19-3044; Rev 1; 4/04 Overvoltage Protection Controllers with Status FLAG On power-up, the device waits for 50ms before driving GATE high. FLAG is held low for an additional 50ms after GATE goes high before deasserting. The MAX4838/MAX4840/MAX4842 have an open-drain FLAG output, and the MAX4839/MAX4841 have a pushpull FLAG output. The FLAG output asserts immediately to an overvoltage fault. Additional features include a 15kV ESD-protected input (when bypassed with a 1µF capacitor) and a shutdown pin (EN) to turn off the device (MAX4838/MAX4840/ MAX4842). All devices are offered in a small 6-pin SC70 package and are specified for operation from -40°C to +85°C. Features ♦ Overvoltage Protection Up to 28V ♦ Preset 7.4V, 5.8V, or 4.7V Overvoltage Trip Level ♦ Drive Low-Cost NMOS FET ♦ Internal 50ms Startup Delay ♦ Internal Charge Pump ♦ Undervoltage Lockout ♦ 15kV ESD-Protected Input ♦ Voltage Fault FLAG Indicator ♦ 6-Pin SC70 Package Ordering Information PART TEMP RANGE PINPACKAGE TOP MARK MAX4838EXT-T -40°C to +85°C 6 SC70-6 ABW MAX4839EXT-T -40°C to +85°C 6 SC70-6 ABY MAX4840EXT-T -40°C to +85°C 6 SC70-6 ABX MAX4841EXT-T -40°C to +85°C 6 SC70-6 ABZ MAX4842EXT-T -40°C to +85°C 6 SC70-6 ACE Typical Operating Circuit Applications Cell Phones INPUT +1.2V TO +28V Digital Still Cameras OUTPUT PDAs and Palmtop Devices NMOS MP3 Players 1 Selector Guide PART MAX4838EXT-T OV UVLO TRIP EN THRESHOLD LEVEL INPUT (V) (V) 3.25 7.4 Yes FLAG OUTPUT MAX4839EXT-T 3.25 7.4 No Push-Pull MAX4840EXT-T 3.25 5.8 Yes Open-Drain MAX4841EXT-T 3.25 5.8 No Push-Pull MAX4842EXT-T 3.00 4.7 Yes Open-Drain GATE 4 VIO 1µF MAX4838– MAX4842 6 2 Open-Drain IN EN GND FLAG 3 NOTE: EN AND PULLUP RESISTOR ON MAX4838/ MAX4840/MAX4842 ONLY. Pin Configuration appears at end of data sheet. ________________________________________________________________ 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 MAX4838–MAX4842 General Description The MAX4838–MAX4842 are overvoltage protection ICs that protect low-voltage systems against voltages of up to 28V. If the input voltage exceeds the overvoltage trip level, the MAX4838–MAX4842 turn off the low-cost external n-channel FET(s) to prevent damage to the protected components. An internal charge pump eliminates the need for external capacitors and drives the FET gate for a simple, robust solution. The MAX4838/MAX4839 have a 7.4V overvoltage threshold, and the MAX4840/MAX4841 have a 5.8V overvoltage threshold. The MAX4842 has a 4.7V overvoltage threshold. The MAX4838–MAX4841 have an undervoltage lockout (UVLO) threshold of 3.25V while the MAX4842 has a UVLO of 3.0V. In addition to the single FET configuration, the devices can be configured with back-to-back external FETs to prevent currents from being back-driven into the adapter. MAX4838–MAX4842 Overvoltage Protection Controllers with Status FLAG ABSOLUTE MAXIMUM RATINGS IN to GND ..............................................................-0.3V to +30V GATE to GND ........................................................-0.3V to +12V EN, FLAG to GND ....................................................-0.3V to +6V Continuous Power Dissipation (TA = +70°C) 6-Pin SC70 (derate 3.1mW/°C above +70°C) .............245mW 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 = +5V (MAX4838–MAX4841), VIN = +4V (MAX4842), TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER Input Voltage Range Undervoltage Lockout Threshold SYMBOL CONDITIONS VIN UVLO MIN 1.2 OVLO IIN GATE Pulldown Current 28.0 V 3.0 3.25 3.5 MAX4842 2.8 3.0 3.2 MAX4838/MAX4839 7.0 7.4 7.8 MAX4840/MAX4841 MAX4842 5.5 4.4 5.8 4.7 6.1 5.0 VIN falling VGATE 100 80 50 No load, EN = GND or 