Datasheet

MAX9918/MAX9919/MAX9920
-20V to +75V Input Range, Precision
Uni-/Bidirectional, Current-Sense Amplifiers
EVALUATION KIT AVAILABLE
19-5015; Rev 5; 1/13
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
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
REFIN
= GND
and as bidirectional amplifiers when V
REFIN
= V
CC
/2.
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.
Applications
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
Features
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
o -40°C to +125°C Automotive Temperature Range
M
φ2B
φ1B
ADC
REF
A
INPUT STAGE
LEVEL SHIFTER
R
SENSE
V
BATT
ADJUSTABLE GAIN
V
CC
V
CC
RS+
RS-
FB
OUT
REFIN
R2
R1
GND
GND
SHDN
φ2B
φ1A
MAX9918
MAX9920
μC
Typical Operating Circuit
Ordering Information/
Selector Guide
PART
V
SENSE
(mV)
GAIN
(V/V)
PIN-
PACKAGE
MAX9918ASA+ ±50 Adjustable 8 SO-EP*
MAX9918ASA/V+ ±50 Adjustable 8 SO-EP*
MAX9919FASA+ ±50 45 8 SO-EP*
MAX9919FASA/V+ ±50 45 8 SO-EP*
MAX9919NASA+ ±50 90 8 SO-EP*
MAX9919NASA/V+ ±50 90 8 SO-EP*
MAX9920ASA+ ±200 Adjustable 8 SO-EP*
MAX9920ASA/V+ ±200 Adjustable 8 SO-EP*
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.