19-0552; Rev 3; 6/08 Overvoltage-Protection Controllers with Internal FET Features The MAX4943-MAX4946/MAX4949 family of overvoltage-protection devices feature a low 80m (typ) RON internal FET and protect low-voltage systems against voltage faults up to +28V. These devices also drive an optional external pFET to protect down to -28V when connected to a load with reverse current protection. When the input voltage exceeds the overvoltage threshold, the internal FET is turned off to prevent damage to the protected components. Input Voltage Protection Up to +28V All switches feature a minimum 1.2A current-limit protection. During a short-circuit occurrence, the MAX4944B and MAX4945B place the switch in a latchoff state where the switch turns off and remains off. For the autoretry devices, the switch turns off and continuously checks after a 15ms (typ) retry time. Low-Current Undervoltage-Lockout Mode Integrated nFET Switch Preset Overvoltage Protection Trip Level 7.40V (MAX4943) 6.35V (MAX4944_) 5.80V (MAX4945_) 4.56V (MAX4946) 8.90V (MAX4949) Short-Circuit Protection (Latchoff/Autoretry) Internal 15ms (typ) Startup Delay and Retry Times Input Voltage Power-Good Logic Output Thermal-Shutdown Protection The overvoltage thresholds (OVLO) are preset to 7.4V, 6.35V, 5.8V, 4.56V, or 8.9V. The undervoltage-lockout (UVLO) thresholds are preset to 2.45V and 4.15V. When the input voltage drops below the undervoltagelockout (UVLO) threshold, the devices enter a lowcurrent standby mode. (See the Ordering Information/ Selector Guide for more details on UVLO/OVLO). All devices are offered in a small, 8-pin DFN (2mm x 2mm) package and are specified for operation over the -40C to +85C temperature range. Small, 8-Pin (2mm x 2mm) DFN Package Pin Configuration TOP VIEW + IN 1 IN 2 GP 3 Applications Cell Phones PDAs and Palmtop Devices Digital Still Cameras MP3 Players ACOK 4 8 OUT MAX4943- MAX4946/ MAX4944L/ MAX4945A/ MAX4945L/ MAX4949 7 OUT 6 OUT 5 GND DFN 2mm x 2mm Ordering Information/Selector Guide PART MAX4943ELA+T* PIN-PACKAGE TOP MARK PKG CODE UVLO (V) OVLO (V) OVERCURRENT MODE 8 DFN ABA L822-1 4.15 7.40 Retry MAX4944ELA+T 8 DFN ABB L822-1 4.15 6.35 Retry MAX4944BELA+T* 8 DFN ABC L822-1 4.15 6.35 Latchoff MAX4944LELA+T 8 DFN ABD L822-1 2.45 6.35 Retry MAX4945ELA+T** 8 DFN ABE L822-1 4.15 5.80 Retry MAX4945AELA+T** 8 DFN ADW L822-1 4.15 5.80 Retry MAX4945BELA+T* 8 DFN ABF L822-1 4.15 5.80 Latchoff MAX4945LELA+T 8 DFN ABG L822-1 2.45 5.80 Retry MAX4946ELA+T 8 DFN ABH L822-1 2.45 4.56 Retry MAX4949ELA+T 8 DFN ADT L822-1 2.45 8.90 Latchoff Note: All devices are specified over the -40C to +85C operating temperature range. +Denotes a lead-free/RoHS-compliant package. T = Tape-and-reel package. *Future product--contact factory for availability. **The OVLO is 6.10V (max) for the MAX4945ELA+T and .6.0V (max) for the MAX4945AELA+T. ________________________________________________________________ Maxim Integrated Products 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. 1 MAX4943-MAX4946/MAX4944L/MAX4945A/MAX4945L/MAX4949 General Description MAX4943-MAX4946/MAX4944L/MAX4945A/MAX4945L/MAX4949 Overvoltage-Protection Controllers with Internal FET ABSOLUTE MAXIMUM RATINGS IN ............................................................................-0.3V to +30V OUT ...............................................................-0.3V to (IN + 0.3V) GP...........................................................................-0.3V to +12V IN to GP ..................................................................