19-4251; Rev 3; 4/12
KIT
ATION
EVALU
E
BL
AVAILA
-0.1V to +28V Input Range, Micropower,
Uni-/Bidirectional, Current-Sense Amplifiers
General Description
The MAX9928/MAX9929 low-cost, uni-/bidirectional,
high-side, current-sense amplifiers are ideal for moni-
toring battery charge and discharge currents in note-
books, cell phones, and other portable equipment.
These devices feature a wide -0.1V to +28V input com-
mon-mode voltage range, low 20µA supply current with
V
OS
less than 0.4mV, and a gain accuracy better than
1.0%. The input common-mode range is independent
of the supply voltage, ensuring that the current-sense
information remains accurate even when the measure-
ment rail is shorted to ground.
The MAX9928F features a current output with a transcon-
ductance ratio of 5µA/mV. An external resistor converts
the output current to a voltage, allowing adjustable gain
so that the input sense voltage can be matched to the
maximum ADC input swing. The MAX9929F has a voltage
output and integrates a 10kΩ output resistor for a fixed
voltage gain of 50V/V.
A digital SIGN output indicates direction of current flow,
so the user can utilize the full ADC input range for mea-
suring both charging and discharging currents.
The MAX9928/MAX9929 are fully specified over the -40°C
to +125°C automotive temperature range, and available
in 6-bump UCSP™ (1mm x 1.5mm) and 8-pin µMAX
®
packages. The UCSP package is bump-to-bump com-
patible with the MAX4372_EBT.
UCSP is a trademark and µMAX is a registered trademark of
Maxim Integrated Products, Inc.
Pin Configurations and Typical Operating Circuit appear at
end of data sheet.
Features
o
Wide -0.1V to +28V Common-Mode Range,
Independent of Supply Voltage
o
2.5V to 5.5V Operating Supply Voltage
o
20µA Quiescent Supply Current
o
0.4mV (max) Input Offset Voltage
o
Gain Accuracy Better than 1% (max)
o
SIGN Output Indicates Current Polarity
o
Transconductance and Gain Versions Available
5µA/mV (MAX9928F)
50V/V (MAX9929F)
o
Pin Compatible with the MAX4372 in UCSP
o
Available in Ultra-Small, 3x2 UCSP
(1mm x 1.5mm) and 8-Pin
µMAX
Packages
MAX9928/MAX9929
Applications
Monitoring Charge/Discharge Currents in
Portable/Battery-Powered Systems
Notebook Computers
General-System/Board-Level Current Monitoring
Smart-Battery Packs/Chargers
Precision Current Sources
Smart Cell Phones
Super Capacitor Charge/Discharge
Ordering Information
PART
MAX9928FAUA+
MAX9928FABT+T
MAX9929FAUA+
MAX9929FABT+T
OUTPUT TYPE
Current
Current
Voltage
Voltage
GAIN
G
m
= 5µA/mV
G
m
= 5µA/mV
A
V
= 50V/V
A
V
= 50V/V
PIN-PACKAGE
8 µMAX
3x2 UCSP
8 µMAX
3x2 UCSP
TOP MARK
—
+AAF
—
+ADI
Note:
All devices are specified over the -40°C to +125°C operating temperature range.
+Denotes
a lead-free/RoHS-compliant package.
T = Tape and reel.
