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MTC20154

Linearity of ATU-C-TX

Linearity of the TX is defined by the IM3 product of two sinusoidal signals with frequencies f1 and f2 and

each with 0.25 Vpd amplitude (-6 dB FS) at the output of the pre-driver for the case of a total AGC = 0 dB.

Table 18. Linearity of ATU-C-TX

Table 19. Linearity of ATU-R-TX

Power Supply Rejection

The noise on the power supplies for the TX-path must be lower than the following: < 50 mVrms in band

white noise for AVDD.

< 15 mVrms in band white noise for Pre-driver AVDD.

Voltage Controlled Crystal Oscillator

A voltage controlled crystal oscillator driver is integrated in the MTC20154. Two nominal frequencies can

be used: 35.328 MHz or 17.664 MHz. The quartz crystal is connected between the pins XTALI and XTA-

LO.

The principle of the VCXO control is depicted on the figure beside.

Figure 8. Principle of the VCXO control (ATU-R)

f1 (0.25 Vpd)

f2 (0.25 Vpd)

300 kHz

200 kHz

500 kHz

400 kHz

700 kHz

600 kHz

S/IM3

(AGC = 0 dB)

59.5 dB @100 kHz

53.5 dB @400 kHz

43.5 dB @700 kHz

42.5 dB @800 kHz

59.5 dB @300 kHz

45.0 dB @600 kHz

48.0 dB @500 kHz

42.5 dB @800 kHz

f1 (0.25 Vpd)

80 k

f2 (0.25 Vpd)

70 k

S/IM3 (AGC = 0 dB)

59.5 dB (60 k/90 k)

AVDD

AVDD

AVDD/22 -> AVDD/2

VCOCAP

IVCO

MTC-20154

Ron=200

Ω

VCXOUT

AGND

R1

Rref

-15V

XTAL1

XTAL0

Ct

500k

Ω

+/- 30%

DAC

CTRLIN

8

Freq.

doubler

MUX

Clock