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MIC20XX Family
Fixed and Adjustable Current Limiting Power Distribution Switches
General Description
MIC20XX family of switches are current limiting, high-side power switches, designed for general purpose power distribution and control in digital televisions (DTV), printers, set top boxes (STB), PCs, PDAs, and other peripheral devices. See Functionality Table on page 6 and Pin Configuration Drawings on page 8. MIC20XX family's primary functions are current limiting and power switching. They are thermally protected and will shutdown should their internal temperature reach unsafe levels, protecting both the device and the load, under high current or fault conditions Features include fault reporting, fault blanking to eliminate noise-induced false alarms, output slew rate limiting, under voltage detection, automatic-on output, and enable pin with choice of either active low or active high enable. The FET is self-contained, with a fixed or user adjustable current limit. The MIC20XX family is ideal for any system where current limiting and power control are desired. The MIC201X (3 x 9) and MIC2019A switches offer a unique new patented feature: KickstartTM, which allows momentary high current surges up to the secondary current limit (ILIMIT_2nd) without sacrificing overall system safety. The MIC20XX family is offered, depending on the desired features, in a space saving 5-pin SOT-23, 6-pin SOT-23, (R) and 2mm x 2mm MLF packages. Datasheets and support documentation can be found on Micrel's web site at: www.micrel.com.
Features
* MIC20X3 - MIC20X9 70m typical on-resistance @ 5V * MIC2005A/20X9A 170m typical on-resistance @ 5V * Enable active high or active low * 2.5V - 5.5V operating range * Pre-set current limit values of 0.5A, 0.8A, and 1.2A* * Adjustable current limit 0.2A to 2.0A* (MIC20X7MIC20X9) * Adjustable current limit 0.1A to 0.9A* (MIC20X9A) * Under voltage lock-out (UVLO) * Variable UVLO allows adjustable UVLO thresholds* * Automatic load discharge for capacitive loads* * Soft start prevents large current inrush * Adjustable slew rate allows custom slew rates* * Automatic-on output after fault * Thermal Protection
* Available on some family members
Applications
* * * * * * * * Digital televisions (DTV) Set top boxes PDAs Printers USB / IEEE 1394 power distribution Desktop and laptop PCs Game consoles Docking stations
___________________________________________________________________________________________________________
Typical Application
5V Supply Logic Controller VIN ON/OFF OVERCURRENT/ 1F MIC2005A VIN GND EN FAULT/ VOUT VBUS 120F USB Port
Figure 1. Typical Application Circuit
Kickstart is a trademark of Micrel, Inc. MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc. CableCARD is a trademark of CableLabs. Protected by U.S. Patent No. 7,170,732
Micrel Inc. * 2180 Fortune Drive * San Jose, CA 95131 * USA * tel +1 (408) 944-0800 * fax + 1 (408) 474-1000 * http://www.micrel.com
February 2011
M9999-020311-D
Micrel, Inc.
MIC20XX Family
Ordering Information
MIC2003/2013
Part Number(1) 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 Marking(2) FD05 FD08 FD12 D05 D08 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 Yes 6-Pin 2mm x 2mm MLF(R) 5-Pin SOT-23 No 6-Pin 2mm x 2mm MLF(R) 5-Pin SOT-23 KickstartTM Package
D12 FL05
FL08 FL12 L05 L09
L12
MIC2004/2014
Part Number(1) 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: 1. All MIC20XX Family parts are RoHS compliant lead free. 2. Over/Under-bar symbol ( / _ ) may not be to scale. On the package the over/under symbol begins above/below the first character of the marking.
Marking(2) FE05 FE08 FE12 E05 E08
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
KickstartTM
Package 5-Pin SOT-23
No 6-Pin 2mm x 2mm MLF
(R)
E12 FM05
FM08 FM12 M05 M09
5-Pin SOT-23 Yes 6-Pin 2mm x 2mm MLF(R)
M12
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MIC20XX Family
Ordering Information (continued)
MIC2005
Part Number(1) MIC2005-0.5YM6 MIC2005-0.8YM6 MIC2005-1.2YM6 MIC2005-0.5YML MIC2005-0.8YML MIC2005-1.2YML Marking(2) FF05 FF08 FF12 F05 F08 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 No 6-Pin 2mm x 2mm MLF(R) 6-Pin SOT-23 KickstartTM Package
F12
MIC2005L
Part Number(1) MIC2005-0.5LYM5 MIC2005-0.8LYM5 MIC2005-1.2LYM5 Marking(2) 5LFF 8LFF 4LFF Current Limit 0.5A 0.8A 1.2A Enable Active Low Active Low Active Low No 5-Pin SOT-23 KickstartTM Package
MIC2005A
Part Number(1) MIC2005A-1YM5 MIC2005A-2YM5 MIC2005A-1YM6 MIC2005A-2YM6 Marking(2) FA51 FA52 FA53 FA54 Current Limit 0.5A 0.5A 0.5A 0.5A Enable Active High Active Low Active High Active Low No 6-Pin SOT-23 KickstartTM Package 5-Pin SOT-23
MIC2015
Part Number(1) MIC2015-0.5YM6 MIC2015-0.8YM6 MIC2015-1.2YM6 MIC2015-0.5YML MIC2015-0.8YML MIC2015-1.2YML
Notes: 1. All MIC20XX Family parts are RoHS compliant lead free. 2. Over/Under-bar symbol ( / _ ) may not be to scale. On the package the over/under symbol begins above/below the first character of the marking.
Marking(2) FN05 FN08 FN12 N05 N08
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
KickstartTM
Package 6-Pin SOT-23
Yes 6-Pin 2mm x 2mm MLF(R)
N12
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MIC20XX Family
Ordering Information (continued)
MIC2006/2016
Part Number(1) 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 Marking(2) FG05 FG08 FG12 G05 G08 G12 FP05 FP08 FP12 P05 P09 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 Yes 6-Pin 2mm x 2mm MLF
(R)
KickstartTM
Package 6-Pin SOT-23
No 6-Pin 2mm x 2mm MLF(R)
6-Pin SOT-23
P12
MIC2007/2017
Part Number(1) MIC2007YM6 MIC2007YML MIC2017YM6 MIC2017YML Marking(2) FHAA Current Limit KickstartTM No 0.2A - 2.0A Yes Package 6-Pin SOT-23 6-Pin 2mm x 2mm MLF(R) 6-Pin SOT-23 6-Pin 2mm x 2mm MLF(R)
HAA FQAA
QAA
MIC2008/2018
Part Number(1) MIC2008YM6 MIC2008YML MIC2018YM6 MIC2018YML Marking(2) FJAA JAA FRAA 0.2A - 2.0A Yes Current Limit KickstartTM No Package 6-Pin SOT-23 6-Pin 2mm x 2mm MLF(R) 6-Pin SOT-23 6-Pin 2mm x 2mm MLF(R)
RAA
MIC2009/2019
Part Number(1) MIC2009YM6 MIC2009YML MIC2019YM6 MIC2019YML
Notes: 1. All MIC20XX Family parts are RoHS compliant lead free. 2. Over/Under-bar symbol ( / _ ) may not be to scale. On the package the over/under symbol begins above/below the first character of the marking.
