EVALUATION KIT AVAILABLE
MAX9934
High-Precision, Low-Voltage, Current-Sense Amplifier
with Current Output and Chip Select for Multiplexing
General Description
The MAX9934 high-precision, low-voltage, high-side
current-sense amplifier is ideal for both bidirectional
(charge/discharge) and unidirectional current measure-
ments in battery-powered portable and laptop devices.
Input offset voltage (V
OS
) is a low 10µV (max) at +25°C
across the -0.1V to 5.5V input common-mode voltage
range, and is independent of V
CC
. Its precision input
specification allows the use of very small sense volt-
ages (typically ±10mV full-scale) for minimally invasive
current sensing.
The output of the MAX9934 is a current proportional to
input V
SENSE
and is available in either 25µA/mV or
5µA/mV gain options (G
M
) with gain accuracy better
than 0.25% (max) at +25°C. A chip select (CS) allows
multiplexing of several MAX9934 current outputs to a
single microcontroller ADC channel (see the
Typical
Operating Circuit).
CS is compatible with 1.8V and 3.3V
logic systems.
The MAX9934 is designed to operate from a 2.5V to
3.6V V
CC
supply, and draws just 120µA (typ) quiescent
current. When powered down (V
CC
= 0), RS+ and RS-
draw less than 0.1nA (typ) leakage current to reduce
battery load. The MAX9934 is robust and protected
from input faults of up to ±6V input differential voltage
between RS+ and RS-.
The MAX9934 is specified for operation over the -40°C
to +125°C temperature range and is available in an
8-pin µMAX
®
or a 6-bump UCSP™ (1mm x 1.5mm x
0.6mm), making it ideal for space-sensitive applications.
o
Input Offset Voltage: 10µV (max)
o
Gain Error Less than 0.25%
o
-0.1V to +5.5V Input Common-Mode Voltage
Range
o
Chip Select Allows Multiplexing Several MAX9934
Current Monitors to One ADC
o
Current Output Allows R
OUT
Selection
for Gain Flexibility
o
Single Supply Operation: 2.5V to 3.6V
o
Two Gain Options: G
M
of 25µA/mV (MAX9934T)
and 5µA/mV (MAX9934F)
o
Bidirectional or Unidirectional Operation
o
Small, 6-Bump UCSP (1mm x 1.5mm x 0.6mm)
and 8-Pin
µMAX
Packages
Features
Ordering Information
PART
MAX9934FART+T
MAX9934FAUA+T
MAX9934FAUA/V+T
MAX9934TART+T
MAX9934TAUA+T
MAX9934TAUA/V+T
GAIN
5µA/mV
5µA/mV
5µA/mV
25µA/mV
25µA/mV
25µA/mV
PIN-
PACKAGE
6 UCSP
8 µMAX
8 µMAX
6 UCSP
8 µMAX
8 µMAX
TOP
MARK
AAG
—
AAG
AAF
—
AAF
Applications
PDAs and Smartphones
MP3 Players
Sensor Instrumentation Amplifiers
Notebook PCs and Ultra-Mobile PCs
Portable Current Monitoring
Note:
All devices are specified over the -40°C to +125°C
extended temperature range.
+Denotes
a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
Typical Operating Circuit
V
CC
= 3.3V
0.1µF
-0.1V
≤
V
CM
≤
5.5V
I
LOAD
R
SENSE
V
CC
MAX9934
RS-
OUT
V
OUT
TO ADC
RS+
R
OUT
10kΩ
GND
CS
FROM
µC
CHIP SELECT
1000pF
µMAX is a registered trademark and UCSP is a trademark of
Maxim Integrated Products, Inc.
