LT5527 400MHz to 3.7GHz High Signal Level Downconverting Mixer U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO 50Ω Single-Ended RF and LO Ports Wide RF Frequency Range: 400MHz to 3.7GHz* High Input IP3: 24.5dBm at 900MHz 23.5dBm at 1900MHz Conversion Gain: 3.2dB at 900MHz 2.3dB at 1900MHz Integrated LO Buffer: Low LO Drive Level High LO-RF and LO-IF Isolation Low Noise Figure: 11.6dB at 900MHz 12.5dB at 1900MHz Very Few External Components Enable Function 4.5V to 5.25V Supply Voltage Range 16-Lead (4mm × 4mm) QFN Package U APPLICATIO S ■ ■ ■ ■ The RF input is internally matched to 50Ω from 1.7GHz to 3GHz, and the LO input is internally matched to 50Ω from 1.2GHz to 5GHz. The frequency range of both ports is easily extended with simple external matching. The IF output is partially matched and usable for IF frequencies up to 600MHz. The LT5527’s high level of integration minimizes the total solution cost, board space and system-level variation. Cellular, WCDMA, TD-SCDMA and UMTS Infrastructure GSM900/GSM1800/GSM1900 Infrastructure 900MHz/2.4GHz/3.5GHz WLAN MMDS, WiMAX High Linearity Downmixer Applications , LTC and LT are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. *Operation over a wider frequency range is possible with reduced performance. Consult factory for information and assistance. U ■ The LT®5527 active mixer is optimized for high linearity, wide dynamic range downconverter applications. The IC includes a high speed differential LO buffer amplifier driving a double-balanced mixer. Broadband, integrated transformers on the RF and LO inputs provide singleended 50Ω interfaces. The differential IF output allows convenient interfacing to differential IF filters and amplifiers, or is easily matched to drive 50Ω single-ended, with or without an external transformer. TYPICAL APPLICATIO High Signal Level Downmixer for Multi-Carrier Wireless Infrastructure LO INPUT –3dBm (TYP) 1.9GHz Conversion Gain, IIP3, SSB NF and LO-RF Leakage vs LO Power 100nH IF+ 1nF 220nH RF INPUT RF IF BIAS GND EN VCC2 VCC1 4.7pF – 100nH 5V 1nF 1µF IF OUTPUT 240MHz –20 –25 –30 IF = 240MHz LOW SIDE LO –35 TA = 25°C –40 VCC = 5V –45 20 18 16 14 –50 12 SSB NF 10 –55 8 –60 LO-RF 6 –65 4 G C 2 –9 –70 LO-RF LEAKAGE (dBm) 4.7pF GC, SSB NF (dB), IIP3 (dBm) LT5527 24 22 IIP3 –75 –7 –5 –3 –1 LO POWER (dBm) 1 3 5527 TA01b 5527 TA01a 5527f 1 LT5527 W W W AXI U U U W PACKAGE/ORDER I FOR ATIO U ABSOLUTE RATI GS (Note 1) ORDER PART NUMBER NC NC LO NC TOP VIEW 16 15 14 13 NC 1 12 GND NC 2 RF 3 LT5527EUF 11 IF+ 17 10 IF– 9 GND NC 4 7 8 UF PART MARKING NC 6 VCC1 EN 5 VCC2 Supply Voltage (VCC1, VCC2, IF+, IF–) ...................... 5.5V Enable Voltage ............................... –0.3V to VCC + 0.3V LO Input Power (380MHz to 4GHz) .................. +10dBm LO Input DC Voltage ............................ –1V to VCC + 1V RF Input Power (400MHz to 4GHz) .................. +12dBm RF Input DC Voltage ............................................ ±0.1V Operating Temperature Range ............... – 40°C to 85°C Storage Temperature Range ................ – 65°C to 125°C Junction Temperature (TJ)................................... 125°C UF PACKAGE 16-LEAD (4mm × 4mm) PLASTIC QFN 5527 TJMAX = 125°C, θJA = 37°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 VCC = 5V, EN = High, TA = 25°C, unless otherwise specified. Test circuit shown in Figure 1. (Note 3) PARAMETER CONDITIONS MIN TYP MAX UNITS 5 5.25 V DC Power Supply Requirements (VCC) Supply Voltage Supply Current 4.5 VCC1 (Pin 7) VCC2 (Pin 6) IF+ + IF– (Pin 11 + Pin 10) Total Supply Current 23.2 2.8 52 78 60 88 mA mA mA mA Enable (EN) Low = Off, High = On Shutdown Current EN = Low 100 Input High Voltage (On) 3 Input Low Voltage (Off) EN Pin Input Current µA V DC EN = 5V DC 50 0.3 V DC 90 µA Turn-ON Time 3 µs Turn-OFF Time 3 µs AC ELECTRICAL CHARACTERISTICS Test circuit shown in Figure 1. (Notes 2, 3) PARAMETER CONDITIONS RF Input Frequency Range No External Matching (Midband) With External Matching (Low Band or High Band) 400 No External Matching With External Matching 380 LO Input Frequency Range MIN TYP MAX UNITS 3700 MHz MHz 1700 to 3000 1200 to 3500 MHz MHz MHz IF Output Frequency Range Requires Appropriate IF Matching 0.1 to 600 RF Input Return Loss ZO = 50Ω, 1700MHz to 3000MHz >10 dB LO Input Return Loss ZO = 50Ω, 1200MHz to 3400MHz >12 dB IF Output Impedance Differential at 240MHz LO Input Power 1200MHz to 3500MHz 380MHz to 1200MHz 407Ω||2.5pF –8 –5 –3 0 R||C 2 5 dBm dBm 5527f 2 LT5527 