Marking(2) FKAA
Current Limit
KickstartTM No
Package 6-Pin SOT-23 6-Pin 2mm x 2mm MLF 6-Pin SOT-23 6-Pin 2mm x 2mm MLF
(R) (R)
KAA
FSAA SAA
0.2A - 2.0A Yes
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MIC20XX Family
Ordering Information (continued)
MIC2009A/2019A
Part Number (1) MIC2009A-1YM6 MIC2009A-2YM6 MIC2019A-1YM6 MIC2019A-2YM6
Notes: 1. All MIC20XX Family parts are RoHS compliant lead free. 2. Over/Under-bar symbol ( / _ ) may not be to scale. On the package the over/under symbol begins above/below the first character of the marking.
Marking (2) FK1 FK2 FS1 FS2
Current Limit
KickstartTM No
Enable Active High Active Low Active High Active Low
Package
0.1 A - 0.9 A Yes
6-pin SOT-23
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MIC20XX Family
MIC20XX Family Member Functionality
Part Number Normal Limiting 2003 2004 2005 2005L 2005A-1 2005A-2 2006 2007 2008 2009 2009A-1 2009A-2
Notes: 1. 2. 3. 4. 5. 6. KickstartTM provides an alternate start-up behavior; however, pin-outs are identical. KickstartTM not available. Fixed = Factory programmed current limit. Adj. = User adjustable current limit. VUVLO = Variable UVLO (Previously called DML). CSLEW not available in 5-pin package.
Pin Function I Limit ILIMIT - Fixed
(2)
KickstartTM(1) 2013 2014 2015 (1)
(1)
ENABLE High -
ENABLE Low -
CSLEW -
(6)
FAULT/ -
VUVLO(5) -
Load Discharge

(1) 2016 2017 2018 2019 2019A-1 2019A-2 Adj.
(3)
(6)

MIC20XX Family Member Pin Configuration Table, SOT Packages
Part Number Normal Limiting 2003 2004 2005 2005L 2005Axxx6 2005Axxx5 2006 2007 2008 2009 2009A
Notes: 1. 2. KickstartTM not available. Fixed = Factory programmed current limit.
Pin Number KickstartTM 2013 2014 2015
(1)
I Limit
1 VIN VIN VIN
2 GND GND GND GND GND GND GND GND GND GND GND
3 NC EN EN EN EN EN EN EN EN EN EN
4
5
6 VOUT VOUT VOUT VOUT VOUT VOUT VOUT
NC NC
FAULT/ FAULT/ FAULT/ FAULT/ VUVLO(4) ILIMIT ILIMIT FAULT/ FAULT/
VOUT VOUT
CSLEW VOUT CSLEW VOUT CSLEW CSLEW CSLEW ILIMIT ILIMIT
Fixed
(2)
VIN VIN VIN VIN VIN
(1)
(1)
2016 2017 2018 2019 2019A Adj.
(3)
VIN VIN VIN
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3. 4. ILIMIT = User adjustable current limit. VUVLO = Variable UVLO (Previously called DLM).
MIC20XX Family
MIC20XX Family Member Pin Configuration Table, MLF Packages (5)
Part Number Normal Limiting 2003 2004 2005 2006 2007 2008 2009
Notes: 1. 2. 3. 4. 5. KickstartTM not available. Fixed = Factory programmed current limit. ILIMIT = User adjustable current limit. VUVLO = Variable UVLO (Previously called DLM). Connect EP to GND.
Pin Number KickstartTM 2013 2014 2015 2016 2017 2018 2019 Adj.
(3)
I Limit
6 VIN
5 GND GND GND GND GND GND GND
4 NC EN EN EN EN EN EN
3
2
1
NC NC
FAULT/ VUVLO
(4)
NC NC
CSLEW CSLEW CSLEW CSLEW ILIMIT
VOUT VOUT
VOUT VOUT VOUT VOUT VOUT
Fixed
(2)
VIN VIN VIN VIN VIN VIN
ILIMIT ILIMIT FAULT/
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MIC20XX Family
MIC20XX Family Member Pin Configuration Drawings
Fixed Current Limit MIC20X3
VIN 1 GND 2 NC 3 4 NC 5 VOUT
5-Pin SOT-23 (M5)
6-Pin MLF(R) (ML) (Top View)
MIC20X4
VIN 1 GND 2 ENABLE 3 4 NC 5 VOUT
5-Pin SOT-23 (M5)
6-Pin MLF(R) (ML) (Top View)
MIC20X5
VIN 1 GND 2 ENABLE 3 4 FAULT/ 5 VOUT VIN 1 GND 2 ENABLE 3 6 VOUT 5 CSLEW 4 FAULT/
5-Pin SOT-23 (M5) MIC2005-X.XL
6-Pin SOT-23 (M6) MIC20X5
6-Pin MLF(R) (ML) (Top View) MIC20X5
MIC20X6
VIN 1 GND 2 ENABLE 3 6 VOUT 5 CSLEW 4 VUVLO
6-Pin SOT-23 (M6)
6-Pin MLF(R) (ML) (Top View)
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MIC20XX Family
MIC20XX Family Member Pin Configuration Drawings (continued)
Adjustable Current Limit MIC20X7/20X8
VIN 1 GND 2 ENABLE 3 6 VOUT 5 CSLEW 4 ILIMIT
6-Pin SOT-23 (M6)
6-Pin MLF(R) (ML) (Top View)
MIC20X9
VIN 1 GND 2 ENABLE 3 6 VOUT 5 ILIMIT 4 FAULT/
6-Pin SOT-23 (M6)
6-Pin MLF(R) (ML) (Top View)
MIC2005A
VIN 1 GND 2 ENABLE 3 4 FAULT/ 5 VOUT VIN 1 GND 2 ENABLE 3 6 VOUT 5 CSLEW 4 FAULT/
5-Pin SOT-23 (M5)
6-Pin SOT-23 (M6)
MIC2009A
VIN 1 GND 2 ENABLE 3 6 VOUT 5 ILIMIT 4 FAULT/
6-Pin SOT-23 (M6)
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MIC20XX Family
Descriptions
These pin and signal descriptions aid in the differentiation of a pin from electrical signals and components connected to that pin. For example, VOUT is the switch's output pin, while VOUT is the electrical signal output voltage present at the VOUT pin.
