MAXIM MAX9025_11

19-3241; Rev 1; 6/11
UCSP, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
The MAX9025–MAX9028 nanopower comparators in
space-saving chip-scale (UCSP™) packages feature
Beyond-the-Rails™ inputs and are guaranteed to operate down to +1.8V. The MAX9025/MAX9026 feature an
on-board 1.236V ±1% reference and draw an ultra-low
supply current of only 1µA, while the MAX9027/
MAX9028 (without reference) require just 0.6µA of supply
current. These features make the MAX9025–MAX9028
family of comparators ideal for all 2-cell batterymonitoring/management applications.
The unique design of the output stage limits supplycurrent surges while switching, virtually eliminating the
supply glitches typical of many other comparators. This
design also minimizes overall power consumption under
dynamic conditions. The MAX9025/MAX9027 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 5mA. The MAX9026/MAX9028
have an open-drain output stage that makes them suitable for mixed-voltage system design. All devices are
available in the miniature 6-bump UCSP packages.
Refer to the MAX9117 data sheet for similar comparators
in 5-pin SC70 packages and the MAX9017 data sheet for
similar dual comparators in 8-pin SOT23 packages.
Applications
2-Cell Battery Monitoring/Management
Ultra-Low-Power Systems
Features
♦ Space-Saving UCSP Package (1mm x 1.52mm)
♦ Ultra-Low Supply Current
0.6µA (MAX9027/MAX9028)
1µA with Reference (MAX9025/MAX9026)
♦ Guaranteed to Operate Down to +1.8V
♦ Internal 1.236V ±1% Reference (MAX9025/MAX9026)
♦ Input Voltage Range Extends 200mV
Beyond-the-Rails
♦ CMOS Push-Pull Output with ±5mA Drive
Capability (MAX9025/MAX9027)
♦ Open-Drain Output Versions Available
(MAX9026/MAX9028)
♦ Crowbar-Current-Free Switching
♦ Internal Hysteresis for Clean Switching
♦ No Phase Reversal for Overdriven Inputs
Ordering Information
PART
TEMP
RANGE
BUMPPACKAGE
TOP
MARK
MAX9025EBT+T
-40°C to +85°C
6 UCSP
ADB
MAX9026EBT+T
-40°C to +85°C
6 UCSP
ADC
MAX9027EBT+T
-40°C to +85°C
6 UCSP
ADD
MAX9028EBT+T
-40°C to +85°C
6 UCSP
ADE
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
Mobile Communications
Notebooks and PDAs
Pin Configurations
Sensing at Ground or Supply Line
Telemetry and Remote Systems
TOP VIEW
(BUMPS ON BOTTOM)
Medical Instruments
1
B
A
IN+
VCC
Selector Guide
INTERNAL
REFERENCE
OUTPUT
TYPE
SUPPLY
CURRENT
(µA)
MAX9025
Yes
Push-Pull
1.0
MAX9026
Yes
Open-Drain
1.0
MAX9027
No
Push-Pull
0.6
MAX9028
No
Open-Drain
0.6
PART
MAX9025–
MAX9028
2
REF
(VEE)
OUT
3
IN-
VEE
Typical Application Circuit appears at end of data sheet.
Beyond-the-Rails and UCSP are trademarks of Maxim Integrated
Products, Inc.
( ) MAX9027/MAX9028 PINS
UCSP
________________________________________________________________ Maxim Integrated Products
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.
