19-1137; Rev 0; 9/96 4-Pin Micropower Voltage Monitors ____________________________Features ♦ ±1.25% Precision Voltage Threshold ♦ SOT143 Package ♦ Low Cost ♦ <5µA Typical Supply Current ♦ Open-Drain Output (MAX836) Push-Pull Output (MAX837) ________________________Applications ______________Ordering Information Precision Battery Monitor PART* TEMP. RANGE PINMARKING PACKAGE CODE Battery-Powered Systems MAX836EUS-T -40°C to +85°C 4 SOT143 AAEQ Threshold Detectors MAX837EUS-T -40°C to +85°C 4 SOT143 AAER Load Switching *All devices available in tape-and-reel only. Contact factory for availability. __________Typical Operating Circuit __________________Pin Configuration VCC MAX836 ONLY GND OUT GND 1.204V REF MAX836 MAX837 VCC VCC TOP VIEW 4 OUT 3 IN MAX836 MAX837 IN VCC 0.1µF 1 2 SOT-143 ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800 MAX836/MAX837 _______________General Description The MAX836/MAX837 micropower voltage monitors contain a 1.204V precision bandgap reference and a comparator in a SOT143 package. The MAX836 has an open-drain, N-channel output driver, while the MAX837 has a push-pull output driver. Two external resistors set the trip threshold voltage. MAX836/MAX837 4-Pin Micropower Voltage Monitors ABSOLUTE MAXIMUM RATINGS VCC, OUT to GND (MAX836) ....................................-0.3V to 12V IN, OUT to GND (MAX837).........................-0.3V to (VCC + 0.3V) Input Current VCC .................................................................................20mA IN.....................................................................................10mA Output Current, OUT...........................................................20mA Rate of Rise, VCC ............................................................100V/µs Continuous Power Dissipation SOT143 (derate 4mW/°C above +70°C) ......................320mW Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10sec) .............................+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 (VCC = +2.5V to +11.0V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER Operating Voltage Range (Note 1) SYMBOL CONDITIONS VCC TYP 2.5 VIN = 1.16V, OUT = low Supply Current (Note 2) MIN VCC = 3.6V TA = +25°C 3.5 TA = TMIN to TMAX VIN = 1.25V, OUT = high VCC = 3.6V VTH Trip Threshold Voltage Hysteresis VHYST IN Operating Voltage Range (Note 1) VIN falling 11 V 6.5 15 TA = +25°C 2.0 TA = TMIN to TMAX 5.0 µA 8.0 VCC = full operating range Trip Threshold Voltage UNITS 10 VCC = full operating range ICC MAX 13 TA = +25°C 1.185 1.204 1.215 TA = 0°C to +70°C 1.169 1.204 1.231 VCC = 5V, IN = low to high 6 VIN V mV VCC - 1 V ±12 nA IN Leakage Current (Note 3) IIN VIN = VTH ±3 Propagation Delay tPL VCC = 5.0V, 50mV overdrive 80 µs VCC = 5.0V, 100mV overdrive 35 µs Glitch Immunity OUT Rise Time tRT VCC = 5.0V, no load (MAX837 only) 260 ns OUT Fall Time tFT VCC = 5.0V, no load (MAX836 pull-up = 10kΩ) 680 ns Output Leakage Current (Note 4) ILOUT VIN > VTHMAX (MAX836 only) Output Voltage High VOH VIN > VTHMAX, ISOURCE = 500µA (MAX837 only) Output Voltage Low VOL VIN < VTHMIN, ISINK = 500µA Note 1: Note 2: Note 3: Note 4: 2 ±1 VCC - 0.5 The voltage-detector output remains in the direct state for VCC down to 1.2V when VIN ≤ VCC / 2. Supply current has a monotonic dependence on VCC (see Typical Operating Characteristics). IN leakage current has a monotonic dependence on VCC (see Typical Operating Characteristics). The MAX836 open-drain output can be pulled up to a voltage greater than VCC, but may not exceed 11V. _______________________________________________________________________________________ µA V 0.4 V 4-Pin Micropower Voltage Monitors TRIP THRESHOLD VOLTAGE vs. TEMPERATURE 1.204 1.203 3.0 2.0 MAX836/7 03 12 10 VCC = 11V 