LTC5551 - 300MHz to 3.5GHz Ultra-High Dynamic Range Downconverting Mixer

LTC5551
300MHz to 3.5GHz
Ultra-High Dynamic Range
Downconverting Mixer
Description
Features
+36dBm Input IP3
n 2.4dB Conversion Gain
n Low Noise Figure: <10dB
n+18dBm Ultra High Input P1dB
n 670mW Power Consumption
n 2.5V to 3.6V Operation
n 50Ω Single-Ended RF and LO Inputs
n0dBm LO Drive Level
n Low Power Mode
n–40°C to 105°C Operation (T )
C
n Small Solution Size
n Enable Pin
n16-Lead (4mm × 4mm) QFN Package
The LTC®5551 is a 2.5V to 3.6V mixer optimized for RF
downconverting mixer applications that require very high
dynamic range. The LTC5551 covers the 300MHz to
3.5GHz RF Frequency range with LO frequency range
of 200MHz to 3.5GHz. The LTC5551 provides very high
IIP3 and P1dB with low power consumption. A typical
application is a basestation receiver covering 700MHz to
2.7GHz frequency range. The RF input can be matched for a
wide range of frequencies and the IF is usable up to 1GHz.
n
A low power mode is activated by pulling the ISEL pin high,
reducing the power consumption by about 1/3, however,
with a corresponding reduction in IIP3 to approximately
+29dBm. The mixer can also be turned on or off by using
the EN pin.
Applications
n
n
n
n
n
n
n
The LTC5551’s high level of integration minimizes the
total solution cost, board space and system level variation,
while providing the highest dynamic range for demanding
receiver applications.
GSM, LTE, LTE-Advanced Basestations
Repeaters
DPD Observation Receiver
Public Safety Radios, Military and Defense
Avionics Radios and TCAS Transponders
Active Phased-Array Antennas
White-Space Radio Receiver
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 8558605.
Typical Application
Wideband Receiver
1nF
VCC
3.3V
0.56µF
22pF
BPF
470nH
470nH
475Ω
475Ω
LTC6416
IF
AMP
Mixer Conversion Gain and IIP3
vs IF Frequency (Low-Side LO)
LTC2208
39
ADC
6
36
33
1nF
IIP3
5
RF = 1770MHz TO 1970MHz
LO = 1700MHz
ZIF = 200Ω
4
2.2pF
RFIN
IF –
IF
LTC5551
RF
LO
LO
7.5nH
EN
(0V/3.3V)
VCC
3.3V
3.9pF
LTC6946
SYNTH
LO
1700MHz
24
21
18
VCC
3
GC
15
12
9
BIAS
EN
27
GC (dB)
IF+
IIP3 (dBm)
30
2
NORMAL POWER MODE
LOW POWER MODE
1
70 90 110 130 150 170 190 210 230 250 270
IF FREQUENCY (MHz)
5551 TA01b
5551 TA01a
0.56µF
22pF
5551fa
For more information www.linear.com/LTC5551
1
LTC5551
Absolute Maximum Ratings
Pin Configuration
(Note 1)
Supply Voltage (VCC, IF+, IF –)......................................4V
Enable Input Voltage (EN).................–0.3V to VCC + 0.3V
Power Select Voltage (ISEL).............–0.3V to VCC + 0.3V
LO Input Power (0.2GHz to 3.5GHz).................... +10dBm
LO Input DC Voltage ............................................. ±0.1V
RF Input Power (0.3GHz to 3.5GHz)....................+20dBm
RF Input DC Voltage................................................ ±0.1V
TEMP Diode Continuous DC Input Current..............10mA
TEMP Diode Input Voltage......................................... ±1V
IFBIAS Voltage..........................................................2.5V
Operating Temperature Range (TC)......... –40°C to 105°C
Storage Temperature Range................... –65°C to 150°C
Junction Temperature (TJ)..................................... 150°C
GND
IF–
IF+
IFBIAS
TOP VIEW
16 15 14 13
TP 1
12 TEMP
RF 2
11 GND
17
GND
CT 3
10 LO
GND 4
6
7
8
EN
VCC
VCC
ISEL
9
5
GND
UF PACKAGE
16-LEAD (4mm × 4mm) PLASTIC QFN
TJMAX = 150°C, θJC = 6°C/W
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
CAUTION: This part is sensitive to electrostatic discharge
(ESD). It is very important that proper ESD precautions
be observed when handling the LTC5551.
Order Information
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
CASE TEMPERATURE RANGE
LTC5551IUF#PBF
LTC5551IUF#TRPBF
5551
16-Lead (4mm × 4mm) Plastic QFN
–40°C to 105°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
2
5551fa
For more information www.linear.com/LTC5551
LTC5551
AC Electrical Characteristics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TC = 25°C. VCC = 3.3V, EN = High, ISEL = Low, PLO = 0dBm, unless otherwise
noted. Test circuit shown in Figure 1. (Notes 2, 3)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
LO Input Frequency Range
l
200 to 3500
MHz
RF Input Frequency Range
l
300 to 3500
MHz
5 to 1000
MHz
IF Output Frequency Range
Requires External Matching
RF Input Return Loss
ZO = 50Ω, 1100MHz to 2700MHz, X1 = 7.5nH, C1 = 2.2pF
LO Input Return Loss
ZO = 50Ω, 1000MHz to 3500MHz, C2 = 3.9pF
IF Output Impedance
Differential at 153MHz
LO Input Power
LO = 200MHz to 3500MHz
LO to RF Leakage
LO = 200MHz to 3500MHz
< –25
dBm
LO to IF Leakage
LO = 200MHz to 3500MHz
< –21
dBm
RF to LO Isolation
RF = 300MHz to 3500MHz
>55
dB
RF to IF Isolation
RF = 300MHz to 3500MHz
>23
dB
>12
dB
>12
950Ω || 1.2pF
dB
R||C
–6
0
6
dBm
The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TC = 25°C.
VCC = 3.3V, EN = High, PLO = 0dBm, PRF = 0dBm (0dBm/tone for 2-tone tests), unless otherwise noted. Test circuit shown in Figure 1.
(Notes 2, 3)
0.3GHz to 3.5GHz Downmixer Application: IF = 153MHz, ISEL = Low, unless otherwise noted. (Notes 2, 3)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Power Conversion Gain
RF = 400MHz, High Side LO
RF = 850MHz, High Side LO
RF = 1950MHz, Low Side LO
RF = 2700MHz, Low Side LO
3.2
2.8
2.4
1.7
dB
dB
dB
dB
Conversion Gain Flatness
RF = 1870MHz ±100MHz, LO = 1700MHz, IF = 170 ±100MHz
±0.2
dB
Conversion Gain vs Temperature
TC = –40°C to 105°C, RF = 1950MHz, Low Side LO
–0.013
dB/°C
2-Tone Input 3rd Order Intercept
(∆f = 2MHz)
RF = 400MHz, High Side LO
RF = 850MHz, High Side LO
RF = 1950MHz, Low Side LO
RF = 2700MHz, Low Side LO
33.2
35.2
35.5
38.1
dBm
dBm
dBm
dBm
2-Tone Input 2nd Order Intercept
(∆f = 154MHz = fIM2)
RF = 400MHz (477MHz/323MHz), LO = 553MHz
RF = 850MHz (927MHz/773MHz), LO = 1053MHz
RF = 1950MHz (2027MHz/1873MHz), LO = 1797MHz
RF = 2700MHz (2777MHz/2623MHz), LO = 2547MHz
65.8
68.2
58.4
57.1
dBm
dBm
dBm
dBm
SSB Noise Figure
RF = 400MHz, High Side LO
RF = 850MHz, High Side LO
RF = 1950MHz, Low Side LO
RF = 2700MHz, Low Side LO
10.6
9.1
9.7
10.9
dB
dB
dB
dB
SSB Noise Figure Under Blocking
RF = 850MHz, High Side LO, 750MHz Blocker at 5dBm
RF = 1950MHz, Low Side LO, 2050MHz Blocker at 5dBm
16.5
16.9
dB
dB
1/2 IF Output Spurious Product
(fRF Offset to Produce Spur at fIF = 153MHz)
850MHz: RF = 926.5MHz at –3dBm, LO = 1003MHz
