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19-1862; Rev 2; 8/02
SC70, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference
General Description
The MAX9117-MAX9120 nanopower comparators in space-saving SC70 packages feature Beyond-theRailsTM inputs and are guaranteed to operate down to +1.8V. The MAX9117/MAX9118 feature an on-board 1.252V 1.75% reference and draw an ultra-low supply current of only 600nA, while the MAX9119/MAX9120 (without reference) require just 350nA of supply current. These features make the MAX9117-MAX9120 family of comparators ideal for all 2-cell battery-monitoring/management applications. The unique design of the output stage limits supply-current surges while switching, virtually eliminating the supply glitches typical of many other comparators. This design also minimizes overall power consumption under dynamic conditions. The MAX9117/MAX9119 have a push-pull output stage that sinks and sources current. Large internal-output drivers allow Rail-to-Rail(R) output swing with loads up to 5mA. The MAX9118/MAX9120 have an open-drain output stage that makes them suitable for mixed-voltage system design. All devices are available in the ultra-small 5-pin SC70 package.
Features
o Space-Saving SC70 Package (Half the Size of SOT23) o Ultra-Low Supply Current 350nA Per Comparator (MAX9119/MAX9120) 600nA Per Comparator with Reference (MAX9117/MAX9118) o Guaranteed to Operate Down to +1.8V o Internal 1.252V 1.75% Reference (MAX9117/MAX9118) o Input Voltage Range Extends 200mV Beyond-the-Rails o CMOS Push-Pull Output with 5mA Drive Capability (MAX9117/MAX9119) o Open-Drain Output Versions Available (MAX9118/MAX9120) o Crowbar-Current-Free Switching o Internal Hysteresis for Clean Switching o No Phase Reversal for Overdriven Inputs
MAX9117-MAX9120
Applications
2-Cell Battery Monitoring/Management Ultra-Low-Power Systems Mobile Communications Notebooks and PDAs Threshold Detectors/Discriminators Sensing at Ground or Supply Line Telemetry and Remote Systems Medical Instruments
Ordering Information
PART MAX9117EXK-T MAX9118EXK-T MAX9119EXK-T MAX9120EXK-T TEMP RANGE -40C to +85C -40C to +85C -40C to +85C -40C to +85C PINPACKAGE 5 SC70-5 5 SC70-5 5 SC70-5 5 SC70-5 TOP MARK ABW ABX ABY ABZ
Selector Guide
PART MAX9117 MAX9118 MAX9119 MAX9120 INTERNAL REFERENCE Yes Yes No No OUTPUT TYPE Push-Pull Open-Drain Push-Pull Open-Drain SUPPLY CURRENT (nA) 600 600 350 350
IN+ 3 VEE 2
Pin Configurations
TOP VIEW
OUT 1 5 VCC
MAX9117 MAX9118 MAX9119 MAX9120
4 IN- (REF)
Typical Application Circuit appears at end of data sheet. Beyond-the-Rails is a trademark of Maxim Integrated Products, Inc. Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
SC70
( ) ARE FOR MAX9117/MAX9118.
________________________________________________________________ Maxim Integrated Products
1
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.
