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Details, datasheet, quote on part number:LM3822MMX-1.0
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| Part: | LM3822MMX-1.0 |
| Category: | Power Management => Supervisory Circuits => System Supervisors/Reset => Supervisory Function |
| Description: | LM3822 - Precision Current Gauge ic With Internal Zero Ohm Sense Element And PWM Output, Package: Mini Soic, Pin Nb=8 |
| Company: | National Semiconductor Corporation |
| Datasheet: | Download LM3822MMX-1.0 datasheet File size : 272 kB |
| Request For quote: | Find where to buy LM3822MMX-1.0
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Datasheet text preview:
LM3822 Precision Current Gauge IC with Internal Zero Ohm Sense Element and PWM Output
July 2000
LM3822 Precision Current Gauge IC with Internal Zero Ohm Sense Element and PWM Output
General Description
The LM3822 Current Gauge provides easy to use precision current measurement with virtually zero insertion loss (typically 0.003). 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 Specifications
n Ultra low insertion loss (typically 0.003) n 2V to 5.5V supply range n ± 2% 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 50 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 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 1 mA for 1A part
Applications
n n n n Battery charge/discharge gauge Motion control diagnostics Power supply load monitoring and management Resettable smart fuse
Connection Diagram
DS101249-1
Top View LM3822 for High-Side Sensing
© 2000 National Semiconductor Corporation
DS101249
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LM3822
Ordering Information
Order No.* LM3822MM-1.0 LM3822MMX-1.0 LM3822MM-2.0 LM3822MMX-2.0 Sense Range Sampling Interval* 50 ms 50 ms 50 ms 50 ms Sensing Method High-side High-side High-side High-side NS Package Number MUA08A MUA08A MUA08A MUA08A Package Type MSOP-8 MSOP-8 MSOP-8 MSOP-8 Supplied As: Tape and Reel (1000 units/reel) Tape and Reel (3500 units/reel) Tape and Reel (1000 units/reel) Tape and Reel (3500 units/reel)
± 1.0A ± 1.0A ± 2.0A ± 2.0A
* Current is sampled over a fixed interval. The average current during this interval is indicated by the duty cycle of the PWM output during next interval.
Pin Description (High-Side, LM3822)
Pin 1 2 3 4 5 6 7 8 GND FLTR+ FLTR- SD TEST PWM SENSE- Name SENSE+, VDD Supply Ground. Filter input -- provides anti-aliasing for delta sigma modulator. Filter input. Shutdown input. Connected to VDD through a pull-up resistor for normal operation. When low, the LM3822 is put into a low current mode. Connect to GND for normal operation. Digital output indicates the current magnitude and direction. Low side of internal current sense. Function High side of internal current sense, also supply voltage.
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LM3822
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Absolute Maximum Supply Voltage Power Dissipation ESD Susceptibility (Note 3) Sense Current (peak, for 200 msec) (Note 4) Sink Current for PWM pin Maximum Junction Temperature 5.5V (Note 2) 1.5 kV 10A 1mA 150°C
Storage Temperature Lead Temperature (Soldering, 10 sec)
-65°C to +150°C 260°C
Operating Ratings (Note 1)
Input Voltage Sense Current (continuous) (Note 4) Junction Temperature Range 2.0V to 5.25V 5A -40°C to +85°C
Electrical Characteristics LM3822-1.0
Typical numbers are at 25°C and represent the most likely parametric norm. Specifications in standard type face are for TJ = 25°C and those with boldface type apply over full operating temperature ranges.
SENSE+VDD = 3.6V for the following specifications. Supply bypass capacitor is 1 µF and filter capacitor is 0.1 µF. Symbol IACC Parameter Average Current Accuracy (Note 7) 1.0A current Conditions Typ (Note 5) 1.0 0.98 / 0.96 1.02 / 1.04 en Effective Output Noise (rms) 2 Limit (Note 6) Units A A (min) A (max) mA
LM3822-2.0
SENSE+VDD = 3.6V for the following specifications. Supply bypass capacitor is 1 µF and filter capacitor is 0.1 µF. Symbol IACC Parameter Average Current Accuracy (Note 7) Effective Output Noise (rms) Conditions 2.0A current (Note 8) Typ (Note 5) 2.0 1.94 / 1.90 2.06 / 2.10 en 6 Limit (Note 6) Units A A (min) A (max) mA
Common Device Parameters
Unless otherwise specified, VDD = 3.6V for the following specifications. Supply bypass capacitor is 1 µF and filter capacitor is 0.1 µF. Symbol IQ1 IQ2 DRES tS Parameter Quiescent Current Quiescent Current PWM Resolution Sampling Time Conditions Normal Mode, SD = high Shutdown Mode, SD = low Typ (Note 5) 95 150 1.8 10 0.1 50 40 80 fP Frequency of PWM Waveform 20 12.5 25 VTH Threshold High Level for SD 1.3 1.8 Limit (Note 6) Units µA µA (max) µA µA (max) % ms ms (min) ms (max) Hz Hz (min) Hz (max) V V (min)
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