MIC2524/2527 Micrel MIC2524/2527 Quad USB Power Control Switch Not Recommended for New Designs Refer to MIC2027 General Description Features The MIC2524 and MIC2527 are cost-effective high-side power switches with four independently controlled channels, optimized for self-powered and bus-powered Universal Serial Bus (USB) applications. Few external components are necessary to satisfy USB requirements. The MIC2524/7 satisfies the following USB requirements: each switch channel supplies up to 500mA as required by USB downstream devices; the switch’s low on-resistance meets USB voltage drop requirements; fault current is limited to typically 750mA, well below the UL 25VA safety requirements; and a flag output is available to indicate fault conditions to the local USB controller. Soft start eliminates the momentary voltage drop on the upstream port that may occur when the switch is enabled in bus-powered applications. • • • • • • • • • • • • • • • • Additional features include thermal shutdown to prevent catastrophic switch failure from high-current loads, undervoltage lockout (UVLO) to ensure that the device remains off unless there is a valid input voltage present, and 3.3V and 5V logic compatible enable inputs. The MIC2524/7 is available in active-high and active-low versions in 16-pin DIP and SOIC packages. Compliant to USB specifications UL Recognized Component 4 independent switches 3V to 5.5V input 500mA minimum continuous load current per port 140mΩ maximum on-resistance (MIC2524) 1.25A maximum short circuit current limit Individual open-drain fault flag pins 220µA on-state supply current 1µA typical off-state supply current Output can be forced higher than input (off-state) Thermal shutdown 2.4V typical undervoltage lockout (UVLO) 1ms turn-on (soft-start) and fast turnoff Active-high or active-low enable versions 16-pin SOIC and DIP packages Applications • • • • USB bus-powered hubs USB self-powered hubs USB monitors USB printers Typical Application MIC2527 5.1V ± 3% 5V ± 1% or MIC2524 5V ±3% Ferrite Bead VBUS 10k 27k MIC5207-3.3 LDO Regulator IN 4.7 µF 3.3V USB Controller V+ OUT 1µF ON/OFF ENA OVERCURRENT GND GND 0.01µF IN IN OUTA FLGB OUTB OUTC FLGC OUTD END GND GND FLGD D+ 33µF* FLGA ENB ENC D+ D– MIC2524 MIC2527 D– GND 0.1 µF Downstream USB Port 1 500mA max. VBUS D+ 33µF* 0.01µF D– GND Downstream USB Port 2 500mA max. VBUS Bold lines indicate 0.1" wide, 1-oz. copper high-current traces. D+ 33µF* 0.01µF D– GND * 33µF, 16V tantalum or 100µF, 10V electrolytic per port Downstream USB Port 3 500mA max. VBUS D+ 33µF* 0.01µF D– GND Downstream USB Port 4 500mA max. 4-Port Self-Powered Hub UL Recognized Component Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com June 1999 1 MIC2524/2527 MIC2524/2527 Micrel Ordering Information Part Number On-Resistance Enable Temperature Range Package MIC2524-1BWM 100mΩ typ. Active High –40°C to +85°C 16-Pin SOIC MIC2524-1BN 100mΩ typ. Active High –40°C to +85°C 16-pin DIP MIC2524-2BWM 100mΩ typ. Active Low –40°C to +85°C 16-Pin SOIC MIC2524-2BN 100mΩ typ. Active Low –40°C to +85°C 16-pin DIP MIC2527-1BWM 200mΩ typ. Active High –40°C to +85°C 16-Pin SOIC MIC2527-1BN 200mΩ typ. Active High –40°C to +85°C 16-pin DIP MIC2527-2BWM 200mΩ typ. Active Low –40°C to +85°C 16-Pin SOIC MIC2527-2BN 200mΩ typ. Active Low –40°C to +85°C 16-pin DIP Pin Configuration FLGA 1 16 FLGB ENA 2 15 ENB OUTA 3 14 OUTB GND 4 13 IN(A/B) IN(C/D) 5 12 GND OUTC 6 11 OUTD ENC 7 FLGC 8 3 OUTA LOGIC, CHARGE PUMP ENB 15 FLGB 16 LOGIC, CHARGE PUMP 13 IN(A/B) 14 OUTB 6 OUTC ENC 7 FLGC 8 LOGIC, CHARGE PUMP END 10 FLGD 9 LOGIC, CHARGE PUMP 5 IN(C/D) 10 END 9 ENA 2 FLGA 1 11 OUTD FLGD 4 GND 12 16-Pin SOIC (WM) 16-Pin DIP (N) Functional Pinout Pin Description Pin Number Pin Name 1 FLGA Flag A: (Output): Channel A open-drain fault flag output. 