LT5520
1.3GHz to 2.3GHz
High Linearity
Upconverting Mixer
FEATURES
s
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DESCRIPTIO
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 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,
while reducing system cost, component count, board area
and system-level variations. The IF port can be easily
matched to a broad range of frequencies for use in many
different applications.
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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIO S
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Wireless Infrastructure
Cable Downlink Infrastructure
Point-to-Point Data Communications
High Linearity Frequency Conversion
TYPICAL APPLICATIO
5V
DC
1µF
1000pF
39nH
EN
BPF
IF
INPUT
4:1
IF
+
15pF
IF
–
220pF
100Ω
RF
–
BPF
PA
RF
OUTPUT
RF
+
100Ω
BIAS
V
CC1
V
CC2
V
CC3
P
OUT
, IM3 (dBm/TONE)
220pF
10pF
GND
5pF
(OPTIONAL)
LO INPUT
–5dBm
LO
+
85Ω
5pF
LO
–
LT5520
5520 F01
Figure 1. Frequency Conversion in Wireless Infrastructure Transmitter
5520f
U
RF Output Power and Output IM3 vs
IF Input Power (Two Input Tones)
10
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–16
IM3
P
LO
= –5dBm
f
LO
= 1760MHz
f
IF1
= 140MHz
f
IF2
= 141MHz
f
RF
= 1900MHz
T
A
= 25°C
4
5520 • F01b
U
U
P
OUT
–12
–4
0
–8
IF INPUT POWER (dBm/TONE)
1
LT5520
ABSOLUTE
(Note 1)
AXI U RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
Supply Voltage ....................................................... 5.5V
Enable Voltage ............................. –0.3V to (V
CC
+ 0.3V)
LO Input Power (Differential) .............................. 10dBm
RF
+
to RF
–
Differential DC Voltage......................
±0.13V
RF Output DC Common Mode Voltage ......... –1V to V
CC
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 V
CC
Operating Temperature Range .................–40°C to 85°C
Storage Temperature Range ................. – 65°C to 125°C
Junction Temperature (T
J
).................................... 125°C
ORDER PART
NUMBER
12 GND
11 RF
+
10 RF
–
9 GND
GND
16 15 14 13
GND 1
IF
+
2
IF
–
3
GND 4
5
6
7
8
17
GND
LO
–
LO
+
LT5520EUF
UF PACKAGE
16-LEAD (4mm
×
4mm) PLASTIC QFN
EXPOSED PAD IS GND (PIN 17),
MUST BE SOLDERED TO PCB
UF PART
MARKING
5520
V
CC1
V
CC2
T
JMAX
= 125°C,
θ
JA
= 37°C/W
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
PARAMETER
IF Input Frequency Range
LO Input Frequency Range
RF Output Frequency Range
CONDITIONS
MIN
TYP
DC to 400
900 to 2700
1300 to 2300
MAX
UNITS
MHz
MHz
MHz
1900MHz Application: V
CC
= 5V
DC
, EN = High, T
A
= 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
IF Input Return Loss
LO Input Return Loss
RF Output Return Loss
LO Input Power
Conversion Gain
Input 3rd Order Intercept
Input 2nd Order Intercept
LO to RF Leakage
LO to IF Leakage
Input 1dB Compression
IF Common Mode Voltage
Noise Figure
Internally Biased
Single Side Band
–10dBm/Tone,
∆f
= 1MHz
–10dBm, Single-Tone
CONDITIONS
Z
O
= 50Ω, with External Matching
Z
O
= 50Ω
Z
O
= 50Ω
MIN
TYP
20
16
20
–10 to 0
–1
15.9
45
–41
–35
4
1.77
15
MAX
UNITS
dB
dB
dB
dBm
dB
dBm
dBm
dBm
dBm
dBm
V
DC
dB
DC ELECTRICAL CHARACTERISTICS
(Test Circuit Shown in Figure 2) V
CC
= 5V
DC
, EN = High , T
A
= 25°C (Note 3), unless otherwise noted.
