LTC6702 Tiny Micropower, Low Voltage Dual Comparators FEATURES DESCRIPTION n The LTC®6702 is an extremely small dual comparator designed to maximize battery life while providing both speed and low voltage operation in applications where board space is a premium. n n n n n n n n Low Supply Operation: 1.7V Minimum Low Supply Current: 30μA/Comparator Maximum Propagation Delay: 500ns Maximum (–40°C to 125°C) 3.2MHz Toggle Frequency Input Voltage Range Extends 100mV Below Ground Internal Hysteresis: 4mV High Output Drive: TTL and CMOS Compatible Specified at ±15mA (–40°C to 125°C), Capacitive Load Handling to 10,000pF Specified for –40°C to 125°C Temperature Range Available in SOT-23 and 2mm × 2mm DFN Package The LTC6702 is available in the 8-pin SOT-23 and the tiny 2mm × 2mm DFN package. APPLICATIONS n n n n n These comparators operate on supplies between 1.7V and 5.5V, and have a maximum guaranteed propagation delay of 500ns while drawing only 30μA maximum quiescent current. Internal hysteresis desensitizes the LTC6702 to input noise and makes it easy to use, even with slow moving signals. CMOS inputs allow the use of large source impedances. L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Battery Powered Systems Window Comparators Threshold Detectors/Discriminators Clock Regeneration Automotive Sensing and Controls TYPICAL APPLICATION Clock Regeneration Circuit Propagation Delay vs Input Overdrive V + = 3V LT6650 IN VR = 400mV REFERENCE 0.1MF + 1/2 LTC6702 OUT C1 0.1MF – – 1k RECOVERED CLOCK (UP TO 3.2MHz) + FB PROPAGATION DELAY (ns) 600 CLOAD = 10pF V+ = 5V VSTEP = 100mV TA = 25°C 500 FALLING 400 RISING 300 200 6702 TA01 CLOCK INPUT > 100mVP-P 100 0 10 50 60 20 30 40 INPUT OVERDRIVE (mV) 70 80 6702 TA01b 6702f 1 LTC6702 ABSOLUTE MAXIMUM RATINGS (Note 1) Supply Voltage (V+ to GND) ........................................6V Input Voltage...............................................................6V Input Current........................................................–10mA Output Short-Circuit Duration (Note 2) ............ Indefinite Operating Temperature Range (Note 3) LTC6702C ...........................................–40°C to 85°C LTC6702I .............................................–40°C to 85°C LTC6702H .........................................–40°C to 125°C Specified Temperature Range (Note 4) LTC6702C ............................................... 0°C to 70°C LTC6702I .............................................–40°C to 85°C LTC6702H .........................................–40°C to 125°C Junction Temperature .......................................... 150°C Storage Temperature Range...................–65°C to 150°C Lead Temperature (Soldering, 10 sec) TSOT Packages ................................................. 300°C PIN CONFIGURATION TOP VIEW –IN A 2 +IN A 3 GND 4 TOP VIEW 8 V+ OUT A 1 9 OUT A –IN A +IN A GND 7 OUT B A B 6 –IN B 5 +IN B DC PACKAGE 8-LEAD (2mm × 2mm) PLASTIC DFN TJMAX = 150°C, θJA = 102°C/W EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB V+ OUT B –IN B +IN B TS8 PACKAGE 8-LEAD PLASTIC TSOT-23 TJMAX = 150°C, θJA = 130°C/W ORDER INFORMATION Lead Free Finish TAPE AND REEL (MINI) TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION LTC6702CDC#TRMPBF LTC6702CDC#TRPBF LCZJ 8-Lead (2mm × 2mm) Plastic DFN LTC6702IDC#TRMPBF LTC6702IDC#TRPBF LCZJ 8-Lead (2mm × 2mm) Plastic DFN LTC6702HDC#TRMPBF LTC6702HDC#TRPBF LCZJ 8-Lead (2mm × 2mm) Plastic DFN LTC6702CTS8#TRMPBF LTC6702CTS8#TRPBF LTCZK 8-Lead Plastic TSOT-23 LTC6702ITS8#TRMPBF LTC6702ITS8#TRPBF LTCZK 8-Lead Plastic TSOT-23 LTC6702HTS8#TRMPBF LTC6702HTS8#TRPBF LTCZK 8-Lead Plastic TSOT-23 TRM = 500 pieces. *Temperature grades are identified by a label on the shipping container. Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ TEMPERATURE RANGE 0°C to 70°C –40°C to 85°C –40°C to 125°C 0°C to 70°C –40°C to 85°C –40°C to 125°C 6702f 2 LTC6702 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full specified temperature range, otherwise specifications are at TA = 25°C. V+ = 3V, VCM = 1.5V, COUT = 20pF, unless otherwise noted. SYMBOL PARAMETER CONDITIONS V+ Supply Voltage Guaranteed by PSRR Supply Current per Comparator V+ = 3V I+ MIN l l VOS Input Offset Voltage (Note 5) LTC6702C/LTC6702I LTC6702H l l VHYST Input Hysteresis Voltage (Note 5) LTC6702C/LTC6702I LTC6702H l l ΔVOS /ΔT Input Offset Voltage Drift (Note 5) l IIN Input Leakage Current LTC6702C/LTC6702I LTC6702H l l CMRR 1.7 l V+ = 5V TYP 2.5 1.6 1.6 MAX UNITS 5.5 V 24 30 40 μA μA 25 32 42 μA μA 1 3.5 5 6 mV mV mV 4.3 6.2 7.2 8.2 mV mV mV 6 μV/°C 0.001 1 10 nA nA nA Common Mode Rejection Ratio VCM = –0.1V to VDD – 1.2V Input Voltage Range Guaranteed by CMRR PSRR Power Supply Rejection Ratio V + = 1.7V to 5.5V, VCM = 0.5V VOL Output Swing Low Overdrive = 20mV (Note 6) ISINK = 100μA ISINK = 15mA l l 10 250 mV mV mV Overdrive = 20mV (Note 6) ISOURCE = 100μA ISOURCE = 15mA l l 10 350 mV mV mV 450 500 ns ns VOH Output Swing High l 58 56 l –0.1 l 56 54 70 dB dB VDD – 1.2 65 V dB dB tPD Propagation Delay (Note 7) ΔtPD Differential Propagation Delay Between Channels tSKEW Propagation Delay Skew Between tPDLH /tPDHL tr Output Rise Time tf Output Fall Time 15 ns fMAX Maximum Toggle Frequency 3.2 MHz ±250 mA ISC Short-Circuit Current V + = 5V Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: A heat sink may be required to keep the junction temperature below absolute maximum. This depends on the power supply voltage and how many comparators are shorted. The θJA specified for the DC and TS packages is with minimal PCB heat spreading metal. Using expanded metal area on all layers of a board reduces this value. Note 3: The LTC6702C and LTC6702I are guaranteed functional over the temperature range of –40°C to 85°C. The LTC6702H is guaranteed functional over the operating temperature range of –40°C to 125°C. Note 4: The LTC6702C is guaranteed to meet specified performance from 0°C to 70°C. The LTC6702C is designed, characterized and expected to l 320 4 ns 4 ns 11 ns meet specified performance from –40°C to 85°C but is not tested or QA sampled at these temperatures. The LTC6702I is guaranteed to meet specified performance from –40°C to 85°C. The LTC6702H is guaranteed to meet specified performance from –40°C to 125°C. Note 5: The LTC6702 comparators include internal hysteresis. The offset voltage is defined as the average of the input voltages (trip points) required to change the output in each direction minus VCM , while the hysteresis voltage is the difference of these trip points. Note 6: Output voltage swings are measured between the output and power supply rails. Note 7: Propagation delay is for 200mV steps, and 50mV of overdrive. Overdrive is measured relative to the positive and negative trip points. 