19-4429; Rev 1; 1/10
KIT
ATION
EVALU
BLE
AVAILA
Ultra-Precision, High-Side
Current-Sense Amplifiers
Features
♦
Ultra-Precision V
OS
Over Temperature
MAX9922: ±10µV (max)
MAX9923T: ±25µV (max)
MAX9923H: ±20µV (max)
MAX9923F: ±10µV (max)
♦
±0.5% (max) Full-Scale Gain Accuracy
♦
Bidirectional or Unidirectional I
SENSE
♦
Multiple Gains Available
Adjustable (MAX9922)
+25V/V (MAX9923T)
+100V/V (MAX9923H)
+250V/V (MAX9923F)
♦
1.9V to 28V Input Common-Mode Voltage,
Independent of V
DD
♦
Supply Voltage: +2.85V to +5.5V
♦
700µA Supply Current, 1µA Shutdown Current
♦
Extended Temperature Range (-40°C to +85°C)
♦
Available in Space-Saving 10-Pin µMAX
General Description
The MAX9922/MAX9923 ultra-precision, high-side cur-
rent-sense amplifiers feature ultra-low offset voltage
(V
OS
) of 25µV (max) and laser-trimmed gain accuracy
better than 0.5%. The combination of low V
OS
and high-
gain accuracy allows precise current measurements
even at very small sense voltages.
The MAX9922/MAX9923 are capable of both unidirec-
tional and bidirectional operation. For unidirectional
operation, connect REF to GND. For bidirectional oper-
ation, connect REF to V
DD
/2.
The MAX9922 has adjustable gain set with two external
resistors. The MAX9923T/MAX9923H/MAX9923F use an
internal laser-trimmed resistor for fixed gain of 25V/V,
100V/V, and 250V/V, respectively. The devices operate
from a +2.85V to +5.5V single supply, independent
of the input common-mode voltage, and draw only 700µA
operating supply current and less than 1µA in shutdown.
The +1.9V to +28V current-sense input common-mode
voltage range makes the MAX9922/MAX9923 ideal for
current monitoring in applications where high accuracy,
large common-mode measurement range, and mini-
mum full-scale V
SENSE
voltage is critical.
The MAX9922/MAX9923 use a spread-spectrum
autozeroing technique that constantly measures and
cancels the input offset voltage, eliminating drift over
time and temperature, and the effect of 1/f noise. This,
in conjunction with the indirect current-feedback tech-
nique, achieves less than 25µV (max) offset voltage.
The MAX9922/MAX9923 are available in a small 10-pin
µMAX
®
package and are specified over the -40°C to
+85°C extended temperature range.
MAX9922/MAX9923
Ordering Information
PART
MAX9922EUB+
MAX9923TEUB+
MAX9923HEUB+
MAX9923FEUB+
PIN-
PACKAGE
10 µMAX
10 µMAX
10 µMAX
10 µMAX
TEMP
RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
GAIN (V/V)
Adjustable
25
100
250
Applications
Notebook/Desktop Power Management
Handheld Li+ Battery Current Monitoring
Precision Current Sources
+Denotes
a lead(Pb)-free/RoHS-compliant package.
Pin Configuration
TOP VIEW
RSB 1
RS+
2
3
4
5
+
10 V
DD
9
OUT
FB
REF
SHDN
Typical Operating Circuits appear at end of data sheet.
µMAX is a registered trademark of Maxim Integrated Products, Inc.
RS-
N.C.
GND
MAX9922
MAX9923T
MAX9923H
MAX9923F
8
7
6
µMAX
________________________________________________________________
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.
