19-1791; Rev 0; 10/00 Micropower Adjustable Overvoltage Protection Controllers Features ♦ Five 3% Accurate Overvoltage Comparators ♦ Series PFET Gate Driver with VGS Limiter ♦ 21µA Quiescent Supply Current ♦ 4µA Shutdown Current ♦ 4.4V to 28V Operating Voltage Range ♦ 3% Accurate Comparator with 10% Hysteresis for Low-Battery Detection (MAX1808) ♦ 28V Open-Drain N-Channel Output (MAX1807) ♦ Small 10-Pin µMAX Package Ordering Information ________________________Applications Notebook Computers PART Power-Supply Modules Multi-Output Power Supplies TEMP. RANGE PIN-PACKAGE MAX1807EUB -40°C to +85°C 10 µMAX MAX1808EUB -40°C to +85°C 10 µMAX Pin Configuration and Typical Operating Circuit appear at end of data sheet. Functional Diagram VDD ON 1V REF + TH (MAX1808) 2.5V INTERNAL SUPPLY REF OK POWER-ON RESET (60µs) PMOS POWER DRIVER DP _ IN1 + _- IN2 + _ IN3 + _ IN4 + _ IN5 + _ R S Q FAULT (MAX1807) MAX1807 MAX1808 GND ________________________________________________________________ Maxim Integrated Products 1 For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX1807/MAX1808 General Description The MAX1807/MAX1808 monitor up to five supply rails for an overvoltage condition and provide a latched output when any one of the five supplies exceeds the trip thresholds. The latched output drives an external Pchannel load switch to remove power when an overvoltage condition is detected. The latch is reset when a logic low is input to ON or the power supply is cycled. The MAX1807 provides a 28V open-drain fault output that can be used to trigger an alert, trip a resetable fuse, or for other purposes. The MAX1808 includes a low-battery comparator with hysteresis to drive the DP output high, turning off the external P-channel switch when the input voltage is too low. The MAX1807/MAX1808 are available in a miniature 10pin µMAX package. MAX1807/MAX1808 Micropower Adjustable Overvoltage Protection Controllers ABSOLUTE MAXIMUM RATINGS IN1_, TH to GND.......................................................-0.3V to +6V ON, VDD, FAULT to GND........................................-0.3V to +30V DP to GND..................................................-0.3V to (VDD + 0.3V) Continuous Power Dissipation 10-Pin µMAX (derate 5.6mW/°C above +70°C)...........448mW 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 (VDD = VON = 15V, VIN1–VIN5 = 0.5V, VTH = 2.0V, CDP = 5nF, FAULT = open, TA = 0°C to +85°C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 2 28 V 4.4 28 V 4.0 V GENERAL VDD Input Voltage Range DP and FAULT in correct state (Table 1) VDD Operating Voltage Range VDD Undervoltage Lockout Threshold Rising trip level, typical 2% hysteresis; when VDD is below this level, DP = Hi and FAULT = Hi-Z 2 2.7 Supply Current VTH = 2V or 0.5V 21 45 µA Shutdown Current VDD = 15V, VON = GND, VIN1–VIN5 = VTH = GND 4 8.5 µA 1 1.03 V COMPARATORS (IN1–IN5, TH) IN1–IN5 Input Trip Level Rising edge, typical 1% hysteresis, VDD = 4.4V to 28V TH Input Trip Level, Falling VDD = 4.4V to 28V (MAX1808 only) 0.97 1 1.03 V TH Input Trip Level, Rising VDD = 4.4V to 28V (MAX1808 only) 1.045 1.1 1.155 V IN1–IN5 Propagation Delay IN1–IN5 rising, 10mV overdrive, VDD = 4.4V 40 TH rising, 10mV overdrive, VDD = 4.4V (MAX1808 only) 11 TH falling, 10mV overdrive, VDD = 4.4V (MAX1808 only) 40 IN1–IN5 Input Leakage Current VIN = 1.5V 0.5 50 nA TH Input Leakage Current VTH = 1.5V (MAX1808 only) 0.5 50 nA ON Input High Logic Level VDD = 4.4V to 28V 0.97 µs µs TH Propagation Delay ON Input Low Logic Level ON Input Leakage Current 2 1.6 V VDD = 4.4V to 28V VON = 5V 0.5 0.03 VON = 28V FAULT Output High Leakage Current V FAULT = 28V (MAX1807 only) FAULT Output Low Voltage ISINK = 4mA (MAX1807 only) 1.2 10 0.01 _______________________________________________________________________________________ V µA 2 µA 0.4 V Micropower Adjustable Overvoltage Protection Controllers (VDD = VON = 15V, VIN1–VIN5 = 0.5V, VTH = 2.0V, CDP = 5nF, FAULT = open, TA = 0°C to +85°C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS VDP = VDD - 0.4V DP Source Current (PMOS Turn-Off) VON = VDD, VIN1 = 1.5V DP Sink Current (PMOS Turn-On) VDP = VDD - 5V DP Pullup Current (PMOS Off) VDP = VDD - 2V, VON = GND, in shutdown state DP Turn-On Clamp Voltage (VDD - VDP) VON = VDD, IDPSINK = 10µA VDP = VDD - 2V MIN TYP 1 50 MAX UNITS µA 5 20 mA 4 50 mA 25 µA VDD = 8.5V to 28V 7.5 9.5 11.5 VDD = 4.4V 3.4 4.1 4.4 V ELECTRICAL CHARACTERISTICS (VDD = VON = 15V, VIN1–VIN5 = 0.5V, VTH = 2.0V, CDP = 5nF, FAULT = open, TA = -40°C to +85°C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS GENERAL VDD Input Voltage Range DP and FAULT in correct state (Table 1) VDD Operating Voltage Range VDD Undervoltage Lockout Threshold Rising trip level, typical 2% hysteresis; when VDD is below this level, DP = Hi and FAULT = Hi-Z 2 28 V 4.4 28 V 2 4.0 V Supply Current VTH = 2V or 0.5V 45 µA Shutdown Current VDD = 15V, VON = GND, VIN1–VIN5 = VTH = GND 8.5 µA V COMPARATORS (IN1–IN5, TH) IN1–IN5 Input Trip Level Rising edge, typical 1% hysteresis 0.95 1.05 TH Input Trip Level, Falling VDD = 4.4V to 28V (MAX1808 only) 0.95 1.05 V TH Input Trip Level, Rising VDD = 4.4V to 28V (MAX1808 only) 1.045 1.155 V IN1–IN5 Input Leakage Current VIN = 1.5V 50 nA TH Input Leakage Current VTH = 1.5V (MAX1808 only) 50 nA ON Input High Logic Level VDD = 4.4V to 28V ON Input Low Logic Level 1.8 V VDD = 4.4V to 28V 0.4 VON = 5V 1.2 VON = 28V 10 FAULT Output High Leakage Current V FAULT = 28V (MAX1807 only) 2 FAULT Output Low Voltage ISINK = 4mA (MAX1807 only) ON Input Leakage Current DP Source Current (PMOS Turn-Off) VON = VDD, VIN1 = 1.5V DP Sink Current (PMOS Turn-On) VDP = VDD - 5V DP Turn-On Clamp Voltage (VDD - VDP) VON = VDD, IDPSINK = 10µA VDP = VDD - 0.4V VDP = VDD - 2V 0.4 V µA µA V µA 1 4 mA 2 mA VDD = 8.5V to 28V 7.5 11.5 VDD = 4.4V 3.4 4.4 V Note 1: Specifications to -40°C are guaranteed by design, not production tested. _______________________________________________________________________________________ 3 MAX1807/MAX1808 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (Typical Operating Circuit, VDD = 15V, TA = +25°C, unless otherwise noted.) SHUTDOWN SUPPLY