19-1518; Rev 2; 9/01 USB Current-Limited Switches with Fault Blanking A fault signal notifies the microprocessor that the internal current limit has been reached. A 10ms fault-blanking feature allows momentary faults (such as those caused when hot-swapping into a capacitive load) to be ignored, thus preventing false alarms to the host system. This fault blanking also prevents a fault signal from being issued when the device is powering up. In the MAX1693/(MAX1693H), an output overcurrent condition causes the switch to current limit at 0.7A to 1.0A and FAULT to go low after the 10ms blanking period. When the overcurrent condition is removed, FAULT returns to its high-impedance state. In the MAX1694, any overcurrent longer than 10ms will latch the switch open and set FAULT low. The latch is cleared by cycling the ON input or by powering up the device again. This feature saves power by preventing the device from thermally cycling on and off in case of a persistent short-circuit condition. The MAX1693/(MAX1693H)/MAX1694 have several safety features to ensure that the USB port is protected. Built-in thermal-overload protection limits power dissipation and junction temperatures. All devices have accurate internal current-limiting circuitry to protect the input supply against overload. They are available in space-saving 10-pin µMAX packages. Features ♦ Accurate Current Limit (0.7A min, 1.0A max) ♦ Guaranteed 0.75A Short-Circuit Protection ♦ 10ms Internal Fault-Blanking Timeout ♦ No Fault Signal During Power-Up ♦ Latched FAULT Output Turns Off Power Switch (MAX1694) ♦ Thermal Shutdown Protection ♦ 2.7V to 5.5V Supply Range ♦ 14µA Supply Current ♦ Small 10-Pin µMAX Package ♦ UL Recognized–#E211935 Applications USB Ports and Hubs Notebook Computers Portable Equipment Docking Stations Hot Plug-In Power Supplies Battery-Charger Circuits Ordering Information PART TEMP RANGE MAX1693EUB MAX1693HEUB MAX1694EUB -40°C to +85°C -40°C to +85°C -40°C to +85°C Typical Operating Circuit Pin Configuration INPUT 2.7V TO 5.5V TOP VIEW IN 1 OUT 2 IN 3 OUT 4 (ON) ON 5 IN µMAX 9 IN 8 OUT 7 FAULT 6 GND OUT OUTPUT MAX1693 (MAX1693H) MAX1694 10 OUT MAX1693 (MAX1693H) MAX1694 PIN-PACKAGE 10 µMAX 10 µMAX 10 µMAX FAULT (ON) OFF ON (OFF) ON (ON) GND _______________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX1693/(MAX1693H)/MAX1694 General Description The MAX1693/(MAX1693H)/MAX1694 are current-limited, 60mΩ switches with built-in fault blanking. Their accurate preset current limit of 0.7A to 1.0A makes them ideally suited for USB applications. Their low quiescent supply current (14µA) and shutdown current (1µA) conserve battery power in portable applications. The MAX1693/(MAX1693H)/MAX1694 operate with inputs from 2.7V to 5.5V, making them ideal for both 3V and 5V systems. MAX1693/(MAX1693H)/MAX1694 USB Current-Limited Switches with Fault Blanking ABSOLUTE MAXIMUM RATINGS IN, ON (ON), FAULT to GND....................................-0.3V to +6V OUT to GND ................................................-0.3V to (VIN + 0.3V) Maximum Continuous Switch Current .....1.2A (internally limited) OUT Short Circuit to GND ..........................................Continuous Continuous Power Dissipation (TA = +70°C) 10-Pin µMAX (derate 5.6mW/°C above +70°C) ............444mW Operating Temperature Range MAX1693EUB/MAX1693HEUB/ MAX1694EUB ..................................................