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
-0.1V to +28V Input Range, Micropower,
Uni-/Bidirectional, Current-Sense Amplifiers
MAX9928/MAX9929
ABSOLUTE MAXIMUM RATINGS
V
CC
, SIGN to GND ...................................................-0.3V to +6V
RS+, RS- to GND....................................................-0.3V to +30V
OUT to GND ...............................................-0.3V to (V
CC
+ 0.3V)
Differential Input Voltage (V
RS+
- V
RS-
) .............................. ±30V
OUT, SIGN Short Circuit to V
CC
or GND ...................Continuous
Current into Any Pin..........................................................±20mA
Continuous Power Dissipation (T
A
= +70°C)
6-Bump 1mm x 1.5mm UCSP
(derate 3.9mW/°C above +70°C) ............................308.3mW
8-Pin µMAX (derate 4.8mW/°C above +70°C) .............388mW
Operating Temperature Range ........................-40°C to +125°C
Storage Temperature Range ............................-65°C to +150°C
Junction Temperature .....................................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°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
RS+
= -0.1V to +28V, V
CC
= 3.3V, V
SENSE
= (V
RS+
- V
RS-
) = 0V, R
OUT
= 10kΩ for MAX9928F, T
A
= -40°C to +125°C, unless other-
wise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
T
A
= +25°C
T
A
= -40°C to +125°C
T
A
= +25°C
T
A
= -40°C to +125°C
-0.1
T
A
= +25°C
T
A
= -40°C to +125°C
T
A
= +25°C
T
A
= -40°C to +125°C
93
87
60
54
±50
50
T
A
= +25°C
T
A
= -40°C to +125°C
T
A
= +25°C
T
A
= -40°C to +125°C
T
A
= +25°C
T
A
= -40°C to +125°C
T
A
= +25°C
T
A
= -40°C to +125°C
0
-80
±0.05
±0.2
0.05
1.6
5
±0.3
±0.3
±0.3
±0.3
±1.0
±2.5
±1.0
±2.8
µA/mV
±1.0
±2.5
±1.0
±2.8
6
+6
±1
±2
1.0
µA
µA
µA
%
mV
V/V
72
104
dB
±0.6
MIN
TYP
±0.1
MAX
±0.4
±0.8
±1.0
±3.0
+28
V
mV
UNITS
AMPLIFIER DC ELECTRICAL CHARACTERISTICS
V
RS+
= 3.6V
Input Offset Voltage (Note 2)
V
OS
V
RS+
= -0.1V
Common-Mode Input Range
V
CMR
(Note 3)
2V
≤
V
RS+
≤
28V
Common-Mode Rejection Ratio
CMRR
-0.1V
≤
V
RS+
≤
+2V
MAX992_F
MAX9929F
MAX9929F,
V
RS+
= 3.6V
MAX9929F,
V
RS+
= -0.1V
Transconductance (Note 2)
Transconductance Accuracy
(Note 2)
G
M
MAX9928F
MAX9928F,
V
RS+
= 3.6V
MAX9928F,
V
RS+
= -0.1V
I
RS+
, I
RS-
I
OS
I
RS+
, I
RS-
2V
≤
V
RS+
≤
28V
-0.1V
≤
V
RS+
≤
+2V
2V
≤
V
RS+
≤
28V
-0.1V
≤
V
RS+
≤
+2V
V
CC
= 0V, V
RS+
= V
RS-
= 28V (Note 5)
Full-Scale Sense Voltage (Note 2)
Gain (Note 2)
V
SENSE
A
V
Gain Accuracy (Notes 2, 6)
%
Input Bias Current (Note 4)
Input Offset Bias Current (Note 4)
Input Leakage Current
2
_______________________________________________________________________________________
-0.1V to +28V Input Range, Micropower,
Uni-/Bidirectional, Current-Sense Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(V
RS+
= -0.1V to +28V, V
CC
= 3.3V, V
SENSE
= (V
RS+
- V
RS-
) = 0V, R
