View LT5578_229447.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

www..com
LT5578 0.4GHz to 2.7GHz High Linearity Upconverting Mixer DESCRIPTION
The LT(R)5578 mixer is a high performance upconverting mixer optimized for frequencies in the 0.4GHz to 2.7GHz 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 1.95GHz operation, the LT5578 provides conversion gain of -0.7dB, high OIP3 of 24.3dBm and a low noise floor of -158dBm/Hz at a -5dBm RF output signal level. The LT5578 offers a high performance alternative to passive mixers. Unlike passive mixers, which have conversion loss and require high LO drive levels, the LT5578 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.
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.
FEATURES
n n n n n n n n n
High Output IP3: 27dBm at 0.9GHz 24.3dBm at 1.95GHz Low Noise Floor: -158dBm/Hz (POUT = -5dBm) High Conversion Gain: 1.4dB at 0.9GHz Noise Figure: 8.6dB Low LO-RF Leakage: -43dBm Single-Ended RF and LO Ports Low LO Drive Level: -1dBm Single 3.3V Supply 5mm x 5mm QFN24 Package (Pin Compatible with LT5579)
APPLICATIONS
n n n n
GSM 900PCS/1800PCS and W-CDMA Infrastructure LTE and WiMAX Basestations Wireless Repeaters Public Safety Radios
TYPICAL APPLICATION
Frequency Upconversion in LTE Transmitter
LO INPUT -1dBm 2.7pF 6.8pF 30 LT5578 LO GND 13.7 IF 140MHz 100nH IF+ 39pF IF- RF 22nH 2pF BIAS RF 700MHz 13nH TO 950MHz 2.7pF GAIN (dB), NF (dB), OIP3 (dBm) 25 20 15 10 5 GAIN 100nH VCC 10F 100F
5579 TA01a
Gain, NF and OIP3 vs RF Output Frequency
OIP3
TC4-1W+ 220pF 4:1
TA = 25C fIF = 140MHz fLO = fRF - fIF
SSB NF
220pF
13.7
1nF
VCC 3.3V
0 650 700 750 800 850 900 950 1000 RF OUTPUT FREQUENCY (MHz)
5578 TA01b
5578f
1
www..com
LT5578
(Note 1)
ABSOLUTE MAXIMUM RATINGS
Supply Voltage ............................................................4V LO Input Power ....................................................10dBm LO Input DC Current ..............................................30mA RF Output DC Current ............................................45mA IF Input Power (Differential).................................18dBm IF+, IF- DC Currents ...............................................45mA TJMAX .................................................................... 150C Operating Temperature Range.................. -40C to 85C Storage Temperature Range................... -65C to 150C
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
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 LT5578IUH#PBF TAPE AND REEL LT5578IUH#TRPBF PART MARKING 5578 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 3.1 TYP 3.3 152 159 565 MAX 3.5 170 UNITS VDC mA mA mV
VCC = 3.3V, PLO = -1dBm VCC = 3.5V, 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 600 400 to 3000 400 to 2700 MAX UNITS MHz MHz MHz
