LT5511 High Signal Level Upconverting Mixer U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO The LT®5511 mixer is designed to meet the high linearity requirements of cable TV infrastructure downstream transmitters and wireless infrastructure transmit systems. The IC includes a differential LO buffer amplifier driving a double-balanced mixer. The LO, RF and IF ports can be easily matched to a broad range of frequencies for different applications. The high performance capability of the LO buffer allows the use of a single-ended source, thus eliminating the need for an LO balun. Wide RF Output Frequency Range to 3000MHz Broadband RF and IF Operation +17dBm Typical Input IP3 (at 950MHz) +6dBm IF Input for 1dB RF Output Compression Integrated LO Buffer: –10dBm Drive Level Single-Ended or Differential LO Input Double-Balanced Mixer Enable Function Single 4.0V – 5.25V Supply Voltage Range 16-Pin TSSOP Exposed Pad Package The LT5511 mixer delivers +17dBm typical input 3rd order intercept point at 950MHz, and +15.5dBm IIP3 at 1900MHz, with IF input signal levels of – 5dBm. The input 1dB compression point is typically +6dBm. U APPLICATIO S ■ ■ ■ CATV Downlink Infrastructure Wireless Infrastructure High Linearity Mixer Applications , LTC and LT are registered trademarks of Linear Technology Corporation. U TYPICAL APPLICATIO VCC 5V ENABLE RF Output Power and 3rd Order Intermodulation vs Input Power (Two Input Tones) LT5511 EN VCCBIAS VCCLO BIAS MOD IF+ 0 TO DOWNMIXER RF – IF– 10 950MHz RF + –10 POUT, IM3 (dBm/TONE) 44MHz GND –20 –30 –40 –50 LO– –70 –90 5511 F01a LO INPUT 994MHz –10dBm IM3 –60 –80 LO+ POUT –100 –20 PLO = –10dBm fRF1 = 950MHz fRF2 = 949MHz TA = 25°C –15 –5 0 –10 IF INPUT POWER (dBm/TONE) 5 5511 F01b Figure 1. High Signal Level Upmixer for CATV Downlink Infrastructure. 5511i 1 LT5511 U W W W ABSOLUTE AXI U RATI GS U W U PACKAGE/ORDER I FOR ATIO (Note 1) Supply Voltage ....................................................... 5.5V Enable Voltage ................................ –0.3V to VCC + 0.3V LO Input Power (Differential) .............................. 10dBm IF Input Power (Differential) ............................... 10dBm IF+, IF– DC Currents .............................................. 25mA Operating Temperature Range .................–40°C to 85°C Storage Temperature Range ..................–65°C to 150°C Lead Temperature (Soldering, 10sec)................... 300°C ORDER PART NUMBER TOP VIEW LO– 1 16 LO NC 2 15 VCCLO GND 3 14 GND + IF+ 4 13 IF– 5 12 RF – GND 6 11 GND VCCBIAS 7 10 EN GND 8 9 LT5511EFE RF+ FE PART MARKING NC 5511EFE FE PACKAGE 16-LEAD PLASTIC TSSOP TJMAX = 150°C, θJA = 38°C/W EXPOSED PAD IS GROUND (MUST BE SOLDERED TO PRINTED CIRCUIT BOARD) Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS PARAMETER CONDITIONS MIN TYP MAX UNITS VCC = 5VDC, EN = High, TA = 25°C IF Input Frequency Range (Note 6) 1 to 300 MHz LO Input Frequency Range (Note 6) 30 to 2700 MHz RF Output Frequency Range (Note 6) 10 to 3000 MHz 950MHz Application: (Test Circuit Shown in Figure 2) VCC = 5VDC, EN = High, TA = 25°C, IF Input = 50MHz at –5dBm, LO Input = 1GHz at –10dBm, RF Output Measured at 950MHz, unless otherwise noted. (Notes 2, 3) IF Input Return Loss With External Matching, ZO = 50Ω LO Input Power 