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LT5579 1.5GHz to 3.8GHz High Linearity Upconverting Mixer FEATURES
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DESCRIPTION
The LT(R)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.
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 x 5mm QFN24 Package
APPLICATIONS
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GSM/EDGE, W-CDMA, UMTS, LTE and TD-SCDMA Basestations 2.6GHz and 3.5GHz WiMAX Basestations 2.4GHz ISM Band Transmitters High Performance Transmitters
L, LT, LTC and LTM 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
LT5579 LO
30 GAIN (dB), NF (dB), OIP3 (dBm) 25 20 15 10 5 0 1900 SSB NF TA = 25C VCC = 3.3V fIF = 240MHz fLO = fRF + fIF OIP3
GND 11 IF INPUT 40nH IF+ 33pF 4 82pF IF- RF 1.8nH 0.45pF BIAS
MABAES0061 82pF 4:1 1 5 2 3
RF OUTPUT
GAIN 2000 2100 2200 2300 RF FREQUENCY (MHz) 2400
5579 TA01b
40nH
VCC 1F 100pF
5579 TA01a
11
1nF
VCC 3.3V
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LT5579 ABSOLUTE MAXIMUM RATINGS
(Note 1)
PIN CONFIGURATION
TOP VIEW GND GND GND GND GND 18 GND 17 GND 25 16 GND 15 RF 14 GND 13 GND 7 GND 8 VCC 9 10 11 12 GND VCC VCC VCC LO 24 23 22 21 20 19 GND 1 GND 2 IF+ 3 IF- 4 GND 5 GND 6
Supply Voltage .........................................................3.6V 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 .................................................................... 150C Operating Temperature Range.................. -40C to 85C Storage Temperature Range................... -65C to 150C
UH PACKAGE 24-LEAD (5mm 5mm) PLASTIC QFN TJMAX = 150C, JA = 34C/W EXPOSED PAD (PIN 25) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH LT5579IUH#PBF TAPE AND REEL LT5579IUH#TRPBF PART MARKING 5579 PACKAGE DESCRIPTION 24-Lead (5mm x 5mm) Plastic QFN TEMPERATURE RANGE -40C to 85C 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 Power Supply Requirements (VCC) Supply Voltage Supply Current Input Common Mode Voltage (VCM) CONDITIONS
VCC = 3.3V, TA = 25C (Note 3), unless otherwise noted.
MIN 3.15 TYP 3.3 226 241 570 MAX 3.6 250 UNITS VDC mA mA mV
VCC = 3.3V, PLO = -1dBm VCC = 3.6V, PLO = -1dBm Internally Regulated
AC ELECTRICAL CHARACTERISTICS
PARAMETER IF Input Frequency Range (Note 4) LO Input Frequency Range (Note 4) RF Output Frequency Range (Note 4) CONDITIONS Requires Matching
(Notes 2, 3)
MIN TYP LF to 1000 750 to 4300 900 to 3900 MAX UNITS MHz MHz MHz
Requires Matching Below 1GHz Requires Matching
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LT5579
VCC = 3.3V, TA = 25C, PRF = -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 = 50, External Match ZO = 50, 1100MHz to 4000MHz ZO = 50, External Match MIN TYP 15 >9 >10 -5 to 2 MAX UNITS dB dB dB dBm
AC ELECTRICAL CHARACTERISTICS
VCC = 3.3V, TA = 25C, PRF = -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 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 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 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
Conversion Gain vs Temperature (TA = -40C to 85C) 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
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 to meet specified performance from -40C to 85C 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.