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (VIN = +5V, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER Operating Voltage Quiescent Current SYMBOL VIN IQ Off-Supply Current Undervoltage Lockout Current Limit RON ILIMIT Timer not running 14 Timer running 35 Rising edge, 100mV hysteresis V ON (ON) = VIN (GND) VIN = 5.5V, VOUT = GND TA = +25°C TA = +25°C VIN = 4.4V to 5.5V TA = 0°C to +85°C (Note 1) VIN = 2.7V to 5.5V FAULT Output High Leakage Current Fault-Blanking Timeout Period tFB 700 VIN = 2.7V to 3.6V 2 VIN = 3.7V to 5.5V 2.4 V 25 µA 1 µA 2.6 V 2 90 mΩ 72 150 850 1000 mA 500 700 mA 0.8 V V V ON (ON) = VIN or GND ±1 µA ISINK = 1mA, VIN = 3V 0.4 V 1 µA 13 ms From overcurrent condition to FAULT assertion 7 10 VIN = 5V, COUT = 150µF, RL = 15Ω, from ON (ON) driven low (high) to 50% full VOUT 1 80 200 6 20 Switch Turn-On Time tON ILOAD = 400mA Switch Turn-Off Time tOFF ILOAD = 400mA 2 5.5 125 VIN = V FAULT = 5.5V Start-Up Time Thermal Shutdown Threshold 60 VIN = 3V VIL VOL UNITS 15 VIN = 4.4V to 5.5V ON (ON) Input Logic Low Voltage FAULT Output Logic Low Voltage 0.01 MAX µA ISC ON (ON) Input Leakage 0.001 2.0 TA = 0°C to +85°C OUT shorted to GND, MAX1693/(MAX1693H) only (Note 2) VIH TYP 2.7 V ON (ON) = GND (VIN) IOUT = 0 Continuous Short-Circuit Current Limit ON (ON) Input Logic High Voltage MIN V ON (ON) = VIN = VOUT = 5.5V (VON = GND) UVLO Off-Switch Leakage On-Resistance CONDITIONS 3 165 _______________________________________________________________________________________ ms µs µs °C USB Current-Limited Switches with Fault Blanking MAX1693/(MAX1693H)/MAX1694 ELECTRICAL CHARACTERISTICS (VIN = +5V, TA = -40°C to +85°C, unless otherwise noted.) (Note 3) PARAMETER SYMBOL Operating Voltage VIN Quiescent Current IQ Off-Supply Current Undervoltage Lockout UVLO Off-Switch Leakage On-Resistance RON Current Limit ILIMIT Continuous Short-Circuit Current Limit ON (ON) Input Logic Low Voltage ON (ON) Input Logic High Voltage MIN MAX UNITS 5.5 V V ON (ON) = GND (GND), IOUT = 0, timer not running 25 µA V ON (ON) = VIN = VOUT = 5.5V (VON = GND) 2 µA 3 Rising edge, 100mV hysteresis 2.9 V 15 µA VIN = 4.4V to 5.5V 125 VIN = 3V 150 (Note 1) 2.0 VIL VIH VOL FAULT Output High Leakage Current TYP V ON (ON) = VIN = 5.5V, VOUT = GND (VON = GND) 640 OUT shorted to GND, MAX1693/(MAX1693H) only (Note 2) ON (ON) Input Leakage FAULT Output Logic Low Voltage CONDITIONS VIN = 3V to 5.5V VIN = 3V to 3.6V VIN = 3.7V to 5.5V mΩ 1060 mA 750 mA 0.8 V 2 V 2.4 V ON (ON) = VIN or GND ±1 µA ISINK = 1mA, VIN = 3V 0.4 V 1 µA VIN = V FAULT = 5.5V Fault-Blanking Timeout Period tFB From overcurrent condition to FAULT assertion Switch Turn-On Time tON ILOAD = 400mA Switch Turn-Off Time tOFF ILOAD = 400mA 6 1 14 ms 200 µs 20 µs Note 1: MAX1693/(MAX1693H)’s current limit is tested by forcing VOUT to 4.5V. The MAX1694’s current limit is tested by increasing the output current until the switch is latched off. Note 2: This specification applies to the MAX1693/(MAX1693H) only. The MAX1694 latches the switch off under a sustained (>10ms) short-circuit condition. Note 3: Specifications to -40°C are guaranteed by design, not production tested. _______________________________________________________________________________________ 3 Typical Operating Characteristics (VIN = +5V, TA = +25°C, unless otherwise noted.) 