Ultra-Precision, High-Side
Current-Sense Amplifiers
MAX9922/MAX9923
ABSOLUTE MAXIMUM RATINGS
RSB, RS+, RS- to GND...........................................-0.3V to +30V
V
DD
to GND ..............................................................-0.3V to +6V
OUT, REF, FB,
SHDN
to GND .................-0.3V to the lower of (V
DD
+ 0.3V) and +6V
OUT Short Circuit to V
DD
or GND ..............................Continuous
Differential Voltage (V
RS+
- V
RS-
), (V
RSB
- V
RS+
),
(V
RSB
- V
RS-
) ...................................................................±5.5V
Current into Any Pin..........................................................±20mA
Continuous Power Dissipation (T
A
= +70°C)
10-Pin µMAX (derate 4.5mW/°C above +70°C) ...........362mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°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
RSB
= V
RS+
= V
RS-
= +12V, V
DD
= +3.3V, V
GND
= 0V, V
REF
= V
DD
/2 for bidirectional, V
REF
= 0V for unidirectional, V
SENSE
= V
RS+
- V
RS-
= 0V, MAX9922 is set for A
V
=100V/V (R1 = 1kΩ, R2 = 99kΩ),
SHDN
= V
DD
, T
A
= -40°C to +85°C, unless otherwise noted. Typical values
are at T
A
= +25°C.) (Note 1)
PARAMETER
DC CHARACTERISTICS
MAX9922 (A
V
= 100), V
SENSE
= 0V,
V
REF
= V
DD
/2, -40°C
≤
T
A
≤
+85°C
Input Offset Voltage
(Notes 2, 3)
MAX9923T, V
SENSE
= 0V, V
REF
= V
DD
/2,
-40°C
≤
T
A
≤
+85°C
V
OS
MAX9923H, V
SENSE
= 0V, V
REF
= V
DD
/2
-40°C
≤
T
A
≤
+85°C
MAX9923F, V
SENSE
= 0V, V
REF
= V
DD
/2,
-40°C
≤
T
A
≤
+85°C
MAX9922 (A
V
= 100V/V), V
SENSE
= 0V,
V
REF
= V
DD
/2, -40°C
≤
T
A
≤
+85°C
MAX9923T, V
SENSE
= 0V, V
REF
= V
DD
/2,
-40°C
≤
T
A
≤
+85°C
MAX9923H, V
SENSE
= 0V, V
REF
= V
DD
/2,
-40°C
≤
T
A
≤
+85°C
MAX9923F, V
SENSE
= 0V, V
REF
= V
DD
/2,
-40°C
≤
T
A
≤
+85°C
Input Common-Mode Range
Input Common-Mode Rejection
V
CMR
CMRR
Guaranteed by CMRR
1.9V
≤
V
RS+
≤
28V, -40°C
≤
T
A
≤
+85°C
(Note 2)
MAX9922
Gain
A
V
MAX9923T
MAX9923H
MAX9923F
1.90
121
140
Adj
25
100
250
V/V
±0.1
±0.2
±0.2
±0.1
±10
±25
µV
±20
±10
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
±0.05
Input Offset Voltage
Temperature Drift (Notes 2, 4)
±0.20
µV/°C
±0.10
±0.05
28.00
V
dB
TCV
OS
2
_______________________________________________________________________________________
Ultra-Precision, High-Side
Current-Sense Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(V
RSB
= V
RS+
= V
RS-
= +12V, V
DD
= +3.3V, V
GND
= 0V, V
REF
= V
DD
/2 for bidirectional, V
REF
= 0V for unidirectional, V
SENSE
= V
RS+
- V
RS-
= 0V, MAX9922 is set for A
V
=100V/V (R1 = 1kΩ, R2 = 99kΩ),
SHDN
= V
DD
, T
A
= -40°C to +85°C, unless otherwise noted. Typical values
are at T
A
= +25°C.) (Note 1)
PARAMETER
SYMBOL
MAX9922
(A
V
= 100)
Gain Accuracy
(Note 5)
MAX9923T
∆A
V
MAX9923H
MAX9923F
MAX9922 (A
V
= 100)
Gain Nonlinearity
~A
V
MAX9923T
MAX9923H
