MAX9918ASA/V+ [MAXIM]
-20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers; -20V至+ 75V输入范围，高精度单向/双向电流检测放大器
| 型号： | MAX9918ASA/V+ |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | -20V to +75V Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers |
| 文件： | 总18页 (文件大小：2383K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-5015; Rev 4; 7/11
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
81/MAX920
General Description
Features
o -20V to +75V Input Common-Mode Voltage Range
o 400µV (max) Input Offset Voltage
o 0.6% (max) Gain Accuracy Error
The MAX9918/MAX9919/MAX9920 are single-supply,
high-accuracy current-sense amplifiers with a high
input common-mode range that extends from -20V to
+75V. These amplifiers are well suited for current moni-
toring of inductive loads such as motors and solenoids,
where common-mode voltages can become negative
due to inductive kickback, reverse-battery conditions,
or transient events.
o Uni- or Bidirectional Current Sensing
o Reference Input for Bidirectional OUT
o 120kHz, -3dB Bandwidth (MAX9919N)
o Single-Supply Operation (4.5V to 5.5V)
o 1mA Supply Current
The MAX9918/MAX9920 feature adjustable gain set by
an external resistive-divider network. The MAX9919 fea-
tures fixed gains of 45V/V (MAX9919F) and 90V/V
(MAX9919N). The MAX9918/MAX9919/MAX9920 oper-
o 0.5µA (typ) Shutdown Current
o Rail-to-Rail Output
ate as unidirectional amplifiers when V
= GND
CC
REFIN
and as bidirectional amplifiers when V
= V /2.
o -40°C to +125°C Automotive Temperature Range
REFIN
The MAX9920 attenuates the input signal by a factor of
4 at the input level-shifting stage allowing the device to
sense voltages up to 200mV (unidirectional operation)
or 100mV (bidirectional operation).
Ordering Information/
Selector Guide
V
GAIN
(V/V)
PIN-
PACKAGE
SENSE
(mV)
The MAX9918/MAX9919/MAX9920 operate with a sin-
gle 5V supply voltage, are fully specified over the -40°C
to +125°C automotive temperature range, and are
available in an 8-pin SOIC package.
PART
MAX9918ASA+
MAX9918ASA/V+
MAX9919FASA+
MAX9919NASA+
MAX9919NASA/V+
MAX9920ASA+
MAX9920ASA/V+
50
50
Adjustable 8 SOIC-EP*
Adjustable 8 SOIC-EP*
Applications
H-Bridge Motor Current Sensing
Solenoid Current Sensing
50
45
90
90
8 SOIC-EP*
8 SOIC-EP*
8 SOIC-EP*
50
50
200
200
Adjustable 8 SOIC-EP*
Adjustable 8 SOIC-EP*
Current Monitoring of Inductive Loads
High- and Low-Side Precision Current Sensing
4x4 Transmission Control
Note: All devices operate over the -40°C to +125°C temperature
range.
+Denotes a lead(Pb)-free/RoHS-compliant package.
/V denotes an automotive qualified part.
*EP = Exposed pad.
Electronic Throttle Control
Super-Capacitor Charge/Discharge Monitoring in
Hybrid Cars
Precision High-Voltage Current Monitoring
Typical Operating Circuit
V
V
CC
CC
V
BATT
OUT
FB
φ2B
φ1A
MAX9918
MAX9920
A
ADC
R
SENSE
R2
R1
M
RS+
INPUT STAGE
LEVEL SHIFTER
RS-
REFIN
REF
ADJUSTABLE GAIN
μC
φ1B
φ2B
SHDN
GND
GND
________________________________________________________________ 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.
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
ABSOLUTE MAXIMUM RATINGS
CC
V
to GND..............................................................-0.3V to +6V
Output Short Circuit to V
or GND...........................Continuous
CC
RS+, RS- to GND (V
RS+, RS- to GND (V
Differential Input Voltage (V
= 5V) ..................................-30V to +80V
= 0V) .............-15V to +80V (15 minutes)
Continuous Current into Any Pin
(Not to exceed package power dissipation) ................ 20mA
Continuous Power Dissipation (T = +70°C)
CC
CC
- V
)
RS+
RS-
A
(MAX9918/MAX9919)................................. 15V (Continuous)
Differential Input Voltage
8-Pin SOIC-EP (derate 24.4mW/°C above +70°C) .1951.2mW**
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°C
(V
- V ) (MAX9920) ............................. 5V (Continuous)
RS-
RS+
REFIN, FB, OUT to GND.............................-0.3V to (V
+ 0.3V)
CC
SHDN to GND.........................................................-0.3V to +20V