14 –15 to –5 dB dBm LO Input Return Loss With External Matching, ZO = 50Ω 14 dB RF Output Return Loss With External Matching, ZO = 50Ω 17 dB Conversion Gain 0 LO to RF Leakage –46 dBm dB Input 1dB Compression 5.9 dBm Input 3rd Order Intercept Two-Tone, –5dBm/Tone, ∆f = 1MHz 17 dBm Input 2nd Order Intercept Single-Tone, –5dBm 52 dBm 15 dB SSB Noise Figure 5511f 2 LT5511 ELECTRICAL CHARACTERISTICS PARAMETER CONDITIONS MIN TYP MAX UNITS 1.9GHz Application: (Test Circuit Shown in Figure 3) VCC = 5VDC, EN = High, TA = 25°C, IF Input = 50MHz at –5dBm, LO Input = 1.95GHz at –10dBm, RF Output Measured at 1900MHz, unless otherwise noted. (Notes 3, 4) IF Input Return Loss With External Matching, ZO = 50Ω 14 LO Input Power dB –15 to –5 dBm LO Input Return Loss With External Matching, ZO = 50Ω 11.5 dB RF Output Return Loss With External Matching, ZO = 50Ω 11.5 dB Conversion Gain –0.7 dB LO to RF Leakage –47 dBm Input 1dB Compression 5.2 dBm 15.5 dBm 51 dBm 14 dB Supply Voltage 4.0 to 5.25 VDC Supply Current 56 65 1 30 Input 3rd Order Intercept Two-Tone, –5dBm/Tone, ∆f = 1MHz Input 2nd Order Intercept Single-Tone, –5dBm SSB Noise Figure Power Supply Requirements: VCC = 5VDC, EN = High, TA = 25°C, unless otherwise noted. Shutdown Current (Chip Disabled) EN = Low Enable Mode Threshold EN = High Disable Mode Threshold EN = Low 3 mA µA VDC 0.5 VDC Turn ON Time (Note 5) 2 µs Turn OFF Time (Note 5) 6 µs 1 µA Enable Input Current EN = 5V Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: External components on the final test circuit are optimized for operation at f RF = 950MHz, f LO = 1GHz and f IF = 50MHz (Figure 2). Note 3: Specifications over the – 40°C to 85°C temperature range are assured by design, characterization and correlation with statistical process controls. Note 4: External components on the final test circuit are optimized for operation at f RF = 1900MHz, f LO = 1.95GHz and f IF = 50MHz (Figure 3). Note 5: Turn On and Turn Off times are based on rise and fall times of RF output envelope from full power to –40dBm with an IF input power of –5dBm. Note 6: Part can be used over a broader range of operating frequencies. Consult factory for applications assistance. 5511i 3 LT5511 U W TYPICAL PERFOR A CE CHARACTERISTICS (950MHz Application) VCC = 5VDC, EN = High , TA = 25°C, IF Input = 50MHz at –5dBm, LO Input = 1GHz at –10dBm, RF Output Measured at 950MHz, unless otherwise noted. For 2-Tone Measurements: 2nd IF Input = 51MHz at –5dBm. (Test Circuit Shown in Figure 2). RF Output Power and 3rd Order Intermodulation vs IF Input Power (Two Input Tones) 0 –10 –20 TA = 25°C –30 –40 TA = 85°C TA = –40°C –50 –20 2 –30 –40 TA = 85°C TA = –40°C –50 –70 –70 –80 –15 –80 –15 –5 –15 5 –10 0 –5 IF INPUT POWER (dBm) IIP2 vs LO Power LO to RF Leakage vs LO Power –5 60 TA = –40°C 2 13 TA = –40°C TA = 25°C 0 –10 –15 –15 TA = 25°C 40 –25 –35 TA = 85°C 9 –55 –20 0 –10 –15 LO POWER (dBm) 30 10 TA = 25°C –5 TA = 85°C 20 TA = –40°C –45 11 TA = 85°C 50 IIP2 (dBm) 15 IIP3 (dBm) 4 LO TO RF LEAKAGE (dBm) 17 TA = –40°C TA = 85°C GAIN (dB) 5 5511 G03 19 6 –2 –20 –10 0 –5 IF INPUT POWER (dBm) 5511 G02 TA = 25°C GAIN TA = 85°C –4 Conversion Gain and IIP3 vs LO Power IIP3 TA = 25°C 0 –1 –3 IM2 5511 G01 8 TA = –40°C 1 –2 TA = 25°C –60 5 3 POUT –60 –10 