MAX9923F
MAX9922
MAX9922
MAX9923T/MAX9923H/MAX9923F resistance
between FB and REF
Guaranteed by REF
CMRR test
T
A
= +25°C
-40°C
≤
T
A
≤
+85°C
0
0
94
100
±20
±60
±16
±6
R
L
= 10kΩ to GND
and REF = GND
R
L
= 10kΩ to V
DD
and REF = V
DD
- 1.4
7
1
1
6
0.6 x
V
DD
0.001
±1
±70
±20
±7
30
mV
6
10
30
0.3
mV
V
V
µA
µA
CONDITIONS
T
A
= +25°C
-40°C
≤
T
A
≤
+85°C
T
A
= +25°C
-40°C
≤
T
A
≤
+85°C
T
A
= +25°C
-40°C
≤
T
A
≤
+85°C
T
A
= +25°C
-40°C
≤
T
A
≤
+85°C
±0.06
±0.04
±0.06
±0.12
160
1
1
1
V
DD
-
1.4
V
DD
-
1.6
V
dB
pA
pA
kΩ
%
±0.21
±0.24
±0.12
MIN
TYP
±0.17
MAX
±0.40
±0.60
±0.30
±0.60
±0.40
±0.75
±0.50
±0.80
%
UNITS
MAX9922/MAX9923
Open-Loop Gain
Input Bias Current
FB Bias Current
FB Resistance
A
VOL
I
RS+
, I
RS
-
I
FB
R
FB
REF Input Range
REF Common-Mode Rejection
Ratio
0
≤
REF
≤
V
DD
- 1.4V (Note 2)
MAX9922 (bidirectional)
dB
REF Input Current
(Note 6)
MAX9923T (bidirectional)
MAX9923H (bidirectional)
MAX9923F (bidirectional)
V
OH
= V
DD
– V
OUT
(Note 7)
OUT High Voltage
V
OH
OUT Low Voltage (Note 7)
SHDN
Logic-Low
SHDN
Logic-High
SHDN
Input Current
V
OL
V
IL
V
IH
I
IH
/I
IL
R
L
= 10kΩ to GND and REF = GND
R
L
= 10kΩ to V
DD
and REF = V
DD
- 1.4
V
DD
= 5.5V
V
DD
= 5.5V
_______________________________________________________________________________________
3
Ultra-Precision, High-Side
Current-Sense Amplifiers
MAX9922/MAX9923
ELECTRICAL CHARACTERISTICS (continued)
(V
RSB
= V
RS+
= V
RS-
= +12V, V
DD
= +3.3V, V
GND
= 0V, V
REF
= V
DD
/2 for bidirectional, V
REF
= 0V for unidirectional, V
SENSE
= V
RS+
- V
RS-
= 0V, MAX9922 is set for A
V
=100V/V (R1 = 1kΩ, R2 = 99kΩ),
SHDN
= V
DD
, T
A
= -40°C to +85°C, unless otherwise noted. Typical values
are at T
A
= +25°C.) (Note 1)
PARAMETER
AC CHARACTERISTICS
MAX9922
-3dB Small-Signal Bandwidth
BW
V
SENSE
= 10mV
P-P
V
SENSE
= 5mV
P-P
Slew Rate
OUT Settling Time to 1% of
Final Value
Input-Voltage Noise
Peak-to-Peak
Autozeroing Clock Frequency
Capacitive-Load Stability
POWER-SUPPLY CHARACTERISTICS
Supply Voltage Range
Power-Supply Rejection Ratio
V
DD
PSRR
I
DD
I
RSB
Shutdown Supply Current
Power-Down Input Current
I
DD_SD
I
RSB_SD
I
RS+L
,
I
RS-L
Guaranteed by PSRR
2.85V
≤
V
DD
≤
5.5V, -40°C
≤
T
A
≤
+85°C
(Note 2)
V
DD
= 5.0V
V
DD
= 3.0V
V
RSB
= 12V
V
SHDN
= 0.3V
V
SHDN
= 0.3V, V
RSB
= 28V
V
DD
= V
REF
= 0V, V
RSB
= V
RS+
= V
RS-
= 28V
2.85
93
99
780
700
200
0.05
0.05
0.01
1300
1500
300
1
1
0.1
µA
µA
µA
5.50
V
dB
f
C
SR
MAX9923T
MAX9923H
MAX9923F
MAX9922
C
LOAD
= 7pF
MAX9923T
MAX9923H
MAX9923F
f
O
= 0.1Hz to 10Hz
Pseudo-random
No sustained oscillations
∆V
OUT
= 2V, C
LOAD
= 100pF
10
50
10
2.5
0.4
200
100
200
400
3.4
20
200
µV
P-P
kHz
pF
µs
V/µs
kHz
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Quiescent Supply Current
4
_______________________________________________________________________________________
Ultra-Precision, High-Side
