LTC5544 4GHz to 6GHz High Dynamic Range Downconverting Mixer Description Features Conversion Gain: 7.4dB at 5250MHz n IIP3: 25.9dBm at 5250MHz n Noise Figure: 11.3dB at 5250MHz n High Input P1dB n IF Bandwidth Up to 1GHz n 640mW Power Consumption n Shutdown Pin n 50Ω Single-Ended RF and LO Inputs n+2dBm LO Drive Level n High LO-RF and LO-IF Isolation n–40°C to 105°C Operation (T ) C n Small Solution Size n16-Lead (4mm × 4mm) QFN package The LTC®5544 is part of a family of high dynamic range, high gain passive downconverting mixers covering the 600MHz to 6GHz frequency range. The LTC5544 is optimized for 4GHz to 6GHz RF applications. The LO frequency must fall within the 4.2GHz to 5.8GHz range for optimum performance. A typical application is a WiMAX receiver with a 5.15GHz to 5.35GHz RF input and low side LO. n The LTC5544 is designed for 3.3V operation, however; the IF amplifier can be powered with 5V for the higher P1dB. The LTC5544’s high level of integration minimizes the total solution cost, board space and system-level variation, while providing the highest dynamic range for demanding receiver applications. Applications High Dynamic Range Downconverting Mixer Family 5GHz WiMAX/WLAN Receiver n4.9GHz Public Safety Bands n4.9GHz to 6GHz Military Communications n Point-to-Point Broadband Communications n Radar Systems n L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. PART# RF RANGE LO RANGE LTC5540 600MHz to 1.3GHz 700MHz to 1.2GHz LTC5541 1.3GHz to 2.3GHz 1.4GHz to 2.0GHz LTC5542 1.6GHz to 2.7GHz 1.7GHz to 2.5GHz LTC5543 2.3GHz to 4GHz 2.4GHz to 3.6GHz LTC5544 4GHz to 6GHz 4.2GHz to 5.8GHz Typical Application Wideband Conversion Gain, IIP3 and NF vs IF Output Frequency Wideband Receiver 240MHz SAW 1nF 22pF 1µF RF 5150MHz TO 5350MHz LTC5544 1.2pF SYNTH LO 2.2nH VCC1 VCC 3.3V LO 5010MHz fLO = 5010MHz 7.9 PLO = 2dBm RF = 5250 ±35MHz 7.7 TEST CIRCUIT IN FIGURE 1 7.5 7.3 6.9 6.5 205 VCC2 25 23 21 19 GC 17 7.1 6.7 BIAS SHDN 27 IIP3 8.1 RF SHDN (0V/3.3V) 29 8.3 IF – IF LNA 8.5 ADC 15 IIP3 (dBm), SSB NF (dB) IF+ IMAGE BPF 0.6pF IF AMP 1nF 150nH 150nH LTC2208 GC (dB) VCCIF 3.3V or 5V LTC6416 13 NF 11 215 225 235 245 255 265 IF OUTPUT FREQUENCY (MHz) 9 275 5544 TA01b 1µF 22pF 5544 TA01a 5544f 1 LTC5544 Absolute Maximum Ratings Pin Configuration (Note 1) Mixer Supply Voltage (VCC1, VCC2)............................4.0V IF Supply Voltage (IF+, IF –).......................................5.5V Shutdown Voltage (SHDN).................–0.3V to VCC +0.3V IF Bias Adjust Voltage (IFBIAS)..........–0.3V to VCC +0.3V LO Bias Adjust Voltage (LOBIAS).......–0.3V to VCC +0.3V LO Input Power (4GHz to 6GHz)............................+9dBm LO Input DC Voltage................................................ ±0.1V RF Input Power (4GHz to 6GHz).......................... +15dBm RF Input DC Voltage................................................ ±0.1V TEMP Diode Continuous DC Input Current..............10mA TEMP Diode Input Voltage......................................... ±1V Operating Temperature Range (TC)......... –40°C to 105°C Storage Temperature Range................... –65°C to 150°C Junction Temperature (TJ)..................................... 150°C IFGND IF– IF+ IFBIAS TOP VIEW 16 15 14 13 GND 1 12 TEMP RF 2 11 GND 17 GND CT 3 10 LO SHDN 4 6 7 8 VCC1 LOBIAS VCC2 GND 9 5 GND UF PACKAGE 16-LEAD (4mm × 4mm) PLASTIC QFN TJMAX = 150°C, θJC = 8°C/W EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB Order Information LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION CASE TEMPERATURE RANGE LTC5544IUF#PBF LTC5544IUF#TRPBF 5544 16-Lead (4mm x 4mm) Plastic QFN –40°C to 105°C Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on non-standard lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ AC Electrical Characteristics VCC = 3.3V, VCCIF = 3.3V, SHDN = Low, TC = 25°C, PLO = 2dBm, unless otherwise noted. Test circuit shown in Figure 1. (Notes 2, 3) PARAMETER CONDITIONS MIN LO Input Frequency Range RF Input Frequency Range Low Side LO High Side LO IF Output Frequency Range Requires External Matching RF Input Return Loss ZO = 50Ω, 