LTC5591
1
5591f
IF
AMP ADC
IF
AMP
RF
1920MHz TO
1980MHz
LNA
BIAS
BIAS
SYNTH
VCCIF
3.3V or 5V
VCC
3.3V
22pF
22pF
2.7pF
1µF
22pF 1µF
22pF
150nH 150nH
1nF
1nF
190MHz
SAW
190MHz
BPF
IMAGE
BPF
RFA
RFB
ENA
LO
ENA
(0V/3.3V)
LO 1760MHz
4.7pF
VCCA
VCCB
IFA+IFA–
IFB+IFB–
5591 TA01a
LO
AMP
LO
AMP
ENB ENB
(0V/3.3V)
RF
1920MHz TO
1980MHz
LNA
2.7pF
IMAGE
BPF
IF
AMP
IF
AMP ADC
150nH 150nH
1nF
1nF 190MHz
SAW
190MHz
BPF
VCCIF VCC
Typical applicaTion
FeaTures DescripTion
Dual 1.3GHz to 2.3GHz
High Dynamic Range
Downconverting Mixer
The LTC
®
5591 is part of a family of dual-channel high dy-
namic range, high gain downconverting mixers covering
the 600MHz to 4.5GHz RF frequency range. The LTC5591
is optimized for 1.3GHz to 2.3GHz RF applications. The
LO frequency must fall within the 1.4GHz to 2.1GHz
range for optimum performance. A typical application is
a LTE or W-CDMA multichannel or diversity receiver with
a 1.7GHz to 2.2GHz RF input and low side LO.
The LTC5591’s high conversion gain and high dynamic
range enable the use of lossy IF filters in high selectivity
receiver designs, while minimizing the total solution cost,
board space and system-level variation. A low current
mode is provided for additional power savings and each
of the mixer channels has independent shutdown control.
Wideband Receiver
applicaTions
n Conversion Gain: 8.5dB at 1950MHz
n IIP3: 26.2dBm at 1950MHz
n Noise Figure: 9.9dB at 1950MHz
n 15.5dB NF Under 5dBm Blocking
n High Input P1dB
n 47dB Channel-to-Channel Isolation
n 1.25W Power Consumption at 3.3V
n Low Power Mode: <800mW Consumption
n Independent Channel Shutdown Control
n 50Ω Single-Ended RF and LO Inputs
n LO Input Matched In All Modes
n 0dBm LO Drive Level
n Small Package and Solution Size
n –40°C to 105°C Operation
n 3G/4G Wireless Infrastructure Diversity Receivers
(LTE, W-CDMA, TD-SCDMA, UMTS, GSM1800)
n Remote Radio Unit
n MIMO Multichannel Receivers
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.
High Dynamic Range Dual Downconverting Mixer Family
PART NUMBER RF RANGE LO RANGE
LTC5590 600MHz to 1.7GHz 700MHz to 1.5GHz
LTC5591 1.3GHz to 2.3GHz 1.4GHz to 2.1GHz
LTC5592 1.6GHz to 2.7GHz 1.7GHz to 2.5GHz
LTC5593 2.3GHz to 4.5GHz 2.1GHz to 4.2GHz
IF OUTPUT FREQUENCY (MHz)
160
6.0
GC (dB)
IIP3 (dBm), SSB NF (dB)
8.0
7.5
8.5
9.0
10.0
9.5
10.5
170 190
5591 TA01b
7.0
6.5
180 200 210 220
11.0
8
10
16
20
18
24
22
26
12
14
28
IIP3
GC
NF
LO = 1760MHz
PLO = 0dBm
RF = 1950 ±30MHz
TEST CIRCUIT IN FIGURE 1
Wideband Conversion Gain,
IIP3 and NF vs IF Frequency
(Mixer Only, Measured on
Evaluation Board)
LTC5591
2
5591f
pin conFiguraTionabsoluTe MaxiMuM raTings
Supply Voltage (VCC) ...............................................4.0V
IF Supply Voltage (VCCIF) .........................................5.5V
Enable Voltage (ENA, ENB) ..............–0.3V to VCC + 0.3V
Bias Adjust Voltage (IFBA, IFBB) .........–0.3V to VCC + 0.3V
Power Select Voltage (ISEL) .............–0.3V to VCC + 0.3V
LO Input Power (1GHz to 3GHz) .............................9dBm
LO Input DC Voltage ............................................... ±0.1V
RFA, RFB Input Power (1GHz to 3GHz) ................15dBm
RFA, RFB Input DC Voltage .................................... ±0.1V
Operating Temperature Range (TC) ........ –40°C to 105°C
Storage Temperature Range .................. –65°C to 150°C
Junction Temperature (TJ) .................................... 150°C
(Note 1)
24 23 22 21 20 19
7 8 9
TOP VIEW
25
GND
UH PACKAGE
24-LEAD (5mm × 5mm) PLASTIC QFN
10 11 12
6
5
4
3
2
1
13
14
15
16
17
18
RFA
CTA
GND
GND
CTB
RFB
ISEL
ENA
LO
GND
ENB
GND
GND
IFGNDA
IFA+
IFA–
IFBA
VCCA
GND
IFGNDB
IFB+
IFB–
IFBB
VCCB
TJMAX = 150°C, θJC = 7°C/W
EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB
orDer inForMaTion
LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE
LTC5591IUH#PBF LTC5591IUH#TRPBF 5591 24-Lead (5mm × 5mm) 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/
Dc elecTrical characTerisTics
PARAMETER CONDITIONS MIN TYP MAX UNITS
Power Supply Requirements (VCCA, VCCB, VCCIFA, VCCIFB)
VCCA, VCCB Supply Voltage (Pins 12, 19) 3.1 3.3 3.5 V
VCCIFA, VCCIFB Supply Voltage (Pins 9, 10, 21, 22) 3.1 3.3 5.3 V
Mixer Supply Current (Pins 12, 19) Both Channels Enabled 182 218 mA
IF Amplifier Supply Current (Pins 9, 10, 21, 22) Both Channels Enabled 200 240 mA
Total Supply Current (Pins 9, 10, 12, 19, 21, 22) Both Channels Enabled 382 458 mA
Total Supply Current – Shutdown ENA = ENB = Low 500 µA
Enable Logic Input (ENA, ENB) High = On, Low = Off
ENA, ENB Input High Voltage (On) 2.5 V
ENA, ENB Input Low Voltage (Off) 0.3 V
ENA, ENB Input Current –0.3V to VCC + 0.3V –20 30 µA
Turn On Time 0.9 µs
Turn Off Time 1 µs
VCC = 3.3V, VCCIF = 3.3V, ENA = ENB = High, ISEL = Low, TC = 25°C,
unless otherwise noted. Test circuit shown in Figure 1. (Note 2)
LTC5591
3
5591f
Dc elecTrical characTerisTics
VCC = 3.3V, VCCIF = 3.3V, ENA = ENB = High, ISEL = Low, TC = 25°C,
