MIC20XX Family Fixed and Adjustable Current Limiting Power Distribution Switches General Description Features 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: Kickstart™, 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, ® and 2mm x 2mm MLF packages. Datasheets and support documentation can be found on Micrel’s web site at: www.micrel.com. • MIC20X3 – MIC20X9 70mΩ typical on-resistance @ 5V • MIC2005A/20X9A 170mΩ 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 MIC2005A Logic Controller VIN VOUT 120µF GND VIN ON/OFF OVERCURRENT/ 1µF EN VBUS USB Port FAULT/ 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) Marking(2) Current Limit MIC2003-0.5YM5 FD05 0.5A MIC2003-0.8YM5 FD08 0.8A MIC2003-1.2YM5 FD12 1.2A MIC2003-0.5YML D05 0.5A MIC2003-0.8YML D08 0.8A MIC2003-1.2YML 1.2A MIC2013-0.5YM5 D12 FL05 MIC2013-0.8YM5 FL08 0.8A MIC2013-1.2YM5 Kickstart™ Package 5-Pin SOT-23 No 6-Pin 2mm x 2mm MLF® 0.5A FL12 1.2A MIC2013-0.5YML L05 0.5A MIC2013-0.8YML L09 0.8A MIC2013-1.2YML L12 1.2A 5-Pin SOT-23 Yes 6-Pin 2mm x 2mm MLF® MIC2004/2014 Part Number(1) Marking(2) Current Limit MIC2004-0.5YM5 FE05 0.5A MIC2004-0.8YM5 FE08 0.8A MIC2004-1.2YM5 FE12 1.2A MIC2004-0.5YML E05 0.5A MIC2004-0.8YML E08 0.8A MIC2004-1.2YML 1.2A MIC2014-0.5YM5 E12 FM05 MIC2014-0.8YM5 FM08 0.8A MIC2014-1.2YM5 FM12 1.2A MIC2014-0.5YML M05 0.5A MIC2014-0.8YML M09 0.8A MIC2014-1.2YML M12 1.2A Kickstart™ Package 5-Pin SOT-23 No 6-Pin 2mm x 2mm MLF ® 0.5A 5-Pin SOT-23 Yes 6-Pin 2mm x 2mm MLF® 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. February 2011 2 M9999-020311-D Micrel, Inc. MIC20xx Family Ordering Information (continued) MIC2005 Part Number(1) Marking(2) Current Limit Enable MIC2005-0.5YM6 FF05 0.5A Active High MIC2005-0.8YM6 FF08 0.8A Active High MIC2005-1.2YM6 FF12 1.2A Active High MIC2005-0.5YML F05 0.5A Active High MIC2005-0.8YML F08 0.8A Active High MIC2005-1.2YML F12 1.2A Active High Kickstart™ Package 6-Pin SOT-23 No 6-Pin 2mm x 2mm MLF® MIC2005L Part Number(1) Marking(2) Current Limit Enable MIC2005-0.5LYM5 5LFF 0.5A Active Low MIC2005-0.8LYM5 8LFF 0.8A Active Low MIC2005-1.2LYM5 4LFF 1.2A Active Low Kickstart™ No Package 5-Pin SOT-23 MIC2005A Part Number(1) Marking(2) Current Limit Enable MIC2005A-1YM5 FA51 0.5A Active High MIC2005A-2YM5 FA52 0.5A Active Low MIC2005A-1YM6 FA53 0.5A Active High MIC2005A-2YM6 FA54 0.5A Active Low Kickstart™ Package 5-Pin SOT-23 No 6-Pin SOT-23 MIC2015 Part Number(1) Marking(2) Current Limit Enable MIC2015-0.5YM6 FN05 0.5A Active High MIC2015-0.8YM6 FN08 0.8A Active High MIC2015-1.2YM6 FN12 1.2A Active High MIC2015-0.5YML N05 0.5A Active High MIC2015-0.8YML N08 0.8A Active High MIC2015-1.2YML N12 1.2A Active High Kickstart™ Package 6-Pin SOT-23 Yes 6-Pin 2mm x 2mm MLF® 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. February 2011 3 M9999-020311-D Micrel, Inc. MIC20xx Family Ordering Information (continued) MIC2006/2016 Part Number(1) Marking(2) Current Limit MIC2006-0.5YM6 FG05 0.5A MIC2006-0.8YM6 FG08 0.8A MIC2006-1.2YM6 FG12 1.2A MIC2006-0.5YML G05 0.5A MIC2006-0.8YML G08 0.8A MIC2006-1.2YML G12 1.2A MIC2016-0.5YM6 FP05 0.5A MIC2016-0.8YM6 FP08 0.8A MIC2016-1.2YM6 FP12 1.2A MIC2016-0.5YML P05 0.5A MIC2016-0.8YML