MAX920EUK-T [MAXIM]
SOT23, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference; SOT23封装， 1.8V ，纳安级功耗，超摆幅比较器，带/不带基准
| 型号： | MAX920EUK-T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | SOT23, 1.8V, Nanopower, Beyond-the-Rails Comparators With/Without Reference |
| 文件： | 总12页 (文件大小：152K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-1512; Rev 0; 7/99
SOT23, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
17–MAX920
General Description
Features
The MAX917–MAX920 nanopower comparators in
space-saving SOT23 packages feature Beyond-the-
Rails™ inputs and are guaranteed to operate down to
+1.8V. The MAX917/MAX918 feature an on-board
1.245V 1.5ꢀ reference and draw an ultra-low supply
current of only 750nA, while the MAX919/MAX920 (with-
out reference) require just 380nA of supply current.
These features make the MAX917–MAX920 family of
comparators ideal for all 2-cell battery applications,
including monitoring/management.
♦ Ultra-Low Supply Current
380nA per Comparator (MAX919/MAX920)
750nA per Comparator with Reference
(MAX917/MAX918)
♦ Guaranteed to Operate Down to +1.8V
♦ Internal 1.245V ±1.5% Reference
(MAX917/MAX918)
♦ Input Voltage Range Extends 200mV
Beyond-the-Rails
The unique design of the output stage limits supply-cur-
rent surges while switching, virtually eliminating the
supply glitches typical of many other comparators. This
design also minimizes overall power consumption
under dynamic conditions. The MAX917/MAX919 have
a push/pull output stage that sinks and sources current.
Large internal output drivers allow Rail-to-Rail® output
swing with loads up to 8mA. The MAX918/MAX920
have an open-drain output stage that makes them suit-
able for mixed-voltage system design.
♦ CMOS Push/Pull Output with ±8mA Drive
Capability (MAX917/MAX919)
♦ Open-Drain Output Versions Available
(MAX918/MAX920)
♦ Crowbar-Current-Free Switching
♦ Internal Hysteresis for Clean Switching
♦ No Phase Reversal for Overdriven Inputs
♦ Space-Saving SOT23 Package
Applications
2-Cell Battery Monitoring/Management
Ordering Information
TEMP.
RANGE
PIN-
SOT
Ultra-Low-Power Systems
Mobile Communications
PART
PACKAGE TOP MARK
MAX917EUK-T -40°C to +85°C 5 SOT23-5
MAX917ESA -40°C to +85°C 8 SO
MAX918EUK-T -40°C to +85°C 5 SOT23-5
MAX918ESA -40°C to +85°C 8 SO
MAX919EUK-T -40°C to +85°C 5 SOT23-5
MAX919ESA -40°C to +85°C 8 SO
MAX920EUK-T -40°C to +85°C 5 SOT23-5
ADIQ
—
Notebooks and PDAs
Threshold Detectors/Discriminators
Sensing at Ground or Supply Line
Telemetry and Remote Systems
Medical Instruments
ADIR
—
ADIS
—
ADIT
—
MAX920ESA
-40°C to +85°C 8 SO
Selector Guide
Pin Configurations
SUPPLY
CURRENT
(nA)
INTERNAL
REFERENCE
OUTPUT
TYPE
TOP VIEW
PART
MAX917
MAX918
MAX919
MAX920
Yes
Yes
No
Push/Pull
Open-Drain
Push/Pull
750
750
380
380
1
2
3
5
4
V
OUT
CC
MAX917
MAX918
MAX919
MAX920
V
EE
No
Open-Drain
IN+
IN- (REF)
Typical Application Circuit appears at end of data sheet.
Beyond-the-Rails is a trademark of Maxim Integrated Products.
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
SOT23-5
( ) ARE FOR MAX917/MAX918.
Pin Configurations continue at end of data sheet.
