LT5520EUF [Linear]
1.3GHz to 2.3GHz High Linearity Upconverting Mixer; 为1.3GHz至2.3GHz高线性度上变频混频器
| 型号： | LT5520EUF |
| 厂家： | 
Linear |
| 描述： | 1.3GHz to 2.3GHz High Linearity Upconverting Mixer |
| 文件： | 总12页 (文件大小：186K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LT5520
1.3GHz to 2.3GHz
High Linearity
Upconverting Mixer
U
FEATURES
DESCRIPTIO
The LT®5520 mixer is designed to meet the high linearity
requirements of wireless and cable infrastructure trans-
mission applications. A high-speed, internally matched,
LO amplifier drives a double-balanced mixer core, allow-
ing the use of a low power, single-ended LO source. An RF
output transformer is integrated, thus eliminating the
need for external matching components at the RF output,
whilereducingsystemcost, componentcount, boardarea
and system-level variations. The IF port can be easily
matched to a broad range of frequencies for use in many
different applications.
■
Wide RF Output Frequency Range: 1.3GHz
to 2.3GHz
■
15.9dBm Typical Input IP3 at 1.9GHz
■
On-Chip RF Output Transformer
■
No External LO or RF Matching Required
■
Single-Ended LO and RF Operation
■
Integrated LO Buffer: –5dBm Drive Level
■
Low LO to RF Leakage: – 41dBm Typical
■
Wide IF Frequency Range: DC to 400MHz
■
Enable Function with Low Off-State Leakage Current
■
Single 5V Supply
Small 16-Lead QFN Plastic Package
■
The LT5520 mixer delivers 15.9dBm typical input 3rd
order intercept point at 1.9GHz with IF input signal levels
of –10dBm. The input 1dB compression point is typically
4dBm. The IC requires only a single 5V supply.
U
APPLICATIO S
■
Wireless Infrastructure
■
Cable Downlink Infrastructure
■
, LTC and LT are registered trademarks of Linear Technology Corporation.
Point-to-Point Data Communications
High Linearity Frequency Conversion
■
U
TYPICAL APPLICATIO
5V
DC
RF Output Power and Output IM3 vs
IF Input Power (Two Input Tones)
1µF
1000pF
39nH
10
0
EN
BIAS
V
V
CC2
V
CC3
CC1
–10
10pF
100Ω
100Ω
BPF
P
OUT
220pF
15pF
–20
–30
–40
–50
–60
–70
–80
–90
4:1
IF
INPUT
+
+
RF
RF
IF
IF
RF
OUTPUT
PA
–
–
P
= –5dBm
= 1760MHz
= 140MHz
= 141MHz
= 1900MHz
220pF
LO
BPF
f
LO
IM3
f
IF1
IF2
RF
f
f
T
= 25°C
A
GND
–16
–12
–8
–4
0
4
5pF
5pF
85Ω
IF INPUT POWER (dBm/TONE)
+
–
LT5520
LO
LO
(OPTIONAL)
5520 • F01b
5520 F01
LO INPUT
–5dBm
Figure 1. Frequency Conversion in Wireless Infrastructure Transmitter
5520f
1
LT5520
W W U W
U
W
U
ABSOLUTE AXI U RATI GS
(Note 1)
PACKAGE/ORDER I FOR ATIO
TOP VIEW
ORDER PART
NUMBER
Supply Voltage ....................................................... 5.5V
Enable Voltage ............................. –0.3V to (VCC + 0.3V)
LO Input Power (Differential).............................. 10dBm
RF+ to RF– Differential DC Voltage...................... ±0.13V
RF Output DC Common Mode Voltage ......... –1V to VCC
IF Input Power (Differential) ............................... 10dBm
IF+, IF– DC Currents.............................................. 25mA
LO+ to LO– Differential DC Voltage .......................... ±1V
LO Input DC Common Mode Voltage............ –1V to VCC
Operating Temperature Range .................–40°C to 85°C
