
USB. The requirement for USB host systems 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.
For bus-powered hubs, USB requires that each
downstream port be switched on or off under control by
the host. Up to four downstream ports each capable of
supplying 100mA at 4.4V minimum are allowed. In
addition, to reduce voltage droop on the upstream VBUS,
soft-start is necessary. Although the hub can consume
up to 500mA from the upstream bus, the hub must
consume only 100mA max at start-up, until it
enumerates with the host prior to requesting more
power. The same requirements apply for bus-powered
peripherals that have no downstream ports. Figure 6
shows a bus-powered hub.
ENA OUTA
FLGA
FLGB GND
OUTB
IN
18
27
36
5
USB
Controller
ENB
4
USB Peripheral
Cable
t
o "Hot"
Receptacle
CBULK
GND
VBUS
4.7
µF
USB
Function
USB
Function
CBULK
SPN010012
Figure 3. Hot-Plug Application
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June 2010 14 M9999-060410-B
Figure 4. Transient Filter
Figure 5. USB Two-Port Host Application
Figure 6. USB Two-Port Bus-Powered Hub
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June 2010 15 M9999-060410-B
Package Information
8-Pin SOIC (M)
8-Pin DIP (N)
Micrel, Inc. MIC2026/2076
June 2010 16 M9999-060410-B
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
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indemnify Micrel for any damages resulting from such use or sale.
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