8 6 4 VON (ON) = VIN (GND) OFF-SUPPLY CURRENT (nA) 10 14 VIN = 3V 13 12 11 10 1 0.1 10 0.01 9 1 2 3 4 5 -40 6 -20 0 20 40 60 80 INPUT VOLTAGE (V) TEMPERATURE (°C) OFF-SWITCH CURRENT vs. TEMPERATURE NORMALIZED ON-RESISTANCE vs. TEMPERATURE V0N (ON) = VIN (GND) IOUT = 425mA 1.2 NORMALIZED RON 100 10 1 0.8 0.6 0.4 0.1 0.2 -20 20 0 60 40 80 -20 0 20 40 60 80 0.8 SHORT-CIRCUIT CURRENT 0.6 0.4 0.2 0 100 1 2 3 4 OUTPUT VOLTAGE (V) TURN-ON TIME vs. TEMPERATURE TURN-OFF TIME vs. TEMPERATURE ILOAD = 425mA VIN = 3V 120 7 MAX1693/4 toc07 160 ILOAD = 425mA VIN = 5V 6 80 VIN = 5V 60 tOFF (µs) 5 100 tON (µs) ILIMIT TEMPERATURE (°C) TEMPERATURE (°C) 140 4 VIN = 3V 3 2 40 1 20 0 0 -40 -20 0 20 40 60 TEMPERATURE (°C) 80 100 0 -40 100 80 1.0 0 -40 0 20 40 60 TEMPERATURE (°C) 1.2 1.0 0.01 -20 NORMALIZED OUTPUT CURRENT vs. OUTPUT VOLTAGE 1.4 MAX1693/4 toc04 1000 -40 100 MAX1693/4 toc06 0 NORMALIZED OUTPUT CURRENT 0 MAX1693/4 toc08 2 4 MAX1693/4 toc03 MAX1693/4 toc02 15 12 100 MAX1693/4 toc05 QUIESCENT CURRENT (µA) VIN = 5V QUIESCENT CURRENT (µA) VON (ON) = GND (VIN) IOUT = O 14 16 MAX1693/4 toc01 16 OFF-SUPPLY CURRENT vs. TEMPERATURE QUIESCENT CURRENT vs. TEMPERATURE QUIESCENT CURRENT vs. INPUT VOLTAGE OFF-SWITCH CURRENT (nA) MAX1693/(MAX1693H)/MAX1694 USB Current-Limited Switches with Fault Blanking 100 -40 -20 0 20 40 60 TEMPERATURE (°C) _______________________________________________________________________________________ 80 100 5 6 USB Current-Limited Switches with Fault Blanking MAX1693 CURRENT-LIMIT AND FAULT RESPONSE 10 8 1 MAX1693/4 toc11 MAX1693/4 toc09 1 2 2 3 3 4 4 6 4 2 IOUT = 850mA VIN = 3V OR 5V 0 -40 -20 0 20 40 60 80 100 TEMPERATURE (°C) MAX1693 SWITCH TURN-ON TIME 2ms/div 10µs/div CH1 = VIN, 200mV/div, AC-COUPLED; CH2 = VOUT, 5V/div; CH3 = VFAULT, 5V/div; CH4 = IOUT, 500mA/div CH1 = VIN, 200mV/div, AC-COUPLED; CH2 = VOUT, 5V/div; CH3 = VFAULT, 5V/div; CH4 = IOUT, 1A/div MAX1693 STARTUP TIME (TYPICAL USB APPLICATION) MAX1693/4 toc13 MAX1693/4 toc12 MAX1693 SWITCH TURN-OFF TIME 1 1 2 2 3 3 1 4 FULL-CURRENT LIMIT CHARGES CAPACITOR CL = 150µF RL = 15Ω 2 3 MAX1693/4 toc14 FAULT-BLANKING TIMEOUT (ms) 12 MAX1693 CURRENT-LIMIT RESPONSE MAX1693/4 toc10 FAULT-BLANKING TIMEOUT vs. TEMPERATURE FOLDBACKCURRENT LIMIT RESISTOR LOAD CURRENT 4 4 20µs/div CH1 = VOUT, 5V/div; CH2 = VON, 5V/div; CH3 = VFAULT, 5V/div; CH4 = IOUT, 200mA/div 1µs/div CH1 = VOUT, 5V/div; CH2 = VON, 5V/div; CH3 = VFAULT, 5V/div; CH4 = IOUT, 200mA/div 1ms/div CH1 = VOUT, 5V/div; CH2 = VON, 5V/div; CH3 = IOUT, 500mA/div; CH4 = VFAULT, 5V/div _______________________________________________________________________________________ 5 MAX1693/(MAX1693H)/MAX1694 Typical Operating Characteristics (continued) (VIN = +5V, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VIN = +5V, TA = +25°C, unless otherwise noted.) MAX1694 OVERCURRENT TO FAULT AND SWITCH LATCHED OFF 1 MAX1693/4 toc16 MAX1693/4 toc15 MAX1693H SWITCH TURN-ON TIME 1 2 2 3 3 4 20ms/div 2ms/div CH1 = VOUT, 5V/div; CH2 = VON, 5V/div; CH3 = VFAULT, 5V/div; CH4 = IOUT, 200mA/div CH1 = VFAULT, 5V/div; CH2 = IOUT, 5V/div; CH3 = IOUT, 1A/div 1 FULL-CURRENT LIMIT CHARGES CAPACITOR 1 CL = 150µF RL = 15Ω 2 2 3 3 FOLDBACKCURRENT LIMIT RESISTOR LOAD CURRENT 4 4 1ms/div CH1 = VOUT, 5V/div; CH2 = VON, 5V/div; CH3 = VFAULT, 5V/div; CH4 = IOUT, 200mA/div 6 1ms/div CH1 = VOUT, 5V/div; CH2 = VON, 5V/div; CH3 = IOUT, 500mA/div; CH4 = VFAULT, 5V/div _______________________________________________________________________________________ MAX1693/4 toc18 MAX1693H STARTUP TIME (TYPICAL USB APPLICATION) MAX1693H SWITCH TURN-OFF TIME MAX1693/4 toc17 MAX1693/(MAX1693H)/MAX1694 USB Current-Limited Switches with Fault Blanking USB Current-Limited Switches with Fault Blanking PIN NAME FUNCTION Input. P-channel MOSFET source. Connect all IN pins together and bypass with a 1µF ceramic capacitor to ground. 