1950MHz: RF = 1873.5MHz at –3dBm, LO = 1797MHz
–66
–68
dBc
dBc
1/3 IF Output Spurious Product
(fRF Offset to Produce Spur at fIF = 153MHz)
850MHz: RF = 952MHz at –3dBm, LO = 1003MHz
1950MHz: RF = 1848MHz at –3dBm, LO = 1797MHz
–97
–93
dBc
dBc
Input 1dB Compression
RF = 400MHz, High Side LO
RF = 850MHz, High Side LO
RF = 1950MHz, Low Side LO
RF = 2700MHz, Low Side LO
17.1
17.8
18.0
18.7
dBm
dBm
dBm
dBm
5551fa
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3
LTC5551
AC Electrical Characteristics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. VCC = 3.3V, EN = High, PLO = 0dBm, PRF = 0dBm (0dBm/tone for 2-tone
tests), unless otherwise noted. Test circuit shown in Figure 1. (Notes 2, 3)
Low Power Mode, 0.3GHz to 3.5GHz Downmixer Application: IF = 153MHz, ISEL = High (Notes 2, 3)
PARAMETER
CONDITIONS
Power Conversion Gain
RF = 400MHz, High Side LO
RF = 850MHz, High Side LO
RF = 1950MHz, Low Side LO
RF = 2700MHz, Low Side LO
MIN
TYP
3.0
2.7
2.4
1.7
MAX
UNITS
dB
dB
dB
dB
Input 3rd Order Intercept
RF = 400MHz, High Side LO
RF = 850MHz, High Side LO
RF = 1950MHz, Low Side LO
RF = 2700MHz, Low Side LO
27.3
28.0
29.3
29.7
dBm
dBm
dBm
dBm
SSB Noise Figure
RF = 400MHz, High Side LO
RF = 850MHz, High Side LO
RF = 1950MHz, Low Side LO
RF = 2700MHz, Low Side LO
9.8
8.2
8.3
9.2
dB
dB
dB
dB
Input 1dB Compression
RF = 400MHz, High Side LO
RF = 850MHz, High Side LO
RF = 1950MHz, Low Side LO
RF = 2700MHz, Low Side LO
14.8
16.2
16.7
17.7
dBm
dBm
dBm
dBm
DC Electrical Characteristics
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TC = 25°C. VCC = 3.3V, EN = High, ISEL = Low, unless otherwise noted. Test circuit
shown in Figure 1. (Note 2)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
2.5
3.3
3.6
VDC
234
100
mA
mA
µA
100
mA
mA
µA
Power Supply Requirements
Supply Voltage (VCC)
l
Supply Current (ISEL = Low)
EN = High, No LO Applied
EN = High, with LO Applied
EN = Low
148
204
Supply Current – Low Power Mode (ISEL = High)
EN = High, No LO Applied
EN = High, with LO Applied
EN = Low
128
142
Enable Logic Input (EN)
Input High Voltage (On)
l
Input Low Voltage (Off)
l
1.2
VDC
–30
0.3
VDC
100
µA
Input Current
–0.3V to VCC + 0.3V
Turn On Time
LO Applied
0.4
µs
Turn Off Time
LO Applied
0.5
µs
Power Select Logic Input (ISEL)
Input High Voltage (Low Power Mode)
l
Input Low Voltage (High Power Mode)
Input Current
1.2
VDC
l
–0.3V to VCC + 0.3V
–30
0.3
VDC
100
µA
Temperature Sensing Diode (TEMP)
DC Voltage at TJ = 25°C
IIN = 10µA
IIN = 80µA
Voltage Temperature Coefficient
IIN = 10µA
IIN = 80µA
4
726
783
l
l
–1.72
–1.53
mV
mV
mV/°C
mV/°C
5551fa
For more information www.linear.com/LTC5551
LTC5551
Electrical Characteristics
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LTC5551 is guaranteed functional over the –40°C to 105°C
case temperature range.
Note 3: SSB Noise Figure measurements performed with a small-signal
noise source, bandpass filter and 6dB matching pad on RF input, bandpass
filter and 6dB matching pad on the LO input, bandpass filter on the IF
output and no other RF signals applied.
Typical DC Performance Characteristics
Supply Current vs Supply Voltage,
LO = 1800MHz at 0dBm
Supply Current vs Supply Voltage,
No LO Applied
180
250
ISEL = LOW
200
ICC (mA)
ICC (mA)
ISEL = HIGH
100
80
60
50
VCC = 3.5V
VCC = 3.3V
VCC = 3.1V
35
10
60
85
CASE TEMPERATURE (°C)
110
40
VCC = 3.5V
VCC = 3.3V
VCC = 3.1V
20
0
–40
–15
35
10
60
85
CASE TEMPERATURE (°C)
Supply Current vs VCC
LO = 1800MHz at 0dBm
ISEL = HIGH
100
TC = 105°C
TC = 85°C
TC = 25°C
TC = –40°C
50
0
300 700 1100 1500 1900 2300 2700 3100 3500
LO FREQUENCY (MHz)
5551 G03
Supply Current vs VCC
LO = 1800MHz at TC = 25°C
220
220
190
190
160
130
110
150
5551 G02
5551 G01
ICC (mA)
–15
ISEL = LOW
120
ISEL = HIGH
ICC (mA)
ICC (mA)
250
140
100
0
–40
Supply Current vs LO Frequency
(PLO = 0dBm)
ISEL = LOW
160
200
150
EN = High, Test circuit shown in Figure 1.
TC = 105°C
TC = 85°C
TC = 25°C
TC = –40°C
100
2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6
VCC (V)
160
130
LO = 6dBm
LO = 0dBm
LO = –6dBm
100
2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6
VCC (V)
5551 G04
5551 G05
5551fa
For more information www.linear.com/LTC5551
5
LTC5551
Typical AC Performance Characteristics
1100MHz to 2700MHz application.
VCC = 3.3V, EN = High, ISEL = Low, TC = 25°C, PLO = 0dBm, PRF = 0dBm (0dBm/tone for two-tone IIP3 tests, ∆f = 2MHz), IF = 153MHz,
unless otherwise noted. Test circuit shown in Figure 1.
40
36
TC = 85°C
TC = 25°C
TC = –40°C
NF
GC
1.3
IIP3
32
IIP3
28
2.5
16
NF
12
8
GC
–6
–4
–2
0
2
4
LO INPUT POWER (dBm)
18
15
NF
12
9
6
IIP3 (dBm), NF (dB), GC (dB)
21
GC
3
0
1.1
1.3
2.5
GC
–4
–2
0
2
4
LO INPUT POWER (dBm)
32
28
TC = 85°C
TC = 25°C
TC = –40°C
24
20
16
NF
12
8
GC
0
2.7
–6
–4
IIP3
28
24
16
NF
12
8
GC
0
6
TC = 85°C
TC = 25°C
TC = –40°C
20
4
–2
0
2
4
LO INPUT POWER (dBm)
5551 G09
–6
–4
–2
0
2
4
LO INPUT POWER (dBm)
RF Isolation vs Frequency
20
6
5551 G11
5551 G10
Input P1dB vs RF Frequency
(Low Side LO)
6
2550MHz Conversion Gain, IIP3
and NF vs LO Power (High Side LO)
IIP3
4
1.5 1.7 1.9 2.1 2.3
RF FREQUENCY (GHz)
8
36
32
TC = 85°C
TC = 25°C
TC = –40°C
NF
12
5551 G08
IIP3 (dBm), NF (dB), GC (dB)
IIP3
24
16
–6
36
27
20
1950MHz Conversion Gain, IIP3
and NF vs LO Power (High Side LO)
36
30
24
0
6
TC = 85°C
TC = 25°C
TC = –40°C
28
5551 G07
Conversion Gain, IIP3 and NF
vs RF Frequency (High Side LO)
33
IIP3
32
4
5551 G06
IIP3 (dBm), NF (dB), GC (dB)
36
20
0
2.7
TC = 85°C
TC = 25°C
TC = –40°C
24
4
1.5 1.7 1.9 2.1 2.3
RF FREQUENCY (GHz)
2550MHz Conversion Gain, IIP3
and NF vs LO Power (Low Side LO)
IIP3 (dBm), NF (dB), GC (dB)
39
36
33
30
27
24
21
18
15
12
9
6
3
0
1.1
1950MHz Conversion Gain, IIP3
and NF vs LO Power (Low Side LO)
IIP3 (dBm), NF (dB), GC (dB)
IIP3 (dBm), NF (dB), GC (dB)
Conversion Gain, IIP3 and NF
vs RF Frequency (Low Side LO)
LO Leakage vs LO Frequency
0
70
19
60
15
14
13
TC = 105°C
TC = 85°C
TC = 25°C
TC = –40°C
11
10
1.1
1.3
1.5 1.7 1.9 2.1 2.3
RF FREQUENCY (GHz)
2.5
2.7
5551 G12
LO LEAKAGE (dBm)
16
12
6
–10
RF-LO
17
ISOLATION (dB)
INPUT P1dB (dBm)
18
50
40
30
1.3
1.5 1.7 1.9 2.1 2.3
RF FREQUENCY (GHz)
–30
LO-RF
–40
–50
RF-IF
20
1.1
LO-IF
–20
2.5
2.7
5551 G13
–60
1.1
1.3
1.5 1.7 1.9 2.1 2.3
LO FREQUENCY (GHz)
2.5
2.7
5551 G14
5551fa
For more information www.linear.com/LTC5551
LTC5551
Typical AC Performance Characteristics
1100MHz to 2700MHz application.