unless otherwise noted. Test circuit shown in Figure 1. (Note 2)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Low Current Mode Logic Input (ISEL) High = Low Power, Low = Normal Power Mode
ISEL Input High Voltage 2.5 V
ISEL Input Low Voltage 0.3 V
ISEL Input Current –0.3V to VCC + 0.3V –20 30 µA
Low Current Mode Current Consumption (ISEL = High)
Mixer Supply Current (Pins 12, 19) Both Channels Enabled 119 143 mA
IF Amplifier Supply Current (Pins 9, 10, 21, 22) Both Channels Enabled 120 144 mA
Total Supply Current (Pins 9, 10, 12, 19, 21, 22) Both Channels Enabled 239 287 mA
PARAMETER CONDITIONS MIN TYP MAX UNITS
Conversion Gain RF = 1750MHz
RF = 1950MHz
RF = 2150MHz
7.0
8.7
8.5
8.0
dB
dB
dB
Conversion Gain Flatness RF = 1950 ±30MHz, LO = 1760MHz, IF = 190 ±30MHz ±0.25 dB
Conversion Gain vs Temperature TC = –40ºC to 105ºC, RF = 1950MHz –0.006 dB/°C
Input 3rd Order Intercept RF = 1750MHz
RF = 1950MHz
RF = 2150MHz
24.0
26.9
26.2
26.2
dBm
dBm
dBm
SSB Noise Figure RF = 1750MHz
RF = 1950MHz
RF = 2150MHz
9.4
9.9
10.8
dB
dB
dB
PARAMETER CONDITIONS MIN TYP MAX UNITS
LO Input Frequency Range 1400 to 2100 MHz
RF Input Frequency Range Low Side LO
High Side LO
1600 to 2300
1300 to 1800
MHz
MHz
IF Output Frequency Range Requires External Matching 5 to 500 MHz
RF Input Return Loss ZO = 50Ω, 1300MHz to 2300MHz >12 dB
LO Input Return Loss ZO = 50Ω, 1400MHz to 2100MHz >12 dB
IF Output Impedance Differential at 190MHz 300Ω||2.3pF R||C
LO Input Power fLO = 1400MHz to 2100MHz –4 0 6 dBm
LO to RF Leakage fLO = 1400MHz to 2100MHz <–30 dBm
LO to IF Leakage fLO = 1400MHz to 2100MHz <–30 dBm
RF to LO Isolation fRF = 1300MHz to 2300MHz >45 dB
RF to IF Isolation fRF = 1300MHz to 2300MHz >30 dB
Channel-to-Channel Isolation fRF = 1750MHz to 2150MHz >47 dB
ac elecTrical characTerisTics
VCC = 3.3V, VCCIF = 3.3V, ENA = ENB = High, ISEL = Low, TC = 25°C,
PLO = 0dBm, PRF = –3dBm (∆f = 2MHz for two tone IIP3 tests), unless otherwise noted. Test circuit shown in Figure 1. (Notes 2, 3, 4)
Low Side LO Downmixer Application: ISEL = Low, RF = 1700MHz to 2300MHz, IF = 190MHz, fLO = fRF – fIF
LTC5591
4
5591f
PARAMETER CONDITIONS MIN TYP MAX UNITS
Conversion Gain RF = 1950MHz 7.2 dB
Input 3rd Order Intercept RF = 1950MHz 21.4 dBm
SSB Noise Figure RF = 1950MHz 10.3 dB
Input 1dB Compression RF = 1950MHz, VCCIF = 3.3V
RF = 1950MHz, VCCIF = 5V
10.7
11.7
dBm
dBm
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 LTC5591 is guaranteed functional over the case operating
temperature range of –40°C to 105°C. (θJC = 7°C/W)
Note 3: SSB Noise Figure measured 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, and no other RF signals applied.
Note 4: Channel A to channel B isolation is measured as the relative IF
output power of channel B to channel A, with the RF input signal applied to
channel A. The RF input of channel B is 50Ω terminated and both mixers
are enabled.
ac elecTrical characTerisTics
VCC = 3.3V, VCCIF = 3.3V, ENA = ENB = High, TC = 25°C, PLO = 0dBm,
PRF = –3dBm (∆f = 2MHz for two tone IIP3 tests), unless otherwise noted. Test circuit shown in Figure 1. (Notes 2, 3)
PARAMETER CONDITIONS MIN TYP MAX UNITS
SSB Noise Figure Under Blocking fRF =1950MHz, fLO = 1760MHz, fBLOCK = 2050MHz,
PBLOCK = 5dBm
PBLOCK = 10dBm
15.5
20.2
dB
dB
2RF-2LO Output Spurious Product
(fRF = fLO + fIF/2)
fRF = 1855MHz at –10dBm, fLO = 1760MHz,
fIF = 190MHz
–69 dBc
3RF-3LO Output Spurious Product
(fRF = fLO + fIF/3)
fRF = 1823.33MHz at –10dBm, fLO = 1760MHz,
fIF = 190MHz
–74 dBc
Input 1dB Compression fRF = 1950MHz, VCCIF = 3.3V
fRF = 1950MHz, VCCIF = 5V
10.7
13.9
dBm
dBm
Low Side LO Downmixer Application: ISEL = Low, RF = 1700MHz to 2300MHz, IF = 190MHz, fLO = fRF – fIF
Low Power Mode, Low Side LO Downmixer Application: ISEL = High, RF = 1700MHz to 2300MHz, IF = 190MHz, fLO = fRF – fIF
PARAMETER CONDITIONS MIN TYP MAX UNITS
Conversion Gain RF = 1450MHz
RF = 1600MHz
RF = 1750MHz
8.9
8.6
8.4
dB
dB
dB
Conversion Gain Flatness RF = 1600 ±30MHz, LO = 1790MHz, IF = 190 ±30MHz ±0.1 dB
Conversion Gain vs Temperature TC = –40ºC to 105ºC, RF = 1600MHz –0.007 dB/°C
Input 3rd Order Intercept RF = 1450MHz
RF = 1600MHz
RF = 1750MHz
25.0
24.6
24.3
dBm
dBm
dBm
SSB Noise Figure RF = 1450MHz
RF = 1600MHz
RF = 1750MHz
10.0
10.1
10.1
dB
dB
dB
SSB Noise Figure Under Blocking fRF = 1600MHz, fLO = 1790MHz, fBLOCK = 1500MHz,
PBLOCK = 5dBm
PBLOCK = 10dBm
16.4
21.2
dB
dB
2LO-2RF Output Spurious Product
(fRF = fLO – fIF/2)
fRF = 1695MHz at –10dBm, fLO = 1790MHz,
fIF = 190MHz
–64 dBc
3LO-3RF Output Spurious Product
(fRF = fLO – fIF/3)
fRF = 1726.67MHz at –10dBm, fLO = 1790MHz,
fIF = 190MHz
–75 dBc
Input 1dB Compression RF = 1600MHz, VCCIF = 3.3V
RF = 1600MHz, VCCIF = 5V
10.2
13.6
dBm
dBm
High Side LO Downmixer Application: ISEL = Low, RF = 1300MHz to 1800MHz, IF = 190MHz, fLO = fRF + fIF
LTC5591
5
5591f
Low Side LO
Typical ac perForMance characTerisTics
VCC = 3.3V, VCCIF = 3.3V, ENA = ENB = High, ISEL = Low, TC = 25°C, PLO = 0dBm, PRF = –3dBm (–3dBm/tone for two-tone IIP3 tests,
∆f = 2MHz), IF = 190MHz, unless otherwise noted. Test circuit shown in Figure 1.
