LT1999-10/LT1999-20/
LT1999-50
High Voltage, Bidirectional
Current Sense Amplifier
Features
nn Buffered Output with 3 Gain Options:
10V/V, 20V/V, 50V/V
nn Gain Accuracy: 0.5% Max
nn Input Common Mode Voltage Range: –5V to 80V
nn AC CMRR > 80dB at 100kHz
nn Input Offset Voltage: 1.5mV Max
nn –3dB Bandwidth: 2MHz
nn Smooth, Continuous Operation Over Entire Common
Mode Range
nn 4kV HBM Tolerant and 1kV CDM Tolerant
nn Low Power Shutdown <10µA
nn –55°C to 150°C Operating Temperature Range
nn 8-Lead MSOP and 8-Lead SO (Narrow) Packages
nn 8-Lead MSOP Pinout Option Engineered for FMEA
Applications
nn High Side or Low Side Current Sensing
nn H-Bridge Motor Control
nn Solenoid Current Sense
nn High Voltage Data Acquisition
nn PWM Control Loops
nn Fuse/MOSFET Monitoring
Description
The LT®1999 is a high speed precision current sense am-
plifier, 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.
The LT1999 senses current via an external resistive shunt
and generates an output voltage, indicating both magnitude
and direction of the sensed current. The output voltage is
referenced halfway between the supply voltage and ground,
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 monitor-
ing currents in H-Bridge motor controls, switching power
supplies, solenoid currents, and battery charge currents
from full charge to depletion.
The LT1999 operates from an independent 5V supply
and draws 1.55mA. A shutdown mode is provided for
minimizing power consumption.
The LT1999 is available in an 8-lead SOP, an 8-lead MSOP
(original pinout), or an 8-lead pinout option engineered
for FMEA.
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
VS
RS
5V
1
V+
V+IN 2
4k
V–IN
V+
3 4k
5V
4
0.1µF
V+
LT1999
SHDN
+
–
0.8k
0.8k
V+
2µA
RG
8 VSHDN
–
+
V+
7 VOUT
160k
6 VREF
160k
5
0.1µF
1999 TA01a
For more information www.linear.com/LT1999
Full Bridge Armature Current Monitor
VOUT
2.5V
V+IN
TIME (10µs/DIV)
1999 TA01b
1999fd
1
