LT5579
1
5579fa
Typical applicaTion
FeaTures
applicaTions
DescripTion
1.5GHz to 3.8GHz
High Linearity
Upconverting Mixer
n GSM/EDGE, W-CDMA, UMTS, LTE and TD-SCDMA
Basestations
n 2.6GHz and 3.5GHz WiMAX Basestations
n 2.4GHz ISM Band Transmitters
n High Performance Transmitters
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.
*Operation over wider frequency range is possible with reduced performance.
Consult Linear Technology for information and assistance.
Frequency Upconversion in 2.14GHz W-CDMA Transmitter
Gain, NF and OIP3 vs
RF Output Frequency
n High Output IP3: +27.3dBm at 2.14GHz
n Low Noise Floor: –158dBm/Hz (POUT = –5dBm)
n High Conversion Gain: 2.6dB at 2.14GHz
n Wide Frequency Range: 1.5GHz to 3.8GHz*
n Low LO Leakage
n Single-Ended RF and LO
n Low LO Drive Level: –1dBm
n Single 3.3V Supply
n 5mm × 5mm QFN24 Package
The LT
®
5579 mixer is a high performance upconverting
mixer optimized for frequencies in the 1.5GHz to 3.8GHz
range. The single-ended LO input and RF output ports
simplify board layout and reduce system cost. The mixer
needs only –1dBm of LO power and the balanced design
results in low LO signal leakage to the RF output. At 2.6GHz
operation, the LT5579 provides high conversion gain of
1.3dB, high OIP3 of +26dBm and a low noise floor of
–157.5dBm/Hz at a –5dBm RF output signal level.
The LT5579 offers a high performance alternative to pas-
sive mixers. Unlike passive mixers, which have conversion
loss and require high LO drive levels, the LT5579 delivers
conversion gain at significantly lower LO input levels and
is less sensitive to LO power level variations. The lower
LO drive level requirements, combined with the excellent
LO leakage performance, translate into lower LO signal
contamination of the output signal.
BIAS
LT5579
RF
GND
LO
VCC
VCC
3.3V
5579 TA01a
1µF
IF+
IF–
40nH
11Ω
11Ω
33pF
82pF
MABAES0061
4:1
82pF
100pF 1nF
0.45pF
RF
OUTPUT
2140MHz
LO INPUT
–1dBm (TYP)
IF
INPUT
240MHz 3.9nH
40nH
RF FREQUENCY (MHz)
1900
0
GAIN (dB), NF (dB), OIP3 (dBm)
5
10
15
20
25
OIP3
SSB NF
GAIN
30
2000 2100 2200 2300
5579 TA01b
2400
TA = 25°C
VCC = 3.3V
fIF = 240MHz
fLO = fRF + fIF
LT5579
2
5579fa
pin conFiguraTionabsoluTe MaxiMuM raTings
Supply Voltage ............................................................4V
LO Input Power .................................................. +10dBm
LO Input DC Voltage........................ –0.3V to VCC + 0.3V
RF Output DC Current ........................................... 60mA
IF Input Power (Differential) ............................... +13dBm
IF+, IF– DC Currents .............................................. 60mA
TJMAX .................................................................... 150°C
Operating Temperature Range .................–40°C to 85°C
Storage Temperature Range .................. –65°C to 150°C
(Note 1)
24 23 22 21 20 19
789
TOP VIEW
25
UH PACKAGE
24-LEAD (5mm s 5mm) PLASTIC QFN
10 11 12
6
5
4
3
2
1
13
14
15
16
17
18
GND
GND
IF+
IF–
GND
GND
GND
GND
GND
RF
GND
GND
GND
GND
LO
GND
GND
GND
GND
VCC
VCC
VCC
VCC
GND
TJMAX = 150°C, θJA = 34°C/W, θJC = 3°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
LT5579IUH#PBF LT5579IUH#TRPBF 5579 24-Lead (5mm × 5mm) Plastic QFN –40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
Consult L
TC 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
VCC = 3.3V, TA = 25°C (Note 3), unless otherwise noted.
PARAMETER CONDITIONS MIN TYP MAX UNITS
Power Supply Requirements (VCC)
Supply Voltage 3.15 3.3 3.6 VDC
Supply Current VCC = 3.3V, PLO = –1dBm
VCC = 3.6V, PLO = –1dBm
226
241
250 mA
mA
Input Common Mode Voltage (VCM) Internally Regulated 570 mV
ac elecTrical characTerisTics
(Notes 2, 3)
PARAMETER CONDITIONS MIN TYP MAX UNITS
IF Input Frequency Range (Note 4) Requires Matching LF to 1000 MHz
LO Input Frequency Range (Note 4) Requires Matching Below 1GHz 750 to 4300 MHz
RF Output Frequency Range (Note 4) Requires Matching 900 to 3900 MHz
LT5579
3
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ac elecTrical characTerisTics
VCC = 3.3V, TA = 25°C, PIF = –5dBm (–5dBm/tone for 2-tone tests,
∆f = 1MHz), PLO = –1dBm, unless otherwise noted. Test circuits are shown in Figure 1. (Notes 2, 3)
PARAMETER CONDITIONS MIN TYP MAX UNITS
IF Input Return Loss ZO = 50Ω, External Match 15 dB
LO Input Return Loss ZO = 50Ω, 1100MHz to 4000MHz >9 dB
RF Output Return Loss ZO = 50Ω, External Match >10 dB
LO Input Power –5 to 2 dBm
VCC = 3.3V, TA = 25°C, PIF = –5dBm (–5dBm/tone for 2-tone tests, ∆f = 1MHz), PLO = –1dBm, unless otherwise noted.