P09 0.8A MIC2016-1.2YML P12 1.2A Kickstart™ Package 6-Pin SOT-23 No 6-Pin 2mm x 2mm MLF® 6-Pin SOT-23 Yes 6-Pin 2mm x 2mm MLF ® MIC2007/2017 Part Number(1) Marking(2) MIC2007YM6 FHAA MIC2007YML MIC2017YM6 HAA FQAA MIC2017YML QAA Current Limit Kickstart™ No 0.2A – 2.0A Yes Package 6-Pin SOT-23 6-Pin 2mm x 2mm MLF® 6-Pin SOT-23 6-Pin 2mm x 2mm MLF® MIC2008/2018 Part Number(1) Marking(2) MIC2008YM6 FJAA MIC2008YML JAA MIC2018YM6 FRAA MIC2018YML RAA Current Limit Kickstart™ No 0.2A – 2.0A Yes Package 6-Pin SOT-23 6-Pin 2mm x 2mm MLF® 6-Pin SOT-23 6-Pin 2mm x 2mm MLF® MIC2009/2019 Part Number(1) Marking(2) MIC2009YM6 FKAA MIC2009YML KAA MIC2019YM6 FSAA MIC2019YML SAA Current Limit Kickstart™ No 0.2A – 2.0A Yes Package 6-Pin SOT-23 6-Pin 2mm x 2mm MLF ® 6-Pin SOT-23 6-Pin 2mm x 2mm MLF ® 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. February 2011 4 M9999-020311-D Micrel, Inc. MIC20xx Family Ordering Information (continued) MIC2009A/2019A Part Number (1) Marking (2) MIC2009A-1YM6 FK1 MIC2009A-2YM6 FK2 MIC2019A-1YM6 FS1 MIC2019A-2YM6 FS2 Current Limit Kickstart™ No 0.1 A – 0.9 A Yes Enable Package Active High Active Low Active High 6-pin SOT-23 Active Low 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. February 2011 5 M9999-020311-D Micrel, Inc. MIC20xx Family MIC20XX Family Member Functionality Part Number Normal Limiting Pin Function Kickstart™(1) I Limit ILIMIT ENABLE High ENABLE Low CSLEW FAULT/ VUVLO(5) Load Discharge 2003 2013 – – – – – – ─ 2004 2014 ─ ▲ ─ ─ ─ ─ ▲ 2005 2015 ─ ▲ ─ ▲ ▲ ─ ─ 2005L ─ (1) ─ ─ ▲ ─ Fixed (2) ▲ ─ ─ ─ ─ (6) ▲ ─ ─ ─ ▲ ─ (6) ▲ ─ ─ ─ ▲ ─ ▲ ─ ▲ ─ 2017 ▲ ▲ ─ ▲ ─ ─ ▲ 2008 2018 ▲ ▲ ─ ▲ ─ ─ ─ 2009 2019 ▲ ▲ ─ ─ ▲ ─ ─ 2009A-1 2019A-1 ▲ ▲ ─ ─ ▲ ─ ─ 2009A-2 2019A-2 ▲ ─ ▲ ─ ▲ ─ ─ 2005A-1 ─ (1) ─ ▲ 2005A-2 ─ (1) ─ 2006 2016 2007 Adj. (3) Notes: 1. Kickstart™ provides an alternate start-up behavior; however, pin-outs are identical. 2. Kickstart™ not available. 3. Fixed = Factory programmed current limit. 4. Adj. = User adjustable current limit. 5. VUVLO = Variable UVLO (Previously called DML). 6. CSLEW not available in 5-pin package. MIC20XX Family Member Pin Configuration Table, SOT Packages Part Number Pin Number Normal Limiting Kickstart™ 2003 1 2 3 4 5 6 2013 VIN GND NC NC VOUT ─ 2004 2014 VIN GND EN NC VOUT ─ 2005 2015 VIN GND EN FAULT/ CSLEW VOUT VIN GND EN FAULT/ VOUT ─ 2005L ─ (1) I Limit (2) Fixed 2005Axxx6 ─ (1) VIN GND EN FAULT/ CSLEW VOUT 2005Axxx5 (1) VIN GND EN FAULT/ VOUT ─ ─ 2006 2016 VIN GND EN VUVLO(4) CSLEW VOUT 2007 2017 VIN GND EN ILIMIT CSLEW VOUT 2008 2018 VIN GND EN ILIMIT CSLEW VOUT 2009 2019 VIN GND EN FAULT/ ILIMIT VOUT 2009A 2019A VIN GND EN FAULT/ ILIMIT VOUT Adj. (3) Notes: 1. Kickstart™ not available. 2. Fixed = Factory programmed current limit. February 2011 6 M9999-020311-D Micrel, Inc. MIC20xx Family 3. ILIMIT = User adjustable current limit. 4. VUVLO = Variable UVLO (Previously called DLM). MIC20XX Family Member Pin Configuration Table, MLF Packages (5) Part Number Pin Number Normal Limiting Kickstart™ 2003 2013 2004 2014 2005 2015 2006 2016 2007 2017 2008 2018 2009 2019 I Limit (2) Fixed Adj. (3) 6 5 4 3 2 1 VIN GND NC NC NC VOUT VIN GND EN NC NC VOUT VIN GND EN FAULT/ CSLEW VOUT CSLEW VOUT (4) VIN GND EN VUVLO VIN GND EN ILIMIT CSLEW VOUT VIN GND EN ILIMIT CSLEW VOUT VIN GND EN FAULT/ ILIMIT VOUT Notes: 1. Kickstart™ not available. 