Fixed Adjustable Current Limiting Power Distribution Switches MIC

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Fixed Adjustable Current Limiting Power Distribution Switches MIC

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MIC20XX Family
Fixed Adjustable Current Limiting Power Distribution Switches
MIC20XX family switches current limiting, high-side power switches, designed general purpose power distribution control digital televisions (DTV), printers, boxes (STB), PCs, PDAs, other peripheral devices. Functionality Table page Configuration Drawings page MIC20XX family's primary functions current limiting power switching. They thermally protected will shutdown should their internal temperature reach unsafe levels, protecting both device load, under high current fault conditions Features include fault reporting, fault blanking eliminate noise-induced false alarms, output slew rate limiting, under voltage detection, automatic-on output, enable with choice either active active high enable. self-contained, with fixed user adjustable current limit. MIC20XX family ideal system where current limiting power control desired. MIC201X subfamily offers unique patented feature: KICKSTARTTM, which allows momentary high current surges secondary current limit (ILIMIT_2nd) without sacrificing overall system safety. MIC20XX family offered, depending desired features, space saving 5-pin SOT-23, 6-pin SOT-23, packages. Data sheets support documentation found Micrel's site www.micrel.com.
Features
typical on-resistance 170m typical on-resistance (MIC2005A) Enable active high active 2.5V 5.5V operating range Pre-set current limit values 0.5A, 0.8A, 1.2A User adjustable current limit from 0.2A 2.1A Under voltage lock-out (UVLO) Variable UVLO allows adjustable UVLO thresholds Automatic load discharge capacitive loads Soft start prevents large current inrush Adjustable slew rate allows custom slew rates Automatic-on output after fault Thermal Protection
Available some family members
Applications
Digital televisions (DTV) boxes PDAs Printers IEEE 1394 power distribution Desktop laptop Game consoles Docking stations
Typical Application
Supply Logic Controller ON/OFF OVERCURRENT/ MIC20X5
(1,3)
VOUT
(2,3)
VBUS 120µF Port
IADJ
FAULT/
Figure Typical Application Circuit
Notes: Depending family member this function FAULT/, IADJ, VUVLO. Depending family member this function IADJ, CSLEW. Configuration Functional Diagram.
KICKSTART trademark Micrel, Inc. MicroLeadFrame registered trademarks Amkor Technology, Inc. CableCARD trademark CableLabs.
Protected U.S. Patent 7,170,732
Micrel Inc. 2180 Fortune Drive Jose, 95131 (408) 944-0800 (408) 474-1000 http://www.micrel.com
January 2009
M9999-012109-A
Micrel, Inc.
MIC20XX Family
Ordering Information
MIC2003/2013
Part Number
Marking FD05 FD08 FD12 FL05 FL08 FL12
Current Limit 0.5A 0.8A 1.2A 0.5A 0.8A 1.2A 0.5A 0.8A 1.2A 0.5A 0.8A 1.2A
Kickstart
Package 5-Pin SOT-23
MIC2003-0.5YM5 MIC2003-0.8YM5 MIC2003-1.2YM5 MIC2003-0.5YML MIC2003-0.8YML MIC2003-1.2YML MIC2013-0.5YM5 MIC2013-0.8YM5 MIC2013-1.2YM5 MIC2013-0.5YML MIC2013-0.8YML MIC2013-1.2YML
6-Pin
5-Pin SOT-23 6-Pin
MIC2004/2014
Part Number
Marking FE05 FE08 FE12 FM05 FM08 FM12
Current Limit 0.5A 0.8A 1.2A 0.5A 0.8A 1.2A 0.5A 0.8A 1.2A 0.5A 0.8A 1.2A
Kickstart
Package 5-Pin SOT-23
MIC2004-0.5YM5 MIC2004-0.8YM5 MIC2004-1.2YM5 MIC2004-0.5YML MIC2004-0.8YML MIC2004-1.2YML MIC2014-0.5YM5 MIC2014-0.8YM5 MIC2014-1.2YM5 MIC2014-0.5YML MIC2014-0.8YML MIC2014-1.2YML
Notes:
6-Pin
5-Pin SOT-23 6-Pin
MIC20XX Family parts RoHS compliant lead free. Over/Under-bar symbol scale. package over/under symbol begins above/below first character marking.
January 2009
M9999-012109-A
Micrel, Inc.