CURRENT vs. SUPPLY VOLTAGE TA = -40°C 15 TA = +25°C 10 5 4.0 TA = +25°C 3.5 700 3.0 TA = -40°C 2.5 2.0 1.5 TA = +85°C 600 5 10 15 20 25 0 5 10 15 20 25 30 0 4 8 12 16 20 SUPPLY VOLTAGE (V) FAULT OUTPUT SINK CURRENT (mA) NORMALIZED IN_ TRIP THRESHOLD ERROR vs. SUPPLY VOLTAGE NORMALIZED IN_ TRIP THRESHOLD ERROR vs. TEMPERATURE NORMALIZED TH TRIP THRESHOLD ERROR vs. SUPPLY VOLTAGE (TH FALLING) 0.05 TA = +25°C 0 -0.05 TA = -40°C -0.10 -0.15 28V 0 15V -0.1 4.4V -0.2 10 15 20 25 -0.01 -0.02 -50 30 TA = +25°C TA = +85°C 0 TA = -40°C -0.4 -0.25 5 0.01 -0.3 TA = +85°C -0.20 0.1 MAX1807 toc06 0.2 0.02 TRIP THRESHOLD ERROR (%) 0.10 MAX1807 toc05 0.15 0.3 TRIP THRESHOLD ERROR (%) MAX1807 toc04 0 50 0 100 10 20 30 SUPPLY VOLTAGE (V) TEMPERATURE (°C) SUPPLY VOLTAGE (V) NORMALIZED TH TRIP THRESHOLD ERROR vs. TEMPERATURE (TH FALLING) NORMALIZED TH TRIP THRESHOLD ERROR vs. SUPPLY VOLTAGE (TH RISING) NORMALIZED TH TRIP THRESHOLD ERROR vs. TEMPERATURE (TH RISING) 0.05 28V 0 -0.05 4.4V -0.10 0.1 TA = +25°C 0 TA = -40°C -0.1 TA = +85°C -0.2 -0.15 0 50 TEMPERATURE (°C) 100 28V 0.10 4.4V 0.05 0 -0.05 -0.10 -0.15 -0.3 -50 0.15 MAX1807 toc09 0.2 0.20 TRIP THRESHOLD ERROR (%) 0.10 0.3 TRIP THRESHOLD ERROR (%) MAX1807 toc07 0.15 MAX1807 toc08 TRIP THRESHOLD ERROR (%) 200 SUPPLY VOLTAGE (V) 0.20 4 300 TA = -40°C 0 30 0.25 0 TA = +25°C 400 100 0 0 500 1.0 0.5 0 MAX1807 toc03 TA = +85°C 4.5 OUTPUT VOLTAGE (mV) SUPPLY CURRENT (µA) 20 5.0 FAULT OUTPUT VOLTAGE LOW vs. FAULT OUTPUT SINK CURRENT MAX1807 toc02 TA = +85°C SHUTDOWN SUPPLY CURRENT (µA) 25 MAX1807 toc01 SUPPLY CURRENT vs. SUPPLY VOLTAGE TRIP THRESHOLD ERROR (%) MAX1807/MAX1808 Micropower Adjustable Overvoltage Protection Controllers -0.20 0 5 10 15 20 SUPPLY VOLTAGE (V) 25 30 -50 0 50 TEMPERATURE (°C) _______________________________________________________________________________________ 100 Micropower Adjustable Overvoltage Protection Controllers TA = +25°C 30 TA = -40°C 20 10 5 10 15 20 25 40 TA =+25°C 30 14 TA = -40°C 20 0 5 10 15 20 25 12 TA = +25°C 10 TA = -40°C 8 6 4 10mV OVERDRIVE 0 0 30 TA = +85°C 2 10mV OVERDRIVE 0 30 5 10 15 20 25 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) DP SOURCE CURRENT vs. (VDD - VDP) VOLTAGE DP SOURCE CURRENT vs. (VDD - VDP) VOLTAGE DP SINK CURRENT vs. (VDD - VDP) VOLTAGE 20 SOURCE CURRENT (mA) 0.08 0.07 0.06 0.05 0.04 0.03 0.02 60 50 DP SINK CURRENT (mA) 0.09 15 10 30 MAX1807 toc15 25 MAX1807 toc14 0.10 MAX1807 toc13 0 TA = +85°C 10 10mV OVERDRIVE 0 SOURCE CURRENT (mA) 50 PROPAGATION DELAY (µs) 40 16 MAX1807 toc11 TA = +85°C PROPAGATION DELAY (µs) PROPAGATION DELAY (µs) 50 60 MAX1807 toc10 60 TH PROPAGATION DELAY vs. SUPPLY VOLTAGE (TH RISING) TH PROPAGATION DELAY vs. SUPPLY VOLTAGE (TH FALLING) MAX1807 toc12 IN_ PROPAGATION DELAY vs. SUPPLY VOLTAGE 5 40 30 20 10 0.01 0 0.15 0.30 0.45 0.60 0 4 6 8 10 0 12 2 4 6 8 10 12 (VDD - VDP) VOLTAGE (V) (VDD - VDP) VOLTAGE (V) IN_ AND TH BIAS CURRENT vs. TEMPERATURE IN_ MAXIMUM TRANSIENT PULSE DURATION vs. PULSE OVERDRIVE VOLTAGE TH MAXIMUM TRANSIENT PULSE DURATION vs. PULSE OVERDRIVE VOLTAGE 1.0 0.8 0.6 0.4 0.2 0 -15 10 35 TEMPERATURE (°C) 60 85 70 60 50 40 30 70 60 50 40 10 10 0.1 OVERDRIVE VOLTAGE (V) 1 NEGATIVEGOING TRANSIENT 30 20 0.01 MAX1807 toc18 80 20 0 0.001 DP GOES HIGH MOMENTARILY ABOVE THE CURVE 90 PULSE DURATION (µs) 80 PULSE DURATION (µs) 1.2 DP LATCHES (HIGH) ABOVE THE CURVE 90 100 MAX1807 toc17 100 MAX1807 toc16 1.4 -40 2 (VDD - VDP) VOLTAGE (V) 1.6 BIAS CURRENT (nA) 0 0 0 0 0.001 0.01 0.1 1 OVERDRIVE VOLTAGE (V) _______________________________________________________________________________________ 5 MAX1807/MAX1808 Typical Operating Characteristics (continued) (Typical Operating Circuit, VDD = 15V, TA = +25°C, unless otherwise noted.) Micropower Adjustable Overvoltage Protection Controllers MAX1807/MAX1808 Pin Description PIN NAME FUNCTION Overvoltage Detect Comparator Input. When any input exceeds 1V, the fault latch is set. Connect unused inputs to GND. 1–5 IN1–IN5 6 GND 7 ON Logic Input. ON turns on internal reference when high. Logic trip level is approximately 1.2V with 15% hysteresis. When ON is low, the fault latch is reset. ON can be connected directly to VDD at the expense of supply current. 8 DP External P-Channel MOSFET Gate Driver Output. The output high level is VDD. The output low level is VDD - 9.5V or GND, whichever is higher. This output is latched high when an overvoltage condition is detected. 9 VDD Analog Supply Input. Use an external RC filter to eliminate excessive switching noise on VDD. When VDD is less than 2.7V, the fault latch is reset. FAULT Signal Overvoltage Condition Output. This open-drain N-channel output is latched low when an overvoltage condition is detected. (MAX1807 only) 10 TH Ground Input Monitor Comparator. When TH is below 1V, DP goes high to turn off the external P-channel switch. When TH exceeds 1.1V, DP goes low if there is no fault. Between 1V and 1.1V is the hysteresis band where the output state of the TH comparator remains unchanged. (MAX1808 only) Detailed Description The MAX1807/MAX1808 provide overvoltage protection for systems with multiple supply rails. Very low output voltage supplies can have an overvoltage before the power-supply controller has sufficient supply voltage to activate protection circuitry. The MAX1807/MAX1808 offer a system-wide approach to effectively protect the loads and prevent catastrophic events. The MAX1807/MAX1808 are powered directly by the main system input supply. A low output voltage from DP activates a P-channel switch to supply power to the rest of the system. As the rest of the system supplies come up, the MAX1807/MAX1808 monitor each of them for overvoltage conditions and safely disconnect the input from the rest of the system if any supply malfunctions occur due to a shorted MOSFET, shorted copper trace, or malfunctioning supply. Built-in overvoltage detectors in individual power supplies provide redundancy. The MAX1807/MAX1808 drive the main P-channel load switch that powers the system. The driver includes active clamping to safely drive a 12V P-channel MOSFET gate. If overvoltage is detected, the P-channel load switch is turned off and the state is latched. The internal fault latch resets when VDD is less than 2.7V (power cycled) or ON is pulled low (manual reset). When ON is logic low, the P-channel switch is turned off (Table 1). 