LTC5541IUHTRPBF

FEATURES n n n n n n n n n n n n n n LTC5541 1.3GHz to 2.3GHz High Dynamic Range Downconverting Mixer DESCRIPTION The LTC®5541 is part of a family of high dynamic range passive, high gain downconverting mixers covering the 600MHz to 4GHz frequency range. The LTC5541 is optimized for 1.3GHz to 2.3GHz RF applications. The LO frequency must fall within the 1.4GHz to 2.0GHz range for optimum performance. A typical application is a LTE or W-CDMA receiver with a 1.7GHz to 2.2GHz RF input and low-side LO. The LTC5541 is designed for 3.3V operation, however; the IF amplifier can be powered by 5V for the highest P1dB. An integrated SPDT LO switch with fast switching accepts two active LO signals, while providing high isolation. The LTC5541’s high conversion gain and high dynamic range enable the use of lossy IF filters in high-selectivity receiver designs, while minimizing the total solution cost, board space and system-level variation. High Dynamic Range Downconverting Mixer Family PART# LTC5540 LTC5541 LTC5542 LTC5543 RF RANGE 600MHz –1.3GHz 1.3GHz – 2.3GHz 1.6GHz – 2.7GHz 2.3GHz – 4GHz LO RANGE 700MHz – 1.2GHz 1.4GHz – 2.0GHz 1.7GHz – 2.5GHz 2.4GHz – 3.6GHz Conversion Gain: 7.8dB at 1950MHz IIP3: 26.4dBm at 1950MHz Noise Figure: 9.6dB at 1950MHz 16dB NF Under +5dBm Blocking High Input P1dB 3.3V Supply, 630mW Power Consumption Shutdown Pin 50Ω Single-Ended RF and LO Inputs LO Inputs 50Ω Matched when Shutdown High Isolation LO Switch 0dBm LO Drive Level High LO-RF and LO-IF Isolation Small Solution Size 20-Lead (5mm × 5mm) QFN package APPLICATIONS n n n Wireless Infrastructure Receivers (LTE, W-CDMA. TD-SCDMA, UMTS, GSM1800) Point-To-Point Microwave Links High Dynamic Range Downmixer Applications 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. TYPICAL APPLICATION Wideband Receiver 1nF VCCIF 3.3V or 5V 1nF 150nH IF+ IMAGE BPF 2.2pF LNA RF LO IF IF – 22pF LTC5541 LO2 GC (dB) SYNTH 2 ALTERNATE LO FOR FREQUENCY-HOPPING 22pF SHDN (0V/3.3V) SHDN BIAS VCC2 VCC 3.3V 1μF VCC1 22pF VCC3 LO1 LOSEL LO SELECT (0V/3.3V) SYNTH 1 LO 1760MHz 5541 TA01 190MHz SAW IF AMP 190MHz BPF ADC 8.8 8.6 Wideband Conversion Gain, IIP3 and NF vs IF Output Frequency 28 IIP3 26 24 IIP3 (dBm), SSB NF (dB) 22 20 18 16 14 12 10 NF 190 200 170 180 210 IF OUTPUT FREQUENCY (MHz) 8 220 1μF 22pF 150nH RF = 1950 ±30MHz 8.4 LO = 1760MHz P = 0dBm 8.2 LO TEST CIRCUIT IN FIGURE 1 8.0 7.8 7.6 7.4 7.2 7.0 6.8 160 GC RF 1920MHz TO 1980MHz 5541 TA02 5541f 1 LTC5541 ABSOLUTE MAXIMUM RATINGS (Note 1) PIN CONFIGURATION TOP VIEW IFBIAS IFGND 15 LO2 21 GND 14 VCC3 13 GND 12 GND 11 LO1 6 VCC2 7 LOBIAS 8 VCC1 9 10 LOSEL GND GND IF+ IF– Mixer Supply Voltage (VCC1, VCC2)...........................3.8V LO Switch Supply Voltage (VCC3).............................3.8V IF Supply Voltage (IF+, IF –) ......................................5.5V Shutdown Voltage (SHDN) ................–0.3V to VCC +0.3V LO Select Voltage (LOSEL)................