19-1141; Rev 2; 2/07
Single/Dual, +3V/+5V Dual-Speed
Comparators with Auto-Standby
General Description
The MAX975/MAX977 single/dual comparators feature
three different operating modes, and are optimized for
+3V and +5V single-supply applications. The operating
modes are as follows: high speed, high speed with
auto-standby, and low power. Propagation delay is 28ns
in high-speed mode, while supply current is only 250µA.
Supply current is reduced to 3µA in low-power mode.
The auto-standby feature allows the comparator to
automatically change from low-power mode to high-
speed mode upon receipt of an input signal. In the
absence of an input signal, the comparator reverts
back to low-power mode after an adjustable timeout
period. The timeout period for the MAX975 to enter
standby is set by a single capacitor. The dual MAX977
features independently adjustable timeout periods for
each comparator using separate capacitors.
The MAX975/MAX977’s inputs have a common-mode
voltage range of -0.2V to (V
CC
- 1.2V). The differential
input voltage range extends rail to rail. The outputs are
capable of rail-to-rail operation without external pull-up
circuitry, making these devices ideal for interface with
CMOS/TTL logic. All inputs and outputs can tolerate a
continuous short-circuit fault condition to either rail. The
comparator’s internal hysteresis in high-speed mode
ensures clean output switching, even with slow-moving
input signals.
The single MAX975 is available in 8-pin SO and 8-pin
µMAX
®
packages, while the dual MAX977 is available
in 14-pin SO and 16-pin QSOP packages.
____________________________Features
♦
Three Operating Modes:
High Speed
High Speed with Auto-Standby
Low Power
♦
28ns Propagation Delay (high-speed mode)
♦
5µA Max Supply Current in Low-Power/
Auto-Standby Modes
♦
+3V/+5V Single-Supply Operation
♦
Rail-to-Rail Outputs
♦
Ground-Sensing Input
♦
Internal Hysteresis (high-speed mode)
♦
Adjustable Timeout Period
♦
µMAX Package (MAX975)
QSOP-16 Package (MAX977)
MAX975/MAX977
Ordering Information
PART
MAX975ESA
MAX975EUA-T
MAX977ESD
MAX977EEE
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-
PACKAGE
8 SO
8 µMAX-8
14 SO
16 QSOP
PKG
CODE
S8-2
U8-1
S14-1
E16-1
Functional Diagram
________________________Applications
Battery-Powered Systems
RF ID Tags
Keyless Entry
Threshold Detectors/Discriminators
3V Systems
IR Receivers
Digital-Line Receivers
IN+
V
CC
MAX975
LP
HIGH SPEED
ENABLE
TRANSITION
MONITOR
OUT
LOW POWER
ENABLE
IN-
GND
µMAX is a registered trademark of Maxim Integrated Products, Inc.
Pin Configurations appear at end of data sheet.
STAT
TIMING
CIRCUIT
STO
________________________________________________________________
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.
Single/Dual, +3V/+5V Dual-Speed
Comparators with Auto-Standby
MAX975/MAX977
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V
CC)
............................................................+6V
All Other Pins..............................................-0.3V to (V
CC
+ 0.3V)
Current into Input Pins ......................................................±20mA
Duration of Output Short Circuit to GND_ or V
CC
......Continuous
Continuous Power Dissipation (T
A
= +70°C)
8-Pin SO (derate 5.88mW/°C above +70°C)..................471mW
8-Pin µMAX (derate 4.10mW/°C above +70°C) .............330mW
14-Pin SO (derate 8.33mW/°C above +70°C)................667mW
16-Pin QSOP (derate 8.33mW/°C above +70°C)...........667mW
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
(V
CC
= +2.7V to +5.25V, specifications are for high-speed mode, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at
T
A
= +25°C.) (Note 1)
PARAMETER
POWER SUPPLY
Supply-Voltage
Operating Range
Supply Current
Per Comparator
Power-Supply
Rejection Ratio
COMPARATOR INPUTS
Common-Mode
Voltage Range
V
CMR
(Note 2)
High-speed mode, T
A
= +25°C
Input Offset Voltage
(Note 3)
V
OS
V
CM
= 1V,
V
CC
= 5V
High-speed mode, T
A
= T
MIN
to T
MAX
Auto-standby/
low-power modes,
T
A
= T
MIN
to T
MAX
SO
µMAX/QSOP
SO
µMAX/QSOP
SO
µMAX/QSOP
0.5
0.3
±1
±1
2
2
-100
-100
-5
±20
3
-0.2V
≤
V
CM
≤
V
CC
- 1.2V
High-speed mode