SC70, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference MAX9117-MAX9120
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VCC to VEE)..................................................+6V Voltage Inputs (IN+, IN-, REF) .........(VEE - 0.3V) to (VCC + 0.3V) Output Voltage MAX9117/MAX9119 ....................(VEE - 0.3V) to (VCC + 0.3V) MAX9118/MAX9120 ..................................(VEE - 0.3V) to +6V Current Into Input Pins ........................................................20mA Output Current..................................................................50mA Output Short-Circuit Duration .................................................10s Continuous Power Dissipation (TA = +70C) 5-Pin SC70 (derate 2.5mW/C above +70C) .............200mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
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--MAX9117/MAX9118
(VCC = +5V, VEE = 0V, VIN+ = VREF, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1)
PARAMETER Supply Voltage Range Supply Current SYMBOL VCC ICC VCC = 1.8V VCC = 5V TA = +25C TA = TMIN to TMAX VEE 0.2 1 4 0.15 0.1 TA = +25C TA = TMIN to TMAX TA = +25C TA = TMIN to TMAX TA = +25C TA = TMIN to TMAX TA = +25C TA = TMIN to TMAX 0.002 VCC = 5V VCC = 1.8V VCC = 5V VCC = 1.8V 35 3 35 3 16 14 s mA 100 190 100 190 1 2 1 400 500 200 300 400 500 200 300 1 mA mV mV CONDITIONS Inferred from the PSRR test MIN 1.8 0.60 0.68 1.30 VCC + 0.2 5 10 V mV mV nA mV/V A TYP MAX 5.5 UNITS V
IN+ Voltage Range Input Offset Voltage Input-Referred Hysteresis Input Bias Current Power-Supply Rejection Ratio
VIN+ VOS VHB IB PSRR VCC VOH
Inferred from output swing test (Note 2) (Note 3) TA = +25C TA = TMIN to TMAX VCC = 1.8V to 5.5V MAX9117, VCC = 5V, ISOURCE = 5mA MAX9117, VCC = 1.8V, ISOURCE = 1mA VCC = 5V, ISINK= 5mA TA = +25C TA = TMIN to TMAX
Output Voltage Swing High
Output Voltage Swing Low
VOL VCC = 1.8V, ISINK= 1mA
Output Leakage Current
ILEAK
MAX9118 only, VO = 5.5V Sourcing, VO = VEE
Output Short-Circuit Current
ISC Sinking, VO = VCC
High-to-Low Propagation Delay (Note 4)
tPD-
VCC = 1.8V VCC = 5V
2
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SC70, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference
ELECTRICAL CHARACTERISTICS--MAX9117/MAX9118 (continued)
(VCC = +5V, VEE = 0V, VIN+ = VREF, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1)
PARAMETER SYMBOL MAX9117 only Low-to-High Propagation Delay (Note 4) tPD+ MAX9118 only CONDITIONS VCC = 1.8V VCC = 5V VCC = 1.8V, RPULLUP = 100k VCC = 5V, RPULLUP = 100k Rise Time Fall Time Power-Up Time Reference Voltage Reference Voltage Temperature Coefficient Reference Output Voltage Noise Reference Line Regulation Reference Load Regulation tRISE tFALL tON VREF TCREF EN VREF/ VCC VREF/ IOUT BW = 10Hz to 100kHz BW = 10Hz to 100kHz, CREF = 1nF VCC = 1.8V to 5.5V IOUT = 10nA TA = +25C TA = TMIN to TMAX 1.230 1.196 100 1.1 0.2 0.25 1 MAX9117 only, CL = 15pF CL = 15pF MIN TYP 15 40 16 45 1.6 0.2 1.2 1.252 1.274 1.308 s s ms V ppm/ C mVRMS mV/V mV/ nA s MAX UNITS
MAX9117-MAX9120
ELECTRICAL CHARACTERISTICS--MAX9119/MAX9120
(VCC = +5V, VEE = 0V, VCM = 0V, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1)