4000MHz to 6000MHz LO Input Return Loss ZO = 50Ω, 4200MHz to 5800MHz IF Output Impedance Differential at 240MHz LO Input Power fLO = 4200MHz to 5800MHz TYP MAX 4200 to 5800 MHz 4200 to 6000 4000 to 5800 MHz MHz 5 to 1000 MHz >12 –1 UNITS dB >12 dB 332Ω || 1.7pF R||C 2 5 dBm LO to RF Leakage fLO = 4200MHz to 5800MHz, Requires C2 <–30 dBm LO to IF Leakage fLO = 4200MHz to 5800MHz <–21 dBm RF to LO Isolation fRF = 4000MHz to 6000MHz >38 dB RF to IF Isolation fRF = 4000MHz to 6000MHz >29 dB 5544f 2 LTC5544 AC Electrical Characteristics VCC = 3.3V, VCCIF = 3.3V, SHDN = Low, TC = 25°C, PLO = 2dBm, PRF = –3dBm (–3dBm/tone for 2-tone tests),unless otherwise noted. Test circuit shown in Figure 1. (Notes 2, 3) Low Side LO Downmixer Application: RF = 4200MHz to 6000MHz, IF = 240MHz, fLO = fRF – fIF PARAMETER CONDITIONS Conversion Gain RF = 4900MHz RF = 5250MHz RF = 5800MHz MIN TYP 6.0 7.9 7.4 6.4 MAX UNITS Conversion Gain Flatness RF = 5250MHz ±30MHz, LO = 5010MHz, IF = 240 ±30MHz ±0.15 dB Conversion Gain vs Temperature TC = –40°C to 105°C, RF = 5250MHz –0.007 dB/°C 2-Tone Input 3rd Order Intercept (∆f = 2MHz) RF = 4900MHz RF = 5250MHz RF = 5800MHz 25.4 25.9 25.8 dBm 2-Tone Input 2nd Order Intercept (∆f = 241MHz, fIM2 = fRF1 – fRF2) fRF1 = 5371MHz, fRF2 = 5130MHz, fLO = 5010MHz 43.2 dBm SSB Noise Figure RF = 4900MHz RF = 5250MHz RF = 5800MHz 10.3 11.3 12.8 dB SSB Noise Figure Under Blocking fRF = 5250MHz, fLO = 5010MHz, fBLOCK = 4910MHz, PBLOCK = 5dBm 16.9 dB 2RF – 2LO Output Spurious Product (fRF = fLO + fIF /2) fRF = 5130MHz at –10dBm, fLO = 5010MHz, fIF = 240MHz –58.3 dBc 3RF – 3LO Output Spurious Product (fRF = fLO + fIF /3) fRF = 5090MHz at –10dBm, fLO = 5010MHz, fIF = 240MHz –77 dBc Input 1dB Compression RF = 5250MHz, VCCIF = 3.3V RF = 5250MHz, VCCIF = 5V 11.4 14.6 dBm dB High Side LO Downmixer Application: RF = 4000MHz to 5800MHz, IF = 240MHz, fLO = fRF + fIF PARAMETER CONDITIONS Conversion Gain RF = 4500MHz RF = 4900MHz RF = 5250MHz MIN TYP 8.0 7.7 7.3 MAX UNITS dB Conversion Gain Flatness RF = 4900MHz ±30MHz, LO = 5356MHz, IF = 456 ±30MHz ±0.15 dB Conversion Gain vs Temperature TC = –40°C to 105°C, RF = 4900MHz –0.005 dB/°C 2-Tone Input 3rd Order Intercept (∆f = 2MHz) RF = 4500MHz RF = 4900MHz RF = 5250MHz 24.2 25.1 24.0 dBm 2-Tone Input 2nd Order Intercept (∆f = 241MHz, fIM2 = fRF2 – fRF1) fRF1 = 4779MHz, fRF2 = 5020MHz, fLO = 5140MHz 39.8 dBm SSB Noise Figure RF = 4500MHz RF = 4900MHz RF = 5250MHz 10.7 11.0 11.7 dB 2LO – 2RF Output Spurious Product (fRF = fLO – fIF/2) fRF = 5020MHz at –10dBm, fLO = 5140MHz fIF = 240MHz –55 dBc 3LO – 3RF Output Spurious Product (fRF = fLO – fIF/3) fRF = 5060MHz at –10dBm, fLO = 5140MHz fIF = 240MHz –75 dBc Input 1dB Compression RF = 4900MHz, VCCIF = 3.3V RF = 4900MHz, VCCIF = 5V 11.3 14.5 dBm 5544f 3 LTC5544 DC Electrical Characteristics noted. Test circuit shown in Figure 1. (Note 2) PARAMETER VCC = 3.3V, VCCIF = 3.3V, SHDN = Low, TC = 25°C, unless otherwise CONDITIONS MIN TYP MAX UNITS VCC Supply Voltage (Pins 5 and 7) 3.1 3.3 3.5 V VCCIF Supply Voltage (Pins 14 and 15) 3.1 3.3 5.3 V 96 98 194 116 122 238 mA 500 µA 0.3 V 30 µA Power Supply Requirements (VCC, VCCIF) VCC Supply Current (Pins 5 + 7) VCCIF Supply Current (Pins 14 + 15) Total Supply Current (VCC + VCCIF) Total Supply Current – Shutdown SHDN = High Shutdown Logic Input (SHDN) Low = On, High = Off SHDN Input High Voltage (Off) 3.0 V SHDN Input Low Voltage (On) SHDN Input Current –0.3V to VCC + 0.3V –20 Turn On Time 0.6 µs Turn Off Time 0.6 µs Temperature Sensing Diode (TEMP) DC Voltage at TJ = 25°C IIN = 10µA IIN = 80µA 726.1 782.5 mV mV Voltage Temperature Coefficient IIN = 10µA IIN = 80µA –1.73 –1.53 mV/°C mV/°C Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The LTC5544 is guaranteed functional over the –40°C to 105°C case temperature range. Note 3: SSB Noise Figure measurements performed with a small-signal noise source, bandpass filter and 6dB matching pad on RF input, 6dB matching pad on the LO input, bandpass filter on the IF output and no other RF signals applied. Typical DC Performance Characteristics VCC Supply Current