Storage Temperature Range ................. –65°C to 125°C
Junction Temperature (TJ).................................... 125°C
16 15 14 13
GND
GND
1
2
3
4
12
11
10
9
LT5520EUF
+
+
RF
RF
IF
17
–
–
IF
GND
GND
5
6
7
8
UF PART
MARKING
UF PACKAGE
16-LEAD (4mm × 4mm) PLASTIC QFN
EXPOSED PAD IS GND (PIN 17),
MUST BE SOLDERED TO PCB
5520
TJMAX = 125°C, θJA = 37°C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
MHz
IF Input Frequency Range
LO Input Frequency Range
RF Output Frequency Range
DC to 400
900 to 2700
1300 to 2300
MHz
MHz
1900MHz Application: VCC = 5VDC, EN = High, TA = 25°C, IF input = 140MHz at –10dBm, LO input = 1.76GHz at –5dBm, RF output
measured at 1900MHz, unless otherwise noted. Test circuit shown in Figure 2. (Notes 2, 3)
PARAMETER
CONDITIONS
Z = 50Ω, with External Matching
MIN
TYP
20
MAX
UNITS
dB
IF Input Return Loss
LO Input Return Loss
RF Output Return Loss
LO Input Power
O
Z = 50Ω
O
16
dB
Z = 50Ω
O
20
dB
–10 to 0
–1
dBm
dB
Conversion Gain
Input 3rd Order Intercept
Input 2nd Order Intercept
LO to RF Leakage
–10dBm/Tone, ∆f = 1MHz
15.9
45
dBm
dBm
dBm
dBm
dBm
–10dBm, Single-Tone
–41
–35
4
LO to IF Leakage
Input 1dB Compression
IF Common Mode Voltage
Noise Figure
Internally Biased
Single Side Band
1.77
15
V
DC
dB
DC ELECTRICAL CHARACTERISTICS
(Test Circuit Shown in Figure 2) VCC = 5VDC, EN = High , TA = 25°C (Note 3), unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Enable (EN) Low = Off, High = On
Turn-On Time (Note 4)
Turn-Off Time (Note 4)
Input Current
2
6
1
µs
µs
V
= 5V
10
µA
ENABLE
DC
5520f
2
LT5520
DC ELECTRICAL CHARACTERISTICS
(Test Circuit Shown in Figure 2) VCC = 5VDC, EN = High , TA = 25°C (Note 3), unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Enable = High (On)
Enable = Low (Off)
Power Supply Requirements (V
Supply Voltage
3
V
V
DC
DC
0.5
)
CC
4.5 to 5.25
V
DC
Supply Current
V
= 5V
60
1
70
mA
CC
DC
Shutdown Current
EN = Low
100
µA
Note 1: Absolute Maximum Ratings are those values beyond which the life
Note 3: Specifications over the –40°C to 85°C temperature range are
of a device may be impaired.
Note 2: External components on the final test circuit are optimized for
assured by design, characterization and correlation with statistical process
controls.
operation at f = 1900MHz, f = 1.76GHz and f = 140MHz.
Note 4: Turn-On and Turn-Off times are based on the rise and fall times of
the RF output envelope from full power to –40dBm with an IF input power
of –10dBm.
RF
LO
IF
U W
TYPICAL PERFOR A CE CHARACTERISTICS
(Test Circuit Shown in Figure 2)
Supply Current
Shutdown Current
vs Supply Voltage
vs Supply Voltage
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
66
64
62
60
58
56
54
52
50
T
= 85°C
A
T
= 25°C
A
T
= 85°C
A
T
= –40°C
A
T
= 25°C
A
T
= –40°C
A
5.25
5.25
4.0
4.25
4.5
4.75
5.0
5.5
4.0
4.25
4.5
4.75
5.0
5.5
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
5520 • GO2
5520 • GO1
VCC = 5VDC, EN = High, TA = 25°C, IF input = 140MHz at –10dBm, LO input = 1.76GHz at –5dBm, RF output measured at 1900MHz,
unless otherwise noted. For 2-tone inputs: 2nd IF input = 141MHz at –10dBm. (Test Circuit Shown in Figure 2.)