VCC = 3.3V, EN = High, ISEL = Low, TC = 25°C, PLO = 0dBm, PRF = 0dBm (0dBm/tone for two-tone IIP3 tests, ∆f = 2MHz), IF = 153MHz,
unless otherwise noted. Test circuit shown in Figure 1.
Single-Tone IF Output Power, 2 × 2
and 3 × 3 Spurs vs RF Input Power
20
20
0
–10
–20
RF1 = 1949MHz
RF2 = 1951MHz
LO = 1797MHz
–40
–50
–60
–70
IM3
–80
–100
–10 –7
–30
–40
2RF-2LO
RF = 1873.5MHz
–50
–60
–70
IM5
–90
–20
3RF-3LO
RF = 1848MHz
–80
–4 –1 2
5
8 11 14
RF INPUT POWER (dBm/TONE)
–90
17
–9
–6
–3 0
3
6
9 12 15
RF INPUT POWER (dBm/TONE)
5551 G15
SSB NF (dB)
14
12
8
–25
PLO = –6dBm
PLO = 0dBm
PLO = 6dBm
–20
–15 –10 –5
0
5
RF BLOCKER POWER (dBm)
RF = 1950MHz
LOW SIDE LO
HIGH SIDE LO
24
21
18
15
NF
12
9
6
GC
3
–4
10
5
32
4
RF = 1950MHz
LOW SIDE LO
HIGH SIDE LO 3
29
26
23
GC
20
40
40
30
20
10
0
1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4
CONVERSION GAIN (dB)
5551 G21
35
30
2
P1dB
17
14
1
NF
0
8
2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6
VCC SUPPLY VOLTAGE (V)
5551 G19
RF = 1950MHz
6
IIP3
5551 G20
1950MHz IIP3 Histogram
85°C
25°C
–40°C
–2
0
2
4
LO INPUT POWER (dBm)
5551 G17
11
0
–40 –25 –10 5 20 35 50 65 80 95 110
CASE TEMPERATURE (°C)
DISTRIBUTION (%)
DISTRIBUTION (%)
50
–6
35
27
1950MHz Conversion Gain
Histogram
60
3RF-3LO
RF = 1848MHz
–90
Conversion Gain, IIP3, P1dB and
SSB NF vs Supply Voltage
IIP3
30
5551 G18
70
–80
GC (dB)
16
2RF-2LO
RF = 1873.5MHz
38
33
18
10
–70
–100
36
IIP3 (dBm), NF (dB), GC (dB)
20
–60
Conversion Gain, IIP3 and SSB
NF vs Temperature
RF = 1950MHz
LO = 1797MHz
BLOCKER = 2050MHz
RF = 1950MHz
PRF = –3dBm
LO = 1797MHz
5551 G16
SSB Noise Figure
vs RF Blocker Level
22
18
IIP3 (dBm), P1dB (dBm), NF (dB)
–30
LO = 1797MHz
–10
1950MHz SSB NF Histogram
40
RF = 1950MHz
85°C
25°C
–40°C
RF = 1950MHz
35
85°C
25°C
–40°C
30
DISTRIBUTION (%)
0
–50
IFOUT
RF = 1950MHz
10
IFOUT
OUTPUT POWER (dBm)
OUTPUT POWER/TONE (dBm)
10
2 × 2 and 3 × 3 Spurs
vs LO Power
RELATIVE SPUR LEVEL (dBc)
2-Tone IF Output Power, IM3 and
IM5 vs RF Input Power
25
20
15
25
20
15
10
10
5
5
0
33.2 33.6 34 34.4 34.8 35.2 35.8 36 36.4
IIP3 (dBm)
0
8.8
5551 G22
9.2
10.4 10.8
9.6
10
SSB NOISE FIGURE (dB)
11.2
5551 G23
5551fa
For more information www.linear.com/LTC5551
7
LTC5551
Typical AC Performance Characteristics
1100MHz to 2700MHz application. Low
Power Mode. VCC = 3.3V, EN = High, ISEL = High, TC = 25°C, PLO = 0dBm, PRF = 0dBm (0dBm/tone for two-tone IIP3 tests, ∆f = 2MHz),
IF = 153MHz, unless otherwise noted. Test circuit shown in Figure 1.
Conversion Gain, IIP3 and NF
vs RF Frequency (High Side LO)
31
28
28
LOW POWER MODE
85°C
25°C
–40°C
19
16
13
NF
10
7
GC
4
1.3
19
16
13
NF
10
2.5
GC
1
1.1
2.7
19
35
1.3
1.5 1.7 1.9 2.1 2.3
RF FREQUENCY (GHz)
INPUT P1dB (dBm)
14
13
LOW POWER MODE
LOW SIDE LO
HIGH SIDE LO
1.3
1.5 1.7 1.9 2.1 2.3
RF FREQUENCY (GHz)
2.5
2.7
IIP3
29
3
GC
23
20
2
17
–30
–40
–50
–60
–70
IM3
10
LO-RF
–40
1.1
1.3
1.5 1.7 1.9 2.1 2.3
LO/RF FREQUENCY (GHz)
2.5
LOW POWER MODE
LO = 1797MHz
–10
–20
–30
–40
–50
2RF-2LO
RF = 1873.5MHz
–90
–10 –8 –6 –4 –2 0 2 4 6 8 10 12 14 16
RF INPUT POWER (dBm/TONE)
–80
–10 –7
–10
2.7
5551 G29
2 × 2 and 3 × 3 Spurs
vs LO Power
–50
–70
8
LO-IF
IFOUT
RF = 1950MHz
–80
5551 G30
30
–30
Single Tone IF Output Power, 2 × 2
and 3 × 3 Spurs vs RF Input Power
0
50
RF-IF
–20
NF
–60
IM5
LOW POWER MODE
5551 G28
LOW POWER MODE
RF1 = 1949MHz
RF2 = 1951MHz
LO = 1797MHz
70
–10
0
8
2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6
VCC SUPPLY VOLTAGE (V)
10
0
RF-LO
1
11
6
0
P1dB
14
OUTPUT POWER (dBm)
OUTPUT POWER/TONE (dBm)
–20
2
4
–2
0
LO INPUT POWER (dBm)
5551 G26
20
IFOUT
–4
LO Leakage and RF Isolation
26
20
0
–6
LOW POWER MODE
RF = 1950MHz
LOW SIDE LO 4
HIGH SIDE LO
32
2-Tone IF Output Power, IM3 and
IM5 vs RF Input Power
–10
7
2.7
5
5551 G27
10
NF
RF ISOLATION (dB)
15
11
2.5
GC (dB)
16
IIP3 (dBm), P1dB (dBm), NF (dB)
38
17
2
LOW POWER MODE
RF = 1950MHz
LOW SIDE LO
HIGH SIDE LO 1
16
Conversion Gain, IIP3, P1dB and
NF vs Supply Voltage
20
10
1.1
19
5551 G25
Input P1dB vs RF Frequency
12
22
10
5551 G24
18
3
GC
13
7
4
1.5 1.7 1.9 2.1 2.3
RF FREQUENCY (GHz)
IIP3
25
LOW POWER MODE
85°C
25°C
–40°C
22
4
28
RELATIVE SPUR LEVEL (dBc)
1
1.1
IIP3
25
LO LEAKAGE (dBm)
22
IIP3 (dBm), NF (dB), GC (dB)
IIP3
25
31
NF (dB), IIP3 (dBm)
31
1950MHz Conversion Gain, IIP3
and NF vs LO Power
GC (dB)
IIP3 (dBm), NF (dB), GC (dB)
Conversion Gain, IIP3 and NF
vs RF Frequency (Low Side LO)
–60
2RF-2LO
RF = 1873.5MHz
LOW POWER MODE
RF = 1950MHz
PRF = –3dBm
LO = 1797MHz
–70
–80
3RF-3LO
RF = 1848MHz
–90
3RF-3LO
RF = 1848MHz
–4 –1 2
5
8 11 14
RF INPUT POWER (dBm/TONE)
17
5551 G31
–100
–6
–4
–2
0
2
4
LO INPUT POWER (dBm)
6
5551 G32
5551fa
For more information www.linear.com/LTC5551
LTC5551
Typical AC Performance Characteristics
300MHz to 650MHz application.
VCC = 3.3V, EN = High, ISEL = Low, TC = 25°C, PLO = 0dBm, PRF = 0dBm (0dBm/tone for two-tone IIP3 tests, ∆f = 2MHz),
IF = 153MHz, unless otherwise noted. Test circuit shown in Figure 1.