5.5V, VIN = 5.4V (MAX4838–MAX4841) 140 240 No load, EN = GND or 4.4V, VIN = 4.3V (MAX4842) 130 220 IPD IGATE sourcing 1µA MAX4838–MAX4841 MAX4842 V mV MAX4838/MAX4839 MAX4840/MAX4841 MAX4842 V mV µA VIN = 2.9V (MAX4838–MAX4841), VIN = 2.7V (MAX4842) UVLO Supply Current GATE Voltage UNITS 50 Overvoltage Trip Level Hysteresis IN Supply Current MAX MAX4838–MAX4841 Undervoltage Lockout Hysteresis Overvoltage Trip Level TYP 150 9 10 7.5 8.0 VIN > VOVLO, VGATE = 5.5V 60 µA V mA 1.2V ≤ VIN < UVLO, ISINK = 50µA 0.4 VIN ≥ OVLO, ISINK = 1mA 0.4 FLAG Output Low Voltage VOL FLAG Output High Voltage VOH ISOURCE = 100µA, FLAG deasserted, MAX4839/MAX4841 FLAG Output High Leakage IOH VFLAG = 5.5V, FLAG deasserted, MAX4838/MAX4840/MAX4842 EN Input High Voltage VIH MAX4838/MAX4840/MAX4842 EN Input Low Voltage VIL MAX4838/MAX4840/MAX4842 0.65 V ILKG MAX4838/MAX4840/MAX4842, EN = GND or 5.5V 1 µA EN Input Leakage IN ESD rating 2 CIN ≥ 1µF 2.4 V V 1 1.47 µA V Human Body Model 15 IEC 1000-4-2 15 _______________________________________________________________________________________ kV Overvoltage Protection Controllers with Status FLAG (VIN = +5V (MAX4838–MAX4841), VIN = +4V (MAX4842), TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS TIMING Startup Delay tSTART VIN > VUVLO, VGATE > 0.3V, Figure 1 20 50 80 ms FLAG Blanking Time tBLANK VGATE = 0.3V, VFLAG = 2.4V, Figure 1 20 50 80 ms GATE Turn-On Time tGON VGATE = 0.3V to 8V (MAX4838–MAX4841), VGATE = 0.3V to 6V (MAX4842), CGATE = 1500pF, Figure 1 10 tGOFF VIN increasing from 5V to 8V at 3V/µs (MAX4838–MAX4841), VIN increasing from 4V to 6V at 2V/µs (MAX4842), VGATE = 0.3V, CGATE = 1500pF, Figure 2 6 tFLAG VIN increasing from 5V to 8V at 3V/µs (MAX4838–MAX4841), VIN increasing from 4V to 6V at 2V/µs (MAX4842), VFLAG = 0.4V, Figure 2 5.8 µs Initial Overvoltage Fault Delay tOVP VIN increasing from 0 to 8V (MAX4838–MAX4841), VIN increasing from 0V to 6V (MAX4842), IGATE = 80% of IPD, Figure 3 100 ns Disable Time tDIS VEN = 2.4V, VGATE = 0.3V, MAX4838/MAX4840/MAX4842, Figure 4 580 ns GATE Turn-Off Time FLAG Assertion Delay ms 20 µs Note 1: All parts are 100% tested at +25°C. Electrical limits across the full temperature range are guaranteed by design and correlation. Typical Operating Characteristics (VIN = +5V, MAX4838; Si9936DY external MOSFET in back-to-back configuration; TA = +25°C, unless otherwise noted.) REVERSE CURRENT vs. OUTPUT VOLTAGE 300 200 100 9 GATE VOLTAGE (V) 400 12 MAX4838 toc02 SINGLE MOSFET REVERSE CURRENT (µA) 500 SUPPLY CURRENT (µA) 1000 MAX4838 toc01 600 MAX4838–MAX4841 GATE VOLTAGE vs. INPUT VOLTAGE MAX4838 toc03 SUPPLY CURRENT vs. INPUT VOLTAGE 10 1 6 MAX4840 MAX4841 MAX4838 MAX4839 3 BACK-TO-BACK MOSFETS 100 0.1 0 0 5 10 15 20 INPUT VOLTAGE (V) 25 30 0 3.5 4.0 4.5 5.0 OUTPUT VOLTAGE (V) 5.5 3 4 5 6 7 8 INPUT VOLTAGE (V) _______________________________________________________________________________________ 3 MAX4838–MAX4842 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (continued) (VIN = +5V, MAX4838; Si9936DY external MOSFET in back-to-back configuration; TA = +25°C, unless otherwise noted.) MAX4842 GATE VOLTAGE vs. INPUT VOLTAGE MAX4838–MAX4841 POWER-UP RESPONSE GATE VOLTAGE vs. INPUT VOLTAGE MAX4838 toc06 MAX4838 toc05 11.0 MAX4838 toc04 12 IGATE = 0 9 GATE VOLTAGE (V) 10.5 MAX4842 GATE VOLTAGE (V) MAX4838–MAX4842 Overvoltage Protection Controllers with Status FLAG 6 3 5V 0V IGATE = 4µA 10V IGATE = 8µA 10.0 OUT 5V 0V 5V ROUT = ∞ COUT = 0 FLAG 9.0 0 1 2 3 4 5 6 7 8 5.0 INPUT VOLTAGE (V) 5.1 5.2 5.3 5.4 5.5 20ms/div INPUT VOLTAGE (V) MAX4838–MAX4841 POWER-UP RESPONSE MAX4842 POWER-UP RESPONSE MAX4838 toc07 MAX4842 POWER-UP RESPONSE MAX4838 