PARAMETER
Enable (EN) Low = Off, High = On
Turn-On Time (Note 4)
Turn-Off Time (Note 4)
Input Current
V
ENABLE
= 5V
DC
2
6
1
10
µs
µs
µA
5520f
CONDITIONS
V
CC3
EN
MIN
TYP
MAX
UNITS
2
U
W
U
U
W W
W
LT5520
DC ELECTRICAL CHARACTERISTICS
(Test Circuit Shown in Figure 2) V
CC
= 5V
DC
, EN = High , T
A
= 25°C (Note 3), unless otherwise noted.
PARAMETER
Enable = High (On)
Enable = Low (Off)
Power Supply Requirements (V
CC
)
Supply Voltage
Supply Current
Shutdown Current
V
CC
= 5V
DC
EN = Low
4.5 to 5.25
60
1
70
100
V
DC
mA
µA
CONDITIONS
MIN
3
0.5
TYP
MAX
UNITS
V
DC
V
DC
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
External components on the final test circuit are optimized for
operation at f
RF
= 1900MHz, f
LO
= 1.76GHz and f
IF
= 140MHz.
Note 3:
Specifications over the –40°C to 85°C temperature range are
assured by design, characterization and correlation with statistical process
controls.
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.
TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current
vs Supply Voltage
66
64
SUPPLY CURRENT (mA)
62
60
58
56
54
52
50
4.0
4.25
4.5
4.75
5.0
SUPPLY VOLTAGE (V)
5.25
5.5
T
A
= –40°C
T
A
= 25°C
SHUTDOWN CURRENT (µA)
T
A
= 85°C
V
CC
= 5V
DC
, EN = High, T
A
= 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
18
16 HIGH SIDE LO
14
12
GAIN, NF (dB)
LOW SIDE LO
SSB NF
IIP3 (dBm)
10
8
6
4
2
0
–2
–4
1300
1500 1700 1900 2100 2300 2500
RF OUTPUT FREQUENCY (MHz)
5520 • GO3
24
22
20
18
IIP3
LOW SIDE LO
HIGH SIDE LO
HIGH SIDE LO
35
30
25
20
15
10
5
2500
LO LEAKAGE (dBm)
GAIN
LOW SIDE AND HIGH SIDE LO
U W
(Test Circuit Shown in Figure 2)
Shutdown Current
vs Supply Voltage
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
4.0
4.25
T
A
= 25°C
T
A
= –40°C
5.25
4.5
4.75
5.0
SUPPLY VOLTAGE (V)
5.5
T
A
= 85°C
5520 • GO1
5520 • GO2
32
30
28
26
IIP3 and IIP2
vs RF Output Frequency
LOW SIDE LO
IIP2
55
50
45
40
IIP2 (dBm)
LO-RF Leakage
vs RF Output Frequency
–10
–20
–30
HIGH SIDE LO
–40
16
14
–50
LOW SIDE LO
12
1300
1500 1700 1900 2100 2300
RF OUTPUT FREQUENCY (MHz)
–60
1300
1500 1700 1900 2100 2300
RF OUTPUT FREQUENCY (MHz)
2500
5520 • GO4
5520 • GO5
5520f
3
LT5520
TYPICAL PERFOR A CE CHARACTERISTICS
V
CC
= 5V
DC
, EN = High , T
A
= 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
16
14
12
10
GAIN (dB)
8
6
4
2
0
–2
–4
–16
T
A
= 85°C
–12
–8
–4
0
LO INPUT POWER (dBm)
4
5520 • G06
T
A
= 85°C
T
A
= 25°C
T
A
= –40°C
12
10
8
IIP3, IIP2 (dBm)
IIP2
30
25
20
15
10
5
0
–16
0
–8
–12
–4
LO INPUT POWER (dBm)
4
5520 • G07
LO LEAKAGE (dBm)
GAIN
T
A
= –40°C
T
A
= 25°C
IIP3 and IIP2 vs
LO Input Power
50
LOW SIDE LO
45
40
IIP3, IIP2 (dBm)
35
30
25
20
15
10
5
0
–16
0
–8
–12
–4
LO INPUT POWER (dBm)
4
5520 • G09
P
OUT
, IM3 (dBm/TONE)
P
OUT
, IM2 (dBm/TONE)
IIP2
HIGH SIDE LO
IIP3
HIGH SIDE LO
LOW SIDE LO
Conversion Gain vs IF Input
Power (One Input Tone)
4
3
2
RETURN LOSS (dB)
1
GAIN (dB)
0
–1
–2
–3
–4
–5
–6
–16
–25
–12
0
–8
–4
IF INPUT POWER (dBm)
4
5520 • G12
T
A
= –40°C
T