AC ELECTRICAL CHARACTERISTICS Standard Downmixer Application: VCC = 5V, EN = High, TA = 25°C, PRF = – 5dBm (–5dBm/tone for 2-tone IIP3 tests, ∆f = 1MHz), fLO = fRF – fIF, PLO = –3dBm (0dBm for 450MHz and 900MHz tests), IF output measured at 240MHz, unless otherwise noted. Test circuit shown in Figure 1. (Notes 2, 3, 4) PARAMETER CONDITIONS Conversion Gain RF = 450MHz, IF = 140MHz, High Side LO RF = 900MHz, IF = 140MHz RF = 1700MHz RF = 1900MHz RF = 2200MHz RF = 2650MHz RF = 3500MHz, IF = 380MHz MIN Conversion Gain vs Temperature TA = – 40°C to 85°C, RF = 1900MHz Input 3rd Order Intercept TYP MAX UNITS 2.5 3.4 2.3 2.3 2.0 1.8 0.3 dB dB dB dB dB dB dB –0.018 dB/°C RF = 450MHz, IF = 140MHz, High Side LO RF = 900MHz, IF = 140MHz RF = 1700MHz RF = 1900MHz RF = 2200MHz RF = 2650MHz RF = 3500MHz, IF = 380MHz 23.2 24.5 24.2 23.5 22.7 20.8 18.2 dBm dBm dBm dBm dBm dBm dBm Single-Sideband Noise Figure RF = 450MHz, IF = 140MHz, High Side LO RF = 900MHz, IF = 140MHz RF = 1700MHz RF = 1900MHz RF = 2200MHz RF = 2650MHz RF = 3500MHz, IF = 380MHz 13.3 11.6 12.1 12.5 13.2 13.9 16.1 dB dB dB dB dB dB dB LO to RF Leakage fLO = 400MHz to 2100MHz fLO = 2100MHz to 3200MHz ≤–44 ≤–36 dBm dBm LO to IF Leakage fLO = 400MHz to 700MHz fLO = 700MHz to 3200MHz ≤–40 ≤–50 dBm dBm RF to LO Isolation fRF = 400MHz to 2200MHz fRF = 2200MHz to 3700MHz >43 >38 dB dB RF to IF Isolation fRF = 400MHz to 800MHz fRF = 800MHz to 3700MHz >42 >54 dB dB 2RF-2LO Output Spurious Product (fRF = fLO + fIF/2) 900MHz: fRF = 830MHz at –5dBm, fIF = 140MHz 1900MHz: fRF = 1780MHz at –5dBm, fIF = 240MHz –60 –65 dBc dBc 3RF-3LO Output Spurious Product (fRF = fLO + fIF/3) 900MHz: fRF = 806.67MHz at –5dBm, fIF = 140MHz 1900MHz: fRF = 1740MHz at –5dBm, fIF = 240MHz –73 –63 dBc dBc Input 1dB Compression RF = 450MHz, IF = 140MHz, High Side LO RF = 900MHz, IF = 140MHz RF = 1900MHz 9.5 8.9 9.0 dBm dBm dBm Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: 450MHz, 900MHz and 3500MHz performance measured with external LO and RF matching. See Figure 1 and Applications Information. 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: SSB Noise Figure measurements performed with a small-signal noise source and bandpass filter on RF input, and no other RF signal applied. 5527f 3 LT5527 U W TYPICAL AC PERFOR A CE CHARACTERISTICS Midband (No external RF/LO matching) VCC = 5V, EN = High, PRF = –5dBm (–5dBm/tone for 2-tone IIP3 tests, ∆f = 1MHz), PLO = –3dBm, IF output measured at 240MHz, unless otherwise noted. Test circuit shown in Figure 1. Conversion Gain, IIP3 and NF vs RF Frequency LO Leakage vs LO Frequency IIP3 –35 20 –40 18 –45 SSB NF 14 12 TA = 25°C IF = 240MHz LOW SIDE LO HIGH SIDE LO 10 8 6 4 GC 2 0 1700 1900 2300 2500 2100 RF FREQUENCY (MHz) TA = 25°C PLO = –3dBm –40 –45 LO-RF –50 –55 –60 LO-IF –65 –70 –85 –85 1800 2100 2400 2700 LO FREQUENCY (MHz) 23 8 23 8 22 7 22 7 4 18 GC –25 25 50 0 TEMPERATURE (°C) IF = 240MHz 1700MHz 1900MHz 2200MHz 19 3 18 2 17 15 –50 –25 25 50 0 TEMPERATURE (°C) 22 15 13 SSB NF LOW SIDE LO IF = 240MHz –40°C 25°C 85°C GC, SSB NF (dB), IIP3 (dBm) GC, SSB NF (dB), IIP3 (dBm) 24 23 17 11 9 7 5 3 1 20 –5 –3 –1 LO INPUT POWER (dBm) 1 8 6 GC 0 4.5 5 4.75 5.25 SUPPLY VOLTAGE (V) 5.5 5527 G06 16 14 2200MHz Conversion Gain, IIP3 and NF vs LO Power IIP3 SSB NF 22 LOW SIDE LO IF = 240MHz –40°C 25°C 85°C 12 10 8 6 GC 3 5527 G07 0 20 IIP3 18 16 14 SSB NF 12 LOW SIDE LO IF = 240MHz –40°C 25°C 85°C 10 8 6 4 GC 2 2 –7 SSB NF 24 18 4 GC –9 12 10 2 0 100 75 14 4 1 LOW SIDE LO IF = 240MHz –40°C 25°C 85°C 18 16 1900MHz Conversion Gain, IIP3 and NF vs LO Power 25 19 2 IIP3 20 5527 G05 1700MHz Conversion Gain, IIP3 and NF vs LO Power IIP3 4 GC 5527 G04 21 5 3 16 1 0 100 75 6 21 20 24 22 GC, SSB NF (dB), IIP3 (dBm) 16 IIP3 GC (dB) 5 IIP3 (dBm) 9 GC (dB) IIP3 (dBm) 10 24 6 2700 1900MHz Conversion Gain, IIP3 and NF vs Supply Voltage 9 IF = 240MHz 1700MHz 1900MHz 2200MHz 2300 2500 2100 RF FREQUENCY (MHz) 5527 G03 24 21 1900 5527 G02 25 15 –50 –90 1700 3000 10 17 RF-IF Conversion Gain and IIP3 vs Temperature (High Side LO) IIP3 19 –65 –70 –75 Conversion Gain and IIP3 vs Temperature (Low Side LO) 20 –60 –80 1500 RF-LO –55 –75 5527 G01 25 –50 –80 –90 1200 2700 TA = 25°C –35 GC, SSB NF (dB), IIP3 (dBm) 16 LO LEAKAGE (dBm) GC, SSB NF (dB), IIP3 (dBm) 22 RF Isolation vs RF Frequency –30 ISOLATION (dB) –30 24 0 –9 –7 –5 –3 –1 LO INPUT POWER (dBm) 1 3 5527 G08 –9 –7 –5 –3 –1 LO INPUT POWER (dBm) 1 3 5527 G09 5527f 4 LT5527 U W TYPICAL AC PERFOR A CE CHARACTERISTICS Midband (No external RF/LO matching) VCC = 5V, EN = High, PRF = –5dBm (–5dBm/tone for 2-tone IIP3 tests, ∆f = 1MHz), PLO = –3dBm, IF output measured at 240MHz, unless otherwise noted. Test circuit shown in Figure 1. IF Output Power, IM3 and IM5 vs RF Input Power (2 Input Tones) IFOUT, 2 × 2 and 3 × 3 Spurs vs RF Input Power (Single Tone) 10 15 IFOUT –10 –20 –40 –50 TA = 25°C RF1 = 1899.5MHz RF2 = 1900.5MHz LO = 1660MHz –60 –70 –15 –90 –100 –21 –55 IFOUT (RF = 1900MHz) –25 –35 –45 3RF-3LO (RF = 1740MHz) –55 –65 IM3 –80 –50 RELATIVE SPUR LEVEL (dBc) TA = 25°C 5 LO = 1660MHz –5 IF = 240MHz OUTPUT POWER (dBm) OUTPUT POWER/TONE (dBm) 0 –30 2 × 2 and 3 × 3 Spurs vs LO Power (Single Tone) 2RF-2LO (RF = 1780MHz) –75 2RF-2LO (RF = 1780MHz) –70 –75 –80 –85 TA = 25°C LO = 1660MHz IF = 240MHz PRF = –5dBm –90 –100 –95 –18 –15 –12 –9 –6 –3 0 3 6 RF INPUT POWER (dBm) 0 –6 –3 –18 –15 –12 –9 RF INPUT POWER (dBm/TONE) 5527 G10 –65 –95 –85 IM5 3RF-3LO (RF = 1740MHz) –60 9 –9 12 5527 G11 –7 –3 –1 –5 LO INPUT POWER (dBm) 3 1 5527 G12 High Band (3500MHz application with external RF matching) VCC = 5V, EN = High, PRF = –5dBm (–5dBm/tone for 2-tone IIP3 tests, ∆f = 1MHz), low side LO, PLO = –3dBm, IF output measured at 380MHz, unless otherwise noted. Test circuit shown in Figure 1. Conversion Gain, IIP3 and SSB NF vs RF Frequency 3500MHz Conversion Gain, IIP3 and SSB NF vs LO Power 20 14 12 LOW SIDE LO IF = 380MHz TA = 25°C 10 8 6 4 3500 3400 3600 RF FREQUENCY (MHz) 3700 SSB NF –30 15 13 11 LOW SIDE LO IF = 380MHz TA = 25°C 9 7 5 –40 –7 5527 G13 –3 –1 –5 LO INPUT POWER (dBm) 3 1 30 20 LO-IF –70 3000 –1 40 RF-LO –50 GC –9 50 LO-RF –60 3 1 GC 0 3300 60 IIP3 LO LEAKAGE (dBm) SSB NF GC, SSB NF (dB), IIP3 (dBm) 17 16 2 –20 19 IIP3 RF-LO ISOLATION (dB) GC, SSB NF (dB), IIP3 (dBm) 18 LO Leakage and RF-LO Isolation vs LO and RF Frequency 3400 3200 3600 LO/RF FREQUENCY (MHz) 5527 G14 10 3800 5527 G15 Low Band (450MHz application with external RF/LO matching) VCC = 5V, EN = High, PRF = –5dBm (–5dBm/tone for 2-tone IIP3 tests, ∆f = 1MHz), PLO = 0dBm, IF output measured at 140MHz, unless otherwise noted. Test circuit shown in Figure 1. Conversion Gain, IIP3 and NF vs RF Frequency 14 IIP3 22 HIGH SIDE LO TA = 25°C IF = 140MHz SSB NF 12 10 8 6 20 16 14 8 6 2 0 5527 G18 GC –6 TA = 25°C PLO = 0dBm –30 10 4 500 SSB NF HIGH SIDE LO IF = 140MHz –40°C 25°C 85°C 12 2 450 425 475 RF FREQUENCY (MHz) IIP3 18 4 GC 0 400 –20 LO LEAKAGE (dBm) 20 18 16 LO Leakage vs LO Frequency 24 GC, SSB NF (dB), IIP3 (dBm) GC, SSB NF (dB), IIP3 (dBm) 24 22 450MHz Conversion Gain, IIP3 and NF vs LO Power LO-IF (450MHz APP) –40 LO-RF (900MHz APP) –50 LO-RF (450MHz APP) –60 LO-IF (900MHz APP) –70 –4 –2 0 2 LO INPUT POWER (dBm) 4 6 5527 G19 –80 400 600 800 1000 LO FREQUENCY (MHz) 1200 5527 G20 5527f 5 LT5527 U W TYPICAL AC PERFOR A CE CHARACTERISTICS Low Band (900MHz application with external RF/LO matching) VCC = 5V, EN = High, PRF = –5dBm (–5dBm/tone for 2-tone IIP3 tests, ∆f = 1MHz), PLO = 0dBm, IF output measured at 140MHz, unless otherwise noted. Test circuit shown in Figure 1. Conversion Gain, IIP3 and NF vs RF Frequency (900MHz Low Side Application) 25 23 LOW SIDE LO TA = 25°C IF = 140MHz 19 17 15 13 9 SSB NF 7 5 3 17 15 SSB NF 13 11 9 7 800 850 900 950 1000 1050 5527 G21 RF FREQUENCY (MHz) 23 21 HIGH SIDE LO TA = 25°C IF = 140MHz 19 17 15 13 SSB NF 7 3 GC, SSB NF (dB), IIP3 (dBm) GC, SSB NF (dB), IIP3 (dBm) 25 23 IIP3 5 –70 –6 –4 –2 0 2 LO INPUT POWER (dBm) 4 6 5527 G22 –100 –18 –15 –12 –9 –6 –3 0 3 6 RF INPUT POWER (dBm) –45 IIP3 HIGH SIDE LO IF = 140MHz –40°C 25°C 85°C 19 17 15 13 SSB NF 11 9 7 GC 9 12 5527 G23 2 × 2 and 3 × 3 Spurs vs LO Power (Single Tone) –40 21 1 850 900 950 1000 1050 RF FREQUENCY (MHz) 5527 G24 3RF-3LO (RF = 806.67MHz) –80 –50 TA = 25°C LO = 760MHz IF = 140MHz PRF = –5dBm –55 2RF-2LO (RF = 830MHz) –60 –65 –70 –75 3RF-3LO (RF = 806.67MHz) –80 –85 3 800 2RF-2LO (RF = 830MHz) –60 –90 5 GC 1 750 –40 –50 900MHz Conversion Gain, IIP3 and NF vs LO Power (High Side LO) 25 9 –20 –30 3 1 IFOUT (RF = 900MHz) –10 GC Conversion Gain, IIP3 and NF vs RF Frequency (900MHz High Side Application) 11 LOW SIDE LO IF = 140MHz –40°C 25°C 85°C 19 5 GC 1 750 IIP3 21 20 TA = 25°C 10 LO = 760MHz 0 IF = 140MHz OUTPUT POWER (dBm) IIP3 21 11 IFOUT, 2 × 2 and 3 × 3 Spurs vs RF Input Power (Single Tone) RELATIVE SPUR LEVEL (dBc) GC, SSB NF (dB), IIP3 (dBm) 23 GC, SSB NF (dB), IIP3 (dBm) 25 900MHz Conversion Gain, IIP3 and NF vs LO Power (Low Side LO) –90 –6 –4 –2 0 2 LO INPUT POWER (dBm) 