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
SOT23, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V
to V )..................................................+6V
Continuous Power Dissipation (T = +70°C)
A
CC
EE
Voltage Inputs (IN+, IN-, REF) .........(V - 0.3V) to (V
Output Voltage
+ 0.3V)
5-Pin SOT23 (derate 7.31mW/°C above +70°C).........571mW
8-Pin SO (derate 5.88mW/°C above +70°C)...............471mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10sec) .............................+300°C
EE
CC
MAX917/MAX919........................(V - 0.3V) to (V
+ 0.3V)
EE
CC
MAX918/MAX920......................................(V - 0.3V) to +6V
EE
Output Current.................................................................. 50mA
Output Short-Circuit Duration .............................................10sec
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.
17–MAX920
ELECTRICAL CHARACTERISTICS—MAX917/MAX918
(V
CC
= +5V, V = 0, V
= V
, T = -40°C to +85°C, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)
EE
IN+
REF
A
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Supply Voltage Range
V
CC
Inferred from the PSRR test
1.8
5.5
V
V
= 1.8V
0.75
0.80
CC
1.30
1.60
Supply Current
I
T
T
= +25°C
µA
CC
A
V
CC
= 5V
= T
to T
A
MIN
MAX
IN+ Voltage Range
Input Offset Voltage
Input-Referred Hysteresis
Input Bias Current
V
Inferred from the output swing test
V
EE
- 0.2
V
CC
+ 0.2
5
V
mV
mV
nA
IN+
T
= +25°C
1
A
A
V
(Note 2)
OS
HB
T
= T
to T
10
MIN
MAX
V
(Note 3)
4
T
T
= +25°C
0.15
1
A
I
B
= T
to T
2
A
MIN
MAX
Power-Supply Rejection Ratio
PSRR
V
CC
= 1.8V to 5.5V
0.1
1
mV/V
T
T
T
T
T
T
T
T
= +25°C
190
400
500
200
300
400
500
200
300
1
A
A
A
A
A
A
A
A
MAX917 only, V
=
CC
5V, I
= 8mA
SOURCE
= T
to T
MIN
MAX
MAX
MAX
MAX
Output Voltage Swing High
V
- V
mV
CC
OH
= +25°C
= T to T
55
190
55
MAX917 only, V
=
CC
1.8V, I
= 1mA
SOURCE
MIN
= +25°C
= T to T
V
CC
= 5V,
I
= 8mA
SINK
MIN
Output Voltage Swing Low
Output Leakage Current
Output Short-Circuit Current
V
mV
µA
OL
= +25°C
= T to T
V
CC
= 1.8V,
I
= 1mA
SINK
MIN
I
MAX918 only, V = 5.5V
0.001
95
LEAK
O
V
= 5V
CC
CC
CC
CC
Sourcing, V = V
O
EE
V
V
V
= 1.8V
= 5V
8
I
mA
SC
98
Sinking, V = V
O
CC
= 1.8V
10
2
_______________________________________________________________________________________
SOT23, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
17–MAX920
ELECTRICAL CHARACTERISTICS—MAX917/MAX918 (continued)
(V
CC
= +5V, V = 0, V
= V
, T = -40°C to +85°C, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)
EE
IN+
REF
A
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
17
MAX
UNITS
V
V
= 1.8V
= 5V
CC
High-to-Low Propagation Delay
(Note 4)
t
µs
PD-
22
CC
V
V
= 1.8V
= 5V
30
CC
MAX917 only
95
CC
Low-to-High Propagation Delay
(Note 4)
V
R
= 1.8V,
CC
t
35
µs
PD+
= 100kΩ
PULL-UP
MAX918 only
V
CC
= 5V,
120
R
= 100kΩ
PULL-UP
Rise Time
t
MAX917 only, C = 15pF
6
4
µs
µs
RISE
L
Fall Time
t
C = 15pF
L
FALL
Power-Up Time
t
1.2
1.245
ms
ON
T = +25°C
1.227
1.200
1.263
1.290
A
Reference Voltage
V
V
REF
T = T
to T
MAX
A
MIN
Reference Voltage Temperature