0 –5 IF INPUT POWER (dBm/TONE) 4 TA = 85°C IM3 POUT, IM2 (dBm) POUT, IM3 (dBm/TONE) TA = 85°C 5 TA = –40°C TA = 25°C 0 TA = –40°C –10 10 POUT TA = 25°C Conversion Gain vs IF Input Power (Single Input Tone) GAIN (dB) 10 RF Output Power and 2nd Order Intermodulation vs IF Input Power (Single Input Tone) –5 0 –20 0 –15 LO POWER (dBm) –10 –5 LO POWER (dBm) 0 5511 G06 5511 G04 5511 G05 2 0 –4 –25 TA = –40°C –35 –6 –45 LO LEAKAGE TA = 25°C –8 IF = 50MHz, LO SWEPT FROM 400MHz TO 1300MHz AT –10dBm –10 300 500 700 900 1100 RF OUTPUT FREQUENCY (MHz) –55 –65 1300 5511 G07 IIP3, IIP2 (dBm) GAIN (dB) TA = 85°C TA = 85°C LO TO RF LEAKAGE (dBm) TA = 25°C 40 30 20 IIP2 18 TA = –40°C TA = 25°C IIP3 TA = 85°C 20 10 TA = 25°C TA = 85°C 50 –15 GAIN –2 60 –5 TA = –40°C SSB Noise Figure vs Output Frequency IIP3 and IIP2 vs Output Frequency NOISE FIGURE (dB) Conversion Gain and LO to RF Leakage vs Output Frequency TA = 25°C TA = –40°C IF = 50MHz, LO SWEPT FROM 400MHz TO 1300MHz AT –10dBm 0 300 500 700 900 1100 RF OUTPUT FREQUENCY (MHz) 16 14 12 1300 5511 G08 IF = 50MHz, LO SWEPT FROM 400MHz TO 1300MHz AT –10dBm 10 300 500 700 900 1100 RF OUTPUT FREQUENCY (MHz) 1300 5511 G09 5511f 4 LT5511 U W TYPICAL PERFOR A CE CHARACTERISTICS (950MHz Application) VCC = 5VDC, EN = High , TA = 25°C, IF Input = 50MHz at –5dBm, LO Input = 1GHz at –10dBm, RF Output Measured at 950MHz, unless otherwise noted. For 2-Tone Measurements: 2nd IF Input = 51MHz at –5dBm. (Test Circuit Shown in Figure 2). Conversion Gain vs Supply Voltage LO and RF Port Return Loss vs Frequency IIP3 and IIP2 vs Supply Voltage 6 0 60 35 TA = 25°C IIP2 4 30 LO PORT –30 2 IIP3 (dBm) GAIN (dB) –20 TA = –40°C TA = 25°C 0 TA = 85°C –50 300 900 700 1100 FREQUENCY(MHz) 500 1300 TA = 85°C 25 20 IIP3 –2 –40 4.2 4.4 4.6 4.8 5.0 5.2 SUPPLY VOLTAGE (V) 4.2 4.4 4.6 4.8 5.0 5.2 SUPPLY VOLTAGE (V) 5511 G11 5511 G10 30 TA = –40°C 10 4.0 5.4 5.6 40 TA = 85°C TA = 25°C 15 –4 4.0 50 TA = –40°C RF PORT IIP2 (dBm) RETURN LOSS (dB) –10 20 10 5.4 5.6 5511 G12 (1.9GHz Application) VCC = 5VDC, EN = High , TA = 25°C, IF Input = 50MHz at –5dBm, LO Input = 1.95GHz at –10dBm, RF Output Measured at 1900MHz, unless otherwise noted. For 2-Tone Measurements: 2nd IF Input = 51MHz at –5dBm. (Test Circuit Shown in Figure 3). RF Output Power and 2nd Order Intermodulation vs IF Input Power (Single Input Tone) RF Output Power and 3rd Order Intermodulation vs IF Input Power (Two Input Tones) 10 0 TA = 25°C TA = 85°C 0 –10 IM3 –20 POUT, IM2 (dBm) POUT, IM3 (dBm/TONE) –10 POUT TA = –40°C –30 TA = –40°C –40 –50 TA = 25°C –70 –80 –15 TA = 85°C 5 5511 G13 4 3 TA = 85°C 2 –30 IM2 –40 –50 –70 –10 0 –5 IF INPUT POWER (dBm/TONE) 5 POUT TA = –40°C –20 –60 –60 TA = 25°C GAIN (dB) 10 Conversion Gain vs IF Input Power (Single Input Tone) –80 –15 1 0 –1 –2 TA = –40°C TA = –40°C TA = 25°C TA = 85°C –3 TA = 85°C –4 TA = 25°C 5 –10 0 –5 IF INPUT POWER (dBm) 5511 G14 –5 –15 –10 0 –5 IF INPUT POWER (dBm) 5 5511 G15 5511i 5 LT5511 U W TYPICAL PERFOR A CE CHARACTERISTICS (1.9GHz Application) VCC = 5VDC, EN = High , TA = 25 ºC, IF Input = 50MHz at –5dBm, LO Input = 1.95GHz at –10dBm. RF Output Measured at 1900MHz, unless otherwise noted. For 2-Tone Measurements: 2nd IF Input = 51MHz at –5dBm. (Test Circuit Shown in Figure 3). Conversion Gain