6 The MAX1808 has a TH input that turns off the P-channel switch if TH goes below 1V without affecting the fault latch. TH output is designed for low-battery detection. The comparator has 10% hysteresis, allowing the battery voltage to rise when the load is removed without reenabling the external P-channel switch. The MAX1807 has a fault alert output (FAULT) instead of the TH input. FAULT is an open-drain output, rated for up to 28V, that directly reflects the state of the internal fault latch. IN1–IN5 Overvoltage Comparators The overvoltage comparators have a 1V trip level. The fault latch is set if any one of the five overvoltage comparators goes above the trip level. A limited input bandwidth ensures that small glitches will not trigger an overvoltage event (see IN_ Maximum Transient Pulse Duration vs. Pulse Overdrive Voltage in the Typical Operating Characteristics). DP PFET Driver Output The MAX1807/MAX1808 have a totem driver (DP) with an active clamp that simplifies driving the external Pchannel load switch. The -9.5V Vgs clamp eliminates complexity in circuits where VDD exceeds the P-channel FET’s maximum gate voltage. DP goes high and turns off the P-channel switch during undervoltage lockout, when ON is low, when TH is less than 1V, or if an overvoltage fault occurs. _______________________________________________________________________________________ Micropower Adjustable Overvoltage Protection Controllers tON = Cgs ✕ R disconnected from the battery. The comparator has a limited bandwidth to ensure that small transients will not shut down the system supplies. Increase TH hysteresis by adding a resistor from TH to one of the voltage rails disconnected by the P-channel load switch, such as the 1.8V supply (Figure 2). Use one of the lower voltage supplies to eliminate the necessity of extremely large resistors to obtain reasonable hysteresis. When the MAX1714 is on, the trip threshold is lower than when the MAX1714 is off, pro- The turn-off time will be the product of the gate-tosource capacitance of the P-channel FET and the DP source current of the MAX1807/MAX1808 (see DP Source Current vs. (VDD - VDP) Voltage in the Typical Operating Characteristics). 1N4148 VDD For very slow turn-off times, adding an external capacitor between the gate and the source of the P-channel FET eliminates the need for resistors with extremely high values. DP R MAX1807 MAX1808 SYSTEM POWER SUPPLIES TH Input Comparator (MAX1808 Only) TH input comparator can disconnect the load from the battery when the battery voltage is too low. The falling trip level is 1V, and the rising trip level is 1.1V. The 100mV hysteresis can prevent the load switch from turning on when the battery voltage rises as the load is Figure 1. External FET Gate Control 2V TO 28V 2V TO 28V 6.5M 6.5M VDD TH VDD DP DP TH 1M 1M MAX1808 MAX1808 MAX1714 GND GND 1.8V OR 0 