toc08 5V IN 0V 4V MAX4838 toc09 IN 0V 8V 10V IIN 0A GATE 0V 4V OUT 0V 4V 0V ROUT = 5Ω IN GATE 0V 1A 4V 0V 8V GATE 0V 5V GATE 0V 9.5 0 IN ROUT = ∞ COUT = 0 FLAG FLAG 800mA IIN 0A 4V 0V ROUT = 5Ω FLAG 0V 20ms/div 20ms/div POWER-UP OVERVOLTAGE RESPONSE OVERVOLTAGE RESPONSE IN 5V 8V GATE MAX4838 toc12 IN GATE PULLED UP TO IN WITH 100Ω 0V 10V 0V POWER-DOWN RESPONSE MAX4838 toc11 MAX4838 toc10 8V 20ms/div 5V 10V GATE IGATE IGATE 0V FLAG 400ns/div 4 0A 5V OUT 0V 5V CGATE = 1500pF GATE 0V 50mA 0A 5V IN 0V 0V 40mA 5V RLOAD = 50Ω RFLAG = 100kΩ TO +5V FLAG 0V 5V FLAG 0V 1µs/div _______________________________________________________________________________________ 10ms/div Overvoltage Protection Controllers with Status FLAG PIN MAX4838/ MAX4840/ MAX4842 MAX4839/ MAX4841 NAME 1 1 IN 2 2 GND Ground FUNCTION Input. IN is both the power-supply input and the overvoltage sense input. Bypass IN to GND with a 1µF capacitor or larger. 3 3 FLAG Fault Indication Output, Active Low. FLAG is asserted low during undervoltage lockout and overvoltage lockout conditions. FLAG is deasserted during normal operation. FLAG is open-drain on the MAX4838/MAX4840/MAX4842, and push-pull on the MAX4839/MAX4841. 4 4 GATE Gate-Drive Output. GATE is the output of an on-chip charge pump. When VUVLO < VIN < VOVLO, GATE is driven high to turn on the external N-channel MOSFET(s). 5 5, 6 N.C. 6 — EN No Connection. Can be connected to GND. Device Enable Input, Active Low. Drive EN low or connect to ground to allow normal device operation. Drive EN high to turn off the external MOSFET. Timing Diagrams VIN 5V (4V) VOVLO 5V (4V) tGON 0V 8V (6V) VIN VUVLO tFLAG tGOFF 8V (6V) tSTART VGATE VGATE 0.3V 0.3V tBLANK 2.4V VFLAG VFLAG 0.4V ( ) MAX4842 ( ) MAX4842 Figure 2. Shutdown Timing Diagram Figure 1. Startup Timing Diagram VIN 8V (6V) VEN VOVLO 1.47V 0V tOVP tDIS 80% IGATE VGATE 0.3V ( ) MAX4842 Figure 3. Power-Up Overvoltage Timing Diagram Figure 4. Disable Timing Diagram _______________________________________________________________________________________ 5 MAX4838–MAX4842 Pin Description MAX4838–MAX4842 Overvoltage Protection Controllers with Status FLAG IN 5.5V REGULATOR 2x CHARGE PUMP GATE DRIVER GATE GND UVLO AND OVLO DETECTOR EN CONTROL LOGIC AND TIMER FLAG MAX4838– MAX4842 Figure 5. Functional Diagram Detailed Description The MAX4838–MAX4842 provide up to 28V overvoltage protection for low-voltage systems. When the input voltage exceeds the overvoltage trip level, the MAX4838– MAX4842 turn off a low-cost external n-channel FET(s) to prevent damage to the protected components. An internal charge pump (Figure 5) drives the FET gate for a simple, robust solution. Undervoltage Lockout (UVLO) The MAX4838–MAX4841 have a fixed 3.25V typical undervoltage lockout level (UVLO) while the MAX4842 has a 3.0V typical UVLO. When VIN is less than the UVLO, the GATE driver is held low and FLAG is asserted. Overvoltage Lockout (OVLO) The MAX4838/MAX4839 have a 7.4V typical overvoltage threshold (OVLO), and the MAX4840/MAX4841 have a 5.8V typical overvoltage threshold. The MAX4842 has a 4.7V typical overvoltage threshold. When VIN is greater than OVLO, the GATE driver is held low and FLAG is asserted. FLAG Output The FLAG output is used to signal the host system there is a fault with the input voltage. FLAG asserts immediately to an overvoltage fault. FLAG is held low for 50ms after GATE turns on before deasserting. The MAX4839 and MAX4841 have a push-pull FLAG output. The output high voltage is proportional to VIN for VIN up to 5.5V, and fixed at 5.5V when VIN > 5.5V. The MAX4838/MAX4840/MAX4842 have an open-drain FLAG output. Connect a pullup resistor from FLAG to the logic I/O voltage of the host system. 