**As per JEDEC51 Standard (multilayer board).
PACKAGE THERMAL CHARACTERISTICS (Note 1)
SOIC-EP
Junction-to-Ambient Thermal Resistance (θ ) ...........41°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.maxim-ic.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
= 5V, V
= V
= +14V, V
= (V
- V ) = 0V, V
= V
= 0V, V
= V /2, R = 100kΩ; for MAX9918, A =
REFIN CC L V
CC
RS+
RS-
SENSE
RS+
RS-
SHDN
GND
A
90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, A = 20V/V, R2/R1 = 79kΩ/1kΩ; T = -40°C to +125°C, unless otherwise noted. Typical val-
V
ues are at T = +25°C.) (Note 1)
A
81/MAX920
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
T
T
= +25°C
= -40°C
0.14
0.4
A
A
V
= V
=
RS-
RS+
+14V, V
= 0V
REFIN
0.7
0.4
1.3
0.4
0.9
0.4
1.0
1.2
3.0
0.9
3.5
to +125°C
MAX9918
MAX9919_
MAX9920
T
= +25°C
0.08
0.18
0.11
0.48
0.10
A
V
= V
REFIN
=
RS-
RS+
-2V, V
0V
=
T
= -40°C
A
to +125°C
T
= +25°C
A
V
= V
=
RS-
RS+
+14V, V
= 0V
REFIN
T
= -40°C
A
to +125°C
Input Offset Voltage (Note 2)
V
mV
OS
T
= +25°C
A
V
= V
REFIN
=
RS-
RS+
-2V, V
0V
=
T
= -40°C
A
to +125°C
T
= +25°C
A
V
= V
REFIN
=
RS-
RS+
+14V, V
= 0V
T
= -40°C
A
to +125°C
T
= +25°C
A
V
= V
=
RS-
RS+
-2V, V
0V
=
REFIN
T
= -40°C
A
to +125°C
2
_______________________________________________________________________________________
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
81/MAX920
ELECTRICAL CHARACTERISTICS (continued)
(V
= 5V, V
= V
= +14V, V
= (V
- V ) = 0V, V
= V
= 0V, V
= V /2, R = 100kΩ; for MAX9918, A =
REFIN CC L V
CC
RS+
RS-
SENSE
RS+
RS-
SHDN
GND
A
90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, A = 20V/V, R2/R1 = 79kΩ/1kΩ; T = -40°C to +125°C, unless otherwise noted. Typical val-
V
ues are at T = +25°C.) (Note 1)
A
PARAMETERS
SYMBOL
CONDITIONS
MIN
TYP
1.2
3.3
1.8
1.8
2.4
8.8
MAX
UNITS
V
V
V
V
V
V
= V
= V
= V
= V
= V
= V
= +14V
= -2V
RS+
RS+
RS+
RS+
RS+
RS+
RS-
RS-
RS-
RS-
RS-
RS-
MAX9918
MAX9919_
MAX9920
= +14V
= -2V
Input Offset Voltage Drift
(Note 3)
V
μV/°C
OSD
= +14V
= -2V
Common-Mode Range
V
Inferred from CMRR tests
-20
80
96
72
86
+75
V
CM
-2V ≤ V
≤ +14V
CM
MAX9918, MAX9919
MAX9920
-20V ≤ V
≤ +75V
CM
Common-Mode Rejection Ratio
(Note 3)
CMRR
dB
-2V ≤ V
≤ +14V
CM
-20V ≤ V
≤ +75V
CM
T
T
= +25°C
175
250
8
A
A
Input Bias Current
Input Offset Current
I
, I
-20V ≤ V
≤ +75V
μA
μA
μA
RS+ RS-
CM
= -40°C to +125°C
(I
- I
)
0
RS+ RS-
Input Leakage Current in
Shutdown
-20V ≤ V
≤ +75V, V
= V = 5V
30
30
CM
SHDN
CC
Input Leakage Current
V
= V
= +14V, +75V, V = 0V
RS- CC
μA
kΩ
Ω
RS+
Common mode
Differential
300
715
330
224
50
MAX9918,
MAX9919_
Input Resistance
Common mode
Differential
kΩ
Ω
MAX9920
MAX9918, MAX9919_
MAX9920
Inferred from gain
error test
Full-Scale Sense Voltage (Note 4)
Gain (Notes 2, 4)
V
mV
V/V
V/V
SENSE
G
200
Adj
45
MAX9918, MAX9920
MAX9919F
MAX9919N
90
MAX9918
30
Minimum Adjustable Gain
G
ADJ
MAX9920
7.5
_______________________________________________________________________________________
3
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(V
= 5V, V
= V
= +14V, V
= (V
- V ) = 0V, V
= V
= 0V, V
= V /2, R = 100kΩ; for MAX9918, A =
REFIN CC L V
CC
RS+
RS-
SENSE
RS+
RS-
SHDN
GND
A
90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, A = 20V/V, R2/R1 = 79kΩ/1kΩ; T = -40°C to +125°C, unless otherwise noted. Typical val-
V
ues are at T = +25°C.) (Note 1)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