Coefficient
TC
95
ppm/°C
REF
BW = 10Hz to 100kHz
600
215
Reference Output
Voltage Noise
e
n
µV
RMS
BW = 10Hz to 100kHz, C
= 1nF
REF
∆V
∆V
/
/
REF
CC
Reference Line Regulation
Reference Load Regulation
1.8V ≤ V
≤ 5.5V
0.1
0.2
mV/V
CC
∆V
REF
∆I
OUT
= 10nA
mV/nA
∆I
OUT
ELECTRICAL CHARACTERISTICS—MAX919/MAX920
(V
CC
= +5V, V = 0, V
= 0, T = -40°C to +85°C, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)
EE
CM
A
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Supply Voltage Range
Supply Current
V
Inferred from the PSRR test
1.8
5.5
V
CC
V
CC
= 1.8V
0.38
0.45
I
T
T
= +25°C
0.80
1.2
µA
V
CC
A
V
CC
= 5V
= T
to T
A
MIN
MAX
Input Common-Mode
Voltage Range
V
CM
Inferred from the CMRR test
V
- 0.2
V + 0.2
CC
EE
T
T
= +25°C
1
5
A
-0.2V ≤ V
(V + 0.2V) (Note 2)
CC
≤
CM
Input Offset Voltage
Input-Referred Hysteresis
Input Bias Current
V
V
mV
mV
nA
OS
= T
to T
10
A
MIN
MAX
-0.2V ≤ V
≤ (V
+ 0.2V) (Note 3)
4
HB
CM
CC
T
A
T
A
= +25°C
0.15
1
2
I
B
= T
to T
MAX
MIN
_______________________________________________________________________________________
3
SOT23, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
ELECTRICAL CHARACTERISTICS—MAX919/MAX920 (continued)
(V
CC
= +5V, V = 0, V
= 0, T = -40°C to +85°C, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)
EE
CM
A
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
10
MAX
UNITS
pA
Input Offset Current
I
OS
Power-Supply Rejection Ratio
PSRR
V
= 1.8V to 5.5V
0.1
0.5
190
1
mV/V
mV/V
CC
Common-Mode Rejection Ratio
CMRR
(V - 0.2V) ≤ V
≤ (V + 0.2V)
CC
3
EE
CM
T
A
T
A
T
A
T
A
T
A
T
A
T
A
T
A
= +25°C
400
500
200
300
400
500
200
300
1
MAX919 only, V
5V, I
=
CC
= 8mA
SOURCE
= T
to T
MIN
MAX
MAX
MAX
MAX
Output Voltage Swing High,
V
- V
OH
mV
CC
= +25°C
= T to T
55
190
55
MAX919 only, V
1.8V, I
=
CC
= 1mA
SOURCE
MIN
= +25°C
= T to T
V
CC
= 5V,
= 8mA
I
SINK
17–MAX920
MIN
Output Voltage Swing Low
Output Leakage Current
Output Short-Circuit Current
V
OL
mV
µA
= +25°C
= T to T
V
CC
= 1.8V,
= 1mA
I
SINK
MIN
I
MAX920 only, V = 5.5V
0.001
95
8
O
LEAK
V
= 5V
CC
CC
CC
CC
CC
CC
CC
CC
Sourcing, V = V
O
EE
V
V
V
V
V
V
V
= 1.8V
= 5V
I
mA
SC
98
10
17
22
30
95
Sinking, V = V
O
CC
= 1.8V
= 1.8V
= 5V
High-to-Low Propagation Delay
(Note 4)
t
µs
µs
PD-
= 1.8V
= 5V
MAX919 only
MAX920 only
Low-to-High Propagation Delay
(Note 4)
V
CC
= 1.8V
t
35
PD+
R
= 100kΩ
PULL-UP
V
CC
= 5V
120
R
= 100kΩ
PULL-UP
Rise Time
t
MAX919 only, C = 15pF
6
4
µs
µs
RISE
L
Fall Time
t
C = 15pF
L
FALL
Power-Up Time
t
1.2
ms
ON
Note 1: All specifications are 100ꢀ tested at T = +25°C. Specification limits over temperature (T = T
to T ) are guaranteed
MAX
A
A
MIN
by design, not production tested.
Note 2: V is defined as the center of the hysteresis band at the input.
OS
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., V ) (Figure 2).
OS
Note 4: Specified with an input overdrive (V
) of 100mV, and load capacitance of C = 15pF. V
is defined
OVERDRIVE
L
OVERDRIVE
above and beyond the offset voltage and hysteresis of the comparator input. For the MAX917/MAX918, reference voltage
error should also be added.