Requires Matching Below 1.5GHz Requires Matching
5578f
2
www..com
LT5578
CONDITIONS ZO = 50, External Match ZO = 50, External Match 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, 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
VCC = 3.3V, TA = 25C, PIF = -5dBm (-5dBm/tone for 2-tone tests, f = 1MHz), PLO = -1dBm, unless otherwise noted. Low side LO for 900MHz. High side LO for 740MHz and 1950MHz. (Notes 2, 3, 4)
PARAMETER Conversion Gain CONDITIONS fRF = 740MHz, fIF = 140MHz fRF = 900MHz, fIF = 140MHz fRF = 1950MHz, fIF = 240MHz fRF = 740MHz, fIF = 140MHz fRF = 900MHz, fIF = 140MHz fRF = 1950MHz, fIF = 240MHz fRF = 740MHz, fIF = 140MHz fRF = 900MHz, fIF = 140MHz fRF = 1950MHz, fIF = 240MHz fRF = 740MHz, fIF = 140MHz fRF = 900MHz, fIF = 140MHz fRF = 1950MHz, fIF = 240MHz fRF = 740MHz, fIF = 140MHz fRF = 900MHz, fIF = 140MHz fRF = 1950MHz, fIF = 240MHz fRF = 740MHz, fIF = 140MHz fRF = 900MHz, fIF = 140MHz fRF = 1950MHz, fIF = 240MHz fRF = 740MHz, fIF = 140MHz fRF = 900MHz, fIF = 140MHz fRF = 1950MHz, fIF = 240MHz fRF = 740MHz, fIF = 140MHz fRF = 900MHz, fIF = 140MHz fRF = 1950MHz, fIF = 240MHz fRF = 740MHz, fIF = 140MHz fRF = 900MHz, fIF = 140MHz fRF = 1950MHz, fIF = 240MHz fRF = 740MHz, fIF = 140MHz fRF = 900MHz, fIF = 140MHz fRF = 1950MHz, fIF = 240MHz fRF = 740MHz, fIF = 140MHz fRF = 900MHz, fIF = 140MHz fRF = 1950MHz, fIF = 240MHz fRF = 740MHz, fIF = 140MHz fRF = 900MHz, fIF = 140MHz fRF = 1950MHz, fIF = 240MHz MIN TYP 0.8 1.4 -0.7 -0.020 -0.018 -0.021 26.5 27.0 24.3 62 52 58 8.6 8.6 10.5 -161 -160.5 -158 -158 -157.5 -154 -154 -153 -149.5 11.6 12 10 80 75 60 -31 -40 -22 -43 -43 -46 MAX UNITS dB dB dB dB/C dB/C dB/C dBm dBm dBm dBm dBm dBm dB dB dB dBm/Hz dBm/Hz dBm/Hz dBm/Hz dBm/Hz dBm/Hz dBm/Hz dBm/Hz dBm/Hz dBm dBm dBm dB dB dB dBm dBm dBm dBm dBm dBm
Conversion Gain vs Temperature (TA = -40C to 85C) Output 3rd Order Intercept
Output 2nd Order Intercept (LO 2IF)
Single Sideband Noise Figure
Output Noise: POUT = -5dBm Output Noise: POUT = 0dBm Output Noise: 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 LT5578 is guaranteed functional over the operating temperature range 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.
5578f
3
www..com
LT5578
TYPICAL DC PERFORMANCE CHARACTERISTICS
Supply Current vs Supply Voltage
180 170 SUPPLY CURRENT (mA) 160 150 140 130 120 85C 25C -40C 3.0 3.1 3.2 3.3 3.4 SUPPLY VOLTAGE (V) 3.5 3.6
5578 G01
(Test Circuit Shown in Figure 1)
TYPICAL AC PERFORMANCE CHARACTERISTICS
900MHz Application: VCC = 3.3V, TA = 25C, fIF = 140MHz, PIF = -5dBm (-5dBm/tone for 2-tone tests, f = 1MHz), low side LO, PLO = -1dBm, output measured at 900MHz, unless otherwise noted. (Test circuit shown in Figure 1) SSB Noise Figure Distribution at 900MHz
60 50 DISTRIBUTION (%) 40 30 20 10 0 6 7 8 9 NOISE FIGURE (dB) 10 11
5578 G04
Gain Distribution at 900MHz
