MAX44286 [MAXIM]
Low-Power, Precision, 4-Bump WLP, Current-Sense Amplifier;型号: | MAX44286 |
厂家: | MAXIM INTEGRATED PRODUCTS |
描述: | Low-Power, Precision, 4-Bump WLP, Current-Sense Amplifier |
文件: | 总11页 (文件大小:715K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
EVALUATION KIT AVAILABLE
MAX44286
Low-Power, Precision, 4-Bump WLP,
Current-Sense Amplifier
General Description
Features and Benefits
● Ultra-Low Input Offset Voltage and Tiny Gain Error
The MAX44286 is a zero-drift, high-side current-sense
amplifier family that offers precision, low supply cur-
rent and is available in a tiny 4-bump ultra-thin WLP of
0.78mm x 0.78mm x 0.35mm footprint. This miniature size
is of paramount for today’s applications in smartphones,
mobile accessories, notebooks, portable medical, and all
battery-operated portable devices where current monitor-
ing with precision and space are critical.
Allow Sense Resistor to Detect Tiny Currents (nA)
•
•
30µV (max) Offset Voltage
0.23% (max) Gain Accuracy
● Low Current Consumption Saves Power
12.5μA I for 200kHz Gain Bandwidth
•
CC
● Space-Saving 4-Bump WLP Package
• 0.78mm x 0.78mm x 0.35mm
The MAX44286 has voltage output offered in four gain
versions of 25V/V, 50V/V, 100V/V, and 200V/V. These
four gain versions offer flexibility in the choice of the
sense resistor and the very low input offset voltage helps
in detecting small currents on the orders of low micro-
amps. Low power capability also offers the possibility of
minimizing power dissipation.
● Industry-Leading Low-Power Supply Range
•
1.6V to 5.5V Input Common Mode
● Four Gain Options Offer Flexibility in Sense Resistor
Selection
•
•
•
•
G = 25V/V (MAX44286T)
G = 50V/V (MAX44286F)
G = 100V/V (MAX44286H)
G = 200V/V (MAX44286W)
The MAX44286 operates with a supply voltage range
of 1.6V to 5.5V over the -40°C to +85°C temperature
range and from 1.8V to 5.5V over the -40°C to +125°C
automotive temperature range. Supply voltage for the
device is shared with the RS+ pin to fit the MAX44286 in
a 4-bump, ultra-thin WLP package.
Typical Application Circuit
I
LOAD
R
SENSE
Applications
● Power Management Systems
● Portable/Battery-Powered Systems
● Smartphones
0.1µF
V
BAT
RS+
A1
RS-
A2
GND
GND
LOAD
GND
R
IN
● Mobile Accessories
● Portable Medical
● Notebook Computers and Tablets
Ordering Information appears at end of data sheet.
V
= 3.3V
DD
For related parts and recommended products to use with this part, refer
P
to www.maximintegrated.com/MAX44286.related.
µC
OUT
B2
MAX1655
ADC
MAX44286
R
B
R
G
R
A
GND B1
GND
19-7369; Rev 0; 11/14
MAX44286
Low-Power, Precision, 4-Bump WLP,
Current-Sense Amplifier
Absolute Maximum Ratings
RS+, RS- to GND....................................................-0.3V to +6V
OUT to GND............................................ -0.3V to (V + +0.3)V
RS+ to RS-..............................................................-0.3V to +6V
Short-Circuit Duration (OUT to Any Other Pins) .......Continuous
Continuous Input Current (Any Pin).................................±20mA
Operating Temperature Range......................... -40°C to +125°C
Junction Temperature......................................................+150°C
Storage Temperature Range............................ -65°C to +150°C
Soldering Temperature (reflow).......................................+260°C
RS
Continuous Power Dissipation (T = +70°C)
A
WLP (derate 9.7mW/°C above +70°C)........................776mW
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.
(Note 1)
Package Thermal Characteristics
WLP
Junction-to-Ambient Thermal Resistance (θ ) ........103°C/W
JA
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer
board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.