Conversion Gain, IIP3 and NF
vs RF Frequency (High Side LO)
33
IIP3
85°C
25°C
–40°C
30
27
24
21
18
15
NF
12
9
GC
6
3
31
85°C
25°C
–40°C
27
24
21
NF
12
350
400 450 500 550
RF FREQUENCY (MHz)
600
6
GC
0
300
650
350
400 450 500 550
RF FREQUENCY (MHz)
600
IIP3
28
12
GC
25
3
22
RF = 400MHz
LOW SIDE LO
2
HIGH SIDE LO
19
16
NF
LOW SIDE LO
HIGH SIDE LO
350
400 450 500 550
RF FREQUENCY (MHz)
600
1
7
–6
650
–4
–2
0
2
4
LO INPUT POWER (dBm)
Conversion Gain, IIP3 and SSB
NF vs Temperature
18
12
NF
9
6
3
RF-IF
–20
40
LO-IF
GC
20
23
20
17
P1dB
14
1
NF
–40
300
350
IFOUT
0
–10
–20
–30
RF1 = 399MHz
RF2 = 401MHz
LO = 553MHz
–40
–50
–60
–70
–80
LO-RF
5551 G39
3
RF = 400MHz
LOW SIDE LO
HIGH SIDE LO 2
20
60
–30
0
–40 –25 –10 5 20 35 50 65 80 95 110
CASE TEMPERATURE (°C)
26
10
–10
LO LEAKAGE (dBm)
21
GC
5551 G38
RF-LO
RF = 400MHz
LOW SIDE LO
HIGH SIDE LO
4
29
0
8
2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6
VCC SUPPLY VOLTAGE (V)
80
IIP3
24
IIP3
2-Tone IF Output Power, IM3 and
IM5 vs RF Input Power
0
27
15
6
0
RF ISOLATION (dB)
IIP3 (dBm), NF (dB), GC (dB)
30
32
LO Leakage and RF Isolation
36
0
650
5
5551 G37
5551 G36
33
600
11
10
OUTPUT POWER/TONE (dBm)
10
300
4
IIP3 (dBm), P1dB (dBm), NF (dB)
NF (dB), IIP3 (dBm)
INPUT P1dB (dBm)
35
13
11
400 450 500 550
RF FREQUENCY (MHz)
GC (dB)
13
350
1
38
GC (dB)
LOW POWER MODE
14
2
NF
Conversion Gain, IIP3, P1dB
and NF vs Supply Voltage
5
31
16
3
5551 G35
34
NORMAL POWER MODE
17
4
7
300
650
37
19
5
GC
16
400MHz Conversion Gain, IIP3
and NF vs LO Power
20
6
19
5551 G34
Input P1dB vs Frequency
15
22
10
5551 G33
18
LOW POWER MODE
ISEL = HIGH
LOW SIDE LO
HIGH SIDE LO
13
9
3
0
300
7
25
18
15
8
IIP3
28
IIP3
30
IIP3 (dBm), NF (dB)
36
33
IIP3 (dBm), NF (dB), GC (dB)
36
Conversion Gain, IIP3 and NF
vs RF Frequency
GC (dB)
IIP3 (dBm), NF (dB), GC (dB)
Conversion Gain, IIP3 and NF
vs RF Frequency (Low Side LO)
400 450 500 550 600
LO/RF FREQUENCY (MHz)
0
650
5551 G40
–90
–10 –7
IM3
IM5
–4 –1 2
5
8 11 14
RF INPUT POWER (dBm/TONE)
17
5551 G41
5551fa
For more information www.linear.com/LTC5551
9
LTC5551
Typical AC Performance Characteristics
500MHz to 1100MHz application.
VCC = 3.3V, EN = High, ISEL = Low, TC = 25°C, PLO = 0dBm, PRF = 0dBm (0dBm/tone for two-tone IIP3 tests, ∆f = 2MHz),
IF = 153MHz, unless otherwise noted. Test circuit shown in Figure 1.
31
33
30
85°C
25°C
–40°C
NF
24
21
18
15
NF
12
6
GC
0
500
1100
IIP3
3
RF = 850MHz 2
LOW SIDE LO
HIGH SIDE LO
1
NF
–6
–4
–2
0
2
4
LO INPUT POWER (dBm)
6
5551 G46
0
GC (dB)
NF (dB), IIP3 (dBm)
4
GC
20
8
19
600
700
800
900 1000
RF FREQUENCY (MHz)
NF (dB), IIP3 (dBm)
14
13
12
4
GC
26
3
23
20
RF = 850MHz 2
LOW SIDE LO
HIGH SIDE LO
1
17
–6
–4
–2
0
2
4
LO INPUT POWER (dBm)
5551 G45
26
GC
23
20
2
P1dB
17
14
1
NF
5551 G47
2-Tone IF Output Power, IM3 and
IM5 vs RF Input Power
LO Leakage and RF Isolation
80
0
20
60
–10
RF-IF
–20
40
LO-IF
–30
20
LO-RF
–40
500
600
IFOUT
10
RF-LO
LO LEAKAGE (dBm)
IIP3 (dBm), NF (dB), GC (dB)
6
RF = 850MHz 4
LOW SIDE LO
HIGH SIDE LO
3
IIP3
29
0
8
2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6
VCC SUPPLY VOLTAGE (V)
0
RF ISOLATION (dB)
10
32
5551 G46
Conversion Gain, IIP3 and SSB
NF vs Temperature
5551 G48
5
11
NF
8
0
1100
38
29
11
1100
39
36
IIP3
33
30
27
RF = 850MHz
24
LOW SIDE LO
21
HIGH SIDE LO
18
15
12
NF
9
6
GC
3
0
–40 –25 –10 5 20 35 50 65 80 95 110
CASE TEMPERATURE (°C)
900 1000
700
800
RF FREQUENCY (MHz)
35
IIP3
14
LOW SIDE LO
HIGH SIDE LO
700
800
900 1000
RF FREQUENCY (MHz)
600
1
GC (dB)
LOW POWER MODE
600
2
5551 G44
5
32
17
11
3
Conversion Gain, IIP3, P1dB
and NF vs Supply Voltage
38
35
NORMAL POWER MODE
4
NF
7
500
1100
GC (dB)
INPUT P1dB (dBm)
5
35
32
29
26
23
5
GC
16
10
IIP3 (dBm), P1dB (dBm), NF (dB)
38
17
14
11
15
19
850MHz Conversion Gain, IIP3
and NF vs LO Power
20
16
22
5551 G43
Input P1dB vs RF Frequency
18
6
LOW POWER MODE
ISEL = HIGH
LOW SIDE LO
HIGH SIDE LO
13
9
3
700
800
900 1000
RF FREQUENCY (MHz)
7
IIP3
25
OUTPUT POWER/TONE (dBm)
600
85°C
25°C
–40°C
27
GC
8
28
IIP3 (dBm), NF (dB)
IIP3
IIP3
5551 G42
10
500
Conversion Gain, IIP3 and NF
vs RF Frequency
36
IIP3 (dBm), NF (dB), GC (dB)
39
36
33
30
27
24
21
18
15
12
9
6
3
0
500
Conversion Gain, IIP3 and NF
vs RF Frequency (High Side LO)
GC (dB)
IIP3 (dBm), NF (dB), GC (dB)
Conversion Gain, IIP3 and NF
vs RF Frequency (Low Side LO)
0
–10
–20
–30
–40
RF1 = 849MHz
RF2 = 851MHz
LO = 1003MHz
–50
–60
–70
IM3
IM5
–80
700
800
900 1000
LO/RF FREQUENCY (MHz)
0
1100
5551 G49
–90
–10 –7
–4 –1 2
5
8 11 14
RF INPUT POWER (dBm/TONE)
17
5551 G50
5551fa
For more information www.linear.com/LTC5551
LTC5551
Typical AC Performance Characteristics
2300MHz to 3500MHz application.
VCC = 3.3V, EN = High, ISEL = Low, TC = 25°C, PLO = 0dBm, PRF = 0dBm (0dBm/tone for two-tone IIP3 tests, ∆f = 2MHz),
IF = 153MHz, unless otherwise noted. Test circuit shown in Figure 1.