–0.3V to VCC +0.3V LO1, LO2 Input Power (1GHz to 3GHz) ...................9dBm LO1, LO2 Input DC Voltage ....................................±0.5V RF Input Power (1GHz to 3GHz) ...........................15dBm RF Input DC Voltage ............................................... ±0.1V Operating Temperature Range .................–40°C to 85°C Storage Temperature Range .................. –65°C to 150°C Junction Temperature (TJ) .................................... 150°C 20 19 18 17 16 NC 1 RF 2 CT 3 GND 4 SHDN 5 UH PACKAGE 20-LEAD (5mm 5mm) PLASTIC QFN TJMAX = 150°C, θJA = 34°C/W, θJC = 3°C/W EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH LTC5541IUH#PBF TAPE AND REEL LTC5541IUH#TRPBF PART MARKING 5541 PACKAGE DESCRIPTION 20-Lead (5mm x 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/ AC ELECTRICAL CHARACTERISTICS PARAMETER LO Input Frequency Range RF Input Frequency Range IF Output Frequency Range RF Input Return Loss LO Input Return Loss IF Output Return Loss LO Input Power LO to RF Leakage LO to IF Leakage LO Switch Isolation RF to LO Isolation RF to IF Isolation Low-Side LO High-Side LO CONDITIONS VCC = 3.3V, VCCIF = 3.3V, SHDN = Low, TA = 25°C, PLO = 0dBm, unless otherwise noted. Test circuit shown in Figure 1. (Notes 2, 3, 4) MIN TYP 1400 to 2000 1600 to 2300 1300 to 1800 5 to 500 >12 >12 >12 –4 0 33 6 MAX UNITS MHz MHz MHz MHz dB dB dB dBm dBm dBm dB dB dB dB 5541f Requires External Matching ZO = 50Ω, 1300MHz to 2300MHz ZO = 50Ω, 1400MHz to 2000MHz Requires External Matching fLO = 1400MHz to 2000MHz fLO = 1400MHz to 2000MHz fLO = 1400MHz to 2000MHz LO1 Selected, 1400MHz < fLO < 2000MHz LO2 Selected, 1400MHz < fLO < 2000MHz fRF = 1300MHz to 2300MHz fRF = 1300MHz to 2300MHz 2 LTC5541 VCC = 3.3V, VCCIF = 3.3V, SHDN = Low, TA = 25°C, PLO = 0dBm, PRF = – 3dBm (Δf = 2MHz for two-tone IIP3 tests),unless otherwise noted. Test circuit shown in Figure 1. (Notes 2, 3, 4) Low-Side LO Downmixer Application: RF = 1700 to 2200MHz, IF = 190MHz, fLO = fRF –fIF PARAMETER Conversion Gain CONDITIONS RF = 1750MHz RF = 1950MHz RF = 2150MHz RF = 1950 ±30MHz, LO = 1760MHz, IF=190 ±30MHz TA = – 40ºC to +85ºC, RF = 1950MHz RF = 1750MHz RF = 1950MHz RF = 2150MHz RF = 1750MHz RF = 1950MHz RF = 2150MHz fRF = 1950MHz, fLO = 1760MHz, fBLOCK = 2050MHz, PBLOCK = 5dBm fRF = 1855MHz at –10dBm, fLO = 1760MHz, fIF = 190MHz fRF = 1823.33MHz at –10dBm, fLO = 1760MHz, fIF = 190MHz RF = 1950MHz, VCCIF = 3.3V RF = 1950MHz, VCCIF = 5V CONDITIONS RF = 1450MHz RF = 1600MHz RF = 1750MHz RF = 1600MHz ±30MHz, LO = 1790MHz, IF = 190 ±30MHz TA = – 40°C to 85°C, RF = 1600MHz RF = 1450MHz RF = 1600MHz RF = 1750MHz RF = 1450MHz RF = 1600MHz RF = 1750MHz fRF = 1600MHz, fLO = 1790MHz, fIF = 190MHz fBLOCK = 1500MHz, PBLOCK = 5dBm fRF = 1695MHz at –10dBm, fLO = 1790MHz fIF = 190MHz fRF = 1726.67MHz at –10dBm, fLO = 1790MHz fIF = 190MHz RF = 1750MHz, VCCIF = 3.3V RF = 1750MHz, VCCIF = 5V MIN 24.0 MIN 6.5 TYP 8.6 7.8 7.6 ±0.1 –0.006 25.5 26.4 25.5 9.2 9.6 10.6 16 –67 –73 11.3 14.6 TYP 8.9 8.4 8.0 ±0.1 –0.006 24.5 24.6 24.3 9.5 9.9 9.9 18 MAX 11.7 