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LT5579 TYPICAL DC PERFORMANCE CHARACTERISTICS
Supply Current vs Supply Voltage
255 245 SUPPLY CURRENT (mA) 235 225 215 205 195 85C 25C -40C 3.0 3.1 3.2 3.3 3.4 SUPPLY VOLTAGE (V) 3.5 3.6
5579 G01
(Test Circuit Shown in Figure 1)
TYPICAL AC PERFORMANCE CHARACTERISTICS
3300MHz to 3800MHz Application: VCC = 3.3V, TA = 25C, 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) SSB Noise Figure Distribution at 3600MHz
30 TA = 90C TA = 25C TA = -45C DISTRIBUTION (%) 25 20 15 10 5 0 19 20 21 23 22 OIP3 (dBm) 24 25 26
5579 G03
Gain Distribution at 3600MHz
25 TA = 90C TA = 25C TA = -45C DISTRIBUTION (%) 16 14 12 10 8 6 4 5 2 0 -2.5 -2.0 -1.5 -1.0 -0.5 0 GAIN (dB) 0 0.5 1.0 1.5
5579 G02
OIP3 Distribution at 3600MHz
20 DISTRIBUTION (%) 15
TA = 90C TA = 25C TA = -45C
10
10
11
12 13 NOISE FIGURE (dB)
14
5579 G04
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LT5579 TYPICAL AC PERFORMANCE CHARACTERISTICS
Conversion Gain and OIP3 vs RF Output Frequency
16 OIP3 28 20 18 24 16 NOISE FIGURE (dB) GAIN (dB) 8 20 14 12 10 8 6 -4 8 3200 3300 3400 3500 3600 3700 3800 3900 RF FREQUENCY (MHz)
5579 G05
3300MHz to 3800MHz Application: VCC = 3.3V, TA = 25C, 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) SSB Noise Figure vs RF Output Frequency
0
LO-RF Leakage vs RF Output Frequency
12
-10 LO LEAKAGE (dBm) 85C 25C -40C
OIP3 (dBm)
4 GAIN 0
85C 25C -40C
-20
16
-30
12
-40
4 3200 3300 3400 3500 3600 3700 3800 3900 RF FREQUENCY (MHz)
5579 G06
85C 25C -40C
-50 3200 3300 3400 3500 3600 3700 3800 3900 RF FREQUENCY (MHz)
5579 G07
Conversion Gain and OIP3 vs LO Input Power
16 26 20 18 12 OIP3 OIP3 (dBm) GAIN (dB) 8 18 22 NOISE FIGURE (dB) 16 14 12 10 8 6 -4 -17 -13 -5 -1 -9 LO INPUT POWER (dBm) 3
5579 G08
SSB Noise Figure vs LO Input Power
16
Conversion Gain and OIP3 vs Supply Voltage
26
12 OIP3
22
OIP3 (dBm)
GAIN (dB)
8
4 GAIN 0
85C 25C -40C
14
4 GAIN
85C 25C -40C
18
14
10
85C 25C -40C -6 -10 -2 LO INPUT POWER (dBm) 2
5579 G09
0
10
6
4 -14
-4
3.0
3.1
3.2 3.3 3.4 SUPPLY VOLTAGE (V)
3.5
6 3.6
5579 G10
IM3 Level vs RF Output Power (2-Tone)
0 0
IM2 Level vs RF Output Power (2-Tone)
20 18
SSB Noise Figure vs Supply Voltage
-20 IM3 LEVEL (dBc) IM2 LEVEL (dBc)
-20 16 NOISE FIGURE (dB) 85C 25C -40C 6 14 12 10 8 6 4 3.0 3.1 3.2 3.4 3.3 SUPPLY VOLTAGE (V) 85C 25C -40C 3.5 3.6
5579 G13
-40
-40
-60
-60
-80
85C 25C -40C 6
-80
-100 2 4 -12 -10 -8 -6 -4 -2 0 RF OUTPUT POWER (dBm/TONE)