2. Fixed = Factory programmed current limit. 3. ILIMIT = User adjustable current limit. 4. VUVLO = Variable UVLO (Previously called DLM). 5. Connect EP to GND. February 2011 7 M9999-020311-D Micrel, Inc. MIC20xx Family MIC20XX Family Member Pin Configuration Drawings Fixed Current Limit MIC20X3 VIN 1 5 VOUT GND 2 NC 3 4 NC 6-Pin MLF® (ML) (Top View) 5-Pin SOT-23 (M5) MIC20X4 VIN 1 5 VOUT GND 2 ENABLE 3 4 NC 6-Pin MLF® (ML) (Top View) 5-Pin SOT-23 (M5) MIC20X5 VIN 1 VIN 1 5 VOUT GND 2 ENABLE 3 4 FAULT/ 5-Pin SOT-23 (M5) MIC2005-X.XL 6 VOUT GND 2 5 CSLEW ENABLE 3 4 FAULT/ 6-Pin SOT-23 (M6) MIC20X5 6-Pin MLF® (ML) (Top View) MIC20X5 MIC20X6 VIN 1 6 VOUT GND 2 5 CSLEW ENABLE 3 4 VUVLO 6-Pin MLF® (ML) (Top View) 6-Pin SOT-23 (M6) February 2011 8 M9999-020311-D Micrel, Inc. 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 MLF® (ML) (Top View) 6-Pin SOT-23 (M6) MIC20X9 VIN 1 6 VOUT GND 2 5 ILIMIT ENABLE 3 4 FAULT/ 6-Pin MLF® (ML) (Top View) 6-Pin SOT-23 (M6) MIC2005A VIN 1 VIN 1 5 VOUT GND 2 ENABLE 3 4 FAULT/ 5-Pin SOT-23 (M5) 6 VOUT GND 2 5 CSLEW ENABLE 3 4 FAULT/ 6-Pin SOT-23 (M6) MIC2009A VIN 1 6 VOUT GND 2 5 ILIMIT ENABLE 3 4 FAULT/ 6-Pin SOT-23 (M6) February 2011 9 M9999-020311-D Micrel, Inc. 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 Type Description VIN Input Supply input. This pin provides power to both the output switch and the switch’s internal control circuitry. GND ─ EN Input 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. FAULT/ Output CSLEW Input VOUT Output VUVLO Input 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. ILIMIT Input Set current limit threshold via a resistor connected from ILIMIT to GND. EP Thermal 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. On MLF packages connect EP to GND. Signal Descriptions Signal Name Type Description VIN Input Electrical signal input voltage present at the VIN pin. GND ─ Ground. VEN Input Electrical signal input voltage present at the ENABLE pin. VFAULT/ Output Electrical signal output voltage present at the FAULT/ pin. CSLEW Component VOUT Output Electrical signal output voltage present at the VOUT pin. VVUVLO_TH Internal 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. CLOAD Component IOUT Output Electrical signal output current present at the VOUT pin. ILIMIT Internal Switch’s current limit. Fixed at factory or user adjustable. February 2011 Capacitance value connected to the CSLEW pin. Capacitance value connected in parallel with the load. Load capacitance. 10 M9999-020311-D Micrel, Inc. MIC20xx Family Absolute Maximum Ratings(1) Operating Ratings(2) 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).................. 150°C Storage Temperature (Ts) .................. –65°C to +150°C Lead Temperature (Soldering 10 sec) ................ 260°C 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) ............