MAX UNITS dB dB dB/°C dBm AC ELECTRICAL CHARACTERISTICS Conversion Gain Flatness Conversion Gain vs Temperature Input 3rd Order Intercept SSB Noise Figure dB dB dBc dBc dBm SSB Noise Figure Under Blocking 2RF – 2LO Output Spurious Product (fRF = fLO + fIF/2) 3RF – 3LO Output Spurious Product (fRF = fLO + fIF/3) Input 1dB Compression High-Side LO Downmixer Application: RF = 1300-1800MHz, IF = 190MHz, fLO = fRF +fIF PARAMETER Conversion Gain UNITS dB Conversion Gain Flatness Conversion Gain vs Temperature Input 3rd Order Intercept dB dB/°C dBm SSB Noise Figure dB SSB Noise Figure Under Blocking 2LO – 2RF Output Spurious Product (fRF = fLO – fIF/2) 3LO – 3RF Output Spurious Product (fRF = fLO – fIF/3) Input 1dB Compression dB dBc –69 dBc –74 11.1 14.4 dBm 5541f 3 LTC5541 noted. Test circuit shown in Figure 1. (Note 2) PARAMETER Power Supply Requirements (VCC, VCCIF) VCC Supply Voltage (Pins 6, 8 and 14) VCCIF Supply Voltage (Pins 18 and 19) VCC Supply Current (Pins 6 + 8 + 14) VCCIF Supply Current (Pins 18 + 19) Total Supply Current (VCC + VCCIF) Total Supply Current – Shutdown SHDN Input High Voltage (Off) SHDN Input Low Voltage (On) SHDN Input Current Turn On Time Turn Off Time LO Select Logic Input (LOSEL) Low = LO1 Selected, High = LO2 Selected LOSEL Input High Voltage LOSEL Input Low Voltage LOSEL Input Current LO Switching Time 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: The LTC5541 is guaranteed functional over the operating temperature range from –40°C to 85°C. –0.3V to VCC + 0.3V –20 50 3 0.3 30 V V μA ns –0.3V to VCC + 0.3V –20 1 1.5 SHDN = High 3 0.3 30 Shutdown Logic Input (SHDN) Low = On, High = Off V V μA μs μs 3.1 3.1 3.3 3.3 92 100 192 3.5 5.3 108 120 228 500 V V mA μA DC ELECTRICAL CHARACTERISTICS CONDITIONS VCC = 3.3V, VCCIF = 3.3V, SHDN = Low, TA = 25°C, unless otherwise MIN TYP MAX UNITS Note 3: SSB Noise Figure measurements performed with a small-signal noise source, bandpass filter and 6dB matching pad on RF input, bandpass filter and 6dB matching pad on the LO input, and no other RF signals applied. Note 4: LO switch isolation is measured at the IF output port at the IF frequency with fLO1 and fLO2 offset by 2MHz. TYPICAL DC PERFORMANCE CHARACTERISTICS VCC Supply Current vs Supply Voltage (Mixer and LO Switch) 100 98 96 SUPPLY CURRENT (mA) SUPPLY CURRENT(mA) 94 92 90 88 86 84 82 80 3.0 3.1 3.4 3.2 3.3 3.5 VCC SUPPLY VOLTAGE (V) 3.6 5541 G01 SHDN = Low, Test circuit shown in Figure 1. VCCIF Supply Current vs Supply Voltage (IF Amplifier) 125 220 210 SUPPLY CURRENT(mA) 200 190 180 170 –40°C 75 3.0 3.3 3.6 3.9 4.2 4.5 4.8 5.1 VCCIF SUPPLY VOLTAGE (V) 5.4 Total Supply Current vs Temperature (VCC + VCCIF) VCC = 3.3V, VCCIF = 5V (DUAL SUPPLY) 115 85°C 25°C –40°C 85°C 105 25°C 95 VCC = VCCIF = 3.3V (SINGLE SUPPLY) 85 160 –45 –25 55 –5 15 35 TEMPERATURE (°C) 75 95 5541 G02 5541 G03 5541f 4 LTC5541 Low-Side LO VCC = 3.3V, VCCIF = 3.3V, SHDN = Low, TA = 25°C, PLO = 0dBm, PRF = – 3dBm (–3dBm/tone for two-tone IIP3 tests, Δf = 