and IIP3 vs LO Input Power 60 –5 50 –15 40 TA = 85°C TA = 25°C 15 TA = 25°C TA = –40°C 2 13 GAIN TA = –40°C 11 0 IIP3 (dBm) GAIN (dB) 4 IIP2 vs LO Input Power 5 TA = 25°C –2 9 TA = 85°C IIP2 (dBm) IIP3 17 LO TO RF LEAKAGE (dBm) 6 LO to RF Leakage vs LO Input Power –25 TA = –40°C –35 TA = 85°C TA = –40°C TA = 85°C 30 20 –45 10 TA = 25°C –4 –25 –55 –25 7 –10 –15 –5 –20 LO INPUT POWER (dBm) 0 –10 –15 –5 –20 LO INPUT POWER (dBm) 5511 G16 TA = 85°C –2 –4 –25 –35 TA = 25°C LO LEAKAGE TA = 85°C –6 TA = –40°C –45 IF = 50MHz, LO SWEPT FROM 1600MHz TO 2350MHz –8 1500 1700 1900 2100 RF OUTPUT FREQUENCY (MHz) 50 IIP3, IIP2 (dBm) –15 TA = 25°C TA = –40°C IIP3 TA = 25°C 20 TA = 85°C 14 IF = 50MHz, LO SWEPT FROM 1600MHz TO 2350MHz 10 1500 1700 1900 2100 RF OUTPUT FREQUENCY (MHz) IF = 50MHz, LO SWEPT FROM 1600MHz TO 2350MHz 0 1500 16 12 TA = –40°C 10 –55 2300 TA = 25°C TA = 25°C 18 40 30 20 IIP2 TA = 85°C NOISE FIGURE (dB) TA = –40°C LO TO RF LEAKAGE (dBm) GAIN (dB) GAIN SSB Noise Figure vs Output Frequency 60 –5 1700 1900 2100 RF OUTPUT FREQUENCY (MHz) 2300 5511 G20 5511 G19 LO and RF Port Return Loss vs Frequency IIP3 and IIP2 vs Supply Voltage 4 30 2 25 60 IIP2 –5 TA = 85°C IIP3 (dBm) GAIN (dB) RF PORT –15 0 TA = –40°C 50 TA = –40°C –10 TA = 25°C TA = 85°C –2 40 20 IIP3 15 TA = 85°C TA = 25°C –20 30 TA = –40°C 2100 1900 1700 FREQUENCY(MHz) 2300 5511 G22 –6 4.0 20 10 –4 –25 –30 1500 TA = 25°C IIP2 (dBm) RETURN LOSS (dB) LO PORT 2300 5511 G21 Conversion Gain vs Supply Voltage 0 0 5511 G18 IIP3 and IIP2 vs Output Frequency 2 –20 –15 –10 –5 LO INPUT POWER (dBm) 5511 G17 Conversion Gain and LO to RF Leakage vs RF Output Frequency 0 0 –25 0 4.2 4.4 4.6 4.8 5.0 5.2 SUPPLY VOLTAGE (V) 5.4 5.6 5511 G23 5 4.0 4.2 4.4 4.6 4.8 5.0 5.2 SUPPLY VOLTAGE (V) 10 5.4 5.6 5511 G24 5511f 6 LT5511 U W TYPICAL PERFOR A CE CHARACTERISTICS Table 1. Typical S-Parameters for the IF, RF and LO Ports (referenced to 50Ω). VCC = 5VDC, EN = High , TA = 25ºC. For each Port Measurement, the other Ports are Terminated as Shown in Figure 2. Frequency Differential IF Port Differential RF Port Differential LO Port Single LO Port (MHz) Mag. Ang. Mag. Ang. Mag. Ang. Mag. Ang. 10 0.65 179.2 – – – – – – 50 0.648 176.2 0.644 –0.8 0.814 –0.6 0.788 –1.0 100 0.645 173.3 0.643 –2.0 0.836 –0.8 0.808 –1.5 150 0.627 170.6 0.642 –3.0 0.804 –1.0 0.780 –2.1 200 0.626 168.5 0.642 –4.0 0.823 –1.6 0.789 –3.0 250 0.619 166.7 0.639 –5.0 0.803 –1.8 0.779 –3.7 300 0.617 165.0 0.635 –6.1 0.815 –2.5 0.773 –4.7 350 0.609 164.1 0.632 –7.2 0.806 –2.9 0.777 –5.9 400 0.597 162.7 0.629 –8.3 0.804 –3.8 0.760 –7.2 450 0.586 162.2 0.626 –9.5 0.805 –4.4 0.776 –8.9 500 0.567 161.3 0.623 –10.7 0.798 –5.2 0.749 –10.0 600 0.527 160.6 0.622 –13.0 0.797 –6.6 0.746 –12.9 700 0.484 160.0 0.620 –15.4 0.799 –7.8 0.750 –15.7 800 0.438 160.6 0.617 –18.0 0.804 –8.9 0.753 –18.0 900 0.451 167.8 0.615 –20.3 0.808 –9.6 0.756 –19.5 1000 0.554 162.3 0.613 –22.4 0.814 –10.2 0.763 –20.5 1100 0.581 150.0 0.611 –24.6 0.817 –10.7 0.765 –21.6 1200 0.574 141.4 0.607 –26.6 0.813 –11.2 0.755 –22.7 1300 0.567 137.2 0.602 –28.6 0.811 –12.2 0.751 –24.7 1400 0.557 135.1 0.594 –30.7 0.805 –13.7 0.743 –27.7 1500 0.540 135.6 0.585 –32.9 0.795 –15.6 0.731 –31.2 1600 0.520 136.5 0.576 –35.3 0.790 –18.0 0.727 –35.3 1700 0.495 136.9 