MIC20XX Family
Ordering Information (continued)
MIC2005
Part Number
Marking FF05 FF08 FF12
Current Limit 0.5A 0.8A 1.2A 0.5A 0.8A 1.2A
Enable Active High Active High Active High Active High Active High Active High
Kickstart
Package 6-Pin SOT-23
MIC2005-0.5YM6 MIC2005-0.8YM6 MIC2005-1.2YM6 MIC2005-0.5YML MIC2005-0.8YML MIC2005-1.2YML
6-Pin
MIC2005L
Part Number
Marking 5LFF 8LFF 4LFF
Current Limit 0.5A 0.8A 1.2A
Enable Active Active Active
Kickstart
Package 5-Pin SOT-23
MIC2005-0.5LYM5 MIC2005-0.8LYM5 MIC2005-1.2LYM5
MIC2005A
Part Number
Marking FA51 FA52 FA53 FA54
Current Limit 0.5A 0.5A 0.5A 0.5A
Enable Active High Active Active High Active
Kickstart
Package 5-Pin SOT-23
MIC2005A-1YM5 MIC2005A-2YM5 MIC2005A-1YM6 MIC2005A-2YM6
6-Pin SOT-23
MIC2015
Part Number
Marking FN05 FN08 FN12
Current Limit 0.5A 0.8A 1.2A 0.5A 0.8A 1.2A
Enable Active High Active High Active High Active High Active High Active High
Kickstart
Package 6-Pin SOT-23
MIC2015-0.5YM6 MIC2015-0.8YM6 MIC2015-1.2YM6 MIC2015-0.5YML MIC2015-0.8YML MIC2015-1.2YML
Notes:
6-Pin
MIC20XX Family parts RoHS compliant lead free. Over/Under-bar symbol scale. package over/under symbol begins above/below first character marking.
January 2009
M9999-012109-A
Micrel, Inc.
MIC20XX Family
Ordering Information (continued)
MIC2006/2016
Part Number
Marking FG05 FG08 FG12 FP05 FP08 FP12
Current Limit 0.5A 0.8A 1.2A 0.5A 0.8A 1.2A 0.5A 0.8A 1.2A 0.5A 0.8A 1.2A
Kickstart
Package 6-Pin SOT-23
MIC2006-0.5YM6 MIC2006-0.8YM6 MIC2006-1.2YM6 MIC2006-0.5YML MIC2006-0.8YML MIC2006-1.2YML MIC2016-0.5YM6 MIC2016-0.8YM6 MIC2016-1.2YM6 MIC2016-0.5YML MIC2016-0.8YML MIC2016-1.2YML
Notes:
6-Pin
6-Pin SOT-23 6-Pin
MIC20XX Family parts RoHS compliant lead free. Over/Under-bar symbol scale. package over/under symbol begins above/below first character marking.
January 2009
M9999-012109-A
Micrel, Inc.
MIC20XX Family
Ordering Information (continued)
MIC2007/2017
Part Number
Marking FHAA FQAA
Current Limit
Kickstart
Package 6-Pin SOT-23 6-Pin 6-Pin SOT-23 6-Pin
MIC2007YM6 MIC2007YML MIC2017YM6 MIC2017YML
0.2A 2.0A
MIC2008/2018
Part Number
Marking FJAA FRAA
Current Limit
Kickstart
Package 6-Pin SOT-23 6-Pin 6-Pin SOT-23 6-Pin
MIC2008YM6 MIC2008YML MIC2018YM6 MIC2018YML
0.2A 2.0A
MIC2009/2019
Part Number
Marking FKAA FSAA
Current Limit
Kickstart
Package 6-Pin SOT-23 6-Pin 6-Pin SOT-23 6-Pin
MIC2009YM6 MIC2009YML MIC2019YM6 MIC2019YML
Notes:
0.2A 2.0A
MIC20XX Family parts RoHS compliant lead free. Over/Under-bar symbol scale. package over/under symbol begins above/below first character marking.
January 2009
M9999-012109-A
Micrel, Inc.
MIC20XX Family
MIC20XX Family Member Functionality
Part Number Normal Limiting 2003 2004 2005 2005L 2005A-1 2005A-2 2006 2007 2008 2009
Notes:
Function
Kickstart 2013 2014 2015
Limit
ILIMIT
ENABLE High
ENABLE
CSLEW
FAULT/
VUVLO
Load Discharge
Fixed
2016 2017 2018 2019 Adj.
Kickstart provides alternate start-up behavior; however, pin-outs identical. Kickstart available. Fixed Factory programmed current limit. Adj. User adjustable current limit. VUVLO Variable UVLO (Previously called DML). CSLEW available 5-pin package.
MIC20XX Family Member Configuration Table
Part Number Normal Limiting 2003 2004 2005 2005L 2005A 2006 2007 2008 2009
Notes:
Number Limit Fixed
Kickstart 2013 2014 2015
FAULT/ FAULT/ FAULT/ VUVLO IADJ IADJ FAULT/
CSLEW CSLEW CSLEW
VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT VOUT
2016 2017 2018 2019 Adj.
