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PDF MAX44284 Data sheet ( Hoja de datos )
| Número de pieza | MAX44284 | |
| Descripción | Low-Power Current-Sense Amplifier | |
| Fabricantes | Maxim Integrated Products | |
| Logotipo |  |
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MAX44284
36V, Input Common-Mode, High-Precision,
Low-Power Current-Sense Amplifier
General Description
The MAX44284 is a high-side, current-sense amplifier
that operates with a 1.7V to 5.5V single supply and is
optimized for very low power operation with only 21µA of
quiescent current.
The MAX44284 offers precision accuracy specifications
of 2μV VOS and gain error of 0.05%. The device features
an input common-mode voltage range from -0.1V to
+36V. This current-sense amplifier has a voltage output
and is offered in four different gain versions.
The MAX44284 is offered in small 6-bump, 0.4mm-pitch
WLP (1.3mm x 0.9mm) and 6-pin SOT23 packages and is
specified for operation over the -40°C to +125°C automo-
tive temperature range.
Applications
● Smartphones and Tablets
● Notebook Computers
● DC-DC Current Sensing in Power Management
● Portable-/Battery-Powered Systems
● Medical Pulse Oximeters and Infusion Pumps
● Base-Stations
Benefits and Features
● Very Low 2μV Input Offset Voltage (MAX44284F/H))
● Extremely Low 50nV/°C Input Offset Temperature
Coefficient
● Low Supply Current of 21μA
● Low 0.05% Gain Error
● -0.1V to +36V Wide Input Common-Mode Range
● Shutdown Input (Independent of VDD)
● Four Gain Options:
• 50V/V – MAX44284F
• 100V/V – MAX44284H
• 200V/V – MAX44284W
• 500V/V – MAX44284E
● Tiny 1.3mm x 0.9mm 6-Bump WLP Package and
6-Pin SOT23 Package
Ordering Information appears at end of data sheet.
For related parts and recommended products to use with this part, refer
to www.maximintegrated.com/MAX44284.related.
Typical Application Circuit
VBATT = UP TO 36V
ILOAD
RSENSE
RS+ RS-
LOAD
VDD = 3.3V
OUT MAX44284
VDD = 3.3V
µC
ADC
19-6862; Rev 2; 6/14
1 page  
MAX44284
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
36V, Input Common-Mode, High-Precision,
Low-Power Current-Sense Amplifier
SUPPLY CURRENT
vs. TEMPERATURE
toc01a
29 GAIN = 50V/V
VDD = 3.3V
27
VDD = 5.5V
25
23
21
19 VDD = 1.7V
17
-50 -25
0 25 50 75 100 125
TEMPERATURE (°C)
SUPPLY CURRENT
vs. TEMPERATURE
34
GAIN = 100V/V
32
VDD = 5.5V
30
28 VDD = 3.3V
toc01b
26
24
VDD = 1.7V
22
20
-50
-25 0 25 50 75
TEMPERATURE (°C)
100 125
SUPPLY CURRENT
vs. TEMPERATURE
25
GAIN = 200V/V
24
VDD = 5.5V
23
toc01c
22
VDD = 3.3V
21
20
19
18
17
-50 -25
VDD = 1.7V
0 25 50 75 100 125
TEMPERATURE (°C)
SUPPLY CURRENT
vs. TEMPERATURE
32
31 GAIN = 500V/V
toc01d
30
29 VDD = 5.5V
28
27 VDD = 3.3V
26
25
24
VDD = 1.7V
23
22
-50 -25
0 25 50 75 100 125
TEMPERATURE (°C)
SUPPLY CURRENT
vs. COMMON VOLTAGE
30
29 VDD = 3.3V
28
27
26 TA = -40ºC
25
24 TA = +125ºC
23
22
21
20
-1
TA = +85ºC TA = +25ºC
4 9 14 19 24 29
VCM (V)
34
GAIN ERROR HISTOGRAM
18
HISTOGRAM
toc03
ALL GAIN
16 OPTIONS
14
12
10
8
6
4
2
0
-0.08 -0.06 -0.04 -0.02 0 0.02 0.04 0.06 0.08
GAIN ERROR (%)
INPUT OFFSET VOLTAGE HISTOGRAM
30
HISTOGRAM
toc04a
GAIN = 50V/V
GAIN = 100V/V
25
20
15
10
5
0
-6
-4 -2 0 2 4
INPUT OFFSET VOLTAGE (μV )
6
INPUT OFFSET VOLTAGE HISTOGRAM