8 6 4 1.0 1.202 VCC = 3.6V 2 VIN = 1.22V 0 0 20 40 60 80 100 2 3 5 4 0 6 7 8 9 1 0 10 11 12 2 3 4 5 7 6 8 9 10 11 12 TEMPERATURE (°C) VCC (V) VIN (V) IN LEAKAGE CURRENT vs. IN VOLTAGE IN LEAKAGE CURRENT vs. SUPPLY VOLTAGE MAX837 OUTPUT VOLTAGE vs. OUTPUT SOURCE CURRENT 50 40 TA = +25°C 30 20 TA = +85°C 10 3.6 3.2 TA = +25°C 2.8 1 2 3 4 5 6 7 8 9 10 11 3 4 5 TA = -40°C 100 10 1 6 7 8 9 0.1 1 10 OUTPUT SINK CURRENT (mA) 100 MAX836/7-06A TA = +25°C 2.0 1.5 TA = +85°C 0.1 1 10 OUTPUT SOURCE CURRENT (mA) OUTPUT LOW VOLTAGE vs. SUPPLY VOLTAGE SHORT-CIRCUIT SINK CURRENT vs. SUPPLY VOLTAGE MAX836/7 07 120 ISINK = 500µA 110 0.01 10 11 12 100 90 80 70 60 50 40 20 0.01 2.5 0.5 30 0.1 TA = -40°C 3.0 VCC (V) 130 OUTPUT LOW VOLTAGE (mV) MAX836/7-06B TA = +85°C 1000 3.5 0 2 OUTPUT VOLTAGE vs. OUTPUT SINK CURRENT TA = +25°C TA = +85°C VIN = 1.2V VIN (V) 10,000 4.0 1.0 2.0 0 4.5 4.0 2.4 0 5.0 TA = -40°C OUTPUT VOLTAGE (V) 60 4.4 100 70 SHORT-CIRCUIT SINK CURRENT (mA) IN LEAKAGE CURRENT (nA) TA = -40°C 5.5 MAX836/7 05 70 4.8 MAX836/7 04 VCC = 11V MAX836/7 08 -20 80 IN LEAKAGE CURRENT (nA) 14 4.0 SUPPLY CURRENT (µA) 1.205 16 MAX836/7 02 MAX836/7 01 5.0 SUPPLY CURRENT (µA) TRIP THRESHOLD VOLTAGE (V) 1.206 1.201 -60 -40 OUTPUT VOLTAGE (mV) SUPPLY CURRENT vs. IN VOLTAGE SUPPLY CURRENT vs. SUPPLY VOLTAGE 1.207 TA = -40°C 60 50 TA = +25°C 40 30 TA = +85°C 20 10 0 2 3 4 5 6 7 8 VCC (V) 9 10 11 12 2 3 4 5 6 7 8 9 10 11 12 VCC (V) _______________________________________________________________________________________ 3 MAX836/MAX837 __________________________________________Typical Operating Characteristics (VCC = +5V, RLOAD = 1MΩ, RPULL-UP = 10kΩ (MAX836 only), TA = +25°C, unless otherwise noted.) ____________________________Typical Operating Characteristics (continued) (VCC = +5V, RLOAD = 1MΩ, RPULL-UP = 10kΩ (MAX836 only), TA = +25°C, unless otherwise noted.) VCC FALLING PROPAGATION DELAY vs. TEMPERATURE OUT RISE/FALL TIME vs. SUPPLY VOLTAGE MAX836/7 10 140 VTRIP = 4.63V 1mV/µs 1800 MAX836/7 09 160 1600 1400 120 100 1200 VTRIP = 3.0V 10mV/µs 80 VTRIP = 4.63V 60 VTRIP = 3.0V RISE TIME MAX837 ONLY 1000 800 FALL TIME 600 400 40 -60 -40 -20 200 0 0 20 40 60 80 100 TEMPERATURE (°C) PIN NAME 1 GND System Ground 2 VCC System Supply Input 3 IN 4 OUT FUNCTION Noninverting Input to the Comparator. The inverting input connects to the internal 1.204V bandgap reference. Open-Drain (MAX836) or Push-Pull (MAX837) Output RPULL-UP OUT 4 5 6 7 8 9 10 11 12 _______________Detailed Description The MAX836/MAX837 micropower voltage monitors contain a 1.204V precision bandgap reference and a comparator (see the Typical Operating Circuit ). The only difference between the two parts is the structure of the comparator output driver. The MAX836 has an open-drain N-channel output driver that can be pulled up to a voltage higher than VCC, but under 11V. The MAX837’s output is push-pull, and can both source and sink current. Two external resistors set the trip voltage, VTRIP (Figure 1). VTRIP is the point at which the applied voltage (typically VCC) toggles OUT. The MAX836/MAX837’s high input impedance allows large-value resistors without compromising trip-voltage accuracy. To minimize current consumption, select a value for R2 between 500kΩ and 1MΩ, then calculate R1 as follows: V R1 = R2 TRIP - 1 VTH MAX836 VCC 3 Programming the Trip Voltage VCC GND 2 VCC (V) _____________________Pin Description VCC TIME (ns) PROPAGATION DELAY (µs) MAX836/MAX837 4-Pin Micropower Voltage Monitors where VTRIP = desired trip voltage (in volts), VTH = threshold trip voltage (1.204V). IN 0.1µF __________Applications Information VTRIP = (1.204) R1 + R2 R2 R1 NOTE: UNITS ARE OHMS AND VOLTS Figure 1. Programming the Trip Voltage, VTRIP 4 R2 Adding Hysteresis