MIC2073/2074 Dual-Channel Power Distribution Switch General Description Features The MIC2073/2074 are high-side MOSFET switches optimized for general-purpose power distribution requiring circuit protection. The MIC2073/2074 are internally current limited and have thermal shutdown for protecting the device and load. The MIC2074 offers “smart” shutdown that reduces current consumption in fault mode. When a fault occurs due to thermal shutdown, the output is latched off. The MIC2074s’ output will be reset, enabling the output, either by removing the load or toggling the ENABLE pin. Both devices employ soft-start circuitry that minimizes inrush current in applications where highly capacitive loads are employed. A fault status output flag is asserted during overcurrent or thermal shutdown conditions. Transient faults are internally filtered. The MIC2073/2074 are available in an 8-pin SOIC. All support documentation can be found on Micrel’s web site at: www.micrel.com. • • • • • • • • • • • • • • • 115 mΩ typical R DS(ON) at 5.0 V 210 mΩ maximum R DS(ON) at 5.0 V 2.7 V to 5.5 V operating range 500 mA minimum continuous current per channel Short circuit protection with thermal shutdown Thermally isolated channels Fault status flag (FLGA/B) separate for each channel 3ms fault flag delay (TD) eliminates false assertions UVLO (Undervoltage Lockout) Reverse current flow blocking (no “body diode”) Circuit breaker mode (MIC2074) Logic-compatible inputs Soft-start circuit Low quiescent current Pin compatible with the MIC2026/2076 B B Applications • USB peripherals • General purpose power switching • ACPI power distribution • Notebook PCs • PDAs • PC card hot swap _________________________________________________________________________________________________ Typical Application VCC 2.7V to 5.5V VCONT. 10k 10k Logic Controller VIN ON/OFF OVERCURRENT OVERCURRENT ON/OFF MIC2073/74 ENA FLGA FLGB OUTA IN GND ENB OUTB Load 0.1µF Load Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com January 2009 M9999-011209 Micrel, Inc. MIC2073/2074 Ordering Information Part Number Enable MIC2073-1YM Active High MIC2073-2YM Active Low MIC2074-1YM Active High MIC2074-2YM Active Low NOTE: Package 8- Pin SOIC 1. MIC2073/2074 are Temperature rated from –40°C to +85°C 2. MIC2073/2074 are all lead free Pin Configuration ENA 1 8 OUTA FLGA 2 7 IN FLGB 3 6 GND ENB 4 5 OUTB 8-Pin SOIC (M) MIC2073/2074 Pin Description Pin Number Pin Name 1 ENA Switch A Enable (Input): Logic-compatible, enable input. Active high (-1) or active low (-2). FLGA Fault Flag A (Output): Active-low, open-drain output. Low indicates overcurrent or thermal shutdown conditions. Overcurrent conditions must last longer than t D in order to assert FLGA. FLGA pin can be left floating; however, fault status information will not be available. 3 FLGB Fault Flag B (Output): Active-low, open-drain output. Low indicates overcurrent or thermal shutdown conditions. Overcurrent conditions must last longer than t D in order to assert FLGB. FLGB pin can be left floating; however, fault status information will not be available. 4 ENB Switch B Enable (Input): Logic-compatible enable input. Active-high (-1) or active-low (-2). 5 OUTB Switch B (Output) 6 GND Ground 7 IN 8 OUTA 2 January 2009 Pin Function B B B B Input: Switch and logic supply input. Switch A (Output) 2 M9999-011209 Micrel, Inc. MIC2073/2074 Absolute Maximum Ratings (1) Operating Ratings (2) Supply Voltage (V IN ) .................................... –0.3 V to +6 V Fault Flag Voltage (V FLG ) ..............................................+6 V Fault Flag Current (I FLG ).............................................25 mA Output Voltage (V OUT ) ...................................................+6 V Output Current (I OUT ).................................Internally Limited Enable Input (V EN )...................................... –0.3 V to 6.0 V Storage Temperature (T S ) .....................–65°C to +150 °C ESD Rating(3) HBM ........................................................................ 