-0.3V to +22V ACOK .......................................................................-0.3V to +6V Continuous Power Dissipation (TA = +70C) 8-Pin DFN (derate 4.8mW/C above +70C) ..............381mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C 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 (MAX4943/MAX4944_/MAX4945_/MAX4949), VIN = +3V (MAX4946), TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1) PARAMETER Input Voltage Range SYMBOL Input Supply Current IIN UVLO Supply Current IUVLO IN Undervoltage Lockout CONDITIONS VIN VUVLO MIN VIN = 5V, all remaining parts 50 150 VIN = 2.2V (VIN falling) 30 MAX4943/MAX4944/ MAX4944B/MAX4945/ MAX4945A/ MAX4945B 3.90 MAX4944L/MAX4945L/ MAX4946/MAX4949 2.30 4.15 VOVLO (VIN rising) 2.45 2.60 % MAX4943 7.00 7.4 7.80 MAX4944_ 6.00 6.35 6.70 MAX4945/MAX4945B/L 5.50 5.80 6.10 MAX4945A 5.50 5.80 6.00 MAX4946 4.30 4.56 4.82 MAX4949 8.20 8.90 9.60 GP Clamp Voltage IGPD GP Pulldown Resistor RGPD 80 200 VIN = 5V, all remaining parts, IOUT = 1A 80 200 (VIN - VGP), VIN = 28V TA = +25C 1.2 1.7 4.0 TA = TMIN to TMAX 1.2 1.7 4.0 TA = +25C 2.0 3.5 5.0 TA = TMIN to TMAX 2.0 3.0 5.0 16 19 13 50 _______________________________________________________________________________________ V % VIN = 3V (MAX4946), IOUT = 1A ILIM A V 1 RON A 4.40 1 MAX4949 2 V 150 MAX4943-MAX4946 Overcurrent Protection Threshold UNITS 28.0 50 IN Overvoltage Hysteresis Switch On-Resistance MAX VIN = 3V (MAX4946) IN Undervoltage-Lockout Hysteresis Overvoltage Trip Level TYP 2.2 m A V k Overvoltage-Protection Controllers with Internal FET (VIN = +5V (MAX4943/MAX4944_/MAX4945_/MAX4949), VIN = +3V (MAX4946), TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1) PARAMETER SYMBOL ACOK Output-Low Voltage VOL CONDITIONS MIN TYP ISINK = 1mA ACOK High-Leakage Current V ACOK = 5.5V Thermal Shutdown Thermal-Shutdown Hysteresis MAX UNITS 0.4 V 1 A +175 C 40 C Load Capacitor 300 F TIMING CHARACTERISTICS (Figure 2) tINDBC Time from VUVLO < VIN < VOVLO to chargepump enable 15 ms Switch Turn-On Time tON VUVLO < VIN < VOVLO, RLOAD = 100, CLOAD = 300F, VOUT = from 10% of VOUT to 80% of VOUT 6 ms ACOK Assertion Time t ACOK VUVLO < VIN < VOVLO, to ACOK low 30 ms Switch Turn-Off Time tOFF VIN < VUVLO or VIN > VOVLO, to internal switch off 2 Overcurrent fault to internal switch turn-off 10 s From overcurrent fault to internal switch turn-on 15 ms Debounce Time Autoretry Time tRETRY 20 s Note 1: All specifications are 100% production tested at TA = +25C, unless otherwise noted. Specifications are over -40C to +85C and are guaranteed by design. Typical Operating Characteristics (TA = +25C, unless otherwise noted.) SUPPLY CURRENT vs. SUPPLY VOLTAGE 100 210 RON (m) 180 150 120 90 80 60 40 60 20 30 2 6 10 14 18 SUPPLY VOLTAGE (V) 22 26 1.008 1.006 1.004 1.002 1.000 0.998 0.996 0.994 0.992 0 0 MAX4943 toc03 120 1.010 NORMALIZED UVLO THRESHOLD MAX4943 toc02 MAX4944 240 SUPPLY CURRENT (nA) 140 MAX4943 toc01 300 270 NORMALIZED UVLO THRESHOLD vs. TEMPERATURE RON vs. TEMPERATURE 0.990 -40 -15 10 35 TEMPERATURE (C) 60 85 -40 -15 10 35 60 85 TEMPERATURE (C) _______________________________________________________________________________________ 3 MAX4943-MAX4946/MAX4944L/MAX4945A/MAX4945L/MAX4949 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (continued) (TA = +25C, unless otherwise noted.) 