6702f 3 LTC6702 TYPICAL PERFORMANCE CHARACTERISTICS Supply Current vs Supply Voltage Supply Current vs Temperature 40 125°C 25°C –55°C 20 10 0 1 2 3 4 SUPPLY VOLTAGE (V) 5 30 V+ = 5V 25 V+ = 1.7V 20 15 10 5 6 50 25 75 0 TEMPERATURE (°C) 100 6702 G01 SUPPLY CURRENT PER COMPARATOR (μA) INPUT OFFSET CURRENT (pA) 125°C 85°C 25°C –55°C 80 70 60 50 40 30 20 10 0 –1 3 2 1 4 INPUT VOLTAGE (V) 0 6 5 VSTEP = 200mV 400 OVERDRIVE = 100mV TA = 25°C 350 NO CLOAD –1 4 V+ = 5V 250 V+ = 3V 200 150 100 50 100k 1M TOGGLE RATE (Hz) HYSTERESIS (mV) 125°C 5 25°C 4 –55°C 3 2 –3 1 –4 0 1 2 V+ = 3V 4 5 3 SUPPLY VOLTAGE (V) 6 6702 G07 V+ = 5V 3 V+ = 1.7V 50 25 75 0 TEMPERATURE (°C) 100 125 6702 G06 V+ 6 –2 6 5 Input Common Mode Limits vs Temperature 7 –1 3 2 1 4 INPUT VOLTAGE (V) VSTEP = 200mV OVERDRIVE = 100mV CLOAD = 10pF 2 –50 –25 10M 25°C –55°C 0 V+ = 1.7V 8 125°C 85°C 6702 G03 Hysteresis vs Supply Voltage 1 –5 –55°C 0 6702 G05 4 INPUT OFFSET VOLTAGE (mV) 125 300 0 10k 5 0 1 –1 450 Input Offset Voltage vs Supply Voltage 2 2 Maximum Toggle Rate vs Temperature 6702 G04 3 125°C 3 Supply Current vs Toggle Rate V+ = 3V 90 4 6702 G02 Input Offset Current vs Input Voltage 100 V+ = 3V 25°C 0 –50 –25 INPUT COMMON MODE LIMITS (V) 0 5 V+ = 3V MAXIMUM TOGGLE RATE (MHz) 30 35 INPUT LEAKAGE CURRENT (nA) SUPPLY CURRENT PER COMPARATOR (μA) SUPPLY CURRENT PER COMPARATOR (μA) 50 Input Leakage Current vs Input Voltage 1 2 3 5 4 SUPPLY VOLTAGE (V) 6 6702 G08 V+ –0.5 V+ –1.0 V+ –1.5 GND –0.5 –1.0 –50 –25 50 25 75 0 TEMPERATURE (°C) 100 125 6702 G09 6702f 4 LTC6702 TYPICAL PERFORMANCE CHARACTERISTICS Propagation Delay vs Load Capacitance Propagation Delay vs Supply Voltage 380 360 340 RISING 320 FALLING RISING 280 600 100 500 V+ = 1.7V FALLING 400 RISING 300 FALLING 300 1000 3 5 4 SUPPLY VOLTAGE (V) 100 1000 LOAD CAPACITANCE (pF) 6702 G10 TA = 25°C OUTPUT VOLTAGE (V+-VOUT) (V) OUTPUT VOLTAGE (V) V+ = 1.7V V+ = 3V V+ = 5V 0.01 10 0.1 1 10 SINK CURRENT (mA) 100 100 1000 LOAD CAPACITANCE (pF) Output Voltage vs Temperature 90 TA = 25°C V+ = 1.7V 80 V+ = 3V 0.1 V+ = 5V 0.01 0.001 0.1 1 10 SOURCE CURRENT (mA) 6702 G13 100 HIGH = V+ – VOUT IOUT = ±4mA HIGH 70 60 50 LOW V+ = 1.7V 40 HIGH 30 LOW 20 V+ = 5V 0 –50 –25 0 25 50 75 TEMPERATURE (°C) 6702 G14 Propagation Delay 10000 6702 G12 10 0.001 V+ = 1.7V V+ = 3V V+ = 5V 1 10000 Output High Voltage vs Load Current 1.0 0.1 tf 6702 011 Output Low Voltage vs Load Current 1.0 tf tr RISING V+ = 3V, 5V 10 6 tf tr tr 10 200 2 1 VSTEP = 100mV OVERDRIVE = 50mV TA = 25°C FALLING OUTPUT VOLTAGE (mV) PROPAGATION DELAY (ns) 400 800 VSTEP = 100mV OVERDRIVE = 50mV 700 TA = 25°C 25°C, 125° –55°C TIME (ns) VSTEP = 100mV CLOAD = 10pF PROPAGATION DELAY (ns) 420 Output Rise and Fall Times vs Load Capacitance 100 125 6702 G15 Propagation Delay with Load 1MHz Sinusoid Response 10k VOUT 1V/DIV VOUT 1V/DIV VOUT 1V/DIV GND GND GND VIN 50mV/DIV VIN 50mV/DIV VIN 50mV/DIV 200Ω 100ns/DIV V+ = 3V CL = 20pF VCM = 500mV 6702 G16 V+ = 3V CL = 20pF 100ns/DIV VCM = 500mV RL = 10k, 200Ω 6702 G17 200ns/DIV 6702 G18 V+ = 3V CL = 20pF VCM = 500mV 6702f 5 LTC6702 PIN FUNCTIONS OUT A (Pin 1): Output of Comparator A. –IN B (Pin 6): Inverting Input of Comparator B. –IN A (Pin 2): Inverting Input of Comparator A. OUT B (Pin 7): Output of Comparator B. +IN A (Pin 3): Noninverting Input of Comparator A. V+ (Pin 8): Positive Supply Voltage GND (Pin 4): Ground. Exposed Pad (Pin 9, DC Package Only): Ground. The Exposed Pad must be soldered to PCB. +IN B (Pin 5): Noninverting Input of Comparator B. SIMPLIFIED SCHEMATIC V+ +IN 750Ω –IN 750Ω OUT GND 6702 SS 6702f 6 LTC6702 APPLICATIONS INFORMATION The LTC6702 device is a fast (500ns delay), low power, low voltage (1.7V to 5.5V supply) general purpose dual comparator. It provides rail-to-rail outputs able to interface to TTL/CMOS, draws low supply currents (30μA/comparator), and has internal hysteresis (approximately 4mV). Hysteresis Each comparator has built-in hysteresis to simplify designs, to insure stable operation in the presence of noise at the inputs, and to reject supply rail noise. The reference voltage applied to the input is not the exact switching threshold value due to the built-in hysteresis. Actual output switching typically occurs within ±2.2mV of the reference voltage, plus or minus the input offset voltage. External positive feedback circuitry can be employed to increase effective hysteresis if desired as shown in Figure 1. This circuitry will provide an apparent effect on both the rising and falling input thresholds (the actual internal trip points remain unaffected). If an inverting configuration with hysteresis is needed, simply swap the VIN and VREF connections. Unused Inputs Any unused inputs should be connected in a way that fixes the output logic state high or low. One easy way to do this is to tie +IN to V+ and –IN to GND. Input Protection External input protection circuitry is only needed if currents would otherwise exceed the absolute maximum rating. Inputs driven further negative than 100mV below ground will not cause damage provided the current is limited to 10mA. ESD protection diodes are provided to prevent damage during handling. Comparator Input The allowable input voltage ranges from 100mV below GND to within 1.2V of the positive supply. The input may be forced below ground without causing an improper output, though some additional input current will begin to flow from the ESD input protection diode. The inputs can reach up to 6V independent of the V+ supply voltage without causing additional input current or damage to the part. As long as one input is within the allowable input voltage range, the LTC6702 will continue to function normally. Comparator Output The comparator output is a push-pull CMOS stage guaranteed to swing to within 350mV of V + and 250mV of ground, over temperature when sourcing or sinking 15mA. No external pull-up/down resistor is required. To Additional Hystersis = R1 + •V R3 Trip Voltages: 1 1 1 + VIN(LH) = VREF • R1 • + R1 R2 R3 R3 VIN 1 R1 1 1 VIN(HL) = VREF • R1 • + + • V+ R1 R2 R3 R3 + R1 1/2 LTC6702 R2 VREF – 6702 F01 Example: Additional Hysteresis = 50mV, V + = 5V R1= 10k R2 = 249k R3 = 1M FOR VREF = 0.5V : V IN (L H) = 0.525V V IN (HL) = 0.475V Figure 1. Additional Hysteresis Circuit for Noninverting Configuration 6702f 7 LTC6702 APPLICATIONS INFORMATION maintain micropower operation, the output stage uses a break-before-make circuit. The break interval of this circuit turns off both the pull-up and pull-down devices for tens of nanoseconds before activating the appropriate output transistor (depends on the output transition direction). Any load connected to the output will charge or discharge internal capacitance during this interval. This can create a soft corner during output transitions and also decrease the propagation delay. The Typical Performance Characteristics section shows this behavior under three load conditions: unloaded, 10k to ground and 200Ω to ground. Loads to V+ have a similar affect when the output is transitioning from low to high. Power Supplies at least 1mA, a 1μF bypass capacitor is recommended. Pulsing the V+ supply to the comparators on and off may engage the ESD protection circuitry at the V+ pin. If this occurs, current is pulled from the V+ pin through the output stage. Using the recommended supply bypass capacitors with