Conversion Gain and SSB Noise
Figure vs RF Output Frequency
LO-RF Leakage
IIP3 and IIP2
vs RF Output Frequency
vs RF Output Frequency
55
50
45
40
35
30
25
20
15
10
5
18
16
14
12
10
8
32
30
28
26
24
22
20
18
16
14
12
–10
–20
–30
–40
–50
–60
HIGH SIDE LO
LOW SIDE LO
IIP2
LOW SIDE LO
SSB NF
HIGH SIDE LO
HIGH SIDE LO
LOW SIDE LO
6
4
IIP3
LOW SIDE LO
2
GAIN
0
LOW SIDE AND HIGH SIDE LO
HIGH SIDE LO
–2
–4
1300 1500 1700 1900 2100 2300 2500
1300 1500 1700 1900 2100 2300 2500
1300 1500 1700 1900 2100 2300 2500
RF OUTPUT FREQUENCY (MHz)
RF OUTPUT FREQUENCY (MHz)
RF OUTPUT FREQUENCY (MHz)
5520 • GO3
5520 • GO4
5520 • GO5
5520f
3
LT5520
U W
TYPICAL PERFOR A CE CHARACTERISTICS
VCC = 5VDC, EN = High , TA = 25°C, IF input = 140MHz at –10dBm, LO input = 1.76GHz at –5dBm, RF output measured at 1900MHz,
unless otherwise noted. For 2-tone inputs: 2nd IF Input = 141MHz at –10dBm. (Test Circuit Shown in Figure 2.)
Conversion Gain and SSB Noise
Figure vs LO Input Power
LO-RF Leakage
vs LO Input Power
IIP3 and IIP2 vs
LO Input Power
20
18
16
14
12
10
8
16
14
12
10
8
50
45
40
35
30
25
20
15
10
5
–10
–20
–30
–40
–50
–60
T
= 25°C
A
T
= 85°C
A
SSB NF
T
= 85°C
A
T
= –40°C
A
IIP2
T
= –40°C
A
T
= 25°C
A
6
T
= –40°C
A
IIP3
4
T
= 25°C, T = –40°C
A
A
GAIN
T
= 25°C
A
6
2
T
= 85°C
T = 25°C
A
A
T
= –40°C
T
= 85°C
A
A
4
0
2
–2
–4
T
= 85°C
A
0
0
–16
0
4
0
4
–16
–12
–8
–4
0
4
–12
–8
–4
–16
–12
–8
–4
LO INPUT POWER (dBm)
LO INPUT POWER (dBm)
LO INPUT POWER (dBm)
5520 • G06
5520 • G07
5520 • G08
IIP3 and IIP2 vs
LO Input Power
RF Output Power and Output IM3 vs
IF Input Power (Two Input Tones)
RF Output Power and Output IM2 vs
IF Input Power (Two Input Tones)
50
45
40
35
30
25
20
15
10
5
10
0
10
0
LOW SIDE LO
T
= –40°C
A
T
= –40°C
A
–10
–20
–30
–40
–50
–60
–70
–80
–90
–10
–20
–30
–40
–50
–60
–70
–80
IIP2
IIP3
T
= 25°C
T
= 85°C
A
HIGH SIDE LO
A
T
= 25°C
A
T
= 85°C
A
P
OUT
P
OUT
T
= –40°C
A
HIGH SIDE LO
LOW SIDE LO
T
= 85°C
T
= –40°C
A
A
IM2
T
= 25°C
T
= 85°C
A
IM3
A
0
0
4
0
4
–16
–12
–8
–4
–16
–12
–8
–4
0
4
–16
–12
–8
–4
LO INPUT POWER (dBm)
IF INPUT POWER (dBm/TONE)
IF INPUT POWER (dBm/TONE)
5520 • G11
5520 • G09
5520 • G10
IF, LO and RF Port Return Loss
vs Frequency
Conversion Gain, IIP3 and IIP2
vs Supply Voltage
Conversion Gain vs IF Input
Power (One Input Tone)
50
45
40
35
30
25
20
15
10
5
0
–5
8
7
4
3
LOW SIDE LO
HIGH SIDE LO
6
2
IIP2
T
= –40°C
5
1
A
–10
–15
–20
–25
4
0
T
= 25°C
A
3
–1
–2
–3
–4
–5
–6
IIP3
T
= 85°C
2
A
HIGH SIDE LO
LOW SIDE LO
LO PORT
1
0
GAIN
RF PORT
IF PORT
–1
–2
LOW SIDE AND HIGH SIDE LO
0
5.5
0
1000 1500 2000 2500 3000
4.0
4.25
4.5
SUPPLY VOLTAGE (V)
4.75
5.0
5.25
0
4
500
–16
–12
–8
–4
FREQUENCY (MHz)
IF INPUT POWER (dBm)
5520 • G14
5520 • G12
5520 • G13
5520f
4
LT5520
U
U
U
PI FU CTIO S
GND (Pins 1, 4, 9, 12, 13, 16): Internal Grounds. These
pins are used to improve isolation and are not intended as
DC or RF grounds for the IC. Connect these pins to low
impedance grounds for best performance.