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-5011; Rev 3; 11/12
MAX9934
High-Precision, Low-Voltage, Current-Sense Amplifier
with Current Output and Chip Select for Multiplexing
ABSOLUTE MAXIMUM RATINGS
RS+, RS- to GND......................................................-0.3V to +6V
V
CC
to GND ..............................................................-0.3V to +4V
CS, OUT to GND (V
CC
= 0, or CS < V
IL
)..................-0.3V to +4V
OUT to GND (CS > V
IH
)................................-0.3V to V
CC
+ 0.3V
Differential Input Voltage (RS+ - RS-) ....................................±6V
Output Short-Circuit Current Duration
OUT to GND or V
CC
...............................................Continuous
Continuous Input Current into Any Terminal.....................±20mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin µMAX (derate multilayer 4.8mW/°C
above +70°C).............................................................388mW
Junction-to-Ambient Thermal Resistance (θ
JA
)
(Note 1) ....................................................................206°C/W
Junction-to-Case Thermal Resistance (θ
JC
)
(Note 1) ......................................................................42°C/W
6-Bump UCSP (derate multilayer 3.9mW/°C
above +70°C).............................................................308mW
Junction-to-Ambient Thermal Resistance (θ
JA
)
(Note 1) ....................................................................260°C/W
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (µMAX only, soldering, 10s) ..............+300°C
Soldering Temperature (reflow) .......................................+260°C
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.
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
CC
= 3.3V, V
RS+
= V
RS-
= 3.0V, V
SENSE
= 0V, V
CM
= (V
RS+
+ V
RS-
)/2, V
CS
= 3.3V, R
OUT
= 10kΩ to GND for unidirectional opera-
tion, R
OUT
= 10kΩ to V
CC
/2 for bidirectional operation. T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
=
+25°C.) (Note 2)
PARAMETER
DC CHARACTERISTICS
MAX9934T
Input Offset Voltage (Note 3)
V
OS
MAX9934F
Input Offset Voltage Drift (Note 3)
Common-Mode Input Voltage
Range (Average of V
RS
+ and
V
RS
-) (Note 3)
V
OS
/dT
MAX9934T
MAX9934F
Guaranteed by CMRR2
0
≤
V
CM
≤
V
CC
-
0.2V (MAX9934F)
CMRR1
Common-Mode Rejection Ratio
(Note 3)
CMRR2
0
≤
V
CM
≤
V
CC
-
0.2V (MAX9934T)
-0.1
≤
V
CM
≤
5.5V
(MAX9934F)
-0.1
≤
V
CM
≤
5.5V
(MAX9934T)
T
A
= +25°C
-40°C
≤
T
A
≤
+125°C
T
A
= +25°C
-40°C
≤
T
A
≤
+125°C
T
A
= +25°C
-40°C
≤
T
A
≤
+125°C
T
A
= +25°C
-40°C
≤
T
A
≤
+125°C
-0.1
128
112
128
109
119
104
98
98
113
125
135
dB
134
T
A
= +25°C
-40°C
≤
T
A
≤
+125°C
T
A
= +25°C
-40°C
≤
T
A
≤
+125°C
±10
±14
±10
±20
±60
±90
+5.5
nV/°C
µV
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
CMVR
V
2
Maxim Integrated
MAX9934
High-Precision, Low-Voltage, Current-Sense Amplifier
with Current Output and Chip Select for Multiplexing
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 3.3V, V
RS+
= V
RS-
= 3.0V, V
SENSE
