LT5521 Very High Linearity Active Mixer FEATURES DESCRIPTIOU n Wideband Output Frequency Range to 3.7GHz The LT®5521 is a very high linearity mixer optimized for n +24.2dBm IIP3 at 1.95GHz RF Output low distortion and low LO leakage applications. The chip n Low LO Leakage: –42dBm includes a high speed LO buffer with single-ended input n Integrated LO Buffer: Low LO Drive Level and a double-balanced active mixer. The LT5521 requires n Single-Ended LO Drive only –5dBm LO input power to achieve excellent distor- n Wide Single Supply Range: 3.15V to 5.25V tion and noise performance, while reducing external drive n Double-Balanced Active Mixer circuit requirements. The LO buffer is internally 50W n Shutdown Function matched for wideband operation. n 16-Lead (4mm · 4mm) QFN Package With a 250MHz input, a 1.7GHz LO and a 1.95GHz output frequency, the mixer has a typical IIP3 of +24.2dBm, APPLICATIOU S –0.5dB conversion gain and a 12.5dB noise figure. The LT5521 offers exceptional LO-RF isolation, greatly n Cellular, W-CDMA, PHS and UMTS Infrastructure reducing the need for output filtering to meet LO suppres- n Cable Downlink Infrastructure sion requirements. n Wireless Infrastructure n Fixed Wireless Access Equipment The device is designed to work over a supply voltage range n High Linearity Mixer Applications from 3.15V to 5.25V. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATIOU Fundamental, 3rd Order LO INPUT Intermodulation Distortion –5dBm vs Input Power 6.8pF 20 LO GND 0 INPUITF BPF 1110nnpFFF 1:1 611.1810p0ΩΩF IINN+–BIASEN VCC VCCOOVUUCTTC+– 22..77nnHH15nVF DC 4:1 8822ppFF BPF PA ROFUTPUT OUTPUT POWER (dBm)––––62840000 IMP3FUNDfffPILRFLOF O= == =2 11 5–..0975M5GdGBHHHmzzz 1µF –100 TA = 25°C –14–12–10 –8 –6 –4 –2 0 2 4 6 5521 TA01 PIN (dBm) 5521 TA02 5521f 1

LT5521 ABSOLUTE WMAXIWMUWM RATINUGS PACKAGE/ORDER IUNFORWMATIOUN (Note 1) Power Supply Voltage ........................................... 5.5V ORDER PART TOP VIEW Enable Voltage............................... –0.2V to VCC + 0.2V ND O ND ND NUMBER LO Input Power ................................................+10dBm G L G G 16 15 14 13 LT5521EUF LO Input DC Voltage..................................... 0V to 1.5V GND 1 12 OUT+ IF Input Power................................................. +10dBm IN+ 2 11 GND 17 Difference Voltage Across Output Pins................ – 1.5V IN– 3 10 GND Maximum Pin 2 or Pin 3 Current......................... 34mA GND 4 9 OUT– UF PART Operating Ambient Temperature Range..–40(cid:176) C to 85(cid:176) C 5 6 7 8 MARKING Storage Temperature Range................. –65(cid:176) C to 125(cid:176) C EN VCC VCC VCC Maximum Junction Temperature..........................125(cid:176) C 16-LEAD (4mUmF P· A 4CmKmAG) EPLASTIC QFN 5521 TJMAX = 125(cid:176)C, q JA = 37(cid:176)C/W EXPOSED PAD (PIN 17) IS GND MUST BE SOLDERED TO PCB Consult LTC Marketing for parts specified with wider operating temperature ranges. DC ELECTRICAL CHARACTERISTICS V = 5V, EN = 2.9V, T = 25(cid:176) C unless otherwise noted. CC A Test circuit shown in Figure 1. (Note 2) PARAMETER CONDITIONS MIN TYP MAX UNITS Supply Voltage 3.15 5.25 V Supply Current 82 98 mA Shutdown Current EN = 0.2V 20 100 m A Enable (EN) Low = Off, High = On Enable Mode EN = High 2.9 V Disable Mode EN = Low 0.2 V Enable Current EN = 5V 137 m A Shutdown Enable Current EN = 0.2V 0.1 m A Turn-On Time (Note 3) 200 ns Turn-Off Time (Note 4) 200 ns LO Voltage (Pin 15) Internally Biased 0.96 V Input Voltage (Pins 2, 3) V = 5V, Internally Biased 2.20 V CC V = 3.3V, Internally Biased 0.46 V CC AC ELECTRICAL CHARACTERISTICS V = 5V, EN = 2.9V, T = 25(cid:176) C unless otherwise noted. CC A Test circuit shown in Figure 1. (Note 2) PARAMETER CONDITIONS MIN TYP MAX UNITS LO Frequency Range 10 to 4000 MHz Input Frequency Range 10 to 3000 MHz Output Frequency Range 10 to 3700 MHz LO Input Power –5 1 dBm LO Return Loss Z = 50W , f = 1700MHz 12 dB O LO Output Return Loss Requires Matching 12 dB Input Return Loss (Pins 2, 3) Requires Matching 15 dB 5521f 2