SSB NF vs RF Frequency
Conversion Gain and IIP3 vs
RF Frequency
Channel Isolation vs
RF Frequency
1750MHz Conversion Gain,
IIP3 and NF vs LO Power
2150MHz Conversion Gain,
IIP3 and NF vs LO Power
1950MHz Conversion Gain,
IIP3 and NF vs LO Power
Conversion Gain, IIP3 and NF vs
Supply Voltage (Single Supply)
Conversion Gain, IIP3 and RF Input
P1dB vs Temperature
Conversion Gain, IIP3 and NF vs
IF Supply Voltage (Dual Supply)
RF FREQUENCY (GHz)
1.6
17
IIP3 (dBm)
GC (dB)
21
23
25
1.8 22.1
5591 G01
19
1.7 1.9 2.2 2.3 2.4
27
6
10
12
14
8
16
–40°C
25°C
85°C
105°C
IIP3
GC
RF FREQUENCY (GHz)
1.6
6
SSB NF (dB)
10
12
14
1.8 22.1
5591 G02
8
1.7 1.9 2.2 2.3 2.4
16 –40°C
25°C
85°C
105°C
LO INPUT POWER (dBm)
GC
–6
7
GC (dB), IIP3(dB)
SSB NF (dB)
15
19
23
–2 0 46
5591 G04
11
–4 2
27
13
17
21
9
25
0
8
12
16
4
20
6
10
14
2
18
–40°C
25°C
85°C
IIP3
NF
LO INPUT POWER (dBm)
–6
7
GC (dB), IIP3 (dB)
SSB NF (dB)
15
19
23
–2 0 46
5591 G05
11
–4 2
27
13
17
21
9
25
0
8
12
16
4
20
6
10
14
2
18
–40°C
25°C
85°C
IIP3
GC
NF
LO INPUT POWER (dBm)
–6
7
GC (dB), IIP3 (dB)
SSB NF (dB)
15
19
23
–2 0 46
5591 G06
11
–4 2
27
13
17
21
9
25
1
9
13
17
5
21
7
11
15
3
19
–40°C
25°C
85°C
IIP3
GC
NF
VCCIF SUPPLY VOLTAGE (V)
3
7
GC (dB), IIP3 (dBm)
SSB NF (dB)
15
19
23
3.6 4.2 4.53.9 5.1 5.4
5591 G08
11
3.3 4.8
27
13
17
21
9
25
2
10
14
18
6
22
8
12
16
4
20
–40°C
25°C
85°C
IIP3
GC
NF
RF = 1950MHz
VCC = 3.3V
CASE TEMPERATURE (°C)
–40
7
GC (dB), IIP3 (dBm), P1dB (dBm)
15
19
23
–10 20 355 65 80 95 110
5591 G09
11
–25 50
27
13
17
21
9
25 IIP3
GC
P1dB
RF = 1950MHz
VCCIF = 5V
VCCIF = 3.3V
RF FREQUENCY (GHz)
1.6
30
ISOLATION (dB)
40
45
50
1.8 22.1
5591 G03
35
1.7 1.9 2.2 2.42.3
55
–40°C
25°C
85°C
105°C
VCC, VCCIF SUPPLY VOLTAGE (V)
3
7
GC (dB), IIP3 (dB)
SSB NF (dB)
15
19
23
3.2 3.3 3.5 3.6
5591 G07
11
3.1 3.4
27
13
17
21
9
25
2
10
14
18
6
22
8
12
16
4
20
–40°C
25°C
85°C
IIP3
GC
NF
RF = 1950MHz
VCC = VCCIF
LTC5591
6
5591f
Low Side LO (continued)
Typical ac perForMance characTerisTics
VCC = 3.3V, VCCIF = 3.3V, ENA = ENB = High, ISEL = Low, TC = 25°C, PLO = 0dBm, PRF = –3dBm (–3dBm/tone for two-tone IIP3 tests,
∆f = 2MHz), IF = 190MHz, unless otherwise noted. Test circuit shown in Figure 1.
2-Tone IF Output Power, IM3
and IM5 vs RF Input Power
2 × 2 and 3 × 3 Spurs vs
LO Power
SSB Noise Figure vs RF
Blocker Power RF Isolation vs RF FrequencyLO Leakage vs LO Frequency
Conversion Gain Distribution SSB Noise Figure DistributionIIP3 Distribution
Single-Tone IF Output Power, 2 × 2
and 3 × 3 Spurs vs RF Input Power
RF INPUT POWER (dBm/TONE)
–12
–80
OUTPUT POWER/TONE (dBm)
–40
–20
0
–3 0–6 6
5591 G10
–60
–9 3
20
–50
–30
–10
–70
10 IFOUT
IM3
IM5
RF1 = 1949MHz
RF2 = 1951MHz
LO = 1760MHz
RF INPUT POWER (dBm)
–15 –12
–80
OUTPUT POWER (dBm)
–40
–20
0
–3 0–6 126 9
5591 G11
–60
–9 3
20
–50
–30
–10
–70
10 IFOUT
(RF = 1950MHz)
2RF-2LO
(RF = 1855MHz)
3RF-3LO
(RF = 1823.33MHz)
(LO = 1760MHz)
RF BLOCKER POWER (dBm)
–25
SSB NF (dB)
12
16
18
–15 –10 50 10
5591 G13
10
–20 –5
22
14
8
20
PLO = 3dBm
PLO = 0dBm
PLO = –3dBm
RF = 1950MHz
LO = 1760MHz
BLOCKER = 2050MHz
LO FREQUENCY (GHz)
1.2
–60
LO LEAKAGE (dBm)
–30
1.6 1.8 2.2
5591 G14
–50
1.4
LO-RF
2
–40
–20
LO-IF
RF FREQUENCY (GHz)
1.3
30
ISOLATION (dB)
45
1.7 1.9 2.1 2.5
5591 G15
35
1.5 2.3
40
55
50
RF-LO
RF-IF
LO INPUT POWER (dBm)
–6 –4
RELATIVE SPUR LEVEL (dBc)
–65
2 40
5591 G12
–75
–2 6
–70
–60
–80
RF = 1950MHz
PRF = –10dBm
LO = 1760MHz
2RF-2LO
(RF = 1855MHz)
3RF-3LO
(RF = 1823.33MHz)
IIP3 (dBm)
23.7 24 24.3 24.6 24.9 25.2 25.5 25.8 26.1 26.4 26.7
0
DISTRIBUTION (%)
20
5591 G17
10
5
15
25
–40°C
25°C
85°C
RF = 1950MHz
CONVERSION GAIN (dB)
7.8 8.0 8.2 8.4 8.6 8.8 9.0
0
DISTRIBUTION (%)
20
5591 G16
10
5
15
30
25
–40°C
25°C
85°C
RF = 1950MHz
SSB NOISE FIGURE (dB)
8.5 8.9 9.3 9.7 10.1 10.5 10.9 11.3 11.7
0
DISTRIBUTION (%)
35
5591 G18
25
20
10
5
15
30
40
–40°C
25°C
85°C
RF = 1950MHz
LTC5591
7
5591f
Typical ac perForMance characTerisTics
Low Power Mode, Low Side LO
VCC = 3.3V, VCCIF = 3.3V, ENA = ENB = High, ISEL = High, TC = 25°C, PLO = 0dBm, PRF = –3dBm (–3dBm/tone for two-tone IIP3 tests,
∆f = 2MHz), IF = 190MHz, unless otherwise noted. Test circuit shown in Figure 1.