4
_______________________________________________________________________________________
SOT23, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
17–MAX920
Typical Operating Characteristics
(V
CC
= +5V, V = 0, C = 15pF, V = 100mV, T = +25°C, unless otherwise noted.)
OVERDRIVE A
EE
L
MAX917/MAX918
SUPPLY CURRENT vs.
MAX919/MAX920
SUPPLY CURRENT vs.
MAX917/MAX918
SUPPLY VOLTAGE AND TEMPERATURE
SUPPLY VOLTAGE AND TEMPERATURE
600
SUPPLY CURRENT vs. TEMPERATURE
900
850
800
750
700
650
600
550
500
900
800
700
600
500
T
= +85°C
= +25°C
= -40°C
A
V
CC
= 5V
T
T
= +85°C
= +25°C
A
A
500
400
300
T
A
V
CC
= 3V
V
CC
= 1.8V
T
A
T
A
= -40°C
-40
-15
10
35
60
85
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
SUPPLY VOLTAGE (V)
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
MAX919/MAX920
SUPPLY CURRENT vs.
OUTPUT TRANSITION FREQUENCY
MAX917/MAX918
SUPPLY CURRENT vs.
OUTPUT TRANSITION FREQUENCY
MAX919/MAX920
SUPPLY CURRENT vs. TEMPERATURE
550
500
450
400
350
300
14
12
10
8
16
14
V
= 5V
V
= 5V
CC
CC
12
10
8
V
= 5V
= 3V
CC
V
= 3V
CC
V
CC
6
V
= 3V
CC
V
= 1.8V
CC
6
4
4
2
2
V
= 1.8V
CC
V
= 1.8V
CC
0
0
-40
-15
10
35
60
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
AND TEMPERATURE
MAX917/MAX919
OUTPUT VOLTAGE HIGH vs. SOURCE CURRENT
OUTPUT VOLTAGE LOW vs. SINK CURRENT
450
400
350
300
250
200
150
100
50
600
500
0.6
0.5
0.4
0.3
0.2
0.1
0
V
= 1.8V
CC
V
CC
= 1.8V
V
= 3V
CC
V
= 5V
CC
V
= 3V
CC
V
CC
= 5V
400
300
200
100
0
T
= +25°C
A
T
= +85°C
A
T
A
= -40°C
0
0
2
4
6
8
10 12 14 16
0
2
4
6
8
10 12 14 16
0
2
4
6
8
10 12 14 16 18 20
SINK CURRENT (mA)
SINK CURRENT (mA)
SOURCE CURRENT (mA)
_______________________________________________________________________________________
5
SOT23, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
Typical Operating Characteristics (continued)
(V
CC
= +5V, V = 0, C = 15pF, V
= 100mV, T = +25°C, unless otherwise noted.)
A
OVERDRIVE
EE
L
MAX917/MAX919
SHORT-CIRCUIT SOURCE CURRENT
vs. TEMPERATURE
MAX917/MAX919
OUTPUT VOLTAGE HIGH vs.
SOURCE CURRENT AND TEMPERATURE
SHORT-CIRCUIT SINK CURRENT
vs. TEMPERATURE
140
120
100
80
120
0.6
V
CC
= 5V
100
80
60
40
20
0
0.5
0.4
0.3
0.2
0.1
0
V
= 5V
= 3V
CC
T
A
= +25°C
T
= +85°C
A
60
V
= 3V
CC
V
CC
40
T
A
= -40°C
20
V
= 1.8V
35
CC
17–MAX920
V
= 1.8V
CC
0
-40
-15
10
60
85
-40
-15
10
35
60
85
0
2
4
6
8
10 12 14 16 18 20
TEMPERATURE (°C)
TEMPERATURE (°C)
SOURCE CURRENT (mA)
MAX917/MAX918
REFERENCE VOLTAGE vs. TEMPERATURE
HYSTERESIS VOLTAGE vs. TEMPERATURE
5.0
OFFSET VOLTAGE vs. TEMPERATURE
0.10
0.09
0.08
0.07
0.06
0.05
0.04
0.03
1.246
1.245
1.244
1.243
1.242
1.241
V
= 5V
= 3V
CC
V
CC
= 1.8V
4.5
4.0
3.5
3.0
2.5
V
CC
V
CC
= 3V
V
= 1.8V
CC
V
CC
= 5V
-40
-15
10
35
60
85
-40
-15
10
35
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
MAX917/MAX918
REFERENCE VOLTAGE vs.