OUT
= 10kΩ for MAX9928F, T
A
= -40°C to +125°C, unless other-
wise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Output Resistance
SYMBOL
R
OUT
MAX9928F
MAX9929F
MAX9928F, R
OUT
= 10kΩ
Output High Voltage (Note 6)
V
OH
MAX9929F
Minimum Output Voltage (Note 7)
Minimum Output Current (Note 7)
V
OL
I
OL
MAX9929F
MAX9928F
T
A
= +25°C
T
A
= -40°C to +125°C
T
A
= +25°C
T
A
= -40°C to +125°C
T
A
= +25°C
T
A
= -40°C to +125°C
T
A
= +25°C
T
A
= -40°C to +125°C
T
A
= +25°C
T
A
= +25°C
T
A
= +25°C
-0.1
2V
≤
V
RS+
≤
28V
-0.1V
≤
V
RS+
≤
+2V
I
SINK
= 100µA
102
74
0.03
(V
CC
-
0.01)
1
T
A
= +25°C
T
A
= -40°C to +125°C
V
RS+
= 3.6V
V
RS+
= -0.1V
V
RS+
= 3.6V
V
RS+
= -0.1V
2V
≤
V
RS+
≤
28V
-0.1V
≤
V
RS+
< +2V
2.5
2.8
72
66
90
86
90
86
20
115
30
200
5.5
5.5
0.1
(V
CC
-
0.04)
-1.6
-2.15
-2.5
-4.6
-1.8
-1.8
0.6
+28
-1.2
-1.2
6.4
CONDITIONS
MIN
TYP
5
10
(V
CC
-
0.1)
(V
CC
-
0.1)
0.25
0.025
13.6
(V
CC
-
0.45)
V
(V
CC
-
0.45)
2.0
15
0.2
1.5
-0.5
-0.15
+0.25
+2.3
mV
mV
V
dB
V
V
MΩ
mV
µA
MAX
UNITS
MΩ
kΩ
MAX9928/MAX9929
SIGN COMPARATOR DC ELECTRICAL CHARACTERISTICS
Discharge to Charge Trip Point
(Note 8)
Charge to Discharge Trip Point
(Note 8)
Hysteresis Width
Common-Mode Input Range
(Note 9)
Common-Mode Rejection Ratio
(Note 9)
Output Low Voltage
Output High Voltage
Internal Pullup Resistor
POWER SUPPLY
Supply Voltage Range (Note 10)
Amplifier Power-Supply Rejection
Ratio (Note 10)
Comparator Power-Supply
Rejection Ratio
Quiescent Supply Current
V
CC
PSRR
A
PSRR
C
I
CC
V
dB
dB
µA
V
RS+
= 3.6V
V
TDC
V
RS+
= -0.1V
V
TCD
V
HYS
V
CMR
CMRR
V
OL
V
OH
R
PULL-UP
V
RS+
= 3.6V
V
RS+
= -0.1V
V
RS+
= 3.6V,
-0.1V
mV
_______________________________________________________________________________________
3
-0.1V to +28V Input Range, Micropower,
Uni-/Bidirectional, Current-Sense Amplifiers
MAX9928/MAX9929
ELECTRICAL CHARACTERISTICS (continued)
(V
RS+
= -0.1V to +28V, V
CC
= 3.3V, V
SENSE
= (V
RS+
- V
RS-
) = 0V, R
OUT
= 10kΩ for MAX9928F, T
A
= -40°C to +125°C, unless other-
wise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
-3dB Bandwidth
SYMBOL
BW
CONDITIONS
MAX992_F, V
SENSE
= 50mV
V
RS+
= 3.6V,
C
LOAD
= 10pF,
R
OUT
= 10kΩ for
MAX9928F
Overdrive = 1mV
Overdrive = 5mV
Overdrive = 1mV
Overdrive = 5mV
V
SENSE
= 50mV for MAX992_F,
V
RS+
= 3.6V, C
LOAD
= 10pF
100mV
≤
V
SENSE
≤
50mV for MAX992_F,
V
RS+
= 3.6V, C
LOAD
= 10pF
MAX992_F, V
SENSE
=
5mV to 50mV step
MAX992_F, V
SENSE
=
50mV to 5mV step
MIN
TYP
150
6
µs
15
80
30
50
13
50
4
µs
µs
µs
ms
MAX
UNITS
kHz
AC ELECTRICAL CHARACTERISTICS
OUT Settling to 1% of Final Value
t
SET
SIGN Comparator Propagation
Delay (Low to High)
SIGN Comparator Propagation
Delay (High to Low)
Power-Up Time to 1% of Final
Value
Saturation Recovery Time
t
PROP_LH
t
PROP_HL
Note 1:
All devices are 100% production tested at T
A
= +25°C. All temperature limits are guaranteed by design.