0.567 –37.8 0.789 –20.6 0.726 –39.3 1800 0.462 135.3 0.557 –40.7 0.791 –22.9 0.728 –42.6 1900 0.432 131.0 0.548 –43.8 0.793 –24.8 0.728 –45.0 2000 0.405 124.4 0.540 –47.0 0.795 –26.2 0.728 –46.7 2100 0.390 116.1 0.529 –50.2 0.796 –27.3 0.724 –48.0 2200 0.366 108.1 0.521 –53.9 0.796 –28.4 0.718 –49.8 2300 0.310 110.2 0.513 –57.4 0.790 –29.8 0.703 –52.4 2400 0.417 127.5 0.503 –61.4 0.782 –31.8 0.687 –56.5 2500 0.489 121.5 0.495 –65.3 0.765 –34.8 0.668 –62.7 2600 0.491 122.0 0.486 –69.0 0.748 –38.8 0.656 –70.5 2700 0.472 126.7 0.479 –73.2 0.731 –43.3 0.652 –78.7 2800 0.445 132.0 0.472 –76.8 0.721 –48.3 0.663 –85.9 2900 0.412 138.9 0.468 –80.4 0.720 –52.5 0.680 –91.2 3000 0.375 142.4 0.463 –83.1 0.722 –55.9 0.701 –94.2 5511i 7 LT5511 U U U PI FU CTIO S LO–, LO+ (Pins 1, 16): Differential Inputs for the Local Oscillator Signal. They can also be driven single-ended by connecting one to an RF ground through a DC blocking capacitor. For single-ended drive, use LO+ for the signal input, as this results in less interference from unwanted coupling of the LO signal to other pins. These pins are internally biased to about 1.4V; thus, DC blocking capacitors are required. An impedance transformation is required to match the LO input to 50Ω (or 75Ω). At frequencies below 1.5GHz this input can be resistively matched with a shunt resistor. VCCBIAS (Pin 7): Supply Voltage for the LO Buffer Bias and Enable Circuits. This pin should be connected to VCC and have appropriate RF bypass capacitors. Care should be taken to ensure that RF signal leakage to the VCC line is minimized. NC (Pins 2, 9): Not Connected Internally. Connect to ground for improved isolation between pins. RF –, RF+ (Pins 12, 13): Differential Outputs for the RF Output Signal. An impedance transformation may be required to match the outputs. These pins are also used to connect the mixer to the DC supply through impedancematching inductors, RF chokes or transformer center-tap. Care should be taken to ensure that the RF signal leakage to VCCLO and VCCBIAS is minimized. EN (Pin 10): Chip Enable/Disable. When the applied voltage is greater than 3V, the IC is enabled. When the applied voltage is less than 0.5V, the IC is disabled and the DC current drops to about 1µA. Under no conditions should the voltage on this pin exceed VCC + 0.3V, even at power on. GND (Pins 3, 6, 8,11, 14): Internal Grounds. These pins are used to improve isolation and are not intended as DC or RF grounds for the IC. Connect these pins to ground for best performance. IF+, IF – (Pins 4, 5): Differential Inputs for the IF Signal. A differential signal must be applied to these pins. These pins are internally biased to about 1.2V, and thus require DC blocking capacitors. These pins should be DC isolated from each other for best LO suppression. Imbalances in amplitude or phase between these two signals will degrade the linearity of the mixer. VCCLO (Pin 15): Supply Voltage for the LO Buffer Amplifier. This pin should be connected to VCC and have appropriate RF bypass capacitors. Care should be taken to ensure that RF signal leakage to the VCC line is minimized. GROUND (Backside Contact) (Pin 17): DC and RF Ground Return for the Entire IC. This contact must be connected to a low impedance ground plane