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| 19-4357; Rev 0; 10/08 Adjustable Overvoltage Protector with High Accuracy General Description The MAX14527/MAX14528 overvoltage protection devices feature a low 100m (typ) RON internal FET and protect low-voltage systems against voltage faults up to +28V. When the input voltage exceeds the overvoltage threshold, the internal FET is turned off to prevent damage to the protected components. The overvoltage protection threshold can be adjusted with optional external resistors to any voltage between 4V and 8V. With the OVLO input set below the external OVLO select voltage, the MAX14527/MAX14528 automatically choose the internal 2.5% accurate trip thresholds. The internal overvoltage thresholds (OVLO) are preset to 5.75V typical (MAX14527) or 6.76V typical (MAX14528). The MAX14527/MAX14528 are also protected against overcurrent events with an internal thermal shutdown. The MAX14527/MAX14528 are offered in a small, 8-pin TDFN-EP package and operate over the -40C to +85C extended temperature range. Input Voltage Protection Up to +28V Preset Internal 2.5% Accurate OVLO Thresholds 5.75V (MAX14527) 6.76V (MAX14528) Adjustable Overvoltage Protection Trip Level Integrated 100m (typ) n-Channel MOSFET Switch Soft-Start to Minimize In-Rush Current Automatic Overvoltage Protection Trip-Level Selection Internal 15ms Startup Delay Thermal Shutdown Protection 8-Pin TDFN (2mm x 2mm) Package -40C to +85C Operating Temperature Range Features MAX14527/MAX14528 Applications Cell Phones Media Players PDAs and Palmtop Devices PART MAX14527ETA+T MAX14528ETA+T Ordering Information PIN-PACKAGE 8 TDFN-EP* 8 TDFN-EP* TOP MARK ACR ACS OVLO (V) 5.75 6.76 Pin Configuration appears at end of data sheet. Note: Devices are specified over the -40C to +85C temperature range. +Denotes a lead-free/RoHS-compliant package. T = Tape and reel. *EP = Exposed pad. Typical Application Circuit VBUS USB CONNECTOR 1F IN IN OUT OUT CHARGER INPUT PMIC R1 OVLO * MAX14527 MAX14528 GND R2 *R1 AND R2 ARE REQUIRED ONLY FOR ADJUSTABLE OVLO; OTHERWISE, CONNECT OVLO TO GND. ________________________________________________________________ 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. Adjustable Overvoltage Protector with High Accuracy MAX14527/MAX14528 ABSOLUTE MAXIMUM RATINGS (All voltages referenced to GND.) IN ............................................................................-0.3V to +30V OUT .............................................................-0.3V to (VIN + 0.3V) OVLO........................................................................-0.3V to +6V Continuous IN Current .............................................................1A Peak IN Current (Note 1)..........................................................5A Continuous OVLO Current ...................................................50A Continuous Power Dissipation (TA = +70C) 8-Pin TDFN (derate 11.9mW/C above +70C) ...........954mW Package Junction-to-Ambient Thermal Resistance (JA) (Note 2) .....................................................................83.9C/W Package Junction-to-Case Thermal Resistance (JC) (Note 2) ........................................................................37C/W Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering) .........................................+300C Note 1: Limited by thermal shutdown. Note 2: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial. 