1 kV MM ........................................................................200 V Supply Voltage (V IN ) ................................. +2.7 V to +5.5 V Ambient Temperature (T A )......................... –40°C to +85°C Junction Temperature Range (T J ) ............ Internally Limited Thermal Resistance SOIC (θ JA ) .......................................................160°C/W P B B B B B B B P B B B B B B B B B B B B B B B Electrical Characteristics(4) P VIN = 5 V; TA = 25°C, bold values indicate –40°C ≤ TA ≤ +85°C; unless noted Symbol Parameter Condition Min Typ Max Units MIC2073-1, V ENA = V ENB ≤ 0.8 V (switch off), OUT = open 0.40 5 µA MIC2073-2, V ENA = V ENB ≥ 2.4 V (switch off), OUT = open 7.5 20 µA MIC2073-1, V ENA = V ENB ≥ 2.4 V (switch on), OUT = open 100 160 µA MIC2073-2, V ENA = V ENB ≤ 0.8 V (switch on), OUT = open 100 160 µA low-to-high transition 1.6 2.4 V B B B I DD B Supply Current B B B V EN B B B B B B B B B B B B Enable Input Threshold B high-to-low transition V EN_HYST B B Enable Input Hysteresis I EN Enable Input Current CEN Enable Input Capacitance B B R DS(ON) B I LIMIT B B 0.8 V EN = 0 V to 5.5 V B -1 B 1.40 V 225 mV 0.01 1 1 µA pF MIC2073/2074 , V IN = 5.0 V, I OUT = 500 mA 115 170 mΩ MIC2073/2074 V IN = 3.3 V, I OUT = 500 mA 145 210 mΩ 10 µA B B B B Switch Resistance B B B B Output Leakage Current MIC2073-1/2074-1, VENx ≤ 0.8 V; MIC2073-2/2074-2, VENx ≥ 2.4 V, (output off) Off Current (Thermal Shutdown) MIC2074, Thermal shutdown state Short-Circuit Output Current V OUT = 0V, enabled into short-circuit Current-Limit Threshold Ramped load applied to output Undervoltage Lockout Threshold V IN rising V IN falling 50 0.7 1.25 A 1.0 1.25 A 2.2 2.45 2.7 V 2.0 2.25 2.5 V I L = 10 mA, V IN = 5.0 V 12 25 I L = 10 mA, V IN = 3.3 V 14 40 B B 0.5 µA B VUVLO B B Error Flag Output Resistance B B Error Flag Off Current January 2009 B B B B B B B B V FLAG = V IN B B B 10 B 3 Ω µA M9999-011209 Micrel, Inc. MIC2073/2074 VIN = 5 V; TA = 25°C, bold values indicate –40°C ≤ TA ≤ +85°C; unless noted (Continued) Symbol Parameter Condition tSC_RESP Short-Circuit Response Time V OUT = 0 V, to IOUT = ILIMIT (short applied to output) 20 t ON Output Turn-On Delay R L = 10 Ω, C L = 1 µF, see “Timing Diagrams” 1.3 5 ms tR Output Turn-On Rise Time R L = 10 Ω, C L = 1 µF, see “Timing Diagrams” 1.15 4.9 ms t OFF Output Turn-Off Delay R L = 10 Ω, C L = 1 µF, see “Timing Diagrams” 35 100 µs tF Output Turn-Off Fall Time R L = 10 Ω, C L = 1 µF, see “Timing Diagrams” 32 100 µs tD Overcurrent Flag Response Delay 4 7 ms B B B B B B B B TOVERTEMP Overtemperature Threshold B Min B B B B B B B B B B B B B B B B B VIN = 5 V apply VOUT 0 V until FLG LOW VIN = 3.3 V apply VOUT 0 V until FLG LOW (5) 0.5 1.5 Typ Max Units µs 3 ms T J increasing, each switch T J decreasing, each switch 140 120 °C °C T J increasing, both switches T J decreasing, both switches 160 150 °C °C B B B B B B B B Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. Devices are ESD sensitive. Handling precautions recommended. 4. Specification for packaged product only. 5. If there is a fault on one channel, that channel will shut down when the die reaches approximately 140°C. If the die reaches approximately 160°C, both channels will shut down, even if neither channel is in current limit. January 2009 4 M9999-011209 Micrel, Inc. MIC2073/2074 Test Circuit VOUT Device Under OUT Test RL CL Timing Diagrams tR tF 90% 90% VOUT 10% 10% Output Rise and Fall Times VEN 50% tOFF tON VOUT 90% 10% Active-Low Switch Delay Times (MIC2073-2/2074-2) Active-High Switch Delay Time (MIC2073-1/2074-1) January 2009 5 M9999-011209 Micrel, Inc. MIC2073/2074 Typical Characteristics 180 180 5V 120 100 80 3.3V 60 40 120 5V 100 80 60 40 3 2 VIN = 3.3V 1 VIN = 5V Supply On-Current vs. Input Voltage On-Resistance vs. Input Voltage Turn-On Rise Time vs. Input Voltage 100 50 +85°C 1000 +25°C 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V) Short-Circuit Current-Limit vs. Temperature VIN = 3.3V 800 VIN = 5V 600 400 200 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 1000 900 Short-Circuit Current-Limit vs. Input Voltage 800 700 +85°C +25°C -40°C 600 500 400 300 200 100 0 2.5 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V) January 2009 