Electrical Characteristics
(V
= V
= 3.6V, V
= 0V, T = -40°C to +125°C, unless otherwise noted. Typical values are at T = +25°C.) (Note 2)
RS+
RS-
SENSE
A
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
17
UNITS
T
= +25°C
12.5
A
Supply Current
I
µA
S
-40°C < T < +125°C
A
20
Guaranteed by CMRR,
-40°C < T < +125°C
A
1.8
1.6
5.5
5.5
Common-Mode Input Range
V
V
CM
Guaranteed by CMRR,
-40°C < T < +85°C
A
1.8V < V
V = 10mV
SENSE
< 5.5V,
RS+
120
100
100
Common-Mode Rejection Ratio/
Power-Supply Rejection Ratio
CMRR,
PSRR
dB
1.6V < V
< 5.5V, -40°C < T < +85°C,
A
= 10mV
RS+
120
7
V
SENSE
T
= +25°C
30
50
A
Input Offset Voltage (Note 3)
V
µV
OS
-40°C < T < +125°C
A
Input Offset Voltage Drift
(Note 3)
TCV
40
300
nV/°C
OS
MAX44286T
MAX44286F
MAX44286H
MAX44286W
25
50
Gain
G
V/V
100
200
0.1
T = +25°C
0.23
0.25
1
A
Gain Error (Note 4)
GE
%
-40°C < T < +125°C
A
Input Bias Current RS-
Capacitive Loading
I
0.02
400
30
nA
pF
RS-
C
No sustained oscillations
Sink current = 300µA
Sink current = 0µA
L
65
15
OUT Low Voltage
V
mV
OL
3
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MAX44286
Low-Power, Precision, 4-Bump WLP,
Current-Sense Amplifier
Electrical Characteristics (continued)
(V
= V
= 3.6V, V
= 0V, T = -40°C to +125°C, unless otherwise noted. Typical values are at T = +25°C.) (Note 2)
RS+
RS-
SENSE
A
A
PARAMETER
SYMBOL
CONDITIONS
Source current = 300µA
Source current = 0µA
= 20mV
MIN
TYP
28
MAX
50
UNITS
V
-
RS+
OUT High Voltage
mV
V
1
2
OH
Gain-Bandwidth Product
Slew Rate
GBW
SR
V
200
0.08
66
kHz
V/µs
nV/√Hz
µs
SENSE
∆V
= 2V , C = 100pF
P-P L
OUT
Voltage Noise Density
Output Settling Time
Power-Up Time
V
n
f = 1kHz
0.1% final value, ∆V
t
= 2V
P-P
75
S
OUT
t
350
µs
ON
Note 2: All devices are 100% production tested at T = +25°C. All temperature limits are guaranteed by design.
A
Note 3: Guaranteed by design.
Note 4: Gain Error is calculated by applying two values of V
for each gain:
SENSE
G = 25: V
G = 50: V
= 4mV and 120mV
= 2mV and 60mV
SENSE
SENSE
G = 100: V
G = 200: V
= 1mV and 30mV
= 0.5mV and 15mV
SENSE
SENSE
Typical Operating Characteristics
(V
= V
= 3.6V, V
= 0V, T = +25°C, unless otherwise noted.)
RS+
RS-
SENSE A
INPUT BIAS CURRENT
vs. TEMPERATURE
INPUT OFFSET VOLTAGE
vs. TEMPERATURE
SUPPLY CURRENT
vs. TEMPERATURE
toc02
toc03
toc01
7
6
5
4
3
2
1
0
13.6
110
90
13.4
13.2
13
VCM = 5.5V
VCM = 5.5V
VCM = 3V
VCM = 5.5V
VCM = 3.6V
70
VCM =3V
12.8
12.6
12.4
12.2
12
50
VCM = 1.8V
VCM =1.8V
30
VCM = 1.8V
VCM = 1.6V
10
-10
11.8
-40
-5
30
65
100
135
-40
-5
30
65
100
135
-40
-15
10
35
60
85
110 135
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
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MAX44286
Low-Power, Precision, 4-Bump WLP,
Current-Sense Amplifier
Typical Operating Characteristics (continued)
(V
= V
= 3.6V, V = 0V, T = +25°C, unless otherwise noted.)
SENSE A
RS+
RS-
CMRR
vs. TEMPERATURE
GAIN ERROR
vs. TEMPERATURE
OUTPUT VOLTAGE
vs. INPUT SENSE VOLTAGE
toc04
toc05
toc06
-0.082
128
126
124
122
120
118
116
114
112
2.5
2
VCM = 1.8V
-0.084
-0.086
-0.088
-0.09
1.5
1
G = 25V/V
G = 50V/V
VCM = 1.8V
G = 100V/V
G = 200V/V
0.5
0
-0.092
-0.094
VCM = 5.5V
-40
-5
30
65
100
135
-40
-5
30
65
100
135
0
20
40
60
80
100
TEMPERATURE (°C)
TEMPERATURE (°C)
VSENSE (mV)
OUTPUT VOLTAGE
vs. INPUT SENSE VOLTAGE
INPUT NOISE-VOLTAGE DENSITY
AC RESPONSE
toc08
toc9
toc07
6
5
4
3
2
1
0
50
45
40
35
30
25
20
15
10
5
0.00001
0.000001
0.0000001
1E-08
VCM = 5.5V
66nV/√Hz AT 1kHz
G = 25V/V
G = 50V/V
G = 100V/V
G = 200V/V
0
1E-09
1
100
10000
1000000
0
50
100
150
200
250
1
10
100
1000
10000 100000
VSENSE (mV)
FREQUENCY (Hz)
FREQUENCY (Hz)
POWER-UP TIME
SMALL-SIGNAL RESPONSE (G = 25)
0.1Hz to 10Hz INPUT NOISE
toc11
toc10
toc12
~350µs TO TURN ON
VSENSE
20mVP-P
VOUT
1µV/div
VRS+
VOUT
100µs/div
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MAX44286
Low-Power, Precision, 4-Bump WLP,
Current-Sense Amplifier
Typical Operating Characteristics (continued)
(V
= V
= 3.6V, V
= 0V, T = +25°C, unless otherwise noted.)