2MHz), IF = 190MHz, unless otherwise noted. Test circuit shown in Figure 1. Conversion Gain, IIP3 and NF vs RF Frequency 28 26 GC (dB), IIP3 (dBm), SSB NF (dB) 24 LO LEAKAGE (dBm) 22 20 18 16 14 12 10 8 6 1.65 1.75 30 GC 1.85 1.95 2.05 RF FREQUENCY (GHz) 2.15 2.25 –60 1.2 1.4 1.6 1.8 2.0 LO FREQUENCY (GHz) 2.2 5541 G05 TYPICAL AC PERFORMANCE CHARACTERISTICS LO Leakage vs LO Frequency –20 RF Isolation vs RF Frequency 65 60 IIP3 –30 ISOLATION (dB) LO-IF –40 LO-RF –50 55 50 45 40 35 RF-LO RF-IF NF 25 1.3 1.5 1.7 1.9 2.1 RF FREQUENCY (GHz) 2.3 5541 G06 5541 G04 1750MHz Conversion Gain, IIP3 and NF vs LO Power 27 25 23 GC (dB), IIP3 (dBm) 21 19 17 15 13 11 9 7 –6 –4 4 –2 0 2 LO INPUT POWER (dBm) 6 5541 G07 1950MHz Conversion Gain, IIP3 and NF vs LO Power 20 18 27 25 23 GC (dB), IIP3 (dBm) 21 19 17 15 13 11 9 7 –6 –4 4 –2 0 2 LO INPUT POWER (dBm) 6 5541 G08 2150MHz Conversion Gain, IIP3 and NF vs LO Power 20 26 24 IIP3 22 GC (dB), IIP3 (dBm) 20 18 16 14 12 10 8 6 –6 –4 4 –2 0 2 LO INPUT POWER (dBm) 6 5541 G09 IIP3 21 19 85°C 17 25°C –40°C 15 13 11 NF 9 7 5 GC 3 1 IIP3 18 85°C 16 25°C –40°C 14 12 10 NF 8 6 4 85°C 25°C 14 –40°C 12 NF 10 8 6 GC 4 2 0 16 SSB NF (dB) SSB NF (dB) SSB NF (dB) GC 2 0 Conversion Gain, IIP3 and NF vs Supply Voltage (Single Supply) 27 25 23 GC (dB), IIP3 (dBm) 21 19 17 15 13 11 9 7 3.0 GC NF IIP3 20 18 85°C 16 25°C –40°C 14 12 10 8 6 29 27 25 GC (dB), IIP3 (dBm) 23 21 19 17 15 13 11 9 Conversion Gain, IIP3 and NF vs IF Supply Voltage (Dual Supply) 22 IIP3 20 85°C 25°C 16 –40°C 14 NF 12 10 8 RF = 1950MHz 6 VCC = 3.3V 4 2 3.6 3.9 4.2 4.5 4.8 5.1 VCCIF SUPPLY VOLTAGE (V) 0 5.4 18 GC (dB), IIP3 (dBm), P1dB (dBm) 28 26 24 22 20 18 16 14 12 10 8 1950MHz Conversion Gain, IIP3 and RF Input P1dB vs Temperature IIP3 VCCIF = 5.0V VCCIF = 3.3V SSB NF (dB) SSB NF (dB) P1dB RF = 1950MHz VCC = VCCIF 4 2 3.5 3.1 3.2 3.3 3.4 VCC, VCCIF SUPPLY VOLTAGE (V) 0 3.6 5541 G10 GC 7 3.0 3.3 GC 6 –45 –25 –5 15 35 55 TEMPERATURE (°C) 75 95 5541 G11 5541 G12 5541f 5 LTC5541 Low-Side LO (continued) VCC = 3.3V, VCCIF = 3.3V, SHDN = Low, TA = 25°C, PLO = 0dBm, PRF = – 3dBm (–3dBm/tone for two-tone IIP3 tests, Δf = 2MHz), IF = 190MHz, unless otherwise noted. Test circuit shown in Figure 1. 2-Tone IF Output Power, IM3 and IM5 vs RF Input Power 20 10 OUTPUT POWER/TONE (dBm) 0 –10 –20 –30 –40 –50 –60 –70 –80 –12 IM3 IM5 –9 –6 –3 0 3 RF INPUT POWER (dBm/TONE) 6 5541 G13 TYPICAL AC PERFORMANCE CHARACTERISTICS Single-Tone IF Output Power, 2 × 2 and 3 × 3 Spurs vs RF Input Power 20 IFOUT OUTPUT POWER (dBm) RF1 = 1949MHz RF2 = 1951MHz LO = 1760MHz IFOUT 10 (RF = 1950MHz) 0 –10 –20 –30 –40 –50 –60 –70 –80 –12 –9 2RF-2LO (RF = 1855MHz) 3RF-3LO (RF = 1823.33MHz) LO = 1760MHz 2 × 2 and 3 × 3 Spur Suppression vs LO Power –50 –55 –60 –65 –70 –75 –80 3RF-3LO (RF = 1823.33MHz) –6 –4 4 –2 0 2 LO INPUT POWER (dBm) 6 5541 G15 RELATIVE SPUR LEVEL (dBc) RF = 1950MHz PRF = –10dBm LO = 1760MHz 2RF-2LO (RF = 1855MHz) 3 6 9 –6 –3 0 RF INPUT POWER (dBm) 12 15 5541 G14 SSB Noise Figure vs RF Blocker