IF+, IF– (Pins 2, 3): Differential IF Signal Inputs. A differ-
ential signal must be applied to these pins through DC
blockingcapacitors.Thepinsmustbeconnectedtoground
with100Ω resistors(thegroundsmusteachbecapableof
sinking about 18mA). For best LO leakage performance,
these pins should be DC isolated from each other. An
impedance transformation is required to match the IF
input to the desired source impedance (typically 50Ω or
75Ω).
in Figure 2. The 1000pF capacitor should be located as
close to the pins as possible.
VCC3 (Pin 8): Power Supply Pin for the Internal Mixer.
Typical current consumption is about 36mA. This pin
should be externally connected to VCC through an induc-
tor. A 39nH inductor is used in Figure 2, though the value
is not critical.
RF–, RF+ (Pins 10, 11): Differential RF Outputs. One pin
maybeDCconnectedtoalowimpedancegroundtorealize
a 50Ω single-ended output. No external matching compo-
nents are required. A DC voltage should not be applied
acrossthesepins,astheyareinternallyconnectedthrough
a transformer winding.
EN(Pin5): EnablePin. Whentheappliedvoltageisgreater
than 3V, the IC is enabled. When the applied voltage is less
than 0.5V, the IC is disabled and the DC current drops to
about 1µA.
LO+, LO– (Pins 14, 15): Differential Local Oscillator In-
puts. The LT5520 works well with a single-ended source
driving the LO+ pin and the LO– pin connected to a low
impedanceground.Noexternalmatchingcomponentsare
required. An internal resistor is connected across these
pins; therefore, a DC voltage should not be applied across
the inputs.
VCC1 (Pin 6): Power Supply Pin for the Bias Circuits.
Typical current consumption is about 2mA. This pin
should be externally connected to VCC and have appropri-
ate RF bypass capacitors.
GROUND (Pin 17, Exposed Pad): DC and RF ground
return for the entire IC. This must be soldered to the
printed circuit board low impedance ground plane.
VCC2 (Pin 7): Power Supply Pin for the LO Buffer Circuits.
Typical current consumption is about 22mA. This pin
should have appropriate RF bypass capacitors as shown
W
BLOCK DIAGRA
BACKSIDE
+
–
GROUND GND
RF
11
RF
10
GND
9
17
12
13
14
GND
5pF
85Ω
5pF
8
V
CC3
HIGH SPEED
LO BUFFER
+
10pF
LO
DOUBLE-
BALANCED
MIXER
–
15
16
LO
V
6
5
CC1
BIAS
GND
EN
7
1
2
3
4
5520 BD
+
–
V
GND
IF
IF
GND
CC2
5520f
5
LT5520
TEST CIRCUIT
LO
IN
1760MHz
16
15
–
14
+
13
REF DES
C1, C2
C3
VALUE
220pF
15pF
SIZE
0402
0402
0402
0603
0402
PART NUMBER
GND
GND
LO
LO
GND
GND
1
2
3
4
12
11
IF
R1
IN
140MHz
AVX 04023C221KAT2A
AVX 04023A150KAT2A
AVX 04023A102KAT2A
Taiyo Yuden LMK107BJ105MA
Toko LL1005-FH39NJ
IRC PFC-W0603R-03-10R1-B
M/A-COM ETC4-1-2
C1
C2
T1
1
5
4
+
+
RF
IF
2
3
LT5520
C3
C4
1000pF
1µF
10
9
RF
OUT
1900MHz
–
–
IF
RF
C5
R2
GND
CC3
GND
EN
5
L1
39nH
V
V
CC2
V
CC1
6
RF
GND
7
8
R1, R2
T1
100Ω, 0.1% 0603
4:1 SM-22
0.018" ER = 4.4
EN
L1
0.062"
0.018"
DC
GND
V
CC
C5
C4
5520 TC01
Figure 2. Test Schematic for the LT5520
U
W
U U
APPLICATIO S I FOR ATIO
The LT5520 consists of a double-balanced mixer, a high-
performance LO buffer, and bias/enable circuits. The RF
and LO ports may be driven differentially; however, they
are intended to be used in single-ended mode by connect-
ing one input of each pair to ground. The IF input ports
must be DC-isolated from the source and driven differen-
tially. The IF input should be impedance-matched for the
desired input frequency. The LO input has an internal
broadband 50Ω match with return loss better than 10dB
at frequencies up to 3000MHz. The RF output band ranges
from 1300MHz to 2300MHz, with an internal RF trans-
former providing a 50Ω impedance match across the
band. Low side or high side LO injection can be used.
