LT5579 - 1.5GHz to 3.8GHz High Linearity Upconverting Mixer

LT5579
1.5GHz to 3.8GHz
High Linearity
Upconverting Mixer
Features
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Description
High Output IP3: +27.3dBm at 2.14GHz
Low Noise Floor: –158dBm/Hz (POUT = –5dBm)
High Conversion Gain: 2.6dB at 2.14GHz
Wide Frequency Range: 1.5GHz to 3.8GHz*
Low LO Leakage
Single-Ended RF and LO
Low LO Drive Level: –1dBm
Single 3.3V Supply
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 passive 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.
Applications
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
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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.
Typical Application
Frequency Upconversion in 2.14GHz W-CDMA Transmitter
LO INPUT
–1dBm (TYP)
Gain, NF and OIP3 vs
RF Output Frequency
LO
30
GND
BIAS
11Ω
IF
INPUT MABAES0061
82pF
240MHz
4:1
40nH
IF+
0.45pF
33pF
82pF
3.9nH
RF
IF–
OIP3
25
20
TA = 25°C
VCC = 3.3V
fIF = 240MHz
fLO = fRF + fIF
15
VCC
1µF
100pF
5579 TA01a
1nF
VCC
3.3V
SSB NF
10
5
0
1900
40nH
11Ω
RF
OUTPUT
2140MHz
GAIN (dB), NF (dB), OIP3 (dBm)
LT5579
GAIN
2000
2100
2200
2300
RF FREQUENCY (MHz)
2400
5579 TA01b
5579fa
LT5579
Pin Configuration
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
GND
GND
GND
LO
GND
GND
TOP VIEW
24 23 22 21 20 19
GND 1
18 GND
GND 2
17 GND
IF+ 3
16 GND
25
IF– 4
15 RF
GND 5
14 GND
GND 6
13 GND
GND
VCC
9 10 11 12
VCC
8
VCC
7
VCC
(Note 1)
GND
Absolute Maximum Ratings
UH PACKAGE
24-LEAD (5mm s 5mm) PLASTIC QFN
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 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
VCC = 3.3V, TA = 25°C (Note 3), unless otherwise noted.
CONDITIONS
MIN
TYP
MAX
UNITS
Power Supply Requirements (VCC)
Supply Voltage
3.3
3.6
VDC
Supply Current
VCC = 3.3V, PLO = –1dBm
VCC = 3.6V, PLO = –1dBm
3.15
226
241
250
mA
mA
Input Common Mode Voltage (VCM)
Internally Regulated
570
AC Electrical Characteristics
mV
(Notes 2, 3)
PARAMETER
CONDITIONS
IF Input Frequency Range (Note 4)
Requires Matching
MIN
LF to 1000
TYP
MAX
UNITS
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
5579fa
LT5579
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
IF Input Return Loss
LO Input Return Loss
RF Output Return Loss
LO Input Power
CONDITIONS
ZO = 50Ω, External Match
ZO = 50Ω, 1100MHz to 4000MHz
ZO = 50Ω, External Match
MIN
TYP
15
>9
>10
–5 to 2
MAX
UNITS
dB
dB
dB
dBm
MAX
UNITS
dB
dB
dB
dB
dB/°C
dB/°C
dB/°C
dB/°C
dBm
dBm
dBm
dBm
dBm
dBm
dBm
dBm
dB
dB
dB
dB
dBm/Hz
dBm/Hz
dBm/Hz
dBm/Hz
dBm
dBm
dBm
dBm
dB
dB
dB
dB
dBm
dBm
dBm
dBm
dBm
dBm
dBm
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
Conversion Gain
Conversion Gain vs Temperature (TA = –40°C to 85°C)
Output 3rd Order Intercept
Output 2nd Order Intercept
Single Sideband Noise Figure
Output Noise Floor (POUT = –5dBm)
Output 1dB Compression
IF to LO Isolation
LO to IF Leakage
LO to RF Leakage
CONDITIONS
fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
fIF = 240MHz, fRF = 1750MHz
fIF = 240MHz, fRF = 2140MHz
fIF = 456MHz, fRF = 2600MHz
fIF = 456MHz, fRF = 3600MHz
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).