2 ENA Enable A (Input): Channel A control input. 3 OUTA Output A: Channel A switch output. 4, 12 GND Ground: Supply return. Connect both pins to ground. 5 IN(C/D) Supply Input: Channel C and D switch, logic, and charge-pump supply input. 6 OUTC Output C: Channel C switch output. 7 ENC Enable C (Input): Channel C control input. 8 FLGC Flag C (Output): Channel C open-drain fault flag output. 9 FLGD Flag D (Output): Channel D open-drain fault flag output. 10 END Enable D (Input): Channel D control input. 11 OUTD Output D: Channel D switch output. 13 IN(A/B) Supply Input: Channel A and B switch, logic, and charge-pump supply input. 14 OUTB Output B: Channel B switch output. 15 ENB Enable B (Input): Channel B control input. 16 FLGB Flag B (Output): Channel B open-drain fault flag output. MIC2524/2527 Pin Function 2 June 1999 MIC2524/2527 Micrel Absolute Maximum Ratings (Note 1) Operating Ratings (Note 2) Supply Voltage (VIN) ..................................................... +6V Fault Flag Voltage (VFLG) .............................................. +6V Fault Flag Current (IFLG) ............................................ 50mA Output Voltage (VOUT) .................................................. +6V Output Current (IOUT) ............................... Internally Limited Control Input (VEN) ......................................... –0.3V to 12V Storage Temperature (TS) ....................... –65°C to +150°C Lead Temperature (Soldering 5 sec.) ....................... 260°C ESD Rating, Note 3 ...................................................... 2kV Supply Voltage (VIN) ...................................... +3V to +5.5V Ambient Operating Temperature (TA) ........ –40°C to +85°C Thermal Resistance SOIC (θJA) ......................................................... 120°C/W DIP(θJA) ............................................................. 130°C/W Electrical Characteristics VIN = +5V; TA = 25°C; unless noted. Parameter Condition Supply Current Enable Input Threshold Enable Input Current Min Typ Max Units Note 4, switch off, OUT = open 1.5 10 µA Note 4, all switches on, OUT = open 220 320 µA low-to-high transition 2.1 2.4 V high-to-low transition, Note 4 0.8 1.9 VEN = 0V to 5.5V –1 ±0.01 Enable Input Capacitance Switch Resistance V 1 1 µA pF MIC2524, IOUT = 500mA, each switch 100 140 mΩ MIC2527, IOUT = 500mA, each switch 200 300 mΩ Output Turn-On Delay RL = 10Ω each output 0.5 ms Output Turn-On Rise Time RL = 10Ω each output 1 ms Output Turnoff Delay RL = 10Ω each output 1 20 µs Output Turnoff Fall Time RL = 10Ω each output 1 20 µs Output Leakage Current each output (output disabled) 10 µA Continuous Load Current each output 0.5 Short-Circuit Current Limit each output (enable into load), VOUT = 4.0V 0.5 Current-Limit Threshold Overtemperature Shutdown Threshold Error Flag Output Resistance A 0.75 1.25 A ramped load applied to enabled output, VOUT ≤ 4.0V, Note 5 1.6 2.2 A TJ increasing 135 °C TJ decreasing 125 °C VIN = 5V, IL = 10mA 10 Ω VIN = 3.3V, IL = 10mA 15 Ω 1 µA Error Flag Off Current VFLAG = 5V 0.01 UVLO Threshold VIN = increasing 2.5 V VIN = decreasing 2.3 V 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. Human body model, 1.5k in series with 100pF. Note 4. Off is ≤ 0.8V and on is ≥ 2.4V for the MIC252x-1. Off is ≥ 2.4V and on is ≤ 0.8V for the MIC252x-2. The enable input has approximately 200mV of hysteresis. See control threshold charts. Note 5. See “Functional Characteristics: Current-Limit Response” photo. June 1999 3 MIC2524/2527 MIC2524/2527 Micrel Typical Characteristics VIN = 5V; TA = 25°C; one switch section; unless noted. ON-RESISTANCE (mΩ) 100 Awaiting Full Characterization Data 90 RL = 44Ω 120 100 RL = 44Ω 80 VIN = 5V T = 25°C 80 3.0 