1, 3, 9 IN 2, 4, 8, 10 OUT 5 ON (ON) 6 GND Switch Output. P-channel MOSFET drain. Connect all OUT pins together and bypass with a 0.1µF capacitor to ground. Active-Low (High) Switch On Input. A logic low (high) turns the switch on. Ground Fault-Indicator Output. This open-drain output goes low when the device is in thermal shutdown, undervoltage lockout, or on a sustained (>10ms) current-limit condition. For the MAX1694 only, this output latches low when asserted, and the power switch is turned off until the latch is reset. FAULT 7 These switches are not bidirectional; therefore, the input voltage must be higher than the output voltage. P IN OUT P FAULT N Continuous Short-Circuit Protection MAX1693 (MAX1693H) The MAX1693/(MAX1693H)/MAX1694 are foldback short circuit-protected switches. In the event of an output short-circuit or current-overload condition, the current through the switch is foldback-current limited to 500mA continuous for the MAX1693. For the MAX1694, if the short circuit lasts longer than 10ms, the switch is latched off. REPLICA AMPLIFIER ON P Thermal Shutdown ON 10ms TIMER CURRENT-LIMIT AMPLIFIER 1.24V HOT GND ON (ON) CONTROL CIRCUITRY Figure 1. MAX1693 Functional Diagram _______________Detailed Description The MAX1693/(MAX1693H)/MAX1694 P-channel MOSFET power switches limit output current to 0.7A min to 1.0A max. When the output current is increased beyond the current limit (I LIMIT ), the current also increases through the replica switch (IOUT/6500). The current-limit error amplifier compares the voltage to the internal 1.24V reference and regulates the current back to the ILIMIT. The MAX1693/(MAX1693H)/MAX1694 feature thermal shutdown. The switch turns off and the FAULT output goes low immediately (no fault blanking) when the junction temperature exceeds +165°C. The MAX1694 remains latched with the switch off and the FAULT output low. When the MAX1693/(MAX1693H) cools 20°C, the switch turns back on. If the fault short-circuit condition is not removed, the switch will cycle on and off, resulting in a pulsed output. FAULT Indicator The MAX1693/(MAX1693H)/MAX1694 provide a fault output (FAULT). A 100kΩ pullup resistor from FAULT to IN provides a logic control signal. This open-drain output goes low when any of the following conditions occur: • The input voltage is below the undervoltage-lockout (UVLO) threshold. • The die temperature exceeds the thermal shutdown temperature limit of +165°C. • The device is in current limit and the 10ms faultblanking period is exceeded. _______________________________________________________________________________________ 7 MAX1693/(MAX1693H)/MAX1694 Pin Description MAX1693/(MAX1693H)/MAX1694 USB Current-Limited Switches with Fault Blanking Fault Blanking Output Capacitor The MAX1693/(MAX1693H)/MAX1694 feature 10ms fault blanking. Fault blanking allows current-limit faults, including momentary short-circuit faults that occur when hot-swapping a capacitive load, and also ensures that no fault is issued during power-up. When a load