5

MRFIC1803

MOTOROLA RF DEVICE DATA

Frequency (MHz)

RF Output

LO Input

LO Output

1500

22.07 –j11.36

41.98 +j22.31

20.09 +j31.15

1550

21.74 –j4.69

50.60 +j9.80

26.39 +j40.79

1600

22.28 +j2.16

41.93 –j0.07

37.63 +j52.47

1650

24.01 +j8.25

32.74 +j3.32

56.16 +j63.47

1700

26.64 +J14.13

28.78 +j11.39

87.97 +j67.31

1750

30.83 +j20.11

28.98 +j21.04

131.33 +j40.34

1800

36.39 +j25.30

32.13 +j30.26

137.85 –j16.48

1850

43.92 +j29.26

37.68 +j40.38

103.88 –j50.81

1900

54.37 +j30.98

48.31 +j54.15

69.58 –j53.97

1950

65.34 +j28.57

68.80 +j70.87

50.13 –j46.24

2000

75.30 +j21.12

118.18 +j86.46

38.97 –j36.86

2050

81.19 +j8.43

220.83 +j17.19

32.08 –j27.58

2100

80.22 –j4.24

148.91 –j120.77

28.43 –j19.86

2150

74.20 –j14.00

58.50 –j105.11

26.56 –j12.82

2200

65.50 –j19.72

27.23 –j71.51

26.03 –j5.89

2250

57.40 –j21.38

17.22 –j50.26

26.73 –j0.03

2300

50.59 –j20.61

13.00 –j35.19

28.46 +j5.10

2350

44.53 –j18.16

10.95 –j22.96

30.88 +j9.86

2400

40.24 –j14.78

10.23 –j13.58

33.75 +j13.92

2450

37.73 –j10.54

10.20 –j5.32

37.50 +j17.32

2500

36.38 –j6.72

10.62 +j2.90

42.00 +j20.34

Table 1. Selected Device Impedances

DESIGN AND APPLICATIONS INFORMATION

The MRFIC1803 combines a single–balanced FET mix-

er with an LO pre–amp and an exciter amplifier to form a

self–contained upconverter. The device is usable from RF

frequencies of 1.7 to 2.5 GHz and at IF frequencies of 70

to 325 MHz. The design is optimized for low side injection

in hetrodyne transmitter applications. In the upconversion

process, modulation is imparted to an IF carrier which is

converted to the RF transmit frequency by a mixer. By DC

coupling the IF input, the device can be used for simple

on–off keying (OOK) or bi–phase shift keying (BPSK) ap-

plications with no IF.

The MRFIC1803 design minimizes the need for off–chip

components. An active balun is employed at the IF input

and provides an excellent broadband 50

W match over the

full range of IF frequencies. The LO quadrature divider is

passive and internal to the device. The LO buffer amplifier

is equipped with a diversity switch which switches the am-

plified LO signal to the LO output pin during RECEIVE

mode. The –5 dBm LO output is the appropriate level to

drive the MRFIC1804 for 1.8 GHz applications or the

MRFIC2401 for 2.4 GHz applications.

As shown in Figure 1, the device is easy to use with

minimal off–chip components. More or less bypassing of

the control and supply lines may be required depending

on board layout and shielding. Careful layout of the RF

frequency portions of the board is critical to successful

implementation. Controlled impedance lines must be used

and any off–chip components must be mounted as close to

the IC as possible. The applications circuit was used to

gather the information displayed in the typical characteris-

tics curves. Since the MRFIC1803 design was optimized

for the 1.7 to 1.9 GHz frequency range, improved perfor-

mance can be had with some off–chip matching at fre-

quencies outside this range. In particular, matching of the

LO port will supply higher LO drive and improve conver-

sion gain. At the RF output, either better gain or better 1dB

compression can be had with external matching.

Filtering is generally required in the upconversion pro-

cess to reduce image and LO radiation. To minimize pin

count, this filtering is accomplished external to the device

at the exciter output. For the frequency ranges of applica-

tion, two and three pole ceramic surface filters are avail-

able at reasonable cost and with less than 2 dB of loss.

EVALUATION BOARDS

Evaluation boards are available for RF Monolithic Inte-

grated Circuits by adding a “TF” suffix to the device type.

For a complete list of currently available boards and ones

in development for newly introduced product, please con-

tact your local Motorola Distributor or Sales Office.