–40°C to+85°C Package Thermal Resistance(3) SOT-23-5/6 (θJA) ..........................................230ºC/W 2mm × 2mm MLF® (θJA) .................................90ºC/W 2mm × 2mm MLF® (θJC) .................................45ºC/W Electrical Characteristics(4) VIN = 5V, TA = 25°C unless otherwise specified. Bold indicates –40°C to +85°C limits; CIN = 1µF. Symbol Parameter VIN Switch Input Voltage ILEAK Output Leakage Current(5) Condition Min Typ 2.5 Max Units 5.5 V Switch = OFF, VOUT = 0V Active Low Enable, VEN = 1.5V Active High Enable, VEN = 0V 12 100 µA Switch = ON Active Low Enable, VEN = 0V Active High Enable, VEN = 1.5V 80 300 µA Switch = OFF Active Low Enable, VEN = 1.5V 8 15 µA Switch = OFF Active High Enable, VEN = 0V 1 5 µA 170 220 mΩ 275 mΩ A MIC2005A, MIC2009A, MIC2019A IIN RDS(ON) Supply Current(5) Power Switch Resistance VIN = 5V, IOUT = 100mA MIC2005A ILIMIT Fixed Current Limit VOUT = 0.8 × VIN 0.5 0.7 0.9 IOUT = 0.9A, VOUT = 0.8 × VIN 172 211 263 IOUT = 0.5A, VOUT = 0.8 × VIN 152 206 263 IOUT = 0.2A, VOUT = 0.8 × VIN 138 200 263 IOUT = 0.1A, VOUT = 0.8 × VIN 121 192 263 1 2 3 MIC2009A, MIC2019A CLF Variable Current Limit Factors V MIC2019A ILIMIT_2nd Secondary Current Limit February 2011 VIN = 2.5V, VOUT = 0V 11 A M9999-020311-D Micrel, Inc. Symbol MIC20xx Family Parameter Condition Min Typ Max Units Switch = ON Active Low Enable, VEN = 0V Active High Enable, VEN = 1.5V 80 330 µA Switch = OFF Active Low Enable, VEN = 1.5V 8 15 µA Switch = OFF Active High Enable, VEN = 0V 1 5 µA 70 100 mΩ 125 mΩ MIC2003-MIC2009, MIC2013-MIC2019, MIC2005-X.XL IIN RDS(ON) Supply Current5 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 ILIMIT Fixed Current Limit -0.5, VOUT = 0.8 x VIN 0.5 0.7 0.9 -0.8, VOUT = 0.8 x VIN 0.8 1.1 1.5 -1.2, VOUT = 0.8 x VIN 1.2 1.6 2.1 VOUT = 0.8 x VIN 0.5 0.7 0.9 IOUT = 2.0A, VOUT = 0.8 x VIN 210 250 286 IOUT = 1.0A, VOUT = 0.8 x VIN 190 243 293 IOUT = 0.5A, VOUT = 0.8 x VIN 168 235 298 IOUT = 0.2A, VOUT = 0.8 x VIN 144 225 299 2.2 4 6 A 225 250 275 mV 70 126 200 Ω A MIC2005-0.5 ILIMIT Fixed Current Limit A MIC2007, MIC2008, MIC2009, MIC2017, MIC2018, MIC2019 CLF Variable Current Limit Factors V MIC2013, MIC2014, MIC2015, MIC2016, MIC2017, MIC2018, MIC2019 ILIMIT_2nd Secondary Current Limit VIN = 2.5V, VOUT = 0V MIC2006, MIC2016 VUVLO_TH Variable UVLO Threshold MIC20x4, MIC20x7 RDSCHG Load Discharge Resistance VIN = 5V, ISINK = 5mA MIC20X5, MIC20X6, MIC20X7, MIC20X8 ICSLEW CSLEW Input Current 0V ≤ VOUT ≤ 0.8VIN 0.175 µA All Parts VIL (MAX) VEN ENABLE Input Voltage(6) IEN ENABLE Input Current 0V ≤ VEN ≤ 5V UVLOTHRESHOLD Under Voltage Lock Out Threshold VIN Rising VIN Falling UVLOHYSTERESIS Undervoltage Lock Out Hysteresis VFAULT Fault status Output Voltage OTTHRESHOLD Over-temperature Threshold February 2011 0.5 VIH (MIN) 1.5 1 5 2 2.25 2.5 1.9 2.15 2.4 0.1 IOL = 10mA 0.25 TJ Increasing 145 TJ Decreasing 135 12 V µA V V 0.4 V °C M9999-020311-D Micrel, Inc. MIC20xx Family AC Electrical Characteristics Symbol Parameter Condition Min Typ Max Units tRISE Output Turn-on rise time RL = 10Ω, CLOAD = 1µF, VOUT = 10% to 90% (7) CSLEW = Open 500 1000 1500 µs Time from current limiting to FAULT/ state change 20 32 49 Delay before asserting or releasing FAULT/ tD_FAULT MIC2003 – MIC2009 MIC2009A, MIC2005A Delay before asserting or releasing FAULT/ MIC2013 – MIC2019 MIC2019A ms Time from IOUT continuously