LT5521 AC ELECTRICAL CHARACTERISTICS V = 5V, EN = 2.9V, f = 250MHz, P = –7dBm, f = 1700MHz, CC IF IF LO P = –5dBm, f = 1950MHz, T = 25(cid:176) C. Test circuit shown in Figure 1. LO RF A PARAMETER CONDITIONS MIN TYP MAX UNITS Conversion Gain –0.5 dB Conversion Gain Variation vs Temperature –0.009 dB/(cid:176) C Input P1dB +10 dBm Single-Side Band Noise Figure 12.5 dB IIP3 Two Tones, D f = 5MHz, P = –7dBm/Tone +24.2 dBm IF IF IIP2 (Note 6) Two Tones, D f = 5MHz, P = –7dBm/Tone, +49 dBm IF IF f + f + f LO IF1 IF2 LO-RF Leakage –42 dBm LO-IF Leakage –40 dBm V = 5V, EN = 2.9V, f = 44MHz, P = –7dBm, f = 1001MHz, P = –5dBm, f = 1045MHz, T = 25(cid:176) C. CC IF IF LO LO RF A PARAMETER CONDITIONS MIN TYP MAX UNITS Conversion Gain –0.5 dB Conversion Gain Variation vs Temperature –0.012 dB/(cid:176) C Input P1dB +10 dBm Single-Side Band Noise Figure 12.8 dB IIP3 Two Tones, D f = 5MHz, P = –7dBm/Tone +24.5 dBm IF IF IIP2 (Note 6) Two Tones, D f = 5MHz, P = –7dBm/Tone, +49 dBm IF IF f + f + f LO IF1 IF2 LO-RF Leakage –38 dBm LO-IF Leakage –59 dBm V = 3.3V, EN = 2.9V, f = 250MHz, P = –7dBm, f = 1700MHz, P = –5dBm, f = 1950MHz, T = 25(cid:176) C. (Note 5) CC IF IF LO LO RF A PARAMETER CONDITIONS MIN TYP MAX UNITS Conversion Gain –0.5 dB Conversion Gain Variation vs Temperature –0.013 dB/(cid:176) C Input P1dB +11 dBm Single-Side Band Noise Figure 13.5 dB IIP3 Two Tones, D f = 5MHz, P = –7dBm/Tone +25.8 dBm IF IF IIP2 (Note 6) Two Tones, D f = 5MHz, P = –7dBm/Tone, +50 dBm IF IF f + f + f LO IF1 IF2 LO-RF Leakage –36 dBm LO-IF Leakage –60 dBm Note 1: Absolute Maximum Ratings are those values beyond which the life Note 4: Interval from the falling edge of the Enable signal to a 20dB drop of a device may be impaired. in the RF output power. Note 2: Specifications over the –40(cid:176) C to 85(cid:176) C temperature range are Note 5: R1 = R7 = 22.6W , Z1 = Z7 = 100nH. assured by design, characterization and correlation with statistical process Note 6: Second harmonic distortion measured at f + f + f . LO IF1 IF2 controls. Note 3: Interval from the rising edge of the Enable input to the time when the RF output is within 1dB of its steady-state output. 5521f 3

LT5521 TYPICAL DC PERFORW AU CE CHARACTERISTICS Test circuit shown in Figure 1. Supply Current vs Supply Voltage Supply Current vs Supply Voltage (5V Application) (3.3V Application) 100 110 95 100 90 85°C 85°C 90 85 A) 25°C A) 25°C (mC 80 (mC 80 IC IC –40°C 75 –40°C 70 70 60 65 60 50 4.7 4.8 4.9 5.0 5.1 5.2 5.3 3.1 3.2 3.3 3.4 3.5 VCC (V) VCC (V) 5521 G01 5521 G02 TYPICAL AC PERFORW AU CE CHARACTERISTICS f = 1700MHz, f = 250MHz, f = 1950MHz, P = –5dBm, V = 5V, EN = 2.9V, T = 25(cid:176) C, unless otherwise noted. Test circuit LO IF RF LO CC A shown in Figure 1 is tuned for 1.95GHz output frequency and V = 5V. CC Fundamental, 2nd and 3rd Order Intermodulation Distortion Conversion Gain and IIP3 vs Input Power Conversion Gain vs Input Power vs RF Frequency 20 1.0 10 25 85°C 0 2–54°0C°C PFUND 0.5 –40°C 8 IIP3 24 dBm)–20 IM3 0 25°C 6 23 UT POWER (–40 IM2 G (dB)C––01..50 85°C G (dB)C 42 82–554°°0CC°C 2221 IIP3 (dBm) TP–60 GC U –1.5 0 20 O IM2 –80 –2.0 –2 19 IM3 –100 –2.5 –4 18 –14–12–10 –8 –6 –4 –2 0 2 4 6 –25 –20 –15 –10 –5 0 5 10 15 1750 1850 1950 2050 2150 PIN (dBm) PIN (dBm) RFOUT (MHz) 5521 G03 5521 G04 5521 G05 5521f 4