4 6 U W TYPICAL DC PERFOR A CE CHARACTERISTICS Supply Current vs Supply Voltage –6 5527 G25 –4 0 2 –2 LO INPUT POWER (dBm) 4 6 5527 G26 Test circuit shown in Figure 1. Shutdown Current vs Supply Voltage 100 82 81 SHUTDOWN CURRENT (µA) SUPPLY CURRENT (mA) 80 85°C 79 60°C 78 25°C 76 0°C –40°C 75 74 73 10 85°C 1 72 71 60°C 25°C –40°C 0°C 0.1 4.5 5 4.75 5.25 SUPPLY VOLTAGE (V) 5.5 5527 G16 4.5 4.75 5 5.25 SUPPLY VOLTAGE (V) 5.5 5527 G17 5527f 6 LT5527 U U U PI FU CTIO S NC (Pins 1, 2, 4, 8, 13, 14, 16): Not Connected Internally. These pins should be grounded on the circuit board for improved LO-to-RF and LO-to-IF isolation. be externally connected to the VCC2 pin and decoupled with 1000pF and 1µF capacitors. GND (Pins 9, 12): Ground. These pins are internally connected to the backside ground for improved isolation. They should be connected to the RF ground on the circuit board, although they are not intended to replace the primary grounding through the backside contact of the package. RF (Pin 3): 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. If the RF source is not DC blocked, then a series blocking capacitor must be used. The RF input is internally matched from 1.7GHz to 3GHz. Operation down to 400MHz or up to 3700MHz is possible with simple external matching. IF–, IF + (Pins 10, 11): Differential Outputs for the IF Signal. An impedance transformation may be required to match the outputs. These pins must be connected to VCC through impedance matching inductors, RF chokes or a transformer center tap. EN (Pin 5): Enable Pin. When the input enable voltage is higher than 3V, the mixer circuits supplied through Pins 6, 7, 10 and 11 are enabled. When the input voltage is less than 0.3V, all circuits are disabled. Typical input current is 50µA for EN = 5V and 0µA when EN = 0V. The EN pin should not be left floating. Under no conditions should the EN pin voltage exceed VCC + 0.3V, even at start-up. LO (Pin 15): Single-Ended Input for the Local Oscillator Signal. This pin is internally connected to the primary side of the LO transformer, which is internally DC blocked. An external blocking capacitor is not required. The LO input is internally matched from 1.2GHz to 5GHz. Operation down to 380MHz is possible with simple external matching. VCC2 (Pin 6): Power Supply Pin for the Bias Circuits. Typical current consumption is 2.8mA. This pin should be externally connected to the VCC1 pin and decoupled with 1000pF and 1µF capacitors. Exposed Pad (Pin 17): Circuit Ground Return for the Entire IC. This must be soldered to the printed circuit board ground plane. VCC1 (Pin 7): Power Supply Pin for the LO Buffer Circuits. Typical current consumption is 23.2mA. This pin should W BLOCK DIAGRA 15 LO REGULATOR LIMITING AMPLIFIERS VCC1 GND 12 LINEAR AMPLIFIER 3 EXPOSED 17 PAD IF+ IF– RF DOUBLE-BALANCED MIXER 11 10 GND 9 BIAS EN 5 VCC1 VCC2 6 7 5525 BD 5527f 7 LT5527 TEST CIRCUITS LOIN L4 C4 0.062" 16 EXTERNAL MATCHING FOR LOW FREQUENCY LO ONLY 1 2 RFIN RF GND εR = 4.4 0.018" ZO 50Ω NC 15 LO 14 NC BIAS 13 0.018" NC NC GND NC IF 4 L (mm) C5 3 RF GND NC • 1 9 4 5 L2 IFOUT 240MHz VCC2 VCC1 NC 5 EN • 2 C3 10 IF – EN EXTERNAL MATCHING FOR LOW BAND OR HIGH BAND ONLY T1 L1 + 11 LT5527 3 GND 12 6 7 8 VCC APPLICATION RF LO LO MATCH C1 RF MATCH GND L4 C4 L C5 450MHz High Side 6.8nH 10pF 4.5mm 12pF 900MHz Low Side C2 5527 F01 3.9nH 5.6pF 1.3mm 3.9pF 900MHz High Side — 2.7pF 1.3mm 3.9pF 3500MHz Low Side — — 4.5mm 0.5pF REF DES VALUE SIZE PART NUMBER REF DES C1 1000pF 0402 AVX 04025C102JAT L4, C4, C5 C2 1µF 0603 AVX 0603ZD105KAT L1, L2 C3 2.7pF 0402 AVX 04025A2R7CAT T1 VALUE 82nH SIZE PART NUMBER 0402 See Applications Information 0603 Toko LLQ1608-A82N 4:1 M/A-Com ETC4-1-2 (2MHz to 800MHz) Figure 1. Downmixer Test Schematic—Standard IF Matching (240MHz IF) LOIN L4 DISCRETE IF BALUN C4 16 EXTERNAL MATCHING FOR LOW FREQUENCY LO ONLY RFIN 1 2 ZO 50Ω L (mm) C5 EXTERNAL MATCHING FOR LOW BAND OR HIGH BAND ONLY NC 15 LO 14 NC 13 NC NC GND IF NC 12 C6 + 11 L1 L3 LT5527 3 4 RF IF – NC GND EN EN 5 C7 10 7 IFOUT 240MHz 9 L2 VCC2 VCC1 NC 6 C3 8 VCC C1 C2 GND 5527 F02 REF DES VALUE SIZE PART NUMBER REF DES C1, C3 1000pF 0402 AVX 04025C102JAT L4, C4, C5 C2 C6, C7 VALUE SIZE PART NUMBER 0402 See Applications Information 1µF 0603 AVX 0603ZD105KAT L1, L2 100nH 0603 Toko LLQ1608-AR10 4.7pF 0402 AVX 04025A4R7CAT L3 220nH 0603 Toko LLQ1608-AR22 Figure 2. Downmixer Test Schematic—Discrete IF Balun Matching (240MHz IF) 5527f 8 LT5527 U W U U APPLICATIO S I FOR ATIO