CSLEW CSLEW CSLEW IADJ
Kickstart available. Fixed Factory programmed current limit. Adj. User adjustable current limit. VUVLO Variable UVLO (Previously called DLM). CSLEW available 5-pin package.
January 2009
M9999-012109-A
Micrel, Inc.
MIC20XX Family
MIC20XX Family Member Configuration Drawings
Fixed Current Limit
VOUT
VOUT
(Top View)
MIC20X3
ENABLE
VOUT
VOUT
ENABLE
(Top View)
MIC20X4
ENABLE
VOUT
VOUT CSLEW FAULT/
VOUT CSLEW FAULT/
ENABLE
FAULT/
ENABLE
(Top View)
MIC2005-X.XL MIC2005A MIC20X5 MIC20X5
ENABLE
VOUT CSLEW VUVLO
VOUT CSLEW VUVLO
ENABLE
(Top View)
MIC20X6
January 2009
M9999-012109-A
Micrel, Inc.
MIC20XX Family
MIC20XX Family Member Configuration Drawings (continued)
Adjustable Current Limit
ENABLE
VOUT CSLEW ILIMIT
VOUT CSLEW ILIMIT
ENABLE
(Top View)
MIC20X7 20X8
ENABLE
VOUT ILIMIT FAULT/
VOUT ILIMIT FAULT/
ENABLE
(Top View)
MIC20X9
January 2009
M9999-012109-A
Micrel, Inc.
MIC20XX Family
Descriptions
These signal descriptions differentiation from electrical signals components connected that pin. example, VOUT switch's output pin, while VOUT electrical signal output voltage present VOUT pin.
Descriptions
Name Type Description
ENABLE FAULT/ CSLEW VOUT VUVLO ILIMIT
Input Input Output Input Output Input Input
Supply input. This provides power both output switch switch's internal control circuitry. Ground. Switch Enable (Input): Fault status. logic this indicates switch current limiting, been shut down thermal protection circuit. This open-drain output allowing logical OR'ing multiple switches. Slew rate control. Adding small value capacitor between this slows turn-ON power FET. Switch output. load being driven switch connected this pin. Variable Under Voltage Lockout (VUVLO): Monitors input voltage through resistor divider between GND. Shuts switch voltage falls below threshold resistor divider. Previously called VUVLO. current limit threshold resistor connected from ILIMIT GND.
Signal Descriptions
Signal Name Type Description
VFAULT/ CSLEW VOUT VVUVLO_TH CLOAD IOUT ILIMIT
Input Input Output Component Output Internal Component Output Internal
Electrical signal input voltage present pin. Ground. Electrical signal input voltage present ENABLE pin. Electrical signal output voltage present FAULT/ pin. Capacitance value connected CSLEW pin. Electrical signal output voltage present VOUT pin. VUVLO internal reference threshold voltage. This voltage compared VUVLO input voltage determine switch should disabled. Reference threshold voltage typical value 250mV. Capacitance value connected parallel with load. Load capacitance. Electrical signal output current present VOUT pin. Switch's current limit. Fixed factory user adjustable.
January 2009
M9999-012109-A
Micrel, Inc.
MIC20XX Family
Absolute Maximum Ratings(1)
VIN, VOUT. -0.3V other pins -0.3V 5.5V Power Dissipation (PD) .Internally Limited Continuous Output Current.2.25A Continuous Output Current (MIC2005A) .0.9A Maximum Junction Temperature (TJ) 150°C Storage Temperature (Ts).-65°C +150°C
Operating Ratings(2)
Supply Voltage .2.5V 5.5V Continuous Output Current Range.0A 2.1A Ambient Temperature Range (TA). -40°C to+85°C Package Thermal Resistance SOT-23-5/6 (JA) MLF-6 (JA). MLF-6 (JC)
Electrical Characteristics(4)
25°C unless otherwise specified. Bold indicates -40°C +85°C limits; 1µF.