vs Supply Voltage (Mixer and LO Buffer) VCCIF Supply Current vs Supply Voltage (IF Amplifier) 102 TC = 105°C 96 TC = 25°C 94 TC = –40°C 3.1 3.2 3.3 3.4 3.5 VCC SUPPLY VOLTAGE (V) TC = 105°C TC = 85°C 115 105 TC = 25°C 95 TC = –40°C 85 3.6 5544 G01 75 3.0 3.3 3.6 3.9 4.2 4.5 4.8 5.1 5.4 VCCIF SUPPLY VOLTAGE (V) 5544 G02 Total Supply Current vs Temperature (VCC + VCCIF) 210 SUPPLY CURRENT (mA) SUPPLY CURRENT (mA) SUPPLY CURRENT (mA) 125 TC = 85°C 98 90 3.0 220 135 100 92 SHDN = Low, Test circuit shown in Figure 1. VCC = 3.3V, VCCIF = 5V (DUAL SUPPLY) 200 190 VCC = VCCIF = 3.3V (SINGLE SUPPLY) 180 170 –40 –20 0 20 40 60 80 CASE TEMPERATURE (°C) 100 120 5544 G03 5544f 4 LTC5544 Typical AC Performance Characteristics Low Side LO VCC = 3.3V, VCCIF = 3.3V, SHDN = Low, TC = 25°C, PLO = 2dBm, PRF = –3dBm (–3dBm/tone for two-tone IIP3 tests, ∆f = 2MHz), IF = 240MHz, unless otherwise noted. Test circuit shown in Figure 1. Conversion Gain and IIP3 vs RF Frequency Conversion Gain and IIP3 vs RF Frequency IIP3 27 13 25 21 9 GC 7 19 23 21 7 IIP3 16 15 TC = –40°C 11 TC = 25°C TC = 85°C TC = 105°C 9 INPUT P1dB (dBm) 13 GC (dB) IIP3 (dBm) 9 GC Input P1dB vs RF Frequency 15 27 GC 7 19 14 VCCIF = 5V 13 12 11 VCCIF = 3.3V PLO = –1dBm PLO = 2dBm PLO = 5dBm 10 9 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 RF FREQUENCY (GHz) 5 17 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 RF FREQUENCY (GHz) 5544 G07 5544 G06 SSB NF and DSB NF vs RF Frequency 5250MHz Conversion Gain, IIP3 and NF vs LO Power 16 28 SSB NF GC (dB), IIP3 (dBm) DSB NF 8 6 4 2 20 24 12 10 22 IIP3 26 TC = –40°C TC = 25°C TC = 85°C TC = 105°C 0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 RF FREQUENCY (GHz) 5544 G08 18 16 22 20 14 NF 12 18 10 16 14 12 10 GC 8 6 –3 –2 –1 TC = –40°C 8 TC = 25°C 6 TC = 85°C 4 0 1 2 3 4 5 LO INPUT POWER (dBm) SSB NF (dB) SSB NF, DSB NF (dB) 14 11 5544 G05 Conversion Gain and IIP3 vs RF Frequency 21 13 VCC = VCCIF VCC = 3.1V VCC = 3.3V VCC = 3.5V 5 17 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 RF FREQUENCY (GHz) 5544 G04 23 IIP3 19 5 17 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 RF FREQUENCY (GHz) 25 15 GC (dB) PLO = –1dBm PLO = 2dBm 11 PLO = 5dBm 23 GC (dB) IIP3 (dBm) 25 15 IIP3 (dBm) 27 2 6 7 0 5544 G09 5544f 5 LTC5544 Typical AC Performance Characteristics Low Side LO (continued) VCC = 3.3V, VCCIF = 3.3V, SHDN = Low, TC = 25°C, PLO = 2dBm, PRF = –3dBm (–3dBm/tone for two-tone IIP3 tests, Δf = 2MHz), IF = 240MHz, unless otherwise noted. Test circuit shown in Figure 1. 0 RF = 5250MHz VCCIF = 5V VCCIF = 3.3V 22 20 18 P1dB 16 14 12 –20 –30 8 –50 –5 15 35 55 75 CASE TEMPERATURE (°C) 95 –80 –12 –9 115 5544 G10 SSB Noise Figure vs RF Blocker Level LO TO RF LEAKAGE (dBm) SSB NF (dB) PLO = –1dBm 16 15 PLO = 2dBm 14 13 12 PLO = 5dBm 11 10 –25 –20 –15 –10 –5 0 RF BLOCKER POWER (dBm) –6 5544 G11 –20 –30 RF = 5250MHz 20 25 20 15 10 6 5544 G12 RF TO LO 40 RF TO IF 4.4 C2 = 0.4pF C2 = 0.6pF 4.6 4.8 5.0 5.2 5.4 LO FREQUENCY (GHz) 5.6 TC = 85°C TC = 25°C TC = –40°C 5544 G14 45 RF = 5250MHz 15 10 5 LO TO IF 20 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 RF/LO FREQUENCY (GHz) 5544 G15 5.8 5250MHz IIP3 Histogram 25 –2 0 2 4 LO INPUT POWER (dBm) RF/LO Isolation 30 –40 5544 G13 –4 50 C2 = OPEN –50 4.2 5 DISTRIBUTION (%) DISTRIBUTION (%) 3RF – 3LO (RF = 5090MHz) 60 C2 = 1pF 30 40 35 5250MHz SSB NF Histogram TC = 85°C TC = 25°C TC = –40°C RF = 5250MHz 30 25 20 15 10 5 5 0 –70 –10 5250MHz Conversion Gain Histogram TC = 85°C TC = 25°C TC = –40°C –60 –80 12 15 2RF – 2LO (RF = 5130MHz) LO to RF Leakage vs LO Frequency RF = 5250MHz 19 LO = 5010MHz BLOCKER = 4910MHz 18 17 –6 –3 0 3 6 9 RF INPUT POWER (dBm) RF = 5250MHz PRF = –10dBm –50 0 20 35 3RF – 3LO (RF = 5090MHz) –70 GC 6 –45 –25 40 2RF – 2LO (RF = 5130MHz) –40 –60 10 45 LO = 5010MHz –10 ISOLATION (dB) 24 –40 IFOUT (RF = 5250MHz) 10 OUTPUT POWER (dBm) GC (dB), IIP3 (dBm), P1dB (dBm) 20 IIP3 26 2 × 2 and 3 × 3 Spurs vs LO Power DISTRIBUTION (%) 28 Single-Tone IF Output Power, 2 × 2 and 3 × 3 Spurs vs RF Input Power RELATIVE SPUR LEVEL (dBc) Conversion Gain, IIP3 and RF Input