Hysteresis adds noise immunity to the MAX836/MAX837 and prevents repeated triggering when VIN is near the threshold trip voltage. Figure 2 shows how to add hysteresis to the comparator. The technique is similar for _______________________________________________________________________________________ 4-Pin Micropower Voltage Monitors Monitoring Voltages Other than VCC The MAX836/MAX837 can monitor voltages other than VCC (Figure 3). Calculate VTRIP as shown in the section Programming the Trip Voltage. The monitored voltage (VMON) is independent of VCC. VIN must be 1V less than VCC. Determine the thermistor’s resistance (R2) at the desired temperature. Then, using R2’s resistance and half the resistance of R3, calculate R1’s value with the following formula: V R1 = (R2 + R3) CC - 1 1.204 ___________________Chip Information TRANSISTOR COUNT: 54 Heater Temperature Control Figure 4 shows a basic heater temperature-control circuit. Upon power-up, OUT is high and the N-channel MOSFET turns on. Current flows through the heating element (R4), warming the surrounding area. R2 is a negative-temperature-coefficient thermistor and as temperature increases, its resistance decreases. As the thermistor heats up and its resistance decreases, the MAX837’s voltage at IN decreases until it reaches the 1.204V threshold voltage. At this point, OUT goes low, turning off the heating element. The thermistor cools and the voltage at IN rises until it overcomes the MAX837’s hysteresis (6mV). OUT returns high when this point is reached, turning on the heating element again. This cycle repeats as long as power is applied. OUT GND VMON MAX837 R1 VCC VCC IN 0.1µF R2 Figure 3. Monitoring Voltages Other than VCC VCC OUT GND OUT 0.1µF R1 R3 MAX837 VCC VCC VCC IN THERMISTOR WITH NEGATIVE COEFFICIENT IN MAX837 T HEATING ELEMENT R4 R3 R1 0.1µF R2 R2 C1 GND NOTE: C1 ADDS ADDITIONAL NOISE IMMUNITY Figure 2. Adding Hysteresis to the Comparator OUT R1 = (R2 + R3) VCC - 1)Ω ( 1.204 Figure 4. Heater Temperature Control _______________________________________________________________________________________ 5 MAX836/MAX837 both parts. For the MAX836, select the ratio of resistors R1 and R2 so that IN sees 1.204V when the monitor voltage falls to or rises above the desired trip point (VTRIP). R3 adds hysteresis and is typically an order of magnitude larger than R1 or R2. The current through R1 and R2 should be at least 500nA to ensure that the 12nA maximum input current does not shift the trip point significantly. Capacitor C1 adds additional noise rejection. MAX836/MAX837 4-Pin Micropower Voltage Monitors __________________________________________________Tape-and-Reel Information 4.0 ±0.1 1.0 ±0.1 1.75 ±0.1 2.0 ±0.05 1.5 +0.1/-0.0 DIAMETER A 3.5 ±0.05 8.0 ±0.3 2.2 ±0.1 0.5 RADIUS TYPICAL A0 4.0 ±0.1 MARKING INFORMATION † LOT S CODE XX XX 1.0 MINIMUM A Bo Ko 0.30 ±0.05 0.8 ±0.05 Ao = 3.1mm ±0.1 Bo = 2.7mm ±0.1 Ko = 1.2mm ±0.1 NOTE: DIMENSIONS ARE IN MM. AND FOLLOW EIA481-1 STANDARD. 0.30R MAX. † AM = MAX8 AN = MAX8 AP = MAX8 AQ = MAX8 AR = MAX8 AS = MAX8 AT = MAX81 ________________________________________________________Package Information DIM D 0°-8° A C I A1 e1 B A A1 B B1 C D E e e1 H I INCHES MIN MAX 0.031 0.001 0.014 0.030 0.0034 0.105 0.047 0.070 0.071 0.082 0.004 0.047 0.005 0.022 0.038 0.006 0.120 0.055 0.080 0.079 0.098 0.012 MILLIMETERS MIN MAX 0.787 0.025 0.356 0.762 0.086 2.667 1.194 1.778 1.803 2.083 0.102 1.194 0.127 0.559 0.965 0.152 3.048 1.397 2.032 2.007 2.489 0.305 21-0052A E H 4-PIN SOT143 SMALL-OUTLINE TRANSISTOR PACKAGE B1 e 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. 6 ___________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600 © 1996 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.