MIC2025/2075 Micrel MIC2025/2075 Single-Channel Power Distribution Switch Preliminary Information General Description Features The MIC2025 and MIC2075 are high-side MOSFET switches optimized for general-purpose power distribution requiring circuit protection. The MIC2025/75 are internally current limited and have thermal shutdown that protects the device and load. The MIC2075 offers “smart” thermal shutdown that reduces current consumption in fault modes. When a thermal shutdown fault occurs, the output is latched off until the faulty load is removed. Removing the load or toggling the enable input will reset the device output. • • • • • • • • • • • • Both devices employ soft-start circuitry that minimizes inrush current in applications where highly capacitive loads are employed. A fault status output flag is provided that is asserted during overcurrent and thermal shutdown conditions. The MIC2025/75 is available in the MM8™ 8-lead MSOP and 8-lead SOP. 140mΩ maximum on-resistance 2.7V to 5.5V operating range 500mA minimum continuous output current Short-circuit protection with thermal shutdown Fault status flag with 3ms filter eliminates false assertions Undervoltage lockout Reverse current flow blocking (no “body diode”) Circuit breaker mode (MIC2075) reduces power consumption Logic-compatible input Soft-start circuit Low quiescent current Pin-compatible with MIC2525 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 10k Logic Controller VIN 1µF MIC2025/75 ON/OFF OVERCURRENT GND EN OUT FLG IN GND OUT NC Load NC 0.1µF MM8 is a trademark of Micrel, Inc. Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com March 2000 1 MIC2025/2075 MIC2025/2075 Micrel Ordering Information Part Number Enable Temperature Range Package MIC2025-1BM Active High –40°C to +85°C 8-lead SOP MIC2025-2BM Active Low –40°C to +85°C 8-lead SOP MIC2025-1BMM Active High –40°C to +85°C 8-lead MSOP MIC2025-2BMM Active Low –40°C to +85°C 8-lead MSOP MIC2075-1BM Active High –40°C to +85°C 8-lead SOP MIC2075-2BM Active Low –40°C to +85°C 8-lead SOP MIC2075-1BMM Active High –40°C to +85°C 8-lead MSOP MIC2075-2BMM Active Low –40°C to +85°C 8-lead MSOP Pin Configuration MIC2025/75 EN 1 8 OUT FLG 2 7 IN GND 3 6 OUT NC 4 5 NC 8-Lead SOP (BM) 8-Lead MSOP (BMM) Pin Description Pin Number Pin Name 1 EN Switch Enable (Input): Active-high (-1) or active-low (-2). 2 FLG Fault Flag (Output): Active-low, open-drain output. Indicates overcurrent or thermal shutdown conditions. Overcurrent condition must exceed tD in order to assert FLG. 3 GND Ground 4 NC not internally connected 5 NC not internally connected 6, 8 OUT 7 IN MIC2025/2075 Pin Function Supply (Output): Pins must be connected together. Supply Voltage (Input). 2 March 2000 MIC2025/2075 Micrel Absolute Maximum Ratings (Note 1) Operating Ratings (Note 2) Supply Voltage (VIN) ........................................ –0.3V to 6V Fault Flag Voltage (VFLG) .............................................. +6V Fault Flag Current (IFLG) ............................................ 