LT5521 TYPICAL AC PERFORW AU CE CHARACTERISTICS f = 1700MHz, f = 250MHz, f = 1950MHz, LO IF RF P = –5dBm, V = 5V, EN = 2.9V, T = 25(cid:176) C, unless otherwise noted. Test circuit shown in Figure 1 is tuned for 1.95GHz output LO CC A frequency and V = 5V. CC Conversion Gain, IIP3 and Noise Conversion Gain and IIP3 LO-RF Leakage vs LO Frequency Figure vs Supply Voltage vs LO Power –36 10 30 10 25 –38 8 IIP3 25 IIP 8 24 –40°C 3 (d IIP3 LEAKAGE (dBm)–––444204 85°2C5°C G (dB)C 462 NF 82–554°°0CC°C 121500 Bm) AND NOISE FIG G (dB)C426 82–554°°0CC°C GC 222213IIP3 (dBm) U 0 20 GC RE –46 0 5 (dB –2 19 ) –48 –2 0 –4 18 1500 15501600165017001750180018501900 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 –25 –20 –15 –10 –5 0 5 10 LO FREQUENCY (MHz) VCC (V) LO POWER (dBm) 5521 G06 5521 G07 5521 G08 LO-RF Leakage vs LO Power LO-RF Leakage vs Supply Voltage Noise Figure vs LO Power –32 –34 20 –34 –36 19 18 –36 –38 m)–38 m) –40°C B) 17 LO LEAKAGE (dB–––444204 –40°8C5°C LO LEAKAGE (dB –––444240 8255°°CC NOISE FIGURE (d 11116453 85°C25°C 25°C –46 –40°C –46 12 –48 –48 11 –50 –50 10 –25 –20 –15 –10 –5 0 5 10 4.7 4.8 4.9 5.0 5.1 5.2 5.3 –20 –15 –10 –5 0 5 LO POWER (dBm) VCC (V) LO POWER (dBm) 5521 G09 5521 G10 5521 G11 Low Side LO (LS) and High Side Low Side LO (LS) and High Side LO (HS) Comparison: Conversion LO (HS) Comparison: Noise Figure Gain and IIP3 vs RF Frequency vs RF Frequency 10 26 13.5 LS: R1 = R7 = 110Ω 8 LS IIP3 24 13.3 HS: R1 = R7 = 121Ω 13.1 fIF = 250MHz HS 6 LS: R1 = R7 = 110Ω 22 dB) 12.9 G (dB)C 42 HfIFS =: R215 0=M RH7z = 121Ω 2108 IIP3 (dBm) SE FIGURE ( 111222...735 HS OI LS 0 GC LS 16 N 12.1 HS 11.9 –2 14 11.7 –4 12 11.5 1750 1850 1950 2050 2150 170017501800 18501900 195020002050 2100 RFOUT (MHz) RFOUT (MHz) 5521 G13 5521 G14 5521f 5

LT5521 TYPICAL AC PERFORW AU CE CHARACTERISTICS f = 1001MHz, f = 44MHz, f = 1045MHz, LO IF RF P = –5dBm, V = 5V, EN = 2.9V, T = 25(cid:176) C, unless otherwise noted. Test circuit shown in Figure 1 is tuned for 1.045GHz output LO CC A frequency. Fundamental, 2nd and 3rd Order Intermodulation Distortion Conversion Gain and IIP3 vs Input Power Conversion Gain vs Input Power vs RF Frequency, Fixed IF 20 1.0 10 25 0 PFUND 0.5 –40°C 8 24 IM3 IIP3 m)–20 0 6 23 T POWER (dB––4600 IM2 IM2 G (dB)C––01..50 2855°°CC G (dB)C 42 82–554°°0CC°C 2221 IIP3 (dBm U ) TP GC U–80 –1.5 0 20 O IM3 –100 85°C –2.0 –2 19 25°C –40°C –120 –2.5 –4 18 –14–12–10 –8 –6 –4 –2 0 2 4 6 –25 –20 –15 –10 –5 0 5 10 15 920 970 1020 1070 1120 1170 INPUT POWER (dBm) PIN (dBm) RFOUT (MHz) 5521 G15 5521 G16 5521 G17 Conversion Gain, IIP3 and Noise Conversion Gain and IIP3 LO-RF Leakage vs LO Frequency Figure vs Supply Voltage vs LO Power –32 10 26 10 25 –33 8 IIP3 22 IIP 8 IIP3 24 –34 85°C 3 (d –35 6 25°C 18 Bm 6 23 LEAKAGE (dBm)––––33338697 –2450°°CC G (dB)C 42 NF –40°C 1140 ) AND NOISE FIGU G (dB)C420 82–554°°0CC°C GC 222210IIP3 (dBm) ––4401 85°C 0 GC 6 RE (dB) –2 19 –42 –2 2 –4 18 850 900 950 1000 1050 1100 1150 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 –25 –20 –15 –10 –5 0 5 10 LO FREQUENCY (MHz) VCC (V) LO POWER (dBm) 5521 G18 5521 G19 5521 G20 LO-RF Leakage vs LO Power LO-RF Leakage vs Supply Voltage –30 –30 –32 –32 m) –34 m) –34 B B E (d –40°C E (d –36 –40°C AKAG –36 25°C AKAG –38 25°C E E LO L –38 85°C LO L –40 85°C –40 –42 –42 –44 –25 –20 –15 –10 –5 0 5 10 4.6 4.7 4.8 4.9 5.0 5.1 5.2 5.3 5.4 LO POWER (dBm) VCC (V) 5521 G21 5521 G22 5521f 6