resistors with 0.1%, tolerance are recommended. If LO
leakage is not a concern, then lesser tolerance resistors
can be used. The symmetry of the layout is also important
for achieving optimum LO isolation.
The capacitors shown in Figure 3, C1 and C2, serve two
purposes. They provide DC isolation between the IF+ and
IF– ports, thus preventing DC interactions that could
cause unpredictable variations in LO leakage. They also
improve the impedance match by canceling excess induc-
tance in the package and transformer. The input capacitor
value required to realize an impedance match at desired
frequency, f, can be estimated as follows:
1
C1 = C2 =
IF Input Port
(2πf)2(LIN +LEXT
)
The IF inputs are connected to the emitters of the double-
balanced mixer transistors, as shown in Figure 3. These
pins are internally biased and an external resistor must be
connected from each IF pin to ground to set the current
through the mixer core. The circuit has been optimized to
work with 100Ω resistors, which will result in approxi-
mately 18mA of DC current per side. For best LO leakage
performance, the resistors should be well matched; thus
where; f is in units of Hz, LIN and LEXT are in H, and C1, C2
are in farad. LIN is the differential input inductance of the
LT5520,andisapproximately1.67nH.LEXT representsthe
combined inductances of differential external compo-
nents and transmission lines. For the evaluation board
shown in Figure 10, LEXT = 4.21nH. Thus, for f = 140MHz,
the above formula gives C1 = C2 = 220pF.
5520f
6
LT5520
U
W U U
APPLICATIO S I FOR ATIO
5pF
+
LO
LO
100Ω
0.1%
IN
14
50Ω
C1
18mA
220Ω
220Ω
T1
4:1
2
IF
IN
50Ω
V
85Ω
CC
C3
V
CC
5pF
3
–
LO
18mA
LT5520
15
C2
100Ω
0.1%
LT5520
5520 F03
5520 F04
Figure 3. IF Input with External Matching
Figure 4. LO Input Circuit
Though the LO input is internally 50Ω 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 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 50Ω.
Table 1. IF Input Differential Impedance
Frequency
(MHz)
Differential Input
Impedance
Differential S11
Mag
Angle
180
179
178
177
176
174
171
167
10
44
10.1 + j0.117
10.1 + j0.476
10.1 + j0.751
10.2 + j1.47
10.2 + j1.78
10.2 + j2.53
10.2 + j3.81
10.2 + j5.31
0.663
0.663
0.663
0.663
0.663
0.663
0.663
0.663
Table 2. Single-Ended LO Input Impedance
Frequency
(MHz)
Input
Impedance
S11
Mag
0.139
0.148
0.157
0.164
0.172
0.176
0.182
0.182
Angle
–30.9
–37.1
–42.4
–48.9
–54.7
–60.4
–65.1
–68.5
70
140
170
240
360
500
1300
1500
1700
1900
2100
2300
2500
2700
62.8 – j9.14
62.2 – j11.4
61.5 – j13.4
60.0 – j15.2
58.4 – j16.9
56.5 – j17.9
54.9 – j18.8
53.7 – j18.8
LO Input Port
The simplified circuit for the LO buffer input is shown in
Figure 4. The LO buffer amplifier consists of high-speed
limitingdifferentialamplifiers,optimizedtodrivethemixer
quad for high linearity. The LO+ and LO– ports can be
driven differentially; however, they are intended to be
driven by a single-ended source. An internal resistor
connected across the LO+ and LO– inputs provides a
broadband 50Ω 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.
RF Output Port
AninternalRFtransformer, showninFigure5, reducesthe
mixer-core impedance to provide an impedance of 50Ω
across the RF+ and RF– pins. The LT5520 is designed and
testedwiththeoutputsconfiguredforsingle-endedopera-
tion, asshownintheFigure5;however, theoutputscanbe
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+ and RF– pins are connected together through the
secondary windings of the transformer, thus a DC voltage
should not be applied across these pins.