MIN
TYP
1.8
2.6
1.3
–0.5
–0.020
–0.020
–0.027
–0.027
29
27.3
26.2
23.2
41
42
45
54
9.2
9.9
12
12
–159.5
–158.1
–157.5
–155.5
13.3
13.9
13.7
10.7
83
81
74
73
–23
–28
–26
–22
–39
–35
–36
–35
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.
5579fa
LT5579
Typical DC Performance Characteristics
(Test Circuit Shown in Figure 1)
Supply Current vs Supply Voltage
255
SUPPLY CURRENT (mA)
245
235
225
215
85°C
25°C
–40°C
205
195
3.0
3.1
3.2
3.3
3.4
SUPPLY VOLTAGE (V)
3.5
3.6
5579 G01
Typical AC Performance Characteristics
3300MHz to 3800MHz Application:
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)
Gain Distribution at 3600MHz
14
12
15
10
TA = 90°C
TA = 25°C
TA = –45°C
25
10
8
6
20
15
10
4
5
0
–2.5 –2.0 –1.5 –1.0 –0.5 0
GAIN (dB)
30
TA = 90°C
TA = 25°C
TA = –45°C
DISTRIBUTION (%)
DISTRIBUTION (%)
20
16
TA = 90°C
TA = 25°C
TA = –45°C
DISTRIBUTION (%)
25
SSB Noise Figure Distribution at
3600MHz
OIP3 Distribution at 3600MHz
5
2
0.5
1.0 1.5
5579 G02
0
19
20
21
23
22
OIP3 (dBm)
24
25
26
5579 G03
0
10
11
12
13
NOISE FIGURE (dB)
14
5579 G04
5579fa
LT5579
Typical AC Performance Characteristics
3300MHz to 3800MHz Application:
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)
Conversion Gain and OIP3
vs RF Output Frequency
SSB Noise Figure
vs RF Output Frequency
28
OIP3
20
85°C
25°C
–40°C
4
16
GAIN
14
12
10
8
12
0
–10
16
NOISE FIGURE (dB)
8
18
24
OIP3 (dBm)
GAIN (dB)
12
0
20
LO LEAKAGE (dBm)
16
LO-RF Leakage
vs RF Output Frequency
8
–4
3200 3300 3400 3500 3600 3700 3800 3900
RF FREQUENCY (MHz)
4
3200 3300 3400 3500 3600 3700 3800 3900
RF FREQUENCY (MHz)
5579 G05
–50
3200 3300 3400 3500 3600 3700 3800 3900
RF FREQUENCY (MHz)
5579 G07
SSB Noise Figure
vs LO Input Power
16
26
12
22
Conversion Gain and OIP3
vs Supply Voltage
16
20
0
12
16
14
12
10
–13
–5
–1
–9
LO INPUT POWER (dBm)
3
4
–14
6
–6
–10
–2
LO INPUT POWER (dBm)
5579 G08
4
2
–4
3.0
3.1
3.2
3.3
3.4
SUPPLY VOLTAGE (V)
0
–20
–20
6
3.6
3.5
5579 G10
IM2 Level
vs RF Output Power (2-Tone)
0
14
10
5579 G09
IM3 Level
vs RF Output Power (2-Tone)
18
85°C
25°C
–40°C
0
85°C
25°C
–40°C
6
–4
–17
8
GAIN
8
10
22
OIP3
GAIN (dB)
GAIN (dB)
14
GAIN
26
OIP3 (dBm)
4
OIP3 (dBm)
18
85°C
25°C
–40°C
NOISE FIGURE (dB)
18
8
85°C
25°C
–40°C
5579 G06
Conversion Gain and OIP3
vs LO Input Power
OIP3
–30
–40
85°C
25°C
–40°C
6
–20
SSB Noise Figure
