MIC2026/2076
Dual-Channel Power Distribution Switch
UL Recognized Com ponent
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
Jul y 2007 M9999-072707
General Description
The MIC2026 and MIC2076 are high-side MOSFET
switches optimized for general-purpose power distribution
requi r ing ci rcuit pr otection.
The MIC2026/76 are internally current limited and have
thermal shutdo wn that pr otects the devic e 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 enabl e input will reset t he dev ic e output.
Both devices employ soft-start circuitry that minimizes
inr ush cur r ent in applications where hi ghly c apac itive loads
are employed.
A fault status output flag is asserted during overcurrent
and thermal shutdown conditions. Transient faults are
internally filtered.
The M IC2026/76 ar e av ailable in 8- pin DIP or 8- pin SOIC.
All support documentation can be found on Micrel’s web
site at www.mic r el.com.
Features
• 140m maxim um on-resi stanc e per c hannel
• 2.7V to 5.5V operating range
• 500mA minimum continuous curr ent per c hannel
• Short c ircuit pr otection with thermal shutdown
• Thermally isolated channels
• Fault status flag with 3m s filter elim inates f alse
assertions
• Undervoltage lockout
• Rev er se cur r ent flow blocki ng ( no “ body di ode” )
• Cir c uit break er mode (MI C2076)
• Logic-compati ble inputs
• Soft-start circuit
• Low quie scent c ur r ent
• Pi n c om patible wit h MIC2526
• UL File # E179633
Applications
• USB peripherals
• Gener al purpose power s witching
• ACPI power distr ibuti on
• 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
V
CC
2.7V to 5.5V
0.1µF
VIN Load
Load
V
CONT.
10k
10k
Micrel, Inc. MIC2026/2076
Jul y 2007 2 M9999-072707
Ordering Information
Part Num ber
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 DI P
MIC2076-2BN — Active Low
–40°C to +85°C
8-Pin DIP
Note:
1. RoHS compliant and Halogen free.
Pin Configuration
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): Logi c-compatible, enable i nput. Active high (-1) or
active low (-2).
2 FLGA Fault Flag A (Output): Acti ve-low, open-drain out put. Indicates overcurrent or
thermal shutdown conditions. Overcurrent conditions must last longer than t
B
D
B
in
order to assert FLGA .
3 FLGB Fault Flag B (Output): Acti ve-low, open-drain out put. Low i ndicates overcurrent
or thermal shutdown condi t ions . Overcurrent condi tions must las t longer th an t
B
D
B
in ord er to asser t F L GB.
4 ENB Switch B Enable (Input): Logi c-compatible enable i nput. Active- high (-1) or
active-low (-2).