SUPPLY VOLTAGE
MAX917/MAX918
REFERENCE OUTPUT VOLTAGE vs.
REFERENCE SOURCE CURRENT
MAX917/MAX918
REFERENCE OUTPUT VOLTAGE vs.
REFERENCE SINK CURRENT
1.2440
1.2435
1.2430
1.2425
1.2420
1.2415
1.2460
1.2460
1.2455
1.2450
1.2445
1.2440
1.2435
V
= 1.8V
CC
V
= 3V
CC
1.2455
1.2450
1.2445
1.2440
V
= 1.8V
CC
V
= 3V
CC
V
= 5V
CC
V
CC
= 5V
1.5 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
0
1
2
3
4
5
6
7
8
9
10
SUPPLY VOLTAGE (V)
SOURCE CURRENT (nA)
SINK CURRENT (nA)
6
_______________________________________________________________________________________
SOT23, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
17–MAX920
Typical Operating Characteristics (continued)
(V
CC
= +5V, V = 0, C = 15pF, V
= 100mV, T = +25°C, unless otherwise noted.)
A
OVERDRIVE
EE
L
MAX917/MAX919
PROPAGATION DELAY (t
vs. TEMPERATURE
PROPAGATION DELAY (t
vs. TEMPERATURE
)
PROPAGATION DELAY (t
vs. CAPACITIVE LOAD
)
PD-
PD-
)
PD+
140
120
30
120
100
80
60
40
20
0
V
= 1.8V
CC
25
20
15
10
5
V
CC
= 1.8V
V
CC
= 5V
100
80
V
= 5V
CC
V
CC
= 3V
V
CC
= 3V
V
= 3V
V
CC
60
40
20
0
= 1.8V
CC
V
CC
= 5V
0
-40
-15
10
35
60
85
-40
-15
10
35
60
85
0.01
0.1
1
10
100
1000
TEMPERATURE (°C)
TEMPERATURE (°C)
CAPACITIVE LOAD (nF)
MAX917/MAX919
PROPAGATION DELAY (t
vs. CAPACITIVE LOAD
MAX917/MAX919
PROPAGATION DELAY (t
vs. INPUT OVERDRIVE
)
PROPAGATION DELAY (t
vs. INPUT OVERDRIVE
)
PD+
PD-
)
PD+
100
90
80
70
60
50
40
30
20
10
0
160
140
120
100
80
70
60
50
40
30
20
10
V
= 3V
CC
V
CC
= 1.8V
V
= 5V
CC
CC
V
= 5V
CC
V
V
= 3V
60
V
V
= 3V
CC
V
CC
= 5V
= 1.8V
40
CC
= 1.8V
CC
20
0
0.01
0
10
20
30
40
50
0.1
1
10
100
1000
0
10
20
30
40
50
INPUT OVERDRIVE (mV)
CAPACITIVE LOAD (nF)
INPUT OVERDRIVE (mV)
MAX918/MAX920
MAX918/MAX920
PROPAGATION DELAY (t ) vs.
PROPAGATION DELAY (t ) vs.
PD+
PD-
PROPAGATION DELAY (t
)
PD-
PULL-UP RESISTANCE
PULL-UP RESISTANCE
(V = 5V)
CC
MAX917-920 toc27
20
19
18
17
16
15
14
250
200
150
100
50
V
= 1.8V
CC
IN+
(50mV/
div)
V
= 3V
= 5V
CC
V
= 5V
= 3V
CC
OUT
(2V/div)
V
CC
V
CC
V
= 1.8V
CC
0
10
100
1k
10k
10
100
1k
10k
20µs/div
R
(kΩ)
R
(kΩ)
PULL-UP
PULL-UP
_______________________________________________________________________________________
7
SOT23, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
Typical Operating Characteristics (continued)
(V
CC
= +5V, V = 0, C = 15pF, V
= 100mV, T = +25°C, unless otherwise noted.)