1.004 1.002 1.000 0.998 0.996 36 34 MAX4943 toc06 38 23 21 19 17 32 0.994 25 DEBOUNCE TIME (ms) 1.006 40 MAX4943 toc05 1.008 ACOK ASSERTION TIME (ms) MAX4943 toc04 1.010 DEBOUNCE TIME vs. TEMPERATURE ACOK ASSERTION TIME vs. TEMPERATURE NORMALIZED OVLO THRESHOLD vs. TEMPERATURE NORMALIZED OVLO THRESHOLD MAX4943-MAX4946/MAX4944L/MAX4945A/MAX4945L/MAX4949 Overvoltage-Protection Controllers with Internal FET 0.992 15 30 0.990 -40 -15 10 35 60 -40 85 -15 10 35 60 85 -40 POWER-UP RESPONSE -15 10 35 TEMPERATURE (C) TEMPERATURE (C) TEMPERATURE (C) UNDERVOLTAGE FAULT RESPONSE MAX4943 toc07 MAX4943 toc08 5V ADAPTER 5V/div 3V ADAPTER 2V/div 5V VIN 5V/div VIN 3V 2V/div VOUT 5V/div VOUT 0 5V/div VACOK 5V/div 0 IOUT 2A/div 10ms/div IOUT 0 1A/div 4s/div OVERCURRENT DURATION TIME (DURING AUTORETRY) SHORT-CIRCUIT FAULT RESPONSE MAX4943 toc09 MAX4943 toc10 RLOAD = 1 COUT = 0.1F ADAPTER 2V/div VOUT 1V/div VIN 5V/div VOUT 5V/div VACOK 5V/div CIN = 1000F 1s/div 4 VACOK 5V/div IOUT 1A/div IOUT 10A/div 10s/div _______________________________________________________________________________________ 60 85 Overvoltage-Protection Controllers with Internal FET PIN NAME FUNCTION 1, 2 IN Voltage Input. IN powers the charge pump required to turn on the internal switch. When the correct adapter is plugged in, a 15ms (typ) debouncer prevents false turn-on of the internal switch. Bypass IN to GND with a 1F ceramic capacitor as close as possible to the device to enable 15kV (HBM) ESD protection on IN. 3 GP pFET Gate-Drive Output. GP pulls the external pFET gate down when the input is above ground. 4 ACOK 5 GND Ground 6, 7, 8 OUT Output Voltage. Output of internal switch. Short all pins together for proper operation. Active-Low Open-Drain Adapter-Voltage Indicator Output. ACOK is driven low after the adapter voltage is stable between VUVLO and VOVLO for 30ms (typ). Connect a pullup resistor from ACOK to the logic I/O voltage of the host system. OUT IN CHARGE PUMP GP CHARGE-PUMP ENABLED GND 15ms (typ) DEBOUNCE TIMER AND RETRY TIME + VOVLO - RESET OVERCURRENT OR THERMAL FAULTS OSCILLATOR VUVLO + - RESET 30ms (typ) TIMER ACOK MAX4943-MAX4946/MAX4944L/ MAX4945L/MAX4949 Figure 1. Functional Diagram Detailed Description The MAX4943-MAX4946/MAX4949 overvoltage-protection devices feature a low RON internal FET and protect low-voltage systems against voltage faults up to +28V. If the input voltage exceeds the overvoltage threshold, the internal MOSFET is turned off to prevent damage to the protected components. These devices also drive an optional external pFET to protect down to -28V. If the adapter voltage drops below ground, the pFET turns off to prevent damage to the protected components due to negative voltage exposure. The internal charge pump's 15ms (typ) debounce time prevents false turn-on of the internal switch during startup. An open-drain, active-low logic output is available to signal that a successful power-up has occurred. _______________________________________________________________________________________ 5 MAX4943-MAX4946/MAX4944L/MAX4945A/MAX4945L/MAX4949 Pin Description MAX4943-MAX4946/MAX4944L/MAX4945A/MAX4945L/MAX4949 Overvoltage-Protection Controllers with Internal FET OVLO UVLO tOFF IN tOFF tON 80% VIN 10% VIN OUT tINDBC tINDBC tACOK tINDBC tACOK ACOK Figure 2. Timing Diagram Device Operation The MAX4943-MAX4946/MAX4949 have an internal oscillator and charge pump that control the turn-on of the internal switch. The internal oscillator controls the timers that enable the turn-on of the charge pump and controls the state of the open-drain ACOK output. If VIN < VUVLO or if VIN >VOVLO, the internal oscillator remains off, thus disabling the charge pump. If VUVLO < VIN < VOVLO, the internal charge pump is enabled. The charge-pump startup, after a 15ms (typ) internal delay, turns on the internal switch (see