45 40 35 DISTRIBUTION (%) 30 25 20 15 10 5 0 -0.5 0 0.5 1.0 1.5 2.0 GAIN (dB) 2.5 3.0 3.5
5578 G02
OIP3 Distribution at 900MHz
25 TA = 90C TA = 25C TA = -45C
TA = 90C TA = 25C TA = -45C DISTRIBUTION (%)
20
TA = 90C TA = 25C TA = -45C
15
10
5
0
23
24
25
26 27 OIP3 (dBm)
28
29
5578 G03
5578f
4
www..com
LT5578
TYPICAL AC PERFORMANCE CHARACTERISTICS
Conversion Gain and OIP3 vs RF Output Frequency
16 OIP3 12 26 30 18 16
740MHz Application: VCC = 3.3V, TA = 25C, fIF = 140MHz, PIF = -5dBm (-5dBm/tone for 2-tone tests, f = 1MHz), high side LO, PLO = -1dBm, output measured at 740MHz, unless otherwise noted. (Test circuit shown in Figure 1) SSB Noise Figure vs RF Output Frequency
0 -10 LO LEAKAGE (dBm) 85C 25C -40C 700 720 740 760 RF FREQUENCY (MHz) 780 800 -20 -30 -40 -50 -60 660 85C 25C -40C 680 700 720 740 760 RF FREQUENCY (MHz) 780 800
LO-RF Leakage vs RF Output Frequency
NOISE FIGURE (dB)
14 12 10 8 6 4
OIP3 (dBm)
GAIN (dB)
8
4 GAIN 0
85C 25C -40C
22
18
14
-4 660
680
700 720 740 760 RF FREQUENCY (MHz)
780
10 800
2 660 680
5578 G05
5578 G06
5578 G07
Conversion Gain and OIP3 vs LO Input Power
16 OIP3 16 12 26 14 NOISE FIGURE (dB) 12 10 8 6 4 -4 -17 10 -13 -5 -1 -9 LO INPUT POWER (dBm) 3
5578 G08
SSB Noise Figure vs LO Input Power
30 18 16
Conversion Gain and OIP3 vs Supply Voltage
30 OIP3 12 26
OIP3 (dBm)
OIP3 (dBm)
GAIN (dB)
4
85C 25C -40C GAIN
GAIN (dB)
8
22
8
22 85C 25C -40C GAIN
18
4
18
0
14
2 -17
85C 25C -40C -9 -13 -5 -1 LO INPUT POWER (dBm) 3
5578 G09
0
14
-4
3.0
3.1
3.2 3.3 3.4 SUPPLY VOLTAGE (V)
10 3.5
5578 G10
IM3 Level vs RF Output Power (2-Tone)
0 0
IM2 Level vs RF Output Power (1-Tone)
18 16
SSB Noise Figure vs Supply Voltage
-20 IM3 LEVEL (dBc) IM2 LEVEL (dBc)
-20 NOISE FIGURE (dB) 85C 25C -40C 4 6
14 12 10 8 6
-40
-40
-60
-60
-80
85C 25C -40C 6
-80
4 2 3.0 3.1 3.4 3.2 3.3 SUPPLY VOLTAGE (V)
85C 25C -40C 3.5
5578 G13
-100 2 4 -12 -10 -8 -6 -4 -2 0 RF OUTPUT POWER (dBm/TONE)
-100 2 -12 -10 -8 -6 -4 -2 0 RF OUTPUT POWER (dBm)
5578 G11
5578 G12
5578f
5
www..com
LT5578
TYPICAL AC PERFORMANCE CHARACTERISTICS
Conversion Gain and OIP3 vs RF Output Frequency
16 OIP3 16 12 26 14 NOISE FIGURE (dB) 30 18
900MHz Application: VCC = 3.3V, TA = 25C, fIF = 140MHz, PIF = -5dBm (-5dBm/tone for 2-tone tests, f = 1MHz), low side LO, PLO = -1dBm, output measured at 900MHz, unless otherwise noted. (Test circuit shown in Figure 1) SSB Noise Figure vs RF Output Frequency
0 -10 LO LEAKAGE (dBm) 85C 25C -40C 850 870 890 910 930 RF FREQUENCY (MHz) 950 970 -20 -30 -40 -50 -60 830 85C 25C -40C 850 870 890 910 930 RF FREQUENCY (MHz) 950 970
LO-RF Leakage vs RF Output Frequency
GAIN (dB)
8
4
85C 25C -40C GAIN
22
12 10 8 6 4
OIP3 (dBm)
18
0
14
-4 830
850
870 890 910 930 RF FREQUENCY (MHz)
950
10 970
2 830
5578 G14
5578 G15
5578 G16
Conversion Gain and OIP3 vs LO Input Power