Low side LO for 1750MHz and 3600MHz. High side LO for 2140MHz and 2600MHz. (Notes 2, 3, 4)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Conversion Gain fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
1.8
2.6
1.3
–0.5
dB
dB
dB
dB
Conversion Gain vs Temperature
(TA = –40°C to 85°C)
fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
–0.020
–0.020
–0.027
–0.027
dB/°C
dB/°C
dB/°C
dB/°C
Output 3rd Order Intercept fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
29
27.3
26.2
23.2
dBm
dBm
dBm
dBm
Output 2nd Order Intercept fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
41
42
45
54
dBm
dBm
dBm
dBm
Single Sideband Noise Figure fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
9.2
9.9
12
12
dB
dB
dB
dB
Output Noise Floor (POUT = –5dBm) fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
–159.5
–158.1
–157.5
–155.5
dBm/Hz
dBm/Hz
dBm/Hz
dBm/Hz
Output 1dB Compression fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
13.3
13.9
13.7
10.7
dBm
dBm
dBm
dBm
IF to LO Isolation fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
83
81
74
73
dB
dB
dB
dB
LO to IF Leakage fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
–23
–28
–26
–22
dBm
dBm
dBm
dBm
LO to RF Leakage fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
–39
–35
–36
–35
dBm
dBm
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: Each set of frequency conditions requires appropriate matching
(see Figure 1).
Note 3: The LT5579 is guaranteed functional over the operating
temperature range from –40°C to 85°C.
Note 4: SSB noise figure measurements performed with a small-signal
noise source and bandpass filter on LO signal generator. No other IF signal
applied.
LT5579
4
5579fa
Typical Dc perForMance characTerisTics
Supply Current vs Supply Voltage
Gain Distribution at 3600MHz OIP3 Distribution at 3600MHz
SSB Noise Figure Distribution at
3600MHz
(Test Circuit Shown in Figure 1)
3300MHz to 3800MHz Application:
Typical ac perForMance characTerisTics
VCC = 3.3V, TA = 25°C, fIF = 456MHz, PIF = –5dBm (–5dBm/tone for 2-tone tests, ∆f = 1MHz), low side LO, PLO = –1dBm,
output measured at 3600MHz, unless otherwise noted. (Test circuit shown in Figure 1)
SUPPLY VOLTAGE (V)
3.0
195
SUPPLY CURRENT (mA)
205
215
225
235
255
3.1 3.2 3.3 3.4
5579 G01
3.5 3.6
245
85°C
25°C
–40°C
GAIN (dB)
–2.5
DISTRIBUTION (%)
15
20
25
–1.0 0 1.5
5579 G02
10
5
0
–2.0 –1.5 –0.5 0.5 1.0
TA = 90°C
TA = 25°C
TA = –45°C
OIP3 (dBm)
19
DISTRIBUTION (%)
14
22
5579 G03
8
4
20 21 23
2
0
16
12
10
6
24 25 26
TA = 90°C
TA = 25°C
TA = –45°C
NOISE FIGURE (dB)
10
0
DISTRIBUTION (%)
5
10
15
20
25
30
11 12 13 14
5579 G04
TA = 90°C
TA = 25°C
TA = –45°C
LT5579
5
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Conversion Gain and OIP3
vs RF Output Frequency
SSB Noise Figure
vs RF Output Frequency
LO-RF Leakage
vs RF Output Frequency
Conversion Gain and OIP3
vs LO Input Power
SSB Noise Figure
vs LO Input Power
Conversion Gain and OIP3
vs Supply Voltage
IM3 Level
vs RF Output Power (2-Tone)
IM2 Level
vs RF Output Power (2-Tone)
SSB Noise Figure
vs Supply Voltage
Typical ac perForMance characTerisTics
VCC = 3.3V, TA = 25°C, fIF = 456MHz, PIF = –5dBm (–5dBm/tone for 2-tone tests, ∆f = 1MHz), low side LO, PLO = –1dBm,
output measured at 3600MHz, unless otherwise noted. (Test circuit shown in Figure 1)
3300MHz to 3800MHz Application:
RF FREQUENCY (MHz)
3200 3300
–4
GAIN (dB)
OIP3 (dBm)
4
16
3400 3600 3700
5579 G05