transient causes the device to enter current limit, an internal counter starts. If the load fault persists beyond the 10ms fault-blanking timeout, the FAULT output asserts low. Ensure that the MAX1693/(MAX1693H)/ MAX1694’s input is adequately bypassed to prevent input glitches from triggering spurious FAULT outputs. Input voltage glitches less than 150mV will not cause a spurious FAULT output. Load-transient faults less than 10ms (typ) will not cause a FAULT output assertion. Only current-limit faults are blanked. Die overtemperature faults and input voltage droops below the UVLO threshold will cause an immediate fault output. Connect a 0.1µF capacitor from OUT to GND. This capacitor helps prevent inductive parasitics from pulling OUT negative during turn-off. Fault Latching (MAX1694 Only) The MAX1694 features a latched FAULT output. Whenever the FAULT output is activated, it latches the FAULT output low and also turns the switch off. To clear the latch, either cycle the ON input or cycle the input voltage below UVLO. Applications Information Input Capacitor To limit the input voltage drop during momentary output short-circuit conditions, connect a capacitor from IN to GND. A 1µF ceramic capacitor will be adequate for most applications; however, higher capacitor values will further reduce the voltage drop at the input (see Figure 2). Layout and Thermal Dissipation To optimize the switch-response time to output shortcircuit conditions, it is very important to keep all traces as short as possible to reduce the effect of undesirable parasitic inductance. Place input and output capacitors as close to the device as possible (no more than 5mm). All IN and all OUT pins must be connected with short traces to the power bus. Wide power bus planes will provide superior heat dissipation through the switch IN and OUT pins. Figure 3 shows suggested pin connections for a single-layer board. Under normal operating conditions, the package can dissipate and channel heat away. Calculate the maximum power dissipation as follows: P = (ILIMIT)2 ✕ RON where ILIMIT is the preset current limit (1.0A max) and RON is the on-resistance of the switch (125mΩ max). When the output is short-circuited, foldback-current limiting activates and the voltage drop across the switch equals the input supply. The power dissipated across the switch increases, as does the die temperature. If the fault condition is not removed, the thermal-overload-protection circuitry activates (see the Thermal Shutdown section). Wide power-bus planes connected to IN and OUT and a ground plane in contact with the device will help dissipate additional heat. Chip Information TRANSISTOR COUNT: 715 INPUT 2.7V TO 5.5V IN OUT 1µF MAX1693 (MAX1693H) MAX1694 OUTPUT 0.1µF* MAX1693 (MAX1693H) MAX1694 100k FAULT (ON) OFF ON (OFF) ON (ON) GND 1 IN 2 OUT 3 IN 4 OUT 5 ON (ON) OUT 10 IN 9 OUT 8 FAULT 7 GND 6 *USB SPECIFICATIONS REQUIRE A LARGER CAPACITOR Figure 2. Typical Application Circuit Figure 3. IN and OUT Cross Connections for a Single-Layer Board 8 ________________________________________________________________________________________ USB Current-Limited Switches with Fault Blanking 10LUMAX.EPS Note: Neither the MAX1693/(MAX1693H) nor MAX1694 has an exposed pad. Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 9 © 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. MAX1693/(MAX1693H)/MAX1694 Package Information