LT5521 TYPICAL AC PERFORW AU CE CHARACTERISTICS f = 1001MHz, f = 44MHz, f = 1045MHz, LO IF RF P = –5dBm, V = 5V, EN = 2.9V, T = 25(cid:176) C, unless otherwise noted. Test circuit shown in Figure 1 is tuned for 1.045GHz output LO CC A frequency. Low Side LO (LS) and High Side Low Side LO (LS) and High Side LO (HS) Comparison: Conversion LO (HS) Comparison: Noise Figure Noise Figure vs LO Power Gain and IIP3 vs RF Frequency vs RF Frequency 20 4 25 14.0 fIF = 44MHz fIF = 44MHz 19 LS 3 24 13.5 18 IIP3 HS SE FIGURE (dB) 11116457 85°C 25°C G (dB)C 12 2223IIP3 (dBm) SE FIGURE (dB)1132..05 HLSS NOI 13 –40°C 0 GC LS 21 NOI12.0 12 HS –1 20 11.5 11 10 –2 19 11.0 –20 –15 –10 –5 0 5 940 990 1040 1090 1140 945 985 1025 1065 1105 1145 LO POWER (dBm) RFOUT (MHz) RFOUT (MHz) 5521 G23 5521 G34 5521 G24 f = 1.7GHz, f = 250MHz, f = 1.95GHz, P = –5dBm, V = 3.3V, EN = 2.9V, T = 25(cid:176) C, unless otherwise noted. Test circuit LO IF RF LO CC A shown in Figure 1 is tuned for 1.95GHz output frequency and V = 3.3V. CC Conversion Gain and IIP3 P , IM3 and IM2 vs Input Power Conversion Gain vs Input Power vs RF Frequency OUT 20 0.5 10 27 –40°C 8 25 0 POUT 0 IIP3 m) IM3 6 23 dB–20 –0.5 25°C UT POWER (–40 IM2 G (dB)C–1.0 85°C G (dB)C 42 82–554°°0CC°C 2119 IIP3 (dBm) TP–60 –1.5 GC OU IM2 0 17 –80 85°C –2.0 –2 15 25°C IM3 –40°C –100 –2.5 –4 13 –14–12–10 –8 –6 –4 –2 0 2 4 6 –20 –15 –10 –5 0 5 10 175018001850190019502000205021002150 PIN (dBm) PIN (dBm) RFOUT (MHz) 5521 G25 5521 G26 5521 G27 5521f 7

LT5521 TYPICAL AC PERFORW AU CE CHARACTERISTICS f = 1.7GHz, f = 250MHz, f = 1.95GHz, P LO IF RF LO = –5dBm, V = 3.3V, EN = 2.9V, T = 25(cid:176) C, unless otherwise noted. Test circuit shown in Figure 1 is tuned for 1.95GHz output CC A frequency and V = 3.3V. CC Conversion Gain, IIP3 and Noise Conversion Gain and IIP3 LO-RF Leakage vs LO Frequency Figure vs Supply Voltage vs LO Power –32 10 27 85°C 25°C 8 24 –33 –40°C IIP3 IIP 8 25 3 LEAKAGE (dBm) ––––33336475 G (dB)C462 82–554°°0CC°C NF 121602 (dBm) AND NOISE FIG G (dB)C462 82–554°°0CC°C GC IIP3 212193IIP3 (dBm) U 0 17 ––3389 0 GC 8 RE (dB) –2 15 –40 –2 4 –4 13 150015501600165017001750180018501900 3.10 3.15 3.20 3.25 3.30 3.35 3.40 3.45 3.50 –25 –20 –15 –10 –5 0 5 10 LO FREQUENCY (MHz) VCC (V) LO POWER (dBm) 5521 G28 5521 G31 5521 G29 LO-RF Leakage vs LO Power Noise Figure vs LO Power LO Leakage vs Supply Voltage –30 22 –20 –23 –32 20 85°C –26 LO LEAKAGE (dBm) ––––33436804 –40°C 25°C NOISE FIGURE (dB) 111468 8255°°CC LO LEAKAGE (dBm)–––––3343282159 –8450°°CC 25°C –44 12 –40°C –42 –47 –44 10 –50 –25 –20 –15 –10 –5 0 5 10 –20 –15 –10 –5 0 5 3.0 3.1 3.2 3.3 3.4 3.5 3.6 LO POWER (dBm) LO POWER (dBm) VCC (V) 5521 G30 5521 G32 5521 G33 PIU FUU CTIOU S GND (Pins 1, 4, 10, 11, 13, 14, 16): Ground. These pins V (Pins 6, 7, 8): Power Supply Pins. Total current draw CC are internally connected to the Exposed Pad for improved for these three pins is 40mA. isolation. They should be connected to RF ground on the OUT+, OUT– (Pins 12, 9): RF Output Pins. These pins must printed circuit board, and are not intended to replace the have a DC connection to the supply voltage (see Applica- primary grounding through the backside of the package. tions Information). These pins draw 20mA each. External IN+, IN– (Pins 2, 3): Differential Input Pins. Each pin matching is required. requires a resistive DC path to ground. See Applications LO (Pin 15): Local Oscillator Input. This input is internally Information for choosing the resistor value. External match- DC biased to 0.96V. Input signal must be AC coupled. ing is required. Exposed Pad (Pin 17): Circuit Ground Return for the EN (Pin 5): Enable Input Pin. The enable voltage should be Entire IC. For best performance, this pin must be soldered at least 2.9V to turn the chip on and less than 0.2V to turn to the printed circuit board. the chip off. 5521f 8