5 OUTB Switch B (O utput)
6 GND Ground
7 IN Input: Swit ch and logic suppl y input.
8 OUTA Switch A (O utput)
Micrel, Inc. MIC2026/2076
Jul y 2007 3
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Absolute Maximum Ratings
P
(1)
Suppl y V oltage (V
B
IN
B
).......................................–0.3V to +6V
Fault Flag V oltage (V
B
FLG
B
)............................................. +6V
Fault Flag Cur r ent (I
B
FLG
B
) ............................................ 25mA
Output Voltage (V
B
OUT
B
).................................................. +6V
Out put Curr ent (I
B
OUT
B
)............................... Internally Limi ted
Enabl e Input (I
B
EN
B
)....................................–0.3V to V
IN
+ 3V
Stor age Temper ature (T
B
S
B
).......................–65°C t o +150 ° C
ESD Rati ng
(3)
HBM......................................................................1kV
MM......................................................................200V
Operating Ratings
P
(2)
Suppl y V oltage (V
B
IN
B
)................................... +2.7 V to +5 .5 V
Ambient Temperat ur e (T
B
A
B
)......................... –40° C to +85°C
Junct ion Temper ature Range (T
B
J
B
)............ Internall y Limi ted
Thermal Resistanc e
SOIC (θ
B
JA
B
)......................................................160°C/W
PDIP (θ
B
JA
B
)......................................................105°C/W
Electrical Characteristics
(4)
P
V
B
IN
B
= +5V; T
B
A
B
= 25°C,
bold
values i ndicate –40°C T
B
A
B
+85°C; unless noted
Symbol Parameter Condition Min Typ Max Units
MIC20x6-1, V
B
ENA
B
= V
B
ENB
B
0. 8V
(switch of f), OUT = open 0.75 5 µA
MIC20x6-2, V
B
ENA
B
= V
B
ENB
B
2. 4V
(switch of f), OUT = open 9.5
20
µA
MIC20x6-1, V
B
ENA
B
= V
B
ENB
B
2. 4V
(switch on) , OUT = open 100 160 µA
I
B
DD
B
Supply Cur rent
MIC20x6-2, V
B
ENA
B
= V
B
ENB
B
0. 8V
(switch on) , OUT = open 100 160 µA
low-to-hi gh transition 1.7
2.4
V Enable Input Threshold
high-to- low transition
0.8
1.45 V
V
B
EN
B
Enable Input Hysteresis 250 mV
Enable Input Cur r ent
V
B
EN
B
= 0V to 5.5V
-1
0.01
1
µA I
B
EN
B
Enable Input Capacitance
1 pF
V
B
IN
B
= 5V, I
B
OUT
B
= 500mA
90
140
m
R
B
DS(ON)
B
Sw it ch R es ist anc e
V
B
IN
B
= 3.3V, I
B
OUT
B
= 500mA
100
170
m
Output Leakage Current
MIC20x6-1, V
ENx
0.8V;
MIC20x6-1, V
ENx
2.4V, (output off)
10
µA
OF F Curren t i n Latched
Ther mal S hutdow n
MIC2076
( du r in g ther mal sh utd o wn state)
50 µA
t
B
ON
B
Output Tur n-On Delay
R
B
L
B
= 10, C
B
L
B
= 1µF, see “Timi ng Di agrams”
1.3
5
ms
R
B
L
B
= 10, C
B
L
B
= 1µF, see “Timi ng Di agrams”
0.5
1.15
4.9
ms t
B
R
B
Output Tur n-On Ri se Time
R
B
L
B
= 10, C
B
L
B
= 1µF, see “Timi ng Di agrams” 1. 75
ms
t
B
OFF
B
Output Turn-Off Delay
R
B
L
B
= 10, C
B
L
B
= 1µF, see “Timi ng Di agrams” 35
100
µs
t
B
F
B
Output Turn-Off Fall Time
R
B
L
B
= 10, C
B
L
B
= 1µF, see “Timi ng Di agrams” 32
100
µs
I
B
LIMIT
B
Sho rt-C ircuit Outpu t Curren t
V
B
OUT
B
= 0V, enabled into short-circuit
0.5 0.9 1.25 A
Current-Limit Threshol d ramped load applied to out put
1.0 1.25 A
Short-Circuit Response Time
V
B
OUT
B
= 0V to I
B
OUT
B
= I
B
LIMIT
B
(short applied to output)
20 µs
Micrel, Inc. MIC2026/2076
Jul y 2007 4
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Symbol Parameter Condition Min Typ Max Units
V
B
IN
B
= 5V, apply V
B
OUT
B
= 0V until FLG low
1.5
3
7
ms t
D
Overcurrent Flag Response
Delay
V
B
IN
B
= 3.3V, apply V
B
OUT
B
= 0V until FLG l ow
3 ms
V
B
IN
B
risi ng
2.2
2.4
2.7
V Undervoltage Lockout
Threshold V
B
IN
B
falling
2.0
2.15
2.5
V
I
B
L
B
= 10mA, V
B
IN
B
= 5V
10
25
Error Flag Output Resistance
I
B
L
B
= 10mA, V
B
IN
B
= 3.3V 15
40
Error Flag Off Current V
B
FLAG
B
= 5V 10 µA
T
B
J
B
increasing, each switch
T
B
J
B
decreasing, each switch
140
120 °C
°C
Overtemperature Threshold
P
(5)
P
T
B
J
B
increasing, bot h swit ches
T
B
J
B
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. Sp ecif icati on f or p ac k ag ed pr oduc t 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 approxi m at el y 16 0°C ,
both channels will shut down, even if neither channel is in current limit.
