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Features
No external sense element required
PWM output indicates the current magnitude and direction
PWM output is easily interfaced with microprocessors and controllers
Precision ΔΣ current-sense technique
Low temperature sensitivity
Internal filtering rejects false trips
Internal Power-On-Reset (POR)
DC Offset is less than 1 mA for 1A part
Description The LM3822 Current Gauge provides easy to use precision current measurement with virtually zero insertion loss (typically
0.003Ω). The LM3822 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 averaging
function. Current is averaged over 50 msec time periods 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 LM3822 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 50ms. If faster sampling is desired, please refer to the data sheet for the part number LM3824.
Key Specification
Ultra low insertion loss (typically 0.003Ω)
2V to 5.5V supply range
±2% accuracy at room temperature for the 1A device (includes accuracy of the internal sense element)
Low quiescent current in shutdown mode (typically
1.8 µA)
50 msec sampling interval
In MSOP-8 Package
Applications
Battery charge/discharge gauge
Motion control diagnostics
Power supply load monitoring and management
Resettable smart fuse
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