19-0544; Rev 2; 6/08 100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current Features The MAX4914B/MAX4915A/B/MAX4917A/B family of switches feature internal current limiting to prevent damage to host devices due to faulty load conditions. These analog switches have a low 0.2Ω on-resistance and operate from a 2.3V to 5.5V input voltage range. They are available with guaranteed 100mA, 200mA, and 300mA current limits, making them ideal for SDIO and other load switching applications. ♦ Guaranteed Current Limit: 100mA, 200mA, 300mA When the switch is on and a load is connected to the port, a guaranteed blanking time of 14ms ensures that the transient voltages settle down. If after this blanking time the load current is greater than the current limit, the MAX4914B/MAX4915B/MAX4917B latchoff versions enter a latchoff state where the switch is turned off and FLAG is issued to the microprocessor. The switch can be turned on again by cycling the power or the ON pin. ♦ FLAG Function The MAX4915A/MAX4917A have an autoretry feature where the switch turns off after the blanking time and then continuously checks to see if the overload condition is present. The switch turns on and remains on after the overload condition disappears and FLAG deasserts. The MAX4914B is available in the tiny 6-pin µDFN (2mm x 2mm) package, while the MAX4915A/B and MAX4917A/B are available in both 6-pin µDFN (2mm x 2mm) and space-saving 5-pin SOT23 packages. These devices operate over the -40°C to +85°C extended temperature range. ♦ Thermal-Shutdown Protection ♦ Reverse Current Protection ♦ 0.2Ω On-Resistance ♦ 14ms Guaranteed Blanking Time ♦ 80µA Supply Current ♦ 8µA Latchoff Current (MAX4914B/MAX4915B/MAX4917B) ♦ Autoretry (MAX4915A/MAX4917A) ♦ 0.01µA Shutdown Current ♦ 2.3V to 5.5V Supply Range ♦ Undervoltage Lockout ♦ Fast Current-Limit Response Time (5µs) ♦ Low (0.1µA typ) Reverse Shutdown Current ♦ Tiny 6-Pin µDFN (2mm x 2mm) and 5-Pin SOT23 Packages Applications PDAs and Palmtop Devices Cell Phones GPS Systems Handheld Devices SDIO USB Ports Notebook Computers Ordering Information/Selector Guide PART MAX4914BELT+T PIN-PACKAGE TOP MARK CURRENT LIMIT (mA) RETRY/LATCH-OFF 6 µDFN ABF 100 Latchoff MAX4915AELT+T 6 µDFN ABL 200 Autoretry MAX4915AEUK+T* 5 SOT23 AEYN 200 Autoretry MAX4915BELT+T 6 µDFN ABG 200 Latchoff MAX4915BEUK+T* 5 SOT23 AEYK 200 Latchoff MAX4917AELT+T 6 µDFN ABN 300 Autoretry MAX4917AEUK+T* 5 SOT23 AEYP 300 Autoretry Latchoff MAX4917BELT+T 6 µDFN ABI 300 MAX4917BEUK+T* 5 SOT23 AEYM 300 Latchoff Note: All devices are specified over the -40°C to +85°C operating temperature range. *Future product—contact factory for availability. +Denotes a lead-free/RoHS-compliant package. T = Tape-and-reel package. Pin Configurations and Typical Operating Circuit appear at end of data sheet. ________________________________________________________________ Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX4914B/MAX4915A/B/MAX4917A/B General Description MAX4914B/MAX4915A/B/MAX4917A/B 100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current ABSOLUTE MAXIMUM RATINGS IN, ON, FLAG, OUT to GND .....................................-0.3V to +6V OUT Short Circuit to GND .................................Internally Limited Continuous Power Dissipation (TA = +70°C) 5-Pin SOT23 (derate 7.1mW/°C above +70°C)............571mW 6-Pin µDFN (derate 4.5mW/°C above +70°C)................358mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°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 = +2.3V to +5.5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VIN = +3.3V, TA = +25°C.) (Note 1) PARAMETER SYMBOL Operating Voltage VIN Quiescent Current IQ Latchoff Current (Note 2) ILATCH Forward Shutdown Current Reverse Shutdown Current ISHDN ISHDN Forward Current Limit IFWD Reverse Current Limit IREV ON Input Leakage Undervoltage Lockout CONDITIONS TYP 2.3 VON = VIN, IOUT = 0, switch on VIN = +2.3V to +5.0V 80 VIN = +5.0V to +5.5V MAX UNITS 5.5 V 120 160 VON = VIN, after an overcurrent fault