3.5 4.0 4.5 5 SUPPLY VOLTAGE (V) 60 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 5.5 On-State Supply Current vs. Supply Voltage 2.5 200 100 1.5 1.0 0.5 ALL SWITCHES OFF ALL SWITCHES ON 0 8 On-State Supply Current vs. Temperature 2.0 350 300 250 200 150 100 ALL SWITCHES ON SUPPLY CURRENT (µA) SUPPLY CURRENT (µA) 400 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 5 Awaiting Full Characterization Data 2 1 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) VCTL RISING 1.5 VCTL FALLING 2 3 4 SUPPLY VOLTAGE (V) Off-State Supply Current vs. Temperature 5 Control Threshold vs. Temperature 2.5 1.0 0.5 ALL SWITCHES OFF 0.6 2.0 1.0 8 VEN RISING 2.0 VEN FALLING 1.5 VIN = 5V 1.0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) Output Fall Time vs. Temperature 2.0 0.8 TIME (ms) TIME (µs) 3 4 5 6 7 SUPPLY VOLTAGE (V) 1.5 1.0 4 MIC2524/2527 2 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) Output Rise Time vs. Temperature 3 THRESHOLD VOLTAGE (V) 300 50 2.0 Control Threshold vs. Supply Voltage ENABLE VOLTAGE (V) SUPPLY CURRENT (µA) SUPPLY CURRENT (µA) 400 2 4 6 SUPPLY VOLTAGE (V) FALLING 1.5 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 2.0 0 RISING 2.5 Off-State Supply Current vs. Supply Voltage 500 0 UVLO Threshold Voltage vs. Temperature 3.0 Current-Limit Threshold vs. Temperature 1.8 Awaiting Full Characterization Data 0.4 0.2 CURRENT (A) OUTPUT RESISTANCE (mΩ) Output On-Resistance vs. Temperature 140 THRESHOLD VOLTAGE (V) Output On-Resistance vs. Supply Voltage 110 CURRENT LIMIT THRESHOLD 1.6 1.4 SHORT CIRCUIT CURRENT LIMIT 1.2 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) 4 1.0 -25 0 25 50 75 TEMPERATURE (°C) 100 June 1999 MIC2524/2527 Micrel Functional Characteristics Turn-On, Turnoff Characteristics VEN VOUT VFLG (2V/div.) (5V/div.) (5V/div.) 2.6V (UVLO) Threshold VFLG VOUT IOUT (200mA/div.)(5V/div.) (2V/div.) VIN = 5.0V RL = 35Ω CL = 15µF 144mA VIN = 5.0V RL = 35Ω CL = 10µF IOUT (100mA/div.) VEN (2V/div.) Input Voltage Response TIME (2.5ms/div.) Turn-On, Turnoff Characteristics Short Circuit Response (Short Applied to Output) VOUT (2V/div.) VOUT (2V/div.) VFLG (5V/div.) VEN VFLG (5V/div.) (5V/div.) TIME (100ns/div.) 1A Short Circuit Current Limit IOUT (1A/div.) IOUT (100mA/div.) 144mA RL = 35Ω CL = 150µF Thermal Shutdown TIME (500ms/div.) TIME (2.5ms/div.) VOUT IOUT (1A/div.) (2V/div.) VFLG (5V/div.) VEN (5V/div.) Short Circuit Response Enable into Short Circuit Thermal Shutdown 1.1A Short Circuit Current-Limiting TIME (250ms/div.) June 1999 5 MIC2524/2527 MIC2524/2527 Micrel Current-Limit Response (Ramped Load) VOUT (2V/div.) VFLG (5V/div.) VFLG (5V/div.) VOUT (5V/div.) Short Circuit Transient Response (Short Applied to Output) Current Limit Threshold 1A Current Limit 1A Current Limit IOUT (1A/div.) IOUT (1A/div.) 2.76A TIME (500µs/div.) TIME (1ms/div.) Test Circuit 5V 10k (1 output shown) 0.1µF MIC2524/7 ENA FLGA ENB IN Ferrite Bead FLGB NC IOUT OUTA CL OUTB ENC OUTC FLGC OUTD END FLGD RL ILOAD (for Current Limit Response) NC GND Functional Characteristics Test Circuit MIC2524/2527 6 June 1999 MIC2524/2527 Micrel Block Diagrams FLGA OUTA ENA CHARGE PUMP GATE CONTROL CURRENT LIMIT OSC. THERMAL SHUTDOWN UVLO 1.2V REFERENCE CHARGE PUMP GATE CONTROL IN (A/B) CURRENT LIMIT ENB OUTB FLGB FLGC OUTC ENC CHARGE PUMP GATE CONTROL CURRENT LIMIT OSC. THERMAL SHUTDOWN UVLO 1.2V REFERENCE CHARGE PUMP GATE CONTROL IN (C/D) CURRENT LIMIT END OUTD FLGD MIC2527 GND June 1999 7 MIC2524/2527 MIC2524/2527 Micrel Undervoltage Lockout UVLO (undervoltage lockout) prevents the output MOSFET from turning on until VIN exceeds approximately 2.5V. In the undervoltage state, the FLAG will be low. After the switch turns on, if the voltage drops below approximately 2.3V, UVLO shuts off the