5.5 +25°C 100 -40°C 50 0 2.5 5.5 RISE TIME (ms) -40°C 2.0 +85°C 150 1200 1000 800 1.5 +85°C +25°C -40°C 1.0 0.5 IOUT = 500mA 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V) 0 2.5 5.5 Current-Limit Threshold vs. Temperature 100 90 VIN = 5V VIN = 3.3V 600 400 200 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V) 5.5 Fall Time vs. Temperature 80 70 60 50 40 30 20 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 10 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) Current-Limit Threshold vs. Input Voltage Fall Time vs. Input Voltage 1200 100 90 +85°C 1000 800 +25°C RISE TIME (µs) 150 2.5 FALL TIME (µs) RESISTANCE (mOhm) 200 CURRENT LIMIT THRESHOLD (mA) CURRENT (µA) 4 140 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 0 2.5 CURRENT LIMIT (mA) 5 3.3V 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 200 CURRENT LIMIT (mA) 160 Turn-On Rise Time vs. Temperature 20 I = 500mA OUT 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 20 CURRENT LIMIT THRESHOLD (mA) CURRENT (µA) 140 ON-RESISTANCE (mOhms) 160 On-Resistance vs. Temperature RISE TIME (ms) Supply On-Current vs. Temperature -40°C 600 400 200 0 2.5 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V) 6 5.5 80 70 60 50 40 30 20 10 0 2.5 25°C 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V) 5.5 M9999-011209 Micrel, Inc. MIC2073/2074 Typical Characteristics (continue) VEN RISING 1.5 VEN FALLING 1.0 0.5 4 MIC2073-1 Supply Off Current vs. Temperature VIN = 3.3V VIN = 5V 3 2 1 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) Enable Threshold vs. Input Voltage Flag Delay vs. Input Voltage 5 MIC2073-1 Supply Off Current vs. Input Voltage 0.60 DELAY TIME (ms) VEN RISING 1.5 VEN FALLING 1.0 0.5 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V) UVLO THRESHOLD (V) 3.0 2.5 2.0 5.5 UVLO Threshold vs. Temperature 3.3V 5V 1.5 1.0 0.5 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) January 2009 4 3 +25°C -40°C 2 1 0 2.5 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V) 5.5 0.55 0.50 8.0 7.0 3.3V 5V 6.0 5.0 4 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 7 +25°C 0.40 0.35 0.30 -40°C 0.25 0.20 2.5 3.0 3.5 4.0 4.5 VOLTAGE (V) 5.0 5.5 MIC2073-2 Supply Off-Current vs. Input Voltage 10.0 9.0 +85°C 0.45 MIC2073-2 Supply Off-Current vs. Temperature SUPPLY OFF-CURRENT (µA) 0 2.5 SUPPLY CURRENT (µA) +85°C 2.0 0.80 0.75 0.70 0.65 0.60 0.55 0.50 5V 0.45 0.40 0.35 0.30 3.3V 0.25 0.20 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 10 SUPPLY OFF-CURRENT (µA) 2.0 2.5 ENABLE THRESHOLD (V) 5 DELAY TIME (ms) ENABLE THRESHOLD (V) 2.5 Flag Delay vs. Temperature SUPPLY CURRENT (µA) Enable Threshold vs. Temperature 9 8 85°C 7 6 -40°C 25°C 5 4 2.5 3 3.5 4 4.5 5 INPUT VOLTAGE (V) 5.5 M9999-011209 Micrel, Inc. MIC2073/2074 Functional Characteristics January 2009 8 M9999-011209 Micrel, Inc. MIC2073/2074 Functional Characteristics (continued) January 2009 9 M9999-011209 Micrel, Inc. MIC2073/2074 Functional Characteristics (continue) January 2009 10 M9999-011209 Micrel, Inc. MIC2073/2074 Block Diagram MIC2073/2074 Block Diagram Functional Description Thermal Shutdown Thermal shutdown is employed to protect the device from damage should the die temperature exceed safe margins due mainly to short circuit faults. Each channel employs its own thermal sensor. Thermal shutdown shuts off the output MOSFET and asserts the FLG output if the die temperature reaches 140°C and the overheated channel is in current limit. The other channel is not affected. If however, the die temperature exceeds 160°C, then both channels will be shut off. Upon determining a thermal shutdown condition, the MIC2074 will latch the output off. In this case, a pull-up current source is activated. This allows the output latch to automatically reset when the load (such as a USB device) is removed. The output can also be reset by toggling EN. Refer to Figure 1 for timing details. The MIC2073 will automatically reset its output when the die temperature cools down to 120°C. The MIC2073 output and FLG signal will continue to cycle on and off until the device is disabled or the fault is removed. Figure 2 depicts typical timing. Depending