PARAMETER Supply Voltage Range Supply Current Input Common-Mode Voltage Range Input Offset Voltage Input-Referred Hysteresis Input Bias Current Input Offset Current Power-Supply Rejection Ratio Common-Mode Rejection Ratio SYMBOL VCC ICC VCC = 1.8V VCC = 5V TA = +25C TA = TMIN to TMAX VEE 0.2 1 CONDITIONS Inferred from the PSRR test MIN 1.8 0.35 0.45 0.80 1.2 VCC + 0.2 5 mV TA = TMIN to TMAX 4 0.15 75 VCC = 1.8V to 5.5V (VEE - 0.2V) VCM (VCC + 0.2V) 0.1 0.5 1 3 1 2 10 mV nA pA mV/V mV/V V A TYP MAX 5.5 UNITS V
VCM
Inferred from the CMRR test -0.2V VCM (VCC + 0.2V) (Note 2) TA = +25C
VOS VHB IB IOS PSRR CMRR
-0.2V VCM (VCC + 0.2V) (Note 3) TA = +25C TA = TMIN to TMAX
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SC70, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference MAX9117-MAX9120
ELECTRICAL CHARACTERISTICS--MAX9119/MAX9120 (continued)
(VCC = +5V, VEE = 0V, VCM = 0V, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 1)
PARAMETER SYMBOL VCC VOH CONDITIONS MAX9119 only, VCC = 5V, ISOURCE = 5mA MAX9120 only, VCC = 1.8V, ISOURCE = 1mA VCC = 5V, ISINK = 5mA VCC = 1.8V, ISINK = 1mA TA = +25C TA = TMIN to TMAX TA = +25C TA = TMIN to TMAX TA = +25C TA = TMIN to TMAX TA = +25C TA = TMIN to TMAX 0.001 35 3 35 3 16 14 15 40 16 45 1.6 0.2 1.2 s s ms s s mA VCC = 5V VCC = 1.8V VCC = 5V VCC = 1.8V VCC = 1.8V VCC = 5V MAX9119 only Low-to-High Propagation Delay (Note 4) tPD+ MAX9120 only VCC = 1.8V VCC = 5V VCC = 1.8V, RPULLUP = 100k VCC = 5V, RPULLUP = 100k Rise Time Fall Time Power-Up Time tRISE tFALL tON MAX9119 only, CL = 15pF CL = 15pF 100 190 100 MIN TYP 190 MAX 400 500 200 300 400 500 200 300 1 A mV mV UNITS
Output Voltage Swing High
Output Voltage Swing Low
VOL
Output Leakage Current
ILEAK
MAX9120 only, VO = 5.5V Sourcing, VO = VEE
Output Short-Circuit Current
ISC Sourcing, VO = VCC
High-to-Low Propagation Delay (Note 4)
tPD-
Note 1: All specifications are 100% tested at TA = +25C. Specification limits over temperature (TA = TMIN to TMAX) are guaranteed by design, not production tested. Note 2: VOS is defined as the center of the hysteresis band at the input. Note 3: The hysteresis-related trip points are defined as the edges of the hysteresis band, measured with respect to the center of the band (i.e., VOS) (Figure 2). Note 4: Specified with an input overdrive (VOVERDRIVE) of 100mV, and load capacitance of CL = 15pF. VOVERDRIVE is defined above and beyond the offset voltage and hysteresis of the comparator input. For the MAX9117/MAX9118, reference voltage error should also be added.
4
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SC70, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference MAX9117-MAX9120
Typical Operating Characteristics
(VCC = +5V, VEE = 0V, CL = 15pF, VOVERDRIVE = 100mV, TA = +25C, unless otherwise noted.)
MAX9117/MAX9118 SUPPLY CURRENT vs. SUPPLY VOLTAGE AND TEMPERATURE
MAX9117-20 toc01
MAX9119/MAX9120 SUPPLY CURRENT vs. SUPPLY VOLTAGE AND TEMPERATURE
MAX9117-20 toc02
MAX9117/MAX9118 SUPPLY CURRENT vs. TEMPERATURE
MAX9117-20 toc03
950 900 SUPPLY CURRENT (nA) 850 800 750 700 650 600 550 500 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 TA = -40C TA = +25C TA = +85C
550 500 SUPPLY CURRENT (nA) TA = +85C 450 400 350 TA = -40C 300 250 TA = +25C
900 850 SUPPLY CURRENT (nA) 800 750 VCC = +3V 700 650 VCC = +1.8V 600 550 VCC = +5V
5.5
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
-40
-15
10
35
60
85
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
TEMPERATURE (C)
MAX9119/MAX9120 SUPPLY CURRENT vs. TEMPERATURE