-100 2 4 -12 -10 -8 -6 -4 -2 0 RF OUTPUT POWER (dBm/TONE)
5579 G11
5579 G12
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LT5579 TYPICAL AC PERFORMANCE CHARACTERISTICS
Conversion Gain and OIP3 vs RF Output Frequency
16 30 18 16 12 OIP3 OIP3 (dBm) GAIN (dB) 8 GAIN 85C 25C -40C 22 26 NOISE FIGURE (dB) -10 14 12 10 8 6 0 14 4 -4 2200 2300 2400 2500 2600 2700 RF FREQUENCY (MHz) 10 2800 2 2200 2300 2400 85C 25C -40C 2500 2600 2700 RF FREQUENCY (MHz) 2800 LO LEAKAGE (dBm) -20
2300MHz to 2700MHz Application: VCC = 3.3V, TA = 25C, 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) SSB Noise Figure vs RF Output Frequency
0 85C 25C -40C
LO-RF Leakage vs RF Output Frequency
4
18
-30
-40
-50 2200
2300
2400 2500 2600 2700 RF FREQUENCY (MHz)
2800
5579 G14
5579 G15
5579 G16
Conversion Gain and OIP3 vs LO Input Power
16 28 18 16 12 OIP3 85C 25C -40C GAIN 24 NOISE FIGURE (dB) 14 12 10 8 6 4 -4 -17 -13 -5 -1 -9 LO INPUT POWER (dBm) 3
5579 G17
SSB Noise Figure vs LO Input Power
16
Conversion Gain and OIP3 vs Supply Voltage
28 OIP3 85C 25C -40C GAIN
12
24
OIP3 (dBm)
OIP3 (dBm)
GAIN (dB)
GAIN (dB)
8
20
8
20
4
16
4
16
0
12
85C 25C -40C -6 -10 -2 LO INPUT POWER (dBm) 2
5579 G18
0
12
8
2 -14
-4
3.0
3.1
3.4 3.2 3.3 SUPPLY VOLTAGE (V)
3.5
8 3.6
5579 G19
IM3 Level vs RF Output Power (2-Tone)
0 0
IM2 Level vs RF Output Power (2-Tone)
18 16
SSB Noise Figure vs Supply Voltage
-20 IM3 LEVEL (dBc) IM2 LEVEL (dBc)
-20 NOISE FIGURE (dB)
14 12 10 8 6
-40
-40
-60
-60
-80
85C 25C -40C 6
-80
85C 25C -40C 6
4 2 3.0 3.1 3.2 3.4 3.3 SUPPLY VOLTAGE (V)
85C 25C -40C 3.5 3.6
5579 G22
-100 2 4 -12 -10 -8 -6 -4 -2 0 RF OUTPUT POWER (dBm/TONE)
-100 2 4 -12 -10 -8 -6 -4 -2 0 RF OUTPUT POWER (dBm/TONE)
5579 G20
5579 G21
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LT5579 TYPICAL PERFORMANCE CHARACTERISTICS
Conversion Gain and OIP3 vs RF Output Frequency
16 30 18 16 12 NOISE FIGURE (dB) OIP3 26 14 12 10 8 6 0 85C 25C -40C 2150 2250 2050 RF FREQUENCY (MHz) 14 4 2 1950 2150 2050 2250 RF FREQUENCY (MHz) 85C 25C -40C 2350
5579 G24
2140MHz Application: VCC = 3.3V, TA = 25C, 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) SSB Noise Figure vs RF Output Frequency
0
LO-RF Leakage vs RF Output Frequency
-10 LO LEAKAGE (dBm)
OIP3 (dBm)
GAIN (dB)
8 GAIN
22
-20
4
18
-30
-40
85C 25C -40C 2150 2050 2250 RF FREQUENCY (MHz) 2350
5579 G25
-4 1950
10 2350
5579 G23
-50 1950
Conversion Gain and OIP3 vs LO Input Power
16 30 18 16 12 OIP3 26 NOISE FIGURE (dB) 14 12 10 8 6 4 3
5579 G26
