MAX9920

Manufacturer Part NumberMAX9920
DescriptionThe MAX9918/MAX9919/MAX9920 are single-supply, high-accuracy current-sense amplifiers with a high input common-mode range that extends from -20V to +75V
ManufacturerMaxim
MAX9920 datasheet
 


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19-5015; Rev 4; 7/11
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
General Description
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.
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-
ate as unidirectional amplifiers when V
and as bidirectional amplifiers when V
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).
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.
H-Bridge Motor Current Sensing
Solenoid Current Sensing
Current Monitoring of Inductive Loads
High- and Low-Side Precision Current Sensing
4x4 Transmission Control
Electronic Throttle Control
Super-Capacitor Charge/Discharge Monitoring in
Hybrid Cars
Precision High-Voltage Current Monitoring
V
BATT
φ1A
R
SENSE
M
φ2B
________________________________________________________________ Maxim Integrated Products
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.
o -20V to +75V Input Common-Mode Voltage Range
o 400µV (max) Input Offset Voltage
o 0.6% (max) Gain Accuracy Error
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
o 0.5µA (typ) Shutdown Current
o Rail-to-Rail Output
= GND
REFIN
o -40°C to +125°C Automotive Temperature Range
= V
/2.
REFIN
CC
PART
MAX9918ASA+
MAX9918ASA/V+
Applications
MAX9919FASA+
MAX9919NASA+
MAX9919NASA/V+
MAX9920ASA+
MAX9920ASA/V+
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.
V
CC
φ2B
MAX9918
MAX9920
RS+
INPUT STAGE
LEVEL SHIFTER
RS-
ADJUSTABLE GAIN
φ1B
SHDN
GND
Features
Ordering Information/
Selector Guide
V
GAIN
PIN-
SENSE
(mV)
(V/V)
PACKAGE
±50
Adjustable
8 SOIC-EP*
±50
Adjustable
8 SOIC-EP*
±50
45
8 SOIC-EP*
±50
90
8 SOIC-EP*
±50
90
8 SOIC-EP*
±200
Adjustable
8 SOIC-EP*
±200
Adjustable
8 SOIC-EP*
Typical Operating Circuit
V
CC
OUT
A
ADC
R2
FB
R1
REFIN
REF
μC
GND
1

MAX9920 Summary of contents

  • Page 1

    ... The MAX9918/MAX9919/MAX9920 oper- ate as unidirectional amplifiers when V and as bidirectional amplifiers when V The MAX9920 attenuates the input signal by a factor the input level-shifting stage allowing the device to sense voltages up to 200mV (unidirectional operation) or ±100mV (bidirectional operation). ...

  • Page 2

    ... ELECTRICAL CHARACTERISTICS ( +14V RS+ RS- SENSE 90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, A ues are +25°C.) (Note 1) A PARAMETER SYMBOL Input Offset Voltage (Note 2) 2 _______________________________________________________________________________________ Output Short Circuit to V Continuous Current into Any Pin (Not to exceed package power dissipation) ................± ...

  • Page 3

    ... Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers ELECTRICAL CHARACTERISTICS (continued 5V +14V RS+ RS- SENSE 90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, A ues are +25°C.) (Note 1) A PARAMETERS SYMBOL Input Offset Voltage Drift (Note 3) Common-Mode Range Common-Mode Rejection Ratio CMRR ...

  • Page 4

    ... Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers ELECTRICAL CHARACTERISTICS (continued 5V +14V RS+ RS- SENSE 90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, A ues are +25°C.) (Note 1) A PARAMETER SYMBOL Gain Error (Note 2) FB Input Bias Current Output-Voltage High (Note 4) V ...

  • Page 5

    ... Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers ELECTRICAL CHARACTERISTICS (continued 5V +14V RS+ RS- SENSE 90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, A ues are +25°C.) (Note 1) A PARAMETERS SYMBOL REFIN Common-Mode Rejection RE FIN Ratio REFIN Current SHDN Logic-High ...

  • Page 6

    ... Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers ELECTRICAL CHARACTERISTICS (continued 5V +14V RS+ RS- SENSE 90V/V, R2/R1 = 89kΩ/1kΩ; for MAX9920, A ues are +25°C.) (Note 1) A PARAMETERS SYMBOL 1% Settling Time from V Step CM Power-Up Time Max Capacitive Load Stability ...

  • Page 7

    Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers ( +25°C, unless otherwise noted +14V) RS+ 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0 -400 -320 -240-160 ...

  • Page 8

    Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers ( +25°C, unless otherwise noted GAIN ERROR (V = -2V, MAX9919N, A RS+ 0.6 0.5 0.4 0.3 0.2 0.1 0 -0.4 -0.3 -0.2 -0.1 GAIN ...

  • Page 9

    Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers ( +25°C, unless otherwise noted LINEARITY vs +14V 0.14 REFIN GND ...

  • Page 10

    ... IN+ - IN- = 50mV - SHDN - REFIN -50 - (V) CM GAIN vs. FREQUENCY -10 -20 -30 -40 MAX9920 V = 14V -50 CM GAIN = 20V/V -60 0.001 0.01 0 FREQUENCY (MHz) 10 ______________________________________________________________________________________ Typical Operating Characteristics (continued (DASH) SENSE T = +125NC 1 50mV (SOLID) SENSE 1 ...

  • Page 11

    Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers ( +25°C, unless otherwise noted SMALL-SIGNAL TRANSIENT (GAIN = 45V/V) 5mV/div MAX9918, V 50mV/div V = 10mV TO 15mV SENSE 10Fs/div LARGE-SIGNAL TRANSIENT (GAIN = ...

  • Page 12

    Input Range, Precision Uni-/Bidirectional, Current-Sense Amplifiers ( +25°C, unless otherwise noted SHUTDOWN ON/OFF DELAY 5V/div 1V/div OUTPUT OVERDRIVE RECOVERY (30V/V) 200mV/div 2V/div 12 ______________________________________________________________________________________ Typical Operating Characteristics (continued) MAX9918 toc37 5V/div ...

  • Page 13

    ... OUT Current-Sense Output. V Feedback Input. Connect resistive-divider network to set the gain for the MAX9918 and 6 FB MAX9920. See the Adjustable Gain (MAX9918/MAX9920) section for more information. Leave FB unconnected for the MAX9919 for proper operation. Reference Input. Set REFIN REFIN operation ...

  • Page 14

    ... MAX9919N SHDN GND Figure 2. Bidirectional Operation 14 ______________________________________________________________________________________ The MAX9918/MAX9919 operate in bidirectional mode by application of a low-source impedance reference voltage in the REFIN. For the MAX9920, the reference voltage range = V . The REFIN GND relative to V OUT ±V SENSE V OUT 3 ...

  • Page 15

    ... 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: ⎛ ⎞ R ...

  • Page 16

    ... INPUT STAGE/ LEVEL SHIFTER SHDN GND V CC MAX9918 MAX9920 INPUT INPUT STAGE/ LEVEL SHIFTER SHDN GND GAIN IS SET BY EXTERNAL RESISTORS, R1 AND [1+(R2/R1)] FOR MAX9918 G = [1+(R2/R1)]/4 FOR MAX9920 PROCESS: BiCMOS Functional Diagram OUT REFIN FIXED GAIN G = 45V/V OR 90V/V OUT ...

  • Page 17

    ... Uni-/Bidirectional, Current-Sense Amplifiers For the latest package outline information and land patterns (footprints 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 ...

  • Page 18

    ... Added automotive qualified parts for the MAX9919NASA/V+ and the MAX9920ASA/V+ 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. ...