Pin Descriptions
Pin Name VIN GND EN FAULT/ CSLEW VOUT VUVLO ILIMIT EP Type Input Input Output Input Output Input Input Thermal Description Supply input. This pin provides power to both the output switch and the switch's internal control circuitry. Ground. Switch Enable (Input): Fault status. A logic LOW on this pin indicates the switch is in current limiting, or has been shut down by the thermal protection circuit. This is an open-drain output allowing logical OR'ing of multiple switches. Slew rate control. Adding a small value capacitor between this pin and VIN slows turn-ON of the power FET. Switch output. The load being driven by the switch is connected to this pin. Variable Under Voltage Lockout (VUVLO): Monitors the input voltage through a resistor divider between VIN and GND. Shuts the switch off if voltage falls below the threshold set by the resistor divider. Previously called VUVLO. Set current limit threshold via a resistor connected from ILIMIT to GND. On MLF packages connect EP to GND.
Signal Descriptions
Signal Name VIN GND VEN VFAULT/ CSLEW VOUT VVUVLO_TH CLOAD IOUT ILIMIT Type Input Input Output Component Output Internal Component Output Internal Description Electrical signal input voltage present at the VIN pin. Ground. Electrical signal input voltage present at the ENABLE pin. Electrical signal output voltage present at the FAULT/ pin. Capacitance value connected to the CSLEW pin. Electrical signal output voltage present at the VOUT pin. VUVLO internal reference threshold voltage. This voltage is compared to the VUVLO pin input voltage to determine if the switch should be disabled. Reference threshold voltage has a typical value of 250mV. Capacitance value connected in parallel with the load. Load capacitance. Electrical signal output current present at the VOUT pin. Switch's current limit. Fixed at factory or user adjustable.
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MIC20XX Family
Absolute Maximum Ratings(1)
VIN, VOUT ......................................................-0.3V to 6V All other pins.............................................-0.3V to 5.5V Power Dissipation (PD) ....................... Internally Limited Continuous Output Current All except MIC2005A / MIC20X9A................. 2.25A MIC2005A / 20X9A .......................................... 1.0A Maximum Junction Temperature (TJ).................. 150C Storage Temperature (Ts) .................. -65C to +150C Lead Temperature (Soldering 10 sec) ................ 260C
Operating Ratings(2)
Supply Voltage.............................................. 2.5V to 5.5V Continuous Output Current All except MIC2005A / MIC20X9A ........... 0A to 2.1A MIC2005A/20X9A...................................... 0A to 0.9A Ambient Temperature Range (TA) ............-40C to+85C Package Thermal Resistance(3) SOT-23-5/6 (JA) ..........................................230C/W 2mm x 2mm MLF(R) (JA) .................................90C/W 2mm x 2mm MLF(R) (JC) .................................45C/W
Electrical Characteristics(4)
VIN = 5V, TA = 25C unless otherwise specified. Bold indicates -40C to +85C limits; CIN = 1F. Symbol VIN ILEAK Parameter Switch Input Voltage Output Leakage Current(5) Switch = OFF, VOUT = 0V Active Low Enable, VEN = 1.5V Active High Enable, VEN = 0V Switch = ON Active Low Enable, VEN = 0V Active High Enable, VEN = 1.5V IIN Supply Current(5) Switch = OFF Active Low Enable, VEN = 1.5V Switch = OFF Active High Enable, VEN = 0V RDS(ON) MIC2005A ILIMIT Fixed Current Limit VOUT = 0.8 x VIN IOUT = 0.9A, VOUT = 0.8 x VIN CLF Variable Current Limit Factors IOUT = 0.5A, VOUT = 0.8 x VIN IOUT = 0.2A, VOUT = 0.8 x VIN IOUT = 0.1A, VOUT = 0.8 x VIN MIC2019A ILIMIT_2nd Secondary Current Limit VIN = 2.5V, VOUT = 0V 1 2 3 A 0.5 172 152 138 121 0.7 211 206 200 192 0.9 263 263 263 263 V A Power Switch Resistance VIN = 5V, IOUT = 100mA Condition Min 2.5 12 Typ Max 5.5 100 Units V A
MIC2005A, MIC2009A, MIC2019A 80 8 1 170 300 A A A m m
15 5 220 275
MIC2009A, MIC2019A
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MIC20XX Family
Symbol
Parameter
Condition Switch = ON Active Low Enable, VEN = 0V Active High Enable, VEN = 1.5V
Min
Typ
Max
Units
MIC2003-MIC2009, MIC2013-MIC2019, MIC2005-X.XL 80 8 1 70 330 A A A m m
IIN
Supply Current5
Switch = OFF Active Low Enable, VEN = 1.5V Switch = OFF Active High Enable, VEN = 0V
15 5 100 125
RDS(ON)
Power Switch Resistance
VIN = 5V, IOUT = 100mA