vs Supply Voltage
20
–40
–60
–80
–100
2
4
–12 –10 –8 –6 –4 –2 0
RF OUTPUT POWER (dBm/TONE)
–40
–60
–80
85°C
25°C
–40°C
6
5579 G11
16
NOISE FIGURE (dB)
IM2 LEVEL (dBc)
IM3 LEVEL (dBc)
18
12
10
8
85°C
25°C
–40°C
–100
2
4
–12 –10 –8 –6 –4 –2 0
RF OUTPUT POWER (dBm/TONE)
14
85°C
25°C
–40°C
6
6
5579 G12
4
3.0
3.1
3.2
3.4
3.3
SUPPLY VOLTAGE (V)
3.5
3.6
5579 G13
5579fa
LT5579
Typical AC Performance Characteristics
2300MHz to 2700MHz Application:
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)
Conversion Gain and OIP3
vs RF Output Frequency
SSB Noise Figure
vs RF Output Frequency
16
30
LO-RF Leakage
vs RF Output Frequency
0
18
85°C
25°C
–40°C
16
26
18
0
NOISE FIGURE (dB)
GAIN (dB)
GAIN
4
22
85°C
25°C
–40°C
OIP3 (dBm)
8
–10
14
OIP3
LO LEAKAGE (dBm)
12
12
10
8
6
14
–4
2200
2300
2
2200
10
2800
2400 2500 2600 2700
RF FREQUENCY (MHz)
2300
2400
2500 2600 2700
RF FREQUENCY (MHz)
–30
–40
85°C
25°C
–40°C
4
–20
–50
2200
2800
2300
2400 2500 2600 2700
RF FREQUENCY (MHz)
5579 G16
5579 G15
5579 G14
Conversion Gain and OIP3
vs LO Input Power
SSB Noise Figure
vs LO Input Power
16
28
12
24
Conversion Gain and OIP3
vs Supply Voltage
16
18
28
16
16
0
GAIN (dB)
GAIN (dB)
GAIN
4
12
10
8
6
12
–4
–17
–13
–5
–1
–9
LO INPUT POWER (dBm)
3
8
2
–14
–6
–10
–2
LO INPUT POWER (dBm)
5579 G17
85°C
25°C
–40°C
8
GAIN
4
16
2
–4
12
3.0
3.1
3.4
3.2
3.3
SUPPLY VOLTAGE (V)
3.5
IM2 Level
vs RF Output Power (2-Tone)
0
0
–20
–20
8
3.6
5579 G19
5579 G18
IM3 Level
vs RF Output Power (2-Tone)
20
0
85°C
25°C
–40°C
4
24
OIP3 (dBm)
20
OIP3 (dBm)
85°C
25°C
–40°C
8
OIP3
12
14
NOISE FIGURE (dB)
OIP3
2800
SSB Noise Figure
vs Supply Voltage
18
–40
–60
–80
–100
2
4
–12 –10 –8 –6 –4 –2 0
RF OUTPUT POWER (dBm/TONE)
–40
–60
–80
85°C
25°C
–40°C
6
5579 G20
14
NOISE FIGURE (dB)
IM2 LEVEL (dBc)
IM3 LEVEL (dBc)
16
12
10
8
6
85°C
25°C
–40°C
–100
2
4
–12 –10 –8 –6 –4 –2 0
RF OUTPUT POWER (dBm/TONE)
85°C
25°C
–40°C
4
6
5579 G21
2
3.0
3.1
3.2
3.4
3.3
SUPPLY VOLTAGE (V)
3.5
3.6
5579 G22
5579fa
LT5579
Typical Performance Characteristics
2140MHz Application:
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)
Conversion Gain and OIP3
vs RF Output Frequency
SSB Noise Figure
vs RF Output Frequency
16
30
12
26
LO-RF Leakage
vs RF Output Frequency
18
0
16
GAIN
4
18
0
–4
1950
12
10
8
6
14
85°C
25°C
–40°C
2
1950
2150
2050