Micrel, Inc. MIC2026/2076
Jul y 2007 5
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Test Circuit
Device
Under
Test C
L
OUT
R
L
V
OUT
Timing Diagrams
90%
V
OUT
10%
90%
10%
t
R
t
F
Output Rise and Fall Times
V
EN
50%
90%
V
OUT
10%
t
OFF
t
ON
Active-Low Switch Del ay Times (MI C20x6-2)
V
EN
50%
90%
V
OUT
10%
t
OFF
t
ON
Active-High Swi t ch Del ay Time (M IC20x6- 1)
Micrel, Inc. MIC2026/2076
Jul y 2007 6
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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
MI C2026/2076 Block Diagram
Functional Description
Input and Output
IN is the power supply connection to the logic circuitry
and the drai n 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 V
OUT
is greater than
V
IN
, 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 drai n (V
OUT
> V
IN
) when the switc h is di sabl ed. In t hi s
situation, the MIC2026/76 prevents undesirable current
flow fro m OU T to IN.
Ther m a l S h ut down
Thermal shutdown is employed to protect the device
from damage should the die temperature exceed safe
margins due m ainly 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
ov erheated c hannel i s in current limit. The ot her channel
is not affected. If however, the die tem perature exceeds
160°C, both channels will be shut off. Upon determining
a therm al shutdown condi tion, t he MI C2076 wi ll latch the
output off. In this case, a pull-up current source is
activated. This allows the output latch to automatically
reset when the l oad (such as a USB dev ic e) is remov ed.
The output can also be reset by toggling EN. Refer to
Figure 1 for timing details.
The M IC2026 will autom atically reset i ts 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 i ncidence of the fault to t he output
MOSFET being shut off. This tim e will be shortest in the
case of a dead short on the output.
Po wer Dissip ati on
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
junc ti on t em per at ur e are found below:
P
D
= R
DS(on)
×
I
OUT2
Total power dissipation of the device will be the
summation of P
D
for both channels. To relate this to
junction temperature,
the following equation can be
used:
Micrel, Inc. MIC2026/2076
Jul y 2007 12
M9999-072707
T
J
= P
D
× θ
JA
+ T
A
where:
T
J
= junction temperature
T
A
= am bient tem per at ur e
θ
JA
= is the thermal r esistanc e of t he pac k age
Curren t S ensi ng and Limi ting
The current-limit threshold is preset internally. The
preset l evel prev ents dam age to the dev i ce and ex ter nal
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 i n the bl ock di agram is v i rt ual and ha s no v olt age
drop. The reaction to an overcurrent condition varies
with t hree scenarios:
Sw itc h Enabled in to Short -Circ uit
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 i ndic ati ng an over c urr ent condit ion.
Short- Circuit Applied to Enabled Out put
When a heavy load or short-circuit is applied to an
enabled switch, a large transient current may flow until
the cur rent-lim it circuitry responds. O nce t his occur s, the
device limits current to less than the short-circuit current
limit specification.
Curre nt- Li mit Response —Ramped Loa d
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
ov ercurrent or thermal shutdown conditi on occur s. In the
case of an overcurrent condition, FLG will be asserted
only after the flag response delay time, t
D
, has elapsed.