MAX4914B/ MAX4915B/MAX4917B (latchoff versions) 17 µA VON = 0, VOUT = 0, VIN = +5.5V 0.01 1 µA VON = 0, VOUT = +5.5V, VIN = +2.3V 0.01 1 µA MAX4914B, VOUT = GND 100 150 MAX4915_, VOUT = GND 200 300 MAX4917_, VOUT = GND 300 450 MAX4914B, VOUT - VIN ≥ 0.5V 150 MAX4915_, VOUT - VIN ≥ 0.5V 300 MAX4917_, VOUT - VIN ≥ 0.5V 450 Rising edge -1 +1 1.75 2.25 Undervoltage-Lockout Hysteresis 100 On-Resistance RON ON Input Logic-High Voltage VIH ON Input Logic-Low Voltage VIL µA 8 VON = VIN or GND UVLO MIN TA = +25°C, IOUT = 95mA 0.2 TA = -40°C to +85°C, IOUT = 95mA 2.0 MAX4915A/MAX4917A 1.4 mA µA V mV 0.4 0.5 MAX4914B/MAX4915B/MAX4917B mA Ω V MAX4914B/MAX4915B/MAX4917B 0.8 MAX4915A/MAX4917A 0.4 FLAG Output Logic-Low Voltage ISINK = 1mA 0.4 V FLAG Output-High Leakage Current VON = VIN = V FLAG = +5.5V 1 µA Thermal Shutdown Thermal-Shutdown Hysteresis V +150 °C 15 °C 100 µs DYNAMIC CHARACTERISTICS Turn-On Time 2 VON from low to high; IOUT = 10mA, CL = 0.1µF (Note 3) _______________________________________________________________________________________ 100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current (VIN = +2.3V to +5.5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VIN = +3.3V, TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP VON from high to low; IOUT = 10mA, CL = 0.1µF (Note 3) Turn-Off Time Blanking Time tBLANK 14 ms 5 MAX4915A/MAX4917A (autoretry versions) (Figure 2) (Note 4) tRETRY ns 60 VON = VIN = +3.3V, short circuit applied to OUT Retry Time (Note 4) UNITS 40 Overcurrent fault (Figures 2, 3) Short-Circuit Current-Limit Response Time MAX µs 210 900 ms Note 1: All parts are 100% tested at +25°C. Limits across the full temperature range are guaranteed by design and correlation. Note 2: Latchoff current does not include the current flowing into FLAG. Note 3: The on-time is defined as the time taken for the current through the switch to go from 0mA to 10mA. The off-time is defined as the time taken for the current through the switch to go from 10mA to 0mA. Note 4: Retry time is typically 15 times the blanking time. Typical Operating Characteristics (VIN = 3.3V, TA = +25°C, unless otherwise noted.) 70 60 50 40 30 VON = VIN 100 20 VIN = 5V 80 60 VIN = 3.3V 40 12 VON = VIN 10 LATCHOFF CURRENT (μA) 80 120 MAX4914A/B toc02 VON = VIN QUIESCENT CURRENT (μA) QUIESCENT CURRENT (μA) MAX4914A/B toc01 100 90 LATCHOFF CURRENT vs. TEMPERATURE QUIESCENT CURRENT vs. TEMPERATURE MAX4914A/B toc03 QUIESCENT CURRENT vs. SUPPLY VOLTAGE 8 VIN = 5V 6 4 VIN = 3.3V 2 20 10 2.5 3.0 3.5 4.0 4.5 5.0 5.5 -15 10 35 60 -40 85 -15 10 35 60 TEMPERATURE (°C) TEMPERATURE (°C) FORWARD SHUTDOWN CURRENT vs. TEMPERATURE REVERSE SHUTDOWN CURRENT vs. TEMPERATURE LATCHOFF LEAKAGE CURRENT vs. TEMPERATURE VCC = 3.3V 1 0.1 0.01 -15 10 35 TEMPERATURE (°C) 60 85 MAX4914A/B toc05 ON = GND, VOUT = 5.5V VIN = 5V VIN = 3.3V 0.1 0.01 -40 100 LATCHOFF LEAKAGE CURRENT (nA) 10 1 REVERSE SHUTDOWN CURRENT (nA) MAX4914A/B toc04 VCC = 5V 100 -40 -40 SUPPLY VOLTAGE (V) 1000 FORWARD SHUTDOWN CURRENT (nA) 0 0 2.0 10 VIN = 5V 85 MAX4914A/B toc06 0 1 0.1 VIN = 3.3V 0.01 0.001 0.0001 -15 10 35 TEMPERATURE (°C) 60 85 -40 -15 10 35 60 85 TEMPERATURE (°C) _______________________________________________________________________________________ 3 MAX4914B/MAX4915A/B/MAX4917A/B ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (continued) (VIN = 3.3V, TA = +25°C, unless otherwise noted.) OUTPUT CURRENT vs. OUTPUT VOLTAGE NORMALIZED RON 1.0 0.8 0.6 0.4 450 400 350 300 250 MAX4915_ 200 150 100 0.2 100 ILOAD = 10mA ON 10 1 OFF 0.1 50 0.01 0 0 -40 -15 10 35 60 0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.3 85 TEMPERATURE (°C) VIN - VOUT (V) FLAG-BLANKING TIMEOUT vs. TEMPERATURE CURRENT-LIMIT RESPONSE (VON RISING) -40 -15 10 35 MAX4914A/B toc10 45 CIN = 0.1μF COUT = 0.1μF 60 85 TEMPERATURE (°C) CURRENT-LIMIT RESPONSE (VIN AND VON RISING TOGETHER) MAX4914A/B toc11 50 MAX4914A/B toc12 VIN 2V/div 0V VIN = VON 1V/div VON 2V/div 0V 40 35 0V 30 25 IOUT 100mA/div 20 0mA -40 -15 10 35 60 IOUT 100mA/div CIN = 0.1μF