MIC5020 Micrel, Inc. MIC5020 Current-Sensing Low-Side MOSFET Driver General Description Features The MIC5020 low-side MOSFET driver is designed to operate 11V to 50V operation at frequencies greater than 100kHz (5kHz PWM for 2% to 175ns rise/fall time driving 2000pF 100% duty cycle) and is an ideal choice for high-speed ap- TTL compatible input with internal pull-down resistor plications such as motor control, SMPS (switch mode power Overcurrent limit supplies), and applications using IGBTs. The MIC5020 can Fault output indication also operate as a circuit breaker with or without automatic Gate to source protection retry. The MIC5020s maximum supply voltage lends itself Compatible with current sensing MOSFETs to control applications using up to 50V. The MIC5020 can Applications control MOSFETs that switch voltages greater than 50V. Lamp control A rising or falling edge on the input results in a current source Heater control or sink pulse on the gate output. This output current pulse Motor control can turn on or off a 2000pF MOSFET in approximately 175ns. Solenoid switching The MIC5020 then supplies a limited current (< 2mA), if Switch-mode power supplies necessary, to maintain the output state. Circuit breaker An overcurrent comparator with a trip voltage of 50mV makes the MIC5020 ideal for use with a current sensing MOSFET. An external low value resistor may be used instead of a sensing MOSFET for more precise overcurrent control. An optional external capacitor connected to the C pin may be T Ordering Information used to control the current shutdown duty cycle from 20% Part Number Temperature to < 1%. A duty cycle from 20% to about 75% is possible Range Package with an optional pull-up resistor from C to V . An open Standard Pb-Free T DD collector output provides a fault indication when the sense MIC5020BM MIC5020YM 40C to +85C 8-pin SOIC inputs are tripped. The MIC5020 is available in 8-pin SOIC package. Other members of the MIC502x series include the MIC5021 high-side driver and the MIC5022 half-bridge driver with a cross-conduction interlock. Typical Application V+ +11V to +50V MIC5020 1 8 10F N-Channel V Gate DD Power MOSFET 2 7 150kHz max. Input Sense- 3 6 Fault 50mV Sense+ R = S E N S E I 4 5 TRIP C Gnd optional* T R S E N S E * increases time before retry Low-Side Driver with Overcurrent Trip and Retry Micrel, Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel + 1 (408) 944-0800 fax + 1 (408) 474-1000 MIC5020 Micrel, Inc. Pin Conguration 1 V Gate 8 DD 2 Input Sense- 7 Fault Sense+ 3 6 4 C Gnd 5 T SOIC Package (M) Block Diagram 6V Internal Regulator I 1 Fault C T C Normal INT 2I 1 Fault Q1 Sense+ V DD Sense- 50mV ON OFF 6V ONE- 10I I Gate 2 2 Input SHOT Transistor Count: 82 Pin Description Pin Number Pin Name Pin Function 1 V Supply: +11V to +50V. Decouple with 10F capacitor. DD 2 Input TTL Compatible Input: Logic high turns the external MOSFET on. An internal pull-down returns an open pin to logic low. 3 Fault Overcurrent Fault Indicator: When the sense voltage exceeds threshold, open collector output is open circuit for 5s (t ), then pulled low for G(ON) t . t is adjustable from C . G(OFF) G(OFF) T 4 C Retry Timing Capacitor: Controls the off time (t ) of the overcurrent T G(OFF) retry cycle. (Duty cycle adjustment.) Open = 20% duty cycle. Capacitor to Ground = approx. 20% to <1% duty cycle. Pull-Up resistor = approx. 20% to approx. 75% duty cycle. Ground = maintained shutdown upon overcurrent condition. 5 Gnd Circuit Ground 6 Sense + Current Sense Comparator (+) Input: Connect to high side of sense resistor or current sensing MOSFET sense lead. A built-in offset in conjunction with R sets the load overcurrent trip point. SENSE 7 Sense Current Sense Comparator () Input: Connect to the low side of the sense resistor (usually power ground). 8 Gate Gate Drive: Drives the gate of an external power MOSFET. Also limits V GS to 15V max. to prevent Gate to Source damage. Will sink and source current. MIC5020 2 July 2005