Conversion Gain, IIP3 and NF
vs RF Frequency (High Side LO)
39
36
35
33
23
19
NF
11
7
GC
3
–1
2.3
2.5
3.3
85°C
25°C
–40°C
24
21
18
15
NF
12
6
2.5
2.7
2.9
3.1
RF FREQUENCY (GHz)
39
NORMAL POWER MODE
NF (dB), IIP3 (dBm)
INPUT P1dB (dBm)
14
13
12
LOW SIDE LO
HIGH SIDE LO
2.7
2.9
3.1
RF FREQUENCY (GHz)
3.3
30
24
RF = 2.7GHz
3
LOW SIDE LO
HIGH SIDE LO
21
2
27
GC
18
12
9
3.5
1
NF
–6
–4
–2
0
2
4
LO INPUT POWER (dBm)
24
21
1
P1dB
18
15
0
NF
5551 G56
75
20
60
LO LEAKAGE (dBm)
–10
RF-IF
45
LO-IF
–30
–40
IFOUT
10
RF-LO
–20
2
GC
2-Tone IF Output Power, IM3 and
IM5 vs RF Input Power
0
NF
27
–1
9
2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6
VCC SUPPLY VOLTAGE (V)
0
30
15
LO-RF
GC
RF ISOLATION (dB)
IIP3 (dBm), NF (dB), GC (dB)
6
3
RF = 2.7GHz
LOW SIDE LO
HIGH SIDE LO
30
LO Leakage and RF Isolation
IIP3
RF = 2700MHz
LOW SIDE LO
HIGH SIDE LO
IIP3
33
5551 G55
Conversion Gain, IIP3 and SSB
NF vs Temperature
–3
3.5
3.3
4
12
5551 G54
39
36
33
30
27
24
21
18
15
12
9
6
3
0
–40 –25
3.1
2.7
2.9
RF FREQUENCY (GHz)
36
4
15
2.5
2.5
GC (dB)
15
–2
NF
39
GC (dB)
16
–1
Conversion Gain, IIP3, P1dB
and NF vs Supply Voltage
5
33
LOW POWER MODE
0
5551 G53
IIP3
36
18
11
16
7
2.3
3.3
1
LOW POWER MODE
ISEL = HIGH
LOW SIDE LO
HIGH SIDE LO
2.7GHz Conversion Gain, IIP3 and
NF vs LO Power
20
10
2.3
19
2
5551 G52
Input P1dB vs RF Frequency
17
GC
22
10
GC
5551 G51
19
3
13
9
0
2.3
3.5
4
IIP3
25
27
3
2.7
2.9
3.1
RF FREQUENCY (GHz)
5
28
OUTPUT POWER/TONE (dBm)
15
30
IIP3 (dBm), NF (dB)
85°C
25°C
–40°C
31
IIP3
IIP3 (dBm), P1dB (dBm), NF (dB)
27
IIP3 (dBm), NF (dB), GC (dB)
IIP3
31
Conversion Gain, IIP3 and NF
vs RF Frequency
GC (dB)
IIP3 (dBm), NF (dB), GC (dB)
Conversion Gain, IIP3 and NF vs
RF Frequency (Low Side LO)
0
–10
–20
–30
–40
RF1 = 2699MHz
RF2 = 2701MHz
LO = 2547MHz
–50
–60
IM3
–70
IM5
–80
–10 5 20 35 50 65 80 95 110
CASE TEMPERATURE (°C)
5551 G57
–50
2.3
2.5
2.9
3.1
3.3
2.7
LO/RF FREQUENCY (GHz)
0
3.5
5551 G58
–90
–8
–5
–2
1
4
7
10 13
RF INPUT POWER (dBm/TONE)
16
5551 G59
5551fa
For more information www.linear.com/LTC5551
11
LTC5551
Pin Functions
TP (Pin 1): Test Point. It is used for manufacture measurement only. It is recommended to be connected to ground.
a regulated 2.5V to 3.6V supply, with bypass capacitors
located close to the pin. Typical current consumption is
70mA through these pins.
RF (Pin 2): Single-Ended Input for the RF Signal. This pin
is internally connected to the primary side of the RF input
transformer, which has low DC resistance to ground. A
series DC-blocking capacitor should be used to avoid
damage to the integrated transformer when DC voltage
is present at the RF input. The RF input impedance is
matched under the condition that the LO input is driven
with a 0dBm ±6dB source between 0.2GHz and 3.5GHz.
ISEL (Pin 8): Low Power Select Pin. When this pin is pulled
low (<0.3V) or left open, the mixer is biased at the normal
current level for best RF performance. When greater than
1.2V is applied, the mixer operates at reduced current mode,
which provides reasonable performance at lower power
consumption. This pin has an internal pull-down resistor.
LO (Pin 10): Single-Ended Input for the Local Oscillator.
This pin is internally connected to the primary side of the
RF input transformer, which has low DC resistance to
ground. A series DC blocking capacitor should be used
to avoid damage to the integrated transformer when DC
voltage is present at the LO input.
CT (Pin 3): RF Transformer Secondary Center-Tap. This
pin must be connected to ground with minimum parasitic
resistance and inductance to complete the Mixer’s DC
current path. Typical DC current is 80mA with LO disabled
and 134mA when LO signal is applied.
GND (Pins 4, 9, 11, 13, Exposed Pad Pin 17): Ground.
These pins must be soldered to the RF ground plane on
the circuit board. The exposed pad metal of the package
provides both electrical contact to ground and good thermal
contact to the printed circuit board.
TEMP (Pin 12): Temperature Sensing Diode. This pin is
connected to the anode of a diode that may be used to
measure the die temperature, by forcing a current and
measuring the voltage.
IF – (Pin 14) and IF + (Pin 15): Open-Collector Differential
Outputs for the IF Amplifier. These pins must be connected
to a DC supply through impedance matching inductors, or
a transformer center-tap. Typical DC current consumption
is 67mA into each pin.
EN (Pin 5): Enable Pin. When the input voltage is greater
than 1.2V, the mixer is enabled. When the input voltage is
less than 0.3V or left open, the mixer is disabled. Typical
input current is less than 30μA. This pin has an internal
pull-down resistor.
IFBIAS (Pin 16): This Pin Allows Adjustment of the IF
Amplifier Current. Typical DC voltage is 2.1V. This pin
should be left floating for optimum performance.
VCC (Pins 6, 7): Power Supply Pins. These pins are internally connected and must be externally connected to
Block Diagram
16
15
14
IFBIAS IF +
17
IF –
EXPOSED
PAD
IF
AMP
2
3
TEMP
LO
RF
LO
AMP
12
10
CT
BIAS
5
EN
6
VCC
7
VCC
6
ISEL
5551 BD
GND PINS ARE NOT SHOWN
12
5551fa
For more information www.linear.com/LTC5551
LTC5551
Test Circuit
T1
4:1
IFOUT
153MHz
50Ω
C9
L1
L2
R1
R2
C8
VCC
C4
C5
16
15
IFBIAS
1 GND
14
IF+
13
IF –
GND
TEMP 12
LTC5551
C1
RFIN
50Ω
2 RF
X1
GND 11
X2
17
GND
C2
LO 10
3 CT
C3
4 GND
EN
0V TO 3.3V
GND 9
EN
VCC
VCC
ISEL
5
6
7
8
VCC
3.1V TO 3.5V
C6
C7
ISEL
0V TO 3.3V
5551 F01
RF
0.015"
GND TBD
BOARD
BIAS STACK-UP
GND (NELCO N4000-13)
0.062"
0.015"
APPLICATION
LOIN
50Ω
RF MATCH
LO MATCH
IF TRANSFORMER
RF (MHz)
LO
X1
C1
X2
C2
C3
T1
VENDOR
300 to 650
HS
15nH
15pF
15pF
15pF
8.2pF
TC4-1W-7ALN+
Mini-Circuits
500 to 1100
HS
13nH
6.8pF
4.7pF
8.2pF
2.2pF
WBC4-6TLB
Coilcraft
1100 to 2700
LS, HS
7.5nH
2.2pF
–
3.9pF
–
TC4-1W-7ALN+
Mini-Circuits
2300 to 3500
LS, HS
1.2pF
22pF
2.2nH
3.9pF
–
TC4-1W-7ALN+
Mini-Circuits
REF DES
VALUE
SIZE
VENDOR
REF DES
VALUE
SIZE
VENDOR
C4, C6
0.56µF
0603
Murata
R1, R2
475Ω, 1%
0402
Vishay
C5, C7
22pF
0402
AVX
L1, L2
470nH, 2%
0603
Coilcraft 0603LS
C8, C9
1nF
0402
AVX
Figure 1. Standard Downmixer Test Circuit Schematic (153MHz IF)
5551fa
For more information www.linear.com/LTC5551
13
LTC5551
Applications Information
Introduction
The LTC5551 consists of a high linearity double-balanced
mixer core, IF buffer amplifier, LO buffer amplifier and
bias/enable circuits. See the Block Diagram section for a
description of each pin function. The RF and LO inputs
are single-ended. The IF output is differential. Low side or
high side LO injection can be used. The evaluation circuit,
shown in Figure 1, utilizes bandpass IF output matching
and an IF transformer to realize a 50Ω single-ended IF
output. The evaluation board layout is shown in Figure 2.