1
MAX9025–MAX9028
General Description
MAX9025–MAX9028
UCSP, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VCC to VEE)..................................................+6V
Voltage Inputs (IN+, IN-, REF) .........(VEE - 0.3V) to (VCC + 0.3V)
Output Voltage
MAX9025/MAX9027 ....................(VEE - 0.3V) to (VCC + 0.3V)
MAX9026/MAX9028 ..................................(VEE - 0.3V) to +6V
Current into Input Pins ........................................................20mA
Output Current..................................................................±50mA
Output Short-Circuit Duration .................................................10s
Continuous Power Dissipation (TA = +70°C)
6-Bump UCSP (derate 3.9mW/°C above +70°C)........308mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Bump Temperature (soldering) Reflow............................+235°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—MAX9025/MAX9026 (WITH REF)
(VCC = +5V, VEE = 0V, VIN+ = VREF, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
Supply Voltage Range
VCC
Supply Current
ICC
CONDITIONS
Inferred from the PSRR test
MIN
VCC = 1.8V
VCC = 5V
TA = +25°C
VIN+
Inferred from output swing test
Input Offset Voltage
VOS
(Note 2)
Input-Referred Hysteresis
VHB
(Note 3)
Power-Supply Rejection Ratio
Output Voltage Swing High
Output Voltage Swing Low
Output Leakage Current
IB
PSRR
VCC VOH
VOL
ILEAK
High-to-Low Propagation Delay
(Note 4)
2
tPD-
1.5
VEE 0.2
VCC +
0.2
0.3
5
10
4
MAX9025, VCC = 5V,
ISOURCE = 6mA
MAX9025, VCC =
1.8V, ISOURCE = 1mA
TA = +25°C
VCC = 5V,
ISINK = 6mA
TA = +25°C
VCC = 1.8V,
ISINK = 1mA
TA = +25°C
0.1
1
250
350
56
200
TA = TMIN to TMAX
450
TA = TMIN to TMAX
250
350
57
200
450
TA = TMIN to TMAX
VCC = 5V
nA
mV/V
mV
mV
300
0.001
1
µA
35
VCC = 1.8V
3
VCC = 5V
33
VCC = 1.8V
mV
300
TA = TMIN to TMAX
MAX9026 only, VO = 5.5V
V
mV
1
2
TA = +25°C
µA
2.2
0.15
VCC = 1.8V to 5.5V
Sinking, VO = VCC
V
1.7
TA = TMIN to TMAX
ISC
UNITS
5.5
0.8
TA = TMIN to TMAX
TA = +25°C
Sourcing, VO = VEE
Output Short-Circuit Current
TA = +25°C
MAX
1.0
TA = TMIN to TMAX
IN+ Voltage Range
Input Bias Current
TYP
1.8
mA
3
VCC = 1.8V
7
VCC = 5V
6
_______________________________________________________________________________________
µs
UCSP, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
MAX9025–MAX9028
ELECTRICAL CHARACTERISTICS—MAX9025/MAX9026 (WITH REF) (continued)
(VCC = +5V, VEE = 0V, VIN+ = VREF, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
VCC = 1.8V
MAX9025 only
TYP
MAX
UNITS
11
VCC = 5V
28
VCC = 1.8V
12
Low-to-High Propagation Delay
(Note 4)
tPD+
Rise Time
tRISE
MAX9025 only, CL = 15pF
1.6
µs
Fall Time
tFALL
CL = 15pF
0.2
µs
Power-Up Time
MAX9026 only,
RPULLUP = 100kΩ
VCC = 5V
31
tON
Reference Voltage
VREF
Reference Voltage Temperature