MIC2003-X.X, MIC2004-X.X, MIC2005-X.X, MIC2006-X.X, MIC2013-X.X, MIC2014-X.X, MIC2015-X.X MIC2016-X.X, MIC2005-X.XL -0.5, VOUT = 0.8 x VIN ILIMIT Fixed Current Limit -0.8, VOUT = 0.8 x VIN -1.2, VOUT = 0.8 x VIN MIC2005-0.5 ILIMIT Fixed Current Limit VOUT = 0.8 x VIN IOUT = 2.0A, VOUT = 0.8 x VIN CLF Variable Current Limit Factors IOUT = 1.0A, VOUT = 0.8 x VIN IOUT = 0.5A, VOUT = 0.8 x VIN IOUT = 0.2A, VOUT = 0.8 x VIN MIC2013, MIC2014, MIC2015, MIC2016, MIC2017, MIC2018, MIC2019 ILIMIT_2nd VUVLO_TH RDSCHG ICSLEW All Parts VEN IEN UVLOTHRESHOLD UVLOHYSTERESIS VFAULT OTTHRESHOLD ENABLE Input Voltage(6) ENABLE Input Current Under Voltage Lock Out Threshold Undervoltage Lock Out Hysteresis Fault status Output Voltage Over-temperature Threshold IOL = 10mA TJ Increasing TJ Decreasing VIL (MAX) VIH (MIN) 0V VEN 5V VIN Rising VIN Falling 2 1.9 1.5 1 2.25 2.15 0.1 0.25 145 135 0.4 5 2.5 2.4 0.5 V A V V V C Secondary Current Limit Variable UVLO Threshold Load Discharge Resistance CSLEW Input Current VIN = 5V, ISINK = 5mA 0V VOUT 0.8VIN VIN = 2.5V, VOUT = 0V 2.2 4 250 126 0.175 6 A mV A 0.5 210 190 168 144 0.7 250 243 235 225 0.9 286 293 298 299 V A 0.5 0.8 1.2 0.7 1.1 1.6 0.9 1.5 2.1 A
MIC2007, MIC2008, MIC2009, MIC2017, MIC2018, MIC2019
MIC2006, MIC2016 225 275
MIC20x4, MIC20x7 70 200
MIC20X5, MIC20X6, MIC20X7, MIC20X8
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MIC20XX Family
AC Electrical Characteristics
Symbol tRISE Parameter Output Turn-on rise time Delay before asserting or releasing FAULT/ MIC2003 - MIC2009 MIC2009A, MIC2005A Delay before asserting or releasing FAULT/ MIC2013 - MIC2019 MIC2019A Delay before current limiting tD_LIMIT MIC2013 - MIC2019 MIC2019A Delay before resetting KickstartTM current limit delay, tD_LIMIT MIC2013 - MIC2019 MIC2019A tON_DLY Output Turn-on Delay 77 128 192 ms Condition RL = 10, CLOAD = 1F, VOUT = 10% to 90% (7) CSLEW = Open Time from current limiting to FAULT/ state change Min 500 Typ 1000 Max 1500 Units s
20
32
49 ms
tD_FAULT
Time from IOUT continuously exceeding primary current limit condition to FAULT/ state change
77
128
192
tRESET
Out of current limit following a current limit event.
77
128
192
ms
RL = 43, CL = 120F, VEN = 50% to VOUT = 10% *CSLEW = Open RL = 43, CL = 120F, VEN = 50% to VOUT = 90% *CSLEW = Open
1000
1500
s
tOFF_DLY
Output Turn-off Delay
700
s
ESD(8)
Symbol VESD_HB Parameter Electro Static Discharge Voltage: Human Body Model Electro Static Discharge Voltage; Machine Model Condition VOUT and GND All other pins All pins Machine Model Min 4 kV 2 200 V Typ Max Units
VESD_MCHN
Notes:
1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. Requires proper thermal mounting to achieve this performance 4. Specifications for packaged product only. 5. Check the Ordering Information section to determine which parts are Active High or Active Low. 6. VIL(MAX) = Maximum positive voltage applied to the input which will be accepted by the device as a logic low. VIH(MAX) = Maximum positive voltage applied to the input which will be accepted by the device as a logic high. 7. Whenever CSLEW is present. 8. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
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Timing Diagrams
tRISE 90% 10% 90% 10% tFALL
Rise and Fall Times
ENABLE
50% tON_DLY
50% tOFF_DLY 90%
VOUT 10%
Switching Delay Times
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MIC20XX Family
Typical Characteristics
100 SUPPLY CURRENT (A)
Supply Current Output Enabled MIC20XX
SUPPLY CURRENT (A)
Supply Current Output Disabled (MIC20XX)
0.10 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 2.5 3.0 -40C 25C 3.5 4.0 4.5 VIN (V) 5.0 5.5 85C LEAKAGE CURRENT (A) 0.09 0.10 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 -40
Switch Leakage Current (MIC20XX)
80 85C 60 40 20 0 2.5 25C -40C
5V -15 10 35 60 TEMPERATURE (C) 85
3.0
3.5
4.0 4.5 VIN (V)
5.0
5.5
ILIMIT vs. Temperature (MIC20XX - 0.5)
1.0 0.9 5V 0.8 ILIMIT (A) ILIMIT (A) 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 -40 1.5 1.4 5V 1.3
ILIMIT vs. Temperature (MIC20XX - 0.8)
2.00 1.90 5V 1.80 ILIMIT (A) 1.70 1.60 1.50 1.40 1.30 1.20 1.10 1.00 -40
ILIMIT vs. Temperature (MIC20XX - 1.2)
1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 -40
-15 10 35 60 TEMPERATURE (C)
85
-15 10 35 60 TEMPERATURE (C)
85
-15 10 35 60 TEMPERATURE (C)
85
RDS(ON) vs. VIN
200 180 RDS(ON) (mOhm) 160 140 120 25C 100 80 60 -40C 40 20 0 2
R
200 180 160 140 120 100 80 60 40 20 0 -40
DS(ON)
vs. Temperature
CURRENT-LIMIT THRESHOLD (mA) 1200 1000 800 600 400 200 0 -40
I
LIMIT
vs. Temperature
(MIC20XX)
(MIC20XX)
(MIC20X9 - 0.9A)
RSET = 267Ohms
85C
RDS(ON) (mOhm)
2.5V
3.3V
5.0V
2.5
3
3.5 4 4.5 VIN (V)
5
5.5
-15 10 35 60 TEMPERATURE (C)
85
-15 10 35 60 TEMPERATURE (C)
85
V
160 140 VIN - VOUT (mV) 120 100 80 60 40 20 0 0
DROP
vs. Temperature
160 140 VIN - VOUT (mV) 120 100 80 60 40 20 85C 25C
V
DROP
vs. Temperature
1200 1000 85C 25C RSET (Ohms) 800 600 400 200
R
SET
vs. I
LIMIT
(MIC20XX-1.2)
VIN = 5.0V
(MIC20XX-1.2)
VIN = 3.3V
(MIC20X9)
RSET = 242.62 ILIMIT0.9538
-40C
-40C
0.2
0.4
0.6 0.8 IOUT (A)
1
1.2
0 0
0.2
0.4
0.6 0.8 IOUT (A)
1
1.2
0 0
0.2 0.4 0.6 0.8 1 ILIMIT (A)
1.2 1.4
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Typical Characteristics (cont)
Supply Current Output Enabled (MIC20XXA)