RS+
RS-
SENSE A
LARGE-SIGNAL RESPONSE (G = 25)
SMALL-SIGNAL RESPONSE (G = 50)
LARGE-SIGNAL RESPONSE (G = 50)
toc13
toc14
toc15
VSENSE
100mVP-P
VSENSE
50mVP-P
VSENSE
10mVP-P
VOUT
VOUT
VOUT
SMALL-SIGNAL RESPONSE (G = 100)
LARGE-SIGNAL RESPONSE (G = 100)
toc17
toc16
VSENSE
VSENSE
5mVP-P
20mVP-P
VOUT
VOUT
SMALL-SIGNAL RESPONSE (G = 200)
LARGE-SIGNAL RESPONSE (G = 200)
toc18
toc19
VSENSE
2.5mVP-P
VSENSE
10mVP-P
VOUT
2VP-P
VOUT
0.5VP-P
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MAX44286
Low-Power, Precision, 4-Bump WLP,
Current-Sense Amplifier
Pin Configuration
TOP VIEW
MAX44286
+
RS+
A1
B1
A2
B2
RS-
GND
OUT
WLP
Pin Description
BUMP
A1
NAME
RS+
FUNCTION
Power-Side Connection to External Sense Resistor
A2
RS-
Load-Side Connection to External Sense Resistor
B1
GND
OUT
Ground
Output
B2
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MAX44286
Low-Power, Precision, 4-Bump WLP,
Current-Sense Amplifier
Functional Diagram
RS+
A1
RS-
A2
R
IN
P
B2 OUT
R
B
R
G
R
A
MAX44286
GND B1
Table 1. Internal Gain-Setting Resistors (Typical Values)
PART
MAX44286T
MAX44286F
MAX44286H
MAX44286W
GAIN(V/V)
R
(kΩ)
R
(kΩ)
R
(kΩ)
R (kΩ)
B
IN
G
A
25
50
10
50
100
400
10
10
10
50
50
50
50
25
450
475
100
200
12.5
487.5
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MAX44286
Low-Power, Precision, 4-Bump WLP,
Current-Sense Amplifier
OUT Swing vs. V
and V
SENSE
Detailed Description
RS+
The MAX44286 is unique because the supply voltage is
the input common-mode voltage (the average voltage at
RS+ and RS-). There is no separate V
input. Therefore, the OUT voltage swing is limited by the
minimum voltage at RS+.
The MAX44286 unidirectional high-side, current-sense
amplifier family implements a unique autozeroing tech-
nique to minimize the input offset voltage with close to
zero offset drift over time and temperature. This technique
achieves 7µV (max) input offset voltage.
supply voltage
CC
V
= V
- V
- V
OH
The MAX44286 operates with the same supply and input
common-mode voltage range from 1.6V to 5.5V without
a need for an extra supply voltage terminal. This feature
allows direct current monitoring of a battery voltage as low
as +1.6V, and the part consumes only 12µA (typ) through
the RS+ input when there is no differential input voltage
applied.
OUT(MAX)
RS+(MIN)
SENSE(FS)
and:
R
= V
/(Gain x I
)
SENSE
OUT(MAX)
LOAD(MAX)
Accuracy
In the linear region (V
components to accuracy: input offset voltage (V ) and
< V
), there are two
OUT(MAX)
OUT
OS
gain error (GE). For the MAX44286, V
= 7µV (max)
The MAX44286 has an internal architecture that forces
OS
and gain error is 0.15% (max). To calculate the total error,
use the linear equation:
current through internal gain resistor R depending on
the magnitude of sense voltage drop across sense resis-
tor. Due to the effect of negative feedback, the voltage
IN
V
OUT
= (Gain ± GE) x V
± (gain x V )
OS
SENSE
drop across R is the same as the voltage drop across
IN
A high R
value allows lower currents to be mea-
SENSE
the sense resistor R
. The current through R is
SENSE
IN
sured more accurately because offsets are less significant
when the sense voltage is larger. For extremely low input
offset voltage and gain error that this part offers, this out-
put voltage error is insignificant.
the same as the current through R . The voltage across
G
R
is then amplified through the gain-setting resistor R
G
A
and feedback resistor R . The output voltage can be cal-
B
culated based on the following equation:
Full-Scale Sense Voltage Range V
SENSE(FS)
The gain error of the MAX44286 is production tested and
guaranteed with V = 3.6V over a V range as
R
R
R
R
G
B
V
= V
×
× 1+
OUT
SENSE
IN
A
DD
SENSE
shown in Note 4 of the Electrical Characteristics table. It
Applications Information
is important to note that a higher V range can be
SENSE
obtained if a higher V
supply is available.