For the RF input to be matched, the LO input must be
driven. Using components listed in Figure 1, the RF input
can be matched from 300MHz to 3.5GHz. The measured
RF input return loss is shown in Figure 4 for LO frequencies of 0.5GHz, 1.0GHz. 1.8GHz and 2.8GHz. These LO
frequencies correspond to the lower, middle and upper
values of the LO range.
The RF input impedance and input reflection coefficient,
versus RF frequency, is listed in Table 1. The reference
plane for this data is Pin 2 of the IC, with no external
matching, and the LO is driven at 1.8GHz.
LTC5551
TO MIXER
C1
RFIN
2
X1
RF
X2
3
CT
5551 F03
Figure 3. RF Input Schematic
Figure 2. Evaluation Board Layout
RF Input
The secondary winding of the RF transformer is internally connected to the mixer core. The center-tap of the
transformer secondary is connected to Pin 3 (CT). Pin 3
needs to be connected to ground with a minimum parasitic
resistance and inductance.
RF PORT RETURN LOSS (dB)
5
The mixer’s RF input, shown in Figure 3, is connected
to the primary winding of an integrated transformer. A
50Ω match can be realized with a π-network as shown in
Figures 1 and 3. The primary side of the RF transformer
is DC-grounded internally and the DC resistance of the
primary is approximately 4Ω. A DC blocking capacitor is
needed if the RF source has DC voltage present.
14
0
10
LO = 0.5GHz
LO = 1.0GHz
LO = 1.8GHz
LO = 2.8GHz
1100MHz to
2700MHz
MATCHING
15
20
25
30
500MHz to
1100MHz
MATCHING
300MHz to 650MHz
MATCHING
2300MHz to
3500MHz
MATCHING
35
0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.3 3.6
RF FREQUENCY (GHz)
5551 F04
Figure 4. RF Input Return Loss
5551fa
For more information www.linear.com/LTC5551
LTC5551
Applications Information
Table 1. RF Input Impedance and S11
(at Pin 2, No External Matching, LO Input Driven at 1.8GHz)
S11
FREQUENCY
(GHz)
INPUT
IMPEDANCE
MAG
ANGLE
0.3
7.6 + j8.4
0.74
160.4
0.7
11.7 + j15.2
0.65
144.5
1.1
17.7 + j 22.2
0.55
127.4
1.5
29.3 + j27.8
0.41
107.4
1.9
46.7 + j21.8
0.22
85.8
2.3
49.6 – j1.3
0.01
–106.3
2.7
31.1 – j9.0
0.26
–148.2
3.1
18.2 – j1.8
0.47
–175.2
3.5
11.8 + j8.4
0.63
159.8
LO Input
The mixer’s LO input circuit, shown in Figure 5, consists
of a balun transformer and a two-stage high speed limiting
differential amplifier to drive the mixer core. The LTC5551’s
LO amplifiers are optimized for the 200MHz to 3.5GHz
LO frequency range. LO frequencies above or below this
frequency range may be used with degraded performance.
The mixer’s LO input is directly connected to the primary
winding of an integrated transformer. The LO is 50Ω
matched from 1GHz to 3.5GHz with a single 3.9pF series
capacitor on the input. Matching to LO frequencies below
1GHz is easily accomplished by adding shunt capacitor
C3 shown in Figure 5. Measured LO input return loss is
shown in Figure 6.
The nominal LO input level is 0dBm although the limiting
amplifiers will deliver excellent performance over a ±6dB
input power range. LO input power of –9dBm may be used
with slightly degraded performance.
The LO input impedance and input reflection coefficient,
versus frequency, is shown in Table 2.
Table 2. LO Input Impedance vs Frequency
(at Pin 10, No External Matching)
INPUT
IMPEDANCE
MAG
ANGLE
0.3
4.8 + j12.0
0.84
152.7
0.7
13.4 + j28.1
0.67
118.5
1.1
32.7 + j39.1
0.47
88.6
1.5
56.8 + j31.1
0.29
61.5
1.9
62.8 + j9.3
0.14
31.4
2.3
54.1 – j1.4
0.04
–18.3
2.7
45.1 – j1.4
0.05
–163.6
3.1
39.8 + j3.6
0.12
158.6
3.5
37.2 + j10.4
0.19
134.1
0
LO BUFFER
LO
10
TO
MIXER
C2
C3
4mA
BIAS
5
EN
6
VCC
7
LOIN
LO PORT RETURN LOSS (dB)
LTC5551
S11
FREQUENCY
(GHz)
5
C2 = 15pF, C3 = 8.2pF
C2 = 8.2pF, C3 = 2.2pF
C2 = 3.9pF, C3 OPEN
10
15
20
25
0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.3 3.6
LO FREQUENCY (GHz)
VCC
5551 F05
5551 F06
Figure 5. LO Input Schematic
Figure 6. LO Input Return Loss
5551fa
For more information www.linear.com/LTC5551
15
LTC5551
Applications Information
IF Output
The IF amplifier, shown in Figure 7, has differential opencollector outputs (IF+ and IF –), and a pin for modifying the
internal bias (IFBIAS). The IF outputs must be biased at the
supply voltage (VCC), which is applied through matching
inductors L1 and L2. Alternatively, the IF outputs can be
biased through the center tap of a transformer. Each IF
output pin draws approximately 67mA of DC supply current (134mA total). For the highest performance, high-Q
wire-wound chip inductors are recommended for L1 and
L2. Low cost multilayer chip inductors may be substituted,
with a slight degradation in performance.
C9
L1
16
15
IF+
IFBIAS
IF –
CIF
5551 F08
Figure 8. IF Output Small-Signal Model
Table 3. IF Output Impedance vs Frequency
954 || –j1442 (1.2pF)
140
950 || –j848 (1.2pF)
190
945 || –j681 (1.2pF)
L2
240
942 || –j539 (1.2pF)
R2
380
938 || –j338 (1.2pF)
456
926 || –j281 (1.2pF)
VCC
LTC5551
RIF
90
C8
R1
14
DIFFERENTIAL OUTPUT
IMPEDANCE (RIF || XIF (CIF))
4:1
R3
(OPTION TO
REDUCE
DC POWER)
IF +
FREQUENCY (MHz)
T1
IFOUT
15
LTC5551
C4
14
IF –
Transformer-Based Bandpass IF Matching
VCC
4mA
The IF output can be matched using the bandpass IF
matching shown in Figures 1 and 7. L1 and L2 resonate
with the internal IF output capacitance at the desired IF
frequency. The value of L1, L2 is calculated as follows:
IF
AMP
BIAS
5551 F07
Figure 7. IF Amplifier Schematic with
Transformer-Based Bandpass Match
For optimum single-ended performance, the differential IF
outputs must be combined through an external IF transformer or discrete IF balun circuit. The evaluation board
(see Figures 1 and 2) uses a 4:1 ratio IF transformer for
impedance transformation and differential to single-ended
transformation. It is also possible to eliminate the IF transformer and drive differential filters or amplifiers directly.
The IF output impedance can be modeled as 950Ω in
parallel with 1.2pF at IF frequencies. An equivalent smallsignal model is shown in Figure 8. Frequency-dependent
differential IF output impedance is listed in Table 3. This
data is referenced to the package pins (with no external
components) and includes the effects of IC and package
parasitics.
16
L1, L2 = 1/[(2 π fIF)2 • 2 • CIF]
where CIF is the internal IF capacitance (listed in Table 3).
Values of L1 and L2 are tabulated in Figure 1 for various
IF frequencies.
For IF Frequency below 80MHz, the inductor values become
unreasonably high and the high pass impedance matching
network described in a later section is preferred, due to
its lower inductor values.
Table 4 summarizes the optimum IF matching inductor
values vs IF center frequency, to be used in the standard
downmixer test circuit shown in Figure 1. The inductor
values listed are less than the ideal calculated values
due to the additional capacitance of the 4:1 transformer.
Measured IF output return losses are shown in Figure 9.
5551fa
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LTC5551
Applications Information
Table 4. Bandpass Matching Elements Values vs IF Frequency
Highpass IF Matching
L1, L2 vs IF Frequencies
The highpass IF matching circuits shown in Figure 10 can
be used when higher conversion gain than that from the
standard demoboard is desired. The highpass matching
network will have less IF bandwidth than the bandpass
matching. It also use smaller inductance values; an
advantage when designing for IF center frequency well
lower than 80MHz.
