LTC5593IUH#PBF Linear Technology, LTC5593IUH#PBF Datasheet - Page 24

• 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

APPLICATIONS INFORMATION
LTC5593
Table 3. IF Output Impedance vs Frequency
Values of L1A and L2A are tabulated in Figure 1 for vari-
ous IF frequencies. The measured IF output return loss
for bandpass IF matching is plotted in Figure 10.
Performances of 470MHz IF output frequency with low
side LO injection using bandpass IF matching is shown
in Figure 11. The test circuit schematic and components
values are shown in Figure 1 with R2 open in this example.
The test conditions are: V
ENB = high, I
24
Figure 10. IF Output Return Loss with Bandpass Matching
FREQUENCY (MHz)
10
15
20
25
30
5
100 150
140
190
240
300
380
500
90
SEL
= low, T
150nH
L1, L2
200
L1, L2
56nH
250 300 350 400 450 500 550 600
IF FREQUENCY (MHz)
C
CC
= 25°C.
= 3.3V, V
IMPEDANCE (R
L1, L2
33nH
DIFFERENTIAL OUTPUT
291 || –j714 (2.5pF)
282 || –j463 (2.5pF)
274 || –j353 (2.4pF)
265 || –j278 (2.4pF)
252 || –j225 (2.4pF)
231 || –j177 (2.4pF)
227 || –j127 (2.5pF)
CCIF
L1, L2
22nH
5593 F10
= 3.3V, ENA =
IF
|| X
IF
(C
IF
))
Lowpass IF Matching
For IF frequencies below 90MHz, the inductance values
become unreasonably high and the lowpass topology
shown in Figure 12 is preferred. This topology also can
provide improved RF to IF and LO to IF isolation. V
is supplied through the center tap of the 4:1 transformer.
A lowpass impedance transformation is realized by shunt
Figure 11. Performances of 470MHz IF Using Bandpass Matching
3.1 TO 5.3V
V
CCIFA
Figure 12. IF Output with Lowpass Matching
27
25
23
21
19
17
15
13
11
29
5
9
7
2.2
IIP3
G
C
2.4
C6
22
2.6
L1A
RF FREQUENCY (MHz)
IFA
2.8
+
LTC5593
3.0
T1A
R2A
C9A
3.2
C5A
4:1
ISOLATION
CHANNEL
3.4
C8 = OPEN
C8 = 10pF
21
3.6
5593 F11
L2A
IFA
3.8
IFA
50
–
5593 F12
50
48
46
42
32
56
54
52
44
40
38
36
34
CCIFA
5593p