Symbol Parameter Condition Units
Switch Input Voltage Internal Supply Current except: MIC2005-X.XLYM5 MIC2005A Switch
Switch IOUT
1.5V
Switch
Internal Supply Current MIC2005-X.XLYM5
1.5V
Switch IOUT
Switch
MIC2005A-1,
Internal Supply Current MIC2005A Switch
MIC2005A-2, 1.5V
Switch
MIC2005A-1, 1.5V MIC2005A-2,
Switch OFF, VOUT ILEAK ICSLEW Output Leakage Current Enable Input Current CSLEW Input Current Power Switch Resistance RDS(ON) except MIC2005A Power Switch Resistance Only MIC2005A RDSCHG Load Discharge Resistance MIC20X4 MIC20X7 Fixed Current Limit MIC20X3 MIC20X6 Active Low; ENABLE 1.5V Active High; ENABLE VOUT 0.8VIN IOUT 100mA IOUT 100mA ISINK MIC20XX-0.5, VOUT MIC20XX-0.8, VOUT MIC20XX-1.2, VOUT
0.175
M9999-012109-A
ILIMIT
January 2009
Micrel, Inc.
MIC20XX Family
Electrical Characteristics (continued)
Symbol Parameter Condition Units
Variable Current Limit Factor MIC20X7 MIC20X9 RSET IOUT Secondary current limit MIC201X (All Kickstart parts only) Under Voltage Lock Threshold Undervoltage Lock Hysteresis Variable UVLO Threshold MIC20X6 ENABLE Input Voltage
IOUT VOUT 0.8VIN IOUT VOUT 0.8VIN IOUT 0.5A, VOUT 0.8VIN IOUT 0.2A, VOUT 0.8VIN 2.5V Rising Falling
2.25 2.15
ILIMIT_2nd UVLOTHRESHOLD UVLOHysteresis VVUVLO_TH VFAULT OTTHRESHOLD
(MAX) (MIN) 10mA Increasing Decreasing
Fault status Output Voltage Over-temperature Threshold
0.25
Characteristics
Symbol Parameter Condition Units
CLOAD 1µF, tRISE Output Turn-on rise time Delay before asserting releasing FAULT/ MIC200X tD_FAULT Delay before asserting releasing FAULT/ MIC201X tD_LIMIT Delay before current limiting MIC201X Delay before resetting Kickstart current limit delay, tD_LIMIT MIC201X tON_DLY Output Turn-on Delay current limit following current limit event. 120µF, VOUT *CSLEW Open 120µF, tOFF_DLY Output Turn-off Delay VOUT *CSLEW Open
Note: Whenever CSLEW present.
VOUT *CSLEW Open Time from current limiting FAULT/ state change Time from IOUT continuously exceeding primary current limit condition FAULT/ state change
1000
1500
tRESET
1000
1500
January 2009
M9999-012109-A
Micrel, Inc.
MIC20XX Family
Electrical Characteristics (continued)
Symbol
Parameter
Condition
Units
VESD_HB
Electro Static Discharge Voltage: Human Body Model Electro Static Discharge Voltage; Machine Model
VOUT other pins pins Machine Model
±200
VESD_MCHN
Notes: Exceeding absolute maximum rating damage device. device guaranteed function outside operating rating. Requires proper thermal mounting achieve this performance Specifications packaged product only. (MAX) maximum positive voltage applied input which will accepted device logic low. (MIN) minimum positive voltage applied input which will accepted device logic high. Devices sensitive. Handling precautions recommended. Human body model, 1.5k series with 100pF.
Timing Diagrams
tRISE tFALL
Rise Fall Times
ENABLE
tON_DLY
tOFF_DLY
VOUT
Switching Delay Times
January 2009
M9999-012109-A
Micrel, Inc.
MIC20XX Family
Typical Characteristics
SUPPLY CURRENT (µA)
Supply Current Output Enabled
25°C -40°C 85°C
SUPPLY CURRENT (µA)
Supply Current Output Disabled
-40°C LEAKAGE CURRENT (µA)
2.00 1.80 1.60 1.40 1.20 1.00 0.80 0.60 0.40 0.20
Switch Leakage Current
85°C
25°C
0.00 TEMPERATURE (°C)
ILIMIT Temperature
1.10 1.08 1.06 ILIMIT ILIMIT 1.04 1.02 1.00 0.98 0.96
2.5V
ILIMIT Temperature
1.40 1.20 1.00 0.80 0.60 0.40 0.20
2.5V
ILIMIT Temperature
1.10 1.08 1.06 ILIMIT 1.04 1.02 1.00 0.98
2.5V
(MIC20xx 1.2)
(MIC20xx 0.8)
(MIC20xx 0.5)
Note: Please note that plots overlay each
0.94 TEMPERATURE (°C)
0.00 TEMPERATURE (°C)
0.96 TEMPERATURE (°C)
2.25 THRESHOLD 2.15 2.05
UVLO Threshold Temperature
RISING (mOhm)
(mOhm)
Supply Voltage
Temperature
3.3V 2.5V
FALLING
TEMPERATURE (°C)
TEMPERATURE (°C)
January 2009
M9999-012109-A
Micrel, Inc.