16
HISTOGRAM
14 GAIN = 200V/V
toc04b
12
10
8
6
4
2
0
-20-18-16-14-12-10 -8 -6 -4 -2 0 2 4 6 8 10 12 14 16 18 20
INPUT OFFSET VOLTAGE ( μV )
www.maximintegrated.com
Maxim Integrated │ 5
5 Page 
MAX44284
36V, Input Common-Mode, High-Precision,
Low-Power Current-Sense Amplifier
A high RSENSE value allows lower currents to be mea-
sured more accurately because offsets are less significant
when the sense voltage is larger. Note that the toler-
ance and temperature coefficient of the chosen resistors
directly affect the precision of any measurement sys-
tem. For best performance, select RSENSE to provide
approximately maximum input differential sense voltage of
110mV (MAX44284F) or 55mV (MAX44284H) or 27.5mV
(MAX44284W) or 11mV (MAX44284E) of sense voltage for
the full-scale current in each application. Sense resistors of
5mΩ to 100mΩ are available with 1% accuracy or better.
Efficiency and Power Dissipation
At high current levels, the I2R losses in RSENSE can be
significant. This should be taken into consideration when
choosing the resistor value and its power dissipation
(wattage) rating. The sense resistor’s value will drift if it
is allowed to heat up excessively. The precision VOS of
the MAX44284 allows the use of small sense resistors to
reduce power dissipation and reduce hot spots.
Kelvin Connections
Because of the high currents that may flow through
RSENSE based on the application, take care to eliminate
solder and parasitic trace resistance from causing errors
in the sense voltage. Either use a four-terminal current-
sense resistor or use Kelvin (force and sense) PCB layout
techniques.
Input Filtering
Some applications of current-sense amplifiers need to
measure currents accurately even in the presence of both
differential and common-mode ripple, as well as a wide
variety of input transient conditions.
The MAX44284 allows two methods of filtering to help
improve performance in the presence of input common-
mode voltage and input differential voltage transients.
Figure 1 shows a differential input filter. The capacitor
CIN across RS+ and RS- along with the resistor RIN helps
filter against input differential voltages and prevents them
from reaching the MAX44284. The corner frequency of
this filter is determined by the choice of RIN, CIN. Figure 2
shows a common-mode input filter. The choice of capaci-
tance depends on corner frequency after RIN is chosen.
In case of mismatch or error in application design, an
RSENSE
RIN RIN LOAD
CIN CIN
RS+ RS-
MAX44284
OUT
GND
Figure 1. Differential Input Filtering
RSENSE
RIN RIN LOAD
CIN
RS+ RS-
MAX44284
OUT
GND
Figure 2. Input Common-Mode Filtering
additional DC error is accumulated as offset voltage and
increased gain error.
VOS =(RIN × IOFFSET) + (DRIN × IBIAS)
DRIN is the resistance mismatch in RIN at RS+ and RS-.
If DRIN is too small, its effect can be neglected. Since
IOFFSET of the MAX44284 is smaller than 2nA, and if we
want to make sure VOS is lesser than 1µV range, choosing
RIN < (VOS ÷ IOFFSET)
www.maximintegrated.com
Maxim Integrated │ 11
11 Page | ||
| Páginas | Total 14 Páginas | |
| PDF Descargar | [ Datasheet MAX44284.PDF ] | |
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