10M DEFAULT 10% HYSTERESIS VTRIP = 1V + (1µA × 6.5MΩ) = 7.5V VUNTRIP = 1.1V + (1.1µA × 6.5MΩ) = 8.25V ADDING HYSTERESIS VTRIP = 1V + [1µA ✕ (1.8V - 1.0V) / 10MΩ] ✕ 6.5MΩ = 1V + (1µA - 0.08µA) ✕ 6.5MΩ = 1V + (920nA ✕ 6.5MΩ) = 6.98V VUNTRIP = 1.1V + [1.1µA - (0 - 1.1V) / 10MΩ] ✕ 6.5MΩ = 1.1V + (1.1µA + 0.11µA) ✕ 6.5MΩ = 1.1V + (1.21µA ✕ 6.5MΩ) = 8.97V Figure 2. Adding Hysteresis _______________________________________________________________________________________ 7 MAX1807/MAX1808 The DP driver can sink and source significant current and achieves fast turn-on and turn-off times even with large P-channel switches. Adding a resistor in series with DP can increase turn-on and turn-off times. To slow the turn-on time without affecting the turn-off time, add a diode in parallel with the resistor (Figure 1). The turnon time will be the product of the series resistor and the gate-to-source capacitance of the P-channel FET: MAX1807/MAX1808 Micropower Adjustable Overvoltage Protection Controllers Table 1. MAX1807/MAX1808 State Table DP FAULT VDD ON TH IN1–IN5 <2V X X X 2 < VDD < 4.0V X X X HI Hi-Z >4.0V 0 X X HI Hi-Z >4.0V 1 <1V X HI >4.0V 1 >1.1V All <1V LO Hi-Z >4.0V 1 >1.1V Any >1V HI LO COMMENT Undefined Undefined Note that TH has 0.1V hysteresis (MAX1808 only) Only condition for PFET to be turned on viding additional hysteresis. Turning off the chosen supply will change the undervoltage trip levels. FAULT Open-Drain N-Channel Flag Output (MAX1807 Only) Pin Configuration TOP VIEW The MAX1807 has an open-drain N-channel FAULT output. The FAULT output directly reflects the state of the internal fault latch, going low when an overvoltage event occurs. The FAULT output can be used to signal the system power-management microcontroller, trip a resetable fuse, drive an external high-side driver, or for other purposes. IN1 1 Undervoltage Lockout and Power-On Reset (POR) Period Undervoltage lockout holds DP high and FAULT in high impedance until VDD exceeds the VDD undervoltage lockout threshold. When VDD exceeds the undervoltage threshold, the DP and FAULT outputs remain unchanged during the power-on reset period (60µs), allowing the reference and comparators to settle. Normal operation resumes after the POR period. 10 FAULT (TH) IN2 2 IN3 3 IN4 4 7 ON IN5 5 6 GND MAX1807 MAX1808 9 VDD 8 DP µMAX ( ) MAX1808 0NLY Chip Information TRANSISTOR COUNT: 955 PROCESS: BiCMOS 8 _______________________________________________________________________________________ Micropower Adjustable Overvoltage Protection Controllers 5V 2.5V 3.3V CORE 1.8V 6.5M VDD 1M DP TH 402k 0.01µF IN1 1M MAX1808 IN2 IN3 IN4 150k 682k ON GND IN5 150k 121k 150k 150k 150k 261k THRESHOLDS: 1) 3.63V 2) 5.5V 3) 1.85V 4) 2.0V 5) 2.75V 150k _______________________________________________________________________________________ 9 MAX1807/MAX1808 Typical Operating Circuit Micropower Adjustable Overvoltage Protection Controllers 10LUMAX.EPS MAX1807/MAX1808 Package Information 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 © 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.