= 0V, V
CM
= (V
RS+
+ V
RS-
)/2, V
CS
= 3.3V, R
OUT
= 10kΩ to GND for unidirectional opera-
tion, R
OUT
= 10kΩ to V
CC
/2 for bidirectional operation. T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
=
+25°C.) (Note 2)
PARAMETER
Current Gain (Transconductance)
SYMBOL
G
M
MAX9934T
MAX9934F
MAX9934T
Current Gain Error
(Note 4)
G
ME
MAX9934F
Gain Error Drift
Input-Bias Current for RS+
Input-Bias Current for RS-
Input Leakage Current
DC CHARACTERISTICS
Minimum Current for Output Low
Output-Voltage Range
(MAX9934T)
Output-Voltage Range
(MAX9934F)
Deselected Amplifier Output
Leakage
LOGIC I/O (CS)
Input Voltage Low CS
Input Voltage High CS
Input Current CS
POWER SUPPLY
Supply-Voltage Range
Power-Supply Rejection Ratio
Supply Current
Supply Current, Output
Deselected
V
CC
PSRR
I
CC
I
CC,DES
Guaranteed by PSRR
2.5V
≤
V
CC
≤
3.6V,
V
RS+
= V
RS-
= 2V (Note 3)
V
CC
= 3.3V, R
OUT
= 10kΩ to 3.3V,
V
RS+
= V
RS-
= 3.1V
V
CS
= 0V, R
OUT
= 10kΩ to 3.3V,
V
RS+
= V
RS-
= 3.1V
MAX9934T
G
M
= 25µA/mV, V
SENSE
= 5mV
MAX9934F
G
M
= 5µA/mV, V
SENSE
= 25mV
2.5
110
120
120
120
230
210
3.6
V
dB
µA
µA
V
IL
V
IH
I
IL
,I
IH
0
≤
V
CS
≤
V
CC
0.1
0.54
1.26
100
V
V
nA
I
OL
V
OH
V
OL
V
OH
V
OL
I
OLK
Unidirectional, V
OL
= I
OL
x R
OUT
I
OUT
= +600µA, V
OH
= V
CC
- V
OUT
I
OUT
= -600µA, bidirectional
I
OUT
= +375µA, V
OH
= V
CC
- V
OUT
I
OUT
= -375µA, bidirectional
V
CS
= 0V, V
OUT
= 3.6V,
and 0
≤
V
CC
≤
3.6V
1
0.1
0.15
0.18
0.18
0.1
100
0.25
0.25
0.30
0.26
100
nA
V
V
nA
G
ME
/dT
I
BRS+
I
BRS-
I
LEK
MAX9934T
MAX9934F
V
RS
+ = V
RS
- = 5.5V
V
RS
+ = V
RS
-
≤
V
CC
- 0.2V
V
RS
+ = V
RS
- = 5.5V
V
CC
= 0V, V
RS+
= V
RS
- = 5.5V
0.1
0.1
35
0.1
T
A
= +25°C
-40°C
≤
T
A
≤
+125°C
T
A
= +25°C
-40°C
≤
T
A
≤
+125°C
CONDITIONS
MIN
TYP
25
5
±0.25
±2.0
±0.25
±2.4
±200
±240
100
100
60
100
ppm/°C
nA
nA
µA
nA
%
MAX
UNITS
µA/mV
AC CHARACTERISTICS (C
L
= 1000pF)
1.5
kHz
5
Amplifier Bandwidth
BW
Maxim Integrated
3
MAX9934
High-Precision, Low-Voltage, Current-Sense Amplifier
with Current Output and Chip Select for Multiplexing
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 3.3V, V
RS+
= V
RS-
= 3.0V, V
SENSE
= 0V, V
CM
= (V
RS+
+ V
RS-
)/2, V
CS
= 3.3V, R
OUT
= 10kΩ to GND for unidirectional opera-
tion, R
OUT
= 10kΩ to V
CC
/2 for bidirectional operation. T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
=
+25°C.) (Note 2)
PARAMETER
Output Settling Time
SYMBOL
t
S
CONDITIONS
0.1% final value, Figure 1, MAX9934T
0.1% final value, Figure 1, MAX9934F
Output to 0.1% final value, Figure 2,
MAX9934T
Output Select Time
t
ZH
Output to 0.1% final value, Figure 2,
MAX9934F
Output step of 100mV, C
L
= 10pF,
Figure 2
Output step of -100mV, C
L
= 10pF,
V
CC
> 2.5V
0.1% final value, Figure 3, MAX9934T
0.1% final value, Figure 3, MAX9934F
MIN
TYP
670
220
150
µs
80
2
2
300
200
µs
µs
µs
MAX
UNITS
µs
Output Deselect Time
Power-Down Time
Power-Up Time
t
HZ
t
PD
t
PU
Note 2:
All devices are 100% production tested at T
A
= +25°C. Unless otherwise noted, specifications overtemperature are guaran-
teed by design.
