SA9603C
TYPICAL APPLICATIONS
IntheApplicationCircuits(Figures1and2), thecomponentsrequiredforpowermetering
applications, are shown.
In Figure 1, a shunt resistor is used for current sensing. In this application, the circuitry
requires a +2.5V, 0V, -2.5V DC supply.
In the case of Figure 2, when using a current transformer for current sensing, a +5V, 0V
DC supply is sufficient for the circuit.
R1, R2 and RSH are the resistors defining the current level into the current sense input.
The values should be selected for an input current of 16µARMS into the SA9603C at rated
line current.
Values for RSH of less than 200µΩ should be avoided.
R1 = R2 = (IL/16µARMS) * RSH/2
Where IL
= Line current
RSH = Shunt resistor/termination resistor
R3, R6 and R4 set the current for the voltage sense input. The values should be selected
so that the input current into the voltage sense input (virtual ground) is set to 14µARMS
.
R7 defines all on-chip bias and reference currents. With R7 = 24kΩ, optimum conditions
are set.
XTAL is a colour burst TV crystal (f = 3.5795MHz) for the oscillator. The oscillator
frequency is divided down to 1.7897MHz on-chip to supply the A/D converters and digital
circuitry.
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sa m e s
SAMES [ SAMES ]