Low-power mode
SO
µMAX/QSOP
66
54
82
90
dB
±100
nA
pF
-0.2
+0.2
V
CC
- 1.2
±2
±3
±5
±7
4
4
-300
-400
nA
mV
mV
V
V
CC
High-speed mode
I
CC
Auto-standby/low-power modes
V
CM
= 1V,
2.7V
≤
V
CC
≤
5.25V
SO
µMAX/QSOP
63
2.7
250
3
3
90
77
5.25
500
5
6
dB
µA
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
PSRR
High-speed mode
Low-power mode
Input-Referred Hysteresis
V
HYS
V
CM
= 1V, V
CC
= 5V (Note 4)
High-speed mode
Auto-standby/low-power modes
Input Bias Current
Input Offset Current
Input Capacitance
Common-Mode
Rejection Ratio
I
B
I
OS
C
IN
CMRR
2
_______________________________________________________________________________________
Single/Dual, +3V/+5V Dual-Speed
Comparators with Auto-Standby
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +2.7V to +5.25V, specifications are for high-speed mode, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at
T
A
= +25°C.) (Note 1)
PARAMETER
DIGITAL INPUTS
LP Input Voltage High
LP Input Voltage Low
LP Fall Time
LP Input Current
STO_ Input Voltage Low
STO_ Source Current
DIGITAL OUTPUTS
OUT_ Output Voltage High
OUT_ Output Voltage Low
Propagation Delay, Low to High
(Note 6)
V
OH
V
OL
I
SOURCE
= 2mA, all modes
I
SINK
= 2mA, all modes
C
LOAD
= 10pF,
V
CC
= 5V
High-speed mode,
overdrive = 5mV
Low-power mode,
overdrive = 10mV
High-speed mode,
overdrive = 5mV
Low-power mode,
overdrive = 10mV
V
CC
- 0.4 V
CC
- 0.1
0.1
28
0.82
28
0.48
2
1
1.6
1.6
V
CC
- 0.4
0.4
High-speed mode
Low-power mode
0.4
50
1.6
50
1.6
V
V
ns
µs
ns
µs
ns
ns
ns
V
V
V
LPIH
V
LPIL
t
LP
I
LPB
V
CIL
I
STO
V
CC
= 3V
(Note 5)
0.01
V
CC
/ 2
0.15
0.7 x V
CC
V
CC
/ 2
V
CC
/ 2
0.3 x V
CC
10
±1
0.3 x V
CC
V
V
µs
µA
V
µA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX975/MAX977
t
PD+
Propagation Delay, High to Low
(Note 6)
Propagation-Delay Skew (Note 6)
Propagation-Delay Matching
Rise/Fall Time
STAT_ Output Voltage High
STAT_ Output Voltage Low
t
PD-
C
LOAD
= 10pF,
V
CC
= 5V
C
LOAD
= 10pF
t
SKEW
∆t
PD
MAX977 only, C
LOAD
= 10pF
C
LOAD
= 10pF,
V
CC
= 5.0V
V
SH
V
SL
I
SOURCE
= 3mA, all modes
I
SINK
= 400µA, all modes
Note 1:
The MAX975EUA is 100% production tested at T
A
= +25°C; all temperature specifications are guaranteed by design.
Note 2:
Inferred by CMRR. Either input can be driven to the absolute maximum limit without false output inversion, as long as the
other input is within the specified common-mode input voltage range.
Note 3:
V
OS
is defined as the mean of trip points. The trip points are the extremities of the differential input voltage required to make
the comparator output change state (Figure 1).
Note 4:
The difference between the upper and lower trip points is equal to the width of the input-referred hysteresis zone (Figure 1).
Note 5:
Guaranteed by design. The LP pin is sensitive to noise. If fall times larger than 10µs are expected, bypass LP to ground
using a 0.1µF capacitor.
Note 6:
Propagation delay is guaranteed by design. For low-overdrive conditions, V
OS
is added to the overdrive. The following
equation defines propagation-delay skew: t
SKEW
= t
PD+
- t
PD-
.
_______________________________________________________________________________________
3
Single/Dual, +3V/+5V Dual-Speed
Comparators with Auto-Standby
MAX975/MAX977
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +2.7V to +5.25V, specifications are for high-speed mode, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at
T
A
= +25°C.) (Note 1)
PARAMETER
Auto-Standby Timeout
Auto-Standby Enable Time
Auto-Standby Wake-Up Time
Auto-Standby Wake-Up Input
or LP Pulse Width
Auto-Standby Comparator
Disable
Low-Power Enable Time
High-Speed Enable Time
Low-Power Comparator Disable
Low-Power STAT_ High
SYMBOL
t
ASB
t
ASBE
t
ASD
t
PWD
t
ASCD
t
LPE
t
HSE
t
LPCD
t
LPSH
(Note 8)
(Note 9)
10mV overdrive (Note 10)
10mV overdrive (Note 11)
(Note 12)
(Note 13)
(Note 14)
(Note 15)
(Note 16)
1.6
0.8
3
1.1
0.7
20
4
CONDITIONS
MIN
5
TYP
10
3
2
4
MAX
16
UNITS
ms
µs
µs
µs
µs
µs
µs
µs
ns
AUTO-STANDBY/LOW-POWER TIMING
(Note 7; Figure 2)
Note 7:
Note 8:
Note 9:
Note 10:
Note 11:
Note 12:
Note 13:
Note 14:
Note 15:
Note 16:
Timing specifications are guaranteed by design.