MAX9117-20 toc04
MAX9117/MAX9118 SUPPLY CURRENT vs. OUTPUT TRANSITION FREQUENCY
MAX9117-20 toc05
MAX9119/MAX9120 SUPPLY CURRENT vs. OUTPUT TRANSITION FREQUENCY
30 SUPPLY CURRENT (A) 25 20 VCC = +5V 15 10 5 0 VCC = +3V VCC = +1.8V
MAX9117-20 toc06
550 500 SUPPLY CURRENT (nA) 450 400 350 300 VCC = +1.8V 250 -40 -15 10 35 60 VCC = +5V VCC = +3V
35 30 SUPPLY CURRENT (A) 25 20 VCC = +5V 15 10 5 0 VCC = +3V VCC = +1.8V
35
85
1
10
100
1k
10k
100k
1
10
100
1k
10k
100k
TEMPERATURE (C)
OUTPUT TRANSITION FREQUENCY (Hz)
OUTPUT TRANSITION FREQUENCY (Hz)
OUTPUT VOLTAGE LOW vs. SINK CURRENT
MAX9117-20 toc07
OUTPUT VOLTAGE LOW vs. SINK CURRENT AND TEMPERATURE
MAX9117-20 toc08
MAX9117/MAX9119 OUTPUT VOLTAGE HIGH vs. SOURCE CURRENT
MAX9117-20 toc09
700 600 VCC = +3V 500 VOL (mV) 400 300 200 100 0 0 1 2 3 4 5 6 7 8 9 VCC = +5V VCC = +1.8V
600 500 400 VOL (mV) 300 200 TA = +85C TA = +25C
0.7 0.6 0.5 VCC - VOH (V) 0.4 0.3 0.2 VCC = +1.8V VCC = +3V
100 0 10 0 1 2 3 4 5 6
VCC = +5V
TA = -40C 7 8 9 10
0.1 0 0 1 2 3 4 5 6 7 8 9 10
SINK CURRENT (mA)
SINK CURRENT (mA)
SOURCE CURRENT (mA)
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SC70, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference MAX9117-MAX9120
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = 0V, CL = 15pF, VOVERDRIVE = 100mV, TA = +25C, unless otherwise noted.)
MAX9117/MAX9119 OUTPUT VOLTAGE HIGH vs. SOURCE CURRENT AND TEMPERATURE
MAX9117-20 toc10
SHORT-CIRCUIT SINK CURRENT vs. TEMPERATURE
MAX9117-20 toc11
MAX9117/MAX9119 SHORT-CIRCUIT SOURCE CURRENT vs. TEMPERATURE
45 40 SOURCE CURRENT (mA) 35 30 25 20 15 10 VCC = +3V VCC = +5V
MAX9117-20 toc12
0.6 0.5 0.4 0.3 TA = +85C 0.2 0.1 0 0 1 2 3 4 5 6 7 8 9 TA = -40C TA = +25C
40 35 VCC = +5V SINK CURRENT (mA) 30 25 20 15 10 5 0 VCC = +1.8V -40 -15 10 35 60 VCC = +3V
50
VCC - VOH (V)
5 0 85 -40
VCC = +1.8V -15 10 35 60 85
10
SOURCE CURRENT (mA)
TEMPERATURE (C)
TEMPERATURE (C)
OFFSET VOLTAGE vs. TEMPERATURE
MAX9117-20 toc13
HYSTERESIS VOLTAGE vs. TEMPERATURE
MAX9117-20 toc14
MAX9117/MAX9118 REFERENCE VOLTAGE vs. TEMPERATURE
1.258 1.256 REFERENCE VOLTAGE (V) 1.254 1.252 1.250 1.248 1.246 1.244 1.242 VCC = +3V VCC = +1.8V VCC = +5V
MAX9117-20 toc15
1.2 1.1 1.0 0.9 VOS (mV) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 -40 -15 10 35 60 VCC = +5V VCC = +1.8V VCC = +3V
6.0 5.5 5.0 VHB (mV) 4.5 4.0 3.5 3.0 -40
1.260
85
-15
10
35
60
85
1.240 -40
-15
10
35
60
85
TEMPERATURE (C)
TEMPERATURE (C)
TEMPERATURE (C)
MAX9117/MAX9118 REFERENCE VOLTAGE vs. SUPPLY VOLTAGE
MAX9117-20 toc16
MAX9117/MAX9118 REFERENCE OUTPUT VOLTAGE vs. REFERENCE SOURCE CURRENT
MAX9117-20 toc17
MAX9117/MAX9118 REFERENCE OUTPUT VOLTAGE vs. REFERENCE SINK CURRENT
1.258 1.256 REFERENCE VOLTAGE (V) 1.254 1.252 1.250 1.248 1.246 1.244 1.242 1.240 VCC = +3V VCC = +1.8V VCC = +5V
MAX9117-20 toc18
1.254
1.260 1.258 REFERENCE VOLTAGE (V) 1.256 1.254 1.252 1.250 1.248 1.246 1.244 1.242 VCC = +1.8V, +3V VCC = +5V
1.260
REFERENCE VOLTAGE (V)
1.253
1.252
1.251
1.250
1.249 1.5
1.240 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 0 1 2 3 4 5 6 7 8 9 10 SUPPLY VOLTAGE (V) SOURCE CURRENT (nA)
0
1
2
3
4
5
6
7
8
9
10
SINK CURRENT (nA)
6
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SC70, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = 0V, CL = 15pF, VOVERDRIVE = 100mV, TA = +25C, unless otherwise noted.)