Level 17 16 15 ISOLATION (dB) SSB NF (dB) 14 13 12 11 10 9 –25 PLO = 3dBm 0 –20 –15 –10 –5 RF BLOCKER POWER (dBm) 5 5541 G16 LO Switch Isolation vs LO Frequency–LO1 Selected 60 PLO2 = –3dBm 55 ISOLATION (dB) PLO2 = 0dBm 50 PLO2 = 3dBm 45 LOSEL = LOW PLO1 = 0dBm 1.4 1.6 1.8 2.0 LO FREQUENCY (GHz) 2.2 5541 G17 LO Switch Isolation vs LO Frequency–LO2 Selected 60 PLO1 = –3dBm 55 PLO1 = 0dBm 50 RF = 1950MHz BLOCKER = 2050MHz PLO = –3dBm PLO = 0dBm 45 PLO1 = 3dBm 40 1.2 40 1.2 LOSEL = HIGH PLO2 = 0dBm 1.4 1.6 1.8 2.0 LO FREQUENCY (GHz) 2.2 5541 G18 Conversion Gain Distribution 40 35 30 DISTRIBUTION (%) DISTRIBUTION (%) 25 20 15 10 5 0 6.9 7.1 7.3 7.5 7.7 7.9 8.1 8.3 8.5 CONVERSION GAIN (dB) 5541 G18a IIP3 Distribution 85°C 25°C –40°C 20 18 16 14 12 10 8 6 4 2 0 25.0 25.4 25.8 26.2 26.6 IIP3 (dBm) 27.0 27.4 5541 G18b SSB Noise Figure Distribution 85°C 25°C –40°C DISTRIBUTION (%) 35 30 25 20 15 10 5 0 8.2 8.6 9.0 9.4 9.8 10.2 10.6 11.0 SSB NOISE FIGURE (dB) 5541 G18c RF = 1950MHz RF = 1950MHz RF = 1950MHz 85°C 25°C –40°C 5541f 6 LTC5541 High-Side LO VCC = 3.3V, VCCIF = 3.3V, SHDN = Low, TA = 25°C, PLO = 0dBm, PRF = – 3dBm (–3dBm/tone for two-tone IIP3 tests, Δf = 2MHz), IF = 190MHz, unless otherwise noted. Test circuit shown in Figure 1. Conversion Gain, IIP3 and NF vs RF Frequency 25 IIP3 GC (dB), IIP3 (dBm), SSB NF (dB) 23 21 19 17 15 13 11 9 7 1250 1350 GC 1450 1550 1650 1750 RF FREQUENCY (MHz) 1850 SSB NF GC (dB), IIP3 (dBm), P1dB (dBm) 23 21 19 17 15 13 11 9 7 –45 P1dB GC –25 55 –5 15 35 TEMPERATURE (°C) 75 95 VCCIF = 5.0V VCCIF = 3.3V 25 IIP3 GC (dB), IIP3 (dBm), P1dB (dBm) TYPICAL AC PERFORMANCE CHARACTERISTICS 1450MHz Conversion Gain, IIP3 and RF Input P1dB vs Temperature 25 23 21 19 17 15 13 11 9 1750MHz Conversion Gain, IIP3 and RF Input P1dB vs Temperature IIP3 VCCIF = 5.0V VCCIF = 3.3V P1dB GC 7 –45 –25 –5 15 35 55 TEMPERATURE (°C) 75 95 5541 G19 5541 G20 5541 G21 1450MHz Conversion Gain, IIP3 and NF vs LO Power 26 IIP3 24 22 GC (dB), IIP3 (dBm) 20 18 16 14 12 10 8 –6 –4 4 –2 0 2 LO INPUT POWER (dBm) 6 5541 G22 1600MHz Conversion Gain, IIP3 and NF vs LO Power 18 16 14 GC (dB), IIP3 (dBm) 12 SSB NF (dB) 10 27 25 23 21 19 17 15 13 11 9 7 –6 –4 4 –2 0 2 LO INPUT POWER (dBm) 6 5541 G22b 1750MHz Conversion Gain, IIP3 and NF vs LO Power 20 25 23 21 GC (dB), IIP3 (dBm) 19 17 15 13 11 9 7 –6 –4 4 –2 0 2 LO INPUT POWER (dBm) 6 5541 G23 IIP3 18 16 14 12 SSB NF (dB) 10 NF 8 IIP3 18 16 14 SSB NF (dB) 12 10 NF 8 85°C 6 25°C –40°C 4 NF 8 85°C 6 25°C –40°C 4 GC 2 0 85°C 6 25°C –40°C 4 GC 2 0 GC 2 0 2-Tone IF Output Power, IM3 and IM5 vs RF Input Power 20 10 OUTPUT POWER/TONE (dBm) 0 –10 RF1 = 1599MHz –20 RF2 = 1601MHz –30 LO = 1790MHz –40 –50 –60 –70 –80 –12 3 –9 –6 –3 0 RF INPUT POWER (dBm/TONE) 6 5541 G24 Single-Tone IF Output Power, 2 × 2 and 3 × 3 Spurs vs RF Input Power 20 IFOUT 10 (RF = 1600MHz) OUTPUT POWER (dBm) LO = 1790MHz RELATIVE SPUR LEVEL (dBc) 0 –10 –20 –30 –40 –50 –60 –70 –80 –12 –9 –80 3 6 9 –6 –3 0 RF INPUT POWER (dBm) 12 15 3LO-3RF (RF = 