exceeding primary current limit condition to FAULT/ state change 77 128 192 77 128 192 ms 77 128 192 ms 1000 1500 µs 700 µs Max Units Delay before current limiting tD_LIMIT tRESET MIC2013 – MIC2019 MIC2019A Delay before resetting Kickstart™ current limit delay, tD_LIMIT MIC2013 – MIC2019 MIC2019A Out of current limit following a current limit event. tON_DLY Output Turn-on Delay RL = 43Ω, CL = 120µF, VEN = 50% to VOUT = 10% *CSLEW = Open tOFF_DLY Output Turn-off Delay RL = 43Ω, CL = 120µF, VEN = 50% to VOUT = 90% *CSLEW = Open ESD(8) Symbol Parameter VESD_HB Electro Static Discharge Voltage: Human Body Model VESD_MCHN Electro Static Discharge Voltage; Machine Model Condition Min VOUT and GND ±4 All other pins ±2 Typ kV All pins ±200 Machine Model V 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. February 2011 13 M9999-020311-D Micrel, Inc. MIC20xx Family Timing Diagrams tRISE tFALL 90% 90% 10% 10% Rise and Fall Times ENABLE 50% 50% tON_DLY tOFF_DLY 90% VOUT 10% Switching Delay Times February 2011 14 M9999-020311-D Micrel, Inc. MIC20xx Family Typical Characteristics Supply Current Output Disabled (MIC20XX) SUPPLY CURRENT (µA) 80 85°C 60 40 25°C -40°C 20 0 2.5 3.0 3.5 4.0 4.5 VIN (V) 5.0 0.10 0.10 0.09 0.09 0.08 0.07 0.06 0.05 0.04 0.03 85°C 0.02 -40°C 25°C 0.01 0 2.5 5.5 3.0 0.05 0.04 0.03 0.02 5V 0.01 0 -40 5.5 -15 10 35 60 TEMPERATURE (°C) 0.7 0.6 0.5 1.2 1.1 1.0 1.70 1.60 1.50 0.9 0.8 0.7 0.6 0.5 -40 85 R (MIC20XX) 160 140 120 25°C 100 85°C 80 60 -40°C 40 2.5 V 3 DROP 160 140 3.5 4 4.5 VIN (V) 5 5.5 160 140 120 85°C 25°C 80 60 -40°C 40 20 0 0 3.3V -15 10 35 60 TEMPERATURE (°C) DROP VIN = 5.0V LIMIT 5.0V V (MIC20XX-1.2) 100 2.5V 85 (MIC20XX-1.2) February 2011 0.4 0.6 0.8 IOUT (A) 1 1.2 85°C 25°C 80 60 -40°C 40 0 0 800 600 400 200 0 -40 1000 100 (MIC20X9 - 0.9A) RSET = 267Ohms 1000 1200 VIN = 3.3V 85 vs. Temperature -15 10 35 60 TEMPERATURE (°C) R SET 85 vs. I LIMIT (MIC20X9) RSET = 242.62 ILIMIT0.9538 800 600 400 200 20 0.2 1200 vs. Temperature 120 -15 10 35 60 TEMPERATURE (°C) I (MIC20XX) 180 160 140 120 100 80 60 40 20 0 -40 vs. Temperature VIN – VOUT (mV) 20 0 2 85 vs. Temperature DS(ON) 200 RDS(ON) (mOhm) 200 180 -15 10 35 60 TEMPERATURE (°C) 1.40 1.30 1.20 1.10 1.00 -40 CURRENT-LIMIT THRESHOLD (mA) -15 10 35 60 TEMPERATURE (°C) ILIMIT (A) 2.00 1.90 5V 1.80 0.4 0.3 0.2 85 ILIMIT vs. Temperature (MIC20XX - 1.2) 1.5 1.4 5V 1.3 RDS(ON) vs. VIN RDS(ON) (mOhm) 5.0 0.06 1.0 0.9 5V 0.8 0.1 0 -40 VIN – VOUT (mV) 4.0 4.5 VIN (V) 0.08 0.07 ILIMIT vs. Temperature (MIC20XX - 0.8) ILIMIT (A) ILIMIT (A) ILIMIT vs. Temperature (MIC20XX - 0.5) 3.5 RSET (Ohms) SUPPLY CURRENT (µA) 100 Switch Leakage Current (MIC20XX) LEAKAGE CURRENT (µA) Supply Current Output Enabled MIC20XX 0.2 0.4 0.6 0.8 IOUT (A) 15 1 1.2 0 0 0.2 0.4 0.6 0.8 1 ILIMIT (A) 1.2 1.4 M9999-020311-D Micrel, Inc. MIC20xx Family Typical Characteristics (cont) 85°C 40 30 20 10 0 2.5 3 3.5 4 4.5 VIN (V) 5 0.06 0.05 0.04 0.03 0.02 0.01 -40°C 0 2.5 5.5 3 (MIC20X5A) ILIMIT (A) ILIMIT (A) DS(ON) 85 R IN RDS(ON) (mOhms) 85°C 150 -40°C 50 0 2.5 3 V 3.5 4 4.5 VIN (V) 5 2.5V 5.5 vs. Temperature (MIC20XXA) V IN 120 25°C 100 85°C 80 60 -40°C 40 20 0 0 February 2011 0.2 0.3 0.4 IOUT (A) 0.5 0 0 0.6 