Coefficient
TCREF
Reference Output Voltage Noise
EN
µs
1.2
TA = +25°C
1.224
TA = TMIN to TMAX
1.205
1.236
ms
1.248
1.267
ppm/
°C
40
CREF = 1nF
BW = 10Hz to 100kHz
29
BW = 10Hz to 6kHz
60
V
µVRMS
Reference Line Regulation
∆VREF/
∆VCC
VCC = 1.8V to 5.5V
0.5
mV/V
Reference Load Regulation
∆VREF/
∆IOUT
∆IOUT = 0nA to 100nA
0.03
mV/
nA
ELECTRICAL CHARACTERISTICS—MAX9027/MAX9028 (WITHOUT REF)
(VCC = +5V, VEE = 0V, VCM = 0V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
Supply Voltage Range
VCC
Supply Current
ICC
CONDITIONS
Inferred from the PSRR test
MIN
VCC = 1.8V
VCC = 5V
0.45
TA = +25°C
VCM
Inferred from the CMRR test
Input Offset Voltage
VOS
-0.2V ≤ VCM ≤
(VCC + 0.2V)
(Note 2)
Input Bias Current
VHB
IB
0.6
TA = TMIN to TMAX
Input Common-Mode
Voltage Range
Input-Referred Hysteresis
TYP
1.8
TA = +25°C
MAX
UNITS
5.5
V
0.75
1.0
µA
1.25
VEE 0.2
VCC +
0.2
0.3
V
5
mV
TA = TMIN to TMAX
-0.2V ≤ VCM ≤ (VCC + 0.2V) (Note 3)
TA = +25°C
10
4
0.15
TA = TMIN to TMAX
mV
1
2
nA
Power-Supply Rejection Ratio
PSRR
VCC = 1.8V to 5.5V
0.1
1
mV/V
Common-Mode Rejection Ratio
CMRR
(VEE - 0.2V) ≤ VCM ≤ (VCC + 0.2V)
0.5
3
mV/V
_______________________________________________________________________________________
3
MAX9025–MAX9028
UCSP, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
ELECTRICAL CHARACTERISTICS—MAX9027/MAX9028 (WITHOUT REF) (continued)
(VCC = +5V, VEE = 0V, VCM = 0V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
Output Voltage Swing High
Output Voltage Swing Low
Output Leakage Current
SYMBOL
VCC - VOH
VOL
ILEAK
CONDITIONS
MAX9027 only, VCC =
5V, ISOURCE = 5mA
TA = +25°C
MAX9028 only, VCC =
1.8V, ISOURCE = 1mA
TA = +25°C
VCC = 1.8V,
ISINK = 1mA
TA = +25°C
High-to-Low Propagation Delay
(Note 4)
tPDMAX9027 only
Low-to-High Propagation Delay
(Note 4)
tPD+
MAX9028 only
191
400
500
58
191
mV
400
500
56
TA = TMIN to TMAX
VCC = 5V
200
UNITS
300
TA = TMIN to TMAX
MAX9028 only, VO = 5.5V
Sourcing, VO = VCC
MAX
TA = TMIN to TMAX
TA = +25°C
ISC
TYP
TA = TMIN to TMAX
VCC = 5V,
ISINK = 5mA
Sourcing, VO = VEE
Output Short-Circuit Current
MIN
200
mV
300
0.001
1
µA
35
VCC = 1.8V
3
VCC = 5V
33
VCC = 1.8V
3
VCC = 1.8V
16
VCC = 5V
14
VCC = 1.8V
15
VCC = 5V
40
VCC = 1.8V,
RPULLUP = 100kΩ
16
VCC = 5V,
RPULLUP = 100kΩ
45
mA
µs
µs
Rise Time
tRISE
MAX9027 only, CL = 15pF
1.6
µs
Fall Time
tFALL
CL = 15pF
0.2
µs
1.2
ms
Power-Up Time
tON
Note 1: All specifications are 100% tested at TA = +25°C. 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 MAX9025/MAX9026, reference voltage
error should also be added.
4
_______________________________________________________________________________________
UCSP, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
MAX9027/MAX9028
SUPPLY CURRENT vs. SUPPLY VOLTAGE
TA = +25°C
TA = -40°C