T
V
= +25°C,
A
0.08
0.6
= 0V
REFIN
V
+14V
= V
=
RS+
RS-
T
= -40°C to
A
+125°C,
= 0V
1.2
MAX9918
V
REFIN
T
T
= +25°C
0.02
0.13
0.10
0.16
0.11
0.29
0.24
0.6
1.0
0.45
1.2
0.45
0.9
0.6
1.2
0.6
1.0
V
= V
REFIN
=
=
A
RS+
RS-
-2V, V
0V
= -40°C to
A
+125°C
T
T
= +25°C
V
= V
REFIN
=
RS-
A
RS+
+14V, V
0V
=
= -40°C to
A
+125°C
MAX9919F
MAX9919N
MAX9920
T
= +25°C
V
= V
=
RS-
A
RS+
-2V, V
0V
=
REFIN
T
A
= -40°C to
Gain Error
(Note 2)
GE
%
+125°C
T
= +25°C
V
= V
=
RS-
A
RS+
+14V, V
0V
=
REFIN
T
= -40°C to
A
+125°C
T
= +25°C
V
= V
REFIN
=
RS-
A
RS+
-2V, V
0V
=
T
A
= -40°C to
+125°C
81/MAX920
T
T
= +25°C
1.0
1.7
1.0
1.7
15
V
= V
REFIN
=
RS-
A
RS+
+14V, V
0V
=
= -40°C to
A
+125°C
T
= +25°C
V
= V
=
RS-
A
RS+
-2V, V
0V
=
REFIN
T
A
= -40°C to
+125°C
FB Input Bias Current
I
MAX9918, MAX9920
= 200mV for
MAX9918, MAX9919_,
= 400mV for
MAX9920
= -200mV for
MAX9918, MAX9919_,
= -400mV for
5
3
nA
FB
V
SENSE
R = 100kΩ to GND
10
L
Output-Voltage High (Note 4)
V
- V
mV
CC
OH
V
SENSE
R = 10kΩ to GND
12
3
40
10
40
L
V
SENSE
R = 100kΩ to V
L
CC
Output-Voltage Low (Note 4)
V
mV
OL
V
SENSE
R = 10kΩ to V
10
L
CC
MAX9920
OUT shorted to V
44
41
CC
Short-Circuit Current
Output Resistance
I
mA
SC
OUT shorted to GND
R
0.1
Ω
OUT
V
/2
V
1.9
-
-
CC
CC
MAX9918, MAX9919_
MAX9920
0
0
Inferred from REFIN
CMRR test
REFIN Voltage Range
V
V
CC
/2
V
CC
2.4
4
_______________________________________________________________________________________
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
81/MAX920
ELECTRICAL CHARACTERISTICS (continued)
(V
= 5V, V
= V
= +14V, V
= (V
- V ) = 0V, V
= V
= 0V, V
= V /2, R = 100kΩ; for MAX9918, A =
REFIN CC L V
CC
RS+
RS-
SENSE
RS+
RS-
SHDN
GND
A
90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, A = 20V/V, R2/R1 = 79kΩ/1kΩ; T = -40°C to +125°C, unless otherwise noted. Typical val-
V
ues are at T = +25°C.) (Note 1)
A
PARAMETERS
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
0V ≤ V
- 1.9V)
≤ (V
≤ (V
REFIN
CC
MAX9918, MAX9919_
82
103
REFIN Common-Mode Rejection
Ratio
REFIN
dB
CMRR
0V ≤ V
REFIN
CC
MAX9920
75
90
- 2.4V)
MAX9918, MAX9919_, V
= V
=
RS-
50mV
100
100
RS+
=
REFIN Current
I
μA
REFIN
MAX9920, V
= V
200mV
RS+
RS-
SHDN Logic-High
V
2.0
V
V
IH
SHDN Logic-Low
V
0.8
5
IL
SHDN Logic Input Current
Supply Voltage Range
0 ≤ V
≤ V
μA
V
SHDN
CC
V
Inferred from PSRR test
MAX9918, MAX9919_ 4.5V ≤ V ≤ 5.5V
4.5
74
68
5.5
CC
103
100
0.7
CC
Power-Supply Rejection Ratio
(Note 3)
PSRR
dB
MAX9920
4.5V ≤ V ≤ 5.5V
CC
T
= +25°C
1.2
1.5
1.6
2.2
10
A
V
= V
= V
= +14V
= -2V
RS+
RS+
RS-
RS-
T = -40°C to +125°C
A
Supply Current
I
mA
μA
CC
T
= +25°C
1.0
A
V
V
T = -40°C to +125°C
A
Shutdown Supply Current
Small Signal -3dB Bandwidth
I
= V = 5V
CC
0.5
75
250
120
230
0.6
0.9
3.0
1.5
12
7
CC_SHDN
SHDN
MAX9918, V
= 50mV
SENSE
MAX9919F, V
= 50mV
= 50mV
SENSE
BW
kHz
MAX9919N, V
SENSE
MAX9920, V
MAX9918
= 200mV
SENSE
MAX9919F
MAX9919N
MAX9920
Slew Rate
SR
V/μs
V
V
V
V
V
V
V
V
= 5mV to 50mV step
SENSE
SENSE
SENSE
SENSE
SENSE
SENSE
SENSE
SENSE
MAX9918
MAX9919F
MAX9919N
MAX9920
= 50mV to 5mV step
= 5mV to 50mV step
= 50mV to 5mV step
= 5mV to 50mV step
= 50mV to 5mV step
= 20mV to 200mV step
= 200mV to 20mV step
3.5
2.5
3.5
3
1% Settling Time from V
Step
SENSE
μs
5
3
_______________________________________________________________________________________
5
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(V
= 5V, V
= V
= +14V, V
