7

KESTX01

y)

p

OP

OPb

XTAL2

XTAL1

Rs

CLK

C

COMPONENT LIST at 433.92MHz

COMPONENTS

FUNCTION

VALUE

UNITS

R1

OUTPUT POWER CONTROL

2.0

k

Ω

R2

PLL LOOP FILTER

4.7

k

Ω

C1

ANTENNA TUNING

APPLICATION

pF

DEPENDENT

L1 and L2

ANTENNA TUNING

APPLICATION

nH

DEPENDENT

C2

PLL LOOP FILTER

220

pF

C3

PLL LOOP FILTER

10

nF

X1

PARALLEL RESONANT CRYSTAL

6.78

MHz

C4

CRYSTAL OSCILLATOR

18

pF

C5

CRYSTAL OSCILLATOR

18

pF

Note:

The value of C1 is split between two capacitors to aid in balancing the antenna loop reducing the level of the second

harmonic

TESTABILITY REQUIREMENTS

This section is a summary of the observability and control-

lability requirements identified to simplify the production test

requirements of the device.

1. Ability to directly drive the XTAL oscillator from the tester (no

crystal). The XTAL2 pin allows direct drive of the oscillator with

an external clock source as shown in Figure 7. Typically a

200mVpk clock signal is AC coupled to produce differential

output on OP and OPb. (C=10nF, R s (Source) <5k

Ω)

Figure 7 Direct drive of crystal oscillator

2.

Control of the VCO frequency is obtained via the LF1

signal pin. The output of the dividers is tested by measuring

the DC current output of the charge pump (with XTAL2 held

at V

CC

).

3.

DC operation of the power amplifier is observed by

measuring the current through the open collector outputs OUT

and OUTB. The VCO input to the power amplifier is disabled

with VCOTST tied to V

CC

and the bias current being measured

with DATA tied to V

CC

. Toggling DATA input will modulate the

bias current in the power amplifier.