MIC20XX Family
Functional Characteristics
January 2009
M9999-012109-A
Micrel, Inc.
MIC20XX Family
Functional Characteristics (continued)
January 2009
M9999-012109-A
Micrel, Inc.
MIC20XX Family
Functional Diagram
VUVLO MIC20X6 ENABLE MIC20X4 MIC20X9 FAULT/ MIC20X5 MIC20X9
VUVLO
Under Voltage Detector Control Logic Delay Timer
Current Mirror Power
Gate Control
VOUT
Thermal Sensor CSLEW MIC20X5 MIC20X8 Slew Rate Control
Load Discharge MIC20X4 MIC20X7
VREF
Current Limit Control Loop
ILIM Factory Adjusted MIC20X3 MIC20X6 ILIM User Adjustable MIC20X7 MIC20X9
Figure MIC20XX Family Functional Diagram
January 2009
M9999-012109-A
Micrel, Inc.
MIC20XX Family Kickstart operation shown below.
Functional Description
VOUT both power supply connection internal circuitry driving switch input (Source connection) power MOSFET switch. VOUT Drain connection power MOSFET supplies power load. typical circuit, current flows from VOUT toward load. Since switch bidirectional when enabled, VOUT greater than VIN, current will flow from VOUT VIN. When switch disabled, current will flow load, except small unavoidable leakage current microamps. However, should VOUT exceed more than diode drop (~0.6 while switch disabled, current will flow from output input power MOSFET's body diode. discharging CLOAD required your application, consider using MIC20X4 MIC20X7; these MIC20XX family members equipped with discharge insure complete discharge CLOAD. Current Sensing Limiting MIC20XX protects system power supply load from damage continuously monitoring current through on-chip power MOSFET. Load current monitored means current mirror parallel with power MOSFET switch. Current limiting invoked when load exceeds over-current threshold. When current limiting activated output current constrained limit value, remains this level until either load/fault removed, load's current requirement drops below limiting value, switch goes into thermal shutdown. Kickstart
2003 2013 2004 2014 2005 2015 2006 2016 2007 2017 2008 2018 2009 2019
Figure Kickstart Operation
Figure Label Key: MIC201X enabled into excessive load (slew rate limiting visible this time scale) initial current surge limited either overall circuit resistance power supply compliance, secondary current limit, whichever less. power increases internal heating (effect exaggerated emphasis). Kickstart period. Current limiting initiated. FAULT/ goes LOW. VOUT non-zero (load heavy, dead short where VOUT Limiting response will same dead shorts). Thermal shutdown followed thermal cycling. Excessive load released, normal load remains. MIC201X drops current limiting. FAULT/ delay period followed FAULT/ going HIGH. Under Voltage Lock Under voltage lock-out insures anomalous operation occurs before device's minimum input voltage UVLOTHRESHOLD which minimum, 2.25V typical, 2.5V maximum been achieved. Prior reaching this voltage, output switch (power MOSFET) circuit functions, such FAULT/ ENABLE, considered valid operative.
Only parts white boxes have Kickstart. (Not available 5-pin SOT-23 packages)
MIC201X designed allow momentary current surges (Kickstart) before onset current limiting, which permits dynamic loads, such small disk drives portable printers draw energy needed overcome inertial loads without sacrificing system safety. this respect, Kickstart parts (MIC201X) differs markedly from non-Kickstart parts (MIC200X) which immediately limit load current, potentially starving motor causing appliance stall stutter. During this delay period, typically 128ms, secondary current limit effect. load demands current excess secondary limit, MIC201X acts immediately restrict output current secondary limit duration Kickstart period. After this time MIC201X reverts normal current limit. example January 2009
M9999-012109-A
Micrel, Inc. Variable Under Voltage Lock (VUVLO)
2003 2013 2004 2014 2005 2015 2006 2016 2007 2017 2008 2018 2009 2019
MIC20XX Family Because FAULT/ open-drain must pulled HIGH with external resistor wire-OR'd with other similar outputs, sharing single pull-up resistor. FAULT/ tied pull-up voltage source which higher than VIN, greater than 5.5V. Soft-start Control Large capacitive loads create significant inrush current surges when charged through switch. this reason, MIC20XX family switches provides built-in soft-start control limit initial inrush currents. Soft-start accomplished controlling power MOSFET when ENABLE enables switch. CSLEW
2003 2013 2004 2014 2005 2015 2006 2016 2007 2017 2008 2018 2009 2019
Only parts white boxes have VUVLO.