P1dB vs Temperature 6.8 6.9 7.0 7.1 7.2 7.3 7.4 7.5 7.6 7.7 7.8 7.9 CONVERSION GAIN (dB) 5544 G16 0 23.7 24.1 24.5 24.9 25.3 25.7 26.1 26.5 26.9 IIP3 (dBm) 5544 G17 0 9.9 10.3 10.7 11.1 11.5 11.9 12.3 12.7 SSB NOISE FIGURE (dB) 5544 G18 5544f 6 LTC5544 Typical AC Performance Characteristics High Side LO VCC = 3.3V, VCCIF = 3.3V, SHDN = Low, TC = 25°C, PLO = 2dBm, PRF = –3dBm (–3dBm/tone for two-tone IIP3 tests, Δf = 2MHz), IF = 240MHz, unless otherwise noted. Test circuit shown in Figure 1. Conversion Gain and IIP3 vs RF Frequency 24 13 24 13 22 11 22 11 18 GC 7 PLO = –1dBm PLO = 2dBm PLO = 5dBm 20 18 5 16 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 RF FREQUENCY (GHz) Input P1dB vs RF Frequency 15 11 TC = –40°C TC = 25°C 9 TC = 85°C TC = 105°C GC (dB) 22 INPUT P1dB (dBm) 13 24 IIP3 (dBm) 7 16 15 IIP3 GC VCC = VCCIF VCC = 3.1V VCC = 3.3V VCC = 3.5V 5544 G20 Conversion Gain and IIP3 vs RF Frequency 20 9 GC 5 16 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 RF FREQUENCY (GHz) 5544 G19 26 15 IIP3 GC (dB) 9 20 IIP3 (dBm) 26 IIP3 GC (dB) 15 26 IIP3 (dBm) Conversion Gain and IIP3 vs RF Frequency 7 18 VCCIF = 5V 14 13 12 VCCIF = 3.3V 11 10 PLO = –1dBm PLO = 2dBm PLO = 5dBm 9 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 RF FREQUENCY (GHz) 5544 G22 5 16 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 RF FREQUENCY (GHz) 5544 G21 5250MHz Conversion Gain, IIP3 and NF vs LO Power SSB NF and DSB NF vs RF Frequency 25 16 SSB NF GC (dB), IIP3 (dBm) DSB NF 8 6 4 2 16 21 12 10 18 IIP3 TC = –40°C TC = 25°C TC = 85°C TC = 105°C 0 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 RF FREQUENCY (GHz) 5544 G23 19 14 NF 17 12 15 10 13 11 9 GC 7 5 –3 –2 –1 TC = –40°C 8 TC = 25°C 6 TC = 85°C 4 0 1 2 3 4 5 LO INPUT POWER (dBm) SSB NF (dB) SSB NF, DSB NF (dB) 14 20 23 2 6 7 0 5544 G24 5544f 7 LTC5544 Pin Functions GND (Pins 1, 8, 9, 11, Exposed Pad Pin 17): Ground. These pins must be soldered to the RF ground plane on the circuit board. The exposed pad metal of the package provides both electrical contact to ground and good thermal contact to the printed circuit board. nected and must be externally connected to a regulated 3.3V supply, with bypass capacitors located close to the pins. Typical current consumption is 96mA. RF (Pin 2): Single-Ended Input for the RF Signal. This pin is internally connected to the primary side of the RF input transformer, which has low DC resistance to ground. A series DC-blocking capacitor should be used to avoid damage to the integrated transformer when DC voltage is present at the RF input. The RF input is impedance matched, as long as the LO input is driven with a 2dBm ±5dB source between 4.2GHz and 5.8GHz. LO (Pin 10): Single-Ended Input for the Local Oscillator. This pin is internally connected to the primary side of the RF input transformer, which has low DC resistance to ground. A series DC blocking capacitor must be used to avoid damage to the integrated transformer if DC voltage is present at the LO input. LOBIAS (Pin 6): This Pin Allows Adjustment of the LO Buffer Current. Typical DC voltage is 2.2V. TEMP (Pin 12): Temperature Sensing Diode. This pin is connected to the anode of a diode that may be used to measure the die temperature, by forcing a current and measuring the voltage. CT (Pin 3): RF Transformer Secondary Center-Tap. This pin may require a bypass capacitor to ground. See the Applications Information section. This pin has an internally generated bias voltage of 1.2V. It must be DC-isolated from ground and VCC. IFGND (Pin 13): DC Ground Return for the IF Amplifier. This pin must be connected to ground to complete the IF amplifier’s DC current path. Typical DC current is 98mA. SHDN (Pin 4): Shutdown Pin. When the input voltage is less than 0.3V, the IC is enabled. When the input voltage is greater than 3V, the IC is disabled. Typical SHDN pin input current is less than 10μA. This pin must not be allowed to float. IF – (Pin 14) and IF + (Pin 15): Open-Collector Differential Outputs for the IF Amplifier. These pins must be connected to a DC supply through impedance matching