A
= 25°C
T
A
= 85°C
GAIN (dB)
4
U W
SSB NF
IIP3 and IIP2 vs
LO Input Power
20
18
16
14
NF (dB)
50
45
40
35
T
A
= –40°C
T
A
= 25°C
T
A
= 85°C
–20
–10
LO-RF Leakage
vs LO Input Power
–30
T
A
= –40°C
–40
T
A
= 25°C
–50
T
A
= 85°C
IIP3
T
A
= 25°C, T
A
= –40°C
T
A
= 85°C
6
4
2
0
–60
–16
0
–8
–12
–4
LO INPUT POWER (dBm)
4
5520 • G08
RF Output Power and Output IM3 vs
IF Input Power (Two Input Tones)
10
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–16
0
–8
–12
–4
IF INPUT POWER (dBm/TONE)
4
5520 • G10
RF Output Power and Output IM2 vs
IF Input Power (Two Input Tones)
10
0
T
A
= –40°C
T
A
= 85°C
P
OUT
T
A
= 25°C
–10
–20
–30
–40
–50
T
A
= –40°C
T
A
= 85°C
P
OUT
T
A
= –40°C
T
A
= 25°C
T
A
= –40°C
IM3
T
A
= 85°C
IM2
–60
–70
–80
–16
T
A
= 85°C
T
A
= 25°C
0
–8
–12
–4
IF INPUT POWER (dBm/TONE)
4
5520 • G11
IF, LO and RF Port Return Loss
vs Frequency
0
8
7
–5
6
5
–10
4
3
2
1
0
IF PORT
0
500
RF PORT
1000 1500 2000
FREQUENCY (MHz)
2500
3000
–1
Conversion Gain, IIP3 and IIP2
vs Supply Voltage
50
LOW SIDE LO
HIGH SIDE LO
45
40
IIP2
35
30
25
IIP3
HIGH SIDE LO
LOW SIDE LO
GAIN
LOW SIDE AND HIGH SIDE LO
4.25
5.25
4.5
4.75
5.0
SUPPLY VOLTAGE (V)
20
15
10
5
0
5.5
IIP3, IIP2 (dBm)
–15
LO PORT
–20
–2
4.0
5520 • G13
5520 • G14
5520f
LT5520
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
blocking capacitors. The pins must be connected to ground
with 100Ω resistors (the grounds must each be capable of
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).
EN (Pin 5):
Enable Pin. When the applied voltage is greater
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.
V
CC1
(Pin 6):
Power Supply Pin for the Bias Circuits.
Typical current consumption is about 2mA. This pin
should be externally connected to V
CC
and have appropri-
ate RF bypass capacitors.
V
CC2
(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
in Figure 2. The 1000pF capacitor should be located as
close to the pins as possible.
V
CC3
(Pin 8):
Power Supply Pin for the Internal Mixer.
Typical current consumption is about 36mA. This pin
should be externally connected to V
CC
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
may be DC connected to a low impedance ground to realize
a 50Ω single-ended output. No external matching compo-
nents are required. A DC voltage should not be applied
across these pins, as they are internally connected through
a transformer winding.
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
impedance ground. No external matching components are
required. An internal resistor is connected across these
pins; therefore, a DC voltage should not be applied across
the inputs.
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.
BLOCK DIAGRA
W
U
U
U
BACKSIDE
GROUND GND
17
12
GND
13
5pF
LO
+
14
85Ω
LO
–
15
5pF
GND
16
HIGH SPEED
LO BUFFER
RF
+
11
RF
–
10
GND
9
8 V
CC3
10pF
DOUBLE-
BALANCED
MIXER
6 V
CC1
BIAS
5 EN
7
V
CC2
1
GND
2
IF
+
3
IF
–
4
GND
5520 BD
5520f
5
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