Set by 1000pF external capacitor at the STO_ pin. t
ASB
is defined as the time from last input transition to STAT_ = high.
Does not include time to go into standby condition (t
ASBE)
.
t
ASBE
is defined as the time from when STAT_ goes high to when the supply current drops to 5µA.
t
ASD
is defined as the time from the last input transition to when STAT_ goes low. The comparator is in high-speed mode
before STAT_ is low.
t
PWD
is defined as the minimum input or LP pulse width to trigger fast-mode operation from auto-standby.
t
ASCD
is defined as the time from the last input transition to when the supply current increases to 300µA.
t
LPE
is defined as the time from when LP is driven high to when the supply current drops to 5µA.
t
HSE
is defined as the time from when LP goes low to when STAT goes low. The comparator is in high-speed mode before
STAT_ is low.
t
LPCD
is defined as the time from when LP goes low to when the supply current increases to 300µA.
t
LPSH
is defined as the time from when LP goes high to when STAT_ goes high.
4
_______________________________________________________________________________________
Single/Dual, +3V/+5V Dual-Speed
Comparators with Auto-Standby
MAX975/MAX977
__________________________________________Typical Operating Characteristics
(V
CC
= 3.0V, T
A
= +25°C, unless otherwise noted.)
LOW-POWER OFFSET VOLTAGE
vs. TEMPERATURE
-0.60
-0.65
-0.70
-0.75
-0.80
-0.85
-0.90
-0.95
-1.00
-1.05
-1.10
-1.15
-1.20
-60 -40 -20
0
20
40
60
80
100
TEMPERATURE (°C)
MAX977-01
SUPPLY CURRENT PER COMPARATOR
vs. OUTPUT TRANSITION FREQUENCY
MAX977-02
HIGH-SPEED INPUT BIAS CURRENT
vs. TEMPERATURE
MAX977-03
10000
-50
-70
V
CC
= 3V
-90
-110
-130
-150
V
CC
= 3V
OFFSET VOLTAGE (mV)
SUPPLY CURRENT
PER COMPARATOR (µA)
1000
HIGH-SPEED MODE
100
INPUT BIAS CURRENT (nA)
V
CC
= 5V
10
LOW-POWER MODE
1
0.01k 0.1k
-170
1k
10k 100k 1M
10M 100M
-60 -40 -20
0
20
40
60
80
100
TEMPERATURE (°C)
TRANSITION FREQUENCY (kHz)
LOW-POWER INPUT BIAS CURRENT
vs. TEMPERATURE
MAX977-04
HIGH-SPEED VOLTAGE TRIP POINTS/INPUT
OFFSET VOLTAGE vs. TEMPERATURE
MAX977-05
HIGH-SPEED VOLTAGE TRIP POINTS/INPUT
OFFSET VOLTAGE vs. TEMPERATURE
TRIP POINTS/OFFSET VOLTAGE (mV)
1.2
1.0
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1.0
-1.2
-60 -40 -20
0
20
V
CC
= 3V
V
TRIP+
MAX977-06
7.0
6.5
INPUT BIAS CURRENT (nA)
6.0
5.5
V
CC
= 5V
5.0
4.5
V
CC
= 3V
4.0
3.5
3.0
-60 -40 -20
0
20
40
60
80
1.0
TRIP POINTS/OFFSET VOLTAGE (mV)
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1.0
-60 -40 -20
0
20
40
60
80
V
TRIP-
V
OS
V
CC
= 5V
V
TRIP+
V
OS
V
TRIP-
100
100
40
60
80
100
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
LOW-POWER PROPAGATION DELAY
vs. CAPACITIVE LOAD
MAX977-07
LOW-POWER PROPAGATION DELAY
vs. INPUT OVERDRIVE
MAX977-08
AUTO-STANDBY TIMEOUT
vs. TEMPERATURE
10.1
10.0
MAX977-09
600
550
PROPAGATION DELAY (ns)
500
450
400
350
300
250
200
0
50
100
150
200
V
CC
= 3V
t
PD-
V
CC
= 5V
50mV OVERDRIVE
V
CC
= 3V
V
CC
= 5V
t
PD
+
700
650
PROPAGATION DELAY (ns)
600
550
500
450
400
350
300
250
200
150
0
40
80
V
CC
= 5V
120
160
200
V
CC
= 3V
t
PD-
V
CC
= 3V
V
CC
= 5V
t
PD+
C
LOAD
=15pF
10.2
TIMEOUT (ms)
9.9
9.8
9.7
9.6
9.5
9.4
9.3
V
CC
= 5V
V
CC
= 3V
250
240
-60 -40 -20
0
20
40
60
80
100
CAPACITIVE LOAD (pF)
INPUT OVERDRIVE (mV)
TEMPERATURE (°C)
_______________________________________________________________________________________
5
Embedded System
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