SUPPLY CURRENT (A) SUPPLY CURRENT (A) 100 90 80 70 60 50 40 30 20 10 0 2.5 3 3.5 4 4.5 VIN (V) 5 5.5 25C -40C 0.10 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 2.5 3 -40C 3.5 25C 85C 5 5.5
Supply Current Output Disabled (MIC20XXA)
LEAKAGE CURRENT (A) 0.10 0.09 0.08 0.07 0.06 0.05 0.04 0.03 0.02 0.01 0 -40
Switch Leakage Current (MIC20XXA)
85C
5V -15 10 35 60 TEMPERATURE (C) 85
4 4.5 VIN (V)
ILIMIT vs. Temperature
1.0
(MIC20X5A)
ILIMIT vs. Temperature (MIC20X9A (0.8A))
1000 R = 267Ohms 900 SET 800 700 600 500 400 300 200 100 0 -40 -15 10 35 60 TEMPERATURE (C) 2500 2000
R vs. I SET LIMIT (MIC20X9A)
RSET = 212.23 ILIMIT0.9587
0.9 5V 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 -40 -15 10 35 60 TEMPERATURE (C)
RSET (Ohms)
85
ILIMIT (A)
ILIMIT (A)
1500 1000 500 0 0
85
0.2
0.4 0.6 ILIMIT (A)
0.8
1
R
DS(ON)
vs. V
IN
R
DS(ON)
(MIC20XXA)
250 25C RDS(ON) (mOhms) 200 150 100 50 0 2.5 3 3.5 4 4.5 VIN (V) 5 5.5 -40C RDS(ON) (mOhms) 85C 250 200 150 100 50 0 -40
vs. Temperature (MIC20XXA)
2.5V 3.3V
Flag Delay vs. Temperature
40 35 5.0V 3.3V 2.5V
FLAG DELAY (ms)
85
30 25 20 15 10 5
5.0V
-15 10 35 60 TEMPERATURE (C)
0 -40
-15 10 35 60 TEMPERATURE (C)
85
V
160 140 V
DROP
vs. Temperature (MIC20XXA)
V
160 140 V
DROP
vs. Temperature (MIC20XXA)
2.3
85C
UVLO Threshold vs. Temperature
V RISING
IN
= 5.0V
IN
= 3.3V 25C
100 80 60 40 20 0 0 0.1 0.2
25C
85C
100 80 60 40 20 -40C
THRESHOLD (V)
VIN - VOUT (mV)
VIN - VOUT (mV)
120
120
2.25 2.2 2.15 2.1
V FALLING
-40C
0.3 0.4 IOUT (A)
0.5
0.6
0 0
0.1
0.2
0.3 0.4 IOUT (A)
0.5
0.6
2.05 -50
0 50 100 TEMPERATURE (C)
150
February 2011
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M9999-020311-D
Micrel, Inc.
MIC20XX Family
Functional Characteristics
February 2011
17
M9999-020311-D
Micrel, Inc.
MIC20XX Family
Functional Characteristics (Continued)
February 2011
18
M9999-020311-D
Micrel, Inc.
MIC20XX Family
Functional Characteristics (Continued)
February 2011
19
M9999-020311-D
Micrel, Inc.
MIC20XX Family
Functional Diagram
Figure 2 MIC20XX Family Functional Diagram
February 2011
20
M9999-020311-D
Micrel, Inc.
MIC20XX Family of KickstartTM operation is shown below.
Functional Description
VIN and VOUT VIN is both the power supply connection for the internal circuitry driving the switch and the input (Source connection) of the power MOSFET switch. VOUT is the Drain connection of the power MOSFET and supplies power to the load. In a typical circuit, current flows from VIN to VOUT toward the load. Since the switch is bidirectional when enabled, if VOUT is greater than VIN, current will flow from VOUT to VIN. When the switch is disabled, current will not flow to the load, except for a small unavoidable leakage current of a few microamps. However, should VOUT exceed VIN by more than a diode drop (~0.6 V), while the switch is disabled, current will flow from output to input via the power MOSFET's body diode. If discharging CLOAD is required by your application, consider using MIC20X4 or MIC20X7; these MIC20XX family members are equipped with a discharge FET to insure complete discharge of CLOAD. Current Sensing and Limiting MIC20XX protects the system power supply and load from damage by continuously monitoring current through the on-chip power MOSFET. Load current is monitored by means of a current mirror in parallel with the power MOSFET switch. Current limiting is invoked when the load exceeds the set over-current threshold. When current limiting is activated the output current is constrained to the limit value, and remains at this level until either the load/fault is removed, the load's current requirement drops below the limiting value, or the switch goes into thermal shutdown. KickstartTM
2003
2013
Figure 3. KickstartTM Operation
2004
2014
2005X
2015
2006
2016
2007
2017
2008
2018
2009X
2019X
Figure 3 Label Key: A. MIC201X is enabled into an excessive load (slew rate limiting not visible at this time scale) The initial current surge is limited by either the overall circuit resistance and power supply compliance, or the secondary current limit, whichever is less. B. RON of the power FET increases due to internal heating (effect exaggerated for emphasis). C. KickstartTM period. D. Current limiting initiated. FAULT/ goes LOW. E. VOUT is non-zero (load is heavy, but not a dead short where VOUT = 0V. Limiting response will be the same for dead shorts). F. Thermal shutdown followed by thermal cycling. G. Excessive load released, normal load remains. MIC201X drops out of current limiting. H. FAULT/ delay period followed by FAULT/ going HIGH. Under Voltage Lock Out Under voltage lock-out insures no anomalous operation occurs before the device's minimum input voltage of UVLOTHRESHOLD which is 2V minimum, 2.25V typical, and 2.5V maximum had been achieved. Prior to reaching this voltage, the output switch (power MOSFET) is OFF and no circuit functions, such as FAULT/ or ENABLE, are considered to be valid or operative.