Note 3:
Guaranteed by design. Thermocouple, contact resistance, RS- input-bias current, and leakage effects preclude measure-
ment of this parameter during production testing. Devices are screened during production testing to eliminate defective
units.
Note 4:
Gain error tested in unidirectional mode: 0.2V
≤
V
OUT
≤
3.1V for the MAX9934T; 0.25V
≤
V
OUT
≤
2.5V for the MAX9934F.
4
Maxim Integrated
MAX9934
High-Precision, Low-Voltage, Current-Sense Amplifier
with Current Output and Chip Select for Multiplexing
Typical Operating Characteristics
(V
CC
= 3.3V, V
RS+
= V
RS-
= 3.0V, V
SENSE
= 0V, C
L
= 1000pF, R
OUT
= 10kΩ to GND for unidirectional operation, R
OUT
= 10kΩ to
V
CC
/2 for bidirectional operation. T
A
= +25°C, unless otherwise noted.)
OFFSET VOLTAGE
vs. COMMON-MODE VOLTAGE
MAX9934 toc02
MAX9934T V
OS
HISTOGRAM
MAX9934 toc01
MAX9934T DRIFT V
OS
HISTOGRAM
30
25
20
N (%)
15
10
5
0
10
8
6
OFFSET VOLTAGE (FV)
4
2
0
-2
-4
-6
-8
-10
0
6
12 18 24 30 36 42 48 54 60
TCV
OS
(nV/NC)
35
30
25
N (%)
20
15
10
5
0
-10 -8
-6
-4
-2
0
2
4
6
8
T
A
= +125NC
T
A
= +25NC
T
A
= -40NC
10
-0.1 0.6
1.3
2.0
2.7
3.4
4.1
4.8
5.5
V
OS
(FV)
COMMON-MODE VOLTAGE (V)
OFFSET VOLTAGE
vs. COMMON-MODE VOLTAGE
8
6
OFFSET VOLTAGE (FV)
4
2
0
-2
-4
-6
-8
-10
-0.1 0.6
1.3
2.0
2.7
3.4
4.1
4.8
5.5
COMMON-MODE VOLTAGE (V)
0
-0.20
-0.16
MAX9934 toc04
MAX9934T GAIN ERROR
HISTOGRAM
MAX9934 toc05
MAX9934T GAIN ERROR
DRIFT HISTOGRAM
MAX9934 toc06
10
30
25
20
N (%)
35
30
25
N (%)
20
15
V
CC
= 2.5V
V
CC
= 3.3V
V
CC
= 3.6V
15
10
5
10
5
0
-0.12
-0.08
-0.04
0.04
0.08
0.12
0
0.16
0.20
-200
-160
-120
-80
-40
0
40
80
120
160
GE (%)
TC GE (PPM/NC)
MAX9934F GAIN ERROR
HISTOGRAM
MAX9934 toc07
MAX9934F GAIN ERROR DRIFT
HISTOGRAM
MAX9934 toc08
V
OUT
vs. V
SENSE
V
REF
= GND
MAX9934 toc09
40
35
30
25
N (%)
25
3.5
3.0
2.5
V
OUT
(V)
GAIN = 25µA/mV
20
N (%)
15
2.0
1.5
1.0
20
15
10
5
-0.20
-0.16
-0.12
-0.08
-0.04
0
0.04
0.08
0.12
0.16
0.20
GAIN = 5µA/mV
10
5
0.5
0
-200
-160
-120
-80
-40
0
40
80
120
160
200
TC GE (PPM/°C)
0
0
10
20
UNIDIRECTIONAL
0
30
40
50
60
70
GE (%)
V
SENSE
(mV)
Maxim Integrated
200
80
MAX9934 toc03
40
5
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