LT5521 BLOCK DIAGRAW 17 16 15 14 13 EXPOSED GND LO GND GND PAD GND OUT+ 1 12 IN+ GND 2 11 IN– GND 3 10 GND OUT– 4 9 BIAS EN VCC VCC VCC 5 6 7 8 5521 BD TEST CIRCUITS LOIN C1 0.017" er = 4.4 RGFND 50Ω 0.062" DC 0.017" Z1 GND OPT 16 15 14 13 GND L0 GND GND T2 C3 5I0FΩIN C2 Z3 T1 R1 12 GINN+D LT5521 OGUNTD+ 1121 CL14 R50FΩOUT Z14 C13 3 IN– EXPOSED GND 10 C12 4 GND PAD (17) OUT– 9 L2 C6 R7 EN VCC VCC VCC Z7 5 6 7 8 OPT R8 VCC C11 EN 5521 F01 Figure 1. Demonstration Board Schematic Table 1. Demonstration Board Bill of Materials1, 2 fIF = 250MHz, fRF = 1.95GHz fIF = 44MHz, fRF = 1.045GHz fIF = 250MHz, fRF = 1.95GHz REF fLO = 1.7GHz, VCC = 5V fLO = 1.001GHz, VCC = 5V fLO = 1.7GHz, VCC = 3.3V R1, R7 110Ω, 1% 110Ω, 1% 22.6Ω, 1% Z14 10pF 120nH 10pF Z3 0Ω 150pF 0Ω L1, L2 2.7nH 10nH 2.7nH T1 M/A-COM MABACT00103 M/A-COM MABACT00103 M/A-COM MABACT00103 T2 M/A-COM ETC1.6-4-2-3 M/A-COM ETC1.6-4-2-3 M/A-COM ETC1.6-4-2-3 C1, C13 6.8pF 27pF 6.8pF C3 82pF 3.9pF 82pF C12 82pF 1nF 82pF C2, C4, C6 1nF 1nF 1nF C11 1µF 1µF 1µF Z1, Z7 0Ω 0Ω 100nH THIS COMPONENT CAN BE REPLACED BY PCB TRACE ON FINAL APPLICATION R8 10k 10k 10k Note 1: Tabulated values are used for characterization measurements. Note 2: Components shown on the schematic are included for consistency with the demo board. If no value is shown for the component, the site is unpopulated. Note 3: T1 also M/A-COM ETC1-1-13 and Sprague Goodman GLSW4M202. These alternative transformers have been measured and have similar performance. 5521f 9

LT5521 APPLICATIOU S IU FORW ATIOU The LT5521 is a high linearity double-balanced active 0 mixer. The chip consists of a double-balanced mixer core, –5 a high performance LO buffer and associated bias and enable circuitry. The chip is designed to operate with a –10 B) d supply voltage ranging from 3.15V to 5.25V. S ( –15 S O Table 2. Port Impedance N L –20 R U FREQUENCY DIFFERENTIAL DIFFERENTIAL SINGLE-ENDED ET –25 R (MHz) INPUT OUTPUT LO F I –30 50 19.8 + j0.7 282.2 – j8.4 49.9 + j0.1 –35 100 20.1 + j2.0 282.3 – j20.8 49.8 + j0.3 –40 300 18.2 + j5.3 262.3 – j55.1 49.2 + j0.9 100 150 200 250 300 350 400 FREQUENCY (MHz) 600 15.2 + j16.8 231.4 – j67.0 47.7 + j2.0 5521 F03 1000 14.5 + j28.1 215.0 – j124.5 45.3 + j2.8 Figure 3. IF Input Return Loss 1500 20.5 + j42.3 109.5 – j158.0 43.3 + j2.8 2000 48.2 + j26.8 52.9 – j92.1 43.0 + j3.3 For input frequencies above 100MHz, a broadband im- 2300 18.2 + j29.4 61.6 – j74.2 43.4 + j4.6 pedance matching tranformer with a 1:1 impedance ratio 3200 22.4 + j125.1 14.2 – j27.5 44.6 + j14.0 is recommended. Table 3 provides the component values 3500 27.9 – j4.4 42.4 + j17.9 necessary to match various IF frequencies using the M/A- 4000 42.8 – j16.0 38.6 + j22.8 COM CT0010 transformer (T1, Figure 1). Table 3. Component Values for Input Matching Using the Signal Input Interface M/A-COM CT0010 IF C2 Z14 Z3 Figure 2 shows the signal inputs of the LT5521. The signal 44MHz 1000pF 120nH 150pF input pins are connected to the common emitter nodes of the mixer quad differential pairs. The real part of the 95MHz 820pF 33pF 27nH differential IN+/IN– impedance is 20W . The mixer core 120MHz 1000pF 27pF 18nH current is set by external resistors R1 and R7. Setting their 150MHz 330pF 22pF 10nH values at 110W , the nominal DC voltage at the inputs is 170MHz 330pF 18pF 6.8nH 2.2V with V = 5V. Figure 3 shows the input return loss 250MHz 82pF 10pF 0W CC for a matched input at 250MHz. 300MHz 15pF 3.9pF 0W 435MHz 8.2pF 0.5pF 0W 520MHz 6.8pF Unused 0W Z1 OPT Below 100MHz, the Mini-Circuits TCM2-1T or the Pulse LT5521 C2 R1 5I0FΩIN Z3 T1 2 IN+ CcoXn2f0ig4u5r aatrieo nb eist tsehr ocwhoni icne Fsi gfourr ea 4w. iTdheer sinepriuets m1naFtc cha.p Tahciis- 1:1 C13 tors maintain differential symmetry while providing DC Z14 VCC isolation between the inputs. This helps to improve LO IN– suppression. 3 C6 R7 Shunt capacitor C13 (Figure 2) is an optional capacitor 1nF across the input pins that significantly improves LO sup- Z7 5521 F02 OPT pression. Although this capacitor is optional, it is impor- tant to regulate LO suppression, mitigating part-to-part Figure 2. Signal Input with External Matching variation. This capacitor should be optimized depending 5521f 10