The LT5527 consists of a high linearity double-balanced mixer, RF buffer amplifier, high speed limiting LO buffer amplifier and bias/enable circuits. The RF and LO inputs are both single ended. The IF output is differential. Low side or high side LO injection can be used. Two evaluation circuits are available. The standard evaluation circuit, shown in Figure 1, incorporates transformerbased IF matching and is intended for applications that require the lowest LO-IF leakage levels and the widest IF bandwidth. The second evaluation circuit, shown in Figure 2, replaces the IF transformer with a discrete IF balun for reduced solution cost and size. The discrete IF balun delivers comparable noise figure and linearity, higher conversion gain, but degraded LO-IF leakage and reduced IF bandwidth. RF Input Port The mixer’s RF input, shown in Figure 3, consists of an integrated transformer and a high linearity differential amplifier. The primary terminals of the transformer are connected to the RF input pin (Pin 3) and ground. The secondary side of the transformer is internally connected to the amplifier’s differential inputs. at Pin 3, which improves the 1.7GHz return loss to greater than 20dB. Likewise, the 2.7GHz match can be improved to greater than 30dB with a series 1.5nH inductor. A series 1.5nH/2.7pF network will simultaneously optimize the lower and upper band edges and expand the RF input bandwidth to 1.1GHz-3.3GHz. Measured RF input return losses for these three cases are also plotted in Figure 4a. Alternatively, the input match can be shifted down, as low as 400MHz or up to 3700MHz, by adding a shunt capacitor (C5) to the RF input. A 450MHz input match is realized with C5 = 12pF, located 4.5mm away from Pin 3 on the evaluation board’s 50Ω input transmission line. A 900MHz input match requires C5 = 3.9pF, located at 1.3mm. A 3500MHz input match is realized with C5 = 0.5pF, located 0 RF PORT RETURN LOSS (dB) Introduction –15 –20 TO MIXER ZO = 50Ω L = L (mm) 3 RF SERIES 1.5nH –30 0.2 0.7 1.2 1.7 2.2 2.7 3.2 FREQUENCY (GHz) 3.7 4.2 5527 F04a (4a) Series Reactance Matching RF PORT RETURN LOSS (dB) 0 –5 –10 –15 NO EXTERNAL MATCHING –20 450MHz C5 = 12pF L = 4.5mm –30 0.2 0.7 900MHz C5 = 3.9pF L = 1.3mm 3.5GHz C5 = 0.5pF L = 4.5mm 1.2 1.7 2.2 2.7 3.2 RF FREQUENCY (GHz) 3.7 4.2 5527 F04b C5 5527 F03 Figure 3. RF Input Schematic SERIES 1.5nH SERIES 2.7pF SERIES 2.7pF –25 EXTERNAL MATCHING FOR LOW BAND OR HIGH BAND ONLY RFIN –10 –25 One terminal of the transformer’s primary is internally grounded. If the RF source has DC voltage present, then a coupling capacitor must be used in series with the RF input pin. The RF input is internally matched from 1.7GHz to 3GHz, requiring no external components over this frequency range. The input return loss, shown in Figure 4a, is typically 10dB at the band edges. The input match at the lower band edge can be optimized with a series 2.7pF capacitor NO EXTERNAL MATCHING –5 (4b) Series Shunt Matching Figure 4. RF Input Return Loss With and Without External Matching 5527f 9 LT5527 U W U U APPLICATIO S I FOR ATIO Input return loss for these three cases (450MHz, 900MHz and 3500MHz) are plotted in Figure 4b. The input return loss with no external matching is repeated in Figure 4b for comparison. RF input impedance and S11 versus frequency (with no external matching) is listed in Table 1 and referenced to Pin 3. The S11 data can be used with a microwave circuit simulator to design custom matching networks and simulate board-level interfacing to the RF input filter. Table 1. RF Input Impedance vs Frequency FREQUENCY (MHz) INPUT IMPEDANCE MAG S11 ANGLE 50 4.8 + j2.6 0.825 173.9 300 9.0 + j11.9 0.708 152.5 450 11.9 + j15.3 0.644 144.3 600 14.3 + j18.2 0.600 137.2 900 19.4 + j23.8 0.529 123.2 1200 26.1 + j29.8 0.467 107.4 1500 37.3 + j33.9 0.386 89.3 1850 57.4 + j29.7 0.275 60.6 2150 71.3 + j10.1 0.193 20.6 2450 64.6 – j13.9 0.175 –36.8 2650 53.0 – j21.8 0.209 –70.3 3000 35.0 – j21.2 0.297 –111.2 3500 20.7 – j9.0 0.431 –155.8 4000 14.2 + j6.2 0.564 164.8 5000 10.4 + j31.9 0.745 113.3 LO Input Port The mixer’s LO input, shown in Figure 5, consists of an integrated transformer and high speed limiting differential amplifiers. The amplifiers are designed to precisely drive the mixer for the highest linearity and the lowest noise figure. An internal DC blocking capacitor in series with the transformer’s primary eliminates the need for an external blocking capacitor. The LO input is internally matched