inductors, or a transformer center-tap. Typical DC current consumption is 49mA into each pin. VCC1 (Pin 5) and VCC2 (Pin 7): Power Supply Pins for the LO Buffer and Bias Circuits. These pins are internally con- IFBIAS (Pin 16): This Pin Allows Adjustment of the IF Amplifier Current. Typical DC voltage is 2.1V. Block Diagram 16 15 14 IFBIAS IF + 17 13 IF – IFGND IF AMP 2 3 4 EXPOSED PAD LO RF LO AMP CT SHDN TEMP 12 10 PASSIVE MIXER BIAS VCC2 VCC1 5 7 LOBIAS 6 5544 BD GND PINS ARE NOT SHOWN 5544f 8 LTC5544 Test Circuit IFOUT 240MHz 50Ω 4:1 T1 C5 L1 VCCIF 3.1V TO 5.3V L2 C8 C4 16 15 IFBIAS 1 GND 14 IF+ IF – LTC5544 13 IFGND TEMP 12 C1 RFIN 50Ω 2 RF GND 11 L4 C2 SHDN (0V/3.3V) 17 GND 3 CT 4 SHDN LOIN 50Ω GND 9 VCC1 LOBIAS 6 5 VCC 3.1V TO 3.5V VCC2 GND 8 7 C6 5544 F01 C7 RF 0.015” GND DC1885A BOARD BIAS STACK-UP GND (NELCO N4000-13) 0.062” 0.015” L1, L2 vs IF Frequencies C3 LO 10 REF DES VALUE SIZE COMMENTS C1 0.6pF 0402 AVX ACCU-P C2 Open 0402 IF (MHz) L1, L2 (nH) 140 220 190 150 C3 1.2pF 0402 AVX ACCU-P 240 150 C4, C6 22pF 0402 AVX 305 82 C5 1000pF 0402 AVX 380 56 C7, C8 1µF 0603 AVX 456 39 L1, L2 150nH 0603 Coilcraft 0603CS L4 2.2nH 0402 Coilcraft 0402HP T1 TC4-1W-7ALN+ Mini-Circuits Note: For IF = 250MHz to 500MHz, use TC4-1W-17LN+ for T1 Figure 1. Standard Downmixer Test Circuit Schematic (240MHz IF) 5544f 9 LTC5544 Applications Information Introduction The LTC5544 consists of a high linearity passive doublebalanced mixer core, IF buffer amplifier, LO buffer amplifier and bias/shutdown circuits. See the Block Diagram section for a description of each pin function. The RF and LO inputs are single-ended. The IF output is differential. Low side or high side LO injection can be used. The evaluation circuit, shown in Figure 1, utilizes bandpass IF output matching and an IF transformer to realize a 50Ω single-ended IF output. The evaluation board layout is shown in Figure 2. For the RF input to be matched, the LO input must be driven. A broadband input match is realized with C1 = 0.6pF and L4 = 2.2nH. The measured RF input return loss is shown in Figure 4 for LO frequencies of 4.4GHz, 5GHz and 5.6GHz. These LO frequencies correspond to the lower, middle and upper values of the LO range. As shown in Figure 4, the RF input impedance is somewhat dependent on LO frequency. The RF input impedance and input reflection coefficient, versus RF frequency, is listed in Table 1. The reference plane for this data is Pin 2 of the IC, with no external matching, and the LO is driven at 5GHz. LTC5544 TO MIXER RFIN C1 2 RF L4 3 CT C2 5544 F02 5544 F03 Figure 2. Evaluation Board Layout Figure 3. RF Input Schematic RF Input The secondary winding of the RF transformer is internally connected to the passive mixer. The center-tap of the transformer secondary is connected to Pin 3 (CT) to allow the connection of bypass capacitor, C2. The value of C2 is LO frequency-dependent and can be tuned for better LO leakage performance. When used, C2 should be located within 2mm of Pin 3 for proper high frequency decoupling. The nominal DC voltage on the CT pin is 1.2V. 10 0 5 RF PORT RETURN LOSS (dB) The mixer’s RF input, shown in Figure 3, is connected to the primary winding of an integrated transformer. A 50Ω match is realized with a series capacitor (C1) and a shunt inductor (L4). The primary side of the RF transformer is DC-grounded internally and the DC resistance of the primary is approximately 2.4Ω. A DC blocking capacitor is needed if the RF source has DC voltage present. 