SSB Noise Figure vs LO Input Power
16
Conversion Gain and OIP3 vs Supply Voltage
30
12 OIP3
26
OIP3 (dBm)
OIP3 (dBm)
GAIN (dB)
4
GAIN
GAIN (dB)
8
22
8 GAIN
22
18
4
18
0
85C 25C -40C -13 -5 -1 -9 LO INPUT POWER (dBm)
14
85C 25C -40C -6 -10 -2 LO INPUT POWER (dBm) 2
5579 G27
0
85C 25C -40C 3.0 3.1 3.2 3.3 3.4 SUPPLY VOLTAGE (V) 3.5
14
-4 -17
10
2 -14
-4
10 3.6
5579 G19
IM3 Level vs RF Output Power (2-Tone)
0 0
IM2 Level vs RF Output Power (2-Tone)
18 16
SSB Noise Figure vs Supply Voltage
-20 IM3 LEVEL (dBc) -40 IM2 LEVEL (dBc)
-20 -40 NOISE FIGURE (dB)
14 12 10 8 6
-60
-60
-80
85C 25C -40C 0 -8 -6 -4 -2 2 4 RF OUTPUT POWER (dBm/TONE) 6
-80
85C 25C -40C 0 -8 -6 -4 -2 2 4 RF OUTPUT POWER (dBm/TONE) 6
4 2 3.0 3.1 3.2 3.4 3.3 SUPPLY VOLTAGE (V)
85C 25C -40C 3.5 3.6
5579 G31
-100 -10
-100 -10
5579 G29
5579 G30
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LT5579 TYPICAL PERFORMANCE CHARACTERISTICS 1750MHz Application:
VCC = 3.3V, TA = 25C, 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
16 OIP3 12 85C 25C -40C GAIN 26 NOISE FIGURE (dB) 30 18 16 14 12 10 8 6 4 -4 1650 1700 1800 1850 1750 RF FREQUENCY (MHz) 10 1900
5579 G32
SSB Noise Figure vs RF Output Frequency
0
LO-RF Leakage vs RF Output Frequency
85C 25C -40C
-10 LO LEAKAGE (dBm) 85C 25C -40C 1700 1850 1800 RF FREQUENCY (MHz) 1750 1900
5579 G33
OIP3 (dBm)
GAIN (dB)
8
22
-20
4
18
-30
0
14
-40
2 1650
-50 1650
1700
1800 1850 1750 RF FREQUENCY (MHz)
1900
5579 G34
Conversion Gain and OIP3 vs LO Input Power
16 OIP3 30 18 16 26 NOISE FIGURE (dB) 14
SSB Noise Figure vs LO Input Power
16
Conversion Gain and OIP3 vs Supply Voltage
32
12
12
OIP3
28
GAIN (dB)
GAIN (dB)
8 GAIN
22
12 10 8 6
OIP3 (dBm)
OIP3 (dBm)
8 GAIN
4
18
4
85C 25C -40C
24
20
0
-4 -17
85C 25C -40C -13 -5 -1 -9 LO INPUT POWER (dBm) 3
5579 G35
14 4 10 2 -17 -13 -1 -5 LO INPUT POWER (dBm) -9
85C 25C -40C 3
5579 G36
0
16
-4
3.0
3.1
3.2 3.3 3.4 SUPPLY VOLTAGE (V)
3.5
12 3.6
5579 G37
IM3 Level vs RF Output Power (2-Tone)
0 0
IM2 Level vs RF Output Power (2-Tone)
18 16
SSB Noise Figure vs Supply Voltage
-20 IM3 LEVEL (dBc) IM2 LEVEL (dBc) -40
-20 NOISE FIGURE (dB) -40
14 12 10 8 6
-60
-60
-80
85C 25C -40C 0 -8 -6 -4 -2 2 4 RF OUTPUT POWER (dBm/TONE) 6
-80
85C 25C -40C 0 -8 -6 -4 -2 2 4 RF OUTPUT POWER (dBm/TONE) 6
4 2 3.0 3.1 3.2 3.4 3.3 SUPPLY VOLTAGE (V)
85C 25C -40C 3.5 3.6
5579 G40
-100 -10
-100 -10
5579 G38
5579 G39
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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.