LT5521 APPLICATIOU S IU FORW ATIOU Operation at Reduced Supply Voltage LT5521 C2 1nF R1 5I0FΩIN T1 2 IN+ External resistors R1 and R7 (Figure 2) set the current 2:1 through the mixer core. For best distortion performance, these resistors should be chosen to maintain a total of C13 VCC 40mA through the mixer core (20mA per side). At 5V 1nF IN– supply, R1 and R7 should be 110W . Table 5 shows 3 recommended values for R1 and R7 at various supply R7 voltages. Caution: Using values below the recommended 5521 F04 resistance can adversely affect operation or damage the Figure 4. Low Frequency Signal Input part. Table 5. Minimum External Resistor Values vs Supply Voltage on the IF input frequency and the LO frequency. Smaller V (V) R1, R7 (W ) C13 values have reduced impact on the LO output sup- CC 5 110 pression; larger values will degrade the conversion gain. 4.5 82.5 A single-ended 50W source can also be matched to the 4 54.9 differential signal inputs of the LT5521 without an input 3.5 38.3 transformer. Figure 5 shows an example topology for a 3.3 23.2 discrete balun, and Table 4 lists component values for Excessive mismatch between the external resistors R1 several frequencies. The discrete input match is intrinsi- and R7 will degrade performance, particularly LO sup- cally narrowband. LO suppression to the output is de- pression. Resistors with 1% mismatch are recommended graded and noise figure degrades by 4dB for input for optimum performance. frequencies greater than 200MHz. Noise figure degrada- tion is worse at lower input frequencies. Figure 2 shows RF chokes in series with R1 and R7. These inductors are optional. In general, the chokes improve the conversion gain and noise figure by 2dB at 3.3V (i.e., at the R1 minimum values of R1 and R7). The DC resistance varia- C16 110Ω LT5521 L4 tion of the RF chokes must be considered in the 1% source C2 82pF 2 IN+ resistance mismatch suggested for maintaining LO sup- 5I0FΩIN C14 C13 IN– pression performance. 3 Figure 6 indicates the typical performance of the LT5521 L3 110RΩ7 as the external source resistance (R1, R7) is varied while 5521 F05 keeping the supply current constant. Figure 6 data was 1nF taken without the benefit of input chokes, and shows the gradual gain degradation for smaller values of the input resistors R1 and R7. Figure 7 shows the typical behavior Figure 5. Alternative Transformerless Input Circuit Using Low Cost Discrete Components when the supply voltage is fixed and the core current is varied by adjusting values of the external resistors R1 and Table 4. Component Values for Discrete Bridge Balun Signal R7. Decreasing the core current decreases the power Input Matching consumption and improves noise figure but degrades IF (MHz) C14, C16 (pF) L3, L4 (nH) distortion performance. Figure␣8 demonstrates the im- 220 22 22 pact of the RF chokes in series with the source resistance 250 18 18 at 3.3V. There is a 2dB improvement in conversion gain 640 4.7 4.7 and noise figure and a corresponding decrease in IIP3. 5521f 11

LT5521 APPLICATIOU S IU FORW ATIOU 3.5 30 The user can tailor the biasing of the LT5521 to meet individual system requirements. It is recommended to 2.5 IIP3 25 IIP GAIN (dB) 1.5 ffTfILRAFOF = = == 2 2 1155..09°7CM5GGHHHzzz 20 3 (dBm) AND cmhiozeo ssee nas sitoivuirtcye t or epsoiswtaenr cseu pasp llya rvgaer iaatsi opno.ssible to mini- ON 0.5 15 NO Output Interface SI NF IS R E ONVE–0.5 10 FIGU A DC connection to VCC must be provided on the PCB to the C–1.5 GC 5 RE (d output pins. These pins will draw approximately 20mA B) each from the power supply. On-chip, there is a nominal –2.5 0 300W differential resistance between the output pins. 0 20 40 60 80 100 120 140 Figure 9 shows a typical matching circuit using an external R1 AND R7 (Ω) balun to provide differential to single-ended conversion. 5521 F06 Figure 6. IIP3, GC and Noise Figure vs External Resistance, LO suppression and 2xLO suppression are influenced by Constant Core Current (Variable Supply Voltage) the symmetry of the external output matching circuitry. PCB design must maintain the trace layout symmetry of 1.8 30 TA = 25°C the output pins as much as possible to minimize these GAIN (dB) 10..26 VfffILRFCOF C= == =2 11 54..097VM5GGHHHzzz IIP3 2250 IIP3 (dBm) AND sTuihrgeen␣ 9aM)ls i/.sA s-CuOitaMb leE TfoCr1 a.p6p-4li-c2a-t3io n4s:1 w tirthan osuftoprumt efrre q(Tu2e,n cFiiegs- ON 0 15 NO between 500MHz and 2700MHz. Output matching at vari- SI IS CONVER–0.6 NF 10 E FIGURE owuitsh f trheeq uoeuntpcuiets ( Lis1 a, cLh2i)e vaendd bDyC a bdldoicnkgin ingd cuacptaocrist oinr Cse3r,i aess –1.2 GC 5 (dB shown in Figure 9. Table 6 specifies center frequency and ) bandwidth of the output match for different matching –1.8 0 15 20 25 30 35 40 45 configurations. Figure 10 shows the typical output return CORE CURRENT (mA) loss vs frequency for 1GHz and 2GHz applications. Capaci- 5521 F07 tor C12 provides a solid AC ground at the RF output Figure 7. IIP3, G and Noise Figure vs Core Current, C frequency. Constant Supply Voltage 9 30 IIP3 7 25 IIP LT5521 3 AIN (dB) 5 TffILAFO == = 22 155.0°7CMGHHzz fVRCFC = = 1 3.9.35VGHz RFC NF 20 (dBm) AN OUT+ 12 L1 4T:21 C3 ON G 3 15 D NO OUT CONVERSI 1 GC RRFFCC 10 ISE FIGURE 300Ω VCC VCC –1 5 (d B) OUT– L2 C12 9 –3 0 5521 F09 25 30 35 40 45 50 55 CORE CURRENT (mA) 5521 F08 Figure 8. Comparison of 3.3V Performance With Figure 9. Simplified Output Circuit and Without Input RF Choke with External Matching Components 5521f 12