0.4 0.6 ILIMIT (A) 0.8 1 40 3.3V 35 5.0V 30 25 3.3V 2.5V 20 15 10 5 -15 10 35 60 TEMPERATURE (°C) 0 -40 85 vs. Temperature (MIC20XXA) V IN 2.3 = 3.3V 120 25°C 85°C 100 80 60 -40°C 40 0 0 0.2 Flag Delay vs. Temperature 2.25 -15 10 35 60 TEMPERATURE (°C) 85 UVLO Threshold vs. Temperature V RISING 2.2 2.15 V FALLING 2.1 20 0.1 1000 DROP 140 212.23 ILIMIT0.9587 1500 85 50 160 85 500 100 V = 5.0V RSET = 2000 5.0V 150 0 -40 VIN - VOUT (mV) VIN - VOUT (mV) 140 -15 10 35 60 TEMPERATURE (°C) 2500 200 DROP 160 5V R vs. I SET LIMIT (MIC20X9A) vs. Temperature (MIC20XXA) 250 RDS(ON) (mOhms) 250 100 0.02 0.01 DS(ON) (MIC20XXA) 200 0.04 0.03 5.5 R = 267Ohms 900 SET 800 700 600 500 400 300 200 100 0 -40 -15 10 35 60 TEMPERATURE (°C) vs. V 25°C 5 0.06 0.05 0 -40 1000 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) R 4 4.5 VIN (V) 85°C 0.08 0.07 ILIMIT vs. Temperature (MIC20X9A (0.8A)) ILIMIT vs. Temperature 1.0 3.5 25°C RSET (Ohms) 25°C 60 50 0.08 0.07 0.10 0.09 FLAG DELAY (ms) 80 70 0.10 0.09 LEAKAGE CURRENT (µA) -40°C Switch Leakage Current (MIC20XXA) THRESHOLD (V) 100 90 Supply Current Output Disabled (MIC20XXA) SUPPLY CURRENT (µA) SUPPLY CURRENT (µA) Supply Current Output Enabled (MIC20XXA) 0.1 0.2 0.3 0.4 IOUT (A) 16 0.5 0.6 2.05 -50 0 50 100 TEMPERATURE (°C) 150 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 Kickstart™ 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. Figure 3. Kickstart™ Operation 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. Kickstart™ 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. 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. Kickstart™ 2003 2004 2005X 2006 2007 2008 2009X 2013 2014 2015 2016 2017 2018 2019X Only parts in bold have Kickstart™. (Not available in 5-pin SOT-23 packages) 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. The MIC201X is designed to allow momentary current surges (Kickstart™) 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 Kickstart™ parts (MIC201X) differs markedly from the non-Kickstart™ 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 Kickstart™ period. After this time the MIC201X reverts to its normal current limit. An example February 2011 21 M9999-020311-D Micrel, Inc. 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. Variable Under Voltage Lock Out (VUVLO) 2003 2004 2005X 2006 2007 2008 2009X 2013 2014 2015 2016 2017 2018 2019X 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. 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. CSLEW 2004 2005X 2006 2007 2008 2009X 2013 2014 2015 2016 2017 2018 2019X 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. 2005X 2006 2007 2008 2009X 2013 2014 2015 2016 2017 2018 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 Kickstart™ 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 Kickstart™ 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 2006 2007 2008 2009X 2013 2014 2015 2016 2017 2018 2019X 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 145°C. The switch will automatically resume operation when the die temperature cools down to 135°C. 