16 OIP3 16 12 85C 25C -40C GAIN 26 NOISE FIGURE (dB) 14 12 10 8 6 4 -4 -17 -13 -5 -1 -9 LO INPUT POWER (dBm) 3
5578 G17
SSB Noise Figure vs LO Input Power
30 18 16
Conversion Gain and OIP3 vs Supply Voltage
30 OIP3 12 26
OIP3 (dBm)
OIP3 (dBm)
GAIN (dB)
GAIN (dB)
8
22
8
85C 25C -40C GAIN
22
4
18
4
18
0
14
85C 25C -40C -9 -1 -13 -5 LO INPUT POWER (dBm) 3
5578 G18
0
14
10
2 -17
-4
3.0
3.1
3.2 3.3 3.4 SUPPLY VOLTAGE (V)
10 3.5
5578 G19
IM3 Level vs RF Output Power (2-Tone)
0 0
IM2 Level vs RF Output Power (1-Tone)
18 16
SSB Noise Figure vs Supply Voltage
-20 IM3 LEVEL (dBc) IM2 LEVEL (dBc)
-20 14 NOISE FIGURE (dB) 85C 25C -40C 4 6 12 10 8 6 4 2 3.0 3.1 3.2 3.4 3.3 SUPPLY VOLTAGE (V) 85C 25C -40C 3.5
5578 G22
-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 -12 -10 -8 -6 -4 -2 0 RF OUTPUT POWER (dBm)
5578 G20
5578 G21
5578f
6
www..com
LT5578
TYPICAL PERFORMANCE CHARACTERISTICS
Conversion Gain and OIP3 vs RF Output Frequency
16 OIP3 28 18 16 12 24 NOISE FIGURE (dB) 14
1950MHz 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 1950MHz, unless otherwise noted. (Test circuit shown in Figure 1) SSB Noise Figure vs RF Output Frequency
0 -10 LO LEAKAGE (dBm) 85C 25C -40C 1700 1800 1900 2000 2100 RF FREQUENCY (MHz) 2200 -20 -30 -40 -50 85C 25C -40C
LO-RF Leakage vs RF Output Frequency
GAIN (dB)
8
4 GAIN 0
85C 25C -40C
20
12 10 8 6 4
OIP3 (dBm)
16
12
-4 1600
1700
1800 1900 2000 2100 RF FREQUENCY (MHz)
8 2200
2 1600
-60 1600 1700 1800 1900 2000 2100 2200 2300 RF FREQUENCY (MHz)
5578 G25
5578 G23
5578 G24
Conversion Gain and OIP3 vs LO Input Power
16 OIP3 12 24 NOISE FIGURE (dB) 14 12 10 8 6 4 -4 -17 -13 -5 -1 -9 LO INPUT POWER (dBm) 3
5578 G26
SSB Noise Figure vs LO Input Power
28 18 16 12 16
Conversion Gain and OIP3 vs Supply Voltage
28 OIP3 24
OIP3 (dBm)
OIP3 (dBm)
GAIN (dB)
4 GAIN 0
85C 25C -40C
GAIN (dB)
8
20
8
16
4 GAIN
85C 25C -40C
20
16
12
85C 25C -40C -9 -1 -13 -5 LO INPUT POWER (dBm) 3
5578 G27
0
12
8
2 -17
-4
3.0
3.1
3.2 3.3 3.4 SUPPLY VOLTAGE (V)
8 3.5
5578 G28
IM3 Level vs RF Output Power (2-Tone)
0 0
IM2 Level vs RF Output Power (1-Tone)
18 16
SSB Noise Figure vs Supply Voltage
-20 IM3 LEVEL (dBc) -40 IM2 LEVEL (dBc)
-20 NOISE FIGURE (dB) -40
14 12 10 8 6
-60
-60
-80
85C 25C -40C 4
-80
-100 2 -14 -12 -10 -8 -6 -4 -2 0 RF OUTPUT POWER (dBm/TONE)
85C 25C -40C 2 4
4 2 3.0 3.1 3.2 3.4 3.3 SUPPLY VOLTAGE (V)
85C 25C -40C 3.5
5578 G31
-100 -14 -12 -10 -8 -6 -4 -2 0 RF OUTPUT POWER (dBm)
5578 G29
5578 G30
5578f
7
www..com
LT5578
PIN FUNCTIONS
GND (Pins 1, 2, 5-7, 12-14, 16-21, 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 565mV. 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 45mA. VCC (Pins 8-11): Power Supply Pins for the IC. These pins are connected together internally. Typical current consumption is 152mA. 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.