IF (MHz)
L1, L2 (nH)
COMMENTS
120
810
Coilcraft 0603 LS
153
470
Coilcraft 0603 LS
240
180
Coilcraft 0603 CS
305
120
Coilcraft 0603 CS
380
56
Coilcraft 0603 CS
456
33
Coilcraft 0603 CS
The resistors R1 and R2 which are connected between the
IF+ and IF– is used to assist the IF impedance matching. A
lower value of R1, R2 will help improve the IF return loss
and broaden the IF bandwidth. However, it will results in
lower conversion gain with minor impact to linearity and
noise figure performances.
Other 4:1 transformers can be used to replace the TC41-7ALN+ that is used in the standard demoboards. The
insertion loss and parasitics of the transformer will impact
the overall circuit performance. For IF frequency higher
than 300MHz, the TC4-1-17LN+ from Mini-Circuits or the
WBC4-6TLB from Coilcraft is preferred.
Referring to the small-signal output network schematic in
Figure 10, the reactive matching element values (L1, L2,
C8 and C9) are calculated using the following equations.
The source resistance (RS) is the parallel combination of
external resistors R1 + R2 and the internal IF resistance,
RIF taken from Table 3. The differential load resistance
(RL) is typically 200Ω, but can be less. CIF, the IF output
capacitance, is taken from Table 3. Choosing RS in the
380Ω to 450Ω range will yield power conversion gains
around 4dB.
RETURN LOSS (dB)
5
15
L1, L2 = 470nH
L1, L2 = 120nH
L1, L2 = 56nH
L1, L2 = 33nH
20
25
50 100 150 200 250 300 350 400 450 500
IF FREQUENCY (MHz)
5551 F09
(R1=R2)
(RS /RL −1)
YL =Q /RS + (ωIF •CIF )
L1,L2 =1/ (2 • YL • ωIF )
C7,C8 = 2 / (Q •RL • ωIF )

(RS >RL )
Q=
0
10
RS =RIF 2 •R1
To demonstrate the highpass impedance transformer
output matching, these equations were used to calculate
the element values for a 80MHz IF frequency and 200Ω
differential load resistance. The measured performance
with L1, L2 = 330nH, C8, C9 = 15pF is shown in Figure 11.
The test conditions are: PRF = –6dBm, PLO = 0dBm with
low side LO injection.
Figure 9. IF Output Return Loss Bandpass
Matching with 4:1 Transformer
5551fa
For more information www.linear.com/LTC5551
17
LTC5551
Applications Information
T1
4:1
C9
IFOUT
L1
L2
R1
R2
C8
VCC
C4
15
LTC5551
14
IF+
IF –
RIF
CIF
5551 F10
Figure 10. IF Output Circuit for Highpass Matching Element Value Calculations
38
10
36
9
8
IIP3
32
7
30
6
26
5
4
24
22
20
1.1
GC (dB)
IIP3 (dBm)
34
R1, R2 OPEN
R1, R2 = 1kΩ
1.3
GC
1.5 1.7 1.9 2.1 2.3
RF FREQUENCY (GHz)
3
2.5
2
2.7
5551 F11
Figure 11. Performance Using 80MHz
Highpass IF Matching Network
18
5551fa
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LTC5551
Applications Information
Wideband Differential IF Output
Wide IF bandwidth and high input 1dB compression are
obtained by reducing the IF output resistance with resistors
R1 and R2. This will reduce the mixer’s conversion gain,
but will not degrade the IIP3 or noise figure.
The IF matching shown in Figure 12 uses 249Ω resistors
and 470nH supply chokes to produce a wideband 200Ω
differential output. This differential output is suitable for
driving a wideband differential amplifier, filter, or a wideband 4:1 transformer.
The complete test circuit, shown in Figure 13, uses resistive impedance matching attenuators (L-pads) on the
evaluation board to transform each 100Ω IF output to
50Ω. An external 0°/180° power combiner is then used to
convert the 100Ω differential output to 50Ω single-ended,
to facilitate measurement.
Measured conversion gain and IIP3 at the 200Ω differential
output are plotted in Figure 14. As shown, the conversion
gain is flat within 1dB over the 50MHz to 490MHz IF output
frequency range.
5
38
36
IIP3
34
249Ω
IF+
100Ω
470nH
249Ω
3
28
26
20
0
50 90 130 170 210 250 290 330 370 410 450 490
IF FREQUENCY (MHz)
18
5551 F12
270pF
1
22
100Ω
470nH
2
GC
24
VCC
IF–
30
GC (dB)
LTC5551
IIP3 (dBm)
200Ω
LOAD
270pF
4
32
5551 F14
Figure 12. Wideband 200Ω Differential Output
LO
1.8GHz
0dBm
Figure 14. Conversion Gain and IIP3 vs IF Output
Frequency for Wideband 200Ω Differential IF
L-PADS AND 180° COMBINER
FOR 50Ω SINGLE-ENDED MEASUREMENT
3.9pF
LO
270pF
LTC5551
RF
1.85GHz
TO
2.29GHz
2.2pF
IF+
LO
249Ω
7.5nH
IF
EN
71.5Ω
470nH
IFOUT
200Ω
RF
EN
69.8Ω
249Ω
IF–
BIAS
IF+
50Ω
22pF
470nH
1MHz TO 500MHz
COMBINER
0°
OUT
IF–
69.8Ω
270pF
50Ω
180°
IFOUT
50Ω
71.5Ω
VCC
3.3V
10nF
0.56µF
5551 F13
Figure 13. Test Circuit for Wideband 200Ω Differential Output
5551fa
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19
LTC5551
Applications Information
The IFBIAS pin (Pin 16) is available for reducing the DC
current consumption of the IF amplifier, at the expense of
reduced performance. This pin should be left open-circuited
for optimum performance. The internal bias circuit produces a 4mA reference for the IF amplifier, which causes
the amplifier to draw approximately 134mA. If resistor R3
is connected to Pin 16 as shown in Figure 7, a portion of
the reference current can be shunted to ground, resulting
in reduced IF amplifier current. For example, R3 = 1kΩ will
shunt away 1.5mA from Pin 16 and the IF amplifier current will be reduced to approximately 90mA. The nominal,
open-circuit DC voltage at Pin 16 is 2.1V. Table 5 lists RF
performance at 1950MHz vs IF amplifier current.
Table 5. Mixer Performance with Reduced IF Amplifier Current
(RF = 1950MHz, Low Side LO, IF = 153MHz, VCC = 3.3V)
R3
(kΩ)
ICC
(mA)
GC
(dB)
IIP3
(dBm)
P1dB
(dBm)
NF
(dB)
OPEN
204
2.4
35.5
18.0
9.7
4.7
194
2.4
35.0
17.9
9.4
2.2
186
2.4
34.2
17.8
9.2
1.0
164
2.4
31.9
17.3
LTC5551
VCC
7
ISEL
8
BIAS
5551 F15
Figure 15. ISEL Interface Schematic
LTC5551
6
5
VCC
EN
BIAS
5551 F16
Figure 16. Enable Input Circuit
8.7
(RF = 1950MHz, High Side LO, IF = 153MHz, VCC = 3.3V)
R3
(kΩ)
ICCIF
(mA)
GC
(dB)
IIP3
(dBm)
P1dB
(dBm)
NF
(dB)
OPEN
204
2.4
33.0
17.9
10.5
4.7
194
2.3
32.6
17.8
10.2
ISEL
ICC
(mA)
GC
(dB)
IIP3
(dBm)
P1dB
(dBm)
NF
(dB)
Table 6. Performance Comparison – Low Power vs High Power
Mode RF = 1950MHz, Low Side LO, IF = 153MHz, EN = High
2.2
186
2.3
32.1
17.6
9.9
Low
204
2.4
35.5
18.0
9.7
1.0
164
2.3
30.5
17.0
9.4
High
139
2.4
29.3
16.7
8.3
Low Power Mode
Enable Interface
The LTC5551 can be set to low power mode using a digital
voltage applied to the ISEL pin (Pin 8). This allows the
flexibility to reduce current when lower RF performance is
acceptable. Figure 15 shows a simplified schematic of the
ISEL pin interface. When ISEL is set low (<0.3V), the mixer
operates at maximum DC current. When ISEL is set high
(>1.2V), the DC current is reduced, thus reducing power
consumption. When floating, the ISEL is pulled low by
an internal pull-down resistor, and operates at maximum
supply current. The performance in low power mode and
nominal power mode are compared in Table 6.
Figure 16 shows a simplified schematic of the EN pin interface. To enable the chip, the EN voltage must be higher
than 1.2V. The EN voltage at the pin should never exceed
the power supply voltage (VCC) by more than 0.3V. If this
should occur, the supply current could be sourced through
the ESD diode, potentially damaging the IC.
20
If the EN pin is left floating, its voltage will be pulled low by
the internal pull-down resistor and the chip will be disabled.