10 LO = 4.4GHz 15 20 25 LO = 5.6GHz 30 LO = 5GHz 35 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 RF FREQUENCY (GHz) 5544 F04 Figure 4. RF Input Return Loss 5544f LTC5544 Applications Information Table 1. RF Input Impedance and S11 (at Pin 2, No External Matching, LO Input Driven at 5GHz) S11 FREQUENCY (GHz) INPUT IMPEDANCE MAG ANGLE 4.0 85.8 + j54.1 0.44 34.8 4.2 89.2 + j45.6 0.41 31.2 4.4 90.9 + j41.3 0.40 29 4.6 95.9 + j33.6 0.38 23.2 4.8 91.4 + j17.1 0.31 15.6 5.0 72.9 + j10.7 0.21 20.1 5.2 66.7 + j24.1 0.25 43.6 5.4 70.8 + j29.1 0.29 40.9 5.6 73.1 + j26.2 0.28 36.6 5.8 69.2 + j23.9 0.25 39.9 6.0 67.3 + j25.7 0.26 43.7 low), the internal bias circuit provides a regulated 4mA current to the amplifier’s bias input, which in turn causes the amplifiers to draw approximately 90mA of DC current. This 4mA reference current is also connected to LOBIAS (Pin 6) to allow modification of the amplifier’s DC bias current for special applications. The recommended application circuits require no LO amplifier bias modification, so this pin should be left open-circuited. The nominal LO input level is +2dBm although the limiting amplifiers will deliver excellent performance over a ±3dB input power range. LO input power greater than +5dBm may be used with slightly degraded performance. The LO input impedance and input reflection coefficient, versus frequency, is shown in Table 2. Table 2. LO Input Impedance vs Frequency (at Pin 10, No External Matching) LO Input S11 FREQUENCY (GHz) INPUT IMPEDANCE MAG ANGLE 4.0 22.7 + j14.7 0.42 140.2 4.2 24.4 + j18.6 0.41 129.9 4.4 28.2 + j22.5 0.39 118.1 4.6 33.2 + j25.3 0.35 106.7 4.8 39.7 + j26.4 0.30 95 The mixer’s LO input is directly connected to the primary winding of an integrated transformer. A 50Ω match is realized with a series 1.2pF capacitor (C3). Measured LO input return loss is shown in Figure 6. 5.0 47.4 + j24.3 0.24 82.1 5.2 52.2 + j16.9 0.16 73.3 The LO amplifiers are powered through VCC1 and VCC2 (Pin 5 and Pin 7). When the chip is enabled (SHDN = 5.8 6.0 The mixer’s LO input circuit, shown in Figure 5, consists of a balun transformer and a two-stage high speed limiting differential amplifier to drive the mixer core. The LTC5544’s LO amplifiers are optimized for the 4.2GHz to 5.8GHz LO frequency range. LO frequencies above or below this frequency range may be used with degraded performance. 5.4 52 + j9.4 0.09 72.7 5.6 49.9 + j3.8 0.04 88.8 47.7 – j1 0.03 –156.5 44.2 – j6.2 0.09 –129.4 LO BUFFER TO MIXER LO 10 4mA BIAS LOBIAS 6 5 VCC1 7 C3 LOIN LO PORT RETURN LOSS (dB) 0 LTC5544 5 10 15 20 25 30 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 LO FREQUENCY (GHz) 5544 F06 VCC2 5544 F05 Figure 5. LO Input Schematic Figure 6. LO Input Return Loss 5544f 11 LTC5544 Applications Information IF Output The IF amplifier, shown in Figure 7, has differential open-collector outputs (IF+ and IF –), a DC ground return pin (IFGND), and a pin for modifying the internal bias (IFBIAS). The IF outputs must be biased at the supply voltage (VCCIF), which is applied through matching inductors L1 and L2. Alternatively, the IF outputs can be biased through the center tap of a transformer. The common node of L1 and L2 can be connected to the center tap of the transformer. Each IF output pin draws approximately 49mA of DC supply current (98mA total). IFGND (Pin 13) must be grounded or the amplifier will not draw DC current. For the highest conversion gain, high-Q wire-wound chip inductors are recommended for L1 and L2, especially when using VCCIF = 3.3V. Low cost multilayer chip inductors may be substituted, with a slight degradation in performance. Grounding through inductor L3 may improve LO-IF and RF-IF leakage performance in some applications, but is otherwise not necessary. High DC resistance in L3 will reduce the IF amplifier supply current, which will degrade RF performance. T1 IFOUT R1 (OPTION TO REDUCE DC POWER) LTC5544 4:1 C10 L1 L2 VCCIF C8 16 15 IF+ IFBIAS VCC 4mA 98mA 14 IF – L3 (OR SHORT) 13 IFGND IF AMP transformation. It is also possible to eliminate the IF transformer and drive differential filters or amplifiers directly. The IF output impedance can be modeled as 332Ω in parallel with 1.7pF at IF frequencies. An equivalent smallsignal model is shown in Figure 8. Frequency-dependent differential IF 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. LTC5544 15 IF + 14 RIF IF – CIF 5544 F08 Figure 8. IF Output Small-Signal Model Table 3. IF Output Impedance vs Frequency FREQUENCY (MHz) DIFFERENTIAL OUTPUT IMPEDANCE (RIF || XIF (CIF)) 90 351 || –j707 (2.5pF) 140 341 || –j494 (2.3pF) 190 334 || –j441 (1.9pF) 240 332 || –j390 (1.7pF) 300 325 || –j312 (1.7pF) 380 318 || –j246 (1.7pF) 456 304 || –j205 (1.7pF) Transformer-Based Bandpass IF Matching BIAS 5544 F07 Figure 7. IF Amplifier Schematic with Transformer-Based Bandpass Match For optimum single-ended performance, the differential IF outputs must be combined through an external IF transformer or discrete IF balun circuit. The evaluation board (see Figures 1 and 2) uses a 4:1 ratio IF transformer for impedance transformation and differential to single-ended The IF output can be matched for IF frequencies as low as 40MHz, or as high as 500MHz, using the bandpass IF matching shown in Figures 1 and 7. L1 and L2 resonate with the internal IF output capacitance at the desired IF frequency. The value of L1, L2 is calculated as follows: L1, L2 = 1/[(2 π fIF)2 • 2 • CIF] where CIF is the internal IF capacitance (listed in Table 3). Values of L1 and L2 are tabulated in Figure 1 for various IF frequencies 5544f 12 LTC5544 Applications Information Discrete IF Balun Matching For many applications, it is possible to replace the IF transformer with the discrete IF balun shown in Figure 9. The values of L5, L6, C13 and C14 are calculated to realize a 180° phase shift at the desired IF frequency and provide a 50Ω single-ended output, using the following equations. Inductor L7 is used to cancel the internal capacitance CIF and supplies bias voltage to the IF pin. C15 is a DC blocking capacitor. L5, L6 = RIF •ROUT C13, C14 = ωIF Table 4. Performance Comparison with VCCIF = 3.3V and 5V (RF = 5250MHz, Low Side LO, IF = 240MHz) VCCIF (V) ICCIF (mA) GC (dB) P1dB (dBm) IIP3 (dBm) NF (dB) 3.3 98 7.4 11.4 25.9 11.3 5.0 101 7.4 14.6 26.5 11.4 L5 R1 (OPTION TO REDUCE DC POWER) C13 16 IFBIAS LTC5544 VCCIF IFOUT C15 L6 C14 L3 98mA (OR SHORT) L7 15 IF+ 14 IF – 13 IFGND 1 ωIF • RIF •ROUT VCC |X | L7 = IF ωIF 5544 F09 Figure 9. IF Amplifier Schematic with Discrete IF Balun IIP3 The IF amplifier delivers excellent performance with VCCIF = 3.3V, which allows the VCC and VCCIF supplies to be common. With VCCIF increased to 5V, the RF input P1dB increases by more than 3dB, at the expense of higher power consumption. Mixer performance at 5250MHz is shown in Table 4 with VCCIF = 3.3V and 5V. 11 24 9 22 GC IF = 456MHz LOW SIDE LO TC4-1W-17LN+ BALUN DISCRETE BALUN 7 5 3 18 4.5 4.7 4.9 5.1 5.3 5.5 5.7 5.9 6.1 6.3 RF FREQUENCY (GHz) 5544 F10 Figure 10. Conversion Gain and IIP3 vs RF Frequency 0 IF PORT RETURN LOSS (dB) IF Amplifier Bias 26 20 L5, L6 = 36nH, L7 = 82nH and C13, C14 = 3.3pF Measured IF output return losses for transformer-based bandpass IF matching and discrete balun IF matching (456MHz IF frequency) are plotted in Figure 11. A discrete balun has less insertion loss than a balun transformer, but the IF bandwidth of a discrete balun is less than that of a transformer. 13 28 GC (dB) The typical performances of the LTC5544 using a discrete IF balun matching and a transformer-based IF matching are shown in Figure 10. With an IF frequency of 456MHz, the actual components values for the discrete balun are: BIAS IIP3 (dBm) These equations give a good starting point, but it is usually necessary to adjust the component values after building and testing the circuit. The final solution can be achieved with less iteration by considering the parasitics of L7 in the previous calculation. IF AMP 4mA 5 L1, L2 = 150 nH L1, L2 = 82nH L1, L2 = 39nH DISCRETE BALUN 456MHz 10 15 20 25 30 100 150 200 250 300 350 400 450 500 550 600 IF FREQUENCY (MHz) 5544 F11 Figure 11. IF Output Return Loss 5544f 13 LTC5544 Applications Information The IFBIAS pin (Pin 16) is available for reducing the DC current consumption of the IF amplifier, at the expense of reduced performance. This pin should be left open-circuited for optimum performance. The internal bias circuit produces a 4mA reference for the IF amplifier, which causes the amplifier to draw approximately 98mA. If resistor R1 is connected to Pin 16 as shown in Figure 6, a portion of the reference current can be shunted to ground, resulting in reduced IF amplifier current. For example, R1 = 1kΩ will shunt away 1.5mA from Pin 16 and the IF amplifier