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-
5578 BD
GND PINS ARE NOT SHOWN
5578f
8
www..com
LT5578
LO INPUT
TEST CIRCUIT
C13 Z1 C12
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 C14 RF OUTPUT
T1 4:1 IF INPUT
C1
L1 TL1
R2
7
8
9
10 11 12 VCC
C4
C5
C6
C7
5578 F01
REF DES C1, C2 C3 C4 C5 C6 C7 C8 C9 C12 C13 C14 L1, L2 L3 R1, R2 T1 TL1, TL2* TL3 Z1
fRF = 740MHz fIF = 140MHz fLO = 880MHz 220pF - 100pF 10pF 1nF 1F 3.3pF 39pF - - - 100nH 18nH 13.7, 0.1% 4:1 - 2.3mm 2.6pF
fRF = 900MHz fIF = 140MHz fLO = 760MHz 220pF - 100pF 10pF 1nF 1F 1.8pF 39pF - 2.7pF - 100nH 12nH 13.7, 0.1% 4:1 - 2.3mm 6.8pF
fRF = 1950MHz fIF = 240MHz fLO = 2190MHz 82pF 4.7pF 100pF 10pF 1nF 1F - 33pF - - 1.2pF 100nH 1.8nH 13.7, 0.1% 4:1 1.9mm 1.3mm 0
SIZE 0402 0402 0402 0402 0402 0603 0402 0402 0402 0402 0402 0603 0402 0603 AT224-1 - - 0402
COMMENTS AVX AVX AVX AVX AVX Taiyo Yuden LMK107BJ105MA AVX ACCU-P AVX
Coilcraft 0603CS Toko LL1005-FHL IRC PFC-W0603LF-02-13R7-B Mini-Circuits TC4-1W+ ZO = 70 ZO = 70 AVX/0 Jumper
*Center-to-center spacing between C9 and C3. Center of C9 is 3.0mm from the edge of the package.
Figure 1. Test Circuit Schematic and Component Values
5578f
9
www..com
LT5578
APPLICATIONS INFORMATION
The LT5578 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 LT5578 is intended for operation in the 0.4GHz to 2.7GHz 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 565mV. The optimum DC current in the mixer core is approximately 40mA 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 should be accounted for in the selection of R1 and R2.
R1 IF INPUT LT5578 T1 4:1 C1 L1 TL1 3 IF+ 565mV 2k C9 C2 TL2 4 L2 C3 IF- 565mV 40mA
5578 F02
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 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. 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 10.0 + j1.1 10.2 + j1.5 8.7 + j1.8 8.7 + j2.0 8.7 + j2.5 8.7 + j3.9 8.7 + j4.5 9.6 + j7.6 9.8 + j10.3 REFLECTION COEFFICIENT MAG 0.666 0.661 0.705 0.705 0.705 0.704 0.705 0.683 0.685 ANGLE 177.4 176.5 175.7 175.2 174.0 170.9 169.3 162.0 155.9
40mA
VCC 2k
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 will improve performance. The measured return loss of the IF input is shown in Figure 3 for application frequencies of 70MHz, 140MHz and 240MHz. Component values are listed in Table 2. All of the applications use L1 = L2 = 100nH, R1 = R2 =13.7
5578f
R2
Figure 2. IF Input with External Matching
10
www..com
LT5578
APPLICATIONS INFORMATION
and T1 = TC4-1W+. The 70MHz match was not used for 140MHz characterization because it requires the addition of two inductors.
Table 2. IF Input Component Values
FREQUENCY (MHz) 70 140 240 C1, C2 (pF) 560 220 82 C9 (pF) 82 39 33 C3 (pF) - - 4.7 TL1, TL2 MATCH BW (nH) (at 12dB RL) 3.3 - - 50-215 98-187 175-295
0 0 -5 -5 RETURN LOSS (dB) -10 -15 -20 -25 -30 a b c 50 100 150 200 250 FREQUENCY (MHz) 300 350
5578 F03
LO INPUT
EXTERNAL MATCHING Z1 22 C13 C12 VBIAS
5578 F04
LO
Figure 4. LO Input Circuit
SEE FIGURES 1 AND 8 FOR COMPONENT VALUES
RETURN LOSS (dB)
-10 d -15
-20 a 0 500
b
c 1000 1500 2000 FREQUENCY (MHz) 2500 3000
-25
5578 F05
Figure 3. IF Input Return Loss with 70MHz (a), 140MHz (b) and 240MHz (c) Matching
Figure 5. LO Input Return Loss with 520MHz (a), 760MHz (b), 880MHz (c) and >1.5GHz (d) Matching
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. The primary winding is internally grounded, thus an external DC block may be necessary in some applications. 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 different application frequencies. The impedance match is acceptable from about 1.5GHz to beyond 3GHz, with a minimum return loss across this range of about 9dB. Below 1.5GHz, external components are used to tune the impedance match to the desired frequency.