LT5521 APPLICATIOU S IU FORW ATIOU Table 6. Matching Values Using M/A-COM ETC1.6-4-2-3 Johanson Technology supplies the 3700BL15B100S hy- Output Transformer brid balun for use between 3.4GHz and 4GHz. With addi- fOUT L1, L2 C3 C12 D f (10dB RL) tional matching, this transformer can be used for 2.4GHz 0nH 82pF 82pF 450MHz applications between 3.3GHz and 3.7GHz. Example LT5521 2.2GHz 1nH 82pF 82pF 430MHz performance is shown in Figure 11. 2.0GHz 2.7nH 82pF 82pF 400MHz 1.7GHz 4.7nH 82pF 82pF 400MHz 10 22 1.3GHz 10nH 82pF 82pF 400MHz LS 8 20 IIP 1.0GHz 5 10nH 3.9pF 1nF 500MHz GAIN (dB) 64 TfIAF == 32050°CMHz HS IIP3 1186 3 (dBm) AND N HS NF N 0 1GHz RSIO 2 14 OISE LOSS (dB) –1–05 2GHz CONVE –02 GC LS LS 1120 FIGURE (dB) N R –15 HS U –4 8 ET 3.2 3.3 3.4 3.5 3.6 3.7 3.8 R –20 FREQUENCY (GHz) –25 5521 F11 Figure 11. LT5521 Performance for an Application Tuned to –30 3.5GHz with Low Side (LS) and High Side (HS) LO Injection 0.7 1.2 1.7 2.2 FREQUENCY (GHz) LO Interface 5521 F10 Figure 10. Output Return Loss vs Frequency The LO input pin is internally matched to 50W . It has an internal DC bias of 960mV. External AC coupling is re- For applications with LO and output frequencies below quired. Figure 12 shows a simplified schematic of the LO 1GHz, the M/A-COM MABAES0054 is recommended for input. Overdriving the LO input will dramatically reduce the output component T2. This transformer maintains the performance of the mixer. The LO input power should better low frequency output symmetry. Table 7 lists com- not exceed +1dBm for normal operation. Select C1 (Figure ponents necessary for a 750MHz output match using the 12) only large enough to achieve the desired LO input M/A-COM MABAES0054. return loss. This reduces external low frequency signal Table 7. Matching Values Using M/A-COM MABAES0054 amplification through the LO buffer. Output Transformer For applications with LO frequency in the range of 2.1GHz f L1, L2 C3 C12 D f (10dB RL) OUT to 2.4GHz, the LT5521 achieves improved distortion and 750MHz 33nH 82pF 1nF 500MHz Hybrid baluns provide a low cost alternative for differen- LT5521 tial to single-ended conversion. The critical performance parameters of conversion gain, IIP3, noise figure and LO VCC 60Ω suppression are largely unaffected by these transform- C1 ers. However, their limited bandwidth and reduced sym- 8Ω metry outside the frequency of operation degrades the L5O0ΩIN 15 suppression of higher order LO harmonics, particularly 60Ω 2xLO. Murata LBD21 series hybrid balun transformers, for example, can be used for output frequencies as low as 5521 F12 840MHz and as high as 2.4GHz. Figure 12. Simplified LO Input Circuit 5521f 13

LT5521 APPLICATIOU S IU FORW ATIOU 0 0W resistor. If the shutdown function is not required, then the EN pin should be wired directly to the V power supply –5 CC on the PCB. B) –10 SS (d –15 C1 = 6.8pF Supply Decoupling O L N UR –20 The power supply decoupling shown in the schematic of T C1 = 2.7pF E R –25 Figure 1 is recommended to minimize spurious signal coupling into the output through the power supply. –30 –35 ACPR Performance 0 500 1000150020002500300035004000 FREQUENCY (MHz) Because of its high linearity and low noise, the LT5521 offers 5521 F13 Figure 13. LO Port Return Loss outstanding ACPR performance in a variety of applications. For example, Figures 15 and 16 show ACPR and Alternate noise performance with slightly reduced current through Channel measurements for single channel and 4-channel the mixer core. Accordingly, in a 5V application operating 64 DPCH W-CDMA signals at 1.95GHz output frequency. within this LO frequency range, the recommended source resistor value (R1 and R7) is increased to 121W . –30 –130 TA = 25°C fRF = 1.95GHz –40 fIF = 70MHz –135 Enable Interface fLO = 1.88GHz N –50 –140 O Figure 14 shows a simplified schematic of the EN pin ISE interface. The voltage necessary to turn on the LT5521 is PR –60 –145 FLOO 2.9V. To disable the chip, the enable voltage must be below AC –70 –150 R (d ACPR Bm 0.2V. If the EN pin is not connected, the chip is disabled. –80 –155 /Hz) It is not recommended, however, that any pins be left –90 –160 floating for normal operation. 30MHz OFFSET NOISE –100 –165 –40 –30 –20 –10 0 10 It is important that the voltage at the EN pin never exceed OUTPUT CHANNEL POWER (dBm) V , the power supply voltage, by more than 0.2V. If this CC 5521 F15 should occur, the supply current could be sourced through Figure 15. Single Channel W-CDMA ACPR the EN pin ESD protection diodes, potentially damaging and 30MHz Offset Noise Performance the IC. The resistor R8 (Figure 1) in series with the EN pin on the demo board is populated with a 10kW resistor to –50 –135 protect the EN pin to avoid inadvertant damage to the IC. –55 –140 For timing measuremLT5e5n21ts, this resistor is replaced with a CPR AND AltCPR (dB) –––766050 TffRIAFF = == 7 2105.M9°C5HGzHz AltCPR ACPR –––111554505NOISE FLOOR (dBm/H A fLO = 1.88GHz z) –75 –160 VCC 30MHz OFFSET NOISE –80 –165 –40 –35 –30 –25 –20 –15 OUTPUT CHANNEL POWER, EACH CHANNEL (dBm) EN 1635 G24 5 Figure 16. 4-Channel W-CDMA ACPR, 5521 F14 AltCPR and 30MHz Offset Noise Floor Figure 14. Enable Input Circuit 5521f 14

