Rainbow-electronics LM3813 User Manual

LM3812/LM3813Precision Current Gauge IC with Ultra Low Loss SenseElement and PWM OutputGeneral DescriptionThe LM3812/LM3813 Current Gauges provide eas

Product OperationThe current is sampled by the delta-sigma modulator, asillustrated in Figure 6. The pulse density output of the delta-sigma modulator

PWM Output and CurrentAccuracyOffsetThe PWM output is quantized to 1024 levels. Therefore, theduty cycle can change only in increments of 1/1024.There

Look-Up TablesThe following tables show how to convert the duty cycle ofthe PWM output to a current value, and vice versa. Thequantization error of1⁄2

TABLE 2. Duty Cycle to Current Conversion TableDuty Cycle(%)Sense Current(Amps)Duty Cycle(%)Sense Current(Amps)95.5 0.990 50.0 -0.00092.5 0.935 47.5 -

Physical Dimensions inches (millimeters)unless otherwise noted8-lead (0.150" Wide) Molded Small Outline PackageSee Ordering Information table for

Ordering InformationOrder No.#SenseRangeSamplingInterval*SensingMethodNSPackageNumber‡PackageType Supplied As:LM3812M-1.0±1A 50 ms High-side M08A SO-8

Absolute Maximum Ratings (Note 1)If Military/Aerospace specified devices are required,please contact the National Semiconductor Sales Office/Distribut

Electrical Characteristics (Continued)Common Device Parameters (Continued)Unless otherwise specified, VDD= 5.0V for the following specifications. Supp

Typical Performance Characteristics Supply bypass capacitor is 0.1 µF and filter capacitor is0.1 µF. (Continued)PWM Frequency vs Supply Voltage PWM Fr

Typical Performance Characteristics Supply bypass capacitor is 0.1 µF and filter capacitor is0.1 µF. (Continued)Current vs Duty Cycle Accuracy vs Supp

Typical Application CircuitsIn the application circuits, the 0.1 µF ceramic capacitorbetween pins 1 and 8 is used for bypassing, and the 0.1µF ceramic

Typical Application Circuits In the application circuits, the 0.1 µF ceramic capacitor between pins 1 and 8is used for bypassing, and the 0.1 µF ceram

Typical Application Circuits In the application circuits, the 0.1 µF ceramic capacitor between pins 1 and 8is used for bypassing, and the 0.1 µF ceram