LTC5593IUH#PBF Linear Technology, LTC5593IUH#PBF Datasheet - Page 21

• Manufacturer Part Number: LTC5593IUH#PBF
• Manufacturer: Linear Technology

Specifications of LTC5593IUH#PBF

• Operating Supply Voltage: 3.3V
• Operating Temperature (min): -40C
• Operating Temperature Classification: Industrial
• Lead Free Status / Rohs Status: Compliant

For the RF inputs to be properly matched, the appropriate
LO signal must be applied to the LO input. A broadband
input match is realized with C1A = 22pF . The measured
input return loss is shown in Figure 4 for LO frequencies
of 2.4GHz, 3.0GHz and 3.6GHz. These LO frequencies
correspond to lower, middle and upper values in the LO
range. As shown in Figure 5, the RF input impedance is
dependent on LO frequency, although a single value of
C1A is adequate to cover the 2.3GHz to 4.0GHz RF band.
APPLICATIONS INFORMATION
channel-to-channel isolation at specific RF operation
frequency with minor impact to conversion gain, linearity
and noise performance. The channel-to-channel isola-
tion performance with different values of C8A is given in
Figure 4. When used, it should be located within 2mm of
Pin 2 for proper high frequency decoupling. The nominal
DC voltage on the CTA pin is 1.2V.
Figure 4. Channel-to-Channel Isolation vs C8 Values
10
15
20
25
30
55
50
45
40
35
30
0
5
2.0
2.2
2.2
Figure 5. RF Port Return Loss
2.3
2.4
2.6
RF FREQUENCY (GHz)
RF FREQUENCY (GHz)
2.4
2.8
3.0 3.2 3.4 3.6 3.8
2.5
2.6
LO = 2.4GHz
LO = 3GHz
LO = 3.6GHz
C8 OPEN
C8 = 2.2pF
C8 = 10pF
2.7
5593 F05
5593 F04
4.0
2.8
The RF input impedance and input reflection coefficient,
versus RF frequency, are listed in Table 1. The reference
plane for this data is Pin 1 of the IC, with no external
matching, and the LO is driven at 2.31GHz.
Table 1. RF Input Impedance and S11
(at Pin1, No External Matching, LO Input Driven at 2.31GHz)
LO Input
The LO input, shown in Figure 6, is connected to the pri-
mary winding of an integrated transformer. A 50Ω imped-
ance match from 2.1GHz to 3.4GHz is realized at the LO
port by adding a 1.5pF external series capacitor, C2. This
capacitor is also needed for DC blocking if the LO source
has DC voltage present, since the primary side of the LO
transformer is DC-grounded internally. The DC resistance
of the primary is approximately 4.1Ω. For LO frequency
FREQUENCY
(GHZ)
MIXER B
MIXER A
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
3.6
3.8
4.0
TO
TO
LTC5593
Figure 6. LO Input Schematic
IMPEDANCE
74.2 + j13.6
48.3 + j10.9
51.5 + j14.1
57.1 + j15.5
62.6 + j11.8
50.8 – j10.7
69.4 – j6.4
45.2 – j3.0
45.6 + j6.5
64.3 + j4.7
63.6 – j6.8
RF INPUT
BIAS
BIAS
MAG
0.22
0.17
0.06
0.08
0.11
0.14
0.16
0.15
0.13
0.13
0.11
ENB
ENA
I
SEL
LO
5593 F06
LTC5593
14
S11
18
17
16
C2
ANGLE
–146.0
–15.2
120.3
–23.2
–79.4
23.1
92.3
75.9
57.3
37.2
16.0
21
L4
LO
5593p