25mA Output Voltage (VOUT) .................................................. +6V Output Current (IOUT) ............................... Internally Limited Enable Input (IEN) ..................................... –0.3V to VIN +3V Storage Temperature (TS) ....................... –65°C to +150°C ESD Rating, Note 3 Supply Voltage (VIN) ................................... +2.7V to +5.5V Ambient Temperature (TA) ......................... –40°C to +85°C Junction Temperature (TJ) ....................... Internally Limited Thermal Resistance SOP (θJA) .......................................................... 160°C/W MSOP(θJA) ........................................................ 206°C/W Electrical Characteristics VIN = +5V; TA = 25°C, bold values indicate –40°C ≤ TA ≤ +85°C; unless noted Symbol Parameter Condition IDD Supply Current VEN Enable Input Voltage Min Typ Max Units MIC20x5-1, VEN ≤ 0.8V, (switch off), OUT = open 0.75 5 µA MIC20x5-2, VEN ≥ 2.4V, (switch off), OUT = open 0.75 5 µA MIC20x5-1, VEN ≥ 2.4V, (switch on), OUT = open 160 µA MIC20x5-2, VEN ≤ 0.8V, (switch on), OUT = open 160 µA 2.4 V low-to-high transition high-to-low transition 2.1 0.8 Enable Input Hysteresis IEN Enable Input Current VEN = 0V to 5.5V –1 Control Input Capacitance RDS(on) Switch Resistance 1.9 V 200 mV 0.01 1 1 µA pF VIN = 5V, IOUT = 500mA 90 140 mΩ VIN = 3.3V, IOUT = 500mA 100 160 mΩ 10 µA Output Leakage Current MIC2025/2075 (output off) OFF Current in Latched Thermal Shutdown MIC2075 (during thermal shutdown state) tON Output Turn-On Delay RL = 10Ω, CL = 1µF, see “Timing Diagrams” 1 2.5 6 ms tR Output Turn-On Rise Time RL = 10Ω, CL = 1µF, see “Timing Diagrams” 0.5 2.3 5.9 ms tOFF Output Turnoff Delay RL = 10Ω, CL = 1µF, see “Timing Diagrams” 50 100 µs tF Output Turnoff Fall Time RL = 10Ω, CL = 1µF, see “Timing Diagrams” 50 100 µs ILIMIT Short-Circuit Output Current VOUT = 0V, enabled into short-circuit. 0.7 1.25 A Current-Limit Threshold ramped load applied to output, Note 4 0.85 1.25 A Short-Circuit Response Time VOUT = 0V to IOUT = ILIMIT (Short applied to output) Overcurrent Flag Response Delay VIN = 5V, apply VOUT = 0V until FLG low 1.5 3 7 ms VIN = 3.3V, apply VOUT = 0V until FLG low 1.5 3 8 ms VIN rising 2.2 2.5 2.7 V VIN falling 2.0 2.3 2.5 V tD Undervoltage Lockout Threshold March 2000 3 µA 50 0.5 µs 24 MIC2025/2075 MIC2025/2075 Symbol Micrel Parameter Condition Error Flag Output Resistance Min Typ Max Units IL = 10mA, VIN = 5V 8 25 Ω IL = 10mA, VIN = 3.3V 11 40 Ω 10 µA Error Flag Off Current VFLAG = 5V Overtemperature Threshold TJ increasing 140 °C TJ decreasing 120 °C Note 1. Exceeding the absolute maximum rating may damage the device. Note 2. The device is not guaranteed to function outside its operating rating. Note 3. Devices are ESD sensitive. Handling precautions recommended. Note 4. See “Functional Characteristics: Current-Limit Response” graph. Test Circuit VOUT Device Under OUT Test IOUT RL CL Timing Diagrams tR tF 90% VOUT 90% 10% 10% Output Rise and Fall Times VEN 50% tOFF tON 90% VOUT 10% Active-Low Switch Delay Times (MIC20x5-2) VEN 50% tOFF tON VOUT 90% 10% Active-High Switch Delay Times (MIC20x5-1) MIC2025/2075 4 March 2000 MIC2025/2075 Micrel Supply On-Current vs. Temperature On-Resistance vs. Temperature 140 5V 120 100 80 3.3V 60 40 20 4 3.3V 100 5V 80 60 40 IOUT = 500mA VIN = 3.3V 3 2 VIN = 5V RL=10Ω CL=1µF 1 20 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) Supply On-Current vs. Input Voltage On-Resistance vs. Input Voltage Turn-On Rise Time vs. Input Voltage 200 RESISTANCE (mΩ) 200 CURRENT (µA) 120 150 -40°C 100 +25°C 50 +85°C 5.0 4.0 150 RISE TIME (ms) CURRENT (µA) 140 5 RISE TIME (ms) 160 160 ON-RESISTANCE (mΩ) 180 Turn-On Rise Time vs. Temperature +85°C 100 +25°C 50 -40°C +85°C 3.0 +25°C -40°C 2.0 1.0 RL=10Ω CL=1µF IOUT = 500mA VIN = 3.3V 600 VIN = 5V 400 200 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 800 Short-Circuit Current-Limit vs. Input Voltage +25°C CURRENT LIMIT (mA) 700 600 500 +85°C -40°C 400 300 200 100 0 2.5 March 2000 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V) 5.5 Current-Limit Threshold vs. Temperature 1200 1200 1100 1000 900 800 700 600 +85°C +25°C -40°C 500 400 300 200 100 0 2.5 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V) 1000 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V) 5.5 Enable Threshold vs. Temperature 2.5 VIN = 3.3V 800 600 0 2.5 5.5 ENABLE THRESHOLD (V) CURRENT LIMIT (mA) 1000 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V) VIN = 5V 400 200 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) Current-Limit Threshold vs. Input Voltage 5 2.0 VEN RISING 1.5 VEN FALLING 1.0 0.5 VIN = 5V 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 2.5 ENABLE THRESHOLD (V) Short-Circuit Current-Limit vs. Temperature 800 0 2.5 5.5 CURRENT LIMIT THRESHOLD (mA) 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V) CURRENT LIMIT THRESHOLD (mA) 0 2.5 5.5 Enable Threshold vs. Input Voltage 2.0 VEN RISING 1.5 VEN FALLING 1.0 0.5 TA = 25°C 0 2.5 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V) 5.5 MIC2025/2075 MIC2025/2075 Micrel 5 4 3 VIN = 3.3V VIN = 5V 2 1 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) MIC2025/2075 DELAY TIME (ms) DELAY TIME (ms) 5 4 3 Flag Delay vs. Input Voltage UVLO Threshold vs. Temperature 3.0 VIN RISING +85°C UVLO THRESHOLD (V) Flag Delay vs. Temperature +25°C 2 -40°C 1 0 2.5 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V) 6 5.5 2.5 2.0 VIN FALLING 1.5 1.0 0.5 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) March 2000 MIC2025/2075 Micrel Functional Characteristics UVLO—VIN Falling (MIC2025-1) VFLG VIN (2V/div.) (2V/div.) VIN VFLG (1V/div.) (1V/div.) UVLO—VIN Rising (MIC2025-1) Turn-On Response (MIC2025-1) Turnoff Response (MIC2025-1) 640mA IOUT (200mA/div.) VIN = 5V CL = 147µF RL = 35Ω 144mA VIN = 5V CL = 147µF RL = 35Ω 144mA TIME (2.5ms/div.) Inrush Current Response (MIC2025-1) Enable Into Short (MIC2025-1) VFLG VEN (5V/div.) (10V/div.) TIME (1ms/div.) VIN = 5V RL = 35Ω 3.1ms (tD) VIN = 5V VOUT IOUT (500mA/div.) (2V/div.) VEN VFLG (5V/div.) (10V/div.) VEN VOUT VFLG (5V/div.) (5V/div.) (10V/div.) TIME (25ms/div.) CL = 210µF IOUT (200mA/div.) VEN = VIN VIN = 5V CL = 57µF RL = 35Ω TIME (10ms/div.) IOUT (200mA/div.) VEN VOUT VFLG (5V/div.) (5V/div.) (10V/div.) IOUT (100mA/div.) VOUT (2V/div.) VEN = VIN VIN = 5V CL = 57µF RL = 35Ω CL = 310µF CL = 110µF CL = 10µF TIME (1ms/div.) March 2000 2.3V VOUT IOUT (100mA/div.) (2V/div.) 2.5V 640mA Short-Circuit Current TIME (1ms/div.) 7 MIC2025/2075 MIC2025/2075 Micrel VIN VFLG (5V/div.) (10V/div.) Current-Limit Response (Ramped Load Into Short—MIC2025-1) VIN = 5V CL = 47µF VOUT (5V/div.) Short Removed Short-Circuit Current (650mA) Thermal Shutdown 640mA Short-Circuit Current TIME (100ms/div.) TIME (500µs/div.) Current-Limit Transient Response (MIC2025-1) Thermal Shutdown Response (Output Reset by Removing Load—MIC2075-1) VFLG VEN (5V/div.) (10V/div.) No Load VIN = 5V CL = 47µF IOUT (5A/div.) Current-Limit Threshold (780mA) Load VFLG (5V/div.) No Load VOUT (5V/div.) IOUT (500mA/div.) Current-Limit Transient Response (Enable Into Short—MIC2025-1) Load VOUT (5V/div.) VOUT (5V/div.) IOUT (5A/div.) IOUT (500mA/div.) VIN = 5V CL = 47µF Output Latched Off Ramped Load to a Short 24µs 640mA Short-Circuit Current TIME (10µs/div.) Output is Reset (Load Removed) Thermal Shutdown VIN = 5V TIME (100ms/div.) VIN = 5V Enable Reset Output Reset IOUT (500mA/div.) VOUT (5V/div.) VEN VFLG (5V/div.) (10V/div.) Thermal Shutdown (Output Reset by Toggling Enable—MIC2075-1) Ramped Load to a Short Thermal Shutdown RL = 35Ω RL = 35Ω TIME (100ms/div.) MIC2025/2075 8 March 2000 MIC2025/2075 Micrel Block Diagram EN OSC. THERMAL SHUTDOWN UVLO 1.2V REFERENCE CHARGE PUMP GATE CONTROL IN CURRENT LIMIT FLAG RESPONSE DELAY OUT FLG GND Power Dissipation The device’s junction temperature depends on 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. PD = RDS(on) × IOUT2 Functional Description 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. If VOUT is greater than VIN, current will flow from OUT to IN since the switch is bidirectional when enabled. 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 MIC2025/75 avoids undesirable current flow from OUT to IN. 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. The MIC2025 will automatically reset its output should the die temperature cool down to 120°C. The MIC2025 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. If the MIC2075 goes into thermal shutdown, its output will latch off and 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 details. Depending on 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. The worst-case scenario of thermal shutdown is that of a short-circuit fault and is shown in the in the “Function Characteristics: Thermal Shutdown Response” graph. March 2000 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: 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 virtual and has no voltage drop. The reaction to an overcurrent condition varies with three scenarios: Switch Enabled into Short-Circuit If a switch is enabled into a heavy load or short-circuit, the switch immediately enters into a constant-current mode, reducing the output voltage. The FLG signal is asserted indicating an overcurrent condition. See the Short-Circuit Response graph under Functional Characteristics. 9 MIC2025/2075 MIC2025/2075 Micrel Short-Circuit Applied to Enabled Output When a heavy load or short-circuit is applied, 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. See the Short-Circuit Transient Response graph under Functional Characteristics. Current-Limit Response—Ramped Load The MIC2025/75 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 until the current-limit threshold is exceeded. See the Current-Limit Response graph under Functional Characteristics. 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 where an overcurrent condition occurs, 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. The FLG response delay time tD is typically 3ms. 