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PDF MAX9025 Data sheet ( Hoja de datos )
| Número de pieza | MAX9025 | |
| Descripción | (MAX9025 - MAX9028) Beyond-the-Rails Comparators With/Without Reference | |
| Fabricantes | Maxim Integrated Products | |
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19-3241; Rev 0; 5/04
UCSP, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
General Description
The MAX9025–MAX9028 nanopower comparators in
space-saving chip-scale (UCSP™) packages feature
Beyond-the-Rails™ inputs and are guaranteed to oper-
ate 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 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 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 suit-
able 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
Mobile Communications
Notebooks and PDAs
Sensing at Ground or Supply Line
Telemetry and Remote Systems
Medical Instruments
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
MAX9025EBT-T
MAX9026EBT-T
MAX9027EBT-T
MAX9028EBT-T
TEMP
RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
BUMP-
PACKAGE
6 UCSP-6
6 UCSP-6
6 UCSP-6
6 UCSP-6
TOP
MARK
ADB
ADC
ADD
ADE
Pin Configurations
TOP VIEW
(BUMPS ON BOTTOM)
B
A
1 IN+
VCC
Selector Guide
PART
MAX9025
MAX9026
MAX9027
MAX9028
INTERNAL
REFERENCE
OUTPUT
TYPE
Yes Push-Pull
Yes Open-Drain
No Push-Pull
No Open-Drain
SUPPLY
CURRENT
(µA)
1.0
1.0
0.6
0.6
Typical Application Circuit appears at end of data sheet.
MAX9025–
MAX9028
2
REF
(VEE)
OUT
3 IN-
VEE
Beyond-the-Rails and UCSP are trademarks of Maxim Integrated
Products, Inc.
( ) MAX9027/MAX9028 PINS
UCSP
________________________________________________________________ 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.
1 page  
UCSP, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
Typical Operating Characteristics
(VCC = +5V, VEE = 0V, CL = 15pF, VOVERDRIVE = 100mV, TA = +25°C, unless otherwise noted.)
MAX9025/MAX9026
SUPPLY CURRENT vs. SUPPLY VOLTAGE
1200
TA = +85°C
1000
TA = +25°C
TA = -40°C
800
600
1.5
2.5 3.5 4.5
SUPPLY VOLTAGE (V)
5.5
MAX9027/MAX9028
SUPPLY CURRENT vs. TEMPERATURE
800
700
VCC = 5V
600
VCC = 3V
500
400
300
-40
800
VCC = 1.8V
-15 10 35 60
TEMPERATURE (°C)
OUTPUT VOLTAGE LOW
vs. SINK CURRENT
85
MAX9027/MAX9028
SUPPLY CURRENT vs. SUPPLY VOLTAGE
800
700
TA = +85°C
600
500
TA = +25°C
400 TA = -40°C
300
1.5
2.5 3.5 4.5
SUPPLY VOLTAGE (V)
5.5
MAX9025/MAX9026
SUPPLY CURRENT vs. OUTPUT
TRANSITION FREQUENCY
40
35
30
25 VCC = 3V
20
15
VCC = 5V
10
VCC = 1.8V
5
0
0.1
1 10
TRANSITION FREQUENCY (kHz)
100
OUTPUT VOLTAGE LOW
vs. SINK CURRENT
800
MAX9025/MAX9026
SUPPLY CURRENT vs. TEMPERATURE
1200
VCC = 5V
1000
VCC = 3V
800
VCC = 1.8V
600
-40
-15 10 35 60
TEMPERATURE (°C)
85
MAX9027/MAX9028
SUPPLY CURRENT vs. OUTPUT
TRANSITION FREQUENCY
40
35
30
25 VCC = 3V
20
15
10 VCC = 5V
5
0
0.1
VCC = 1.8V
1 10
TRANSITION FREQUENCY (kHz)
100
MAX9025/MAX9027
OUTPUT VOLTAGE HIGH vs. SOURCE CURRENT
800
600
VCC = 1.8V
400
VCC = 3V
600
TA = +25°C
400
TA = +85°C
600
VCC = 1.8V VCC = 3V
400
200
0
0
VCC = 5V
200
TA = -40°C
200
VCC = 5V
2468
SINK CURRENT (mA)
10
0
0 2 4 6 8 10
SINK CURRENT (mA)
0
0 2 4 6 8 10
SOURCE CURRENT (mA)
_______________________________________________________________________________________ 5
5 Page 
UCSP, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
IN+
VTHR
IN-
VTHF
VHB
THRESHOLDS
HYSTERESIS
BAND
OUT
RS
VIN
VCC/2
RFB
VCC
MAX9027
OUT
Figure 2. Threshold Hysteresis Band
Simplest Circuit
The simplest circuit for adding external hysteresis is
shown in Figure 3. In this example, the hysteresis is
defined by:
Hysteresis =
RS
RFB
× VCC
where RS is the source resistance and RFB is the feed-
back resistance. Because the comparison threshold is
1/2 VCC, the MAX9027 was chosen for its push-pull out-
put 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 cir-
cuits 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, select-
ing components for Figure 3, with a target of 50mV hys-
teresis, 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.
Figure 3. MAX9025/MAX9027 External Hysteresis
Asymmetrical Hysteresis
When the input threshold is not set at 1/2 VCC, the hys-
teresis added to the input threshold will not be symmet-
rical. 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.
Board Layout and Bypassing
Power-supply bypass capacitors are not typically need-
ed, 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.
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 con-
nected to the +3V supply voltage. This configuration
allows the full 5V logic swing without creating overvolt-
age 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
11 Page | ||
| Páginas | Total 13 Páginas | |
| PDF Descargar | [ Datasheet MAX9025.PDF ] | |
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