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LT5579 BLOCK DIAGRAM
25 EXPOSED PAD 15 RF
VCC LO LO BUFFER VCC VCC2 VCC VCC
11
22
DOUBLE BALANCED MIXER
10
9
BIAS
8
VCC2
VCM CTRL IF+ 3 4 IF-
5579 BD
GND PINS ARE NOT SHOWN
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LT5579 TEST CIRCUIT
LO INPUT
R1 1 2 3 C9 TL2 C3 4 5 C2 L2 6
24 23 22 21 20 19 GND GND GND GND GND LO GND GND IF+ IF- GND GND GND VCC VCC VCC VCC GND GND GND GND RF GND GND GND 18 17 16 15 14 13 C8 L3 TL3 RF OUTPUT
T1 4:1 IF INPUT
C1
L1 TL1
R2
7
8
9
10 11 12 VCC
C4
C5
C6
C7
5579 F01
REF DES C1, C2 C3 C4 C5 C6 C7 C8 C9 L1, L2 L3 R1, R2 T1 TL1, TL2* TL3
fRF = 1750MHz fIF = 240MHz 82pF -- 100pF 10pF 1nF 1F 1.2pF 33pF 40nH 6.8nH 11, 0.1% 4:1 -- 2.3mm
fRF = 2140MHz fIF = 240MHz 82pF -- 100pF 10pF 1nF 1F 0.45pF 33pF 40nH 1.8nH 11, 0.1% 4:1 -- 2.3mm
fRF = 2600MHz fIF = 456MHz 33pF 2.7pF 100pF 10pF 1nF 1F -- 33pF 40nH 1nH 11, 0.1% 4:1 1.3mm 2.3mm
fRF = 3600MHz fIF = 456MHz 33pF 1.8pF 100pF 10pF 1nF 1F 0.7pF 33pF 40nH 0 11, 0.1% 4:1 1.9mm 2.3mm
SIZE 0402 0402 0402 0603 0402 0603 0402 0402 0402 0402 0603 SM-22 -- --
COMMENTS AVX AVX AVX AVX AVX Taiyo Yuden LMK107BJ105MA AVX ACCU-P AVX Coilcraft 0402CS Toko LL1005-FHL/0 Jumper IRC PFC-W0603R-03-11R1-B M/A-COM MABAES0061 ZO = 70 Microstrip ZO = 70 Microstrip
*Center-to-center spacing between C9 and C3. Center of C9 is 3.0mm from the edge of the IC package for all cases.
Figure 1. Test Circuit Schematic
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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. 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 symmetrical 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 interactions that can affect the LO to RF leakage performance. The differential input resistance to the mixer is approximately 10, 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 L1 TL1 3 IF+ 570mV 2k C9 C2 TL2 4 L2 C3 IF- 570mV 50mA
5579 F02
50mA
VCC 2k
R2
Figure 2. IF Input with External Matching
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LT5579 APPLICATIONS INFORMATION
C9 to step the impedance up to about 12.5. 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) 70 140 170 190 240 380 450 750 1000 IF INPUT IMPEDANCE 8.8+j1.3 8.7+j2.3 9.0+j2.8 8.9+j3.0 9.0+j4.0 9.7+j4.9 10.0+j5.2 10.8+j9.4 11.8+j13.8 REFLECTION COEFFICIENT MAG 0.70 0.70 0.70 0.70 0.70 0.68 0.67 0.65 0.64 ANGLE 177 175 174 173 170 168 167 158 148
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 C1, C2 (MHz) (pF) 140 240 450 1000 82 33 C9 (pF) 120 33 33 C3 (pF) (1) (1) (1) L1, L2 R1, R2 MATCH BW (nH) () (at 12dB RL) 100 40 40 9.1 11 11 <50 to 158 174 to 263 330 to 505
Note: (1) Depends on RF (2) T1 = M/A-Com MABAES0061 ,
0
-5 RETURN LOSS (dB) -10
-15 c -20 a -25 0 100 200 300 400 500 600 700 800 FREQUENCY (MHz)
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b
Figure 3. IF Input Return Loss with 70MHz (a), 240MHz (b) and 456MHz (c) Matching
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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.