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) 300 600 900 1200 1500 1800 2100 2400 2700 3000 LO INPUT IMPEDANCE 41.7||j20.3 95.0||j42.7 126||j84.2 127||j239 104||-j686 74.0||-j188 52.5||-j162 42.3||-j459 44.4||j249 52.4||j161 REFLECTION COEFFICIENT MAG 0.747 0.657 0.558 0.456 0.353 0.247 0.158 0.097 0.111 0.159 ANGLE 142.8 105.5 67.6 27.6 -10.8 -48.3 -90.0 -152.0 127.5 90.6
5578f
11
www..com
LT5578
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 LT5578 performs best at frequencies above 700MHz, the part can be used down to 400MHz. The low inductance of the internal transformer limits the performance at lower frequencies. 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 LT5578 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
LT5578 RF 50 RETURN LOSS (dB) C14
the board. As many vias as possible should connect the topside ground to other ground layers to aid in thermal dissipation and reduce inductance.
Table 4. Single-Ended RF Output Impedance (at Pin 15, No External Matching)
FREQUENCY (MHz) 400 800 1200 1600 2000 2400 2800 RF OUTPUT IMPEDANCE 10.1 + j29.3 90.8 + j96.6 69.7 - j66.6 32.8 - j22.5 32.3 - j5.4 28.6 + j0.3 22.5 + j4.4 REFLECTION COEFFICIENT MAG 0.741 0.614 0.507 0.330 0.225 0.273 0.384 ANGLE 117.6 32.6 -44.4 -112.3 -159.3 179.0 167.3
Table 5. RF Output Component Values
FREQUENCY (MHz) C8 (pF) 450 740 900 1950 2600 9.0 3.3 1.8 - - L3 (nH) C14 (pF) 18 18 12 1.8 0 - - - 1.2 0.8 MATCH BW (at 12dB RL) 430-505 680-768 835-970 1765-2305 2150-2990
0
-5
L3 15 C8
-10
-15
8
9
10
11
5578 F06
-20 VCC -25 a 0 b c 500 1000 1500 2000 FREQUENCY (MHz) d e 2500 3000
Figure 6. RF Output Circuit
5578 F07
Figure 7. RF Output Return Loss with 450MHz (a), 740MHz (b), 900MHz (c), 1950MHz (d) and 2600MHz (e) Matching
5578f
12
www..com
LT5578
Figure 9 shows measured conversion gain, noise figure and OIP3 as a function of RF output frequency. At 450MHz, the gain is -2.1dB with a NF of 9.3dB and an OIP3 of 23.8dBm.
12 10 GAIN (dB), NF (dB) 32 30 SSB NF 28 26 24 OIP3 2 0 -2 -4 420 GAIN TA = 25C fIF = 70MHz PIF = -5dBm/TONE 22 20 18 16 500
5578 F09
TYPICAL APPLICATIONS
The following examples illustrate the implementation and performance of the LT5578 in some selected applications. These circuits were evaluated using the board layout shown in Figure 12. 450MHz Application In this case, the LT5578 was evaluated for an application with an IF input at 70MHz, an RF output of 450MHz and a high side LO. The LO port is tuned for high side LO injection at 520MHz. The matching networks for the three ports are shown in Figure 8. At the IF input, the 560pF capacitors are used mainly as DC blocks, but also help tune out the parasitic inductance of the transformer. The 82pF differential capacitor and 3.3nH chip inductors provide an impedance transformation between the IF input pins and the transformer. The relatively low input frequency requires the use of chip inductors instead of the short transmission lines that are shown in Figure 2. The measured IF port return loss is included in Figure 3. The RF port impedance match is realized with a shunt 12pF capacitor and a series 18nH inductor. The return loss with this configuration is better than 12dB from about 430MHz to 505MHz and is plotted in Figure 7. To tune the LO port, a series 6.8pF and shunt 4.7pF capacitor are used as shown. This combination provides a 10dB, or better, return loss from 435MHz to 580MHz as shown in Figure 5. The series capacitor also provides DC decoupling for the internal transformer at the LO input.