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 = +2.2V to +28V, TA = -40C to +85C, unless otherwise noted. Typical values are at VIN = +5.0V and TA = +25C.) (Note 3) PARAMETER Input Voltage Range Input Supply Current SYMBOL VIN IIN VIN < OVLO VIN rising IN Overvoltage Trip Level VIN_OVLO VIN falling IN Overvoltage Lockout Hysteresis OVLO Set Threshold Adjustable OVLO Threshold Range External OVLO Select Threshold Switch On-Resistance OVLO Clamp OUT Capacitor OVLO Input Leakage Current Thermal Shutdown Thermal Shutdown Hysteresis TIMING CHARACTERISTICS (Figure 1) Debounce Time tINDBC Time from 2.2V < VIN < VIN_OVLO to VOUT = 10% of VIN 2.2V < VIN < VIN_OVLO, RLOAD = 100, CLOAD = 100F; VOUT from 10% to 90% of VIN 2.2V < VIN < VIN_OVLO, RLOAD = 100, CLOAD = 1mF; VOUT from 10% to 90% of VIN VIN > VOVLO_THRESH to VOUT = 80% of VIN_OVLO; RLOAD = 1k, VIN rising at 2V/100ns 15 ms COUT IOVLO VIN_OVLO_HYS VOVLO_THRESH VOVLO_SELECT RON ICLAMP = 10A VOVLO_THRESH = 1.245V 3 -100 150 20 1.2 4 0.15 MAX14527 MAX14528 MAX14527 MAX14528 5.6 6.55 5.54 6.5 1 1.245 0.33 100 4.56 1.29 8 0.5 200 5.5 1000 +100 CONDITIONS MIN 2.2 80 5.75 6.765 TYP MAX 28 160 5.9 7 5.84 6.95 V UNITS V A % V V V m V F nA C C 0.7 ms 1.4 Switch Turn-On Time tON Switch Turn-Off Time tOFF 1.3 3.5 s Note 3: All specifications are 100% production tested at TA = +25C, unless otherwise noted. Specifications are over -40C to +85C and are guaranteed by design. 2 _______________________________________________________________________________________ Adjustable Overvoltage Protector with High Accuracy Timing Diagram MAX14527/MAX14528 OVLO 2.2V IN tON 90% OUT 10% tON 80% VIN_OVLO 90% 10% VIN_OVLO tOFF tINDBC NOTE: WAVEFORMS ARE NOT TO SCALE. tINDBC Figure 1. Timing Characteristics _______________________________________________________________________________________ 3 Adjustable Overvoltage Protector with High Accuracy MAX14527/MAX14528 Typical Operating Characteristics (TA = +25C, unless otherwise noted.) IN SUPPLY CURRENT vs. IN VOLTAGE MAX14527/8 toc01 NORMALIZED R0N vs. TEMPERATURE MAX14527/8 toc02 NORMALIZED OVLO THRESHOLD vs. TEMPERATURE 1.04 NORMALIZED OVLO THRESHOLD 1.03 1.02 1.01 1.00 0.99 0.98 0.97 0.96 0.95 MAX14527/8 toc03 90 80 IN SUPPLY CURRENT (A) 70 60 50 40 30 20 10 0 0 7 14 IN VOLTAGE (V) 21 TA = -40C TA = +25C TA = +85C 1.5 1.4 1.3 NORMALIZED RON 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 VIN = 5.0V VIN = 3.6V 1.05 28 -40 -15 10 35 60 85 -40 -15 10 35 60 85 TEMPERATURE (C) TEMPERATURE (C) NORMALIZED EXTERNAL OVLO SET THRESHOLD vs. TEMPERATURE NORMALIZED EXTERNAL OVLO SELECT THRESHOLD MAX14527/8 toc04 NORMALIZED EXTERNAL OVLO SELECT THRESHOLD vs. TEMPERATURE MAX14527/8 toc05 NORMALIZED DEBOUNCE TIME vs. TEMPERATURE 1.04 NORMALIZED DEBOUNCE TIME 1.03 1.02 1.01 1.00 0.99 0.98 0.97 0.96 0.95 MAX14527/8 toc06 NORMALIZED EXTERNAL OVLO SET THRESHOLD 1.05 1.04 1.03 1.02 1.01 1.00 0.99 0.98 0.97 0.96 0.95 -40 -15 10 35 60 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 -40 -15 10 35 60 1.05 85 85 -40 -15 10 35 60 85 TEMPERATURE (C) TEMPERATURE (C) TEMPERATURE (C) POWER-UP RESPONSE MAX14527/8 toc07 OVERVOLTAGE FAULT RESPONSE MAX14527/8 toc08 VIN 5V/div VOUT 5V/div VIN 5V/div VOUT 5V/div IOUT 100mA/div IOUT 50mA/div 10ms/div 1s/div 4 _______________________________________________________________________________________ Adjustable Overvoltage Protector with High Accuracy Pin Description PIN 1, 2 NAME IN FUNCTION Voltage Input. Bypass IN with a 1F ceramic capacitor as close as possible to the device to obtain 15kV Human Body Model (HBM) ESD protection. Connect all the IN pins together for proper operation. IN is protected to 2kV HBM when IN is not bypassed with a capacitor to GND. External OVLO Adjustment. Connect OVLO to GND when using the internal threshold. Connect a resistordivider to OVLO to set a different OVLO threshold; this external resistor-divider is completely independent from the internal threshold. Internally Connected. Do not connect. Leave I.C. unconnected. Ground Output Voltage. Output of internal switch. Connect all the OUT outputs together for proper operation. Exposed Pad. Connect exposed pad to ground. For enhanced thermal dissipation, connect EP to a copper area as large as possible. Do not use EP as a sole ground connection. MAX14527/MAX14528 3 4, 5 6 7, 8 -- OVLO I.C. GND OUT EP Functional Diagram IN IN CHARGE PUMP OUT OUT TEMPERATURE FAULTS VBG REFERENCE + OVLO SEL GND LOGIC CONTROL MAX14527 MAX14528 Detailed Description The MAX14527/MAX14528 overvoltage protection devices feature a low RON internal FET and protect lowvoltage systems against voltage faults up to +28V. If the input voltage exceeds the overvoltage threshold, the internal FET is turned off to prevent damage to the protected components. The 15ms debounce time prevents false turn-on of the internal FET during startup. Device Operation The MAX14527/MAX14528 have timing logic that controls the turn-on of the internal FET. If V IN < VOVLO_THRESH, the internal charge pump is enabled. The charge-pump startup, after a 15ms debounce delay, turns on the internal FET (see the Functional Diagram). At any time, if V IN rises above V OVLO_ THRESH, OUT is disconnected from IN. _______________________________________________________________________________________ 5 Adjustable Overvoltage Protector with High Accuracy MAX14527/MAX14528 Internal Switch The MAX14527/MAX14528 incorporate an internal FET with a 100m (typ) RON. The FET is internally driven by a charge pump that generates a necessary gate voltage above IN. The internal FET is capable of passing more than 5A inrush current. ESD Test Conditions ESD performance depends on a number of conditions. The MAX14527/MAX14528 are specified for 15kV (HBM) typical ESD resistance on IN when IN is bypassed to ground with a 1F ceramic capacitor. HBM ESD Protection Figure 2a shows the Human Body Model, and Figure 2b 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. Overvoltage Lockout (OVLO) The MAX14527 has a 5.75V (typ) overvoltage threshold (OVLO).The MAX14528 has a 6.76V (typ) OVLO threshold. Thermal-Shutdown Protection The MAX14527/MAX14528 feature thermal shutdown circuitry. The internal FET turns off when the junction temperature exceeds +150C (typ). The device exits thermal shutdown after the junction temperature cools by 20C (typ). RC 1M CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE RD 1.5k DISCHARGE RESISTANCE DEVICE UNDER TEST Applications Information 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 IN. If 15kV (HBM) ESD 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. Cs 100pF STORAGE CAPACITOR Figure 2a. Human Body ESD Test Model OUT Output Capacitor The slow turn-on time provides a soft-start function that allows the MAX14527/MAX14528 to charge an output capacitor up to 1000F. IP 100% 90% AMPERES IR PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE) External OVLO Adjustment Functionality If OVLO is connected to ground, the internal OVLO comparator uses the internally set OVLO value. If an external resistor-divider is connected to OVLO and V OVLO exceeds the OVLO select voltage, VOVLO_ SELECT, the internal OVLO comparator reads the IN fraction fixed by the external resistor divider. R1 = 1M is a good starting value for minimum current consumption. Since VIN_OVLO, VOVLO_THRESH, and R1 are known, R2 can be calculated from the following formula: R VIN_OVLO = VOVLO_THRESH x 1 + 1 R2 This external resistor-divider is completely independent from the internal resistor-divider. 36.8% 10% 0 0 tRL TIME tDL CURRENT WAVEFORM Figure 2b. Human Body Current Waveform 6 _______________________________________________________________________________________ Adjustable Overvoltage Protector with High Accuracy Pin Configuration PROCESS: BiCMOS TOP VIEW Chip Information MAX14527/MAX14528 IN IN OVLO I.C. 1 2 3 4 8 7 OUT OUT GND I.C. MAX14527 MAX14528 *EP 6 5 TDFN 2mm x 2mm *CONNECT EXPOSED PAD TO GND. Package Information For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. PACKAGE TYPE 8 TDFN-EP PACKAGE CODE T822+2 DOCUMENT NO. 21-0168 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 _____________________ 7 (c) 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc. |
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