6 EN Enable Input EN is an active-low enable input on the MAX4838/ MAX4840/MAX4842 only. Drive EN low or connect to ground to enable normal device operation. Drive EN high to force the external MOSFET(s) off. EN does not override an OVLO or UVLO fault. GATE Driver An on-chip charge pump is used to drive GATE above IN, allowing the use of low-cost n-channel MOSFETS. The charge pump operates from the internal 5.5V regulator. The actual GATE output voltage tracks approximately two times VIN until VIN exceeds 5.5V or the OVLO trip level is exceeded, whichever comes first. The MAX4838/MAX4839 have a 7.4V typical OVLO, therefore GATE remains relatively constant at about 10.5V for 5.5V < VIN < 7.4V. The MAX4840/MAX4841 have a 5.8V typical OVLO, but this can be as low as 5.5V. The MAX4840/MAX4841 in practice may never actually achieve the full 10.5V GATE output. The MAX4842 has a 4.7V (typ) OVLO and the GATE output voltage is 2x the input voltage. The GATE output voltage as a function of input voltage is shown in the Typical Operating Characteristics. Device Operation The MAX4838–MAX4842 have an on-board state machine to control device operation. A flowchart is shown in Figure 6. On initial power-up, if VIN < UVLO or if VIN > OVLO, GATE is held at 0V, and FLAG is low. If UVLO < VIN < OVLO and EN is low, the device enters startup after a 50ms internal delay. The internal charge pump is enabled, and GATE begins to be driven above VIN by the internal charge pump. FLAG is held low during startup until the FLAG blanking period expires, typi- _______________________________________________________________________________________ Overvoltage Protection Controllers with Status FLAG VIN > UVLO 1 IN GATE 4 VIO 1µF TIMER STARTS COUNTING VIN < UVLO OUTPUT NMOS INPUT 0 TO 28V MAX4838– MAX4842 6 t = 50ms 2 OVLO CHECK GATE = 0 FLAG = LOW EN FLAG GND 3 NOTE: EN AND PULLUP RESISTOR ON MAX4838/ MAX4840/MAX4842 ONLY. VIN < OVLO STARTUP GATE DRIVEN HIGH FLAG = LOW VIN > OVLO t = 50ms Figure 7. Back-to-Back External MOSFET Configuration MOSFET. If this is a concern, then the back-to-back configuration should be used. MOSFET Selection ON GATE HIGH FLAG = HIGH Figure 6. State Diagram cally 50ms after the GATE starts going high. At this point the device is in its on state. At any time if VIN drops below UVLO, FLAG is driven low and GATE is driven to ground. Applications Information MOSFET Configuration The MAX4838–MAX4842 can be used with either a single MOSFET configuration as shown in the Typical Operating Circuit, or can be configured with a back-toback MOSFET as shown in Figure 7. The MAX4838–MAX4842 can drive either a single MOSFET or back-to-back MOSFETs. The back-to-back configuration has almost zero reverse current when the input supply is below the output. If reverse current leakage is not a concern, a single MOSFET can be used. This approach has half the loss of the back-to-back configuration when used with similar MOSFET types, and is a lower cost solution. Note that if the input is actually pulled low, the output is pulled low as well due to the parasitic body diode in the The MAX4838–MAX4842 are designed for use with either a single n-channel MOSFET or dual back-to-back n-channel MOSFETs. In most situations, MOSFETs with RDS(ON) specified for a VGS of 4.5V work well. If the input supply is near the UVLO maximum of 3.5V consider using a MOSFET specified for a lower VGS voltage. Also the VDS should be 30V for the MOSFET to withstand the full 28V IN range of the MAX4838– MAX4842. Table 1 shows a selection of MOSFETs appropriate for use with the MAX4838–MAX4842. IN Bypass Considerations For most applications, bypass IN to GND with a 1µF ceramic capacitor. 