upon PCB layout package, ambient temperature, etc., it may take several hundred milliseconds from the incidence of the fault to the output MOSFET being shut off. This time will be shortest in the case of a dead short on the output. Input and Output IN is the power supply connection to the logic circuitry and the drain of the output MOSFET. OUT is the source of the output MOSFET. In a typical circuit, current flows from IN to OUT toward the load when the switch is enabled. An important consideration in a choosing switch is whether it has “reverse voltage protection” that is, does not have a body diode. Reverse voltage protection is important when the switch is disabled and a voltage is presented to the OUT pin that is greater than the VIN voltage. The reverse voltage protection prevents current flow in the reverse path from OUT to IN. On other hand when the switch is enabled the switch is bidirectional. In this case when a voltage is presented to the OUT pin that is greater than the VIN voltage, current will flow from OUT to IN. The output MOSFET and driver circuitry are also designed to allow the MOSFET source to be externally forced to a higher voltage than the drain (VOUT > VIN) when the switch is disabled. In this situation, the MIC2073/2074 prevents undesirable current flow from OUT to IN. January 2009 11 M9999-011209 Micrel, Inc. MIC2073/2074 • Power Dissipation The device’s junction temperature depends upon several factors such as the load, PCB layout, ambient temperature, and package type. Equations that can be used to calculate power dissipation of each channel and junction temperature are found below: • Current-Limit Response - Ramped Load The MIC2073/2074 current-limit profile exhibits a small foldback effect of about 200mA. Once this current-limit threshold is exceeded the device switches into a constant current mode. It is important to note that the device will supply current up to the current-limit threshold. PD = RDS(on) × IOUT2 Total power dissipation of the device will be the summation of PD for both channels. To relate this to junction temperature, the following equation can be used: TJ = PD × θJA + TA where: Fault Flag The FLG signal is an N-channel open-drain MOSFET output. FLG is asserted (active-low) when either an overcurrent or thermal shutdown condition occurs. In the case of an overcurrent condition, FLG will be asserted only after the flag response delay time, tD, has elapsed. This ensures that FLG is asserted only upon valid overcurrent conditions and that erroneous error reporting is eliminated. For example, false overcurrent conditions can occur during hot plug events when a highly capacitive load is connected and causes a high transient inrush current that exceeds the current-limit threshold for up to 1ms. The FLG response delay time tD is typically 3ms. TJ = junction temperature TA = ambient temperature θJA = is the thermal resistance of the package Current Sensing and Limiting The current-limit threshold is preset internally. The preset level prevents damage to the device and external load but still allows a minimum current of 500mA to be delivered to the load. The current-limit circuit senses a portion of the output MOSFET switch current. The current-sense resistor shown in the block diagram is a virtual resistor and has no voltage drop. The reaction to an overcurrent condition varies with three scenarios: • Undervoltage Lockout Undervoltage lockout (UVLO) prevents the output MOSFET from turning on until VIN exceeds approximately 2.5V. Undervoltage detection functions only when the switch is enabled. Switch Enabled into Short-Circuit If a switch is enabled into a heavy load or shortcircuit, the switch immediately enters into a constantcurrent mode, reducing the output voltage. The FLG signal is asserted indicating an overcurrent condition. Short-Circuit Fault VEN Short-Circuit Applied to Enabled Output When a heavy load or short-circuit is applied to an enabled switch, a large transient current may flow until the current-limit circuitry responds. Once this occurs, the device limits current to less than the short-circuit current limit specification. Load