COUT = 0.1μF 20μs/div 85 20μs/div TEMPERATURE (°C) CURRENT-LIMIT RESPONSE (OUT SHORTED TO GND) TURN-ON RESPONSE MAX4914A/B toc13 MAX4914A/B toc14 VIN 2V/div 0V CIN = 1μF COUT = 0.1μF VON 1V/div VOUT 2V/div 0V 0V IOUT 50mA/div IOUT 5A/div 0A 40μs/div 4 MAX4914A/B toc09 1.2 500 MAX4914A/B toc08 VCC = 5V OUTPUT CURRENT (mA) MAX4914A/B toc07 1.4 SWITCH TURN-ON/OFF TIMES vs. TEMPERATURE SWITCH TURN-ON/OFF TIMES (μs) NORMALIZED ON-RESISTANCE vs. TEMPERATURE FLAG-BLANKING TIMEOUT (ms) MAX4914B/MAX4915A/B/MAX4917A/B 100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current CIN = 0.1μF COUT = 0.1μF 0mA 20μs/div _______________________________________________________________________________________ 0mA 100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current FLAG-BLANKING RESPONSE TURN-OFF RESPONSE MAX4914A/B toc15 MAX4914A/B toc16 CIN = 0.1μF COUT = 0.1μF VON 1V/div VIN 2V/div CIN = 0.1μF COUT = 0.1μF 0V VON 2V/div 0V 0V VFLAG 2V/div IOUT 10mA/div 0V 0mA IOUT 200mA/div 0mA 200ns/div 10ms/div Pin Description PIN MAX4915A/B/ MAX4917A/B (SOT23) MAX4914A/B/ MAX4915A/B/ MAX4917A/B (µDFN) 1 2 IN 2 5 GND 3 6 ON 4 4 FLAG Fault Output. This open-drain output goes low when the device stays in forward or reverse current limit for more than the blanking time period. FLAG is high impedance when a fault is not present or when ON is low. 5 3 OUT Switch Output. Bypass with a 0.1µF ceramic capacitor to ground as close to the device as possible. — 1 N.C. No Connection. Not internally connected. NAME FUNCTION Input. Bypass with a 0.1µF ceramic capacitor to ground as close to the device as possible. Ground Active-High, Switch-On Input. A logic-high turns the switch on. _______________________________________________________________________________________ 5 MAX4914B/MAX4915A/B/MAX4917A/B Typical Operating Characteristics (continued) (VIN = 3.3V, TA = +25°C, unless otherwise noted.) MAX4914B/MAX4915A/B/MAX4917A/B 100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current REVERSE CURRENT DETECTOR FLAG BLANKING TIME CIRCUITRY N FORWARD CURRENT DETECTOR N IN ON UNDERVOLTAGE LOCKOUT OUT +2.0V LOGIC AUTORETRY MAX4914B MAX4915A/B MAX4917A/B GND Figure 1. Functional Diagram Detailed Description The MAX4914B/MAX4915A/B/MAX4917A/B are forward/reverse current-limited switches that operate from a +2.3V to +5.5V input voltage range and guarantee a 100mA, 200mA, and 300mA minimum current-limit threshold for different options. The voltage drop across an internal sense resistor is compared to two reference voltages to indicate a forward or reverse current-limit fault. When the load current exceeds the preset current limit for greater than the fault-blanking time, the switch opens and FLAG asserts. The MAX4915A/MAX4917A have an autoretry function that turns on the switch again after an internal retry time expires. If the faulty load condition is still present after the blanking time, the switch turns off again and the cycle is repeated. If the faulty load condition is not present, the switch remains on. During this retry time, FLAG remains low until the fault is removed. The MAX4914B/MAX4915B/MAX4917B do not have the autoretry option, and the switch remains in latchoff mode until the ON pin or the input power is cycled from high to low and then high again. The undervoltage-lockout (UVLO) circuit prevents erroneous switch operation when the input voltage goes too low. 6 Reverse Current Protection All devices limit the reverse current (VOUT to VIN) from exceeding the maximum IREV value. The switch is shut off and FLAG is asserted if the reverse current-limit condition persists for more than the blanking time. This feature prevents excessive reverse currents from flowing through the device to the source. When the device is in shutdown (VON < VIL), the current from OUT to IN does not exceed 1µA (max). Switch-On/Off Control Toggle ON high to enable the current-limited switches. The switches are continuously on only if VIN exceeds the UVLO threshold (typically 2V) and there is no fault. When