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. Load Removed (Output Reset) VEN Short-Circuit Fault VOUT ILIMIT IDC IOUT Thermal Shutdown Reached VFLG tD Figure 1. MIC2075-2 Timing: Output Reset by Removing Load VEN Short-Circuit Fault Load/Fault Removed VOUT ILIMIT IDC IOUT Thermal Shutdown Reached VFLG tD Figure 2. MIC2025-2 Timing MIC2025/2075 10 March 2000 MIC2025/2075 Micrel Universal Serial Bus (USB) Power Distribution The MIC2025/75 is 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 buspowered (that is, powered from the bus). Figure 5 below shows a typical USB Host application that may be suited for mobile PC applications employing USB. The requirements 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 tantulum. 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. Applications Information 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 MIC2025/75 are ideal inrush current-limiters suitable for hot-plug applications. Due to the integrated charge pump, the MIC2025/75 presents a high impedance when off and slowly becomes a low impedance as it turns on. This “softstart” feature effectively isolates power supplies from highly capacitive loads by reducing inrush current during hot-plug events. Figure 3 shows how the MIC2075 may be used in a 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 will be selected to match the length of the transient. MIC2025-2 1 VCC 2 0.1 µF to "Hot" Receptacle 3 4 EN OUT FLG IN GND OUT NC NC 8 7 Backend Function 6 5 CBULK GND Adaptor Card Figure 3. Hot Plug Application V+ Logic Controller MIC2025 10k 1 OVERCURRENT R C 2 3 4 EN OUT FLG IN GND OUT NC NC 8 7 6 5 Figure 4. Transient Filter March 2000 11 MIC2025/2075 MIC2025/2075 Micrel VCC 5.0V 4.50V to 5.25V Upstream VBUS 100mA max. VBUS 10k 3.3V MIC5203-3.3 IN D+ 1µF D– 3.3V USB Controller VIN OUT 1µF GND Ferrite Beads MIC2025/75 ON/OFF EN OVERCURRENT GND GND VBUS OUT FLG IN GND OUT D+ 0.01µF 120µF USB Port GND NC NC D– 0.1µF Data Data Figure 5 USB Host Application 1.5k 3.3V USB Upstream Connector MIC5203-3.3 (LDO) VBUS IN D+ D– VIN OUT GND EN ON/OFF OVERCURRENT GND GND 0.1µF Ferrite Beads MIC2025/75 USB Logic Controller 0.1µF FLG IN GND OUT NC 1.5K VBUS OUT D+ 120µF 0.01µF D– GND NC USB Downstream Connector (Up to four ganaged ports) 0.1µF Data Data Figure 6. USB Bus-Powered Hub MIC2025/2075 12 March 2000 MIC2025/2075 Micrel Package Information 0.026 (0.65) MAX) PIN 1 0.157 (3.99) 0.150 (3.81) DIMENSIONS: INCHES (MM) 0.020 (0.51) 0.013 (0.33) 0.050 (1.27) TYP 0.064 (1.63) 0.045 (1.14) 45° 0.0098 (0.249) 0.0040 (0.102) 0.197 (5.0) 0.189 (4.8) 0°–8° 0.010 (0.25) 0.007 (0.18) 0.050 (1.27) 0.016 (0.40) SEATING PLANE 0.244 (6.20) 0.228 (5.79) 8-Lead SOP (M) 0.122 (3.10) 0.112 (2.84) 0.199 (5.05) 0.187 (4.74) DIMENSIONS: INCH (MM) 0.120 (3.05) 0.116 (2.95) 0.036 (0.90) 0.032 (0.81) 0.043 (1.09) 0.038 (0.97) 0.012 (0.30) R 0.012 (0.03) 0.0256 (0.65) TYP 0.008 (0.20) 0.004 (0.10) 5° MAX 0° MIN 0.007 (0.18) 0.005 (0.13) 0.012 (0.03) R 0.039 (0.99) 0.035 (0.89) 0.021 (0.53) MM8™ 8-Pin MSOP (MM) March 2000 13 MIC2025/2075 MIC2025/2075 MIC2025/2075 Micrel 14 March 2000 MIC2025/2075 March 2000 Micrel 15 MIC2025/2075 MIC2025/2075 Micrel MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB USA http://www.micrel.com This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. © 2000 Micrel Incorporated MIC2025/2075 16 March 2000