Figure 2). ACOK is held high during startup until the ACOK 30ms (typ) blanking period expires. At this point, the device is in its on state. At any time, if VIN drops below VUVLO or rises above V OVLO, ACOK is pulled high and the charge pump is disabled. Internal Switch The MAX4943-MAX4946/MAX4949 incorporate an internal nFET with a 80m (typ) RON. The switch is internally driven by a charge pump that generates a 5V 6 voltage above the input voltage. The internal switch is equipped with 1.2A (min) current-limit protection that turns off the switch within 10s (typ) during an overcurrent fault condition. Autoretry The MAX4943-MAX4946 have an overcurrent autoretry function that turns on the switch again after a 15ms (typ) retry time (see Figure 3). If the faulty load condition is still present after the blanking time, the switch turns off again and the cycle is repeated. The fast turn-off time and 15ms retry time result in a very low duty cycle to keep power consumption low. If the faulty load condition is not present, the switch remains on. Latch The MAX4944B/MAX4945B/MAX4949 do not have the autoretry function, and the switch latches off after an overcurrent fault. The switch remains off until the overcurrent fault has been removed. The switch turns back on when the adapter voltage goes below VUVLO and then returns to the valid operating range. _______________________________________________________________________________________ Overvoltage-Protection Controllers with Internal FET tOFF SWITCH ON SWITCH ON Undervoltage Lockout (UVLO) The MAX4944L/MAX4945L/MAX4946/MAX4949 have a 2.45V (typ) undervoltage-lockout threshold (VUVLO), while the remaining devices have a 4.15V (typ) VUVLO threshold. When VIN is less than VUVLO, ACOK is high impedance. Overvoltage-Lockout Thresholds (OVLO) The MAX4943 has a 7.4V (typ) overvoltage threshold (V OVLO ), the MAX4944_ has a 6.35V (typ) V OVLO threshold, the MAX4945_ has a 5.80V (typ) V OVLO threshold, the MAX4946 has a 4.56V (typ) V OVLO threshold, and the MAX4949 has a 8.90V (typ) VOVLO threshold. When VIN is greater than OVLO, ACOK is high impedance. tRETRY CURRENT THROUGH SWITCH SWITCH OFF ILIM Figure 3. Autoretry Timing Diagram ACOK ACOK is an active-low, open-drain output that asserts low when VUVLO < VIN < VOVLO for the 30ms (typ) period. Connect a pullup resistor from ACOK to the logic I/O voltage of the host system. During a short-circuit fault, ACOK may deassert due to VIN not being in the valid operating voltage range. Thermal-Shutdown Protection The MAX4943-MAX4946/MAX4949 feature thermal-shutdown circuitry. The internal switch turns off when the junction temperature exceeds +175C (typ) and immediately goes into a fault mode. The device exits thermal shutdown after the junction temperature cools by 40C (typ). Applications Information RC 1M CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 100pF RD 1.5k DISCHARGE RESISTANCE DEVICE UNDER TEST STORAGE CAPACITOR Figure 4. Human Body ESD Test Model IN Bypass Capacitor For most applications, bypass IN to GND with a 1F ceramic capacitor as close as possible to the device to enable 15kV (HBM) ESD protection on the pin. If 15kV is not required, there is no capacitor required at IN. If the power source has significant inductance due to long lead length, take care to prevent overshoots due to the LC tank circuit and provide protection if necessary to prevent exceeding the +30V absolute maximum rating on IN. Reverse Polarity Protection The optional external pFET can provide reverse polarity protection down to -28V (for a 30V