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. FAULT/ 2004 2005X 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. Only parts in bold have ENABLE pin. 2003 2004 Only parts in bold have CSLEW pin. (Not available in 5-pin SOT-23 packages) ENABLE 2003 2003 22 M9999-020311-D Micrel, Inc. MIC20xx Family Application Information 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 or R SET = CurrentLimitFactor(CLF) ILIMIT (A) IOUT RSET ILIMIT_MIN ILIMIT_MAX 0.1A 1928Ω 0.063A 0.136A 0.2A 993Ω 0.137A 0.265A 0.3A 673Ω 0.216A 0.391A 0.4A 511Ω 0.296A 0.515A 0.5A 413Ω 0.379A 0.637A 0.6A 346Ω 0.463A 0.759A 0.7A 299Ω 0.548A 0.880A 0.8A 263Ω 0.634A 1.001A 0.9A 235Ω 0.722A 1.121A 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. IOUT RSET ILIMIT_MIN ILIMIT_MAX 0.2A 1125Ω 0.127A 0.267A 0.3A 765Ω 0.202A 0.390A 0.4A 582Ω 0.281A 0.510A 0.5A 470Ω 0.361A 0.629A Table 1. CLF at ILIMIT = 1A 0.6A 395Ω 0.443A 0.746A 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: 0.7A 341Ω 0.526A 0.861A 0.8A 300Ω 0.610A 0.976A 0.9A 268Ω 0.695A 1.089A Min Typ Max Units 190 243 293 V 243V R SET (Ω ) = = 194.4Ω 1.25A RSET = 196Ω (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 = 243Ω 0.781A 1.202A 222Ω 0.868A 1.314A 1.2A 204Ω 0.956A 1.426A 1.3A 189Ω 1.044A 1.537A 1.4A 176Ω 1.133A 1.647A 1.5A 165Ω 1.222A 1.757A Table 3. MIC20x9 RSET Table 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 190V = 0.97 A 196Ω 293V = 1.5A 196Ω Giving us a maximum ILIMIT variation over temperature of: ILIMIT_MIN ILIMIT_TYP ILIMIT_MAX 0.97A (-22%) 1.25A 1.5A (+20%) ILIMIT_MAX = February 2011 1A 1.1A 23 M9999-020311-D Micrel, Inc. MIC20xx Family NORMALIZED OUTPUT CURRENT (A) 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. 1.2 Normalized Output Current vs. Output Voltage (5V) 1.0 0.8 0.6 0.4 0.2 0 0 1 2 3 4 5 OUTPUT VOLTAGE (V) 6 NORMALIZED OUTPUT CURRENT (A) Figure 6. Normalized Output Current vs. Output Voltage Figure 4. IOUT in Current Limiting for VIN - VOUT < 1V 1.2 Normalized Output Current vs. Output Voltage (2.5V) 1.0 0.8 0.6 0.4 0.2 0 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 2004 2005X 2006 2007 2008 2009X 2013 2014 2015 2016 2017 2018 2019X Only parts in bold have CSLEW pin. (Not available in 5-pin SOT-23 packages). 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. 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. February 2011 24 M9999-020311-D Micrel, Inc. 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. Typical Turn-on Times vs. External C Capacitance SLEW 14 0.014 TON 12 0.012 TDELAY TIME (mS) 10 0.01 0.0088 6 0.006 4 0.004 TRISE 2 0.002 0 0 4 4.5 3 3.5 2 2.5 0 0.5 0 1 0 1.5 0 0 0 0 0 0 0 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 2004 2005X 2006 2007 2008 2009X 2013 2014 2015 2016 2017 2018 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 Figure 9. VUVLO Operation VUVLO and Kickstart™ operate independently in the MIC2016. If the high current surge allowed by Kickstart™ causes VIN to dip below the VUVLO trip point for more than 32ms, VUVLO will disengage the load even though the Kickstart™ timer has not timed out. IIN_LOAD Input Supply VIN + R1 R2 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. 