from 1.2GHz to 5GHz, although the maximum useful frequency is limited to 3.5GHz by the internal amplifiers. The input match can be shifted down, as low as 750MHz, with a single shunt capacitor (C4) on Pin 15. One example is plotted in Figure 6 where C4 = 2.7pF produces an 850MHz to 1.2GHz match. LO input matching below 750MHz requires the series inductor (L4)/shunt capacitor (C4) network shown in Figure 5. Two examples are plotted in Figure 6 where L4 = 3.9nH/C4 = 5.6pF produces a 650MHz to 830MHz match and L4 = 6.8nH/C4 = 10pF produces a 540MHz to 640MHz match. The evaluation boards do not include pads for L4, so the circuit trace needs to be cut near Pin 15 to insert L4. A low cost multilayer chip inductor is adequate for L4. The optimum LO drive is –3dBm for LO frequencies above 1.2GHz, although the amplifiers are designed to accommodate several dB of LO input power variation without significant mixer performance variation. Below 1.2GHz, EXTERNAL MATCHING FOR LOW BAND ONLY LOIN TO MIXER L4 15 LO C4 VBIAS LIMITER VCC2 5527 F05 Figure 5. LO Input Schematic 0 –5 LO PORT RETURN LOSS (dB) at 4.5mm. This series transmission line/shunt capacitor matching topology allows the LT5527 to be used for multiple frequency standards without circuit board layout modifications. The series transmission line can also be replaced with a series chip inductor for a more compact layout. L4 = 6.8nH C4 = 10pF L4 = 0nH C4 = 2.7pF –10 NO EXTERNAL MATCHING –15 L4 = 3.9nH C4 = 5.6pF –20 –25 –30 0.1 1 LO FREQUENCY (GHz) 5 5527 F06 Figure 6. LO Input Return Loss 5527f 10 LT5527 U W U U APPLICATIO S I FOR ATIO 0dBm LO drive is recommended for optimum noise figure, although –3dBm will still deliver good conversion gain and linearity. Custom matching networks can be designed using the port impedance data listed in Table 2. This data is referenced to the LO pin with no external matching. Table 2. LO Input Impedance vs Frequency S11 output impedance is listed in Table 3. This data is referenced to the package pins (with no external components) and includes the effects of IC and package parasitics. The IF output can be matched for IF frequencies as low as several kHz or as high as 600MHz. Table 3. IF Output Impedance vs Frequency FREQUENCY (MHz) DIFFERENTIAL OUTPUT IMPEDANCE (RIF || XIF) FREQUENCY (MHz) INPUT IMPEDANCE MAG ANGLE 1 415||-j64k 50 30.4 – j355.7 0.977 –15.9 10 415||-j6.4k 300 8.7 – j52.2 0.847 –86.7 70 415||-j909 413||-j453 450 9.4 – j25.4 0.740 –124.8 140 600 11.5 – j8.9 0.635 –158.7 240 407||-j264 900 19.7 + j12.8 0.463 146.7 300 403||-j211 1200 34.3 + j24.3 0.330 106.9 380 395||-j165 1500 49.8 + j21.3 0.209 78.5 450 387||-j138 1850 53.8 + j8.9 0.093 61.7 500 381||-j124 2150 50.4 + j3.2 0.032 80.5 2450 45.1 + j0.3 0.052 176.5 2650 41.1 + j2.4 0.101 163.1 3000 41.9 + j8.1 0.124 129.8 3500 49.0 + j12.0 0.120 87.9 4000 55.4 + j8.6 0.096 53.2 5000 33.2 + j8.7 0.226 146.7 The following three methods of differential to singleended IF matching will be described: • Direct 8:1 transformer • Lowpass matching + 4:1 transformer • Discrete IF balun IF Output Port The IF outputs, IF+ and IF–, are internally connected to the collectors of the mixer switching transistors (see Figure 7). Both pins must be biased at the supply voltage, which can be applied through the center tap of a transformer or through matching inductors. Each IF pin draws 26mA of supply current (52mA total). For optimum singleended performance, these differential outputs should be combined externally through an IF transformer or a discrete IF balun circuit. The standard evaluation board (see Figure 1) includes an IF transformer for impedance transformation and differential to single-ended transformation. A second evaluation board (see Figure 2) realizes the same functionality with a discrete IF balun circuit. The IF output impedance can be modeled as 415Ω in parallel with 2.5pF at low frequencies. An equivalent small-signal model (including bondwire inductance) is shown in Figure 8. Frequency-dependent differential IF IF+ L1 4:1 11 C3 IF– IFOUT 50Ω VCC 10 L2 VCC 5527 F07 Figure 7. IF Output with External Matching 0.7nH RS 415Ω IF+ 11 2.5pF IF– 10 0.7nH 5527 F08 Figure 8. IF Output Small-Signal Model 5527f 11 LT5527 U W U U APPLICATIO S I FOR ATIO Direct 8:1 IF Transformer Matching For IF frequencies below 100MHz, the simplest IF matching technique is an 8:1 transformer connected across the IF pins. The transformer will perform impedance transformation and provide a single-ended 50Ω output. No other matching is required. Measured performance using this technique is shown in Figure 9. This matching is easily implemented on the standard evaluation board by shorting across the pads for L1 and L2 and replacing the 4:1 transformer with an 8:1 (C3 not installed). 