8 6 4
OIP3 (dBm)
460 440 480 RF OUTPUT FREQUENCY (MHz)
Figure 9. Gain, Noise Figure and OIP3 vs RF Frequency in the 450MHz Application
2600MHz Application For this application, the impedance match of the RF port is optimized at 2600MHz and has a good return loss over the range of 2200MHz to 2900MHz. The component values are listed in Table 5 and typical output return loss is shown in Figure 7. The IF input is matched at 240MHz as described in Table 2. The LO port requires no external matching for this band as its return loss is good for frequencies above 1.5GHz.
LO 520MHz 13.7 100nH 3.3nH 18nH 82pF 3.3nH 12pF
5578 F08
6.8pF 4.7pF
TC4-1W+ 560pF 4:1 IF 70MHz
RF 450MHz
560pF 13.7
100nH
Figure 8. Schematic for 450MHz RF Application with 70MHz IF and 520MHz LO
5578f
13
www..com
LT5578
TYPICAL APPLICATIONS
The measured room temperature performance is plotted in Figure 10 for both low side and high side LO drive. At 2600MHz, the gain is approximately -2.8dB with a noise figure of 11.2dB and OIP3 of about 22.2dBm. Low side LO yields slightly better overall performance than high side LO. 700 to 950 MHz Output Matching The application shown on page 1 has a wider bandwidth than the 740MHz and 900MHz configurations. Using two additional components at the RF output allows the band12 10 8 GAIN (dB), NF (dB) 6 4 2 0 GAIN -2 -4 2200 2400 2300 2500 2600 RF OUTPUT FREQUENCY (MHz) 18 16 2700
5578 F09
width to be extended to cover the range from 700MHz to 950MHz. Figure 11 compares the broadband return loss to the typical 740MHz and 900MHz return loss performance. The swept gain, noise figure and OIP3 results are plotted on page 1 for an IF of 140MHz and a low side LO. The conversion gain is greater than 0.7dB across the band with OIP3 better than 25.5dBm. The single side-band noise figure is less than 8.8dB across the band.
0
32 SSB NF LS LO HS LO OIP3 RETURN LOSS (dB) 30 28 26 24 22 20 OIP3 (dBm)
-5
-10 c -15
-20 a -25 600 700 b 1100
5578 F11
900 1000 800 FREQUENCY (MHz)
Figure 11. Return Loss Comparison: 740MHz (a), 900MHz (b) and 700MHz to 950MHz (c)
Figure 10. Gain, Noise Figure and OIP3 vs RF Frequency for the 2600MHz Application
Figure 12. LT5578 Evaluation Board (DC1545A)
5578f
14
www..com
LT5578
UH Package 24-Lead Plastic QFN (5mm x 5mm)
(Reference LTC DWG # 05-08-1747 Rev A)
PACKAGE DESCRIPTION
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 PIN 1 NOTCH R = 0.30 TYP OR 0.35 45 CHAMFER
0.65 BSC RECOMMENDED SOLDER PAD LAYOUT APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 5.00 PIN 1 TOP MARK (NOTE 6) 0.10 0.75 0.05 0.00 - 0.05 R = 0.05 TYP BOTTOM VIEW--EXPOSED PAD R = 0.150 TYP
23
24 0.55 1 2 0.10
5.00
0.10
3.25 REF
3.20
0.10
3.20
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
0.05
0.65 BSC
5578f
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.
15
www..com
LT5578
PART NUMBER Infrastructure LT5514 LT5517 LT5518 LT5519 LT5520 LT5521 LT5522 LT5526 LT5527 LT5528
RELATED PARTS
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 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 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 LT5579 1.5GHz to 3.8GHz High Linearity Upconverting 27.3dBm OIP3 at 2.14GHz, NF = 9.9dB, 3.3V Supply, Single-Ended LO and RF Ports Mixer 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 LT5581 6GHz Low Power RMS Detector 40dB Dynamic Range, 1dB Accuracy Over Temperature, 1.5mA Supply Current
5578f
16 Linear Technology Corporation
(408) 432-1900
LT 0709 * PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
FAX: (408) 434-0507 www.linear.com
(c) LINEAR TECHNOLOGY CORPORATION 2009

▲Up To Search▲

Price & Availability of LT5578

	To Download LT5578 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .