MAX6710OUT

19-2324; Rev 0; 1/02 Low-Voltage, High-Accuracy, Quad-Voltage µP Supervisory Circuit in SOT Package The MAX6710 is available in a small 6-pin SOT23 package and operates over the extended (-40°C to +85°C) temperature range. ________________________Applications Telecommunications Features ♦ Monitors Four Power-Supply Voltages ♦ Precision Factory-Set Reset Threshold Options for 5.0V, 3.3V, 3.0V, 2.5V, and 1.8V Supplies ♦ Adjustable Voltage Threshold Monitors Down to 0.62V with 1.5% Accuracy ♦ Low 35µA Supply Current ♦ Open-Drain RESET Output with 10µA Internal Pullup ♦ 140ms (min) Reset Timeout Period ♦ RESET Valid to IN1 = 1V or IN2 = 1V ♦ Immune to Short Monitored Supply Transients ♦ Guaranteed from -40°C to +85°C ♦ Small 6-Pin SOT23 Package Ordering Information PART TEMP RANGE PIN-PACKAGE MAX6710_UT-T* -40°C to +85°C 6 SOT23-6 *Insert the desired suffix letter from the Selector Guide into the blank to complete the part number. There is a 2500 piece minimum order increment requirement on the SOT package and these devices are available in tape-and-reel only. High-End Printers Desktop and Network Computers Typical Operating Circuit Data Storage Equipment Networking Equipment Industrial Equipment Set-Top Boxes IN1 SUPPLIES TO BE MONITORED MAX6710 IN2 RESET µP IN3 IN4 Selector Guide appears at end of data sheet. GND 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 MAX6710 General Description The MAX6710 precision quad-voltage monitor with microprocessor (µP) supervisory reset timing monitors up to four system-supply voltages and asserts a single reset if any supply voltage drops below its preset threshold. The device significantly reduces system size and component count while improving reliability compared to separate ICs or discrete components. A variety of factory-trimmed threshold voltages are available to accommodate different supply voltages and tolerances with minimal external component requirements. The selection includes internally fixed options for monitoring 5.0V, 3.3V, 3.0V, 2.5V, and 1.8V supplies with -5% or -10% tolerances. The device is also available with one to three adjustable threshold options to monitor voltages down to 0.62V. A single active-low reset output asserts when any monitored input is below its associated threshold. The output is open drain with a weak internal pullup (10µA) to IN2. Reset remains low for a reset timeout period (140ms min) after all voltages are above the selected thresholds. The output is valid as long as either the IN1 or IN2 input voltage remains >1V. MAX6710 Low-Voltage, High-Accuracy, Quad-Voltage µP Supervisory Circuit in SOT Package ABSOLUTE MAXIMUM RATINGS Terminal Voltage (with respect to GND) Input Voltages (IN_ ).................................................-0.3V to +6V RESET.......................................................................-0.3V to +6V Continuous RESET Current .................................................20mA Continuous Power Dissipation (TA = +70°C) 6-Pin SOT23 (derate 8.7mW/°C above +70°C).........695.7mW Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Junction Temperature ......................................................+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 (VIN2 = 1V to 5.5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VIN2 = 3.0V to 3.3V, TA = +25°C.) (Note 1) PARAMETER Operating Voltage Range (Notes 2, 3) Input Current SYMBOL VCC VIN2 IIN_ ICC Threshold Voltage VTH CONDITIONS MIN MAX6710Q All others 2 VTH Reset Threshold Hysteresis VHYST Reset Threshold Temperature Coefficient TCVTH IN_ to Reset Delay tRD Reset Timeout Period tRP MAX 2.0 5.5 TA = 0oC to +85oC 1.0 5.5 o 1.2 5.5 o TA = -40 C to +85 C IN_ = nominal input voltage (for 1.8V, 2.5V, and 5.0V supplies) 25 40 IN2 = nominal input voltage (for 3.0V and 3.3V supplies) (Note 4) 55 115 0.4 VIN3, VIN4 = 0 to 0.85V (for adjustable thresholds) 0.2 MAX6710Q only, VCC = 5.5V IN_ decreasing 35 50 5V (-5%) 4.50 4.63 4.75 5V (-10%) 4.25 4.38 4.50 3.3V (-5%) 3.00 3.08 3.15 3.3V (-10%) 2.85 2.93 3.00 3.0V (-5%) 2.70 2.78 2.85 3.0V (-10%) 2.55 2.63 2.70 2.5V (-5%) 2.25 2.32 2.38 2.5V (-10%) 2.13 2.19 2.25 1.8V (-5%) 1.62 1.67 1.71 IN_ decreasing UNITS V µA VIN1 = 0 to 0.85V (for adjustable thresholds) 1.8V (-10%) Adjustable Threshold TYP 1.53 1.58 1.62 0.611 0.620 0.624 IN_ increasing relative to IN_ decreasing VIN_ falling at 10mV/µs from VTH to (VTH - 50mV) V 0.3 %VTH 60 ppm/oC 30 140 V 200 _______________________________________________________________________________________ µs 280 ms Low-Voltage, High-Accuracy, Quad-Voltage µP Supervisory Circuit in SOT Package MAX6710 ELECTRICAL CHARACTERISTICS (continued) (VIN2 = 1V to 5.5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VIN2 = 3.0V to 3.3V, TA = +25°C.) (Note 1) PARAMETER SYMBOL RESET Output Low VOL MIN VOH RESET Output High Source Current MAX 0.3 VIN2, VCC = 2.5V, ISINK = 1.2mA 0.4 VIN2 = 1.0V, ISINK = 50µA, TA = 0oC to +85oC 0.3 UNITS V 0.8 ✕ VCC V VIN2 ≥ 2.0V, ISOURCE = 6µA, RESET deasserted 0.8 ✕ VIN2 VIN2 ≥ 2.0V, RESET deasserted IOH TYP VIN2, VCC = 5V, ISINK = 2mA VCC ≥ 2.0V, ISOURCE = 6µA, RESET deasserted (MAX6710Q) RESET Output High Note 1: Note 2: Note 3: Note 4: CONDITIONS 10 µA 100% production tested at TA = +25°C. Limits over temperature guaranteed by design. The device is powered from input IN2 or VCC (for MAX6710Q). The RESET output is guaranteed to be in the correct state for IN1 or IN2 down to 1V. Monitored IN2 voltage (3.3V, 3.0V) is also the device power supply. Supply current splits as follows: 25µA for the resistor divider (for the monitored voltage) and 30µA for other circuits. Typical Operating Characteristics (VIN2 = 3.0V, TA = +25°C) VIN2 = 3.3V 52 50 48 VIN2 = 3V 46 70 60 50 40 30 44 20 42 10 40 -15 10 35 TEMPERATURE (°C) 60 85 0.08 VIN2 = 3.3V 0.06 0.04 VTH = 1.8V 0.02 0 -0.02 -0.04 -0.06 -0.08 -0.10 0 -40 0.10 NORMALIZED THRESHOLD ERROR (%) 54 80 IN2 INPUT CURRENT (µA) 56 MAX6710 toc02 58 IN2 INPUT CURRENT (µA) 90 MAX6710 toc01 60 NORMALIZED THRESHOLD ERROR vs. TEMPERATURE IN2 INPUT CURRENT vs. IN2 VOLTAGE MAX6710 toc03 IN2 INPUT CURRENT vs. TEMPERATURE 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 IN2 VOLTAGE (V) -40 -15 10 35 60 85 TEMPERATURE (°C) _______________________________________________________________________________________ 3 Typical Operating Characteristics (continued) (VIN2 = 3.0V, TA = +25°C) 80 MAX6710 toc05 90 MAX6710 toc06 100 MAX6710 toc04 100 RESET PULLUP AND PULLDOWN RESPONSE (CL = 47pF) RESET DELAY vs. RESET THRESHOLD OVERDRIVE (IN_ DECREASING) MAXIMUM IN_ TRANSIENT DURATION vs. RESET THRESHOLD OVERDRIVE 90 80 IN_ 100mV/div AC-COUPLED 70 70 RESET DELAY (µs) MAXIMUM IN_ TRANSIENT DURATION (µs) 60 50 RESET ASSERTED ABOVE THIS LINE 40 30 60 50 40 RESET 2V/div 30 20 20 10 10 0 0 10µs/div 0 100 200 300 400 500 600 700 800 900 1000 0 100 200 300 400 500 600 700 800 900 1000 RESET THRESHOLD OVERDRIVE (mV) RESET THRESHOLD OVERDRIVE (mV) RESET TIMEOUT DELAY vs. TEMPERATURE RESET TIMEOUT DELAY (ms) 232 231 230 229 228 227 226 225 224 223 222 221 220 RESET TIMEOUT DELAY MAX6710 toc08 MAX6710 toc07 MAX6710 Low-Voltage, High-Accuracy, Quad-Voltage µP Supervisory Circuit in SOT Package IN_ 2V/div RESET 2V/div -40 -15 10 35 60 85 40ms/div TEMPERATURE (°C) Pin Description PIN NAME 1 IN1 Input Voltage 1. See Selector Guide for monitored voltages. IN2 VCC Input Voltage 2. See Selector Guide for monitored voltages. IN2 is the power-supply input for the device. VCC is the power-supply input for the device and is not a monitored voltage (MAX6710Q only). 3 IN3 Input Voltage 3. See Selector Guide for monitored voltages. 4 IN4 Input Voltage 4. See Selector Guide for monitored voltages. 5 GND 6 RESET 2 4 FUNCTION Ground Reset Output, Active Low. RESET goes low when any input goes below its specified threshold. After all inputs are above their threshold voltage, RESET remains low for at least 140ms (minimum) before going high. RESET output is open-drain with a weak internal pullup to IN2, VCC. _______________________________________________________________________________________ Low-Voltage, High-Accuracy, Quad-Voltage µP Supervisory Circuit in SOT Package MAX6710 ALL DEVICES ARE POWERED FROM IN2, VCC (3.0V/3.3V). RESET IS VALID IF VIN1 OR VIN2 IS GREATER THAN 1V, OR IF VCC IS GREATER THAN 2V (MAX6710Q ONLY) IN1 (ADJ) MAX6710 IN2, VCC (3.3V/3V) IN2, VCC RESET TIMEOUT (200ms) NOR GATE IN3 (2.5V/1.8V) UVLO IN4 (ADJ) 0.62V REFERENCE Figure 1. MAX6710 Functional Diagram Detailed Description