and Fault Removed (Output Reset) VOUT ILIMIT ILOAD IOUT VFLG Thermal Shutdown Reached 3ms typ. delay Figure 1. MIC2074-2 Fault Timing: Output Reset by Removing Load January 2009 12 M9999-011209 Micrel, Inc. MIC2073/2074 Short-Circuit Fault VEN Load and Fault Removed (Output Reset) VOUT ILIMIT ILOAD IOUT VFLG Thermal Shutdown Reached 3ms typ. delay Figure 2. MIC2073-2 Fault Timing Application Information Universal Serial Bus (USB) Power Distribution The MIC2073/2074 are ideally suited for USB (Universal Serial Bus) power distribution applications. The USB specification defines power distribution for USB host systems such as PCs and USB hubs. Hubs can either be self-powered or bus-powered (that is, powered from the bus). Figure 5 shows a typical USB Host application that may be suited for mobile PC applications employing USB. The requirement for USB host systems is that the port must supply a minimum of 500mA at an output voltage of 5V ±5%. In addition, the output power delivered must be limited to below 25VA. Upon an overcurrent condition, the host must also be notified. To support hot-plug events, the hub must have a minimum of 120µF of bulk capacitance, preferably low ESR electrolytic or tantalum. Please refer to Application Note 17 for more details on designing compliant USB hub and host systems. For bus-powered hubs, USB requires that each downstream port be switched on or off under control by the host. Up to four downstream ports each capable of supplying 100mA at 4.4V minimum are allowed. In addition, to reduce voltage droop on the upstream VBUS, soft-start is necessary. Although the hub can consume up to 500mA from the upstream bus, the hub must consume only 100mA max at start-up, until it enumerates with the host prior to requesting more power. The same requirements apply for bus-powered peripherals that have no downstream ports. Figure 6 shows a bus-powered hub. Supply Filtering A 0.1µF to 1µF bypass capacitor positioned close to VIN and GND of the device is strongly recommended to control supply transients. Without a bypass capacitor, an output short may cause sufficient ringing on the input (from supply lead inductance) to damage internal control circuitry. Printed Circuit Board Hot-Plug The MIC2073/2074 are ideal inrush current-limiters for hot plug applications. Due to their integrated charge pumps, the MIC2073/2074 present a high impedance when off and slowly becomes a low impedance as their integrated charge pumps turn on. This “soft-start” feature effectively isolates power supplies from highly capacitive loads by reducing inrush current. Figure 3 shows how the MIC2074 may be used in a card hot-plug application. In cases of extremely large capacitive loads (>400µF), the length of the transient due to inrush current may exceed the delay provided by the integrated filter. Since this inrush current exceeds the current-limit delay specification, FLG will be asserted during this time. To prevent the logic controller from responding to FLG being asserted, an external RC filter, as shown in Figure 4, can be used to filter out transient FLG assertion. The value of the RC time constant should be selected to match the length of the transient, less tD(min) of the MIC2073/2074. January 2009 13 M9999-011209 Micrel, Inc. MIC2073/2074 USB Controller MIC2073/2074 VBUS 4.7 µF to "Hot" Receptacle 1 ENA OUTA 8 2 FLGA IN 7 3 FLGB GND 6 4 ENB OUTB 5 USB Function CBULK USB Function CBULK GND Cable USB Peripheral Figure 3. Hot-Plug Application Figure 4. Transient Filter January 2009 14 M9999-011209 Micrel, Inc. MIC2073/2074 1 8 2 7 3 6 4 5 Figure 5. USB Two-Port Host Application 1 8 2 7 3 6 4 5 Figure 6. USB Two-Port Bus-Powered Hub January 2009 15 M9999-011209 Micrel, Inc. MIC2073/2074 Package Information 8-Pin SOIC (M) _________________________________________________________________________________________________ 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 The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel 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 sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2009 Micrel, Incorporated January 2009 16 M9999-011209