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TELCOM SEMICONDUCTOR, INC.

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5V PRECISION DATA ACQUISITION

SUBSYSTEMS

TC530

TC534

TC530EV Evaluation Kit

The TC530EV consists of a 4" x 6" pre-assembled circuit

board that connects to the serial port of any PC or dumb

design utility that calculates component and LOAD values

based on user input, and prints a finished circuit schematic.

Please contact your local TelCom representative for more

information, or point your web browser to http://www.telcom-

semi.com.

(2) Improper sequencing of the power supply inputs

sequence to occur in the internal state machines. It is

first. One method of insuring the correct power-up sequence

is to delay the analog supply using a series resistor and a

capacitor. See Figure 6, TC530/534 Typical Application.

(3) Decoupling capacitors, preferably a higher value elec-

trolytic or tantulum in parallel with a small ceramic or

tantalum, should be used liberally. This includes bypassing

the supply connections of all active components and the

voltage reference.

(4) Critical components should be chosen for stability and

Polypropylene or Polyphenelyne Sulfide (PPS) capacitors

(5) The inputs and integrator section are very high imped-

ance nodes. Leakage to or from these critical nodes can

contribute measurement error. A guard-ring should be used

to protect the integrator section from stray leakage.

(6) Circuit assemblies should be scrupulously clean to

prevent the presence of contamination from assembly,

handling, or the cleaning itself. Minutely conductive trace

contaminates, easily ignored in most applications, can ad-

versely affect the performance of high impedance circuits.

The input and integrator sections should be made as com-

pact and close to the TC53x as possible.

(7) Digital and other dynamic signal conductors should be

kept as far from the TC53x’s analog section as possible. The

microcontroller or other host logic should be kept quiet

during a measurement cycle. Background activites such as

keypad scanning, display refreshing, and power switching

can introduce noise.

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