PROPAGATION DELAY (tPD-) vs. TEMPERATURE
MAX9117-20 toc19
MAX9117-MAX9120
MAX9117/MAX9119 PROPAGATION DELAY (tPD+) vs. TEMPERATURE
MAX9117-20 toc20
PROPAGATION DELAY (tPD-) vs. CAPACITIVE LOAD
180 160 140 tPD- (s) 120 100 80 60 VCC = +5V VCC = +3V VCC = +1.8V
MAX9117-20 toc21
28 26 24 22 tPD- (s)
60 50 40 tPD+ (s) 30 VCC = +3V 20 VCC = +5V
200
20 18 16 14 12 10 8 -40 -15
VCC = +1.8V
VCC = +3V VCC = +5V 10 35 60 85
10 0 -40 -15 10
VCC = +1.8V
40 20 60 85 0 0.01 0.1 1 10 100 1000
35
TEMPERATURE (C)
TEMPERATURE (C)
CAPACITIVE LOAD (nF)
MAX9117/MAX9119 PROPAGATION DELAY (tPD+) vs. CAPACITIVE LOAD
MAX9117-20 toc22
PROPAGATION DELAY (tPD-) vs. INPUT OVERDRIVE
MAX9117-20 toc23
MAX9117/MAX9119 PROPAGATION DELAY (tPD+) vs. INPUT OVERDRIVE
35 30 tPD+ (s) 25 20 15 10 VCC = +1.8V VCC = +3V VCC = +5V
MAX9117-20 toc24
180 160 140 120 tPD+ (s) VCC = +1.8V
80 70 60 tPD- (s) 50 VCC = +1.8V 40 VCC = +5V 30 20 10 VCC = +3V 0 10 20 30 40
40
100 80 60 40 20 0 0.01 0.1 1 10 100 1000 VCC = +5V VCC = +3V
5 0 50 0 10 20 30 40 50
CAPACITIVE LOAD (nF)
INPUT OVERDRIVE (mV)
INPUT OVERDRIVE (mV)
MAX9118/MAX9120 PROPAGATION DELAY (tPD-) vs. PULLUP RESISTANCE
MAX9117-20 toc25
MAX9118/MAX9120 PROPAGATION DELAY (tPD+) vs. PULLUP RESISTANCE
MAX9117-20 toc26
PROPAGATION DELAY (tPD-) (VCC = +5V)
15 14 13 tPD- (s) VCC = +1.8V
100
MAX9117-20 toc27
80
IN+ (50mV/div) OV
tPD+ (s)
60 VCC = +5V 40 VCC = +3V 20
12 11 10
VCC = +3V
OUT (2V/div) VCC = +1.8V OV 10,000
VCC = +5V 9 10 100 1000 10,000 RPULLUP (k) 0 10 100
1000
20s/div
RPULLUP (k)
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SC70, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference MAX9117-MAX9120
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = 0V, CL = 15pF, VOVERDRIVE = 100mV, TA = +25C, unless otherwise noted.)