pFET), if the protect- IP 100% 90% Ir PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE) AMPERES 36.8% 10% 0 0 tRL TIME tDL CURRENT WAVEFORM Figure 5. Human Body Current Waveform _______________________________________________________________________________________ 7 MAX4943-MAX4946/MAX4944L/MAX4945A/MAX4945L/MAX4949 GP GATE Drive When the input voltage goes above ground, GP pulls low and turns on the pFET. An internal clamp protects the pFET by ensuring that the GP to IN voltage does not exceed 19V (max) when the input (IN) rises to +28V. MAX4943-MAX4946/MAX4944L/MAX4945A/MAX4945L/MAX4949 Overvoltage-Protection Controllers with Internal FET ed device does not allow current to flow into OUT. The pFET is turned off when the voltage between GP and IN is less than the pFET gate threshold voltage. RC 50M TO 100M ESD Test Conditions CHARGE-CURRENTLIMIT RESISTOR ESD performance depends on a number of conditions. The MAX4943-MAX4946/MAX4949 are specified for 15kV (HBM) typical ESD resistance on IN when IN is bypassed to ground with a 1F ceramic capacitor. HIGHVOLTAGE DC SOURCE Cs 150pF RD 330 DISCHARGE RESISTANCE STORAGE CAPACITOR DEVICE UNDER TEST Human Body Model Figure 4 shows the Human Body Model and Figure 5 shows the current waveform it generates when discharged into a low impedance. This model consists of a 100pF capacitor charged to the ESD voltage of interest, which is then discharged into the device through a 1.5k resistor. IEC 61000-4-2 The IEC 61000-4-2 standard covers ESD testing and performance of finished equipment. It does not specifically refer to integrated circuits. The MAX4943- MAX4946/MAX4949 are specified for 15kV Air-Gap Discharge and 8kV Contact Discharge IEC 61000-4-2 on the IN pin when IN is bypassed to ground with a 1F ceramic capacitor. The major difference between tests done using the Human Body Model and IEC 61000-4-2 is a higher peak current in IEC 61000-4-2, due to lower series resistance. Figure 6. IEC 61000-4-2 ESD Test Model Hence, the ESD withstand voltage measured to IEC 61000-4-2 generally is lower than that measured using the Human Body Model. Figure 6 shows the IEC 61000-4-2 model. The Contact Discharge method connects the probe to the device before the probe is charged. The Air-Gap Discharge test involves approaching the device with a charged probe. Chip Information PROCESS: BiCMOS Typical Operating Circuit 5V AC ADAPTER 1F GP IN VI/0 TO C OUT 15ms (typ) DEBOUNCE ACOK 30ms (typ) TIMER GND 8 CHARGE PUMP CHARGER DC-DC CONVERTER MAX4943-MAX4946/MAX4944L/ MAX4945L/MAX4949 _______________________________________________________________________________________ Overvoltage-Protection Controllers with Internal FET PACKAGE TYPE PACKAGE CODE DOCUMENT NO. 8 DFN L822-1 21-0164 _______________________________________________________________________________________ 9 MAX4943-MAX4946/MAX4944L/MAX4945A/MAX4945L/MAX4949 Package Information For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. MAX4943-MAX4946/MAX4944L/MAX4945A/MAX4945L/MAX4949 Overvoltage-Protection Controllers with Internal FET Revision History REVISION NUMBER REVISION DATE 2 7/07 -- 3 6/08 Added MAX4945A to the Ordering Information/Selector Guide and Electrical Characterstics tables DESCRIPTION PAGES CHANGED 1, 2, 3 1, 2 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. 10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc. Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Maxim Integrated: MAX4944BELA+T MAX4944ELA+T MAX4944LELA+T MAX4945AELA+T MAX4945BELA+T MAX4945ELA+T MAX4945LELA+T MAX4946ELA+T MAX4949ELA+T