2250
RF FREQUENCY (MHz)
–20
–30
–40
85°C
25°C
–40°C
4
10
2350
2150
2050
2250
RF FREQUENCY (MHz)
LO LEAKAGE (dBm)
GAIN (dB)
22
OIP3 (dBm)
8
–10
14
NOISE FIGURE (dB)
OIP3
–50
1950
2350
85°C
25°C
–40°C
2150
2050
2250
RF FREQUENCY (MHz)
2350
5579 G24
5579 G23
Conversion Gain and OIP3
vs LO Input Power
5579 G25
SSB Noise Figure
vs LO Input Power
16
30
12
26
Conversion Gain and OIP3
vs Supply Voltage
16
18
30
GAIN (dB)
GAIN
4
0
18
–4
–17
–13
–5
–1
–9
LO INPUT POWER (dBm)
12
10
8
6
14
85°C
25°C
–40°C
2
–14
10
–6
–10
–2
LO INPUT POWER (dBm)
2
5579 G26
8
22
GAIN
4
0
85°C
25°C
–40°C
4
3
26
OIP3
–4
18
85°C
25°C
–40°C
3.0
3.1
3.2
3.3
3.4
SUPPLY VOLTAGE (V)
3.5
5579 G27
IM3 Level
vs RF Output Power (2-Tone)
0
–20
–20
14
10
3.6
5579 G19
IM2 Level
vs RF Output Power (2-Tone)
0
OIP3 (dBm)
22
OIP3 (dBm)
8
12
14
GAIN (dB)
OIP3
NOISE FIGURE (dB)
16
SSB Noise Figure
vs Supply Voltage
18
–40
–60
–80
–100
–10
0
–8 –6 –4 –2
2
4
RF OUTPUT POWER (dBm/TONE)
–40
–60
–80
85°C
25°C
–40°C
6
5579 G29
14
NOISE FIGURE (dB)
IM2 LEVEL (dBc)
IM3 LEVEL (dBc)
16
–100
–10
12
10
8
6
85°C
25°C
–40°C
0
–8 –6 –4 –2
2
4
RF OUTPUT POWER (dBm/TONE)
85°C
25°C
–40°C
4
6
5579 G30
2
3.0
3.1
3.2
3.4
3.3
SUPPLY VOLTAGE (V)
3.5
3.6
5579 G31
5579fa
LT5579
Typical Performance Characteristics 1750MHz Application:
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)
Conversion Gain and OIP3
vs RF Output Frequency
SSB Noise Figure
vs RF Output Frequency
16
30
18
OIP3
26
18
0
LO LEAKAGE (dBm)
22
NOISE FIGURE (dB)
GAIN (dB)
GAIN
12
10
8
6
14
1700
2
1650
10
1900
1800
1850
1750
RF FREQUENCY (MHz)
1700
1750
1850
1800
RF FREQUENCY (MHz)
Conversion Gain and OIP3
vs LO Input Power
30
1800
1850
1750
RF FREQUENCY (MHz)
1900
5579 G34
Conversion Gain and OIP3
vs Supply Voltage
16
18
26
32
18
0
10
8
6
14
85°C
25°C
–40°C
–13
–5
–1
–9
LO INPUT POWER (dBm)
12
GAIN (dB)
GAIN
NOISE FIGURE (dB)
22
3
2
–17
10
–13
–9
–1
–5
LO INPUT POWER (dBm)
8
GAIN
4
IM3 Level
vs RF Output Power (2-Tone)
3
–4
3.0
3.1
3.2
3.3
3.4
SUPPLY VOLTAGE (V)
0
–20
–20
12
3.6
3.5
5579 G37
IM2 Level
vs RF Output Power (2-Tone)
0
20
16
5579 G36
5579 G35
24
85°C
25°C
–40°C
0
85°C
25°C
–40°C
4
28
OIP3
OIP3 (dBm)
8
12
14
OIP3 (dBm)
GAIN (dB)
1700
16
OIP3
–4
–17
–50
1650
1900
SSB Noise Figure
vs LO Input Power
16
4
–30
5579 G33
5579 G32
12
–20
–40
85°C
25°C
–40°C
4