a forward/reverse current fault is present or the die exceeds the thermal-shutdown temperature of +150°C, OUT is internally disconnected from IN and the supply current decreases to 8µA (latchoff). The switch is now operating in one of its off states. The switch-off state also occurs when driving ON low, thus reducing the supply current (shutdown) to 0.01µA (typ). Table 1 illustrates the ON/OFF state. FLAG Indicator All devices feature a latched fault output, FLAG. Whenever a fault is activated, it latches the FLAG output low and also turns the switch off. FLAG is an open- _______________________________________________________________________________________ 100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current ON FAULT Low X OFF Shutdown High Undervoltage lockout OFF Shutdown High Thermal High SWITCH ON/OFF SUPPLY CURRENT MODE OFF immediately (tBLANK period does not apply) Latchoff OFF after tBLANK period has elapsed ON during tBLANK period, OFF during tRETRY period for the MAX4915A/MAX4917A (autoretry versions); cycle repeats until fault is removed Current limit tBLANK tRETRY tBLANK Latchoff See the Autoretry (MAX4915A/MAX4917A) section tBLANK CURRENT LIMIT SHORT CONDITION REMOVED ON SWITCH STATUS OFF FLAG STATUS Figure 2. MAX4915A/MAX4917A Autoretry Fault-Blanking Diagram drain output transistor and requires an external pullup resistor from FLAG to IN. During shutdown (VON < VIL), the pulldown on the FLAG output is released in order to limit power dissipation. FLAG goes low when any of the following conditions occur: • The die temperature exceeds the thermal-shutdown temperature limit of +150°C. • The device is in current limit for more than the faultblanking period. • VIN is below the UVLO threshold. For the MAX4915A/MAX4917A (autoretry versions), FLAG stays low until the overcurrent condition is removed (See Figure 2). Autoretry (MAX4915A/MAX4917A) When the forward or reverse current-limit threshold is exceeded, tBLANK timer begins counting (Figure 2). The timer resets if the overcurrent condition disappears before tBLANK has elapsed. A retry time delay, tRETRY, is started immediately after tBLANK has elapsed, and during that time, the switch is latched off. At the end of tRETRY, the switch is turned on again. If the fault still exists, the cycle is repeated. If the fault has been removed, the switch stays on. The autoretry feature saves system power in the case of an overcurrent or short-circuit condition. During tBLANK, when the switch is on, the supply current is at the current limit. During tRETRY, when the switch is off, the current through the switch is zero. Instead of observing the full load current, the switch sees the equivalent load current times duty cycle or ISUPPLY = I LOAD ✕ t BLANK / (t BLANK + t RETRY ). With a typical tBLANK = 37ms and typical tRETRY = 555ms, the duty cycle is 6%, which results in a 94% power savings over the switch being on the entire time. The duty cycle is consistent across the process and devices. _______________________________________________________________________________________ 7 MAX4914B/MAX4915A/B/MAX4917A/B Table 1. MAX4914B/MAX4915A/B/MAX4917A/B Switch Truth Table MAX4914B/MAX4915A/B/MAX4917A/B 100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current tBLANK FIGURE 3a device to enter current limit, an internal counter starts. If the load-transient fault persists beyond the fault-blanking timeout, FLAG asserts low. Load-transient faults less than tBLANK do not cause a FLAG output assertion. Only current-limit faults are blanked. tBLANK LOAD CURRENT A thermal fault and input voltage drops below the UVLO threshold cause FLAG to assert immediately and not wait for the blanking time. ON SWITCH STATUS OFF Thermal Shutdown The MAX4914B/MAX4915A/B/MAX4917A/B have a thermal-shutdown feature to protect the devices from overheating. The switch turns off and FLAG goes low immediately (no fault blanking) when the junction temperature exceeds +150°C. The switch turns back on when the device temperature