OVERDRIVE
A
EE
L
MAX917/MAX919
PROPAGATION DELAY (t
MAX917/MAX919
PROPAGATION DELAY (t
PROPAGATION DELAY (t
)
)
)
PD+
PD-
PD+
(V = 3V)
(V = 5V)
CC
(V = 3V)
CC
CC
MAX917-920 toc29
MAX917-920 toc28
MAX917-920 toc30
IN+
(50mV/
div)
IN+
(50mV/
div)
IN+
(50mV/
div)
OUT
(2V/div)
OUT
OUT
(2V/div)
(2V/div)
17–MAX920
20µs/div
20µs/div
20µs/div
MAX917/MAX919
PROPAGATION DELAY (t
PROPAGATION DELAY (t
)
)
MAX917/MAX919
10kHz RESPONSE (V = 1.8V)
CC
MAX917-920 toc33
PD-
PD+
(V = 1.8V)
(V = 1.8V)
CC
CC
MAX917-920 toc31
MAX917-920 toc32
IN+
(50mV/
div)
IN+
(50mV/
div)
IN+
(50mV/
div)
OUT
(1V/div)
OUT
(1V/div)
OUT
(1V/div)
20µs/div
20µs/div
20µs/div
MAX917/MAX919
1kHz RESPONSE (V = 5V)
CC
POWER-UP/DOWN RESPONSE
MAX917-920 toc34
MAX917-920 toc35
IN+
(50mV/div)
V
CC
(2V/div)
OUT
(2V/div)
OUT
(2V/div)
200µs/div
40µs/div
8
_______________________________________________________________________________________
SOT23, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
17–MAX920
Functional Diagrams
V
CC
V
CC
IN+
IN+
IN-
OUT
OUT
REF
MAX919
MAX920
MAX917
MAX918
REF
1.245V
V
EE
V
EE
Pin Description
PIN
NAME
FUNCTION
MAX917/MAX918
MAX919/MAX920
SOT23-5
SO
SOT23-5
SO
1
2
6
1
2
6
OUT
Comparator Output
4
4
V
EE
Negative Supply Voltage
3
3
—
3
3
2
IN+
IN-
Comparator Noninverting Input
Comparator Inverting Input
—
4
4
2
—
5
—
REF
1.245V Reference Output and Comparator Inverting Input
Positive Supply Voltage
5
7
7
V
CC
—
1, 5, 8
—
1, 5, 8
N.C.
No Connection. Not internally connected.
output stage that sinks as well as sources current. The
MAX918/MAX920 have an open-drain output stage that
Detailed Description
The MAX917/MAX918 feature an on-board 1.245V
1.5ꢀ reference, yet draw an ultra-low supply current
of 750nA. The MAX919/MAX920 (without reference)
consume just 380nA of supply current. All four devices
are guaranteed to operate down to +1.8V. Their com-
mon-mode input voltage range extends 200mV
beyond-the-rails. Internal hysteresis ensures clean out-
put switching, even with slow-moving input signals.
Large internal output drivers allow rail-to-rail output
swing with up to 8mA loads.
can be pulled beyond V
to an absolute maximum of
CC
6V above V . These open-drain versions are ideal for
EE
implementing wire-Or output logic functions.
Input Stage Circuitry
The input common-mode voltage range extends from
V
EE
- 0.2V to V
+ 0.2V. These comparators operate
CC
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 pro-
tected from overvoltage by internal ESD protection
diodes connected to the supply rails. As the input volt-
age exceeds the supply rails, these ESD protection
diodes become forward biased and begin to conduct.
The output stage employs a unique design that mini-
mizes supply-current surges while switching, virtually
eliminating the supply glitches typical of many other
comparators. The MAX917/MAX919 have a push/pull
_______________________________________________________________________________________
9
SOT23, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
Output Stage Circuitry
V
CC
The MAX917–MAX920 contain a unique break-before-
make output stage capable of rail-to-rail operation with
up to 8mA loads. Many comparators consume orders
of magnitude more current during switching than dur-
ing steady-state operation. However, with this family of
comparators, the supply-current change during an out-
put transition is extremely small. In the Typical Oper-
ating 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.