This ensures that FLG is asserted only upon valid
ov er cur r ent c onditions and that er r oneous er ror r eport ing
is eliminated. For example, false overcurrent conditions
can occur during hot plug events when a highly
capaci tive load is connect ed and causes a high transient
inr ush curr ent t hat exceeds the c ur rent-limit th reshol d f or
up to 1ms. The FLG response delay time t
D
is typically
3ms.
Undervoltage Lockout
Undervoltage lockout (UVLO) prevents the output
MOSFET from turning on until V
IN
exceeds
approximately 2.5V. Undervoltage detection functions
only when the swit c h is enabled.
V
EN
V
OUT
I
OUT
Short-Circuit Fault
Thermal
Shutdown
Reached
Load and Fault Remove
d
(Output Reset)
V
FLG
I
LIMIT
I
LOAD
3ms typ.
delay
Figure 1. MIC2076-2 Fault Timing: O ut put Reset by Removing Load
V
EN
V
OUT
I
OUT
Short-Circuit Fault
Thermal
Shutdown
Reached
Load/Fault
Removed
V
FLG
I
LOAD
I
LIMIT
3ms typ.
delay
Figure 2. MIC2026 -2 Fault Timing
Micrel, Inc. MIC2026/2076
Jul y 2007 13
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Application Information
Supply Filtering
A 0.1µF to 1µF bypass capaci tor positi oned cl ose t o V
IN
and GND of the device is strongly recommended to
contr ol supply transient s. Wit hout a bypass capacit or, an
output short may cause sufficient ringing on the input
(fr om supply l ead induc tance) to dam age inter nal control
circuitry.
Printed Circuit Board Hot-Plug
The MIC2026/76 are ideal inrush current-limiters for hot
plug appl ications. Due to thei r i ntegrated charge pumps,
the M IC2026/76 present a hi gh im pedance when off and
slowly become a low impedance as their integrated
charge pumps tur n on. Thi s “sof t-start” f eature effectively
isolates power supplies from highly capacitive loads by
reducing inrush current. Figure 3 shows how the
MI C2076 m ay be used i n a card hot- plug appli c ati on.
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 as serted, an ex ter nal RC filter , as sho wn in F i gure
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 t
D(min)
of the
MIC2026/76.
Uni versal Serial Bus (USB) Power Di st rib ution
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). F igure 5 shows a typical USB Host appli cation
that m ay be suit ed f or mobil e PC appli cations em ploying
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 de signing compli ant US B hub and
ho st 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
addit ion, t o reduce volt age droop on the up stream V
BUS
,
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-po wered hub.
ENA OUTA
FLGA
FLGB GND
OUTB
IN
18
27
36
5
USB
Controller
ENB
4
USB Peripheral
Cable
t
o "Hot"
Receptacle
C
BULK
GND
V
BUS
4.7
µF
USB
Function
USB
Function
C
BULK
SPN010012
Figure 3. Hot - Plug Appli cation
Micrel, Inc. MIC2026/2076
Jul y 2007 14 M9999-072707
Fig u re 4. Transie nt Fil ter
Figure 5. USB Two-Port Host Application
Figure 6. USB Two-Port Bus-Powered Hub
Micrel, Inc. MIC2026/2076
Jul y 2007 15 M9999-072707
Package Information
8-Pin SO IC (M )
8-Pin DIP (N)
Micrel, Inc. MIC2026/2076
Jul y 2007 16 M9999-072707
MICRE L, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 US
A
TEL +1 (408) 944-0800 FAX +1 (408) 474- 1000 WEB ht t p://www.m i crel.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 Prod uc ts are not des i gned or au th ori z ed for us e as comp onen ts in life supp or t ap pl i ances, d evices or sys tems wh er e m alfunc ti on of a pr od uc t
can r easonably be exp ec ted t o res ul t in person al injury. Life sup p ort devices or s yst ems are d evices or s yst ems 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 in jur y to the us er. A
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indem nify Micr el for an y d am ag es r esu lting f r om suc h use or sal e.
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