25 IIP3 21 19 17 15 SSB NF 13 RF = 900MHz HIGH SIDE LO AT 0dBm VCC = 5V DC TA = 25°C C4 = 2.7pF, C5 = 3.9pF Table 4. IF Matching Element Values PLOT IF FREQUENCY (MHz) L1, L2 (nH) C3 (pF) IF TRANSFORMER 1 1 to 100 Short — TC8-1 (8:1) 2 140 120 — ETC4-1-2 (4:1) 3 190 110 2.7 ETC4-1-2 (4:1) 4 240 82 2.7 ETC4-1-2 (4:1) 5 380 56 2.2 ETC4-1-2 (4:1) 6 450 43 2.2 ETC4-1-2 (4:1) 0 11 9 –5 7 GC 5 3 1 10 20 30 40 50 60 70 80 90 100 IF OUTPUT FREQUENCY (MHz) 5527 F09 Figure 9. Typical Conversion Gain, IIP3 and SSB NF Using an 8:1 IF Transformer IF PORT RETURN LOSS (dB) GC (dB), IIP3 (dBm), SSB NF (dB) 23 chip inductors (L1 and L2) improve the mixer’s conversion gain by a few tenths of a dB, but have little effect on linearity. Measured output return losses for each case are plotted in Figure 10 for the simple 8:1 transformer method and for the lowpass/4:1 transformer method. –10 –15 –20 2 –25 4 5 6 1 3 –30 Lowpass + 4:1 IF Transformer Matching The lowest LO-IF leakage and wide IF bandwidth are realized by using the simple, three element lowpass matching network shown in Figure 7. Matching elements C3, L1 and L2, in conjunction with the internal 2.5pF capacitance, form a 400Ω to 200Ω lowpass matching network which is tuned to the desired IF frequency. The 4:1 transformer then transforms the 200Ω differential output to a 50Ω single-ended output. This matching network is most suitable for IF frequencies above 40MHz or so. Below 40MHz, the value of the series inductors (L1 and L2) becomes unreasonably high, and could cause stability problems, depending on the inductor value and parasitics. Therefore, the 8:1 transformer technique is recommended for low IF frequencies. Suggested lowpass matching element values for several IF frequencies are listed in Table 4. High-Q wire-wound 0 50 100 150 200 250 300 350 400 450 500 IF FREQUENCY (MHz) 5527 F10 Figure 10. IF Output Return Losses with Lowpass/Transformer Matching Discrete IF Balun Matching For many applications, it is possible to replace the IF transformer with the discrete IF balun shown in Figure 2. The values of L1, L2, C6 and C7 are calculated to realize a 180 degree phase shift at the desired IF frequency and provide a 50Ω single-ended output, using the equations listed below. Inductor L3 is calculated to cancel the internal 2.5pF capacitance. L3 also supplies bias voltage to the IF+ pin. Low cost multilayer chip inductors are adequate for L1 and L2. A high Q wire-wound chip inductor is recommended for L3 to maximize conversion gain and minimize DC voltage drop to the IF+ pin. C3 is a DC blocking capacitor. 5527f 12 LT5527 U W U U APPLICATIO S I FOR ATIO IF PORT RETURN LOSS (dB) –5 1 ωIF • RIF • ROUT XIF L3 = ωIF –10 –15 190MHz –20 240MHz Discrete IF balun element values for four common IF frequencies are listed in Table 5. The corresponding measured IF output return losses are shown in Figure 11. The values listed in Table 5 differ from the calculated values slightly due to circuit board and component parasitics. Typical conversion gain, IIP3 and LO-IF leakage, versus RF input frequency, for all four IF frequency examples is shown in Figure 12. Typical conversion gain, IIP3 and noise figure versus IF output frequency for the same circuits are shown in Figure 13. Table 5. Discrete IF Balun Element Values (ROUT = 50Ω) IF FREQUENCY (MHz) L1, L2 (nH) C6, C7 (pF) L3 (nH) 190 120 6.8 220 240 100 4.7 220 380 56 3 68 450 47 2.7 47 For fully differential IF architectures, the IF transformer can be eliminated. An example is shown in Figure 14, where the mixer’s IF output is matched directly into a SAW filter. Supply voltage to the mixer’s IF pins is applied –30 50 100 150 200 250 300 350 400 450 500 550 IF FREQUENCY (MHz) 5527 F11 Figure 11. IF Output Return Losses with Discrete Balun Matching 26 0 24 22 IIP3 –10 20 190IF 240IF 380IF 450IF 18 16 14 LOW SIDE LO (–3dBm) –20 TA = 25°C –30 12 10 LO-IF 8 6 4 –50 GC 2 1700 –40 LO-IF LEAKAGE (dBm) Compared to the lowpass/4:1 transformer matching technique, this network delivers approximately 0.8dB higher conversion gain (since the IF transformer loss is eliminated) and comparable noise figure and IIP3. At a ±15% offset from the IF center frequency, conversion gain and noise figure degrade about 1dB. Beyond ±15%, conversion gain decreases gradually but noise figure increases rapidly. IIP3 is less sensitive to bandwidth. Other than IF bandwidth, the most significant difference is LO-IF leakage, which degrades to approximately – 38dBm compared to the superior performance realized with the lowpass/4:1 transformer matching. 