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. The MAX4838–MAX4842 provide protection against voltage faults up to 28V, but this does not include negative voltages. If negative voltages are a concern, connect a Schottky diode from IN to GND to clamp negative input voltages. ESD Test Conditions ESD performance depends on a number of conditions. The MAX4838–MAX4842 are specified for 15kV typical ESD resistance on IN when IN is bypassed to ground with a 1µF ceramic capacitor. Contact Maxim for a reli- _______________________________________________________________________________________ 7 MAX4838–MAX4842 STANDBY GATE = 0 FLAG = LOW MAX4838–MAX4842 Overvoltage Protection Controllers with Status FLAG Table 1. MOSFET Suggestions CONFIGURATION/ PACKAGE VDS MAX (V) RON AT 4.5V (mΩ) Si5902DC Dual/1206-8 30 143 Si1426DH Single/SC70-6 30 115 PART FDC6305N Dual/SSOT-6 20 80 FDC6561AN Dual/ SSOT-6 30 145 FDG315N Single/SC70-6 30 160 ability report that documents test setup, methodology, and results. Human Body Model Figure 8 shows the Human Body Model and Figure 9 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 1.5kΩ resistor. IEC 1000-4-2 Since January 1996, all equipment manufactured and/or sold in the European community has been required to meet the stringent IEC 1000-4-2 specification. The IEC 1000-4-2 standard covers ESD testing and performance of finished equipment; it does not specifically refer to RC 1MΩ CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 100pF Vishay Silconix www.vishay.com 402-563-6866 Fairchild Semiconductor www.fairchildsemi.com 207-775-8100 integrated circuits. The MAX4838–MAX4842 help users design equipment that meets Level 3 of IEC 1000-4-2, without additional ESD-protection components. The main difference between tests done using the Human Body Model and IEC 1000-4-2 is higher peak current in IEC 1000-4-2. Because series resistance is lower in the IEC 1000-4-2 ESD test model (Figure 10), the ESD-withstand voltage measured to this standard is generally lower than that measured using the Human Body Model. Figure 11 shows the current waveform for the ±8kV IEC 1000-4-2 Level 4 ESD Contact Discharge test. The Air-Gap test involves approaching the device with a charger probe. The Contact Discharge method connects the probe to the device before the probe is energized. RD 1.5kΩ IP 100% 90% DISCHARGE RESISTANCE STORAGE CAPACITOR DEVICE UNDER TEST Ir Figure 8. Human Body ESD Test Model PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE) AMPERES 36.8% 10% 0 0 8 MANUFACTURER tRL TIME tDL CURRENT WAVEFORM Figure 9. Human Body Model Current Waveform _______________________________________________________________________________________ Overvoltage Protection Controllers with Status FLAG MAX4838–MAX4842 I 100% CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 150pF RD 330Ω 90% DISCHARGE RESISTANCE I PEAK RC 50Ω to 100Ω DEVICE UNDER TEST STORAGE CAPACITOR 10% t r = 0.7ns to 1ns t 30ns 60ns Figure 10. IEC 1000-4-2 ESD Test Model Figure 11. IEC 1000-4-2 ESD Generator Current Chip Information Pin Configuration TRANSISTOR COUNT: 737 PROCESS: BiCMOS TOP VIEW IN 1 GND 2 MAX4838– MAX4842 FLAG 3 6 EN (N.C.) 5 N.C. 4 GATE ( ) FOR MAX4839 AND MAX4841 ONLY. _______________________________________________________________________________________ 9 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.) SC70, 6L.EPS MAX4838–MAX4842 Overvoltage Protection Controllers with Status FLAG 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 © 2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.