Only parts in bold have KickstartTM. (Not available in 5-pin SOT-23 packages)
The MIC201X is designed to allow momentary current surges (KickstartTM) before the onset of current limiting, which permits dynamic loads, such as small disk drives or portable printers to draw the energy needed to overcome inertial loads without sacrificing system safety. In this respect, the KickstartTM parts (MIC201X) differs markedly from the non-KickstartTM parts (MIC200X) which immediately limit load current, potentially starving the motor and causing the appliance to stall or stutter. During this delay period, typically 128ms, a secondary current limit is in effect. If the load demands a current in excess the secondary limit, MIC201X acts immediately to restrict output current to the secondary limit for the duration of the KickstartTM period. After this time the MIC201X reverts to its normal current limit. An example February 2011 21
M9999-020311-D
Micrel, Inc. Variable Under Voltage Lock Out (VUVLO)
2003 2013 2004 2014 2005X 2015
2006 2016
MIC20XX Family with other similar outputs, sharing a single pull-up resistor. FAULT/ may be tied to a pull-up voltage source which is higher than VIN, but no greater than 5.5V. Soft-start Control Large capacitive loads can create significant inrush current surges when charged through the switch. For this reason, the MIC20XX family of switches provides a built-in soft-start control to limit the initial inrush currents. Soft-start is accomplished by controlling the power MOSFET when the ENABLE pin enables the switch. CSLEW
2003 2013 2004 2014
2005X 2015 2006 2016 2007 2017 2008 2018
2007 2017
2008 2018
2009X 2019X
Only parts in bold have VUVLO.
VUVLO functions as an input voltage monitor when the switch in enabled. The VIN pin is monitored for a drop in voltage, indicating excessive loading of the VIN supply. When VIN is less than the VULVO threshold voltage (VVUVLO_TH) for 32ms or more, the MIC20XX disables the switch to protect the supply and allow VIN to recover. After 128ms has elapsed, the MIC20X6 enables switch. This disable and enable cycling will continue as long as VIN deceases below the VUVLO threshold voltage (VVUVLO_TH) which has a typical value of 250mV. The VUVLO voltage is commonly established by a voltage divider from VIN-to-GND. ENABLE
2003 2013
2004 2014 2005X 2015 2006 2016 2007 2017 2008 2018 2009X 2019X
2009X 2019X
Only parts in bold have CSLEW pin. (Not available in 5-pin SOT-23 packages)
Only parts in bold have ENABLE pin.
The CSLEW pin is provided to increase control of the output voltage ramp at turn-on. This input allows designers the option of decreasing the output's slew rate (slowing the voltage rise) by adding an external capacitance between the CSLEW and VIN pins. Thermal Shutdown Thermal shutdown is employed to protect the MIC20XX family of switches from damage should the die temperature exceed safe operating levels. Thermal shutdown shuts off the output MOSFET and asserts the FAULT/ output if the die temperature reaches 145C. The switch will automatically resume operation when the die temperature cools down to 135C. If resumed operation results in reheating of the die, another shutdown cycle will occur and the switch will continue cycling between ON and OFF states until the overcurrent condition has been resolved. Depending on PCB layout, package type, ambient temperature, etc., hundreds of milliseconds may elapse from the incidence of a fault to the output MOSFET being shut off. This delay is due to thermal time constants within the system itself. In no event will the device be damaged due to thermal overload because die temperature is monitored continuously by on-chip circuitry.
ENABLE pin is a logic compatible input which activates the main MOSFET switch thereby providing power to the VOUT pin. ENABLE is either an active HIGH or active LOW control signal. The MIC20XX can operate with logic running from supply voltages as low as 1.5 V. ENABLE may be driven higher than VIN, but no higher than 5.5V and not less than -0.3V. FAULT/
2003 2013 2004 2014
2005X 2015
2006 2016
2007 2017
2008 2018
2009X 2019X
Only parts in bold have FAULT/ pin.
FAULT/ is an N-channel open-drain output, which is asserted (LOW true) when switch either begins current limiting or enters thermal shutdown. FAULT/ asserts after a brief delay when events occur that may be considered possible faults. This delay insures that FAULT/ is asserted only upon valid, enduring, over-current conditions and that transitory event error reports are filtered out. In MIC200X FAULT/ asserts after a brief delay period, of 32ms typical. After a fault clears, FAULT/ remains asserted for the delay period of 32ms MIC201X's FAULT/ asserts at the end of the KickstartTM period which is 128ms typical. This masks initial current surges, such as would be seen by a motor load starting up. If the load current remains above the current limit threshold after the KickstartTM has timed out, then the FAULT/ will be asserted. After a fault clears, FAULT/ remains asserted for the delay of 128ms. Because FAULT/ is an open-drain it must be pulled HIGH with an external resistor and it may be wire-OR'd February 2011 22
M9999-020311-D
Micrel, Inc.
MIC20XX Family
Application Information
IOUT RSET 1928 993 673 511 413 346 299 263 235 ILIMIT_MIN 0.063A 0.137A 0.216A 0.296A 0.379A 0.463A 0.548A 0.634A 0.722A ILIMIT_MAX 0.136A 0.265A 0.391A 0.515A 0.637A 0.759A 0.880A 1.001A 1.121A
Setting ILIMIT The MIC2009/2019's current limit is user programmable and controlled by a resistor connected between the ILIMIT pin and Ground. The value of this resistor is determined by the following equation:
ILIMIT = CurrentLim itFactor(CLF) R SET CurrentLimitFactor(CLF) ILIMIT (A)
0.1A 0.2A 0.3A 0.4A 0.5A 0.6A 0.7A 0.8A 0.9A
or
R SET =
Table 2. MIC20x9A RSET Table
For example: Set ILIMIT = 1.25 A Looking in the Electrical specifications we will find CLF at ILIMIT = 1 A.
Min Typ Max Units
IOUT 0.2A 0.3A 0.4A 0.5A 0.6A 0.7A 0.8A 0.9A 1A 1.1A 1.2A 1.3A 1.4A 1.5A
RSET 1125 765 582 470 395 341 300 268 243 222 204 189 176 165
ILIMIT_MIN 0.127A 0.202A 0.281A 0.361A 0.443A 0.526A 0.610A 0.695A 0.781A 0.868A 0.956A 1.044A 1.133A 1.222A
ILIMIT_MAX 0.267A 0.390A 0.510A 0.629A 0.746A 0.861A 0.976A 1.089A 1.202A 1.314A 1.426A 1.537A 1.647A 1.757A
190
243
293
V
Table 1. CLF at ILIMIT = 1A
For the sake of this example, we will say the typical value of CLF at an IOUT of 1A is 243V. Applying the equation above:
243V R SET ( ) = = 194.4 1.25A RSET = 196 (the closest standard 1% value) Designers should be aware that variations in the measured ILIMIT for a given RSET resistor, will occur because of small differences between individual ICs (inherent in silicon processing) resulting in a spread of ILIMIT values. In the example above we used the typical value of CLF to calculate RSET. We can determine ILIMIT's spread by using the minimum and maximum values of CLF and the calculated value of RSET. ILIMIT_MIN = ILIMIT_MAX = 190V = 0.97 A 196
Table 3. MIC20x9 RSET Table
293V = 1.5A 196 Giving us a maximum ILIMIT variation over temperature of: ILIMIT_MIN ILIMIT_TYP ILIMIT_MAX 0.97A (-22%) 1.25A 1.5A (+20%)
ILIMIT vs. IOUT Measured The MIC20XX's current limiting circuitry, during current limiting, is designed to act as a constant current source to the load. As the load tries to pull more than the allotted current, VOUT drops and the input to output voltage differential increases. When VIN - VOUT exceeds 1V, IOUT drops below ILIMIT to reduce the drain of fault current on the system's power supply and to limit internal heating of the switch. When measuring IOUT it is important to bear this voltage dependence in mind, otherwise the measurement data may appear to indicate a problem when none really exists. This voltage dependence is illustrated in Figures 4 and 5. In Figure 4, output current is measured as VOUT is pulled below VIN, with the test terminating when VOUT is 1V below VIN. Observe that once ILIMIT is reached IOUT remains constant throughout the remainder of the test. In 23
M9999-020311-D
February 2011
Micrel, Inc. Figure 5 this test is repeated but with VIN - VOUT exceeding 1V. When VIN - VOUT > 1V, switch's current limiting circuitry responds by decreasing IOUT, as can be seen in Figure 5. In this demonstration, VOUT is being controlled and IOUT is the measured quantity. In real life applications VOUT is determined in accordance with Ohm's law by the load and the limiting current.