for proper operation. W BLOCK DIAGRA NC LO– LO+ 1 16 2 15 VCCLO GND 3 14 GND LO BUFFER IF+ 4 IF – 5 12 RF – BIAS CIRCUITS GND 6 VCCBIAS 13 RF+ 11 GND 10 EN 7 8 GND 17 9 GND NC (BACKSIDE) 5511 BD 5511f 8 LT5511 TEST CIRCUIT LO R1 C1 VCC VCC C4 C5 C7 1 2 IF T1 4 C8 4x 3 R2 C10 1x 5 3 C11 1 R3 C13 4 5 6 7 VCC C17 8 LT5511 LO– LO+ NC VCCLO GND GND 16 15 RF+ IF – 12 RF – GND VCCBIAS EN GND NC L1 13 IF+ GND T2 14 3 4 C12 C15 2 1 11 10 4x 1x C9 RF 5 L2 C14 R5 EN 9 EXPOSED PAD GND 5511F02 Component Value Comments C1, C9, C11, C15 22pF 0402 C5, C7, C17 100pF 0402 C4 0.1µF 0402 C8 220pF 0402 C10, C12, C13 1000pF 0402 C14 1.5pF 0402 L1, L2 6.8nH 0402 62Ω 0402 75Ω, 0.1% 0603 R1 R2, R3 R5 10kΩ 0402 T1 4:1 Coilcraft TTWB-4-A T2 4:1 M/A-Com ETC1.6-4-2-3 Figure 2. Test Circuit and Evaluation Board Schematic for 950MHz Application. 5511i 9 LT5511 TEST CIRCUIT LO C1 VCC C2 L3 C7 1 2 IF T1 4 C8 4x 5 3 3 C10 1x R2 C11 1 C13 R3 4 5 6 7 VCC C17 8 LT5511 LO– NC LO+ VCCLO GND GND IF – RF – 12 GND EN NC T2 14 13 VCCBIAS C4 15 RF+ GND C5 16 IF+ GND VCC L1 3 4 C12 C15 2 1 11 10 4x 1x 5 RF L2 EN 9 5511 F03 Value Comments C1, C9, C11, C15 22pF 0402 C5, C7, C17 100pF 0402 C4 0.1µF 0402 C8 220pF 0402 C10, C12, C13 1000pF 0402 C2 1.2pF 0402 L3 6.8nH 0402 L1, L2 4.7nH 0402 L4 1.8nH 0402 R2, R3 C9 R5 EXPOSED PAD GND Component L4 75Ω, 0.1% 0603 R5 10kΩ 0402 T1 4:1 Coilcraft TTWB-4-A T2 4:1 M/A-Com ETC1.6-4-2-3 Figure 3. Test Circuit and Evaluation Board Schematic for 1.9GHz Application. 5511f 10 LT5511 U W U U APPLICATIO S I FOR ATIO The LT5511 consists of a double-balanced mixer driven by a high-performance, differential, limiting LO buffer. The mixer has been optimized for high linearity and high signal level operation. The LT5511 is intended for applications with LO frequencies of 0.4GHz to 2.7GHz and IF input frequencies from 10MHz to 300MHz, but can be used at other frequencies with excellent results. The LT5511 can be used in applications using either a low side or high side LO. IF Input Port The IF+ and IF– pins are the differential inputs to the mixer. These inputs drive the emitters of the switching transistors, and thus have a low impedance. The DC current through these transistors is set by external resistors from each IF pin to ground. The typical internal voltage on the emitters is 1.2V; thus, the current through each IF pin is approximately: IIF = 1.2/RIF LO Input Port The LO buffer on the LT5511 consists of differential high speed amplifiers and limiters that are designed to drive the mixer quad to achieve high linearity and performance at high IF input signal levels. The LO+ and LO– pins are the differential inputs to the LO buffer. Though the LO signal can be applied differentially, the LO buffer performs well with only one input driven, thus eliminating the need for a balun. In this case, a capacitor should be connected between the unused LO input pin and ground. The LO pins are biased internally to about 1.4V, and thus must be DC isolated from the external LO signal source. The LO input should be matched to 50Ω. The impedance match can be accomplished through the use of a reactive impedance matching network. However, for lower LO frequencies (below about 1.5GHz), an easier approach is to use a shunt 62Ω resistor to resistively