SA9103C

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TYPICAL APPLICATIONS

In the Application Circuits (Figures 1 and 2), the components required for power metering

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.

The most important external components for the SA9103C integrated circuit are:

C

converters. The value of these capacitors is 560pF. The actual values determine the

signal to noise and stability performance. The tolerances should be within ±10%.

C

The actual values are uncritical. Values smaller than 0.5nF and larger than 5nF should

be avoided.

R

The values should be selected for an input current of 16µA into the SA9103C at rated line

current.

Values for RSH of less than 200µ

Ω should be avoided.

R

Where

I

L

= Line current

RSH

= Shunt resistor/termination resistor

R

so that the input current into the voltage sense input (virtual ground) is set to 14µA.

R

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.