VUVLO functions input voltage monitor when switch enabled. monitored drop voltage, indicating excessive loading supply. When less than VULVO threshold voltage (VVUVLO_TH) 32ms more, MIC20XX disables switch protect supply allow recover. After 128ms elapsed, MIC20X6 enables switch. This disable enable cycling will continue long deceases below VUVLO threshold voltage (VVUVLO_TH) which typical value 250mV. VUVLO voltage commonly established voltage divider from GND. ENABLE
2003 2013 2004 2014 2005 2015 2006 2016 2007 2017 2008 2018 2009 2019
Only parts white boxes have CSLEW pin. (Not available 5-pin SOT-23 packages)
Only parts white boxes have ENABLE pin.
ENABLE logic compatible input which activates main MOSFET switch thereby providing power VOUT pin. ENABLE either active HIGH active control signal. MIC20XX operate with logic running from supply voltages 1.8V. ENABLE driven higher than VIN, higher than 5.5V less than -0.3V. FAULT/
2003 2013 2004 2014 2005 2015 2006 2016 2007 2017 2008 2018 2009 2019
CSLEW provided increase control output voltage ramp turn-on. This input allows designers option decreasing output's slew rate (slowing voltage rise) adding external capacitance between CSLEW pins. Thermal Shutdown Thermal shutdown employed protect MIC20XX family switches from damage should temperature exceed safe operating levels. Thermal shutdown shuts output MOSFET asserts FAULT/ output temperature reaches 145°C. switch will automatically resume operation when temperature cools down 135°C. resumed operation results reheating die, another shutdown cycle will occur switch will continue cycling between states until overcurrent condition been resolved. Depending layout, package type, ambient temperature, etc., hundreds milliseconds elapse from incidence fault output MOSFET being shut off. This delay thermal time constants within system itself. event will device damaged thermal overload because temperature monitored continuously on-chip circuitry.
Only parts white boxes have FAULT/ pin.
FAULT/ N-channel open-drain output, which asserted (LOW true) when switch either begins current limiting enters thermal shutdown. FAULT/ asserts after brief delay when events occur that considered possible faults. This delay insures that FAULT/ asserted only upon valid, enduring, over-current conditions that transitory event error reports filtered out. MIC200X FAULT/ asserts after brief delay period, 32ms typical. After fault clears, FAULT/ remains asserted delay period 32ms MIC201X's FAULT/ asserts Kickstart period which 128ms typical. This masks initial current surges, such would seen motor load starting load current remains above current limit threshold after Kickstart timed out, then FAULT/ will asserted. After fault clears, FAULT/ remains asserted delay 128ms. January 2009
M9999-012109-A
Micrel, Inc.
MIC20XX Family ILIMIT IOUT measured MIC20XX's current limiting circuitry, during current limiting, designed constant current source load. load tries pull more than allotted current, VOUT drops input output voltage differential increases. When VOUT exceeds IOUT drops below ILIMIT reduce drain fault current system's power supply limit internal heating switch. When measuring IOUT important bear this voltage dependence mind, otherwise measurement data appear indicate problem when none really exists. This voltage dependence illustrated Figures Figure output current measured VOUT pulled below VIN, with test terminating when VOUT below VIN. Observe that once ILIMIT reached IOUT remains constant throughout remainder test. Figure this test repeated with VOUT exceeding When VOUT switch's current limiting circuitry responds decreasing IOUT, seen Figure this demonstration, VOUT being controlled IOUT measured quantity. real life applications VOUT determined accordance with Ohm's load limiting current.
Application Information
Setting ILIMIT MIC2009/2019's current limit user programmable controlled resistor connected between ILIMIT Ground. value this resistor determined following equation:
ILIMIT
CurrentLim itFactor(CLF) CurrentLim itFactor(V) ILIMIT
example: ILIMIT 1.25 Looking Electrical specifications will find ILIMIT
Units
sake this example, will typical value IOUT 243V. Applying equation above:
243V 194.4 1.25A
RSET
(the closest standard value)
Designers should aware that variations measured ILIMIT given RSET resistor, will occur because small differences between individual (inherent silicon processing) resulting spread ILIMIT values. example above used typical value calculate RSET. determine ILIMIT's spread using minimum maximum values calculated value RSET. ILIMIT_MIN ILIMIT_MIN 190V 0.97 260V
Figure IOUT Current Limiting
VOUT
Giving maximum ILIMIT variation over temperature ILIMIT_MIN ILIMIT_TYP ILIMIT_MAX 0.97 1.25 1.25 1.25
January 2009
M9999-012109-A
Micrel, Inc.
CSLEW
2003 2013 2004 2014 2005 2015 2006 2016 2007 2017
MIC20XX Family
2008 2018
2009 2019
Only parts white boxes have CSLEW pin. (Not available 5-pin SOT-23 packages).