some series resistance in the V+ supply line will help to prevent this action in pulsed supply applications. Level Translators The level translators in the Typical Applications section show an adjustable high-precision voltage reference enabling the user to vary the threshold voltage. Simply adjusting the ratio of the two resistors changes the threshold voltage according to the following equation: R VTHR = 0.4 1+ F RG The comparator circuitry operates from a single 1.7V to 5.5V. A 0.1μF minimum bypass capacitor is required between the V+ pin and GND. When the output is sinking TYPICAL APPLICATIONS Low to High Level Translator 5.5V LT6650 OUT IN 0.1μF 500mV – 24.9k GND 1μF FB 100k 2V 0V 1/2 LTC6702 OUT 5.5V 0V + 6702 TA02 6702f 8 LTC6702 TYPICAL APPLICATIONS High to Low Level Translator 1.8V LT6650 OUT IN 500mV GND 0.1μF – 24.9k 1μF FB OUT 1/2 LTC6702 6V 0V 1.8V 0V + 100k 6702 TA03 Micropower Battery Monitor with Fast Response VBATT R1 909k LTC6702 + LT1790-1.25 IN C1 0.1μF 0.1μF GND COMPB OUTB (0V IF VBATT < 2.1V) COMPA OUTA (0V IF VBATT < 2.8V) – OUT 1μF R2 332k – + R3 1M 6702 TA04 6702f 9 LTC6702 PACKAGE DESCRIPTION DC Package 8-Lead Plastic DFN (2mm × 2mm) (Reference LTC DWG # 05-08-1719 Rev Ø) 0.70 ±0.05 2.55 ±0.05 1.15 ±0.05 0.64 ±0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ± 0.05 0.45 BSC 1.37 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED R = 0.05 TYP 2.00 ±0.10 (4 SIDES) PIN 1 BAR TOP MARK (SEE NOTE 6) R = 0.115 TYP 5 8 0.40 ± 0.10 0.64 ± 0.10 (2 SIDES) PIN 1 NOTCH R = 0.20 OR 0.25 × 45° CHAMFER (DC8) DFN 0106 REVØ 4 0.200 REF 1 0.23 ± 0.05 0.45 BSC 0.75 ±0.05 1.37 ±0.10 (2 SIDES) 0.00 – 0.05 BOTTOM VIEW—EXPOSED PAD NOTE: 1. DRAWING IS NOT A JEDEC PACKAGE OUTLINE 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 6702f 10 LTC6702 PACKAGE DESCRIPTION TS8 Package 8-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1637) 0.52 MAX 2.90 BSC (NOTE 4) 0.65 REF 1.22 REF 1.4 MIN 3.85 MAX 2.62 REF 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE ID RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.22 – 0.36 8 PLCS (NOTE 3) 0.65 BSC 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF 0.09 – 0.20 (NOTE 3) 1.95 BSC NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. JEDEC PACKAGE REFERENCE IS MO-193 TS8 TSOT-23 0802 6702f Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 11 LTC6702 TYPICAL APPLICATION Dual Low Side Current Sense Alarm 5.5V LED B V+ LTC6702 1k – LOAD B ILOADB LT6650 RSB 0.17 IN 0.1MF GND FB OUT COMP B 500mV 1MF + 24.9k LED A 1k 37.4k + 61.9k COMP A – LOAD A ILOADA GND RSA 0.17 6702 TA05 LEDA ON IF ILOADA > 2.5A LEDB ON IF ILOADB > 5.0A RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1441/LTC1442 Dual Ultralow Power Comparators with Reference 1.182V ±1% Reference, 8μs Propagation Delay, 5.7μA LTC1541/LTC1542 Micropower Amplifier with Comparator and Reference 1.2V ±0.8% Reference, Amplifier Stable with 1000pF Load LTC1842/LTC1843 Dual Ultralow Power Comparators with Reference 1.182V ±1% Reference, 4μs, 3.5μA, Open-Drain Out LT6660 Tiny Micropower Precision Series References 0.2% Reference, 20ppm/°C Drift, 20mA Output, 2mm × 2mm DFN Package LT6700-1/LT6700-2/ LT6700-3 Dual Comparators with 400mV Reference 1.4V to 18V Operating Range, 18μs Propagation Delay, SOT-23 Package LT6703-2/LT6703-3 Tiny Single Comparator with 400mV Reference 1.4V to 18V Operating Range, 18μs Propagation Delay, 2mm × 2mm DFN Package 6702f 12 Linear Technology Corporation LT 0907 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2007