LT1999-10/LT1999-20/
LT1999-50
High Voltage, Bidirectional
Current Sense Amplifier
FeaTures
DescripTion
The LT®1999 is a high speed precision current sense
amplifier, designed to monitor bidirectional currents over
a wide common mode range. The LT1999 is offered in
three gain options: 10V/V, 20V/V, and 50V/V.
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Buffered Output with 3 Gain Options:
10V/V, 20V/V, 50V/V
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Gain Accuracy: 0.5% Max
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Input Common Mode Voltage Range: –5V to 80V
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AC CMRR > 80dB at 100kHz
The LT1999 senses current via an external resistive shunt
andgeneratesanoutputvoltage,indicatingbothmagnitude
and direction of the sensed current. The output voltage is
referencedhalfwaybetweenthesupplyvoltageandground,
or an external voltage can be used to set the reference
level. With a 2MHz bandwidth and a common mode input
range of –5V to 80V, the LT1999 is suitable for monitoring
currents in H-Bridge motor controls, switching power
supplies, solenoid currents, and battery charge currents
from full charge to depletion.
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Input Offset Voltage: 1.5mV Max
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–3dB Bandwidth: 2MHz
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Smooth, Continuous Operation Over Entire Common
Mode Range
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4kV HBM Tolerant and 1kV CDM Tolerant
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Low Power Shutdown <10µA
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–55°C to 150°C Operating Temperature Range
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8-Lead MSOP and 8-Lead SO (Narrow) Packages
applicaTions
The LT1999 operates from an independent 5V supply and
draws1.55mA.Ashutdownmodeisprovidedforminimiz-
ing power consumption.
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High Side or Low Side Current Sensing
H-Bridge Motor Control
Solenoid Current Sense
The LT1999 is available in an 8-lead MSOP or SOP package.
High Voltage Data Acquisition
PWM Control Loops
Fuse/MOSFET Monitoring
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Typical applicaTion
Full Bridge Armature Current Monitor
+
V
LT1999
V
S
5V
+
2µA
V
V
OUT
1
2
8
7
SHDN
V
SHDN
2.5V
R
+
–
G
4k
V
V
+IN
–IN
–
+
R
+
S
V
V
OUT
REF
V
0.8k
0.8k
+
V
+IN
V
160k
160k
4k
+
3
4
6
5
5V
V
0.1µF
1999 TA01b
TIME (10µs/DIV)
0.1µF
1999 TA01a
1999fb
1