SSB NF vs RF Frequency
Conversion Gain and IIP3 vs
RF Frequency
Channel Isolation vs
RF Frequency
1750MHz Conversion Gain,
IIP3 and NF vs LO Power
2150MHz Conversion Gain,
IIP3 and NF vs LO Power
1950MHz Conversion Gain,
IIP3 and NF vs LO Power
Conversion Gain, IIP3 and
RF Input P1dB vs Temperature
Conversion Gain, IIP3 and NF vs
IF Supply Voltage (Dual Supply)
Conversion Gain, IIP3 and NF vs
Supply Voltage (Single Supply)
RF FREQUENCY (GHz)
1.6
13
IIP3 (dBm)
GC (dB)
17
19
21
1.9 2 2.1 2.2 2.3 2.4
5591 G19
15
1.7 1.8
23
5
9
11
13
7
15
–40°C
25°C
85°C
105°C
IIP3
GC
RF FREQUENCY (GHz)
1.6
6
SSB NF (dB)
10
12
14
1.9 2 2.1 2.2 2.42.3
5591 G20
8
1.7 1.8
16
–40°C
25°C
85°C
105°C
VCC, VCCIF SUPPLY VOLTAGE (V)
3
GC (dB), IIP3 (dBm)
SSB NF (dB)
12
16
20
3.2 3.3 3.5 3.6
5591 G25
8
3.1 3.4
24
10
14
18
6
22
8
12
16
4
20
6
10
14
2
18
–40°C
25°C
85°C
IIP3
GC
NF
RF = 1950MHz
VCC = VCCIF
VCCIF SUPPLY VOLTAGE (V)
3
GC (dB), IIP3 (dBm)
SSB NF (dB)
12
16
20
3.6 3.9 4.8 5.1 5.4
5591 G26
8
3.3 4.2 4.5
24
10
14
18
6
22
8
12
16
4
20
6
10
14
2
18
–40°C
25°C
85°C
IIP3
GC
NF
RF = 1950MHz
VCC = 3.3V
CASE TEMPERATURE (°C)
–40 –25 –10 5
GC (dB), IIP3 (dBm) P1dB (dBm)
14
18
22
3520 80 95 110
5591 G27
10
50 65
26
12
16
20
6
8
24
VCCIF = 5V
VCCIF = 3.3V
IIP3
GC
RF = 1950MHz
P1dB
RF FREQUENCY (GHz)
1.6
30
ISOLATION (dB)
40
45
50
1.9 2 2.1 2.2 2.3
2.4
5591 G21
35
1.7 1.8
55
–40°C
25°C
85°C
105°C
LO INPUT POWER (dBm)
–6
4
GC (dB), IIP3 (dBm)
SSB NF (dB)
12
16
20
–2 0 46
5591 G22
8
–4 2
24
10
14
18
6
22
0
8
12
16
4
20
6
10
14
2
18
–40°C
25°C
85°C
IIP3
GC
NF
LO INPUT POWER (dBm)
–6
4
GC (dB), IIP3 (dBm)
SSB NF (dB)
12
16
20
–2 0 46
5591 G23
8
–4 2
24
10
14
18
6
22
0
8
12
16
4
20
6
10
14
2
18
–40°C
25°C
85°C
IIP3
GC
NF
LO INPUT POWER (dBm)
–6
4
GC (dB), IIP3 (dBm)
SSB NF (dB)
12
16
20
–2 0 46
5591 G24
8
–4 2
24
10
14
18
6
22
0
8
12
16
4
20
6
10
14
2
18
–40°C
25°C
85°C
IIP3
GC
NF
LTC5591
8
5591f
Typical ac perForMance characTerisTics
High Side LO
VCC = 3.3V, VCCIF = 3.3V, ENA = ENB = High, ISEL = Low, TC = 25°C, PLO = 0dBm, PRF = –3dBm (–3dBm/tone for two-tone IIP3 tests,
∆f = 2MHz), IF = 190MHz, unless otherwise noted. Test circuit shown in Figure 1.
SSB NF vs RF Frequency
Conversion Gain and IIP3 vs
RF Frequency
2-Tone IF Output Power, IM3
and IM5 vs RF Input Power
1450MHz Conversion Gain,
IIP3 and NF vs LO Power
1750MHz Conversion Gain,
IIP3 and NF vs LO Power
1600MHz Conversion Gain,
IIP3 and NF vs LO Power
Conversion Gain, IIP3 and NF vs
Supply Voltage (Single Supply)
Single-Tone IF Output Power, 2 × 2
and 3 × 3 Spurs vs RF Input Power
Conversion Gain, IIP3 and RF
Input P1dB vs Temperature
RF FREQUENCY (GHz)
1.25
6
SSB NF (dB)
10
12
14
1.55 1.65
5591 G29
8
1.35 1.45 1.75 1.85
16 –40°C
25°C
85°C
105°C
RF INPUT POWER (dBm/TONE)
–12
–90
–80
OUTPUT POWER TONE (dBm)
–50
–40
–30
–20
–10
0
–3 0
5591 G30
–70
–60
–9 –6 03
20
10
RF1 = 1599MHz
RF2 = 1601MHz
LO = 1790MHz
IFOUT
IM5
IM3
VCC, VCCIF SUPPLY VOLTAGE (V)
3
GC (dB), IIP3 (dBm)
SSB NF (dB)
13
17
21
3.2 3.3 3.5 3.6
5591 G34
9
3.1 3.4
25
11
15
19
7
23
8
12
16
4
20
6
10
14
2
18
–40°C
25°C
85°C
IIP3
GC
NF
RF = 1600MHz
VCC = VCCIF
RF INPUT POWER (dBm)
–12 –9 –6 –3
OUTPUT POWER (dBm)
–40
–20
0
30 12 15
5591 G36
–60
6 9
20
–50
–30
–10
–80
–70
10
3LO-3RF
(RF = 1726.67MHz)
IFOUT
(RF = 1600MHz)
(LO = 1790MHz)
2LO-2RF
(RF = 1695MHz)
RF FREQUENCY (GHz)
1.25
16
IIP3 (dBm)
GC (dB)
20
22
24
1.55 1.65
5591 G28
18
1.35 1.45 1.75 1.85
26
6
10
12
14
8
16
–40°C
25°C
85°C
105°C
IIP3
GC
CASE TEMPERATURE (°C)
–40 –25 –10 5
GC (dB), IIP3 (dBm), P1dB (dBm)
14
18
22
3520 80 95 110
5591 G35
8
10
50 65
26
12
16
20
6
24
VCCIF = 5V
VCCIF = 3.3V
IIP3
GC
RF = 1600MHz
P1dB
LO INPUT POWER (dBm)
–6
6
GC (dB), IIP3 (dBm)
SSB NF (dB)
14
18
22
–2 0 46
5591 G31
10
–4 2
26
12
16
20
8
24
0
8
12
16
4
20
6
10
14
2
18
–40°C
25°C
85°C
IIP3
GC
NF
LO INPUT POWER (dBm)
–6
6
GC (dB), IIP3 (dBm)
SSB NF (dB)
14
18
22
–2 0 46
5591 G32
10
–4 2
26
12
16
20
8
24
0
8
12
16
4
20
6
10
14
2
18
–40°C
25°C
85°C
IIP3
GC
NF
LO INPUT POWER (dBm)
–6
6
GC (dB), IIP3 (dBm)
SSB NF (dB)
14
18
22
–2 0 46
5591 G33
10
–4 2
26
12
16
20
8
24
0
8
12
16
4
20
6
10
14
2
18
–40°C
25°C
85°C
IIP3
GC
NF
LTC5591
9
5591f
Typical Dc perForMance characTerisTics
VCC Supply Current vs Supply
Voltage (Mixer and LO Amplifier)
VCCIF Supply Current vs Supply
Voltage (IF Amplifier)
Total Supply Current vs
Temperature (VCC + VCCIF)
ENA = ENB = High, test circuit shown in Figure 1.