–4
1650
85°C
25°C
–40°C
–10
14
OIP3 (dBm)
85°C
25°C
–40°C
4
0
16
12
8
LO-RF Leakage
vs RF Output Frequency
SSB Noise Figure
vs Supply Voltage
18
–40
–60
–80
–100
–10
0
–8 –6 –4 –2
2
4
RF OUTPUT POWER (dBm/TONE)
–40
–60
–80
85°C
25°C
–40°C
6
5579 G38
14
NOISE FIGURE (dB)
IM2 LEVEL (dBc)
IM3 LEVEL (dBc)
16
–100
–10
12
10
8
6
85°C
25°C
–40°C
0
–8 –6 –4 –2
2
4
RF OUTPUT POWER (dBm/TONE)
85°C
25°C
–40°C
4
6
5579 G39
2
3.0
3.1
3.2
3.4
3.3
SUPPLY VOLTAGE (V)
3.5
3.6
5579 G40
5579fa
LT5579
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 capacitors of 1000pF, 100pF and 10pF located as close to the
pins as possible.
RF (Pin 15): Single-Ended RF Output. This pin is connected 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.
5579fa
LT5579
Block Diagram
25
15
EXPOSED
PAD
RF
VCC
22
LO
DOUBLE
BALANCED
MIXER
LO BUFFER
VCC
VCC2
BIAS
VCC2
VCC
10
9
8
VCM
CTRL
IF+
GND PINS ARE NOT SHOWN
VCC
11
3
IF–
4
5579 BD
5579fa
10
LT5579
Test Circuit
LO INPUT
R1
C9
TL2
C3
4
5
C2
6
L2
GND
GND
LO
GND
GND
GND
GND
IF+
GND
GND
IF–
RF
GND
GND
GND
GND
R2
7
8
9
18
17
16
L3
15
14
TL3
RF
OUTPUT
C8
13
GND
IF
INPUT
GND
GND
VCC
3
GND
VCC
2
VCC
TL1
1
L1
VCC
C1
GND
T1
4:1
24 23 22 21 20 19
10 11 12
VCC
C4
C5
C6
C7
5579 F01
REF DES
C1, C2
fRF = 1750MHz
fIF = 240MHz
fRF = 2140MHz
fIF = 240MHz
fRF = 2600MHz
fIF = 456MHz
fRF = 3600MHz
fIF = 456MHz
SIZE
COMMENTS
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
R1, R2
T1
TL1, TL2*
TL3
6.8nH
3.9nH
1nH
0Ω
0402
Toko LL1005-FHL/0Ω Jumper
11Ω, 0.1%
11Ω, 0.1%
11Ω, 0.1%
11Ω, 0.1%
0603
IRC PFC-W0603R-03-11R1-B
4:1
4:1
4:1
4:1
SM-22
—
—
1mm
1.4mm
—
ZO = 70Ω Microstrip
2mm
2mm
2mm
2mm
—
ZO = 70Ω Microstrip
M/A-COM MABAES0061
*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
5579fa
11
LT5579
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 operation in the 1.5GHz to 3.8GHz frequency range, though
operation outside this range is possible with reduced
performance.
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.
IF Input Interface
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.
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 symmetrical and the input resistors should be well matched
(0.1% tolerance is recommended).
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 interactions that can affect the LO to RF leakage performance.