output MOSFET and signals fault flag. Undervoltage detection functions only when at least one switch is enabled. Current Sensing and Limiting The current-limit threshold is preset internally. The preset level prevents damage to the output MOSFET and external load but allows a minimum current of 0.5A through the output MOSFET of each channel. Functional Description The MIC2524/7-1 and MIC2524/7-2 are quad high-side switches with active-high and active-low enable inputs, respectively. Fault conditions turn off or inhibit turn-on of one or more of the output transistors, depending upon the type of fault, and activate the open-drain error flag transistors making them sink current to ground. Input and Output IN (input) is the power supply connection to the logic circuitry and the drain of the output MOSFET. OUTx (output) is the source of its respective MOSFET. In a typical circuit, current flows through the switch from IN to OUT toward the load. If VOUT is greater than VIN, current will flow from OUT to IN since the MOSFET is bidirectional when on. The current-limit circuit senses a portion of the output FET 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: 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 output is off. In this situation, the MIC2524/7 prevents reverse current flow. If VIN < 2.5V, UVLO disables both switches. Thermal Shutdown Thermal shutdown shuts off the affected output MOSFETs and signals all fault flags if the die temperature exceeds 135°C. 10°C of hysteresis prevents the switch from turning on until the die temperature drops to 125°C. Overtemperature detection functions only when at least one switch is enabled. Current Limit Induced Thermal Shutdown Internal circuitry increases the output MOSFET on-resistance until the series combination of the MOSFET on-resistance and the load impedance limit current to typically 850mA. The increase in power dissipation, in most cases, will cause the MIC2524/7 to go into thermal shutdown, disabling affected channels. When this is undesirable, thermal shutdown can be avoided by externally responding to the fault and disabling the current limited channel before the shutdown temperature is reached. The delay between the flag indication of a current limit fault and thermal shutdown will vary with ambient temperature, board layout, and load impedance, but is typically several hundred milliseconds. The USB controller must therefore recognize a fault and disable the appropriate channel within this time. If the fault is not removed or the switch is not disabled within this time, then the device will enter into a thermal oscillation of about 2Hz. This does not cause any damage to the device. Refer to “Functional Characteristics: Thermal Shutdown Response.” MIC2524/2527 Switch Enabled into Short Circuit If a switch is powered on or enabled into a heavy load or shortcircuit, the switch immediately goes into a constant-current mode, reducing the output voltage. The fault flag goes low until the load is reduced. See the “Functional Characteristics: Short Circuit Response, Enabled into Short Circuit” photo. Short Circuit Applied to Output When a heavy load is applied, a large transient current may flow until the current limit circuitry will respond. Once this occurs, the device limits current to less than the short-circuit current limit specification. See the “Short Circuit Transient Response, Short Applied to Output” graph. Current-Limit Response The MIC2524/7 current-limit profile exhibits a small foldback effect of approximately 500mA. Once this current-limit threshold is exceeded the device enters constant-current mode. This constant current is specified as the short circuit current limit in the “Electrical Characteristics” table. It is important to note that the MIC2524/7 will deliver load current up to the current-limit threshold which is typically 1.6A. Refer to “Functional Characteristics: Current-Limit Response” photo for details. Fault Flag FLG is an N-channel, open-drain MOSFET output. The faultflag is active (low) for one or more of the following conditions: undervoltage (while 2V < VIN < 2.7), current limit, or thermal shutdown. The flag output MOSFET is capable of sinking a 10mA load to typically 100mV above ground. Multiple FLG pins may be “wire NORed” to a common pull-up resistor. 