EXTERNAL MATCHING FOR LOW FREQUENCY ONLY L6 22 C13 VBIAS
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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) 750 1000 1500 1900 2000 2150 2400 3050 3150 4000 INPUT IMPEDANCE 63.3||- j30.5 20.3||- j1120 78.4||- j1250 79.1||- j113 74.7||- j96.3 66.8||- j81.5 53.8||- j69.8 33.7||- j115 33.0||- j146 43.9||+ j173 REFLECTION COEFFICIENT MAG 0.68 0.42 0.22 0.34 0.35 0.36 0.35 0.26 0.24 0.15 ANGLE -125 -179 -7.7 -65.2 -74.7 -87.0 -105 -148 -154 -123
0 VCC -5 RETURN LOSS (dB) LO
LO INPUT
-10
-15
Figure 4. LO Input Circuit
-20
-25 500 1000 1500 2000 2500 3000 3500 4000 FREQUENCY (MHz)
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Figure 5. LO Input Return Loss
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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. DC and RF Grounding 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 RF 50 0
Table 4. Single-Ended RF Output Impedance (at Pin 15, No External Matching)
FREQUENCY (MHz) 1250 1750 1950 2150 2300 2600 3600 RF OUTPUT IMPEDANCE 11.0+j42.7 55.6+j83.4 119+j62.4 116-j21.0 73.7-j37.7 35.2-j21.5 21.9+j17.8 REFLECTION COEFFICIENT MAG 0.78 0.62 0.52 0.42 0.34 0.30 0.45 ANGLE 97.4 47.8 21.9 -10.4 -40.9 -110 134
Table 5. RF Output Component Values
FREQUENCY (MHz) 1650 1750 1950 2140 2600 3600 C8 (pF) 1.5 1.2 1 0.45 0.45 0.7 L3 (nH) 6.8 6.8 4.7 3.9 1.8 0 MATCH BW (at 12dB RL) 1630 to 1770 1725 to 1870 1840 to 2020 2035 to 2285 2260 to 2780* 3170 to 4100*
*10dB Return Loss bandwidth
-5 RETURN LOSS (dB)
-10
-15 c -20 d a -25 1500 2000 b 3000 3500 2500 FREQUENCY (MHz) 4000
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L3 15 C8
8
9
10
11 VCC
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Figure 7. RF Output Return Loss with 1750MHz (a), 2140MHz (b), 2600MHz (c) and 3600MHz (d) Matching
Figure 6. RF Output Circuit
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15
LT5579 TYPICAL APPLICATIONS
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 application. The 4.7nH inductors and the 120pF capacitor transform the input impedance of the IC up to approximately
9.1 100nH
12.5. 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.
47pF MABAES0061 1nF 4:1 IF 70MHz 120pF
LO
4.7nH 6.8nH 4.7nH 1.5pF 47pF
RF 1650MHz
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1nF
100nH 9.1
Figure 8. IF Input Tuned for 70MHz
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16
LT5579 TYPICAL APPLICATIONS
The RF port impedance match was realized with C8 = 1.5pF and L3 = 6.8nH. The optimum impedance match 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.
35 GAIN (dB), NF (dB), OIP3 (dBm) 30 25 20 15 10 5 GAIN 0 -5 1550 1650 1600 1700 RF OUTPUT FREQUENCY (MHz) 1750
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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.