VCC Supply Current vs Supply
Voltage (Mixer and LO Amplifier)
VCCIF Supply Current vs Supply
Voltage (IF Amplifier)
Total Supply Current vs
Temperature (VCC + VCCIF)
ISEL = Low
ISEL = High
VCC SUPPLY VOLTAGE (V)
33.1 3.2
SUPPLY CURRENT (mA)
184
188
192
3.43.3
5591 G37
180
3.5 3.6
182
186
190
176
178
–40°C
25°C
85°C
105°C
VCCIF SUPPLY VOLTAGE (V)
33.3 3.6
SUPPLY CURRENT (mA)
200
260
4.23.9
5591 G38
160
4.5 4.8 5.1 5.4
180
220
240
140
–40°C
25°C
85°C
105°C
CASE TEMPERATURE (°C)
–40 –25 –10
SUPPLY CURRENT (mA)
400
460
205
5591 G39
360
35 50 11065 9580
380
420
440
340
VCC = 3.3V, VCCIF = 5V
(DUAL SUPPLY)
VCC = 3.3V, VCCIF = 3.3V
(SINGLE SUPPLY)
VCCIF SUPPLY VOLTAGE (V)
33.3
SUPPLY CURRENT (mA)
130
3.9 4.23.6
5591 G41
110
4.5 5.14.8 5.4
150
90
–40°C
25°C
85°C
105°C
CASE TEMPERATURE (°C)
–20–40
SUPPLY CURRENT (mA)
260
20 400
5591 G42
240
220
60 10080
280
200
VCC = VCCIF = 3.3V
(SINGLE SUPPLY)
VCC = 3.3V, VCCIF = 5V
(DUAL SUPPLY)
VCC SUPPLY VOLTAGE (V)
33.1
SUPPLY CURRENT (mA)
120
124
3.33.2
5591 G40
116
3.4 3.5 3.6
118
122
114
–40°C
25°C
85°C
105°C
LTC5591
10
5591f
pin FuncTions
RFA, RFB (Pins 1, 6): Single-Ended RF Inputs for Chan-
nels A and B. These pins are internally connected to the
primary sides of the RF input transformers, which have
low DC resistance to ground. Series DC-blocking capaci-
tors should be used to avoid damage to the integrated
transformer when DC voltage is present at the RF inputs.
The RF inputs are impedance matched when the LO input
is driven with a 0±6dBm source between 1.4GHz and
2.1GHz and the channels are enabled.
CTA, CTB (Pins 2, 5): RF Transformer Secondary Center-
Tap on Channels A and B. These pins may require bypass
capacitors to ground to optimize IIP3 performance. Each
pin has an internally generated bias voltage of 1.2V and
must be DC-isolated from ground and VCC.
GND (Pins 3, 4, 7, 13, 15, 24, Exposed Pad Pin 25):
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.
IFGNDB, IFGNDA (Pins 8, 23): DC Ground Returns for the
IF Amplifiers. These pins must be connected to ground to
complete the DC current paths for the IF amplifiers. Chip
inductors may be used to tune LO-IF and RF-IF leakage.
Typical DC current is 100mA for each pin.
IFB+, IFB–, IFA–, IFA+ (Pins 9, 10, 21, 22): Open-Collec-
tor Differential Outputs for the IF Amplifiers of Channels
B and A. These pins must be connected to a DC supply
through impedance matching inductors, or transformer
center-taps. Typical DC current consumption is 50mA
into each pin.
IFBB, IFBA (Pins 11, 20): Bias Adjust Pins for the IF
Amplifiers. These pins allow independent adjustment
of the internal IF buffer currents for channels B and A,
respectively. The typical DC voltage on these pins is 2.2V.
If not used, these pins must be DC isolated from ground
and VCC.
VCCB and VCCA (Pins 12, 19): Power Supply Pins for the
LO Buffers and Bias Circuits. These pins must be con-
nected to a regulated 3.3V supply with bypass capacitors
located close to the pins. Typical current consumption is
91mA per pin.
ENB, ENA (Pins 14, 17): Enable Pins. These pins allow
Channels B and A, respectively, to be independently en-
abled. An applied voltage of greater than 2.5V activates
the associated channel while a voltage of less than 0.3V
disables the channel. Typical input current is less than
10μA. These pins must not be allowed to float.
LO (Pin 16): Single-Ended Local Oscillator Input. This
pin is internally connected to the primary side of the LO
input transformer and has a low DC resistance to ground.
Series DC-blocking capacitors should be used to avoid
damage to the integrated transformer when DC voltage
is present at the LO input. The LO input is internally
matched to 50Ω for all states of ENA and ENB.
ISEL (Pin 18): Low Current Select Pin. When this pin is
pulled low (<0.3V), both mixer channels are biased at the
normal current level for best RF performance. When greater
than 2.5V is applied, both channels operate at reduced
current, which provides reasonable performance at lower
power consumption. This pin must not be allowed to float.
LTC5591
11
5591f
block DiagraM
5591 BD
BIAS
BIAS
GND
ENA
ISEL
LO
VCCB
IFBB
VCCA
IFBA
IFB–
IFB+
IFA–
IFA+
IFGNDB
IFGNDA
GND
RFB
LO
AMP
LO
AMP
ENB
GND
IF
AMP
11109 12
14
13
GND 15
16
17
18
6
87
CTB
5
GND
4
GND
3
CTA
2
RFA
1
IF
AMP
22 21 20 192324
LTC5591
12
5591f
TesT circuiT
L1, L2 vs IF FREQUENCIES
IF (MHz) L1, L2 (nH)
140 270
190 150
240 100
300 56
380 33
REF DES VALUE SIZE VENDOR
C1A, C1B,
C8A, C8B
2.7pF 0402 AVX
C2 4.7pF 0402 AVX
C3A, C3B
C5A, C5B
22pF 0402 AVX
C4, C6 1µF 0603 AVX
C7A, C7B 1000pF 0402 AVX
L1, L2 150nH 0603 Coilcraft
T1A, T1B TC1-1W-7ALN+ Mini-Circuits
Figure 1. Standard Test Circuit Schematic (190MHz IF)
RF
GND
GND
BIAS
DC1710A
EVALUATION BOARD
STACK-UP
(NELCO N4000-13)
0.015”
0.015”
0.062”
4:1
T1A
IFA
50Ω
C7A
L2AL1A
C5AC6
C3A C4
1
192021222324
121110987
LO
50Ω
17
18
16
15
14
C2
5
6 13
4
3
RFA
50Ω
VCCIF
3.3V TO 5V
C1A
RFB
50Ω
C1B
2
IFGNDAGND IFA+IFA–IFBA
LO
GND
GND
ISEL
ENB
ENA
VCCA
IFGNDBGND IFB+IFB–IFBB VCCB
RFA
CTA
GND
GND
CTB
RFB
5591 TC01
4:1
T1B
IFB
50Ω
C5B
C3B
C8A
C8B
C7B
L1BL2B
ISEL
(0V/3.3V)
VCC
3.3V
ENA
(0V/3.3V)
ENB
(0V/3.3V)
LTC5591
25
GND
LTC5591
13
5591f
Introduction
The LTC5591 consists of two identical mixer channels
driven by a common LO input signal. Each high linearity
mixer consists of a passive double-balanced mixer core,
IF buffer amplifier, LO buffer amplifier and bias/enable
circuits. See the Pin Functions and Block Diagram sections
for a description of each pin. Each of the mixers can be
shutdown independently to reduce power consumption and
low current mode can be selected that allows a trade-off
between performance and power consumption. The RF and
LO inputs are single-ended and are internally matched to
50Ω. Low side or high side LO injection can be used. The
IF outputs are differential. 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.
applicaTions inForMaTion
Figure 2. Evaluation Board Layout
if the source has DC voltage present, since the primary
side of the RF transformer is internally DC-grounded. The
DC resistance of the primary is approximately 3.6Ω.
The secondary winding of the RF transformer is inter-
nally connected to the channel A passive mixer core. The
center-tap of the transformer secondary is connected to
Pin 2 (CTA) to allow the connection of bypass capacitor,
C8A. The value of C8A can be adjusted to improve the
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.
RF Inputs
The RF inputs of channels A and B are identical. The RF
input of channel A, shown in Figure 3, is connected to the
primary winding of an integrated transformer. A 50Ω match
is realized when a series external capacitor, C1A, is con-
nected to the RF input. C1A is also needed for DC blocking
Figure 3. Channel A RF Input Schematic
Figure 4. Channel-to-Channel Isolation vs C8 Values
RF FREQUENCY (MHz)
1250
30
CHANNEL ISOLATION (dB)
40
45
50
1650 2050 2250
5591 F04
35
1450 1850 2450
55
C8 OPEN
C8 = 2.2pF
C8 = 2.7pF
C8 = 3.3pF
5591 F02
LTC5591
C1A
C8A
RFA
CTA
RFA
TO CHANNEL A
MIXER
1
2
5591 F03
LTC5591
14
5591f
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 = 2.2pF. The measured
input return loss is shown in Figure 4 for LO frequencies
of 1.4GHz, 1.75GHz and 2GHz. 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 1.3GHz to 2.3GHz RF band.
applicaTions inForMaTion
Figure 6. LO Input Schematic
LO Input
The LO input, shown in Figure 6, is connected to the
primary winding of an integrated transformer. A 50Ω
impedance match is realized at the LO port by adding
an 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.
The secondary of the transformer drives a pair of high
speed limiting differential amplifiers for channels A and B.
The LTC5591’s LO amplifiers are optimized for the 1.4GHz
to 2.1GHz LO frequency range; however, LO frequencies
outside this frequency range may be used with degraded
performance.
The LO port is always 50Ω matched when VCC is applied,
even when one or both of the channels is disabled. This
helps to reduce frequency pulling of the LO source when
LO
TO
MIXER B
LTC5591
ISEL
5591 F06
18
LO 16
17
ENA
ENB
C2
14
BIAS
BIAS
TO
MIXER A
Figure 5. RF Port Return Loss
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 1.75GHz.
Table 1. RF Input Impedance and S11
(at Pin 1, No External Matching, fLO = 1.75GHz)
FREQUENCY
(GHz)
RF INPUT
IMPEDANCE
S11
MAG ANGLE
1.0 25.3 + j34.6 0.51 100.8
1.2 33.7 + j38.7 0.46 88.1
1.4 43.8 + j38.6 0.39 76.8
1.6 56.0 + j33.5 0.31 62.3
1.8 48.1 + j9.1 0.09 96.4
2.0 38.5 + j21.4 0.27 104.6
2.2 40.1 + j28.3 0.32 91.8
2.4 44.0 + j34.7 0.35 79.6
2.6 52.1 + j40.7 0.37 65.3
2.8 64.1 + j44.1 0.38 51.2
3.0 78.8 + j42.0 0.38 37.5
RF FREQUENCY (GHz)
1
60
RF PORT RETURN LOSS (dB)
30
40
20
10
1.4 22.2 2.4 2.6 2.81.8
5591 F05
50
1.2 1.6 3
0
LO = 1.4GHz
LO = 1.75GHz
LO = 2GHz
LTC5591
15
5591f
Figure 7. LO Input Return Loss
the mixer is switched between different operating states.
Figure 7 illustrates the LO port return loss for the different
operating modes.
applicaTions inForMaTion
return pin (IFGNDA), and a pin for adjusting the internal
bias (IFBA). The IF outputs must be biased at the sup-
ply voltage (VCCIFA), which is applied through matching
inductors L1A and L2A. Alternatively, the IF outputs can
be biased through the center tap of a transformer (T1A).
The common node of L1A and L2A can be connected to
the center tap of the transformer. Each IF output pin draws
approximately 50mA of DC supply current (100mA total).
An external load resistor, R2A, can be used to improve
impedance matching if desired.
IFGNDA (Pin 23) must be grounded or the amplifier will
not draw DC current. Inductor L3A may improve LO-IF
and RF-IF leakage performance in some applications, but
is otherwise not necessary. Inductors should have small
resistance for DC. High DC resistance in L3A will reduce
the IF amplifier supply current, which will degrade RF
performance.
Figure 8. IF Amplifier Schematic with Bandpass Match
4:1
T1A IFA
C7A
L2AL1A
C5A
R2A
L3A (OR SHORT)
VCCIFA
20212223
IF
AMP
BIAS
100mA
4mA
IFBA
VCCA
LTC5591
IGNDA
IFA–
IFA+
R1A
(OPTION TO
REDUCE
DC POWER)
5591 F08
The nominal LO input level is 0dBm, though the limiting
amplifiers will deliver excellent performance over a ±6dBm
input power range. Table 2 lists the LO input impedance
and input reflection coefficient versus frequency.
Table 2. LO Input Impedance vs Frequency
(at Pin 16, No External Matching, ENA = ENB = High)
FREQUENCY
(GHz)
INPUT
IMPEDANCE
S11
MAG ANGLE
1.0 39.4 + j46.4 0.47 75.5
1.2 55.3 + j40.8 0.36 61.4
1.4 61.9 + j26.8 0.25 52.6
1.6 56.5 + j16.1 0.16 59.5
1.8 47.6 + j14.0 0.14 91.6
2.0 41.6 + j18.0 0.21 103.9
2.2 38.4 + j23.5 0.29 101.5
2.4 37.1 + j30.7 0.36 93.3
2.6 38.4 + j38.3 0.42 83.3
2.8 42.0 + j47.6 0.47 72.2
3.0 48.6 + j56.1 0.49 61.8
IF Outputs
The IF amplifiers in channels A and B are identical. The IF
amplifier for channel A, shown in Figure 8, has differen-
tial open collector outputs (IFA+ and IFA–), a DC ground
LO FREQUENCY (GHz)
1
LO1 PORT RETURN LOSS (dB)
1.4 22.2 2.4 2.6 2.81.8
5591 F07
1.2 1.6
0.8
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
BOTH CHANNELS ON ONE
CHANNEL ON
BOTH CHANNELS OFF
For optimum single-ended performance, the differential
IF output must be combined through an external IF
transformer or a discrete IF balun circuit. The evaluation
board (see Figures 1 and 2) uses a 4:1 IF transformer for
impedance transformation and differential to single-ended
conversion. It is also possible to eliminate the IF transformer
and drive differential filters or amplifiers directly.
LTC5591
16
5591f
At IF frequencies, the IF output impedance can be modeled
as 300Ω in parallel with 2.3pF. The equivalent small-signal
model, including bondwire inductance, is shown in Figure 9.
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 ef-
fects of IC and package parasitics.
applicaTions inForMaTion
Figure 10. IF Output Return Loss with Bandpass Matching
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.
Figure 11. IF Output with Lowpass Matching
Figure 9. IF Output Small-Signal Model
22 21
IFA+IFA–
0.9nH0.9nH
RIF
CIF
LTC5591
5591 F09
Bandpass IF Matching
The bandpass IF matching configuration, shown in Figures
1 and 8, is best suited for IF frequencies in the 90MHz to
500MHz range. Resistor R2A may be used to reduce the IF
output resistance for greater bandwidth and inductors L1A
and L2A resonate with the internal IF output capacitance
at the desired IF frequency. The value of L1A, L2A can be
estimated as follows:
L1A =L2A =1
2πfIF
( )
2•2•CIF
where CIF is the internal IF capacitance (listed in Table 3).
Table 3. IF Output Impedance vs Frequency
FREQUENCY (MHz)
DIFFERENTIAL OUTPUT
IMPEDANCE (RIF || XIF (CIF))
90 321 || –j769 (2.3pF)
140 307 || –j494 (2.3pF)
190 300 || –j364 (2.3pF)
240 292 || –j286 (2.3pF)
300 285 || –j225 (2.4pF)
380 276 || –j177 (2.4pF)
500 264 || –j122 (2.6pF)
Lowpass IF Matching
For IF frequencies below 90MHz, the inductance values
become unreasonably high and the lowpass topology
shown in Figure 11 is preferred. This topology also can
provide improved RF to IF and LO to IF isolation. VCCIFA
is supplied through the center tap of the 4:1 transformer.
A lowpass impedance transformation is realized by shunt
elements R2A and C9A (in parallel with the internal RIF and
CIF), and series inductors L1A and L2A. Resistor R2A is
used to reduce the IF output resistance for greater band-
width, or it can be deleted for the highest conversion gain.
The final impedance transformation to 50Ω is realized by
transformer T1A. The measured IF output return loss for
IF FREQUENCY (MHz)
100
IF PORT RETURN LOSS (dB)
150 250 300 350 400 450
5591 F10
200
50
0
5
10
15
20
30
25
L1, L2 = 270nH
L1, L2 = 150nH
L1, L2 = 100nH
L1, L2 = 56nH
4:1
T1A IFA
50Ω
VCCIFA
3.1 TO 5.3V
C5A
2122 IFA–
IFA+
C6
C9A
R2A
L1A L2A
LTC5591
5591 F11
LTC5591
17
5591f
Figure 12. IF Output Return Loss with Lowpass Matching
applicaTions inForMaTion
lowpass IF matching with R2A and C9A open is plotted
in Figure 12. The LTC5591 demo board (see Figure 2) has
been laid out to accommodate this matching topology with
only minor modifications.
Table 4. Performance Comparison with VCCIF = 3.3V and 5V
(RF = 1950MHz, Low Side LO, IF = 190MHz, ENA = ENB = High)
VCCIF
(V)
R2A
(Ω)
ICCIF
(mA)
GC
(dB)
P1dB
(dBm)
IIP3
(dBm)
NF
(dB)
3.3 Open 200 8.5 10.7 26.2 9.9
1k 200 7.4 11.5 26.5 9.9
5 Open 207 8.4 13.9 26.7 10.1
The IFBA pin (Pin 20) is available for reducing the DC
current consumption of the IF amplifier, at the expense of
IIP3. The nominal DC voltage at Pin 20 is 2.1V, and 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 approxi-
mately 100mA. If resistor R1A is connected to Pin 20 as
shown in Figure 8, a portion of the reference current can
be shunted to ground, resulting in reduced IF amplifier
current. For example, R1A = 470Ω will shunt away 1.4mA
from Pin 20 and the IF amplifier current will be reduced
by 35% to approximately 65mA. Table 5 summarizes RF
performance versus total IF amplifier current when both
channels are enabled.
Table 5. Mixer Performance with Reduced IF Amplifier Current
RF = 1950MHz, Low Side LO, IF = 190MHz, VCC = VCCIF = 3.3V
R1A, R1B
ICCIF
(mA)
GC
(dB)
IIP3
(dBm)
P1dB
(dBm)
NF
(dB)
Open 200 8.5 26.2 10.7 9.9
3.3kΩ 176 8.4 25.7 10.8 9.9
1.0kΩ 151 8.1 24.7 10.9 9.9
470Ω 130 7.9 23.7 10.9 9.9
RF = 1600MHz, High Side LO, IF = 190MHz, VCC = VCCIF = 3.3V
R1A, R1B
ICCIF
(mA)
GC
(dB)
IIP3
(dBm)
P1dB
(dBm)
NF
(dB)
Open 200 8.6 24.6 10.2 10.2
3.3kΩ 176 8.4 24.3 10.4 10.3
1.0kΩ 151 8.1 23.5 10.6 10.3
470Ω 130 7.9 22.7 10.5 10.3
IF Amplifier Bias
The IF amplifier delivers excellent performance with VCCIF
= 3.3V, which allows a single supply to be used for VCC
and VCCIF. At VCCIF = 3.3V, the RF input P1dB of the mixer
is limited by the output voltage swing. For higher P1dB,
in this case, resistor R2A (Figure 7) can be used to reduce
the output impedance and thus the voltage swing, thus
improving P1dB. The trade-off for improved P1dB will be
lower conversion gain.
With VCCIF increased to 5V the P1dB increases by over
3dB, at the expense of higher power consumption. Mixer
P1dB performance at 1950MHz is tabulated in Table 4 for
VCCIF values of 3.3V and 5V. For the highest conversion
gain, high-Q wire-wound chip inductors are recommended
for L1A and L2A, especially when using VCCIF = 3.3V. Low
cost multilayer chip inductors may be substituted, with a
slight reduction in conversion gain.
IF FREQUENCY (MHz)
IF PORT RETURN LOSS (dB)
90 170 210 250
5591 F12
130
50
0
5
10
15
20
25
30
35
L1, L2 = 100nH
L1, L2 = 180nH
L1, L2 = 56nH
LTC5591
18
5591f
Figure 14. ENA Interface Schematic
Low Current Mode
Both mixer channels can be set to low current mode using
the ISEL pin. This allows flexibility to choose a reduced
current mode of operation when lower RF performance
is acceptable. Figure 13 shows a simplified schematic of
the ISEL pin interface. When ISEL is set low (<0.3V), both
channels operate at nominal DC current. When ISEL is set
high (>2.5V), the DC currents in both channels are reduced,
thus reducing power consumption. The performance in
low power mode and normal power mode are compared
in Table 6.
applicaTions inForMaTion
LTC5591
17
ENA 500Ω
VCCA
5591 F14
19
CLAMP
Figure 13. ISEL Interface Schematic
LTC5591
18
ISEL
VCCB
500Ω
VCCA
5591 F13
19
BIAS A
BIAS B
Table 6. Performance Comparison Between Different Power Modes
RF = 1950MHz, Low Side LO, IF = 190MHz, ENA = ENB = High
ISEL
ITOTAL
(mA)
GC
(dB)
IIP3
(dBm)
P1dB
(dBm)
NF
(dB)
Low 382 8.5 26.2 10.7 9.9
High 239 7.2 21.4 10.7 10.3
Enable Interface
Figure 14 shows a simplified schematic of the ENA pin
interface (ENB is identical). To enable channel A, the ENA
voltage must be greater than 2.5V. If the enable function
is not required, the enable pin can be connected directly
to VCC. The voltage at the enable 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.
The Enable pins must be pulled high or low. If left float-
ing, the on/off state of the IC will be indeterminate. If a
three-state condition can exist at the enable pins, then a
pull-up or pull-down resistor must be used.
Supply Voltage Ramping
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 volt-
age transient that exceeds the maximum rating. A supply
voltage ramp time of greater than 1ms is recommended.
Spurious Output Levels
Mixer spurious output levels versus harmonics of the
RF and LO are tabulated in Table 7. The spur levels were
measured on a standard evalution board using the test
circuit shown in Figure 1. The spur frequencies can be
calculated using the following equation:
fSPUR = (M • fRF)–(N • fLO)
Table 7. IF Output Spur Levels (dBc)
RF = 1950MHz, PRF = –3dBm, PLO = 0dBm, PIF 190MHz, Low Side LO,
VCC = 3.3V, VCCIF = 3.3V, ENA = ENB = High, ISEL = Low, TC = 25°C
N
M
0123456789
0–41 –54 –64 –84 –66 –74 –75 –81 –84
1–49 0 –56 –42 –68 –77 –75 –70 * –92
2–82 –83 –70 –77 * * * * * *
3* –88 * –71 ******
4**********
5**********
6*********
7* * * * * * –84 *
*Less than –100dBc
LTC5591
19
5591f
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
package DescripTion
UH Package
24-Lead Plastic QFN (5mm × 5mm)
(Reference LTC DWG # 05-08-1747 Rev A)
5.00 ± 0.10
5.00 ± 0.10
NOTE:
1. DRAWING IS NOT A JEDEC PACKAGE OUTLINE
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 0.20mm 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
PIN 1
TOP MARK
(NOTE 6)
0.55 ± 0.10
23
1
2
24
BOTTOM VIEW—EXPOSED PAD
3.25 REF
3.20 ± 0.10
3.20 ± 0.10
0.75 ± 0.05 R = 0.150
TYP
0.30 ± 0.05
(UH24) QFN 0708 REV A
0.65 BSC
0.200 REF
0.00 – 0.05
0.75 ±0.05
3.25 REF
3.90 ±0.05
5.40 ±0.05
0.30 ± 0.05
PACKAGE OUTLINE
0.65 BSC
RECOMMENDED SOLDER PAD LAYOUT
APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED
PIN 1 NOTCH
R = 0.30 TYP
OR 0.35 × 45°
CHAMFER
R = 0.05
TYP
3.20 ± 0.05
3.20 ± 0.05
UH Package
24-Lead Plastic QFN (5mm × 5mm)
(Reference LTC DWG # 05-08-1747 Rev A)
LTC5591
20
5591f
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
LINEAR TECHNOLOGY CORPORATION 2011
LT 0311 • PRINTED IN USA
relaTeD parTs
Typical applicaTion
PART NUMBER DESCRIPTION COMMENTS
Infrastructure
LT5527 400MHz to 3.7GHz, 5V Downconverting Mixer 2.3dB Gain, 23.5dBm IIP3 and 12.5dB NF at 1900MHz, 5V/78mA Supply
LT5557 400MHz to 3.8GHz, 3.3V Downconverting Mixer 2.9dB Gain, 24.7dBm IIP3 and 11.7dB NF at 1950MHz, 3.3V/82mA Supply
LTC6416 2GHz 16-Bit ADC Buffer 40.25dBm OIP3 to 300MHz, Programmable Fast Recovery Output Clamping
LTC6412 31dB Linear Analog VGA 35dBm OIP3 at 240MHz, Continuous Gain Range –14dB to 17dB
LTC5540/LTC5541/
LTC5542/LTC5543
600MHz to 4GHz Downconverting Mixer Family 8dB Gain, >25dBm IIP3, 10dB NF, 3.3V/200mA Supply
LT5554 Ultralow Distort IF Digital VGA 48dBm OIP3 at 200MHz, 2dB to 18dB Gain Range, 0.125dB Gain Steps
LT5578 400MHz to 2.7GHz Upconverting Mixer 27dBm OIP3 at 900MHz, 24.2dBm at 1.95GHz, Integrated RF Transformer
LT5579 1.5GHz to 3.8GHz Upconverting Mixer 27.3dBm OIP3 at 2.14GHz, NF = 9.9dB, 3.3V Supply, Single-Ended LO and RF Ports
RF Power Detectors
LT5534 50MHz to 3GHz Log RF Power Detector with
60dB Dynamic Range
±1dB Output Variation over Temperature, 38ns Response Time, Log Linear
Response
LT5581 6GHz Low Power RMS Detector 40dB Dynamic Range, ±1dB Accuracy Over Temperature, 1.5mA Supply Current
LTC5583 Dual 6GHz RMS Power Detector Measures
VSWR
40MHz to 6GHz, Up to 60dB Dynamic Range, >40dB Channel-to-Channel
Isolation, Difference Output for VSWR Measurement
ADCs
LTC2285 14-Bit, 125Msps Dual ADC 72.4dB SNR, >88dB SFDR, 790mW Power Consumption
LTC2185 16-Bit, 125Msps Dual ADC Ultralow Power 76.8dB SNR, 185mW/Channel Power Consumption
LTC2242-12 12-Bit, 250Msps ADC 65.4dB SNR, 78dB SFDR, 740mW Power Consumption
Lowpass IF Matching, Low Side LO, VCC = 3.3V, VCCIF = 3.3V, ENA = ENB = High, ISEL = Low, TC = 25°C,
PLO = 0dBm, PRF = –3dBm (–3dBm/Tone for Two-Tone IIP3 Tests, ∆f = 2MHz), IF = 190MHz
Conversion Gain, IIP3 and SSB NF
vs RF Frequency
IFA
50Ω
4:1
T1A
56nH 56nH
22pF
1µF
22pF 1µF
LTC5591
CHANNEL A
CHANNEL B NOT SHOWN
1
192021222324
LO
50Ω
17
18
16
15
4.7pF
4
3
RFA
50Ω
VCCIF
3.3V TO 5V
VCC
3.3V
TO
CHANNEL B
TO
CHANNEL B
2.7pF
2
IFGNDAGND IFA+IFA–IFBA
LO
GND
ISEL
ENA
VCCA
RFA
CTA
GND
GND
5591 TA02a
ISEL
ENA
2.7pF
RF FREQUENCY (GHz)
1.7
GC (dB), IIP3 (dBm)
SSB NF (dB)
1.8 2.0 2.1 2.2 2.3 2.4
5591 TA02b
1.9
1.6
28
26
24
20
18
22
16
12
10
8
14
6
16
15
14
12
11
13
10
8
7
6
9
5
IIP3
NF
GC
