LT5579IUH-PBF

LT5579 1.5GHz to 3.8GHz High Linearity Upconverting Mixer FEATURES n n n n n n n n n DESCRIPTION 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. 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 APPLICATIONS n n n n 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 = 25°C VCC = 3.3V fIF = 240MHz fLO = fRF + fIF OIP3 GND 11Ω 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 1μF 100pF 5579 TA01a 11Ω 1nF VCC 3.3V 5579f 1 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 .................................................................... 150°C Operating Temperature Range.................. –40°C to 85°C Storage Temperature Range................... –65°C to 150°C UH PACKAGE 24-LEAD (5mm 5mm) PLASTIC QFN TJMAX = 150°C, θJA = 34°C/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 × 5mm) Plastic QFN TEMPERATURE RANGE –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 Power Supply Requirements (VCC) Supply Voltage Supply Current Input Common Mode Voltage (VCM) CONDITIONS VCC = 3.3V, TA = 25°C (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 5579f 2 LT5579 VCC = 3.3V, TA = 25°C, PRF = –5dBm (–5dBm/tone for 2-tone tests, Δf = 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 AC ELECTRICAL CHARACTERISTICS VCC = 3.3V, TA = 25°C, PRF = –5dBm (–5dBm/tone for 2-tone tests, Δf = 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 = –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 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 –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. 5579f 3 LT5579 TYPICAL DC PERFORMANCE CHARACTERISTICS Supply Current vs Supply Voltage 255 245 SUPPLY CURRENT (mA) 235 225 215 205 195 85°C 25°C –40°C 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 = 25°C, fIF = 456MHz, PIF = –5dBm (–5dBm/tone for 2-tone tests, Δf = 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 = 90°C TA = 25°C TA = –45°C 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 = 90°C TA = 25°C TA = –45°C 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 = 90°C TA = 25°C TA = –45°C 10 10 11 12 13 NOISE FIGURE (dB) 14 5579 G04 5579f 4 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 = 25°C, fIF = 456MHz, PIF = –5dBm (–5dBm/tone for 2-tone tests, Δf = 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) 85°C 25°C –40°C OIP3 (dBm) 4 GAIN 0 85°C 25°C –40°C –20 16 –30 12 –40 4 3200 3300 3400 3500 3600 3700 3800 3900 RF FREQUENCY (MHz) 5579 G06 85°C 25°C –40°C –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 85°C 25°C –40°C 14 4 GAIN 85°C 25°C –40°C 18 14 10 85°C 25°C –40°C –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) 85°C 25°C –40°C 6 14 12 10 8 6 4 3.0 3.1 3.2 3.4 3.3 SUPPLY VOLTAGE (V) 85°C 25°C –40°C 3.5 3.6 5579 G13 –40 –40 –60 –60 –80 85°C 25°C –40°C 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 5579f 5 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 85°C 25°C –40°C 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 85°C 25°C –40°C 2500 2600 2700 RF FREQUENCY (MHz) 2800 LO LEAKAGE (dBm) –20 2300MHz to 2700MHz Application: VCC = 3.3V, TA = 25°C, fIF = 456MHz, PIF = –5dBm (–5dBm/tone for 2-tone tests, Δf = 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 85°C 25°C –40°C 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 85°C 25°C –40°C 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 85°C 25°C –40°C GAIN 12 24 OIP3 (dBm) OIP3 (dBm) GAIN (dB) GAIN (dB) 8 20 8 20 4 16 4 16 0 12 85°C 25°C –40°C –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 85°C 25°C –40°C 6 –80 85°C 25°C –40°C 6 4 2 3.0 3.1 3.2 3.4 3.3 SUPPLY VOLTAGE (V) 85°C 25°C –40°C 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 5579f 6 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 85°C 25°C –40°C 2150 2250 2050 RF FREQUENCY (MHz) 14 4 2 1950 2150 2050 2250 RF FREQUENCY (MHz) 85°C 25°C –40°C 2350 5579 G24 2140MHz Application: VCC = 3.3V, TA = 25°C, fIF = 240MHz, PIF = –5dBm (–5dBm/tone for 2-tone tests, Δf = 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 85°C 25°C –40°C 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 85°C 25°C –40°C –13 –5 –1 –9 LO INPUT POWER (dBm) 14 85°C 25°C –40°C –6 –10 –2 LO INPUT POWER (dBm) 2 5579 G27 0 85°C 25°C –40°C 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 85°C 25°C –40°C 0 –8 –6 –4 –2 2 4 RF OUTPUT POWER (dBm/TONE) 6 –80 85°C 25°C –40°C 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) 85°C 25°C –40°C 3.5 3.6 5579 G31 –100 –10 –100 –10 5579 G29 5579 G30 5579f 7 LT5579 TYPICAL PERFORMANCE CHARACTERISTICS 1750MHz Application: VCC = 3.3V, TA = 25°C, fIF = 240MHz, PIF = –5dBm (–5dBm/tone for 2-tone tests, Δf = 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 85°C 25°C –40°C 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 85°C 25°C –40°C –10 LO LEAKAGE (dBm) 85°C 25°C –40°C 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 85°C 25°C –40°C 24 20 0 –4 –17 85°C 25°C –40°C –13 –5 –1 –9 LO INPUT POWER (dBm) 3 5579 G35 14 4 10 2 –17 –13 –1 –5 LO INPUT POWER (dBm) –9 85°C 25°C –40°C 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 85°C 25°C –40°C 0 –8 –6 –4 –2 2 4 RF OUTPUT POWER (dBm/TONE) 6 –80 85°C 25°C –40°C 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) 85°C 25°C –40°C 3.5 3.6 5579 G40 –100 –10 –100 –10 5579 G38 5579 G39 5579f 8 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. 5579f 9 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 5579f 10 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 1μF 1.2pF 33pF 40nH 6.8nH 11Ω, 0.1% 4:1 — 2.3mm fRF = 2140MHz fIF = 240MHz 82pF — 100pF 10pF 1nF 1μF 0.45pF 33pF 40nH 1.8nH 11Ω, 0.1% 4:1 — 2.3mm fRF = 2600MHz fIF = 456MHz 33pF 2.7pF 100pF 10pF 1nF 1μF — 33pF 40nH 1nH 11Ω, 0.1% 4:1 1.3mm 2.3mm fRF = 3600MHz fIF = 456MHz 33pF 1.8pF 100pF 10pF 1nF 1μF 0.7pF 33pF 40nH 0Ω 11Ω, 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/0Ω Jumper IRC PFC-W0603R-03-11R1-B M/A-COM MABAES0061 ZO = 70Ω Microstrip ZO = 70Ω 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 5579f 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. 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 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 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 5579f 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) 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) (Ω) (at 12dB RL) 100 40 40 9.1 11 11 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 5579f 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 © LINEAR TECHNOLOGY CORPORATION 2008