8 June 1999 MIC2524/2527 Micrel Transient Overcurrent Filter When the MIC2524/7 is enabled, large values of capacitance at the output of the device will cause inrush current to exceed the short circuit current-limit threshold of the device and assert the flag. The duration of this time will depend on the size of the output capacitance. Refer to the “Functional Characteristics” turn-on and turnoff behaviors for details. During the capacitance charging time, the device enters into constant-current mode. As the capacitance is charged, the current decreases below the short circuit current-limit threshold, and the flag will then be deasserted. In USB applications, it is required that output bulk capacitance is utilized to support hot-plug events. When the MIC2524/7 is enabled, the flag may go active for about 1ms due to inrush current exceeding the current-limit setpoint. Additionally, during hot-plug events, inrush currents may also cause the flag to go active for 30µs. Since these conditions are not valid overcurrent faults, the USB controller must ignore the flag during these events. To prevent this erroneous overcurrent reporting, a 1ms RC filter as shown in Figure 2 may be used. Alternatively, a 1ms debounce routine may be programmed into the USB logic controller, eliminating the need for the RC filter. Applications Information Supply Filtering A 0.1µF to 1µF bypass capacitor from IN to GND, located at 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. Input or output transients must not exceed the absolute maximum supply voltage (VIN max = 7V) even for a short duration. VIN 2.7V to 5.5V MIC2524/7 FLGA FLGB ENA ENB OUTA OUTB 0.1µF to 1µF GND IN 0.1µF to 1µF IN GND OUTC OUTD ENC END FLGC FLGD Figure 1. Supply Bypassing Enable Input EN must be driven logic high or logic low for a clearly defined input. Floating the input may cause unpredictable operation. EN should not be allowed to go negative with respect to GND. Soft Start The MIC2524/7 presents a high impedance when off, and slowly becomes a low impedance as it turns on. This reduces inrush current and related voltage drop that results from charging a capacitive load, satisfying the USB voltage droop requirements. June 1999 USB Controller OVERCURRENT 10k FLGA 10k 0.1µF FLGB FLGC FLGD Figure 2. Transient Filter 9 MIC2524/2527 MIC2524/2527 Micrel Package Information PIN 1 0.157 (3.99) 0.150 (3.81) DIMENSIONS: INCHES (MM) 0.020 (0.51) REF 0.050 (1.27) BSC 0.0648 (1.646) 0.0434 (1.102) 0.020 (0.51) 0.013 (0.33) 0.0098 (0.249) 0.0040 (0.102) 0.394 (10.00) 0.386 (9.80) 45° 0°–8° 0.050 (1.27) 0.016 (0.40) SEATING PLANE 0.244 (6.20) 0.228 (5.79) 16-Pin SOP (M) 0.780 MAX (19.812) PIN 1 0.030-0.110 RAD (0.762-2.794) .250±0.005 (6.350±0.127) 0.025±0.015 (0.635±0.381) 0.040 TYP (1.016) 0.130±0.005 (3.302±0.127) 0.290-0.320 (7.336-8.128) 0.020 (0.508) 0°-10° 0.020 MIN (0.508) 0.009-0.015 (0.229-0.381) 0.018±0.003 (0.457±0.076) 0.100±0.010 (2.540±0.254) 0.125 MIN (3.175) +0.025 –0.015 +0.635 8.255 –0.381 0.325 ( ) 16-Pin Plastic DIP (N) MIC2524/2527 10 June 1999 MIC2524/2527 June 1999 Micrel 11 MIC2524/2527 MIC2524/2527 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. © 1999 Micrel Incorporated MIC2524/2527 12 June 1999