SA9602M

sames

11/16

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.

The most important external components for the SA9602M integrated circuit are:

R

The values should be selected for an input current of 16µA

maximum 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. R

Any change to R

affect the output quadratically (i.e.: R

The formula for calculating the output frequency is given below:

f

= 11.16 * FOUTX *

FOSC

*

I

LED

3.58MHz

I

R

2

Where FOUTX

= Frequency for selected rated condition

FOSC

= Oscillator frequency (2MHz ...... 4MHz)

I

I

= Input current for current input (16µA

I

V

= Input current for voltage input (14µA

I

R

= Reference current

(typically 50µA)

XTAL is a colour burst TV crystal (f = 3.5795 MHz) for the oscillator. The oscillator

frequency is divided down to 1.7897 MHz on-chip, to supply the digital circuitry and the

A/D converters.