5520f
7
LT5520
U
W
U U
APPLICATIO S I FOR ATIO
TheimpedancedatafortheRFoutput,listedinTable3,can
be used to develop matching networks for different load
impedances.
The performance was evaluated with the input tuned for
each of these frequencies and the results are summarized
in Figures 6-8. The same IF input balun transformer was
used for all measurements. In each case, the LO input
frequency was adjusted to maintain an RF output fre-
quency of 1900 MHz.
Table 3. Single-Ended RF Output Impedance
Frequency
(MHz)
Input
Impedance
S11
Mag
Angle
94.7
78.4
68.0
88.9
148
1300
1500
1700
1900
2100
2300
2500
2700
26.9 + j38.2
44.2 + j35.7
53.9 + j20.6
49.5 + j7.97
42.8 + j4.14
38.9 + j5.41
38.7 + j7.78
41.1 – j9.51
0.520
0.359
0.198
0.080
0.089
0.139
0.154
0.142
5
4
20
18
16
14
12
10
8
LOW SIDE LO
HIGH SIDE LO
IIP3
3
2
1
0
GAIN
151
–1
–2
–3
–4
–5
LOW SIDE LO
HIGH SIDE LO
140
6
127
4
2
0
+
RF
0
200 300 400 500 600 700
INPUT FREQUENCY (MHz)
100
11
5520 F06
Figure 6. Conversion Gain and IIP3
vs Tuned IF Input Frequency
V
CC
–
18
RF
RF
OUT
10
50Ω
LT5520
P
LO
= –5dBm
8
5520 F05
17
16
15
14
13
HIGH SIDE LO
V
CC
Figure 5. RF Output Circuit
Operation at Different Input Frequencies
P
LO
= 0dBm
LOW SIDE LO
On the evaluation board shown in Figure 10, the input of
theLT5520canbeeasilymatchedfordifferentfrequencies
by changing the input capacitors, C1 and C2. Table 4 lists
some actual values used at selected frequencies.
0
200 300 400 500 600 700
INPUT FREQUENCY (MHz)
100
5520 F07
Table 4. Input Capacitor Values vs Frequency
Frequency
(MHz)
Capacitance (C1, C2)
(pF)
Figure 7. SSB Noise Figure vs Tuned IF Input Frequency
70
820
220
68
140
240
480
650
18
12
5520f
8
LT5520
U
W
U U
APPLICATIO S I FOR ATIO
Figures 6-8 illustrate the performance versus tuned IF
input frequency with both high side and low side LO
injection. Figure 6 shows the measured conversion gain
and IIP3. The noise figure is plotted in Figure 7 for LO
power levels of –5dBm and 0dBm. At lower input frequen-
cies, the LO power level has little impact on noise figure.
However, for higher frequencies, an increased LO drive
level may be utilized to achieve better noise figure. The
single-tone IIP2 behavior is illustrated in Figure 8.
Low Frequency Matching of the RF Output Port
Without any external components on the RF output, the
internal transformer of the LT5520 provides a good 50Ω
impedancematchforRFfrequenciesaboveapproximately
1600MHz. At frequencies lower than this, the return loss
drops below 10dB and degrades the conversion gain. The
addition of a single 3.3pF capacitor in series with the RF
output improves the match at lower RF frequencies,
shifting the 10dB return loss point to about 1300MHz, as
demonstrated in Figure 9. This change also results in an
improvement of the conversion gain, as shown in
Figure 9.