35 GAIN (dB), NF (dB), OIP3 (dBm) 30 25 20 15 10 5 GAIN 0 1800 1850 1900 1950 2000 RF OUTPUT FREQUENCY (MHz) 2050
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OIP3
OIP3
TA = 25C fIF = 70MHz PIF = -5dBm/TONE PLO = -1dBm SSB NF
LOW SIDE LO HIGH SIDE LO
TA = 25C fIF = 240MHz PIF = -5dBm/TONE PLO = -1dBm SSB NF
LOW SIDE LO HIGH SIDE LO
Figure 9. Gain, Noise Figure and OIP3 vs RF Frequency with 70MHz IF and 1650MHz RF
Figure 10. Gain, Noise Figure and OIP3 vs RF Frequency for the 1950MHz Application
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17
LT5579 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 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 (dB), NF (dBm), OIP3 (dBm) 30 25 20 15 10 5 0 2000 OIP3 TA = 25C fIF = 240MHz PIF = -5dBm/TONE PLO = -1dBm fRF = fIF + fLO SSB NF
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)
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18
LT5579 PACKAGE DESCRIPTION
UH Package 24-Lead Plastic QFN (5mm x 5mm)
(Reference LTC DWG # 05-08-1747 Rev O)
0.75 0.05
5.40 0.05 3.90 0.05 3.25 REF 3.20 0.05
3.20 0.05
PACKAGE OUTLINE
0.30 0.05 0.65 BSC RECOMMENDED SOLDER PAD LAYOUT APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 5.00 0.10 0.75 0.05 0.00 - 0.05 PIN 1 TOP MARK (NOTE 6) R = 0.05 TYP BOTTOM VIEW--EXPOSED PAD R = 0.115 TYP PIN 1 NOTCH R = 0.30 TYP OR 0.35 45 CHAMFER
23
24 0.55 0.10 1 2
3.20 0.10 5.00 0.10 3.25 REF
3.20 0.10
(UH24) QFN 1206 REV O
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 0.05 0.65 BSC
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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 RELATED PARTS
PART NUMBER Infrastructure LT5514 LT5517 LT5518 LT5519 LT5520 LT5521 LT5522 LT5524 LT5525 LT5526 LT5527 LT5528 DESCRIPTION Ultralow Distortion, IF Amplifier/ADC Driver with Digitally Controlled Gain 40MHz to 900MHz Quadrature Demodulator 1.5GHz to 2.4GHz High Linearity Direct Quadrature Modulator 0.7GHz to 1.4GHz High Linearity Upconverting Mixer 1.3GHz to 2.3GHz High Linearity Upconverting Mixer 10MHz to 3700MHz High Linearity Upconverting Mixer 400MHz to 2.7GHz High Signal Level Downconverting Mixer Low Power, Low Distortion ADC Driver with Digitally Programmable Gain High Linearity, Low Power Downconverting Mixer High Linearity, Low Power Downconverting Mixer 400MHz to 3.7GHz High Signal Level Downconverting Mixer 1.5GHz to 2.4GHz High Linearity Direct Quadrature Modulator COMMENTS 850MHz Bandwidth, 47dBm OIP3 at 100MHz, 10.5dB to 33dB Gain Control Range 21dBm IIP3, Integrated LO Quadrature Generator 22.8dBm OIP3 at 2GHz, -158.2dBm/Hz Noise Floor, 50 Single-Ended RF and LO Ports, 4-Channel W-CDMA ACPR = -64dBc at 2.14GHz 17.1dBm IIP3 at 1GHz, Integrated RF Output Transformer with 50 Matching, Single-Ended LO and RF Ports Operation 15.9dBm IIP3 at 1.9GHz, Integrated RF Output Transformer with 50 Matching, Single-Ended LO and RF Ports Operation 24.2dBm IIP3 at 1.95GHz, NF = 12.5dB, 3.15V to 5.25V Supply, Single-Ended LO Port Operation 4.5V to 5.25V Supply, 25dBm IIP3 at 900MHz, NF = 12.5dB, 50 Single-Ended RF and LO Ports 450MHz Bandwidth, 40dBm OIP3, 4.5dB to 27dB Gain Control Single-Ended 50 RF and LO Ports, 17.6dBm IIP3 at 1900MHz, ICC = 28mA 3V to 5.3V Supply, 16.5dBm IIP3, 100kHz to 2GHz RF NF = 11dB, ICC = 28mA, , -65dBm LO-RF Leakage IIP3 = 23.5dBm and NF = 12.5dBm at 1900MHz, 4.5V to 5.25V Supply, ICC = 78mA, Conversion Gain = 2dB