The differential input resistance to the mixer is approximately 10Ω, as indicated in Table 1. The package and
external inductances (TL1 and TL2) are used along with
R1
IF
INPUT
LT5579
T1
4:1
C1
TL1
L1
3
IF+
50mA
570mV
2k
C9
C2
VCC
C3
2k
TL2
4
L2
IF–
570mV
50mA
R2
5579 F02
Figure 2. IF Input with External Matching
5579fa
12
LT5579
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
70
REFLECTION COEFFICIENT
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.)
MAG
ANGLE
8.8+j1.3
0.70
177
140
8.7+j2.3
0.70
175
170
9.0+j2.8
0.70
174
70(3)
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
Table 2. IF Input Component Values
FREQUENCY C1, C2
(MHz)
(pF)
C9
(pF)
C3
(pF)
L1, L2 R1, R2 MATCH BW
(nH)
(Ω) (at 12dB RL)
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
0
RETURN LOSS (dB)
–5
–10
–15
c
–20
a
–25
0
b
100 200 300 400 500 600 700 800
FREQUENCY (MHz)
5579 F03
Figure 3. IF Input Return Loss with 70MHz (a),
240MHz (b) and 456MHz (c) Matching
5579fa
13
LT5579
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 impedance 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.
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
0
VCC
–5
L6
22
LO
C13
VBIAS
5579 F04
Figure 4. LO Input Circuit
RETURN LOSS (dB)
LO
INPUT
EXTERNAL
MATCHING
FOR LOW
FREQUENCY
ONLY
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.
–10
–15
–20
–25
500 1000 1500 2000 2500 3000 3500 4000
FREQUENCY (MHz)
5579 F05
Figure 5. LO Input Return Loss
5579fa
14
LT5579
Applications Information
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 bandwidth 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 bandwidths are listed in Table 5.
Table 4. Single-Ended RF Output Impedance
(at Pin 15, No External Matching)
FREQUENCY
(MHz)
RF OUTPUT
IMPEDANCE
1250
REFLECTION COEFFICIENT
MAG
ANGLE
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
The LT5579 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.
LT5579
0
–5
RETURN LOSS (dB)
DC and RF Grounding
–10
–15
c
–20
L3
15
C8
RF
50Ω
–25
1500
d
a
b
2000
3000
3500
2500
FREQUENCY (MHz)
4000
5579 F07
8
9
10
11
5579 F06
Figure 7. RF Output Return Loss with 1750MHz (a),
2140MHz (b), 2600MHz (c) and 3600MHz (d) Matching
VCC
Figure 6. RF Output Circuit
5579fa
15
LT5579
Typical Applications
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 application. The 4.7nH inductors and the 120pF capacitor
transform the input impedance of the IC up to approximately
9.1Ω
47pF
MABAES0061
1nF
4:1
100nH
LO
4.7nH
6.8nH
120pF
IF
70MHz
4.7nH
1nF
RF
1650MHz
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.
35
OIP3
30
25
20
15
TA = 25°C
fIF = 70MHz
PIF = –5dBm/TONE
PLO = –1dBm
LOW SIDE LO
HIGH SIDE LO
SSB NF
10
5
GAIN
0
1.5pF
47pF
was purposefully shifted high in order to achieve better
OIP3 performance at the desired frequency.
GAIN (dB), NF (dB), OIP3 (dBm)
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.
5579 F08
–5
1550
1650
1600
1700
RF OUTPUT FREQUENCY (MHz)
100nH
9.1Ω
Figure 8. IF Input Tuned for 70MHz
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 application. 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
1750
5579 F09
Figure 9. Gain, Noise Figure and OIP3 vs
RF Frequency with 70MHz IF and 1650MHz RF
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 Figure 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.
5579fa
16
LT5579
TYPICAL APPLICATIONS
OIP3
30
25
20
15
TA = 25°C
fIF = 240MHz
PIF = –5dBm/TONE
PLO = –1dBm
30
SSB NF
10
5
0
1800
LOW SIDE LO
HIGH SIDE LO
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.