60
1
0
0
C
= 3.3pF
OUT
LOW SIDE LO
50
–1
–2
–3
–4
–5
–6
–7
–8
–9
–5
NO C
OUT
GAIN
40
–10
–15
–20
–25
HIGH SIDE LO
30
20
10
0
RETURN LOSS
NO C
OUT
C
= 3.3pF
OUT
400
100 200 300
INPUT FREQUENCY (MHz)
600 700
0
500
1200 1400
1800 2000 2200 2400
FREQUENCY (MHz)
1600
5520 F08
5520 F09
Figure 8. IIP2 vs Tuned IF Input Frequency
Figure 9. Conversion Gain and Return Loss vs Output Frequency
5520f
9
LT5520
U
W
U U
APPLICATIO S I FOR ATIO
(10a) Top Layer Silkscreen
(10b) Top Layer Metal
Figure 10. Evaluation Board Layout
5520f
10
LT5520
U
PACKAGE DESCRIPTIO
UF Package
16-Lead Plastic QFN (4mm × 4mm)
(Reference LTC DWG # 05-08-1692)
BOTTOM VIEW—EXPOSED PAD
0.75 ± 0.05
R = 0.115
TYP
0.55 ± 0.20
4.00 ± 0.10
(4 SIDES)
15
16
0.72 ±0.05
PIN 1
TOP MARK
1
2
4.35 ± 0.05
2.90 ± 0.05
2.15 ± 0.05
(4 SIDES)
2.15 ± 0.10
(4-SIDES)
PACKAGE
OUTLINE
(UF) QFN 0802
0.30 ± 0.05
0.65 BSC
0.200 REF
0.30 ±0.05
0.65 BCS
0.00 – 0.05
NOTE:
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
1. DRAWING CONFORMS TO JEDEC PACKAGE OUTLINE MO-220 VARIATION (WGGC)
2. ALL DIMENSIONS ARE IN MILLIMETERS
3. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE
MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE
4. EXPOSED PAD SHALL BE SOLDER PLATED
5520f
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.
11
LT5520
RELATED PARTS
PART NUMBER
Infrastructure
LT5511
DESCRIPTION
COMMENTS
High Signal Level Upconverting Mixer
RF Output to 3GHz, 17dBm IIP3, Integrated LO Buffer
RF Input to 3GHz, 20dBm IIP3, Integrated LO Buffer
LT5512
DC-3GHz High Signal Level Downconverting Mixer
LT5515
1.5GHz to 2.5GHz Direct Conversion Quadrature Demodulator 20dBm IIP3,Integrated LO Quadrature Generator
0.8GHz to 1.5GHz Direct Conversion Quadrature Demodulator 21.5dBm IIP3,Integrated LO Quadrature Generator
LT5516
LT5522
600MHz to 2.7GHz High Signal Level Downconverting Mixer
4.5V to 5.25V Supply, 25dBm IIP3 at 900MHz, NF = 12.5dB,
50Ω Single-Ended RF and LO Ports
RF Power Detectors
LT5504
800MHz to 2.7GHz RF Measuring Receiver
RF Power Detectors with >40dB Dynamic Range
100kHz to 1000MHz RF Power Detector
300MHz to 7GHz RF Power Detector
80dB Dynamic Range, Temperature Compensated, 2.7V to 6V Supply
300MHz to 3GHz, Temperature Compensated, 2.7V to 5.5V Supply
300MHz to 3GHz, Temperature Compensated, 2.7V to 5.5V Supply
44dB Dynamic Range, Temperature Compensated, SC70 Package
36dB Dynamic Range, Temperature Compensated, SC70 Package
LTC5505
LTC5507
LTC5508
LTC5509
300MHz to 3GHz RF Power Detector
LTC5532
300MHz to 7GHz Precision RF Power Detector
Precision V
Offset Control, Adjustable Gain and Offset
OUT
RF Receiver Building Blocks
LT5500
LT5502
1.8GHz to 2.7GHz Receiver Front End
1.8V to 5.25V Supply, Dual-Gain LNA, Mixer LO Buffer
400MHz Quadrature IF Demodulator with RSSI
1.8V to 5.25V Supply, 70MHz to 400MHz IF, 84dB Limiting Gain,
90dB RSSI Range
LT5503
LT5506
LT5546
1.2GHz to 2.7GHz Direct IQ Modulator and
Upconverting Mixer
1.8V to 5.25V Supply, Four-Step RF Power Control,
120MHz Modulation Bandwidth
500MHz Quadrature IF Demodulator with VGA
1.8V to 5.25V Supply, 40MHz to 500MHz IF, –4dB to 57dB
Linear Power Gain, 8.8MHz Baseband Bandwidth
500MHz Ouadrature IF Demodulator with
VGA and 17MHz Baseband Bandwidth
1.8V to 5.25V Supply, 40MHz to 500MHz IF,
–7dB to 56dB Linear Power Gain
5520f
LT/TP 1103 1K • PRINTED IN USA
12 LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
●
●
LINEAR TECHNOLOGY CORPORATION 2003
(408) 432-1900 FAX: (408) 434-0507 www.linear.com
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