Note 2:
V
OS
is extrapolated from two point transconductance and gain accuracy tests. Measurements are made at V
SENSE
=
+5mV and V
SENSE
= +50mV for MAX992_F. These measurements are also used to test the full-scale sense voltage,
transconductance, and gain. These V
OS
specifications are for the trimmed direction only (V
RS+
> V
RS-
). For current flowing
in the opposite direction (V
RS-
> V
RS+
), V
OS
is ±1mV (max) at +25°C and ±1.8mV (max) over temperature, when V
RS+
is at
3.6V. See the
Detailed Description
for more information.
Note 3:
Guaranteed by common-mode rejection ratio. Extrapolated V
OS
as described in Note 2 is used to calculate common-mode
rejection ratio.
Note 4:
Includes input bias current of SIGN comparator.
Note 5:
Leakage in to RS+ or RS- when V
CC
= 0V. Includes input leakage current of SIGN comparator. This specification does not
add to the bias current.
Note 6:
Output voltage should be 650mV below V
CC
to achieve full accuracy.
Note 7:
I
OL
is the minimum output current in the V
SENSE
- I
OUT
transfer characteristics. V
OL
is the minimum output voltage in the
V
SENSE
- V
OUT
transfer characteristic.
Note 8:
V
SENSE
voltage required to switch comparator.
Note 9:
Discharge to charge trip point is functionally tested at V
CM
= -0.1V, +3.6V, and +28V.
Note 10:
Guaranteed by PSRR test. Extrapolated V
OS
as described in Note 2 is used to calculate the power-supply rejection ratio.
V
SENSE
has to be such that the output voltage is 650mV below V
CC
to achieve full accuracy.
4
_______________________________________________________________________________________
-0.1V to +28V Input Range, Micropower,
Uni-/Bidirectional, Current-Sense Amplifiers
Typical Operating Characteristics
(V
CC
= 3.3V, V
RS+
= 12V, T
A
= +25°C, unless otherwise noted.)
GAIN ACCURACY
HISTOGRAM
MAX9928 toc01
MAX9928/MAX9929
V
OS
HISTOGRAM
45
40
35
FREQUENCY (%)
30
25
20
15
10
5
0
-0.40 -0.30 -0.20 -0.10 0
0.10
0.20 0.30 0.40
5
0
A
V
= 50V/V
30
A
V
= 50V/V
25
FREQUENCY (%)
20
15
10
OFFSET VOLTAGE
vs. COMMON-MODE VOLTAGE
MAX9928 toc02
1.5
OFFSET VOLTAGE (mV)
1.0
0.5
0
-0.5
-1.0
-1.5
-2.0
-1
0
1
2
3
28
-1.0 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1.0
GAIN ACCURACY (%)
COMMON-MODE VOLTAGE (V)
V
OS
(mV)
OFFSET VOLTAGE vs. TEMPERATURE
MAX9928 toc04
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX9928 toc05
SUPPLY CURRENT
vs. COMMON-MODE VOLTAGE
MAX9928 toc06
1.0
0.8
0.6
OFFSET VOLTAGE (mV)
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1.0
V
CM
= 3.6V
150
V
SENSE
= 0V
125
SUPPLY CURRENT (μA)
100
75
50
V
RS+
= 3.6V
25
0
2.5
3.0
3.5
4.0
4.5
5.0
V
RS+
= 0V
150
120
SUPPLY CURRENT (μA)
90
V
CC
= 5.5V
60
V
CC
= 2.5V
30
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
0
5.5
-0.5
0
0.5
1.0
1.5
2.0
28
SUPPLY VOLTAGE (V)
COMMON-MODE VOLTAGE (V)
SUPPLY CURRENT
vs. TEMPERATURE
V
SENSE
= 0V
125
SUPPLY CURRENT (μA)
100
75
50
V
RS+
= 3.6V
25
0
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
V
RS+
= 0V
MAX9928 toc07
INPUT BIAS CURRENT
vs. COMMON-MODE VOLTAGE
0
INPUT BIAS CURRENT (μA)
-10
-20
-30
-40
-50
-60
-70
-80
-2
-0.1
0
2
4
6
8
10
28
MAX9928 toc08
150
10
COMMON-MODE VOLTAGE (V)
_______________________________________________________________________________________
MAX9928 toc03
2.0
5
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