MIC20XX Family
Normalized Output Current vs. Output Voltage (5V)
NORMALIZED OUTPUT CURRENT (A)
1.2 1.0 0.8 0.6 0.4 0.2 0
0
1 2 3 4 5 OUTPUT VOLTAGE (V)
6
Figure 6. Normalized Output Current vs. Output Voltage
NORMALIZED OUTPUT CURRENT (A)
1.2 1.0 0.8 0.6 0.4 0.2 0
Normalized Output Current vs. Output Voltage (2.5V)
Figure 4. IOUT in Current Limiting for VIN - VOUT < 1V
0
0.5 1.0 1.5 2.0 2.5 OUTPUT VOLTAGE (V)
3.0
Figure 7. Normalized Output Current vs. Output Voltage
CSLEW
2003 2013 2004 2014
2005X 2015 2006 2016 2007 2017 2008 2018
2009X 2019X
Only parts in bold have CSLEW pin. (Not available in 5-pin SOT-23 packages).
Figure 5. IOUT in Current Limiting for VIN - VOUT > 1V
This folding back of ILIMIT can be generalized by plotting ILIMIT as a function of VOUT, as shown below in Figures 6 and 7. The slope of VOUT between IOUT = 0V and IOUT = ILIMIT (where ILIMIT = 1A) is determined by RON of the switch and ILIMIT.
The CSLEW pin is provided to increase control of the output voltage ramp at turn-on. This input allows designers the option of decreasing the output's slew rate (slowing the voltage rise) by adding an external capacitance between the CSLEW and VIN pins. This capacitance slows the rate at which the pass FET gate voltage increases and thus, slows both the response to an Enable command as well as VOUT's ascent to its final value. Figure 8 illustrates effect of CSLEW on turn-on delay and output rise time.
February 2011
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M9999-020311-D
Micrel, Inc.
Typical Turn-on Times vs. External C Capacitance
14 0.014 12 0.012 10 0.01 TIME (mS) 8 0.008 6 0.006 4 0.004 2 0.002 0 0 0.5 1 1.5 0 2.5 0 3.5 0 4.5 0000203040 TRISE
SLEW
MIC20XX Family programmed current limit. When the weaker, standby supply is in operation, the MIC20X6 monitors VIN and will shut off its output should VIN dip below a predetermined value. This predetermined voltage is user programmable and set by the selection of the resistor divider driving the VUVLO pin. To prevent false triggering of the VUVLO feature, the MIC20X6 includes a delay timer to blank out momentary excursions below the VUVLO trip point. If VIN stays below the VUVLO trip point for longer than 32ms (typical), then the load is disengaged and the MIC20X6 will wait 128ms before reapplying power to the load. If VIN remains below the VUVLO trip point, then the load will be powered for the 32ms blanking period and then again disengaged. This is illustrated in the scope plot below. If VIN remains above the VUVLO trip point MIC20X6 resumes normal operation.
TON TDELAY
CSLEW (nF)
Figure 8. CSLEW vs. Turn-On, Delay and Rise TImes
CSLEW's effect on ILIMIT An unavoidable consequence of adding CSLEW capacitance is a reduction in the MIC20X5 - 20X8's ability to quickly limit current transients or surges. A sufficiently large capacitance can prevent both the primary and secondary current limits from acting in time to prevent damage to the MIC20X5 - 20X8 or the system from a short circuit fault. For this reason, the upper limit on the value of CSLEW is 4nF. Variable Under Voltage Lock Out (VUVLO)
2003 2013 2004 2014 2005X 2015
2006 2016
2007 2017
2008 2018
2009X 2019X
Only parts in bold have VUVLO pin and functionality.
Power conscious systems, such as those implementing ACPI, will remain active even in their low power states and may require the support of external devices through both phases of operation. Under these conditions, the current allowed these external devices may vary according to the system's operating state and as such require dual current limits on their peripheral ports. The MIC20X6 is designed for systems demanding two primary current limiting levels but without the use of a control signal to select between current limits. To better understand how the MIC20X6 provides this, imagine a system whose main power supply supports heavy loads during normal operation, but in sleep mode is reduced to only few hundred milliamps of output current. In addition, this system has several USB ports which must remain active during sleep. During normal operation, each port can support a 500mA peripheral, but in sleep mode their combined output current is limited to what the power supply can deliver minus whatever the system itself is drawing. If a peripheral device is plugged in which demands more current than is available, the system power supply will sag, or crash. The MIC20X6 prevents this by monitoring both the load current and VIN. During normal operation, when the power supply can source plenty of current, the MIC20X6 will support any load up to its factory February 2011 25
Figure 9. VUVLO Operation
VUVLO and KickstartTM operate independently in the MIC2016. If the high current surge allowed by KickstartTM causes VIN to dip below the VUVLO trip point for more than 32ms, VUVLO will disengage the load even though the KickstartTM timer has not timed out.
