LM3824 Datasheet, PDF (1/12 Pages) National Semiconductor (TI) – Precision Current Gauge IC with Internal Zero Ohm Sense Element and PWM Output

July 2000
LM3824
Precision Current Gauge IC with Internal Zero Ohm
Sense Element and PWM Output
General Description
The LM3824 Current Gauge provides easy to use precision
current measurement with virtually zero insertion loss (typi-
cally 0.003Ω). The LM3824 is used for high-side sensing.
A Delta Sigma analog to digital converter is incorporated to
precisely measure the current and to provide a current aver-
aging function. Current is averaged over 6 msec time peri-
ods in order to provide immunity to current spikes. The ICs
have a pulse-width modulated (PWM) output which indicates
the current magnitude and direction. The shutdown pin can
be used to inhibit false triggering during start-up, or to enter
a low quiescent current mode.
The LM3824 is factory-set in two different current options.
The sense range is −1.0A to +1.0A or −2.0A to +2.0A. The
sampling interval for this part is 6ms. If a more precise mea-
surement is required, please refer to LM3822 datasheet.
Key Specifications
n Ultra low insertion loss (0.003Ω)
n 2V to 5.5V supply range
n ±3% accuracy at room temperature for the 1A device
(includes accuracy of the internal sense element)
n Low quiescent current in shutdown mode
(typically 1.8 µA)
n 6 msec sampling interval
n In MSOP-8 Package
Features
n No external sense element required
n PWM output indicates the current magnitude and
direction
n PWM output is easily interfaced with microprocessors
and controllers
n Precision ∆Σ current-sense technique
n Low temperature sensitivity
n Internal filtering rejects false trips
n Internal Power-On-Reset (POR)
n DC Offset is less than 8 mA for 1A part
Applications
n Battery charge/discharge gauge
n Motion control diagnostics
n Power supply load monitoring and management
n Resettable smart fuse
Connection Diagram
DS200007-1
Top View
LM3824 for High-Side Sensing
© 2000 National Semiconductor Corporation DS200007
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