match the port. (The resistor must be DC isolated from the LO input pin). This method is broadband and requires LO power levels of only –10dBm. At higher frequencies, a better match can be realized with reactive components. Transmission lines and parasitics should be considered when designing the matching circuits. Typical S-parameter data for the LO input is included in Table 1 to facilitate the design of the matching network. RIF is the value of the external resistors to ground. Best performance is obtained when the IF inputs are perfectly balanced and 0.1% tolerance resistors are recommended here. The LT5511 has been characterized with 75Ω resistors on each of the IF inputs. The IF signal to the mixer must be differential. To realize this, an RF balun transformer or lumped element balun can be used. The RF transformer is recommended, as it is easier to realize broadband operation, and also does not have the component sensitivity issues of a lumped element balun. The differential input impedance of the IF input is approximately 12.5Ω; therefore, a 4:1 impedance transformation is required to match to 50Ω. Selecting a transformer with this impedance ratio will reduce the amount of additional components required, as the full impedance transformation is realized by the transformer. DC-isolating transformers or transmission-line transformers can be used, as could lumped element transformation networks. Because the IF ports are internally biased, they must be DC isolated from the IF source. Additionally, IF+ and IF– must be DC isolated from each other in order to maintain good LO suppression. 5511i 11 LT5511 U W U U APPLICATIO S I FOR ATIO On the evaluation board (Figure 4), 1nF DC-blocking capacitors are used on the IF input pins. A 220pF capacitor on the 50Ω source side of the input balun is used to tune out the excess inductance to improve the match at 50MHz. To shift the match higher in frequency, this capacitor value should be reduced. optimum performance. These pins are biased at the supply voltage, which can be applied through the center tap of the output transformer. (The center tap should be RF bypassed for best performance). A pair of series inductors can be used to match RF+ and RF– to the high impedance (200Ω) side of a 4:1 balun. RF Output Port The RF outputs, RF+ and RF–, are internally connected to the collectors of the mixer switching transistors. These differential output signals should be combined externally through an RF balun transformer or 180° hybrid to achieve The output balun has a significant impact on the performance of the mixer. A broadband balun provides better rejection of the 2fLO spur. If the level of that spur is not critical, a less expensive and smaller balun can be used. The amplitude and phase balances of the balun will affect the LO suppression. (4a) Top Layer Silkscreen (4b) Top Layer Metal Figure 4. Evaluation Board Layout. 