IIN_LOAD Input Supply + R1 R2 VIN VOUT MIC20X6 VUVLO +
Figure 10. VUVLO Application Circuit
Calculating VUVLO Resistor Divider Values The VUVLO feature is designed to keep the internal switch off until the voltage on the VUVLO pin is greater than 0.25V. A resistor divider network connected to the VUVLO and VIN pins is used to set the input trip voltage VTRIP, see Figure 10. The value of R2 is chosen to minimize the load on the input supply IDIV and the value of R1 sets the trip voltage VTRIP.
M9999-020311-D
Micrel, Inc. The value of R2 is calculated using:
R2 = VVUVLO IDIV
MIC20XX Family
The vale of R1 is calculated using:
R1 = R2 x
VTRIP VVUVLO
- 1

Where for both equations: VVUVLO = 0.25V When working with large value resistors, a small amount of leakage current from the VUVLO terminal can cause voltage offsets that degrade system accuracy. Therefore, the maximum recommended resistor value for R2 is 100k. Using the divider loading current IDIV of 100uA, the value of R2 can be estimated by:
R2 =
0.25 V = 2.5k 100A
Now the value of R1 can be calculated by:
4.75 V - 1 = 45k R1 = 2.5k x 0.25 V
limit (ILIMIT_2nd) to the load for 128ms and then normal (primary) current limiting goes into action. During KickstartTM a secondary current limiting circuit is monitoring output current to prevent damage to the switch, as a hard short combined with a robust power supply can result in currents of many tens of amperes. This secondary current limit is nominally set at 4A and reacts immediately and independently of the KickstartTM period. Once the KickstartTM timer has finished its count the primary current limiting circuit takes over and holds IOUT to its programmed limit for as long as the excessive load persists. Once the switch drops out of current limiting the KickstartTM timer initiates a lock-out period of 128ms such that no further bursts of current above the primary current limit, will be allowed until the lock-out period has expired. KickstartTM may be over-ridden by the thermal protection circuit and if sufficient internal heating occurs, 0A. Upon KickstartTM will be terminated and IOUT ILIMIT, not cooling, if the load is still present IOUT ILIMIT_2nd.
Where: VTRIP = 4.75V (for a 5V supply) VVUVLO = 0.25V The VUVLO comparator uses no Hysteresis. This is because the VUVLO blanking timer prevents any chattering that might otherwise occur if VIN varies about the trigger point. The timer is reset by upward crossings of the trip point such that VIN must remain below the trip point for the full 32ms period for load disengagement to occur. In selecting a VTRIP voltage, the designer is cautioned to not make this value less than 2.5V. A minimum of 2.5V is required for the MIC20X6's internal circuitry to operate properly. VUVLO trip points below 2.5V will result in erratic or unpredictable operation.
KickstartTM
2003
2013
Figure 11. KickstartTM
Automatic Load Discharge
2003
2004 2014
2005X 2015
2006 2016
2007 2017
2008 2018
2009X 2019X
2004
2014
2005X
2015
2006
2016
2007
2017
2008
2018
2009X
2019X
2013
Only parts in bold have automatic load discharge.
Only parts in bold have KickstartTM. (Not available in 5-pin SOT-23 packages).
KickstartTM allows brief current surges to pass to the load before the onset of normal current limiting, which permits dynamic loads to draw bursts of energy without sacrificing system safety. Functionally, KickstartTM is a forced override of the normal current limiting function provided by the switch. The KickstartTM period is governed by an internal timer which allows current to pass up to the secondary current
February 2011 26
Automatic discharge is a valuable feature when it is desirable to quickly remove charge from the VOUT pin. This allows for a quicker power-down of the load. This also prevents any charge from being presented to a device being connected to the VOUT pin, for example, USB, 1394, PCMCIA, and CableCARDTM. Automatic discharge is performed by a shunt MOSFET from VOUT pin to GND. When the switch is disabled, a break before make action is performed turning off the main power MOSFET and then enabling the shunt
M9999-020311-D
Micrel, Inc. MOSFET. The total resistance of the MOSFET and internal resistances is typically 126.
Supply Filtering A minimum 1F bypass capacitor positioned close to the VIN and GND pins of the switch is both good design practice and required for proper operation of the switch. This will control supply transients and ringing. Without a bypass capacitor, large current surges or a short may cause sufficient ringing on VIN (from supply lead inductance) to cause erratic operation of the switch's control circuitry. For best performance good quality, low ESR capacitors are recommended, preferably ceramic. When bypassing with capacitors of 10F and up, it is good practice to place a smaller value capacitor in parallel with the larger to handle the high frequency components of any line transients. Values in the range of 0.01F to 0.1F are recommended. Again, good quality, low ESR capacitors should be chosen. Power Dissipation Power dissipation depends on several factors such as the load, PCB layout, ambient temperature, and supply voltage. Calculation of power dissipation can be accomplished by the following equation:
MIC20XX Family assuming a constant case temperature of 85C. The plots also assume a worst case RON of 140m at a die temperature of 135C. Under these conditions it is clear that an SOT-23 packaged device will be on the verge of thermal shutdown, typically 140C die temperature, when operating at a load current of 1.25A. For this reason we recommend using MLF(R) packaged switches for any design intending to supply continuous currents of 1A or more.
Die Temperature vs. Output Current (T CASE =85C)
160 140 120 100
SOT-23 MLF
80 60 40 20 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 OUTPUT CURRENT (A)
Figure 12. Die Temperature vs. IOUT
PD = R DS(ON) x (IOUT )
2
To relate this to junction temperature, the following equation can be used:
TJ = PD x R ( J- A ) + TA
Where: TJ = junction temperature, TA = ambient temperature R(J-A) is the thermal resistance of the package In normal operation the switch's RON is low enough that no significant I2R heating occurs. Device heating is most often caused by a short circuit, or very heavy load, when a significant portion of the input supply voltage appears across the switch's power MOSFET. Under these conditions the heat generated will exceed the package and PCB's ability to cool the device and thermal limiting will be invoked. In Figure 12 die temperature is plotted against IOUT
February 2011
27
M9999-020311-D
Micrel, Inc.
MIC20XX Family
Package Information
5-Pin SOT-23 (M5)
6-Pin SOT-23 (M6)
February 2011
28
M9999-020311-D
Micrel, Inc.
MIC20XX Family
6 Pin 2mm x 2mm MLF(R) (ML)
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
Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry, specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Micrel's terms and conditions of sale for such products, Micrel assumes no liability whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. 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 February 2011 sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser's own risk and Purchaser9-020311-D 29 M999 agrees to fully indemnify Micrel for any damages resulting from such use or sale. (c) 2009 Micrel, Incorporated.

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