Power Supply, Bypassing, and Layout
DD
Good layout technique optimizes performance by
decreasing the amount of stray capacitance at the high-
side, current-sense-amplifier, common-mode inputs and
output. Capacitive decoupling across the battery volt-
age to GND of 0.1µF is recommended as shown in the
Typical Application Circuit. Since the MAX44286 features
ultra-low input offset voltage, board leakage, and ther-
mocouple effects can easily introduce errors in the input
offset voltage readings when used with high-impedance
signal sources. For noisy digital environments, the use of
a multilayer PCB with separate ground and power-supply
planes is recommended. Keep digital signals far away
from the sensitive analog common mode inputs.
The following equation applies:
= (V
V
- 0.6)/Gain
DD
SENSE(FS)
For example, using the MAX44286F (for which G=50) at
a V = 5.5V:
DD
V
= (5.5 - 0.6)/50 = 98mV
SENSE(FS)
(i.e. full-scale linear range as measured on the sense resistor)
Efficiency and Power Dissipation
At high current levels, the I2R losses in R
significant. Consider this when choosing the resistor value
and its power dissipation (wattage) rating. Also, the sense
resistor value might drift if it is allowed to heat up exces-
can be
SENSE
sively. The precision V
of MAX44286 allows to sense
OS
Choosing the Sense Resistor
very low current using small sense resistors that reduce
power dissipation and reduce hot spots. Dynamic range
of the current that can be sensed is improved with low
Choose R
based on the following criteria:
SENSE
Voltage Loss
A high R
V
and low sense resistors.
OS
value causes the power-source voltage
SENSE
to drop due to IR loss. For minimal voltage loss, use the
lowest R value.
SENSE
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MAX44286
Low-Power, Precision, 4-Bump WLP,
Current-Sense Amplifier
Kelvin Connections
Bidirectional Application
Because of the high currents that flow through R
,
Battery-powered systems may require a precise bidirec-
tional current-sense amplifier to accurately monitor the
battery’s charge and discharge currents. Measurements
of the two MAX44286 separate outputs with respect to
GND yield an accurate measure of the charge and dis-
charge currents (Figure 1).
SENSE
take care to eliminate 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. This is very important lay-
out practice for any ultra-precision current-sense ampli-
fiers. As shown in the Typical Application Circuit, para-
sitic trace resistance is eliminated by measuring the drop
across sense resistor right across its terminals.
Optional Output Filter Capacitor
When designing a system that uses a sample-and-hold
stage in the ADC, the sampling capacitor momentarily
loads OUT and causes a drop in the output voltage. If
sampling time is very short (less than a microsecond),
consider using a ceramic capacitor across OUT and
GND to hold V
constant during sampling. This also
OUT
decreases the small-signal bandwidth of the current-
sense amplifier and reduces noise at OUT.
ICHARGE
ILOAD
RSENSE
D1
TO WALL/CUBE-
CHARGER
LOAD
0.1µF
V
RS+ A1 A2 RS-
RS+ A1 A2 RS-
GND
GND
GND
RIN
RIN
MAX44286
MAX44286
P
P
OUT
B2
OUT
B2
VDD = 3.3V
R
R
B
B
R
G
R
G
CH1
CH2
MAX11190
ADC
R
R
A
A
µC
GND
B1
GND
B1
GND
GND
Figure 1. Bidirectional Application
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MAX44286
Low-Power, Precision, 4-Bump WLP,
Current-Sense Amplifier
Ordering Information
Package Information
For the latest package outline information and land patterns
(footprints), go to www.maximintegrated.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.
TEMP
RANGE
PIN-
GAIN
PART
PACKAGE (V/V)
MAX44286TAZS+
MAX44286FAZS+
MAX44286HAZS+
MAX44286WAZS+
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
4 WLP
4 WLP
4 WLP
4 WLP
25
50
100
200
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
+Denotes a lead(Pb)-free/RoHS-compliant package.
Refer to
Application Note
1891
4 WLP
Z40A0+1
21-0683
Chip Information
PROCESS: CMOS
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MAX44286
Low-Power, Precision, 4-Bump WLP,
Current-Sense Amplifier
Revision History
REVISION REVISION
PAGES
CHANGED
DESCRIPTION
NUMBER
DATE
0
11/14
Initial release
—
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
©
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
2014 Maxim Integrated Products, Inc.
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