The MAX6710 is a very small, low-power, quad-voltage µP supervisory circuit designed to maintain system integrity in multisupply systems (Figure 1). The device offers several internally trimmed undervoltage threshold options that minimize the need for external components. Preset voltage monitoring options for 5.0V, 3.3V, 3.0V, 2.5V, and 1.8V make the device ideal for telecom- munications, desktop and notebook computers, highend printers, data storage equipment, and networking equipment applications. The quad-voltage reset includes an accurate bandgap reference, four precision comparators, and a series of internally trimmed resistor-divider networks to set the factory-fixed reset threshold options. The resistor networks scale the specified IN_ reset voltages to match the inter- _______________________________________________________________________________________ 5 MAX6710 Low-Voltage, High-Accuracy, Quad-Voltage µP Supervisory Circuit in SOT Package nal bandgap reference/comparator voltage. Adjustable threshold options bypass the internal resistor networks and connect directly to one of the comparator inputs (an external resistor-divider network is required for threshold matching). The MAX6710Q provides a separate unmonitored power-supply input (VCC) and three adjustable voltage inputs. Each of the internal comparators has a typical hysteresis of 0.3% with respect to its reset threshold. This builtin hysteresis improves the monitor’s immunity to ambient noise without significantly reducing threshold accuracy when an input sits at its specified reset voltage. The MAX6710 is also designed to ignore short IN_ transients. See Typical Operating Characteristics for a glitch immunity graph. Applications Information IN_ VTH_ VTH_ RESET 90% 10% tRP tRD Figure 2. RESET Output Timing Diagram +5V IN2 = +3.3V Reset Output The MAX6710 RESET output asserts low when any monitored IN_ voltage drops below its specified reset threshold and remains low for the reset timeout period (140ms minimum) after all inputs exceed their thresholds (Figure 2). The output is open drain with a weak internal pullup to the monitored IN2 or V CC supply (10µA typ). For many applications no external pullup resistor is required to interface with other logic devices. An external pullup resistor to any voltage from 0 to 5.5V can overdrive the internal pullup if interfacing to different logic-supply voltages (Figure 3). Internal circuitry prevents reverse current flow from the external pullup voltage to IN2. The MAX6710 is normally powered from the monitored IN2 supply when all input voltages are above their specified thresholds. When any supply drops below its threshold, the reset output is asserted and guaranteed to remain low while either IN1 or IN2 is above 1.0V. Adjustable Thresholds The MAX6710 offers several monitor options with adjustable reset thresholds. The threshold voltage at each adjustable IN_ input is typically 0.62V. To monitor a voltage >0.62V, connect a resistor-divider network to the circuit as shown in Figure 4. 100kΩ IN2 VCC RESET RESET MAX6710 GND GND Figure 3. Interfacing to Different Logic-Supply Voltage VINTH R1 R2 VINTH = 0.62V x (R1 + R2) / R2 VREF = 0.62V or, solved in terms of R1: R1 = R2 ((VINTH / 0.62V) - 1) 6 R1 = R2 Figure 4. Setting the Auxiliary Monitor _______________________________________________________________________________________ VINTH - 1) ( 0.62V Low-Voltage, High-Accuracy, Quad-Voltage µP Supervisory Circuit in SOT Package IN1 IN2 MAX6710 IN3 Adding Manual Reset Capability RESET R1 IN4 (ADJUSTABLE INPUT) R2 GND Figure 5. Adding Manual Reset Capability Figure 5 shows an application circuit adding manual reset to the MAX6710 quad-voltage supervisor. Depressing the pushbutton switch short-circuits the analog input to ground and initiates a RESET pulse. The switch must be open for 200ms (typ) in order to deassert the RESET output. No external switch debounce is required. Use a small capacitor to improve noise immunity when using long leads from the pushbutton switch to the adjustable input. Power-Supply Bypassing and Grounding Because the MAX6710 has a guaranteed input current of ±0.2µA (±0.4µA for IN1) on its adjustable inputs, resistor values up to 100kΩ can be used for R2 with