LT5521 APPLICATIOU S IU FORW ATIOU Figure 17. Top View of Demo Board PACKAGE DESCRIPTIOU UF Package 16-Lead Plastic QFN (4mm · 4mm) (Reference LTC DWG # 05-08-1692) BOTTOM VIEW—EXPOSED PAD 4.00 – 0.10 0.75 – 0.05 R = 0.115 0.55 – 0.20 (4 SIDES) TYP 15 16 0.72 – 0.05 PIN 1 TOP MARK (NOTE 6) 1 2 4.35 – 0.05 2.15 – 0.05 2.15 – 0.10 (4 SIDES) (4-SIDES) 2.90 – 0.05 PACKAGE OUTLINE (UF) QFN 1103 0.30 – 0.05 0.200 REF 0.30 – 0.05 0.65 BSC 0.00 – 0.05 0.65 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS NOTE: 1. DRAWING CONFORMS TO JEDEC PACKAGE OUTLINE MO-220 VARIATION (WGGC) 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 0.15mm 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 5521f Information furnished by Linear Technology Corporation is believed to be accurate and reliable. 15 However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

LT5521 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS Infrastructure LT5511 High Linearity Upconverting Mixer RF Output to 3GHz, 17dBm IIP3, Integrated LO Buffer LT5512 DC-3GHz High Signal Level Downconverting Mixer DC to 3GHz, 21dBm IIP3, Integrated LO Buffer LT5514 Ultralow Distortion, Wideband Digitally Controlled BW = 850MHz, OIP3 = 47dBm at 100MHz, 22.5dB Gain Control Range Gain Amplifier/ADC Driver LT5515 1.5GHz to 2.5GHz Direct Conversion Quadrature Demodulator 20dBm IIP3, Integrated LO Quadrature Generator LT5516 0.8GHz to 1.5GHz Direct Conversion Quadrature Demodulator 21.5dBm IIP3, Integrated LO Quadrature Generator LT5517 40MHz to 900MHz Quadrature Demodulator 21dBm IIP3, Integrated LO Quadrature Generator LT5519 0.7GHz to 1.4GHz High Linearity Upconverting Mixer 17.1dBm IIP3 at 1GHz, Integrated RF Output Transformer with 50W Matching, Single-Ended LO and RF Ports Operation LT5520 1.3GHz to 2.3GHz High Linearity Upconverting Mixer 15.9dBm IIP3 at 1.9GHz, Integrated RF Output Transformer with 50W Matching, Single-Ended LO and RF Ports Operation LT5522 600MHz to 2.7GHz High Signal Level Downconverting Mixer 4.5V to 5.25V Supply, 25dBm IIP3 at 900MHz, NF = 12.5dB, 50W Single-Ended RF and LO Ports RF Power Detectors LT5504 800MHz to 2.7GHz RF Measuring Receiver 80dB Dynamic Range, Temperature Compensated, 2.7V to 5.25V Supply LTC®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 Linear Dynamic Range, Low Power Consumption, SC70 Package LTC5530 300MHz to 7GHz Precision RF Power Detector Precision V Offset Control, Shutdown, Adjustable Gain OUT LTC5531 300MHz to 7GHz Precision RF Power Detector Precision V Offset Control, Shutdown, Adjustable Offset OUT LTC5532 300MHz to 7GHz Precision RF Power Detector Precision V Offset Control, Adjustable Gain and Offset OUT LT5534 50MHz to 3GHz RF Power Detector 60dB Dynamic Range, Temperature Compensated, SC70 Package Low Voltage RF Building Blocks 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 1.8V to 5.25V Supply, Four-Step RF Power Control, Upconverting Mixer 120MHz Modulation Bandwidth LT5506 500MHz Quadrature IF Demodulator with VGA 1.8V to 5.25V Supply, 40MHz to 500MHz IF, –4dB to 57dB Linear Power Gain, 8.8MHz Baseband Bandwidth LT5546 500MHz Ouadrature IF Demodulator with 17MHz Baseband Bandwidth, 40MHz to 500MHz IF, 1.8V to 5.25V VGA and 17MHz Baseband Bandwidth Supply, –7dB to 56dB Linear Power Gain RF Power Controllers LTC1757A RF Power Controller Multiband GSM/DCS/GPRS Mobile Phones LTC1758 RF Power Controller Multiband GSM/DCS/GPRS Mobile Phones LTC1957 RF Power Controller Multiband GSM/DCS/GPRS Mobile Phones LTC4400 SOT-23 RF PA Controller Multiband GSM/DCS/GPRS Phones, 45dB Dynamic Range, 450kHz Loop BW LTC4401 SOT-23 RF PA Controller Multiband GSM/DCS/GPRS Phones, 45dB Dynamic Range, 250kHz Loop BW LTC4403 RF Power Controller for EDGE/TDMA Multiband GSM/GPRS/EDGE Mobile Phones 5521f 16 Linear Technology Corporation LT/TP 0604 1K • PRINTED IN THE USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 l FAX: (408) 434-0507 l www.linear.com ª LINEAR TECHNOLOGY CORPORATION 2004

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