= (V
- V ) = 0V, V
= V
= 0V, V
= V /2, R = 100kΩ; for MAX9918, A =
REFIN CC L V
CC
RS+
RS-
SENSE
RS+
RS-
SHDN
GND
A
90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, A = 20V/V, R2/R1 = 79kΩ/1kΩ; T = -40°C to +125°C, unless otherwise noted. Typical val-
V
ues are at T = +25°C.) (Note 1)
A
PARAMETERS
SYMBOL
CONDITIONS
MIN
TYP
2.5
0.5
2.5
0.5
3.5
3.5
0.25
2.5
4.5
5
MAX
UNITS
V
V
V
V
V
V
V
V
= -2V to +14V step
= +14V to -2V step
= -2V to +14V step
= +14V to -2V step
= -2V to +14V step
= +14V to -2V step
= -2V to +14V step
= +14V to -2V step
CM
CM
CM
CM
CM
CM
CM
CM
MAX9918,
= 50mV
V
SENSE
MAX9919F,
= 50mV
V
SENSE
1% Settling Time from V
Step
μs
CM
MAX9919N,
= 50mV
V
SENSE
MAX9920,
= 200mV
V
SENSE
MAX9918, V
= 50mV, 1% settling
SENSE
MAX9919F, V
= 50mV, 1% settling
= 50mV, 1% settling
SENSE
Power-Up Time
μs
MAX9919N, V
6
SENSE
MAX9920, V
= 200mV, 1% settling
5
SENSE
Max Capacitive Load Stability
No sustained oscillations (Note 5)
MAX9918, MAX9919_
MAX9920
50
pF
60
Input Referred Noise Voltage
Density
e
10kHz
nV/√Hz
n
174
Note 1: All devices are 100% production tested at T = +25°C. All temperature limits are guaranteed by design.
A
Note 2: V is extrapolated from two point gain error tests. Measurements are made at V
= 5mV and 50mV for
OS
SENSE
MAX9918/MAX9919N/MAX9919F, and V
= 20mV and 200mV for MAX9920.
SENSE
Note 3: Extrapolated V as described above in Note 2 is used to calculate V drift, CMRR, and PSRR.
OS
OS
81/MAX920
Note 4: OUT should be 100mV away from either rail to achieve rated accuracy, or limited by a V
MAX9918/MAX9919N/MAX9919F and 200mV for the MAX9920.
of 50mV for the
SENSE
Note 5: Not production tested. Guaranteed by design.
6
_______________________________________________________________________________________
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
81/MAX920
Typical Operating Characteristics
(V
CC
= 5V, T = +25°C, unless otherwise noted.)
A
V
DRIFT
= +14V)
V
RS+
OS
OS
OS
= -2V)
(V
= +14V)
(V
RS+
0.30
0.25
0.20
0.15
0.10
0.05
0
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
-4 -3 -2 -1
0
1
2
3
4
-400 -320-240-160 -80
0
80 160 240 320 400
-400 -320-240-160 -80
0
80 160 240 320 400
OFFSET VOLTAGE (FV/°C)
OFFSET VOLTAGE (FV)
OFFSET VOLTAGE (FV)
V
DRIFT
= -2V)
OS
V
vs. V
CC
(V
V
OS
vs. V
OS
RS+
CM
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
500
400
300
200
100
0
125
100
75
T
= -40°C
A
T
A
= +25°C
V
= 14V
CM
50
25
0
-100
-200
-300
-400
-500
-25
-50
-75
-100
T
A
= +125°C
MAX9918ASA
V
= -2V
CM
V
V
= 5V
= V
MAX9918ASA
CC
V
V
= 5V
REF
GND
CC
= V
GND
REF
-10 -8 -6 -4 -2
0
2
4
6
8
10
-20 -10
0
10 20 30 40 50 60 70 80
(V)
4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5
(V)
OFFSET VOLTAGE (FV/°C)
V
CM
V
CC
GAIN ERROR
= +14V, MAX9919F, A = +45V/V)
GAIN ERROR
= +14V, MAX9919N, A = +90V/V)
GAIN ERROR
= -2V, MAX9919F, A = +45V/V)
(V
RS+
(V
RS+
(V
RS+
V
V
V
0.6
0.5
0.4
0.3
0.2
0.1
0
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0.6
0.5
0.4
0.3
0.2
0.1
0
-0.4 -0.3 -0.2 -0.1
0
0.1 0.2 0.3 0.4
-0.4 -0.3 -0.2 -0.1 0
0.1 0.2 0.3 0.4
-0.4 -0.3 -0.2 -0.1
0
0.1 0.2 0.3 0.4
GAIN ERROR (%)
GAIN ERROR (%)
GAIN ERROR (%)
_______________________________________________________________________________________
7
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
Typical Operating Characteristics (continued)
(V
CC
= 5V, T = +25°C, unless otherwise noted.)