800
TA = +85°C
600
500
TA = +25°C
2.5
1.5
3.5
4.5
4.5
5.5
-40
-15
10
35
60
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
MAX9027/MAX9028
SUPPLY CURRENT vs. TEMPERATURE
MAX9025/MAX9026
SUPPLY CURRENT vs. OUTPUT
TRANSITION FREQUENCY
MAX9027/MAX9028
SUPPLY CURRENT vs. OUTPUT
TRANSITION FREQUENCY
VCC = 3V
VCC = 3V
25
20
15
VCC = 5V
10
400
VCC = 1.8V
-15
10
35
60
85
25
VCC = 3V
20
15
VCC = 5V
5
0
VCC = 1.8V
0
1
0.1
10
100
0.1
1
100
10
TEMPERATURE (°C)
TRANSITION FREQUENCY (kHz)
TRANSITION FREQUENCY (kHz)
OUTPUT VOLTAGE LOW
vs. SINK CURRENT
OUTPUT VOLTAGE LOW
vs. SINK CURRENT
MAX9025/MAX9027
OUTPUT VOLTAGE HIGH vs. SOURCE CURRENT
VCC = 3V
VCC = 1.8V
400
200
VCC = 5V
600
TA = +25°C
400
TA = +85°C
200
TA = -40°C
0
0
2
4
6
SINK CURRENT (mA)
8
10
800
MAX9025-28 toc09
600
800
MAX9025-28 toc08
MAX9025-28 toc07
800
OUTPUT VOLTAGE LOW (mV)
-40
30
10
5
300
35
VCC = 1.8V
85
MAX9025-28 toc06
30
SUPPLY CURRENT (µA)
600
500
35
SUPPLY CURRENT (µA)
VCC = 5V
40
MAX9025-28 toc05
40
MAX9025-28 toc04
700
SUPPLY CURRENT (nA)
3.5
SUPPLY VOLTAGE (V)
800
0
800
600
2.5
1.5
5.5
VCC = 3V
VCC = 1.8V
300
600
VCC = 5V
1000
TA = -40°C
400
OUTPUT VOLTAGE LOW (mV)
MAX9025-28 toc02
700
SUPPLY CURRENT (nA)
1000
1200
OUTPUT VOLTAGE HIGH (VCC - VOH, mV)
SUPPLY CURRENT (nA)
TA = +85°C
800
SUPPLY CURRENT (nA)
MAX9025-28 toc01
1200
MAX9025/MAX9026
SUPPLY CURRENT vs. TEMPERATURE
MAX9025-28 toc03
MAX9025/MAX9026
SUPPLY CURRENT vs. SUPPLY VOLTAGE
600
VCC = 1.8V
VCC = 3V
400
200
VCC = 5V
0
0
2
4
6
SINK CURRENT (mA)
8
10
0
2
4
6
8
10
SOURCE CURRENT (mA)
_______________________________________________________________________________________
5
MAX9025–MAX9028
Typical Operating Characteristics
(VCC = +5V, VEE = 0V, CL = 15pF, VOVERDRIVE = 100mV, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = 0V, CL = 15pF, VOVERDRIVE = 100mV, TA = +25°C, unless otherwise noted.)
TA = +85°C
200
TA = -40°C
TA = +25°C
0
VCC = 5V
20
VCC = 3V
10
VCC = 1.8V
VOUT = VEE
0
4
6
8
10
VCC = 5V
20
VCC = 3V
10
VCC = 1.8V
-15
10
35
60
85
-40
-15
10
35
60
TEMPERATURE (°C)
OFFSET VOLTAGE
vs. TEMPERATURE
HYSTERESIS VOLTAGE
vs. TEMPERATURE
INPUT BIAS CURRENT
vs. INPUT BIAS VOLTAGE
MAX9025-28 toc13
0.8
VCC = 1.8V
VCC = 3V
0.3
4.0
VCC = 3V
VCC = 1.8V
3.5
3.0
VCC = 5V
2.5
1.000
85
MAX9025-28 toc15
TEMPERATURE (°C)
MAX9025-28 toc14
SOURCE CURRENT (mA)
1.0
0.5
30
0
-40
INPUT BIAS CURRENT (IN-) (nA)
2
HYSTERESIS VOLTAGE (mV)
0
OFFSET VOLTAGE (mV)
30
40
SHORT-CIRCUIT SINK CURRENT (mA)
400
VOUT = VCC
MAX9025-28 toc11
600
MAX9025/MAX9027 SHORT-CIRCUIT SOURCE
CURRENT vs. TEMPERATURE
40
SHORT-CIRCUIT SINK CURRENT (mA)
MAX9025-28 toc10
OUTPUT VOLTAGE HIGH (VCC - VOH, mV)
800
SHORT-CIRCUIT SINK
CURRENT vs. TEMPERATURE
MAX9025-28 toc12
MAX9025/MAX9027
OUTPUT VOLTAGE HIGH vs. SOURCE CURRENT