Current-Sense Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(V
RSB
= V
RS+
= V
RS-
= +12V, V
DD
= +3.3V, V
GND
= 0V, V
REF
= V
DD
/2 for bidirectional, V
REF
= 0V for unidirectional, V
SENSE
= V
RS+
- V
RS-
= 0V, MAX9922 is set for A
V
=100V/V (R1 = 1kΩ, R2 = 99kΩ),
SHDN
= V
DD
, T
A
= -40°C to +85°C, unless otherwise noted. Typical values
are at T
A
= +25°C.) (Note 1)
PARAMETER
Power-Down Supply Current
Power-Up Time
SYMBOL
I
RSBL
CONDITIONS
V
DD
= V
REF
= 0V, V
RSB
= V
RS+
= V
RS-
= 28V
MAX9922, A
V
= 100V/V, V
REF
= 0V, V
SENSE
=
10mV, V
DD
= 0V to 3.3V, settling to 0.1% of final
value
MIN
TYP
0.05
800
MAX
1
UNITS
µA
µs
MAX9922/MAX9923
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
All devices are 100% production tested at T
A
= +85°C. All temperature limits are guaranteed by design.
V
OS
is measured in bidirectional mode with V
REF
= V
DD
/2.
Data sheet limits are guaranteed by design and bench characterization. Thermocouple effects preclude measurement of
this parameter during production testing. Devices are screened during production testing to eliminate defective units.
V
OS
drift limits are guaranteed by design and bench characterization and are the average of drift from -40°C to +25°C and
from +25°C to +85°C.
V
RSB
= V
RS+
= 12V, V
REF
= V
DD
/2 for bipolar mode and V
REF
= 0V for unipolar mode. Gain accuracy and gain linearity are
specified over a V
SENSE
range that keeps the output voltage 250mV away from the rails to achieve full accuracy. Output of
the part is rail-to-rail, and goes to within 25mV of the rails, but accuracy is not maintained. Linear operation is not guaran-
teed for V
SENSE
voltages > ±150mV. See the
Typical Operating Characteristics
section for plots of Input vs. Output.
This is the worst-case REF current needed to directly drive the bottom terminal of the gain setting resistors, at V
DD
= 3.3V,
and V
REF
= V
DD
/2 while maintaining gain accuracy. An internal 1kΩ resistor (R1) is present in the MAX9923T/
MAX9923H/MAX9923F between the FB and REF pins, while in the MAX9922 the resistor is external and user selectable. A
voltage identical to the V
SENSE
develops across this resistor. In all versions the REF input current is dependent on the mag-
nitude and polarity of V
SENSE
, and in the MAX9922 it is dependent on the value of the external resistor as well. The input
bias current for REF is typically 1pA in the MAX9922 since it connects to the gate of a MOS transistor. See the
External
Reference
section for more details.
The range of V
REF
, V
CM
, and V
SENSE
may limit the output swing of the MAX9922 with adjustable gain set to less than
100V/V.
_______________________________________________________________________________________
5
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