A
GAIN ERROR
= -2V, MAX9919N, A = +90V/V)
GAIN ERROR vs. V
CM
(V
RS+
V
2.0
1.6
0.6
0.5
0.4
0.3
0.2
0.1
0
1.2
T = +125NC
A
0.8
T = +25NC
A
0.4
0
-0.4
-0.8
-1.2
-1.6
-2.0
T = -40NC
A
MAX9918ASA
V
V
= 5V
CC
= V
GND
REF
-20 -10
0
10 20 30 40 50 60 70 80
(V)
-0.4 -0.3 -0.2 -0.1
0
0.1 0.2 0.3 0.4
V
GAIN ERROR (%)
CM
GAIN ERROR vs. V
LINEARITY vs. V
CC
SENSE
0.5
0.4
0.25
0.20
0.15
0.10
0.05
0
V
V
V
A
= -2V
= 5V
REFIN
CM
CC
= V /2
CC
0.3
= 90V/V
V
T
= -40°C
= +25°C
0.2
A
BIDIRECTIONAL
0.1
V
= -2V
CM
0
81/MAX920
-0.05
-0.10
-0.15
-0.20
-0.25
-0.1
-0.2
-0.3
-0.4
-0.5
T
= +125°C
A
T
A
V
CM
= 14V
5.1
-30
-20
-10
0
10
20
30
4.5
4.7
4.9
5.3
5.5
V
(mV)
SENSE
V
CC
(V)
LINEARITY vs. V
LINEARITY vs. V
SENSE
SENSE
0.10
0.08
0.06
0.04
0.02
0
0.10
0.08
0.06
0.04
0.02
0
V
V
V
A
= +14V
= 5V
V
V
= -2V
CM
CC
CM
CC
= 5V
= V
= V /2
CC
V
A
REFIN
REFIN
GND
= 90V/V
= 90V/V
V
V
T = -40°C
A
T
A
= +25°C
BIDIRECTIONAL
UNIDIRECTIONAL
T
A
= +25°C T = -40°C
A
-0.02
-0.04
-0.06
-0.08
-0.10
-0.02
-0.04
-0.06
-0.08
-0.10
T
A
= +125°C
T
A
= +125°C
0
10 20 30 40 50 60 70 80
(mV)
-30
-20
-10
0
10
20
30
V
V
(mV)
SENSE
SENSE
8
_______________________________________________________________________________________
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
81/MAX920
Typical Operating Characteristics (continued)
(V
CC
= 5V, T = +25°C, unless otherwise noted.)
A
LINEARITY vs. V
LINEARITY vs. V
SENSE
SENSE
0.20
0.18
0.16
0.14
0.12
0.10
0.08
0.06
0.04
0.02
0
0.25
0.20
0.15
V
V
V
= +14V
= 5V
V
V
V
= -2V
CM
CC
CM
CC
= 5V
= V /2
= V
GND
REFIN
REFIN
CC
A = 90V/V
A = 30V/V
V
V
T
= +25°C
0.10
0.05
A
T
UNIDIRECTIONAL
BIDIRECTIONAL
T
= -40°C
A
T
= +25°C
A
0
-0.05
-0.10
-0.15
-0.20
T
= -40°C
A
= +125°C
A
-0.02
-0.04
-0.06
-0.08
-0.10
T
A
= +125°C
-0.25
0
5 10 15 20 25 30 35 40 45 50 55 60 65 70
(mV)
-100 -80 -60
-20
0
20 40 60 80 100
(mV)
-40
V
V
SENSE
SENSE
V
V
vs. V
LINEARITY vs. V
OUT - REFIN
SENSE
SENSE
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0.10
0.08
0.06
V
V
V
= +14V
= 5V
-2V V : SOLID LINE
CM
CM
CC
14V V : DASHED LINE
CM
= V /2
REFIN
CC
T
= -40°C
A
A = 30V/V
T
= +125°C
= +25°C
V
A
0.04
0.02
BIDIRECTIONAL
0
-0.02
-0.04
-0.06
-0.08
T
A
MAX9918, V
UNIDIRECTIONAL,
GAIN = 90V/V
= 0V
REFIN
-0.5
-1.0
-0.10
-100 -80 -60 -40 -20
V
0
20 40 60 80 100
-20 -10
0
10 20 30 40 50 60 70 80
V
(mV)
(mV)
SENSE
SENSE
V
- V
REFIN
vs. V
V /V vs. I
OH OL OH
OUT
SENSE
3.0
2.5
350
300
250
200
150
100
50
V
= +14V
-2V V : SOLID LINE
CM
CM
14V V : DASHED LINE
CM
2.0
1.5
1.0
V
- V
CC OH
0.5
0
-0.5
-1.0
-1.5
-2.0
-2.5
-3.0
MAX9918, V
BIDIRECTIONAL,
GAIN = 90V/V
= V /2
CC
REFIN
V
OL
7
0
-40 -30 -20 -10
0
10 20 30 40
(mV)
0
1
2
3
4
5
6
8
9
10
V
I
(mA)
SENSE
OH
_______________________________________________________________________________________
9
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
Typical Operating Characteristics (continued)
(V
CC
= 5V, T = +25°C, unless otherwise noted.)