CSLEW provided increase control output voltage ramp turn-on. This input allows designers option decreasing output's slew rate (slowing voltage rise) adding external capacitance between CSLEW pins. This capacitance slows rate which pass gate voltage increases thus, slows both response Enable command well VOUT's ascent final value.
Figure IOUT Current Limiting
VOUT
Figure illustrates effect CSLEW turn-on delay output rise time.
Typical Turn-on Times Capacitance External
0.014 0.012 0.01 TIME (mS) 0.008 0.006 0.004 0.002 TRISE
SLEW
This folding back ILIMIT generalized plotting ILIMIT function VOUT, shown below Figures slope VOUT between IOUT IOUT ILIMIT (where ILIMIT determined switch ILIMIT.
Normalized Output Current Output Voltage (5V)
TDELAY
NORMALIZED OUTPUT CURRENT
CSLEW (nF)
Figure
OUTPUT VOLTAGE
Figure
NORMALIZED OUTPUT CURRENT
Normalized Output Current Output Voltage (2.5V)
CSLEW's effect ILIMIT unavoidable consequence adding CSLEW capacitance reduction MIC20X5 20X8's ability quickly limit current transients surges. sufficiently large capacitance prevent both primary secondary current limits from acting time prevent damage MIC20X5 20X8 system from short circuit fault. this reason, upper limit value CSLEW 4nF. Variable Under Voltage Lock (VUVLO)
2003 2013 2004 2014 2005 2015 2006 2016 2007 2017 2008 2018 2009 2019
Only parts white boxes have VUVLO functionality.
OUTPUT VOLTAGE
Figure
Power conscious systems, such those implementing ACPI, will remain active even their power states require support external devices through both phases operation. Under these conditions, current allowed these external devices vary according system's operating state such
M9999-012109-A
January 2009
Micrel, Inc. require dual current limits their peripheral ports. MIC20X6 designed systems demanding primary current limiting levels without control signal select between current limits. better understand MIC20X6 provides this, imagine system whose main power supply supports heavy loads during normal operation, sleep mode reduced only hundred milliamps output current. addition, this system several ports which must remain active during sleep. normal operation, each port support 500mA peripheral, sleep mode their combined output current limited what power supply deliver minus whatever system itself drawing. peripheral device plugged which demands more current than available, system power supply will sag, crash. MIC20X6 prevents this monitoring both load current VIN. During normal operation, when power supply source plenty current, MIC20X6 will support load factory programmed current limit. When weaker, standby supply operation, MIC20X6 monitors will shut output should below predetermined value. This predetermined voltage user programmable selection resistor divider driving VUVLO pin. prevent false triggering VUVLO feature, MIC20X6 includes delay timer blank momentary excursions below VUVLO trip point. stays below VUVLO trip point longer than 32ms (typical), then load disengaged MIC20X6 will wait 128ms before reapplying power load. remains below VUVLO trip point, then load will powered 32ms blanking period then again disengaged. This illustrated scope plot below. remains above VUVLO trip point MIC20X6 resumes normal operation.
MIC20XX Family VUVLO Kickstart operate independently MIC2016. high current surge allowed Kickstart causes below VUVLO trip point more than 32ms, VUVLO will disengage load even though Kickstart timer timed out.
IIN_LOAD Input Supply VUVLO VOUT
Calculating VUVLO resistor divider values
Selection driven input voltage which VUVLO should into effect allowed loading input supply. VUVLO input voltage result voltage division voltage divider comprised know VVUVLO_TH then choosing trip voltage (VTRIP) know voltage divider ratio formed Then R2.is chosen such that series resistance results small IIN_LOAD. then VUVLO trip voltage relates comparator threshold resistor divider:
VVUVLO_TH VTRIP Rearranging these:
Choose that minimizes IIN_LOAD current same time less than input impedance VUVLO pin. VUVLO internally connected comparator with extremely high input impedance. recommended that exceed then calculated from equation above. example: VTRIP 4.75V supply VVUVLO_TH 250mV 750k Substituting these values into equation above: VVUVLO_TH VTRIP 0.05263 4.75 0.05263 0.25 41,667k
0.05263
Figure VUVLO Operation
41,667k
M9999-012109-A
January 2009
Micrel, Inc. this example have used nominal value VVUVLO_TH. substituting values VVUVLO_TH, VUVLO trip point window established. VUVLO comparator uses Hysteresis. This because VUVLO blanking timer prevents chattering that might otherwise occur varies about trigger point. timer reset upward crossings trip point such that must remain below trip point full 32ms period load disengagement occur. selecting VTRIP voltage designer cautioned make this value less than 2.5V. minimum 2.5V required MIC20X6's internal circuitry operate properly. VUVLO trip points below 2.5V will result erratic unpredictable operation.