IN+ = 2.5V
0.600
0.200
-0.200
-0.600
VCC = 5V
2.0
0
-40
-15
10
35
60
-15
10
35
60
85
-0.5
0.5
1.5
2.5
3.5
4.5
INPUT BIAS VOLTAGE (IN-) (V)
MAX9025/MAX9026
REFERENCE VOLTAGE vs. TEMPERATURE
MAX9025/MAX9026
REFERENCE VOLTAGE vs. TEMPERATURE
MAX9025/MAX9026
REFERENCE VOLTAGE
vs. SUPPLY VOLTAGE
1.2340
1.237
1.235
1.233
-40
-15
10
35
TEMPERATURE (°C)
60
85
1.237
1.236
1.235
1.234
1.231
1.2330
1.238
5.5
MAX9025-28 toc18
MAX9025-28 toc17
5 DEVICES
REFERENCE VOLTAGE (V)
VCC = 5V
1.2350
1.239
REFERENCE VOLTAGE (V)
VCC = 1.8V
1.2360
MAX9025-28 toc16
TEMPERATURE (°C)
VCC = 3V
6
-1.000
-40
85
TEMPERATURE (°C)
1.2370
REFERENCE VOLTAGE (V)
MAX9025–MAX9028
UCSP, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
-40
-15
10
35
TEMPERATURE (°C)
60
85
1.5
2.5
3.5
SUPPLY VOLTAGE (V)
_______________________________________________________________________________________
4.5
5.5
UCSP, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
MAX9025/MAX9026
REFERENCE VOLTAGE
vs. REFERENCE CURRENT
1.238
VCC = 1.8V
15
40
VCC = 5V
tPD- (µs)
1.236
VCC = 5V
tPD+ (µs)
VCC = 3V
VCC = 1.8V
10
30
VCC = 3V
20
VCC = 5V
1.234
MAX9025-28 toc21
VCC = 3V
50
MAX9025-28 toc20
20
MAX9025-28 toc19
1.240
REFERENCE VOLTAGE (V)
MAX9025/MAX9027
PROPAGATION DELAY (tPD+)
vs. TEMPERATURE
PROPAGATION DELAY (tPD-)
vs. TEMPERATURE
5
10
VCC = 1.8V
1.232
0
-100
-50
0
50
100
0
-40
-15
10
35
85
-15
10
35
60
TEMPERATURE (°C)
PROPAGATION DELAY (tPD-)
vs. CAPACITIVE LOAD
MAX9025/MAX9027
PROPAGATION DELAY (tPD+)
vs. CAPACITIVE LOAD
PROPAGATION DELAY (tPD-)
vs. INPUT OVERDRIVE
30
10
VCC = 3V
20
VCC = 5V
VCC = 1.8V
0
40
VCC = 3V
10
100
VCC = 5V
10
0
0
1
VCC = 1.8V
50
20
10
0.1
60
VCC = 3V
30
5
0.01
70
tPD- (µs)
tPD+ (µs)
VCC = 5V
MAX9025-28 toc24
VCC = 1.8V
0.01
0.1
1
10
100
0
10
20
30
40
CAPACITIVE LOAD (nF)
CAPACITIVE LOAD (nF)
INPUT OVERDRIVE (mV)
MAX9025/MAX9027
PROPAGATION DELAY (tPD+)
vs. INPUT OVERDRIVE
MAX9026/MAX9028
PROPAGATION DELAY (tPD+)
vs. PULLUP RESISTANCE
PROPAGATION DELAY (VCC = 5V)
50
175
150
tPD+ (µs)
VCC = 5V
30
VCC = 3V
50
MAX9025 toc27
MAX9025-28 toc26
200
MAX9025-28 toc25
60
40
85
80
MAX9025-28 toc23
40
MAX9025-28 toc22
15
tPD+ (µs)
-40
TEMPERATURE (°C)
20
tPD- (µs)
60
REFERENCE CURRENT (nA)
+100mV
IN+
-100mV
125
100
75
20
10
VCC = 1.8V
0
OUT
2V/div
50
VCC = 5V
25
VCC = 3V
0V
VCC = 1.8V
0
0
10
20
30
INPUT OVERDRIVE (mV)
40
50
10
100
1000
10000
20µs/div
PULLUP RESISTANCE (kΩ)
_______________________________________________________________________________________
7
MAX9025–MAX9028
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = 0V, CL = 15pF, VOVERDRIVE = 100mV, TA = +25°C, unless otherwise noted.)
MAX9025–MAX9028
UCSP, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = 0V, CL = 15pF, VOVERDRIVE = 100mV, TA = +25°C, unless otherwise noted.)