1726.67MHz) 2LO-2RF (RF = 1695MHz) –50 –55 –60 –65 –70 –75 2 × 2 and 3 × 3 Spur Suppression vs LO Power RF = 1600MHz PRF = –10dBm LO = 1790MHz IFOUT 2LO-2RF (RF = 1695MHz) IM3 IM5 3LO-3RF (RF = 1726.67MHz) –6 –4 4 –2 0 2 LO INPUT POWER (dBm) 6 5541 G26 5541 G25 5541f 7 LTC5541 PIN FUNCTIONS NC (Pin 1): This pin is not connected internally. It can be left floating, connected to ground or to VCC . RF (Pin 2): Single-Ended Input for the RF Signal. This pin is internally connected to the primary side of the RF input transformer, which has low DC resistance to ground. A series DC-blocking capacitor should be used to avoid damage to the integrated transformer. The RF input is impedance matched, as long as the selected LO input is driven with a 0dBm ±6dB source between 1.4GHz and 2GHz. CT (Pin 3): RF Transformer Secondary Center-Tap. This pin may require a bypass capacitor to ground. See the Applications Information section. This pin has an internally generated bias voltage of 1.2V. It must be DC-isolated from ground and VCC. GND (Pins 4, 10, 12, 13, 17, Exposed Pad Pin 21): Ground. These pins must be soldered to the RF ground plane on the circuit board. The exposed pad metal of the package provides both electrical contact to ground and good thermal contact to the printed circuit board. SHDN (Pin 5): Shutdown Pin. When the input voltage is less than 0.3V, the internal circuits supplied through pins 6, 8, 14, 18 and 19 are enabled. When the input voltage is greater than 3V, all circuits are disabled. Typical input current is less than 10μA. This pin must not be allowed to float. VCC2 (Pin 6) and VCC1 (Pin 8): Power Supply Pins for the LO Buffer and Bias Circuits. These pins are internally connected and must be externally connected to a regulated 3.3V supply, with bypass capacitors located close to the pin. Typical current consumption is 92mA. LOBIAS (Pin 7): This Pin Allows Adjustment of the LO Buffer Current. Typical DC voltage is 2.2V. LOSEL (Pin 9): LO1/LO2 Select Pin. When the input voltage is less than 0.3V, the LO1 port is selected. When the input voltage is greater than 3V, the LO2 port is selected. Typical input current is 11μA for LOSEL = 3.3V. This pin must not be allowed to float. LO1 (Pin 11) and LO2 (Pin 15): Single-Ended Inputs for the Local Oscillators. These pins are internally biased at 0V and require external DC blocking capacitors. Both inputs are internally matched to 50Ω, even when the chip is disabled (SHDN = high). VCC3 (Pin 14): Power Supply Pin for the LO Switch. This pin must be connected to a regulated 3.3V supply and bypassed to ground with a capacitor near the pin. Typical DC current consumption is less than 100μA. IFGND (Pin 16): DC Ground Return for the IF Amplifier. This pin must be connected to ground to complete the IF amplifier’s DC current path. Typical DC current is 100mA. IF – (Pin 18) and IF + (Pin 19): Open-Collector Differential Outputs for the IF Amplifier. These pins must be connected to a DC supply through impedance