120nA
REF
V
EE
Figure 1. MAX917/MAX918 Voltage Reference Output
Equivalent Circuit
17–MAX920
Reference (MAX917/MAX918)
Internal Hysteresis
The internal reference in the MAX917/MAX918 has an
Many comparators oscillate in the linear region of oper-
ation because of noise or undesired parasitic feed-
back. This tends to occur when the voltage on one
input is equal or very close to the voltage on the other
input. The MAX917–MAX920 have internal hysteresis to
counter parasitic effects and noise.
output voltage of +1.245V with respect to V . Its typi-
EE
cal temperature coefficient is 95ppm/°C over the full
-40°C to +85°C temperature range. The reference is a
PNP emitter-follower driven by a 120nA current source
(Figure 1). The output impedance of the voltage refer-
ence is typically 200kΩ, 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 MAX406.
The hysteresis in a comparator creates two trip points:
one for the rising input voltage (V
) and one for the
THR
falling input voltage (V
) (Figure 2). The difference
THF
between the trip points is the hysteresis (V ). When
HB
the comparator’s input voltages are equal, the hystere-
sis effectively causes one comparator input to move
quickly past the other, thus taking the input out of the
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.
Applications Information
Low-Voltage, Low-Power Operation
The MAX917–MAX920 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 MAX917–MAX920, assuming nominal conditions.
Table 1. Battery Applications Using MAX917–MAX920
CAPACITY,
AA SIZE
(mA-h)
MAX917/MAX918
OPERATING TIME
(hr)
MAX919/MAX920
OPERATING TIME
(hr)
BATTERY
TYPE
V
V
FRESH
(V)
END-OF-LIFE
(V)
RECHARGEABLE
Alkaline
(2 Cells)
6
6
No
Yes
Yes
3.0
2.4
3.5
1.8
1.8
2.7
2000
750
2.5 x 10
5 x 10
Nickel-Cadmium
(2 Cells)
6
937,500
1.875 x 10
Lithium-Ion
(1 Cell)
6
6
1000
1.25 x 10
2.5 x 10
Nickel-Metal-
Hydride
(2 Cells)
6
6
Yes
2.4
1.8
1000
1.25 x 10
2.5 x 10
10 ______________________________________________________________________________________
SOT23, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
17–MAX920
V
CC
THRESHOLDS
R3
IN+
IN-
V
V
THR
R1
V
IN
HYSTERESIS
BAND
V
CC
V
OUT
HB
R2
V
THF
EE
MAX917
MAX919
V
REF
OUT
Figure 3. MAX917/MAX919 Additional Hysteresis
Figure 2. Threshold Hysteresis Band
R2 = 1/[3.0V/(1.2V · 12kΩ) - (1 / 12kΩ) -
(1/1.2MΩ)] = 8.05kΩ
Additional Hysteresis (MAX917/MAX919)
The MAX917/MAX919 have a 4mV internal hysteresis
band (V ). Additional hysteresis can be generated
HB
For this example, choose an 8.2kΩ standard value.
with three resistors using positive feedback (Figure 3).
Unfortunately, this method also slows hysteresis re-
sponse time. Use the following procedure to calculate
resistor values.
6) Verify the trip voltages and hysteresis as follows:
V
IN
rising: V
= V
· R1 [(1 / R1) + (1 / R2)
THR
+ (1 / R3)]
REF
1) Select R3. Leakage current at IN is under 2nA, so
the current through R3 should be at least 0.2µA to
minimize errors caused by leakage current. The cur-
V
IN
falling: V = V
- (R1 · V / R3)
CC
THF
THR
Hysteresis = V
- V
THF
THR
rent through R3 at the trip point is (V
- V )/R3.