Kickstart
2003 2013 2004 2014 2005 2015 2006 2016 2007 2017 2008 2018 2009 2019
MIC20XX Family
Figure Kickstart
Automatic Load Discharge
2003 2013 2004 2014 2005 2015 2006 2016 2007 2017 2008 2018 2009 2019
Only parts white boxes have Kickstart. (Not available 5-pin SOT-23 packages).
Only parts white boxes have automatic load discharge.
Kickstart allows brief current surges pass load before onset normal current limiting, which permits dynamic loads draw bursts energy without sacrificing system safety. Functionally, Kickstart forced override normal current limiting function provided switch. Kickstart period governed internal timer which allows current pass secondary current limit (ILIMIT_2nd) load 128ms then normal (primary) current limiting goes into action. During Kickstart secondary current limiting circuit monitoring output current prevent damage switch, hard short combined with robust power supply result currents many tens amperes. This secondary current limit nominally reacts immediately independently Kickstart period. Once Kickstart timer finished count primary current limiting circuit takes over holds IOUT programmed limit long excessive load persists. Once switch drops current limiting Kickstart timer initiates lock-out period 128ms such that further bursts current above primary current limit, will allowed until lock-out period expired. Kickstart over-ridden thermal protection circuit sufficient internal heating occurs, Kickstart Upon cooling, will terminated IOUT ILIMIT, ILIMIT_2nd. load still present IOUT
Automatic discharge valuable feature when desirable quickly remove charge from VOUT pin. This allows quicker power-down load. This also prevents charge from being presented device being connected VOUT pin, example, USB, 1394, PCMCIA, CableCARDTM. Automatic discharge performed shunt MOSFET from VOUT GND. When switch disabled, break before make action performed turning main power MOSFET then enabling shunt MOSFET. total resistance MOSFET internal resistances typically 126.
Supply Filtering minimum bypass capacitor positioned close pins switch both good design practice required proper operation switch. This will control supply transients ringing. Without bypass capacitor, large current surges short cause sufficient ringing (from supply lead inductance) cause erratic operation switch's control circuitry. best performance good quality, capacitors recommended, preferably ceramic. When bypassing with capacitors good practice place smaller value capacitor parallel with larger handle high frequency components line transients. Values range 0.01F 0.1F recommended. Again, good quality, capacitors should chosen.
January 2009
M9999-012109-A
Micrel, Inc.
Power Dissipation Power dissipation depends several factors such load, layout, ambient temperature, supply voltage. Calculation power dissipation accomplished following equation:
MIC20XX Family
Temperature Output Current CASE=85°C)
SOT-23
DS(ON) (IOUT
OUTPUT CURRENT
relate this junction temperature, following equation used:
Where: junction temperature, ambient temperature R(J-A) thermal resistance package normal operation switch's enough that significant heating occurs. Device heating most often caused short circuit, very heavy load, when significant portion input supply voltage appears across switch's power MOSFET. Under these conditions heat generated will exceed package PCB's ability cool device thermal limiting will invoked. Figure temperature plotted against IOUT assuming constant case temperature 85°C. plots also assume worst case 140m temperature 135°C. Under these conditions clear that SOT-23 packaged device will verge thermal shutdown, typically 140°C temperature, when operating load current 1.25A. this reason recommend using packaged switch design intending supply continuous currents more.
Figure Temperature IOUT
January 2009
M9999-012109-A
Micrel, Inc.
MIC20XX Family
Package Information
5-Pin SOT-23 (M5)
6-Pin SOT-23 (M6)
January 2009
M9999-012109-A
Micrel, Inc.
MIC20XX Family
(ML)
MICREL, INC. 2180 FORTUNE DRIVE JOSE, 95131
(408) 944-0800 (408) 474-1000 http://www.micrel.com
information furnished Micrel this data sheet believed accurate reliable. However, responsibility assumed Micrel use. Micrel reserves right change circuitry specifications time without notification customer. Micrel Products designed authorized components life support appliances, devices systems where malfunction product reasonably expected result personal injury. Life support devices systems devices systems that intended surgical implant into body support sustain life, whose failure perform reasonably expected result significant injury user. Purchaser's sale Micrel Products life support appliances, devices systems Purchaser's risk Purchaser agrees fully indemnify Micrel damages resulting from such sale. 2008 Micrel, Incorporated.
January 2009
M9999-012109-A

Fixed Adjustable Current Limiting Power Distribution Switches MIC

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