PM9603AP

sames

5/18

The current sense input requires a differential approach to cater for precision across

the dynamic range. It is therefore important that the PC board layout of the branches

to the sensing element, are as symmetrical as possible and the loop area is kept to

a minimum.

The most important external components for the SA9603B integrated circuit are:

R

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

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

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 14µA

R

With R

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 and supplies the A/D converters

and the digital circuitry.

7. Demonstration Software

Software which runs under Windows 3.1 and Windows 95 is provided with each

evaluation module. See README.TXT on the diskette supplied for the installation

instructions.

8. Sample C source code

The following software demonstrates how to synchronize the reading of the registers

to the SA9603B's internal offset cancellation scheme. The software is also available

on the SAMES Internet web pages.