5551fa
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LTC5551
Applications Information
Temperature Diode
Supply Voltage Ramping
The LTC5551 provides an on-chip diode at Pin 12 (TEMP)
for chip temperature measurement. Pin 12 is connected to
the anode of an internal ESD diode with its cathode connected to internal ground. The chip temperature can be
measured by injecting a constant DC current into Pin 12
and measuring its DC voltage. The voltage vs temperature
coefficient of the diode is about –1.72mV/°C with 10µA
current injected into the TEMP pin. Figure 17 shows a
typical temperature-voltage behavior when 10µA and 80µA
currents are injected into Pin 12.
Fast ramping of the supply voltage can cause a current
glitch in the internal ESD protection circuits. Depending on
the supply inductance, this could result in a supply voltage transient that exceeds the maximum rating. A supply
voltage ramp time of greater than 1ms is recommended.
TEMPERATURE DIODE VOLTAGE (mV)
900
850
800
Table 7. IF Output Spur Levels (dBc)
80µA
700
650
600
550
500
450
400
–40
–20
0
20
40
60
TEMPERATURE (°C)
Mixer spurious output levels versus harmonics of the
RF and LO are tabulated in Table 7. The spur levels were
measured on a standard evaluation board using the test
circuit shown in Figure 1. The spur frequencies can be
calculated using the following equation:
fSPUR = (M • fRF)–(N • fLO)
10µA
750
Spurious Output Levels
80
100
5551 F17
Figure 17. TEMP Diode Voltage vs Junction Temperature (TJ)
RF = 1950MHz, PRF = 0dBm, PLO = 0dBm, IF = 153MHz, Low Side LO,
VCC = 3.3V, EN = High, ISEL = Low, TC = 25°C
N
0
1
2
3
4
5
6
7
8
9
0
–26 –36 –40 –40 –61 –70 –57 –60 *
1 –28 0 –43 –26 –60 –43 –64 –49 –62 –63
2 –83 –66 –70 –69 –83 *
* –81 * –79
M
*
*
*
*
*
*
3
* –81 *
*
4
*
*
*
*
*
*
*
*
*
*
5
*
*
*
*
*
*
*
*
*
*
6 –84 *
*
*
*
*
*
*
*
*
7 –82 *
* –84 *
*
*
*
*
*
*Less than –85dBc
5551fa
For more information www.linear.com/LTC5551
21
LTC5551
Package Description
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
UF Package
16-Lead Plastic QFN (4mm × 4mm)
(Reference LTC DWG # 05-08-1692 Rev Ø)
0.72 ±0.05
4.35 ±0.05
2.15 ±0.05
2.90 ±0.05 (4 SIDES)
PACKAGE OUTLINE
0.30 ±0.05
0.65 BSC
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS
BOTTOM VIEW—EXPOSED PAD
4.00 ±0.10
(4 SIDES)
0.75 ±0.05
R = 0.115
TYP
15
PIN 1 NOTCH R = 0.20 TYP
OR 0.35 × 45° CHAMFER
16
0.55 ±0.20
PIN 1
TOP MARK
(NOTE 6)
1
2.15 ±0.10
(4-SIDES)
2
(UF16) QFN 10-04
0.200 REF
0.00 – 0.05
0.30 ±0.05
0.65 BSC
NOTE:
1. DRAWING CONFORMS TO JEDEC PACKAGE OUTLINE MO-220 VARIATION (WGGC)
2. DRAWING NOT TO SCALE
3. ALL DIMENSIONS ARE IN MILLIMETERS
4. 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
5. EXPOSED PAD SHALL BE SOLDER PLATED
6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION
ON THE TOP AND BOTTOM OF PACKAGE
22
5551fa
For more information www.linear.com/LTC5551
LTC5551
Revision History
REV
DATE
DESCRIPTION
A
12/13
Added U.S. Patent number
PAGE NUMBER
1
Corrected transformer T1 part number
13
5551fa
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 representation that the interconnection
of its circuits
as described
herein will not infringe on existing patent rights.
For more
information
www.linear.com/LTC5551
23
LTC5551
Typical Application
Wideband 100Ω Differential IF Output Matching
1nF
3.9pF
LO
2.2pF
RF
7.5nH
LTC5551
110Ω
560nH
2MHz TO
2000MHz
COMBINER
0°
IFOUT
50Ω
OUT
IF–
110Ω
VCC
560nH
1nF
IF–
50Ω
180°
39
6
36
5
33
4
30
3
27
2
IIP3
NORMAL POWER MODE
1
LOW POWER MODE
0
24
21
18
22pF
12
3.3V
10nF
0.56µF
–1
GC
15
GC (dB)
RF
1.85GHz
TO
2.51GHz
IF+
IF+
50Ω
IIP3 (dBm)
LO
1.8GHz
0dBm
Conversion Gain and IIP3 vs
IF Frequency (Low Side LO)
–2
–3
50 110 170 230 290 350 410 470 530 590 650 710
IF FREQUENCY (MHz)
5551 TA02b
5551 TA02a
Related Parts
PART NUMBER DESCRIPTION
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LT®5527
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LT5557
400MHz to 3.8GHz, 3.3V Downconverting Mixer
LTC559x
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Family
LTC5569
300MHz to 4GHz, 3.3V Dual Active
Downconverting Mixer
LTC554x
600MHz to 4GHz, 5V Downconverting Mixer Family
LT5578
400MHz to 2.7GHz Upconverting Mixer
LT5579
1.5GHz to 3.8GHz Upconverting Mixer
LTC5588-1
200MHz to 6GHz I/Q Modulator
LTC5585
700MHz to 3GHz Wideband I/Q Demodulator
Amplifiers
LTC6430-15
High Linearity Differential IF Amp
LTC6431-15
High Linearity Single-Ended IF Amp
LTC6412
31dB Linear Analog VGA
LT5554
Ultralow Distortion IF Digital VGA
RF Power Detectors
LT5538
40MHz to 3.8GHz Log Detector
LT5581
6GHz Low Power RMS Detector
LTC5582
40MHz to 10GHz RMS Detector
LTC5583
Dual 6GHz RMS Power Detector
ADCs
LTC2208
16-Bit, 130Msps ADC
LTC2153-14
14-Bit, 310Msps Low Power ADC
RF PLL/Synthesizer with VCO
LTC6946-1/
Low Noise, Low Spurious Integer-N PLL with
Integrated VCO
LTC6946-2/
LTC6946-3
24 Linear Technology Corporation
COMMENTS
2.3dB Gain, 23.5dBm IIP3 and 12.5dB NF at 1900MHz, 5V/78mA Supply
2.9dB Gain, 24.7dBm IIP3 and 11.7dB NF at 1950MHz, 3.3V/82mA Supply
8.5dB Gain, 26.5dBm IIP3, 9.9dB NF, 3.3V/380mA Supply
2dB Gain, 26.8dBm IIP3 and 11.7dB NF, 3.3V/180mA Supply
8dB Gain, >25dBm IIP3 and 10dB NF, 3.3V/200mA Supply
27dBm OIP3 at 900MHz, 24.2dBm at 1.95GHz, Integrated RF Output Transformer
27.3dBm OIP3 at 2.14GHz, NF = 9.9dB, 3.3V Supply, Single-Ended LO and RF Ports
31dBm OIP3 at 2.14GHz, –160.6dBm/Hz Noise Floor
>530MHz Demodulation Bandwidth, IIP2 Tunable to >80dBm, DC Offset Nulling
20MHz to 2GHz Bandwidth, 15.2dB Gain, 50dBm OIP3, 3dB NF at 240MHz
20MHz to 1.7GHz Bandwidth, 15.5dB Gain, 47dBm OIP3, 3.3dB NF at 240MHz
35dBm OIP3 at 240MHz, Continuous Gain Range –14dB to 17dB
48dBm OIP3 at 200MHz, 2dB to 18dB Gain Range, 0.125dB Gain Steps
±0.8dB Accuracy Over Temperature, –72dBm Sensitivity, 75dB Dynamic Range
40dB Dynamic Range, ±1dB Accuracy Over Temperature, 1.5mA Supply Current
±0.5dB Accuracy Over Temperature, ±0.2dB Linearity Error, 57dB Dynamic Range
Up to 60dB Dynamic Range, ±0.5dB Accuracy Over Temperature, >50dB Isolation
78dBFS Noise Floor, >83dB SFDR at 250MHz
68.8dBFS SNR, 88dB SFDR, 401mW Power Consumption
373MHz to 5.79GHz, –157dBc/Hz WB Phase Noise Floor, –100dBc/Hz Closed-Loop
Phase Noise
1630 McCarthy Blvd., Milpitas, CA 95035-7417
For more information www.linear.com/LTC5551
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com/LTC5551
5551fa
LT 1213 REV A • PRINTED IN USA
 LINEAR TECHNOLOGY CORPORATION 2013