A
I
vs. V
I
vs.V
I
vs. V
BIAS CM
CC
CC
CC
CM
1.0
1.6
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
100
80
V
= 0V (DASH)
+ 50mV (SOLID)
SENSE
T = +125NC
A
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
V
SENSE
60
V
V
= -2V
= 14V
40
CM
20
T = -40NC
T = +25NC
A
A
0
CM
-20
-40
-60
-80
-100
MAX9918
V = 5V
CC
V
= 0V
SENSE
4.5 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5
(V)
-20 -10
0
10 20 30 40 50 60 70 80
(V)
-20 -10
0
10 20 30 40 50 60 70 80
(V)
V
V
V
CM
CC
CM
INPUT LEAKAGE CURRENT vs. V
DIFFERENTIAL R vs. V
IN CM
CM
GAIN vs. FREQUENCY
20
15
10
5
0
1000
900
800
700
600
500
400
300
200
100
0
50
40
T = +25NC
A
30
T = -40NC
A
20
-5
-10
-15
-20
-25
-30
-35
-40
-45
-50
10
81/MAX920
0
T = +125NC
A
-10
-20
-30
-40
IN+ - IN- = 50mV
MAX9918
= 14V
V
V
= V
= 0V
CC
SHDN
V
CM
= 0V
REFIN
GAIN = 90V/V
-20
0
20
40
(V)
60
80
-20
-5
10
25
(V)
40
55
70
0.001 0.01
0.1
1
10
V
V
CM
CM
FREQUENCY (MHz)
GAIN vs. FREQUENCY
PSRR vs. FREQUENCY
GAIN vs. FREQUENCY
10
0
0
-20
40
30
MAX9918
= 14V
GAIN = 90V/V
MAX9918
V
V
V
= 14V
= 50mV
CM
CM
SENSE
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
20
-40
10
0
-60
-10
-20
-30
-40
-50
-60
-80
V
= -2V
CM
-100
-120
-140
MAX9920
= 14V
GAIN = 20V/V
V
CM
V
CM
= 14V
0.001 0.01
0.1
1
10
0.001
0.01
0.1
1
10
100
0.0001 0.001 0.01 0.1
1
10 100 1k 10k
FREQUENCY (MHz)
FREQUENCY (MHz)
FREQUENCY (kHz)
10 ______________________________________________________________________________________
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
81/MAX920
Typical Operating Characteristics (continued)
(V
CC
= 5V, T = +25°C, unless otherwise noted.)
A
SMALL-SIGNAL TRANSIENT
(GAIN = 45V/V)
SMALL-SIGNAL TRANSIENT
(GAIN = 90V/V)
MAX9918 toc31
MAX9918 toc32
5mV/div
5mV/div
MAX9918, V = 14V
MAX9918, V = 14V
CM
CM
100mV/div
50mV/div
V
= 10mV TO 15mV
V
= 10mV TO 15mV
SENSE
SENSE
10Fs/div
10Fs/div
LARGE-SIGNAL TRANSIENT
(GAIN = 45V/V)
LARGE-SIGNAL TRANSIENT
(GAIN = 90V/V)
MAX9918 toc33
MAX9918 toc34
50mV/div
50mV/div
MAX9918, V = 14V
MAX9918, V = 14V
CM
CM
1V/div
500mV/div
V
= 0V TO 50mV
V
= 0 TO 50mV
SENSE
SENSE
10Fs/div
10Fs/div
OUTPUT RESPONSE TO
COMMON-MODE TRANSIENT
COMMON-MODE STEP RESPONSE
MAX9918 toc35
MAX9918 toc36
MAX9918, V = 14V
CM
S
= PS (50mV)
SENSE
V
CM
50V/div
10V/div
1V/div
0
V
OUT
100mV/div
OUTPUT AC-COUPLED
FULL SCALE
AT THE INPUT
4µs/div
10Fs/div
______________________________________________________________________________________ 11
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
Typical Operating Characteristics (continued)
(V
CC
= 5V, T = +25°C, unless otherwise noted.)
A
SHUTDOWN ON/OFF DELAY
POWER-UP TIME
MAX9918 toc37
MAX9918 toc38
5V/div
5V/div
2V/div
1V/div
MAX9918, V = 14V
MAX9918, V = 14V
CM
CM
V
= PS (50mV)
V
= PS (50mV)
SENSE
SENSE
4Fs/div
4Fs/div
OUTPUT OVERDRIVE
RECOVERY (30V/V)
OUTPUT OVERDRIVE
RECOVERY (90V/V)
MAX9918 toc39
MAX9918 toc40
MAX9918, V = 14V
CM
V
= 2 x PS
SENSE
50mV/div
200mV/div
81/MAX920
2V/div
2V/div
MAX9918, V = 14V
CM
V
= 2 x PS
SENSE
4Fs/div
4Fs/div
12 ______________________________________________________________________________________
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
81/MAX920
Pin Configuration
TOP VIEW
+
RS+
RS-
1
2
3
4
8
7
6
5
V
CC
MAX9918
MAX9919
MAX9920
REFIN
FB
SHDN
GND
EP*
OUT
8 SOIC-EP
*EXPOSED PAD. CONNECT EP TO SOLID GROUND FOR
PROPER THERMAL AND ELECTRICAL PERFORMANCE.