MAX9117/MAX9119 PROPAGATION DELAY (tPD+) (VCC = +5V)
MAX9117-20 toc28
PROPAGATION DELAY (tPD-) (VCC = +3V)
MAX9117-20 toc29
MAX9117/MAX9119 PROPAGATION DELAY (tPD+) (VCC = +3V)
MAX9117-20 toc30
IN+ (50mV/div) OV
IN+ (50mV/div) OV
IN+ (50mV/div) OV
OUT (2V/div) OV 20s/div
OUT (2V/div) OV
OUT (2V/div) OV
20s/div
20s/div
PROPAGATION DELAY (tPD-) (VCC = +1.8V)
MAX9117-20 toc31
MAX9117/MAX9119 PROPAGATION DELAY (tPD+) (VCC = +1.8V)
MAX9117-20 toc32
MAX9117/MAX9119 10kHz RESPONSE (VCC = +1.8V)
MAX9117-20 toc33
IN+ (50mV/div) OV
IN+ (50mV/div) OV
IN+ (50mV/div) OV
OUT (1V/div) OV
OUT (1V/div) OV
OUT (1V/div) OV 20s/div
20s/div
20s/div
MAX9117/MAX9119 1kHz RESPONSE (VCC = +5V)
POWER-UP/DOWN RESPONSE
MAX9117-20 toc35
MAX9117-20 toc34
IN+ (50mV/div) OV
VCC (2V/div) OV
OUT (2V/div) OUT (2V/div) OV 200s/div 40s/div OV
8
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SC70, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference
Functional Diagrams
MAX9117-MAX9120
VCC
VCC
IN+ OUT REF
IN+ OUT IN-
MAX9117 MAX9118
REF 1.252V VEE VEE
MAX9119 MAX9120
Pin Description
PIN MAX9117/ MAX 9118 1 2 3 4 5 MAX9119/ MAX 9120 1 2 3 -- 5 4 NAME OUT VEE IN+ REF VCC INFUNCTION Comparator Output Negative Supply Voltage Comparator Noninverting Input 1.252V Reference Output Positive Supply Voltage Comparator Inverting Input
mum of 6V above VEE. These open-drain versions are ideal for implementing wire-OR output logic functions.
Input Stage Circuitry
The input common-mode voltage range extends from VEE - 0.2V to VCC + 0.2V. These comparators operate at any differential input voltage within these limits. Input bias current is typically 0.15nA if the input voltage is between the supply rails. Comparator inputs are protected from overvoltage by internal ESD protection diodes connected to the supply rails. As the input voltage exceeds the supply rails, these ESD protection diodes become forward biased and begin to conduct.
Output Stage Circuitry
The MAX9117-MAX9120 contain a unique breakbefore-make output stage capable of rail-to-rail operation with up to 5mA loads. Many comparators consume orders of magnitude more current during switching than during steady-state operation. However, with this family of comparators, the supply-current change during an output transition is extremely small. In the Typical Operating Characteristics, the Supply Current vs. Output Transition Frequency graphs show the minimal supply-current increase as the output switching frequency approaches 1kHz. This characteristic reduces the need for power-supply filter capacitors to reduce glitches created by comparator switching currents. In battery-powered applications, this characteristic results in a substantial increase in battery life.
Detailed Description
The MAX9117/MAX9118 feature an on-board 1.252V 1.75% reference, yet draw an ultra-low supply current of 600nA. The MAX9119/MAX9120 (without reference) consume just 350nA of supply current. All four devices are guaranteed to operate down to +1.8V. Their common-mode input voltage range extends 200mV beyond-the-rails. Internal hysteresis ensures clean output switching, even with slow-moving input signals. Large internal output drivers allow rail-to-rail output swing with up to 5mA loads. The output stage employs a unique design that minimizes supply-current surges while switching, virtually eliminating the supply glitches typical of many other comparators. The MAX9117/MAX9119 have a push-pull output stage that sinks as well as sources current. The MAX9118/MAX9120 have an open-drain output stage that can be pulled beyond VCC to an absolute maxi-
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SC70, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference MAX9117-MAX9120
Reference (MAX9117/MAX9118)
The internal reference in the MAX9117/MAX9118 has an output voltage of +1.252V with respect to VEE. Its typical temperature coefficient is 100ppm/C over the full -40C to +85C temperature range. The reference is a PNP emitter-follower driven by a 120nA current source (Figure 1). The output impedance of the voltage reference is typically 200k, preventing the reference from driving large loads. The reference can be bypassed with a low-leakage capacitor. The reference is stable for any capacitive load. For applications requiring a lower output impedance, buffer the reference with a low-input-leakage op amp, such as the MAX4162.