25 M9999-020311-D Micrel, Inc. MIC20xx Family limit (ILIMIT_2nd) to the load for 128ms and then normal (primary) current limiting goes into action. During Kickstart™ 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 Kickstart™ period. Once the Kickstart™ 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 Kickstart™ 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. Kickstart™ may be over-ridden by the thermal protection circuit and if sufficient internal heating occurs, Kickstart™ will be terminated and IOUT Æ 0A. Upon cooling, if the load is still present IOUT Æ ILIMIT, not ILIMIT_2nd. The value of R2 is calculated using: R2 = VVUVLO IDIV The vale of R1 is calculated using: ⎛ VTRIP R1 = R2 × ⎜⎜ ⎝ 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 100kΩ. Using the divider loading current IDIV of 100uA, the value of R2 can be estimated by: R2 = 0.25 V = 2.5kΩ 100µA Now the value of R1 can be calculated by: ⎛ 4.75 V ⎞ − 1⎟ = 45k R1 = 2.5kΩ × ⎜ ⎝ 0.25 V ⎠ 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. Figure 11. Kickstart™ Automatic Load Discharge Kickstart™ 2003 2004 2005X 2006 2007 2008 2009X 2013 2014 2015 2016 2017 2018 2019X 2004 2005X 2006 2007 2008 2009X 2013 2014 2015 2016 2017 2018 2019X Only parts in bold have automatic load discharge. Only parts in bold have Kickstart™. (Not available in 5-pin SOT-23 packages). 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 CableCARD™. 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 Kickstart™ 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, Kickstart™ is a forced override of the normal current limiting function provided by the switch. The Kickstart™ period is governed by an internal timer which allows current to pass up to the secondary current February 2011 2003 26 M9999-020311-D Micrel, Inc. MIC20xx Family MOSFET. The total resistance of the MOSFET and internal resistances is typically 126Ω. assuming a constant case temperature of 85°C. The plots also assume a worst case RON of 140mΩ at a die temperature of 135°C. Under these conditions it is clear that an SOT-23 packaged device will be on the verge of thermal shutdown, typically 140°C die temperature, when operating at a load current of 1.25A. For this reason we recommend using MLF® packaged switches for any design intending to supply continuous currents of 1A or more. Supply Filtering A minimum 1μF 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 10μF 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 0.01μF to 0.1μF are recommended. Again, good quality, low ESR capacitors should be chosen. Die Temperature vs. Output Current (T CASE =85°C) 160 140 120 100 SOT-23 MLF 80 60 40 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: PD = R DS(ON) × (IOUT ) 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 2 To relate this to junction temperature, the following equation can be used: TJ = PD × R θ( J− A ) + TA Where: TJ = junction temperature, TA = ambient temperature Rθ(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® (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’s2011 use or sale of Micrel Products for use in life support appliances, agrees to fully February 29devices or systems is a Purchaser’s own risk and Purchaser M9999-020311-D indemnify Micrel for any damages resulting from such use or sale. © 2009 Micrel, Incorporated.