Pin Description
PIN
1
NAME
RS+
FUNCTION
Positive Current-Sensing Input. Power side connects to external sense resistor.
Negative Current-Sensing Input. Load side connects to external sense resistor.
Active-High Shutdown Input. Connect to GND for normal operation.
Ground
2
RS-
3
SHDN
GND
OUT
4
5
Current-Sense Output. V
is proportional to V
.
OUT
SENSE
Feedback Input. Connect FB to a resistive-divider network to set the gain for the MAX9918 and
MAX9920. See the Adjustable Gain (MAX9918/MAX9920) section for more information. Leave FB
unconnected for the MAX9919 for proper operation.
6
FB
Reference Input. Set REFIN to V /2 for bidirectional operation. Set REFIN to GND for unidirectional
CC
operation.
7
8
REFIN
V
5V Supply Voltage Input. Bypass V
to GND with 0.1μF capacitor.
CC
CC
Exposed Pad. Connect to a large-area contiguous ground plane for improved power dissipation. Do
not use as the only ground connection for the part.
—
EP
The level shifters translate V
to an internal refer-
SENSE
Detailed Description
ence voltage where it is then amplified with an instru-
mentation amplifier. The instrumentation amplifier
configuration provides high precision with input offset
voltages of 400μV (max). Indirect feedback of the
instrumentation amplifier allows the gain to be adjusted
with an external resistive-divider network on the
MAX9918/MAX9920. The MAX9919 is a fixed gain
device available with laser-trimmed resistors for gains
of 45V/V (MAX9919F) and 90V/V (MAX9919N).
The MAX9918/MAX9919/MAX9920 are single-supply,
high-accuracy uni-/bidirectional current-sense amplifiers
with a high common-mode input range that extends from
-20V to +75V. The MAX9918/MAX9919/MAX9920’s input
stage utilizes a pair of level shifters allowing a wide
common-mode operating range when measuring the
voltage drop (V
) across the current-sense resistor.
SENSE
The first level shifter accommodates the upper common-
mode operating range from +2V to +75V. When the
common-mode voltage falls below +2V, the second level
shifter is used to accommodate negative voltages down
to -20V.
The MAX9918/MAX9919 operate with a full-scale sense
voltage of 50mV. The input stage of the MAX9920 pro-
vides an attenuation factor of 4, enabling a full-scale
sense voltage of 200mV.
______________________________________________________________________________________ 13
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
The MAX9918/MAX9919 operate in bidirectional mode
by application of a low-source impedance reference
Uni-/Bidirectional Operation
The MAX9918/MAX9919/MAX9920 support both unidi-
rectional and bidirectional operation. The devices oper-
voltage in the 0V to V
- 1.9V range, (typically V /2),
CC
CC
to REFIN. For the MAX9920, the reference voltage range
ate in unidirectional mode with V
= V
. The
GND
REFIN
is 0V to V
- 2.4V (typically V /2). The output voltage
CC
output is then referenced to ground and the output volt-
CC
V
relative to V
is then proportional to the
REFIN
age V
(V
is proportional to the positive voltage drop
OUT
V
OUT
voltage drop from RS+ to RS- (Figure 2).
) from RS+ to RS- (Figure 1).
SENSE
SENSE
V
OUT
3.6V
2.7V
1.8V
G = 90V/V
I
DISCHARGE
R
SENSE
RS+
RS-
LOAD
MAX9919N
DISCHARGE
CURRENT
V
TO ADC
OUT
5V
CC
SHDN
REFIN
0.9V
GND
V
SENSE
0
10mV
30mV
20mV
20mV
81/MAX920
Figure 1. Unidirectional Operation
V
- V
REFIN
OUT
G = 90V/V
1.8V
I
I
CHARGE
DISCHARGE
R
SENSE
DISCHARGE
CURRENT
0.9V
RS+
RS-
LOAD
MAX9919N
V
SENSE
-20mV
10mV
-10mV
0
20mV
V
TO ADC
OUT
5V
CC
CHARGE
CURRENT
2.5V
SHDN
REFIN
-0.9V
-1.8V
GND
Figure 2. Bidirectional Operation
14 ______________________________________________________________________________________
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
81/MAX920
Sense Resistor, R
Shutdown Mode
Drive SHDN high to enter low-power shutdown mode.
In shutdown mode, the MAX9918/MAX9919/MAX9920
draw 0.5μA (typ) of quiescent current.
SENSE
Choose R
based on the following criteria:
SENSE
Accuracy: A high R
value allows lower currents
SENSE
to be measured more accurately. This is because off-
sets become less significant when the sense voltage is
Adjustable Gain (MAX9918/MAX9920)
The MAX9918/MAX9920 feature externally adjustable
gain set by a resistive-divider network circuit using
resistors R1 and R2 (see the Functional Diagram). The
gain frequency compensation is set for a minimum gain
of 30V/V for the MAX9918 and 7.5V/V for the MAX9920.