0
12
8
8
16
28
OIP3
GAIN
12
24
20
3500 3800 3900
85°C
25°C
–40°C
RF FREQUENCY (MHz)
3200
NOISE FIGURE (dB)
18
3500
5579 G06
12
8
3300 3400 3600
6
4
20
16
14
10
3700 3800 3900
85°C
25°C
–40°C
RF FREQUENCY (MHz)
3200 3300
–50
LO LEAKAGE (dBm)
–30
0
3400 3600 3700
5579 G07
–40
–10
–20
3500 3800 3900
85°C
25°C
–40°C
RF OUTPUT POWER (dBm/TONE)
–12
–100
IM2 LEVEL (dBc)
–80
–40
–20
0
–8 –4 –2 6
5579 G12
–60
–10 –6 024
85°C
25°C
–40°C
SUPPLY VOLTAGE (V)
3.0
NOISE FIGURE (dB)
10
12
14
3.3 3.5
5579 G13
8
6
43.1 3.2 3.4
16
18
20
3.6
85°C
25°C
–40°C
LO INPUT POWER (dBm)
–17
GAIN (dB)
OIP3 (dBm)
8
12
16
–1
5579 G08
4
GAIN
OIP3
0
–4
18
22
26
14
10
6
–13 –9 –5 3
85°C
25°C
–40°C
LO INPUT POWER (dBm)
–14
NOISE FIGURE (dB)
12
14
16
2
5579 G09
10
8
4–10 –6 –2
6
20
18
85°C
25°C
–40°C
SUPPLY VOLTAGE (V)
3.0
–4
GAIN (dB)
OIP3 (dBm)
0
4
8
12
16
OIP3
GAIN
6
10
14
18
22
26
3.1 3.2 3.3 3.4
5579 G10
3.5 3.6
85°C
25°C
–40°C
LT5579
6
5579fa
Conversion Gain and OIP3
vs RF Output Frequency
SSB Noise Figure
vs RF Output Frequency
LO-RF Leakage
vs RF Output Frequency
Conversion Gain and OIP3
vs LO Input Power
SSB Noise Figure
vs LO Input Power
Conversion Gain and OIP3
vs Supply Voltage
IM3 Level
vs RF Output Power (2-Tone)
IM2 Level
vs RF Output Power (2-Tone)
SSB Noise Figure
vs Supply Voltage
Typical ac perForMance characTerisTics
VCC = 3.3V, TA = 25°C, fIF = 456MHz, PIF = –5dBm (–5dBm/tone for 2-tone tests, ∆f = 1MHz), high side LO, PLO = –1dBm,
output measured at 2600MHz, unless otherwise noted. (Test circuit shown in Figure 1)
2300MHz to 2700MHz Application:
RF FREQUENCY (MHz)
2200
–4
GAIN (dB)
OIP3 (dBm)
0
4
8
12
16
OIP3
GAIN
10
14
18
22
26
30
2300 2400 2500 2600
5579 G14
2700 2800
85°C
25°C
–40°C
RF FREQUENCY (MHz)
2200
NOISE FIGURE (dB)
8
10
12
2500 2700
5579 G15
6
4
22300 2400 2600
14
16
18
2800
85°C
25°C
–40°C
RF FREQUENCY (MHz)
2200
–50
LO LEAKAGE (dBm)
–40
–30
–20
0
–10
2300 2400 2500 2600
5579 G16
2700 2800
85°C
25°C
–40°C
LO INPUT POWER (dBm)
–17
GAIN (dB)
OIP3 (dBm)
8
12
16
–1
5579 G17
4
OIP3
0
–4
20
24
28
16
12
8
–13 –9 –5 3
85°C
25°C
–40°C
GAIN
SUPPLY VOLTAGE (V)
3.0
–4
GAIN (dB)
OIP3 (dBm)
0
4
8
16
12
8
12
16
20
28
24
3.1 3.2 3.3
OIP3
GAIN
3.4
5579 G19
3.5 3.6
85°C
25°C
–40°C
RF OUTPUT POWER (dBm/TONE)
–12
–100
IM3 LEVEL (dBc)
–80
–40
–20
0
–8 –4 –2 6
5579 G20
–60
–10 –6 024
85°C
25°C
–40°C
RF OUTPUT POWER (dBm/TONE)
–12
–100
IM2 LEVEL (dBc)
–80
–40
–20
0
–8 –4 –2 6
5579 G21
–60
–10 –6 024
85°C
25°C
–40°C
SUPPLY VOLTAGE (V)
3.0
NOISE FIGURE (dB)
8
10
12
3.3 3.5
5579 G22
6
4
23.1 3.2 3.4
14
16
18
3.6
85°C
25°C
–40°C
LT5579
7
5579fa
Conversion Gain and OIP3
vs RF Output Frequency
SSB Noise Figure
vs RF Output Frequency
LO-RF Leakage
vs RF Output Frequency
Conversion Gain and OIP3
vs LO Input Power
SSB Noise Figure
vs LO Input Power
Conversion Gain and OIP3
vs Supply Voltage
IM3 Level
vs RF Output Power (2-Tone)
IM2 Level
vs RF Output Power (2-Tone)
SSB Noise Figure
vs Supply Voltage
Typical perForMance characTerisTics
VCC = 3.3V, TA = 25°C, fIF = 240MHz, PIF = –5dBm (–5dBm/tone for 2-tone tests, ∆f = 1MHz), high side LO, PLO = –1dBm,
output measured at 2140MHz, unless otherwise noted. (Test circuit shown in Figure 1)
2140MHz Application:
RF FREQUENCY (MHz)
1950
GAIN (dB)
OIP3 (dBm)
4
8
2350
5579 G23
0
–4 2050 2150
GAIN
OIP3
2250
16
12
18
22
14
10
30
26
85°C
25°C
–40°C
RF FREQUENCY (MHz)
1950
NOISE FIGURE (dB)
10
12
14
2350
5579 G24
8
6
22050 2150 2250
4
18
16
85°C