GAIN
1850
1900
1950
2000
RF OUTPUT FREQUENCY (MHz)
2050
5579 F10
Figure 10. Gain, Noise Figure and OIP3 vs
RF Frequency for the 1950MHz Application
GAIN (dB), NF (dBm), OIP3 (dBm)
GAIN (dB), NF (dB), OIP3 (dBm)
35
OIP3
25
20
15
TA = 25°C
fIF = 240MHz
PIF = –5dBm/TONE
PLO = –1dBm
fRF = fIF + fLO
5
0
2000
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
SSB NF
10
GAIN
2050 2100 2150 2200 2250
RF OUTPUT FREQUENCY (MHz)
2300
5579 F11
Figure 11. Measured Performance when Tuned
for 240MHz IF, 2140MHz RF and Low Side LO
Figure 12. LT5579 Evaluation Board (DC1233A)
5579fa
17
LT5579
Package Description
UH Package
24-Lead Plastic QFN (5mm × 5mm)
(Reference LTC DWG # 05-08-1747 Rev A)
0.75 p0.05
5.40 p0.05
3.90 p0.05
3.20 p 0.05
3.25 REF
3.20 p 0.05
PACKAGE OUTLINE
0.30 p 0.05
0.65 BSC
RECOMMENDED SOLDER PAD LAYOUT
APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED
5.00 p 0.10
R = 0.05
TYP
0.75 p 0.05
0.00 – 0.05
BOTTOM VIEW—EXPOSED PAD
R = 0.150
TYP
23
PIN 1 NOTCH
R = 0.30 TYP
OR 0.35 s 45o
CHAMFER
24
0.55 p 0.10
PIN 1
TOP MARK
(NOTE 6)
1
2
5.00 p 0.10
3.25 REF
3.20 p 0.10
3.20 p 0.10
(UH24) QFN 0708 REV A
0.200 REF
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
0.30 p 0.05
0.65 BSC
5579fa
18
LT5579
Revision History
REV
DATE
DESCRIPTION
PAGE NUMBER
A
6/10
Revised Typical Application drawing.
1
Revised Absolute Maximum Ratings, Pin Configuration and DC Electrical Characteristics sections.
2
Revised AC Electrical Characteristics section parameters and Note 3.
3
Revised Figure 1 table.
11
Update Tables 2, 3 and 5 in Applications Information section
Added Typical Application drawing and graph, and revised Related Parts list
13, 14, 15
20
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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
19
LT5579
Typical Application
2650MHz LTE Downlink Transmitter
LO INPUT
–1dBm (TYP)
LT5579
Gain and OIP3 vs
RF Output Frequency
LO
10
28
9
27
8
IF
INPUT MABAES0061
33pF
380MHz
4:1
GAIN (dB)
BIAS
11Ω
40nH
IF+
33pF
2.7pF
33pF
RF
1nH
RF
OUTPUT
2650MHz
6
5
4
25
24
TA = 25°C
VCC = 3.3V
fIF = 380MHz
LOW-SIDE LO
HIGH-SIDE LO
22
3
21
2
20
GAIN
1
0
2500
IF–
40nH
11Ω
VCC
1µF
100pF
23
OIP3 (dBm)
GND
26
OIP3
7
19
2550
2600 2650 2700 2750
RF FREQUENCY (MHz)
18
2800
5579 TA02b
5579 TA02a
1nF
VCC
3.3V
Related Parts
PART NUMBER
DESCRIPTION
COMMENTS
400MHz to 3.7GHz, 5V Downconverting Mixer
2.3dB Gain, 23.5dBm IIP3 and 12.5dB NF at 1900MHz, 5V/78mA Supply
Infrastructure
LT5527
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
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
Fixed Gain of 8dB, 14dB, 20dB and 26dB; >36dBm OIP3 at 300MHz, Differential I/O
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
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
ADCs
5579fa
20 Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507 ● www.linear.com
LT 0610 REV A • PRINTED IN USA
 LINEAR TECHNOLOGY CORPORATION 2008