matching inductors, or a transformer center-tap. Typical DC current consumption is 50mA into each pin. IFBIAS (Pin 20): This Pin Allows Adjustment of the IF Amplifier Current. Typical DC voltage is 2.1V. 5541f 8 LTC5541 BLOCK DIAGRAM 20 19 18 16 21 IF+ IFBIAS IF – IFGND EXPOSED PAD IF AMP 2 RF LO AMP CT SHDN PASSIVE MIXER BIAS LOSEL 9 LO1 11 LO2 15 VCC3 14 3 5 VCC2 6 VCC1 8 7 LOBIAS GND PINS ARE NOT SHOWN 5541 BD TEST CIRCUIT 4:1 T1 C10 L1 VCCIF 3.1V TO 5.3V 100mA L2 IFOUT 190MHz 50Ω L1, L2 vs IF Frequencies IF (MHz) 140 190 240 L1, L2 (nH) 270 150 100 56 33 C9 C8 20 IFBIAS 1 NC C1 RFIN 50Ω 2 RF 19 IF+ 18 IF – 17 GND 16 IFGND LO2 15 C4 LO2IN 50Ω 300 380 REF DES VCC3 14 C7 VALUE 2.2pF 22pF 1μF 1000pF 150nH TC4-1W-7ALN+ (WBC4-6TLB) SIZE 0402 0402 0603 0402 COMMENTS AVX AVX AVX AVX Mini-Circuits (Coilcraft) C1 C3, C4, C6, C7, C8 C5, C9 C10 C3 3 CT LTC5541 GND 13 4 GND GND 12 L1, L2 LO1IN 50Ω 0603 Coilcraft 0603CS SHDN (0V/3.3V) 5 SHDN VCC2 6 LOBIAS 7 VCC1 8 LOSEL 9 LO1 11 GND 10 T1 (Alternate) VCC 3.1V TO 3.5V 92mA C5 C6 5541 TC LOSEL (0V/3.3V) RF GND DC1431A BOARD BIAS STACK-UP GND (NELCO N4000-13) 0.015” 0.062” 0.015” Figure 1. Standard Downmixer Test Circuit Schematic (190MHz IF) 5541f 9 LTC5541 APPLICATIONS INFORMATION Introduction The LTC5541 consists of a high linearity passive doublebalanced mixer core, IF buffer amplifier, high speed singlepole double-throw (SPDT) LO switch, LO buffer amplifier and bias/shutdown circuits. See Block Diagram section for a description of each pin function. The RF and LO inputs are single-ended. The IF output is differential. Low-side or high-side LO injection can be used. The evaluation circuit, shown in Figure 1, utilizes bandpass IF output matching and an IF transformer to realize a 50Ω single-ended IF output. The evaluation board layout is shown in Figure 2. applications. When used, C2 should be located within 2mm of pin 3 for proper high-frequency decoupling. The nominal DC voltage on the CT pin is 1.2V. For the RF input to be matched, the selected LO input must be driven. A broadband input match is realized with C1 = 2.2pF. The measured input return loss is shown in Figure 4 for LO frequencies of 1.4GHz, 1.75GHz and 2GHz. These LO frequencies correspond to the lower, middle and upper values of the LO range. As shown in Figure 4, the RF input impedance is somewhat dependent on LO frequency, although a single value of C1 is adequate to cover the 1.3GHz-2.3GHz RF band. TO MIXER RFIN C1 2 RF 3 C2 CT LTC5541 5541 F02 5541 F03 Figure 2. Evaluation Board Layout Figure 3. RF Input Schematic 0 –5 LO = 2GHz RETURN LOSS (dB) –10 –15 –20 LO = 1.4GHz –25 LO = 1.75GHz –30 1.0 1.5 2.0 2.5 FREQUENCY (GHz) 3.0 5541 F04 RF Input The mixer’s RF input, shown in Figure 3, is connected to the primary winding of an integrated transformer. A 50Ω match is realized when a series capacitor, C1, is connected to the RF input. C1 is also needed for DC blocking if the RF source has DC voltage present, since the primary side of the RF