1kHz FREQUENCY RESPONSE
(VCC = 5V)
PROPAGATION DELAY (VCC = 1.8V)
PROPAGATION DELAY (VCC = 3V)
MAX9025 toc29
MAX9025 toc28
MAX9025 toc30
+100mV
+100mV
IN+
IN+
IN+
-100mV
-100mV
OUT
1V/div
OUT
2V/div
0V
0V
-100mV
OUT
1V/div
0V
20µs/div
20µs/div
10kHz FREQUENCY RESPONSE
(VCC = 1.8V)
REFERENCE RESPONSE TO SUPPLY
VOLTAGE TRANSIENT (CREF = 10nF)
200µs/div
POWER-UP/POWER-DOWN RESPONSE
MAX9025 toc32
MAX9025 toc31
+100mV
MAX9025 toc33
+100mV
REF
200mV/div
IN+
-100mV
VCC
2V/div
5V
VCC
1V/div
OUT
1V/div
0V
OUT
2V/div
1.8V
0V
20µs/div
8
0V
1ms/div
40µs/div
_______________________________________________________________________________________
UCSP, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
VCC
VCC
IN+
IN+
OUT
IN-
OUT
IN-
MAX9027
MAX9028
MAX9025
MAX9026
REF
REF
1.236V
VEE
VEE
Pin Description
PIN
MAX9025/
MAX9026
MAX9027/
MAX9028
NAME
FUNCTION
MAX9026/MAX9028 have an open-drain output stage
that can be pulled beyond VCC to a maximum of 5.5V
above V EE. These open-drain versions are ideal for
implementing wire-OR output logic functions.
Input Stage Circuitry
A2
A2
OUT
Comparator Output
A3
A3, B2
VEE
Negative Supply Voltage
B1
B1
IN+
Comparator Noninverting
Input
B2
—
REF
1.236V Reference Output
A1
A1
VCC
Positive Supply Voltage
B3
B3
IN-
Comparator Inverting
Input
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
Detailed Description
The MAX9025/MAX9026 feature an on-board 1.236V
±1% reference, yet draw an ultra-low supply current of
1.0µA. The MAX9027/MAX9028 (without reference)
consume just 0.6µA 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 MAX9025/MAX9027 have a push-pull
output stage that sinks as well as sources current. The
The MAX9025–MAX9028 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.
_______________________________________________________________________________________
9
MAX9025–MAX9028
Functional Diagrams
MAX9025–MAX9028
UCSP, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
Reference (MAX9025/MAX9026)
VCC
The MAX9025–MAX9028s’ internal +1.236V reference
has a typical temperature coefficient of 40ppm/°C over
the full -40°C to +85°C temperature range. The reference
is a very-low-power bandgap cell, with a typical 35kΩ
output impedance. REF can source and sink up to
100nA to external circuitry. For applications needing
increased drive, buffer REF with a low input-bias current
op amp such as the MAX4162. Most applications require
no REF bypass capacitor. For noisy environments or fast
VCC transients, connect a 1nF to 10nF ceramic capacitor
from REF to GND.
Applications Information
Low-Voltage, Low-Power Operation
The MAX9025–MAX9028 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 MAX9025–MAX9028, assuming nominal
conditions.
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
MAX9025–MAX9028 have internal 4mV 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
REF
BANDGAP
VEE
Figure 1. MAX9025/MAX9026 Voltage Reference Output
Equivalent Circuit
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.
Adding External Hysteresis
In applications requiring more than the internal 4mV
hysteresis of the MAX9025–MAX9028, additional hysteresis can be added with external components.
Because the MAX9025–MAX9028 are intended for very
low-power systems, care should be taken to minimize
power dissipation in the additional circuitry.
Regardless of which approach is taken, the external
hysteresis will be VCC dependent. Over the full discharge
range of battery-powered systems, the hysteresis can
change as much as 40%. This must be considered
during design.
