LT5520EUF Linear Technology, LT5520EUF Datasheet - Page 7

• Manufacturer Part Number: LT5520EUF
• Description: IC MIXER UPCONV 1.3-2.3GHZ 16QFN
• Manufacturer: Linear Technology
• Series: LT5520r

Specifications of LT5520EUF

• Rf Type: General Purpose
• Frequency: 1.3GHz ~ 2.3GHz
• Number Of Mixers: 1
• Gain: -1dB
• Noise Figure: 15dB
• Secondary Attributes: Up Converter
• Current - Supply: 70mA
• Voltage - Supply: 4.5 V ~ 5.25 V
• Package / Case: 16-WQFN Exposed Pad
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIO S I FOR ATIO
Table 1 lists the differential IF input impedance and reflec-
tion coefficient for several frequencies. A 4:1 balun can be
used to transform the impedance up to about 50 .
Table 1. IF Input Differential Impedance
LO Input Port
The simplified circuit for the LO buffer input is shown in
Figure 4. The LO buffer amplifier consists of high-speed
limiting differential amplifiers, optimized to drive the mixer
quad for high linearity. The LO
driven differentially; however, they are intended to be
driven by a single-ended source. An internal resistor
connected across the LO
broadband 50 impedance match. Because of the resis-
tive match, a DC voltage at the LO input is not recom-
mended. If the LO signal source output is not AC coupled,
then a DC blocking capacitor should be used at the LO
input.
Frequency
50
IF
(MHz)
IN
140
170
240
360
500
10
44
70
Figure 3. IF Input with External Matching
4:1
T1
Differential Input
C1
C2
10.1 + j0.117
10.1 + j0.476
10.1 + j0.751
U
10.2 + j1.47
10.2 + j1.78
10.2 + j2.53
10.2 + j3.81
10.2 + j5.31
Impedance
C3
100
0.1%
100
0.1%
U
+
2
3
and LO
LT5520
+
18mA
18mA
and LO
W
–
0.663
0.663
0.663
0.663
0.663
0.663
0.663
0.663
inputs provides a
Mag
Differential S11
V
–
CC
ports can be
U
Angle
180
179
178
177
176
174
171
167
5520 F03
Though the LO input is internally 50 matched, there may
be some cases, particularly at higher frequencies or with
different source impedances, where a further optimized
match is desired. Table 2 includes the single -ended input
impedance and reflection coefficient vs frequency for the
LO input for use in such cases.
Table 2. Single-Ended LO Input Impedance
RF Output Port
An internal RF transformer, shown in Figure 5, reduces the
mixer-core impedance to provide an impedance of 50
across the RF
tested with the outputs configured for single-ended opera-
tion, as shown in the Figure 5; however, the outputs can be
used differentially as well. A center-tap in the transformer
provides the DC connection to the mixer core and the
transformer provides DC isolation at the RF output. The
RF
secondary windings of the transformer, thus a DC voltage
should not be applied across these pins.
Frequency
+
(MHz)
1300
1500
1700
1900
2100
2300
2500
2700
and RF
LO
50
IN
–
+
pins are connected together through the
14
15
and RF
V
LT5520
CC
LO
LO
Figure 4. LO Input Circuit
+
–
56.5 – j17.9
54.9 – j18.8
53.7 – j18.8
62.8 – j9.14
62.2 – j11.4
61.5 – j13.4
60.0 – j15.2
58.4 – j16.9
Impedance
–
Input
pins. The LT5520 is designed and
85
5pF
5pF
220
220
0.139
0.148
0.157
0.164
0.172
0.176
0.182
0.182
Mag
LT5520
5520 F04
S11
Angle
–30.9
–37.1
– 42.4
– 48.9
–54.7
–60.4
–65.1
–68.5
7
5520f