The gain G for the MAX9918/MAX9920 is given by the
following equation:
larger. In the linear region (100mV < V
< V
CC
OUT
- 100mV), there are two components to accuracy: input
offset voltage (V ) and gain error (GE). Use the linear
OS
equation to calculate total error:
V
OUT
= (G GE) x (V
V
OS
)
SENSE
For best performance, select R
to provide
SENSE
approximately 50mV (MAX9918/MAX9919) or 200mV
(MAX9920) of sense voltage for the full-scale current in
each application. Sense resistors of 5mΩ to 100mΩ are
available with 1% accuracy or better.
R2
R1
⎛
⎞
G = 1+
(for MAX9918)
⎜
⎟
⎠
⎝
and
Efficiency and Power Dissipation
R2
R1
4
At high current levels, the I2R losses in R
can be
SENSE
⎛
⎜
⎜
⎜
⎞
⎟
⎛
⎞
1+
⎜
⎝
⎟
⎠
significant. Take this into consideration when choosing
the resistor value and its power dissipation (wattage)
rating. Also, the sense resistor’s value might drift if it is
G =
(for MAX9920)
⎟
⎟
⎜
⎝
⎟
⎠
allowed to heat up excessively. The precision V
of
OS
the MAX9918/MAX9919/MAX9920 allows the use of
small sense resistors to reduce power dissipation and
reduce hot spots.
Applications Information
Component Selection
Inductance: Keep inductance low if I
has a large
SENSE
Ideally, the maximum load current develops the full-
scale sense voltage across the current-sense resistor.
Choose the gain needed to yield the maximum output
voltage required for the application:
high-frequency component by using resistors with low
inductance value.
Power-Supply Bypassing and Grounding
Bypass the MAX9918/MAX9919/MAX9920’s V
to
CC
V
OUT
= V
x G
SENSE
ground with a 0.1μF capacitor. Grounding these
devices requires no special precautions; follow the
same cautionary steps that apply to the rest of the sys-
tem. High-current systems can experience large volt-
age drops across a ground plane, and this drop may
where V
is the full-scale sense voltage, 50mV for
SENSE
the MAX9918/MAX9919, or 200mV for the MAX9920
and G is the gain of the device. G is externally
adjustable for the MAX9918/MAX9920. The MAX9919
has a fixed gain version of 45V/V (MAX9919F) or 90V/V
(MAX9919N).
add to or subtract from V
. Using a differential mea-
OUT
surement between OUT and REFIN prevents this prob-
lem. For highest current-measurement accuracy, use a
single-point star ground. Connect the exposed pad to a
solid ground to ensure optimal thermal performance.
In unidirectional applications (V
= 0V), select the
REFIN
gain of the MAX9918/MAX9920 to utilize the full output
range between GND and V . In bidirectional applica-
CC
tions (V
= V /2), select the gain to allow an output
REFIN
voltage range of
CC
V
/2. V
CC
must be at least 100mV
OUT
from either rail to achieve the rated gain accuracy.
______________________________________________________________________________________ 15
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
Functional Diagram
V
CC
MAX9919F
OUT
FB
A
R2
R1
RS+
INPUT
INPUT STAGE/
LEVEL SHIFTER
50mV (typ)
R
SENSE
RS-
REFIN
I
LOAD
FIXED GAIN
G = 45V/V OR 90V/V
SHDN
GND
V
CC
MAX9918
MAX9920
OUT
FB
A
R2
R1
RS+
MAX9918
50mV (typ)
INPUT
INPUT STAGE/
LEVEL SHIFTER
R
SENSE
RS-
MAX9920
REFIN
200mV (typ)
81/MAX920
I
LOAD
ADJUSTABLE GAIN
SHDN
GND
GAIN IS SET BY EXTERNAL RESISTORS, R1 AND R2
G = [1+(R2/R1)] FOR MAX9918
G = [1+(R2/R1)]/4 FOR MAX9920
Chip Information
PROCESS: BiCMOS
16 ______________________________________________________________________________________
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
81/MAX920
Package Information
For the latest package outline information and land patterns (footprints), go to www.maxim-ic.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 per-
tains to the package regardless of RoHS status.
PACKAGE TYPE
PACKAGE CODE
OUTLINE NO.
21-0111
LAND PATTERN NO.
90-0151
8 SOIC-EP
S8E+14
______________________________________________________________________________________ 17
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
Revision History
REVISION REVISION
PAGES
CHANGED
DESCRIPTION
NUMBER
DATE
0
1
2
3
4
10/09
1/10
Initial release
—
16
1
Updated Functional Diagram
Added automotive qualified part
12/10
6/11
Added MAX9920ASA/V+ to data sheet
1
7/11
Added automotive qualified parts for the MAX9919NASA/V+ and the MAX9920ASA/V+
1
81/MAX920
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
18 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2011 Maxim Integrated Products
Maxim is a registered trademark of Maxim Integrated Products, Inc.
相关型号：
MAX9919FASA+T
Operational Amplifier, 1 Func, 1300uV Offset-Max, BICMOS, PDSO8, ROHS COMPLIANT, MS-012, SOIC-8
MAXIM
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