drops approximately by 15°C. ON PIN VOLTAGE FLAG PIN STATUS Applications Information FIGURE 3b tBLANK tBLANK Input Capacitor LOAD CURRENT To limit the input-voltage drop during momentary output short-circuit conditions, connect a capacitor from IN to GND. A 0.1µF ceramic capacitor is adequate for most applications; however, higher capacitor values further reduce the voltage drop at the input and are recommended for lower voltage applications. ON SWITCH STATUS IN PIN VOLTAGE OFF UVLO Output Capacitance FLAG PIN STATUS Figure 3. MAX4914B/MAX4915B/MAX4917B Latchoff Fault Blanking Latchoff (MAX4914B/MAX4915B/MAX4917B) When the forward or reverse current-limit threshold is exceeded, the tBLANK timer begins counting. The timer resets if the overcurrent condition disappears before tBLANK has elapsed. The switch is shut off if the overcurrent condition continues up to the end of the blanking time. Reset the switch by either toggling ON (Figure 3a) or cycling the input voltage below UVLO, typically 2V (Figure 3b). Fault Blanking All devices feature 14ms (min) 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 8 Connect a 0.1µF capacitor from OUT to GND. This capacitor helps prevent inductive parasitics from pulling OUT negative during turn-off, thus preventing the devices from tripping erroneously. If the load capacitance is too large, the current may not have enough time to charge the capacitance and the device assumes that there is a faulty load condition. The maximum capacitive load value that can be driven from OUT is obtained by the following formula: CMAX < IFWD _ MIN × tBLANK _ MIN VIN 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 as possible to the device (no more than 5mm). IN and OUT pins must be connected with short traces to the power bus. During normal operation, the power dissipation is small and the package temperature change is minimal. If the output is continuously shorted to ground at the maximum _______________________________________________________________________________________ 100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current PMAX = VIN _ MAX × IOUT _ MAX × tBLANK tRETRY + tBLANK = 155mW Attention must be given to the MAX4914B/MAX4915B/ MAX4917B (latchoff versions), where the latchoff condition must be manually reset by toggling ON from high to low. If the latchoff time duration is not sufficiently high, it is possible for the device to reach the thermalshutdown threshold and never be able to turn the device on until it cools down. where VIN = 5.5V, IOUT = 450mA, tBLANK = 14ms, and tRETRY = 210ms. Pin Configurations TOP VIEW + + IN 1 GND 2 5 OUT N.C. 1 MAX4915A/B MAX4917A/B IN 2 4 FLAG ON 3 OUT 3 6 ON MAX4914B 5 GND MAX4915A/B MAX4917A/B 4 FLAG μDFN (2mm x 2mm) SOT23 Typical Operating Circuit 2.3V TO 5.5V IN ON MAX4914B FLAG MAX4915A/B MAX4917A/B μP TO SDIO PORT OUT GND Chip Information PROCESS: BiCMOS _______________________________________________________________________________________ 9 MAX4914B/MAX4915A/B/MAX4917A/B supply voltage, the operation of the switches with the autoretry option does not cause problems because the total power dissipated during the short is scaled by the duty cycle: MAX4914B/MAX4915A/B/MAX4917A/B 100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current Package Information For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. 10 PACKAGE TYPE PACKAGE CODE DOCUMENT NO. 6 µDFN L622-1 21-0164 5 SOT23 U5-2 21-0057 ______________________________________________________________________________________ 100mA/200mA/300mA Current-Limit Switches with Low Shutdown Reverse Current REVISION NUMBER REVISION DATE 0 5/06 Initial release — 1 12/06 Removed future product notes. Added new VIH and VIL EC table specs for the MAX4915 — 2 6/08 Changed VIH and VIL EC table specs for the MAX4917A 2 DESCRIPTION PAGES CHANGED 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 ____________________ 11 © 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc. MAX4914B/MAX4915A/B/MAX4917A/B Revision History