Table 1. Battery Applications Using MAX9025–MAX9028
RECHARGEABLE
VFRESH (V)
VEND-OF-LIFE
(V)
CAPACITY,
AA SIZE
(mA-H)
MAX9025/MAX9026
OPERATING TIME
(hr)
MAX9027/MAX9028
OPERATING TIME
(hr)
Alkaline
(2 Cells)
No
3.0
1.8
2000
1.8 x 106
2.8 x 106
NickelCadmium
(2 Cells)
Yes
2.4
1.8
750
680,000
1.07 x 106
Lithium-Ion
(1 Cell)
Yes
3.5
2.7
1000
0.9 x 106
1.4 x 106
Nickel-MetalHydride
(2 Cells)
Yes
2.4
1.8
1000
0.9 x 106
1.4 x 106
BATTERY
TYPE
10
______________________________________________________________________________________
UCSP, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
RFB
RS
VTHR
VIN
HYSTERESIS
INVHB
VCC
BAND
VTHF
MAX9027
OUT
VCC/2
OUT
Figure 2. Threshold Hysteresis Band
Figure 3. MAX9025/MAX9027 External Hysteresis
Simplest Circuit
The simplest circuit for adding external hysteresis is
shown in Figure 3. In this example, the hysteresis is
defined by:
Asymmetrical Hysteresis
When the input threshold is not set at 1/2 VCC, the hysteresis added to the input threshold will not be symmetrical. This is typical of the MAX9025/MAX9026 where
the internal reference is usually used as the threshold.
If the asymmetry is unacceptable, it can be corrected
by adding resistors to the circuit.
Hysteresis =
RS
× VCC
RFB
where RS is the source resistance and RFB is the feedback resistance. Because the comparison threshold is
1/2 VCC, the MAX9027 was chosen for its push-pull output and lack of reference. This provides symmetrical
hysteresis around the threshold.
Output Considerations
In most cases, the push-pull outputs of the
MAX9025/MAX9027 are best for external hysteresis.
The open-drain output of the MAX9026/MAX9028 can
be used, but the effect of the feedback network on the
actual output high voltage must be considered.
Component Selection
Because the MAX9025–MAX9028 are intended for very
low power-supply systems, the highest impedance circuits should be used wherever possible. The offset
error due to input-bias current is proportional to the
total impedance seen at the input. For example, selecting components for Figure 3, with a target of 50mV hysteresis, a 5V supply, and choosing an RFB of 10MΩ
gives RS as 100kΩ. The total impedance seen at IN+ is
therefore 10MΩ || 100kΩ, or 99kΩ. The maximum IB of
the MAX9025–MAX9028 is 2nA; therefore, the error due
to source impedance is less than 400µV.
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 surfacemount components are recommended. If the REF pin is
decoupled, use a new low-leakage capacitor.
Zero-Crossing Detector
Figure 4 shows a zero-crossing detector application.
The MAX9027’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.
Logic-Level Translator
The Typical Application Circuit shows an application
that converts 5V logic to 3V logic levels. The MAX9028
is powered by the +5V supply voltage, and the pullup
resistor for the MAX9028’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.
______________________________________________________________________________________
11
MAX9025–MAX9028
THRESHOLDS
IN+
MAX9025–MAX9028
UCSP, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
Typical Application Circuit
VCC
+5V (+3V)
VCC
100mVP-P
+3V (+5V)
IN+
OUT
2MΩ
IN-
VCC
RPULLUP
IN-
MAX9027
OUT
2MΩ
VEE
3V (5V)
LOGIC OUT
IN+
MAX9028
Figure 4. Zero-Crossing Detector
UCSP Applications Information
For the latest application details on UCSP construction,
dimensions, tape carrier information, printed circuit board
techniques, bump-pad layout, and recommended reflow
temperature profiles, as well as the latest information on
reliability testing results, go to Maxim’s web site at
www.maxim-ic.com/ucsp to find the Application Note:
UCSP—A Wafer-Level Chip-Scale Package.
12
VEE
5V (3V) LOGIC IN
LOGIC-LEVEL
TRANSLATOR
Chip Information
TRANSISTOR COUNT: 209
PROCESS: BiCMOS
______________________________________________________________________________________
UCSP, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
PACKAGE TYPE
B6+1
OUTLINE NO.
LAND PATTERN NO.
21-0097
Refer to Application Note 1891
6L, UCSP.EPS
6 UCSP
PACKAGE CODE
PACKAGE OUTLINE, 3x2 UCSP
21-0097
G
1
1
______________________________________________________________________________________
13
MAX9025–MAX9028
Package Information
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
MAX9025–MAX9028
UCSP, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
Revision History
REVISION
NUMBER
REVISION
DATE
0
5/04
Initial release.
—
1
6/11
Added information for lead-free versions
1
DESCRIPTION
PAGES
CHANGED
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.
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