5511f 12 LT5511 U U W U APPLICATIO S I FOR ATIO SPECTRUM ANALYZER POWER SUPPLY RFOUT GND 10dB PAD LOIN LO SIGNAL GENERATOR 3 T2 E3 LT5511 IC E2 T1 E1 IFIN DMM SW1 RF SIGNAL GENERATOR 1 POWER SUPPLY + RF SIGNAL GENERATOR 2 (OR PULSE GENERATOR FOR TURN-ON AND TURN-OFF MEASUREMENTS) 5511 F05 Figure 5. Test Set-Up for Mixer Measurements 5511i 13 LT5511 U TYPICAL APPLICATIO S LO C1 VCC C11 L1 C7 1 2 C10 L6 IF + (50Ω) 3 R2 C2 C13 L7 IF – (50Ω) R3 C18 NC LO+ VCCLO GND GND 15 14 IF+ RF+ 13 5 IF – RF – 12 6 8 GND GND VCCBIAS GND EN NC C4 16 4 7 VCC LT5511 LO– VCC C5 3 TL1 C12 11 10 9 C9 5 EN R5 EXPOSED PAD GND Component Value 5511 F06 Comments C1, C9 22pF 0402 C5, C7, C18 100pF 0402 C4 0.1µF 0402 C2 12pF 0402 1000pF 0402 C11 1pF 0402 L1 5.2nH 0402 L6, L7 5.6nH 0402 R2, R3 75Ω, 0.1% 0603 C10, C12, C13 RF 1 2 4 TL2 T2 R5 10kΩ 0402 T2 1:1 MURATA LDB15C500A2400 ZO = 80Ω L = 16° AT 2.4GHz Transmission Lines TL1, TL2 Figure 6. Test Circuit Schematic for 2.4GHz RF Application with 300MHz IF Input Frequency 5511f 14 LT5511 U TYPICAL APPLICATIO S IIP3 and IIP2 vs Output Frequency (Figure 6) Conversion Gain and LO to RF Leakage vs Output Frequency (Figure 6) –8 50 –1 –13 45 –2 –18 40 –23 GAIN (dB) –3 –4 –5 –6 –28 fIF1 = 300MHz AT –8dBm fIF2 = 301MHz AT –8dBm PLO = –10dBm fLO SWEPT FROM 1900MHz TO 2300MHz –33 –38 –43 –7 –8 –48 LO LEAKAGE –53 –9 –10 2200 2300 2500 2400 RF OUTPUT FREQUENCY (MHz) –58 2600 IIP2 35 IIP3, IIP2 (dBm) GAIN LO TO RF LEAKAGE (–dBm) 0 30 25 20 fIF1 = 300MHz AT –8dBm fIF2 = 301MHz AT –8dBm PLO = –10dBm fLO SWEPT FROM 1900MHz TO 2300MHz IIP3 15 10 5 0 2200 2300 2500 2400 RF OUTPUT FREQUENCY (MHz) 5511 F06a 2600 5511 F06a 5511i 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 LT5511 U PACKAGE DESCRIPTIO FE Package 16-Lead Plastic TSSOP (4.4mm) (Reference LTC DWG # 05-08-1663) Exposed Pad Variation BA 4.90 – 5.10* (.193 – .201) 2.74 (.108) 2.74 (.108) 16 1514 13 12 1110 6.60 ±0.10 9 2.74 (.108) 4.50 ±0.10 SEE NOTE 4 2.74 6.40 (.108) BSC 0.45 ±0.05 1.05 ±0.10 0.65 BSC 1 2 3 4 5 6 7 8 RECOMMENDED SOLDER PAD LAYOUT 1.10 (.0433) MAX 4.30 – 4.50* (.169 – .177) 0° – 8° 0.09 – 0.20 (.0036 – .0079) 0.65 (.0256) BSC 0.45 – 0.75 (.018 – .030) NOTE: 1. CONTROLLING DIMENSION: MILLIMETERS MILLIMETERS 2. DIMENSIONS ARE IN (INCHES) 3. DRAWING NOT TO SCALE 0.195 – 0.30 (.0077 – .0118) 0.05 – 0.15 (.002 – .006) FE16 (BA) TSSOP 0203 4. RECOMMENDED MINIMUM PCB METAL SIZE FOR EXPOSED PAD ATTACHMENT *DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.150mm (.006") PER SIDE RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT5500 1.8GHz to 2.7GHz Receiver-Front End 1.8V to 5.25V Supply, Dual-Gain LNA, Mixer, LO Buffer LT5502 400MHz Quadrature IF Demodulator with RSSI 1.8V to 5.25V Supply, 70MHz to 400MHz IF, 84dB Limiting Gain, 90db RSSI Range LT5503 1.2GHz to 2.7GHz Direct IQ Modulator and Upconverting Mixer 1.8V to 5.25V Supply, Four-Step RF Power Control, 120MHz Modulation Bandwidth LT5504 800MHz to 2.7GHz Measuring Receiver 80dB Dynamic Range, Temperature Compensated, 2.7V to 5.5V Supply LTC®5505 RF Power Detectors with >40dB Dynamic Range 300MHz to 3GHz, Temperature Compensated, 2.7V to 6V Supply LT5506 500MHz Quadrature Demodulator with VGA 1.8V to 5.25V Supply, –4dB to 57dB Linear Power Gain LT5507 100kHz to 1GHz RF Power Detector 48dB Dynamic Range, Temperature Compensated, 2.7V to 6V Supply LTC5508 300MHz to 7GHz RF Power Detector >40dB Dynamic Range, SC70 Package LT5512 High Signal Level Down Converting Mixer Up to 3GHz, 20dBm IIP3, Integrated LO Buffer 5511f 16 Linear Technology Corporation LT/TP 0503 1K • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2001