OUT
REF
Considering the two possible output states in solving
for R3 yields two formulas: R3 = V /I or R3 =
Additional Hysteresis (MAX918/MAX920)
The MAX918/MAX920 have a 4mV internal hysteresis
band. They have open-drain outputs and require an
external pull-up resistor (Figure 4). Additional hystere-
sis can be generated using positive feedback, but the
formulas differ slightly from those of the MAX917/
MAX919. Use the following procedure to calculate
resistor values.
REF R3
(V
- V
)/I . Use the smaller of the two resulting
CC
REF R3
resistor values. For example, when using the
MAX917 (V
= 1.245V) and V
= 5V, and if we
REF
CC
choose I = 1µA, then the two resistor values are
R3
1.2MΩ and 3.8MΩ. Choose a 1.2MΩ standard value
for R3.
2) Choose the hysteresis band required (V ). For this
HB
1) Select R3 according to the formulas R3 = V
/ 1µA
REF
example, choose 50mV.
or R3 = (V
- V
)/1µA - R4. Use the smaller of
CC
REF
the two resulting resistor values.
3) Calculate R1 according to the following equation:
2) Choose the hysteresis band required (V ).
HB
R1 = R3 (V / V
)
CC
HB
3) Calculate R1 according to the following equation:
For this example, insert the values
R1 = 1.2MΩ (50mV/5V) = 12kΩ
4) Choose the trip point for V rising (V
R1 = (R3 + R4) (V /V
)
HB CC
4) Choose the trip point for V rising (V
) (V
is
IN
THR
THF
) such that
THR
IN
the trip point for V falling). This is the threshold
IN
V
V
> V
· (R1 + R3)/R3 (V
is the trip point for
THR
REF
THF
voltage at which the comparator switches its output
from low to high as V rises above the trip point.
IN
falling). This is the threshold voltage at which the
IN
comparator switches its output from low to high as
5) Calculate R2 as follows:
V
rises above the trip point. For this example,
IN
choose 3V.
1
1
R2 = 1/ V
/ V
R1 −
−
THR REF
(
)
5) Calculate R2 as follows:
R1 R3
R2 = 1/[V /(V
THR REF
· R1) - (1 / R1) - (1 / R3)]
______________________________________________________________________________________ 11
SOT23, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
6) Verify the trip voltages and hysteresis as follows:
Zero-Crossing Detector
Figure 5 shows a zero-crossing detector application.
The MAX919’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.
1
1
1
V
rising:V
= V
REF
R1
+
+
IN
THR
R1 R2 R3
V
falling:V
=
IN
THF
1
1
1
R1
V
R1
+
+
−
V
CC
REF
Logic-Level Translator
The Typical Application Circuit shows an application
that converts 5V logic to 3V logic levels. The MAX920 is
powered by the +5V supply voltage, and the pull-up
resistor for the MAX920’s open-drain output is connect-
ed 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,
R1 R2 R3 +R4
Hysteresis = V - V
R3 +R4
THR
THF
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 sur-
face-mount components are recommended.
simply connect the +3V supply voltage to V
+5V supply voltage to the pull-up resistor.
and the
CC
17–MAX920
V
CC
V
CC
100mVp-p
V
CC
IN+
IN-
R3
OUT
R1
R4
V
IN
V
V
CC
OUT
MAX919
R2
EE
V
EE
MAX918
MAX920
V
REF
Figure 5. Zero-Crossing Detector
Typical Application Circuit
Figure 4. MAX918/MAX920 Additional Hysteresis
+5V (+3V)
Pin Configurations (continued)
+3V (+5V)
TOP VIEW
100k
100k
V
CC
R
PULL-UP
IN-
IN+
N.C.
IN- (REF)
IN+
1
2
3
4
8
7
6
5
N.C.
3V (5V)
LOGIC OUT
OUT
V
CC
MAX917
MAX918
MAX919
MAX920
OUT
N.C.
MAX920
V
EE
V
EE
SO
5V (3V) LOGIC IN
LOGIC LEVEL
TRANSLATOR
( ) ARE FOR MAX917/MAX918.
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.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 1999 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
相关型号：
MAX9210EUM+
Line Receiver, 4 Func, 4 Driver, 4 Rcvr, CMOS, PDSO48, 6.10 MM, MO-153ED, TSSOP-48
MAXIM
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