transformer is DC-grounded internally. The DC resistance of the primary is approximately 3.6Ω. The secondary winding of the RF transformer is internally connected to the passive mixer. The center-tap of the transformer secondary is connected to pin 3 (CT) to allow the connection of bypass capacitor, C2. The value of C2 is LO frequency-dependent and is not required for most Figure 4. RF Input Return Loss 5541f 10 LTC5541 APPLICATIONS INFORMATION The RF input impedance and input reflection coefficient, versus RF frequency, is listed in Table 1. The reference plane for this data is pin 2 of the IC, with no external matching, and the LO is driven at 1.75GHz. Table 1. RF Input Impedance and S11 (at Pin 2, No External Matching, LO Input Driven at 1.75GHz) FREQUENCY (GHz) 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 INPUT IMPEDANCE 24.1 + j42.1 33.1 + j47.2 43.6 + j49.2 58.0 + j47.1 50.2 + j20.6 43.0 + j32.4 43.7 + j37.8 44.1 + j44.4 49.0 + j51.7 56.8 + j57.6 68.9 + j61.0 S11 MAG 0.58 0.53 0.47 0.41 0.20 0.34 0.39 0.43 0.47 0.48 0.48 ANGLE 92.1 79.8 69.7 56.9 77.8 82.9 79.0 72.4 63.6 55.0 45.7 The LO switch is designed for high isolation and fast (36dBm OIP3 at 300MHz, Differential I/O Fixed Gain of 8dB, 14dB, 20dB and 26dB; >40dBm OIP3 at 140MHz, Differential I/O 40.25dBm OIP3 to 300MHz, Programmable Fast Recovery Output Clamping 35dBm OIP3 at 240MHz, Continuous Gain Range –14dB to 17dB 48dBm OIP3 at 200MHz, 2dB to 18dB Gain Range, 0.125dB Gain Steps 2.9dB Conversion Gain, 24.7dBm IIP3 and 11.7dB NF at 1950MHz, 3.3V/82mA Supply Integrated Baluns, 28dBm IIP3, 13dBm P1dB, 0.03dB I/Q Amplitude Match, 0.4° Phase Match 27dBm OIP3 at 900MHz, 24.2dBm at 1.95GHz, Integrated RF Transformer 27.3dBm OIP3 at 2.14GHz, NF = 9.9dB, 3.3V Supply, Single-Ended LO and RF Ports 27.7dBm OIP3 at 140MHz, 22.9dBm at 900MHz, –161.2dBm/Hz Noise Floor ±1dB Output Variation over Temperature, 38ns Response Time, Log Linear Response Low Frequency to 1GHz, 83dB Log Linear Dynamic Range ±0.5dB Accuracy Over Temperature and >50dB Dynamic Range, Fast 500ns Rise Time 40dB Dynamic Range, ±1dB Accuracy Over Temperature, 1.5mA Supply Current 78dBFS Noise Floor, >83dB SFDR at 250MHz 72.8dB SNR, 88dB SFDR, 149mW Power Consumption 65.4dB SNR, 78dB SFDR, 740mW Power Consumption 5541f LT 1209 • PRINTED IN USA 700MHz to 2.7GHz Direct Conversion I/Q Demodulator LT5578 400MHz to 2.7GHz High Linearty Upconverting Mixer LT5579 1.5GHz to 3.8GHz High Linearity Upconverting Mixer LTC5598 5MHz to 1.6GHz I/Q Modulator RF Power Detectors LT5534 50MHz to 3GHz Log RF Power Detector with 60dB Dynamic Range LT5537 Wide Dynamic Range Log RF/IF Detector LT5570 2.7GHz Mean-Squared Detector LT5581 ADCs LTC2208 LTC2262-14 LTC2242-12 6GHz Low Power RMS Detector 16-Bit, 130Msps ADC 14-Bit, 150Msps ADC Ultralow Power at 1.8V Supply 12-Bit, 250Msps ADC 16 Linear Technology Corporation (408) 432-1900 ● FAX: (408) 434-0507 ● 1630 McCarthy Blvd., Milpitas, CA 95035-7417 www.linear.com © LINEAR TECHNOLOGY CORPORATION 2009