25°C
–40°C
RF FREQUENCY (MHz)
1950
LO LEAKAGE (dBm)
–30
–20
2350
5579 G25
–40
–50 2050 2150 2250
0
–10
85°C
25°C
–40°C
LO INPUT POWER (dBm)
–17
GAIN (dB)
OIP3 (dBm)
8
12
16
–1
5579 G26
4
OIP3
0
–4
22
26
30
18
14
10
–13 –9 –5 3
85°C
25°C
–40°C
GAIN
LO INPUT POWER (dBm)
–14
NOISE FIGURE (dB)
10
12
14
2
5579 G27
8
6
2–10 –6 –2
4
18
16
85°C
25°C
–40°C
SUPPLY VOLTAGE (V)
3.0
–4
GAIN (dB)
OIP3 (dBm)
0
4
8
16
12
10
14
18
22
30
26
3.1 3.2 3.3 3.4
GAIN
OIP3
5579 G19
3.5 3.6
85°C
25°C
–40°C
SUPPLY VOLTAGE (V)
3.0
NOISE FIGURE (dB)
10
12
14
3.3 3.5
5579 G31
8
6
4
2
3.1 3.2 3.4
16
18
3.6
85°C
25°C
–40°C
LT5579
8
5579fa
Conversion Gain and OIP3
vs RF Output Frequency
SSB Noise Figure
vs RF Output Frequency
LO-RF Leakage
vs RF Output Frequency
Conversion Gain and OIP3
vs LO Input Power
SSB Noise Figure
vs LO Input Power
Conversion Gain and OIP3
vs Supply Voltage
IM3 Level
vs RF Output Power (2-Tone)
IM2 Level
vs RF Output Power (2-Tone)
SSB Noise Figure
vs Supply Voltage
Typical perForMance characTerisTics
VCC = 3.3V, TA = 25°C, fIF = 240MHz, PIF = –5dBm (–5dBm/tone for 2-tone tests, ∆f = 1MHz), low side LO, PLO = –1dBm,
output measured at 1750MHz, unless otherwise noted. (Test circuit shown in Figure 1)
1750MHz Application:
RF FREQUENCY (MHz)
1650
GAIN (dB)
OIP3 (dBm)
8
12
16
1850
5579 G32
4
OIP3
0
–4
22
26
30
18
14
10
1700 1750 1800 1900
85°C
25°C
–40°C
GAIN
RF FREQUENCY (MHz)
1650
NOISE FIGURE (dB)
8
10
12
1800 1900
5579 G33
6
4
21700 1750 1850
14
16
18
85°C
25°C
–40°C
RF FREQUENCY (MHz)
1650
LO LEAKAGE (dBm)
–20
–10
0
1850
5579 G34
–30
–40
–50 1700 1750 1800 1900
85°C
25°C
–40°C
LO INPUT POWER (dBm)
–17
GAIN (dB)
OIP3 (dBm)
8
12
16
–1
5579 G35
4
OIP3
0
–4
22
26
30
18
14
10
–13 –9 –5 3
85°C
25°C
–40°C
GAIN
SUPPLY VOLTAGE (V)
3.0
–4
GAIN (dB)
OIP3 (dBm)
0
4
8
12
16
OIP3
GAIN
12
16
20
24
28
32
3.1 3.2 3.3 3.4
5579 G37
3.5 3.6
85°C
25°C
–40°C
SUPPLY VOLTAGE (V)
3.0
NOISE FIGURE (dB)
8
10
12
3.3 3.5
5579 G40
6
4
23.1 3.2 3.4
14
16
18
3.6
85°C
25°C
–40°C
LT5579
9
5579fa
pin FuncTions
GND (Pins 1, 2, 5-7, 12-14, 16-18, 19-21, 23, 24): Ground
Connections. These pins are internally connected to the
exposed pad and should be soldered to a low impedance
RF ground on the printed circuit board.
IF+, IF– (Pins 3, 4): Differential IF Input. The common
mode voltage on these pins is set internally to 570mV. The
DC current from each pin is determined by the value of
an external resistor to ground. The maximum DC current
through each pin is 60mA.
VCC (Pins 8-11): Power Supply Pins for the IC. These
pins are connected together internally. Typical current
consumption is 226mA. These pins should be connected
together on the circuit board with external bypass capaci-
tors of 1000pF, 100pF and 10pF located as close to the
pins as possible.
RF (Pin 15): Single-Ended RF Output. This pin is con-
nected to an internal transformer winding. The opposite
end of the winding is grounded internally. An impedance
transformation may be required to match the output and a
DC decoupling capacitor is required if the following stage
has a DC bias voltage present.
LO (Pin 22): Single-Ended Local Oscillator Input. An internal
series capacitor acts as a DC block to this pin.
Exposed Pad (Pin 25): PGND. Electrical and thermal
ground connection for the entire IC. This pad must be
soldered to a low impedance RF ground on the printed
circuit board. This ground must also provide a path for
thermal dissipation.
LT5579
10
5579fa
block DiagraM
LO BUFFER
LO
GND PINS ARE NOT SHOWN
DOUBLE
BALANCED
MIXER
RF
VCC
22
11
15
EXPOSED
PAD
25
VCC
VCC
VCC
5579 BD
BIAS
IF+IF–
VCM
CTRL
VCC2
VCC2
10
9
8
3 4
LT5579
11
5579fa
TesT circuiT
GND
GND
GND
IF+
IF–
GND
GND
18
17
16
15
14
13
1
2
3
4
5
6
GND
GND
GND
RF
GND
GND
GND
GND
LO
GND
GND
GND
GND
VCC
VCC
VCC
VCC
GND
C3C9
C4
C1
IF
INPUT
RF
OUTPUT
T1
4:1
C2
L1
TL1
L2
R1
LO INPUT
R2
C5
7 8 9 10 11 12
24 23 22 21 20 19
C6 C7
VCC
C8
5579 F01
L3
TL2 TL3
REF DES
fRF = 1750MHz
fIF = 240MHz
fRF = 2140MHz
fIF = 240MHz
fRF = 2600MHz
fIF = 456MHz
fRF = 3600MHz
fIF = 456MHz
SIZE
COMMENTS
C1, C2 82pF 82pF 33pF 33pF 0402 AVX
C3 — — 2.7pF 1.8pF 0402 AVX
C4 100pF 100pF 100pF 100pF 0402 AVX
C5 10pF 10pF 10pF 10pF 0603 AVX
C6 1nF 1nF 1nF 1nF 0402 AVX
C7 1µF 1µF 1µF 1µF 0603 Taiyo Yuden LMK107BJ105MA
C8 1.2pF 0.45pF — 0.7pF 0402 AVX ACCU-P
C9 33pF 33pF 33pF 33pF 0402 AVX
L1, L2 40nH 40nH 40nH 40nH 0402 Coilcraft 0402CS
L3 6.8nH 3.9nH 1nH 0Ω 0402 Toko LL1005-FHL/0Ω Jumper
R1, R2 11Ω, 0.1% 11Ω, 0.1% 11Ω, 0.1% 11Ω, 0.1% 0603 IRC PFC-W0603R-03-11R1-B
T1 4:1 4:1 4:1 4:1 SM-22 M/A-COM MABAES0061
TL1, TL2* — — 1mm 1.4mm — ZO = 70Ω Microstrip
TL3 2mm 2mm 2mm 2mm — ZO = 70Ω Microstrip
*Center-to-center spacing between C9 and C3. Center of C9 is 2.6mm from the edge of the IC package for all cases.
Figure 1. Test Circuit Schematic
LT5579
12
5579fa
applicaTions inForMaTion
The LT5579 uses a high performance LO buffer amplifier
driving a double-balanced mixer core to achieve frequency
conversion with high linearity. Internal baluns are used to
provide single-ended LO input and RF output ports. The
IF input is differential. The LT5579 is intended for opera-
tion in the 1.5GHz to 3.8GHz frequency range, though
operation outside this range is possible with reduced
performance.
IF Input Interface
The IF inputs are tied to the emitters of the double-balanced
mixer transistors, as shown in Figure 2. These pins are
internally biased to a common mode voltage of 570mV.
The optimum DC current in the mixer core is approximately
50mA per side, and is set by the external resistors, R1 and
R2. The inductors and resistors must be able to handle
the anticipated current and power dissipation. For best
LO leakage performance the board layout must be sym-
metrical and the input resistors should be well matched
(0.1% tolerance is recommended).
The purpose of the inductors (L1 and L2) is to reduce the
loading effects of R1 and R2. The impedances of L1 and L2
should be at least several times greater than the IF input
impedance at the desired IF frequency. The self-resonant
frequency of the inductors should also be at least several
times the IF frequency. Note that the DC resistances of
L1 and L2 will affect the DC current and may need to be
accounted for in the selection of R1 and R2.
L1 and L2 should connect to the signal lines as close to
the package as possible. This location will be at the lowest
impedance point, which will minimize the sensitivity of the
performance to the loading of the shunt L-R branches.
Capacitors C1 and C2 are used to cancel out the parasitic
series inductance of the IF transformer. They also provide
DC isolation between the IF ports to prevent unwanted inter-
actions that can affect the LO to RF leakage performance.
The differential input resistance to the mixer is approxi-
mately 10Ω, as indicated in Table 1. The package and
external inductances (TL1 and TL2) are used along with
C3 VCC
50mA
570mV
570mV
50mA
2k
2k
IF+
LT5579
C9
C1
IF
INPUT T1
4:1
C2
L1
L2
R1
R2
5579 F02
3
IF–
4
TL1
TL2
Figure 2. IF Input with External Matching
LT5579
13
5579fa
applicaTions inForMaTion
C9 to step the impedance up to about 12.5Ω. At lower
frequencies additional series inductance may be required
between the IF ports and C9. The position of C9 may vary
with the IF frequency due to the different series inductance
requirements. The 4:1 impedance ratio of transformer T1
completes the transformation to 50 ohms. Table 1 lists the
differential IF input impedances and reflection coefficients
for several frequencies.
Table 1. IF Input Differential Impedance
FREQUENCY
(MHz)
IF INPUT
IMPEDANCE
REFLECTION COEFFICIENT
MAG ANGLE
70 8.8+j1.3 0.70 177
140 8.7+j2.3 0.70 175
170 9.0+j2.8 0.70 174
190 8.9+j3.0 0.70 173
240 9.0+j4.0 0.70 170
380 9.7+j4.9 0.68 168
450 10.0+j5.2 0.67 167
750 10.8+j9.4 0.65 158
1000 11.8+j13.8 0.64 148
The purpose of capacitor C3 is to improve the LO-RF
leakage in some applications. This relatively small-valued
capacitor has little effect on the impedance match in most
cases. This capacitor should typically be located close to
the IC, however, there may be cases where re-positioning
the capacitor may improve performance.
The measured return loss of the IF input is shown in
Figure 3 for application frequencies of 70MHz, 240MHz
and 456MHz. Component values are listed in Table 2. (For
70MHz matching details, refer to Figure 8.)
Table 2. IF Input Component Values
FREQUENCY
(MHz)
C1, C2
(pF)
C9
(pF)
C3
(pF)
L1, L2
(nH)
R1, R2
(Ω)
MATCH BW
(at 12dB RL)
70(3) 1000 120 (1) 100 9.1 <50 to 158
140 180 22 (1) 100 9.1 112 to 170
240 82 33 (1) 40 11 174 to 263
450 33 33 (1) 40 11 330 to 505
Note: (1) Depends on RF, (2) T1 = M/A-Com MABAES0061,
(3) See Figure 8
FREQUENCY (MHz)
0
RETURN LOSS (dB)
–10
–5
0
300 500 800
5579 F03
–15
–20
–25
100 200
ab
c
400 600 700
Figure 3. IF Input Return Loss with 70MHz (a),
240MHz (b) and 456MHz (c) Matching
LT5579
14
5579fa
applicaTions inForMaTion
LO Input Interface
The simplified schematic for the single-ended LO input port
is shown in Figure 4. An internal transformer provides a
broadband impedance match and performs single-ended
to differential conversion. An internal capacitor also aids
in impedance matching and provides DC isolation to the
primary transformer winding. The transformer secondary
feeds the differential limiting amplifier stages that drive
the mixer core.
The measured return loss of the LO input port is shown
in Figure 5 for an LO input power of –1dBm. The imped-
ance match is acceptable from about 1.1GHz to beyond
4GHz, with a minimum return loss across this range of
about 9dB at 2300MHz. If desired, the return loss can
be improved below 1.1GHz by external components as
shown in Figure 4. The return loss can also be improved
by reducing the LO drive level, though performance will
degrade if the level is too low.
While external matching of the LO input is not required
for frequencies above 1.1GHz, external matching should
be used for lower LO frequencies for best performance.
Table 3 lists the input impedance and reflection coefficient
vs frequency for the LO input for use in such cases.
Table 3. Single-Ended LO Input Impedance
(at Pin 22, No External Match)
FREQUENCY
(MHz)
INPUT
IMPEDANCE
REFLECTION COEFFICIENT
MAG ANGLE
750 63.3||– j30.5 0.68 –125
1000 20.3||– j1120 0.42 –179
1500 78.4||– j1250 0.22 –7.7
1900 79.1||– j113 0.34 –65.2
2000 74.7||– j96.3 0.35 –74.7
2150 66.8||– j81.5 0.36 –87.0
2400 53.8||– j69.8 0.35 –105
3050 33.7||– j115 0.26 –148
3150 33.0||– j146 0.24 –154
4000 43.9||+ j173 0.15 123
VBIAS
VCC
LO
C13
5579 F04
L6
LO
INPUT
EXTERNAL
MATCHING
FOR LOW
FREQUENCY
ONLY
22
Figure 4. LO Input Circuit
FREQUENCY (MHz)
500 1000
–25
RETURN LOSS (dB)
–15
0
1500 2500 3000
5579 F05
–20
–5
–10
2000 3500 4000
Figure 5. LO Input Return Loss
LT5579
15
5579fa
15
118 109
VCC
C8
5579 F06
LT5579
L3
RF
50Ω
Figure 6. RF Output Circuit
FREQUENCY (MHz)
1500
RETURN LOSS (dB)
–10
–5
0
3500
5579 F07
–15
–20
–25
a b
c
d
2000 2500 3000 4000
Figure 7. RF Output Return Loss with 1750MHz (a),
2140MHz (b), 2600MHz (c) and 3600MHz (d) Matching
RF Output Interface
The RF output interface is shown in Figure 6. An internal
RF transformer reduces the mixer core output impedance
to simplify matching of the RF output pin. A center tap in
the transformer provides the DC connection to the mixer
core and the transformer provides DC isolation to the RF
output. The RF pin is internally grounded through the
secondary winding of the transformer, thus a DC voltage
should not be applied to this pin.
While the LT5579 performs best at frequencies above
1500MHz, the part can be used down to 900MHz. The
internal RF transformer is not optimized for these lower
frequencies, thus the gain and impedance matching band-
width will decrease due to the low transformer inductance.
The impedance data for the RF output, listed in Table 4,
can be used to develop matching networks for different
frequencies or load impedances. Figure 7 illustrates the
output return loss performance for several applications.
The component values and approximate matching band-
widths are listed in Table 5.
DC and RF Grounding
The L
T5579 relies on the back side ground for both RF and
thermal performance. The Exposed Pad must be soldered
to the low impedance topside ground plane of the board.
Several vias should connect the topside ground to other
ground layers to aid in thermal dissipation.
Table 4. Single-Ended RF Output Impedance
(at Pin 15, No External Matching)
FREQUENCY
(MHz)
RF OUTPUT
IMPEDANCE
REFLECTION COEFFICIENT
MAG ANGLE
1250 11.0+j42.7 0.78 97.4
1750 55.6+j83.4 0.62 47.8
1950 119+j62.4 0.52 21.9
2150 116–j21.0 0.42 –10.4
2300 73.7–j37.7 0.34 –40.9
2600 35.2–j21.5 0.30 –110
3600 21.9+j17.8 0.45 134
Table 5. RF Output Component Values
FREQUENCY
(MHz)
C8 (pF)
L3 (nH)
MATCH BW (at 12dB RL)
1650 1.5 6.8 1630 to 1770
1750 1.2 6.8 1725 to 1870
1950 1 4.7 1840 to 2020
2140 0.45 3.9 2035 to 2285
2600 – 1 2260 to 2780*
3600 0.7 0Ω 3170 to 4100*
*10dB Return Loss bandwidth
applicaTions inForMaTion
LT5579
16
5579fa
The following examples illustrate the implementation
and performance of the LT5579 in different frequency
configurations. These circuits were evaluated using the
circuit board shown in Figure 12.
1650MHz Application
In this case, the LT5579 was evaluated while tuned for an
IF of 70MHz and an RF output of 1650MHz. The matching
configuration is shown in Figure 8.
Input capacitors are used only as DC blocks in this ap-
plication. The 4.7nH inductors and the 120pF capacitor
transform the input impedance of the IC up to approximately
12.5Ω. The relatively low input frequency demanded the
use of 4.7nH chip inductors instead of short transmission
lines.
Closer to the IC input, 47pF capacitors were used instead
of a single differential capacitor (C3 in Figure 1), because it
was found that the addition of common mode capacitance
improved the high side LO performance in this applica-
tion. The value of these 47pF capacitors was selected to
resonate with the 100nH inductors at 70MHz. Note that
adding common mode capacitance does not improve
performance with all frequency configurations.
The RF port impedance match was realized with C8 =
1.5pF and L3 = 6.8nH. The optimum impedance match
120pF
1.5pF
1nF
47pF
9.1Ω
100nH
100nH
MABAES0061
4:1
1nF
4.7nH
4.7nH
IF
70MHz
LO
RF
1650MHz
6.8nH
9.1Ω
47pF
5579 F08
Figure 8. IF Input Tuned for 70MHz
RF OUTPUT FREQUENCY (MHz)
1550
GAIN (dB), NF (dB), OIP3 (dBm)
15
20
25
1750
5579 F09
10
5
–5 1600 1650 1700
0
35 OIP3
SSB NF
GAIN
30
LOW SIDE LO
HIGH SIDE LO
TA = 25°C
fIF = 70MHz
PIF = –5dBm/TONE
PLO = –1dBm
Figure 9. Gain, Noise Figure and OIP3 vs
RF Frequency with 70MHz IF and 1650MHz RF
Typical applicaTions
was purposefully shifted high in order to achieve better
OIP3 performance at the desired frequency.
Figure 9 shows the measured conversion gain and OIP3
as a function of RF output frequency. As mentioned above,
the output impedance match is shifted towards the high
side of the band, and this is evidenced by the positive slope
of the gain. The single sideband noise figure across the
frequency range is also shown.
Curves for both high side and low side LO cases are
shown. In this particular application, the low side OIP3
outperforms the high side case.
1950MHz Application
In this example, a high side LO was used to convert the IF
input signal at 240MHz to 1950MHz at the RF output. The
RF port impedance match was realized with C8 = 1pF and
L3 = 4.7nH. As in the 1650MHz case, it was found that
tuning the output match slightly high in frequency gave
better OIP3 results at the desired frequency. The input
match for 240MHz operation is the same as described in
the test circuit of Figure 1.
The measured 1950MHz performance is plotted in Fig-
ure 10 for both low side and high side LO drive. With this
matching configuration, the low side LO case outperforms
the high side LO. The gain, noise figure (SSB) and OIP3
are plotted as a function of RF output frequency.
LT5579
17
5579fa
RF OUTPUT FREQUENCY (MHz)
1800
25
30
35
2000
5579 F10
20
15
1850 1900 1950 2050
10
5
0
GAIN (dB), NF (dB), OIP3 (dBm)
OIP3
SSB NF
GAIN
LOW SIDE LO
HIGH SIDE LO
TA = 25°C
fIF = 240MHz
PIF = –5dBm/TONE
PLO = –1dBm
Figure 10. Gain, Noise Figure and OIP3 vs
RF Frequency for the 1950MHz Application
Typical applicaTions
2140MHz with Low Side LO
The LT5579 was fully characterized with an RF output of
2140MHz and a high side LO. The part also works well
when driven with low side LO, however, the performance
RF OUTPUT FREQUENCY (MHz)
2000
0
GAIN (dB), NF (dBm), OIP3 (dBm)
5
10
15
20
30
2050 2100 2150
OIP3
SSB NF
GAIN
2200
5579 F11
2250 2300
25
TA = 25°C
fIF = 240MHz
PIF = –5dBm/TONE
PLO = –1dBm
fRF = fIF + fLO
Figure 11. Measured Performance when Tuned
for 240MHz IF, 2140MHz RF and Low Side LO
Figure 12. LT5579 Evaluation Board (DC1233A)
benefited from the addition of common mode capacitance
to the IF input match. A 10pF capacitor to ground was
added to each IF pin. These capacitors were attached
near inductors L1 and L2. The measured performance is
shown in Figure 11.
LT5579
18
5579fa
package DescripTion
UH Package
24-Lead Plastic QFN (5mm × 5mm)
(Reference LTC DWG # 05-08-1747 Rev A)
5.00 p 0.10
5.00 p 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 p 0.10
23
1
2
24
BOTTOM VIEW—EXPOSED PAD
3.25 REF
3.20 p 0.10
3.20 p 0.10
0.75 p 0.05 R = 0.150
TYP
0.30 p 0.05
(UH24) QFN 0708 REV A
0.65 BSC
0.200 REF
0.00 – 0.05
0.75 p0.05
3.25 REF
3.90 p0.05
5.40 p0.05
0.30 p 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 s 45o
CHAMFER
R = 0.05
TYP
3.20 p 0.05
3.20 p 0.05
LT5579
19
5579fa
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.
revision hisTory
REV DATE DESCRIPTION PAGE NUMBER
A 6/10 Revised Typical Application drawing.
Revised Absolute Maximum Ratings, Pin Configuration and DC Electrical Characteristics sections.
Revised AC Electrical Characteristics section parameters and Note 3.
Revised Figure 1 table.
Update Tables 2, 3 and 5 in Applications Information section
Added Typical Application drawing and graph, and revised Related Parts list
1
2
3
11
13, 14, 15
20
LT5579
20
5579fa
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
LINEAR TECHNOLOGY CORPORATION 2008
LT 0610 REV A • PRINTED IN USA
BIAS
LT5579
RF
GND
LO
VCC
VCC
3.3V
5579 TA02a
1µF
IF+
IF–
40nH
11Ω
11Ω
33pF
33pF
MABAES0061
4:1
33pF
2.7pF
100pF 1nF
RF
OUTPUT
2650MHz
LO INPUT
–1dBm (TYP)
IF
INPUT
380MHz 1nH
40nH
relaTeD parTs
Typical applicaTion
2650MHz LTE Downlink Transmitter
Gain and OIP3 vs
RF Output Frequency
RF FREQUENCY (MHz)
2500 2550
0
GAIN (dB)
5
4
3
2
1
6
7
8
9
OIP3
10
18
OIP3 (dBm)
23
22
21
20
19
24
25
26
27
28
2600 2650 2700 2750
5579 TA02b
2800
TA = 25°C
VCC = 3.3V
fIF = 380MHz
LOW-SIDE LO
HIGH-SIDE LO
GAIN
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
LTC6400-X 300MHz Low Distortion IF Amp/ADC Driver Fixed Gain of 8dB, 14dB, 20dB and 26dB; >36dBm OIP3 at 300MHz, Differential I/O
LTC6401-X 140MHz Low Distortion IF Amp/ADC Driver Fixed Gain of 8dB, 14dB, 20dB and 26dB; >40dBm OIP3 at 140MHz, Differential I/O
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
LT5554 Ultralow Distort IF Digital VGA 48dBm OIP3 at 200MHz, 2dB to 18dB Gain Range, 0.125dB Gain Steps
LT5575 700MHz to 2.7GHz Direct Conversion I/Q
Demodulator
Integrated Baluns, 28dBm IIP3, 13dBm P1dB, 0.03dB I/Q Amplitude Match,
0.4° Phase Match
LT5578 400MHz to 2.7GHz Upconverting Mixer 27dBm OIP3 at 900MHz, 24.2dBm at 1.95GHz, Integrated RF Transformer
LTC5598 5MHz to 1.6GHz I/Q Modulator 27.7dBm OIP3 at 140MHz, 22.9dBm at 900MHz, –161.2dBm/Hz Noise Floor
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
LT5537 Wide Dynamic Range Log RF/IF Detector Low Frequency to 1GHz, 83dB Log Linear Dynamic Range
LT5570 2.7GHz Mean-Squared Detector ±0.5dB Accuracy Over Temperature and >50dB Dynamic Range, 500ns Rise Time
LT5581 6GHz Low Power RMS Detector 40dB Dynamic Range, ±1dB Accuracy Over Temperature, 1.5mA Supply Current
ADCs
LTC2208 16-Bit, 130Msps ADC 78dBFS Noise Floor, >83dB SFDR at 250MHz
LTC2262-14 14-Bit, 150Msps ADC Ultralow Power 72.8dB SNR, 88dB SFDR, 149mW Power Consumption
LTC2242-12 12-Bit, 250Msps ADC 65.4dB SNR, 78dB SFDR, 740mW Power Consumption