380MHz 450MHz –25 GC (dB), IIP3 (dBm) C6,C7 = 0 RIF • ROUT ωIF 1900 2300 2500 2100 RF INPUT FREQUENCY (MHz) –60 2700 5527 F12 Figure 12. Conversion Gain, IIP3 and LO-IF Leakage vs RF Input Frequency Using Discrete IF Balun Matching GC, SSB NF (dB), IIP3 (dBm) L1, L2 = 26 24 22 IIP3 20 LOW SIDE LO (–3dBm) TA = 25°C 18 16 14 12 SSB NF 190IF 10 240IF 8 380IF 6 450IF GC 4 2 0 150 200 250 300 350 400 450 500 550 IF OUTPUT FREQUENCY (MHz) 5527 F13 Figure 13. Conversion Gain, IIP3 and SSB NF vs IF Output Frequency Using Discrete IF Balun Matching 5527f 13 LT5527 U W U U APPLICATIO S I FOR ATIO through matching inductors in a band-pass IF matching network. The values of L1, L2 and C3 are calculated to resonate at the desired IF frequency with a quality factor that satisfies the required IF bandwidth. The L and C values are then adjusted to account for the mixer’s internal 2.5pF capacitance and the SAW filter’s input capacitance. In this case, the differential IF output impedance is 400Ω since the bandpass network does not transform the impedance. IF L1 + SAW FILTER IF AMP C3 IF – SUPPLY DECOUPLING L2 5527 F14 VCC Figure 14. Bandpass IF Matching for Differential IF Architectures Additional matching elements may be required if the SAW filter’s input impedance is less than or greater than 400Ω. Contact the factory for application assistance. Standard Evaluation Board Layout Discrete IF Evaluation Board Layout 5527f 14 LT5527 U PACKAGE DESCRIPTIO UF Package 16-Lead Plastic QFN (4mm × 4mm) (Reference LTC DWG # 05-08-1692) 0.72 ±0.05 4.35 ± 0.05 2.15 ± 0.05 2.90 ± 0.05 (4 SIDES) PACKAGE OUTLINE 0.30 ±0.05 0.65 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS BOTTOM VIEW—EXPOSED PAD 4.00 ± 0.10 (4 SIDES) R = 0.115 TYP 0.75 ± 0.05 15 PIN 1 NOTCH R = 0.20 TYP OR 0.25 × 45° CHAMFER 16 0.55 ± 0.20 PIN 1 TOP MARK (NOTE 6) 1 2.15 ± 0.10 (4-SIDES) 2 (UF) QFN 09-04 0.200 REF 0.00 – 0.05 0.30 ± 0.05 0.65 BSC 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 5527f 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 LT5527 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, 17dBm IIP3, Integrated LO Buffer LT5514 Ultralow Distortion, IF Amplifier/ADC Driver with Digitally Controlled Gain 850MHz Bandwidth, 47dBm OIP3 at 100MHz, 10.5dB to 33dB Gain Control Range 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 50Ω 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 50Ω Matching, Single-Ended LO and RF Ports Operation LT5521 10MHz to 3700MHz High Linearity Upconverting Mixer 24.2dBm IIP3 at 1.95GHz, NF = 12.5dB, 3.15V to 5.25V Supply, Single-Ended LO Port Operation LT5522 400MHz to 2.7GHz High Signal Level Downconverting Mixer 4.5V to 5.25V Supply, 25dBm IIP3 at 900MHz, NF = 12.5dB, 50Ω Single-Ended RF and LO Ports LT5524 Low Power, Low Distortion ADC Driver with Digitally 450MHz Bandwidth, 40dBm OIP3, 4.5dB to 27dB Gain Control Programmable Gain LT5525 High Linearity, Low Power Downconverting Mixer Single-Ended 50Ω RF and LO Ports, 17.6dBm IIP3 at 1900MHz, ICC = 28mA LT5526 High Linearity, Low Power Downconverting Mixer 3V to 5.3V Supply, 16.5dBm IIP3, 100kHz to 2GHz RF, NF = 11dB, ICC = 28mA, –65dBm LO-RF Leakage LT5528 1.5GHz to 2.4GHz High Linearity Direct I/Q Modulator 21.8dBm OIP3 at 2GHz, –159dBm/Hz Noise Floor, 50Ω Interface at all 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 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 RF Power Detector with 60dB Dynamic Range ±1dB Output Variation over Temperature, 38ns Response Time LTC5536 Precision 600MHz to 7GHz RF Detector with Fast Compatator Output 25ns Response Time, Comparator Reference Input, Latch Enable Input, –26dBm to +12dBm Input Range ® Low Voltage RF Building Block LT5546 500MHz Quadrature Demodulator with VGA and 17MHz Baseband Bandwidth 17MHz Baseband Bandwidth, 40MHz to 500MHz IF, 1.8V to 5.25V Supply, –7dB to 56dB Linear Power Gain Wide Bandwidth ADCs LTC1749 12-Bit, 80Msps 500MHz BW S/H, 71.8dB SNR LTC1750 14-Bit, 80Msps 500MHz BW S/H, 75.5dB SNR 5527f 16 Linear Technology Corporation LT/TP 0305 500 • PRINTED IN THE USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2005