21.8dBm OIP3 at 2GHz, -159.3dBm/Hz Noise Floor, 50, 0.5VDC Baseband Interface, 4-Channel W-CDMA ACPR = -66dBc at 2.14GHz LT5557 400MHz to 3.8GHz 3.3V Downconverting Mixer IIP3 = 23.5dBm at 3.6GHz, NF = 15.4dB, Conversion Gain = 1.7dB, 3.3V Supply at 82mA, Single-Ended RF and LO Inputs LT5558 600MHz to 1100MHz High Linearity Direct 22.4dBm OIP3 at 900MHz, -158dBm/Hz Noise Floor, 3k, 2.1VDC Baseband Quadrature Modulator Interface, 3-Ch CDMA2000 ACPR = -70.4dBc at 900MHz LT5560 Ultra-Low Power Active Mixer 10mA Supply Current, 10dBm IIP3, 10dB NF Usable as Up- or Down-Converter. , LT5568 700MHz to 1050MHz High Linearity Direct 22.9dBm OIP3 at 850MHz, -160.3dBm/Hz Noise Floor, 50, 0.5VDC Baseband Quadrature Modulator Interface, 3-Ch CDMA2000 ACPR = -71.4dBc at 850MHz LT5572 1.5GHz to 2.5GHz High Linearity Direct 21.6dBm OIP3 at 2GHz, -158.6dBm/Hz Noise Floor, High-Ohmic 0.5VDC Baseband Quadrature Modulator Interface, 4-Ch W-CDMA ACPR = -67.7dBc at 2.14GHz LT5575 700MHz to 2.7GHz Direct Conversion I/Q Integrated Baluns, 28dBm IIP3, 13dBm P1dB, 0.03dB I/Q Amplitude Match, Demodulator 0.4 Phase Match RF Power Detectors LTC(R)5505 RF Power Detectors with >40dB Dynamic Range 300MHz to 3GHz, Temperature Compensated, 2.7V to 6V Supply LTC5507 100kHz to 1000MHz RF Power Detector 100kHz to 1GHz, Temperature Compensated, 2.7V to 6V Supply LTC5508 300MHz to 7GHz RF Power Detector 44dB Dynamic Range, Temperature Compensated, SC70 Package LTC5509 300MHz to 3GHz RF Power Detector 36dB Dynamic Range, Low Power Consumption, SC70 Package LTC5530 300MHz to 7GHz Precision RF Power Detector Precision VOUT Offset Control, Shutdown, Adjustable Gain LTC5531 300MHz to 7GHz Precision RF Power Detector Precision VOUT Offset Control, Shutdown, Adjustable Offset LTC5532 300MHz to 7GHz Precision RF Power Detector Precision VOUT Offset Control, Adjustable Gain and Offset LT5534 50MHz to 3GHz Log RF Power Detector with 1dB Output Variation over Temperature, 38ns Response Time, Log Linear 60dB Dynamic Range Response LTC5536 Precision 600MHz to 7GHz RF Power Detector 25ns Response Time, Comparator Reference Input, Latch Enable Input, with Fast Comparator Output -26dBm to +12dBm Input Range 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, Fast 500ns Rise Time
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20 Linear Technology Corporation
(408) 432-1900
LT 0108 * PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
FAX: (408) 434-0507 www.linear.com
(c) LINEAR TECHNOLOGY CORPORATION 2008

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