VCC
120nA REF
VBIAS VEE
Applications Information
Low-Voltage, Low-Power Operation
The MAX9117-MAX9120 are ideally suited for use with most battery-powered systems. Table 1 lists a variety of battery types, capacities, and approximate operating times for the MAX9117-MAX9120, assuming nominal conditions.
Figure 1. MAX9117/MAX9118 Voltage Reference Output Equivalent Circuit
region where oscillation occurs. Figure 2 illustrates the case in which IN- has a fixed voltage applied, and IN+ is varied. If the inputs were reversed, the figure would be the same, except with an inverted output.
Internal Hysteresis
Many comparators oscillate in the linear region of operation because of noise or undesired parasitic feedback. This tends to occur when the voltage on one input is equal or very close to the voltage on the other input. The MAX9117-MAX9120 have internal hysteresis to counter parasitic effects and noise. The hysteresis in a comparator creates two trip points: one for the rising input voltage (VTHR) and one for the falling input voltage (VTHF) (Figure 2). The difference between the trip points is the hysteresis (VHB). When the comparator's input voltages are equal, the hysteresis effectively causes one comparator input to move quickly past the other, thus taking the input out of the
Additional Hysteresis (MAX9117/MAX9119)
The MAX9117/MAX9119 have a 4mV internal hysteresis band (VHB). Additional hysteresis can be generated with three resistors using positive feedback (Figure 3). Unfortunately, this method also slows hysteresis response time. Use the following procedure to calculate resistor values. 1) Select R3. Leakage current at IN is under 2nA, so the current through R3 should be at least 0.2A to minimize errors caused by leakage current. The current through R3 at the trip point is (VREF - VOUT) / R3. Considering the two possible output states in solving for R3 yields two formulas: R3 = VREF / IR3 or R3 = (VCC - VREF) / IR3. Use the smaller of the two resulting resistor values. For example, when using the
Table 1. Battery Applications Using MAX9117-MAX9120
BATTERY TYPE Alkaline (2 Cells) Nickel-Cadmium (2 Cells) Lithium-Ion (1 Cell) Nickel-MetalHydride (2 Cells) 10 RECHARGEABLE VFRESH (V) 3.0 2.4 3.5 VEND-OF-LIFE (V) 1.8 1.8 2.7 CAPACITY, AA SIZE (mA-h) 2000 750 1000 MAX9117/MAX9118 OPERATING TIME (hr) 2.5 x 106 937,500 1.25 x 106 MAX9119/MAX9120 OPERATING TIME (hr) 5 x 106 1.875 x 106 2.5 x 106
No Yes Yes
Yes
2.4
1.8
1000
1.25 x 106
2.5 x 106
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SC70, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference MAX9117-MAX9120
IN+ VTHR R1 INVHB VTHF HYSTERESIS BAND R2 VEE VIN VCC OUT THRESHOLDS VCC R3
VREF OUT
MAX9117 MAX9119
Figure 2. Threshold Hysteresis Band
Figure 3. MAX9117/MAX9119 Additional Hysteresis
MAX9117 (VREF = 1.252V) and VCC = +5V, and if we choose IR3 = 1A, then the two resistor values are 1.2M and 3.8M. Choose a 1.2M standard value for R3. 2) Choose the hysteresis band required (VHB). For this example, choose 50mV. 3) Calculate R1 according to the following equation: R1 = R3 (VHB / VCC) For this example, insert the values: R1 = 1.2M (50mV / 5V) = 12k 4) Choose the trip point for VIN rising (VTHR) such that VTHR > VREF (R1 + R3) / R3, (VTHF is the trip point for VIN falling). This is the threshold voltage at which the comparator switches its output from low to high as VIN rises above the trip point. For this example, choose 3V. 5) Calculate R2 as follows: R2 = 1 / [VTHR / (VREF R1) - (1 / R1) - (1 / R3)] R2 = 1 / [3.0V / (1.2V 12k) - (1 / 12k) (1 / 1.2M)] = 8.05k For this example, choose an 8.2k standard value. 6) Verify the trip voltages and hysteresis as follows: VIN rising: VTHR = VREF R1 [(1 / R1) + (1 / R2) + (1 / R3)] VIN falling: VTHF = VTHR - (R1 VCC / R3) Hysteresis = VTHR - VTHF
external pullup resistor (Figure 4). Additional hysteresis can be generated using positive feedback, but the formulas differ slightly from those of the MAX9117/ MAX9119. Use the following procedure to calculate resistor values. 1) Select R3 according to the formulas R3 = VREF / 1A or R3 = (VCC - VREF) / 1A - R4. Use the smaller of the two resulting resistor values. 2) Choose the hysteresis band required (VHB). 3) Calculate R1 according to the following equation: R1 = (R3 + R4) (VHB / VCC) 4) Choose the trip point for VIN rising (VTHR) (VTHF is the trip point for VIN falling). This is the threshold voltage at which the comparator switches its output from low to high as VIN rises above the trip point. 5) Calculate R2 as follows: 1 1 R2 = 1 VTHR (VREF x R1) - - R1 R 3 6) Verify the trip voltages and hysteresis as follows: 1 1 1 VIN risin g : VTHR = VREF x R1 + + R1 R2 R 3 VIN falling : R1 1 1 1 VTHF = VREF x R1 + + x VCC - R1 R2 R 3 + R4 R 3 + R4 Hysteresis = VTHR - VTHF
Additional Hysteresis (MAX9118/MAX9120)
The MAX9118/MAX9120 have a 4mV internal hysteresis band. They have open-drain outputs and require an
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11
SC70, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference MAX9117-MAX9120
Board Layout and Bypassing
Power-supply bypass capacitors are not typically needed, but use 100nF bypass capacitors close to the device's supply pins when supply impedance is high, supply leads are long, or excessive noise is expected on the supply lines. Minimize signal trace lengths to reduce stray capacitance. A ground plane and surface-mount components are recommended. If the REF pin is decoupled, use a new low-leakage capacitor.
Typical Application Circuit
+5V (+3V) +3V (+5V) 2M INOUT 2M IN+ 3V (5V) LOGIC OUT VCC
RPULLUP
Zero-Crossing Detector
Figure 5 shows a zero-crossing detector application. The MAX9119's inverting input is connected to ground, and its noninverting input is connected to a 100mVP-P signal source. As the signal at the noninverting input crosses 0V, the comparator's output changes state.
MAX9120
VEE 5V (3V) LOGIC IN LOGIC-LEVEL TRANSLATOR
Logic-Level Translator
The Typical Application Circuit shows an application that converts 5V logic to 3V logic levels. The MAX9120 is powered by the +5V supply voltage, and the pullup resistor for the MAX9120's open-drain output is connected to the +3V supply voltage. This configuration allows the full 5V logic swing without creating overvoltage on the 3V logic inputs. For 3V to 5V logic-level translations, simply connect the +3V supply voltage to VCC and the +5V supply voltage to the pullup resistor.
VCC R3
Chip Information
TRANSISTOR COUNT: 98
VCC
100mVP-P R1 VIN VCC R2 VEE OUT INR4 IN+
VCC
OUT
VREF
MAX9118 MAX9120
VEE
MAX9119
Figure 4. MAX9118/MAX9120 Additional Hysteresis
Figure 5. Zero-Crossing Detector
12
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SC70, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference
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, 5L.EPS
MAX9117-MAX9120
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 13 (c) 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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