current will be reduced by 40% to approximately 59mA. The nominal, open-circuit DC voltage at Pin 16 is 2.1V. Table 5 lists RF performance at 5250MHz versus IF amplifier current. Table 5. Mixer Performance with Reduced IF Amplifier Current (RF = 5250MHz, Low Side LO, IF = 240MHz, VCC = VCCIF = 3.3V) R1 (kΩ) ICCIF (mA) GC (dB) IIP3 (dBm) P1dB (dBm) NF (dB) OPEN 98 7.4 25.9 11.4 11.3 4.7 89 7.2 25.7 11.5 11.4 2.2 77 6.9 25.2 11.6 11.5 1.0 59 6.3 23.8 11.3 11.6 (RF = 5250MHz, High Side LO, IF = 240MHz, VCC = VCCIF = 3.3V) LTC5544 VCC1 5 SHDN 500Ω 4 5544 F12 Figure 12. Shutdown Input Circuit Temperature Diode The LTC5544 provides an on-chip diode at Pin 12 (TEMP) for chip temperature measurement. Pin 12 is connected to the anode of an internal ESD diode with its cathode connected to internal ground. The chip temperature can be measured by injecting a constant DC current into Pin 12 and measuring its DC voltage. The voltage vs temperature coefficient of the diode is about –1.73mV/°C with 10µA current injected into the TEMP pin. Figure 13 shows a typical temperature-voltage behavior when 10µA and 80µA currents are injected into Pin 12. ICCIF (mA) GC (dB) IIP3 (dBm) P1dB (dBm) NF (dB) 900 OPEN 98 7.3 24.0 11.4 11.7 850 4.7 89 7.0 23.8 11.4 11.9 800 2.2 77 6.6 23.5 11.4 12.2 1.0 59 5.8 22.6 11.3 12.4 Shutdown Interface Figure 12 shows a simplified schematic of the SHDN pin interface. To disable the chip, the SHDN voltage must be higher than 3.0V. If the shutdown function is not required, the SHDN pin should be connected directly to GND. The voltage at the SHDN pin should never exceed the power supply voltage (VCC) by more than 0.3V. If this should occur, the supply current could be sourced through the ESD diode, potentially damaging the IC. The SHDN pin must be pulled high or low. If left floating, then the on/off state of the IC will be indeterminate. If a three-state condition can exist at the SHDN pin, then a pull-up or pull-down resistor must be used. TEMP DIODE VOLTAGE (mV) R1 (kΩ) 80µA 750 700 650 10µA 600 550 500 450 400 –40 40 80 –20 20 60 0 JUNCTION TEMPERATURE (°C) 100 5544 F13 Figure 13. TEMP Diode Voltage vs Junction Temperature (TJ) Supply Voltage Ramping Fast ramping of the supply voltage can cause a current glitch in the internal ESD protection circuits. Depending on the supply inductance, this could result in a supply voltage transient that exceeds the maximum rating. A supply voltage ramp time of greater than 1ms is recommended. 5544f 14 LTC5544 Package Description Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. 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 0.35 × 45° CHAMFER 16 0.55 ± 0.20 PIN 1 TOP MARK (NOTE 6) 1 2.15 ±0.10 (4-SIDES) 2 (UF16) QFN 10-04 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 5544f 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 LTC5544 Typical Application 900MHz IF Output Matching IFOUT 50Ω Conversion Gain, IIP3 and NF vs RF Frequency TM4-1 (SYNERGY) 3.3pF IF+ IF – IFGND TEMP IF 0.6pF RFIN 50Ω 1.2pF RF LO LO LOIN 50Ω 2.2nH SHDN SHDN IIP3 (dBm), SSB NF (dB) 22pF 22nH 22 5 GC 18 4 16 3 14 2 SSB NF 12 5.1 5.3 5.5 5.7 5.9 RF FREQUENCY (GHz) 1 6.1 0 6.3 5544 TA02b VCC2 VCC1 VCC 3.3V 7 6 20 10 4.9 BIAS 8 IF = 900MHz LOW SIDE LO 24 GC (dB) 1µF 9 26 1000pF 1000pF 22nH IIP3 28 1000pF VCCIF 3.3V 10 30 5544 TA02a 1µF 22pF Related Parts PART NUMBER DESCRIPTION COMMENTS Infrastructure LTC554X 600MHz to 6GHz 3.3V Downconverting Mixers 8dB Gain, 26dBm IIP3, 10dB NF, 3.3V/200mA Supply LT 5527 400MHz to 3.7GHz, 5V Downconverting Mixer 2.3dB Gain, 23.5dBm IIP3 and 12.5dB NF at 1900MHz, 5V/78mA Supply LT5557 400MHz to 3.8GHz, 3.3V Downconverting Mixer 2.9dB Gain, 24.7dBm IIP3 and 11.7dB NF at 1950MHz, 3.3V/82mA Supply ® LTC559x 600MHz to 4.5GHz Dual Downconverting Mixer Family 8.5dB Gain, 26.5dBm IIP3, 9.9dB NF, 3.3V/380mA Supply LTC5569 300MHz to 4GHz 3.3V Dual Downconverting Mixer 2dB Gain, 26.8dBm IIP3 and 11.7dB NF at 1950MHz, 3.3V/180mA Supply LTC6400-X 300MHz Low Distortion IF Amp/ADC Driver Fixed Gain of 8dB, 14dB, 20dB and 26dB; >36dBm OIP3 at 300MHz, Differential I/O LTC6416 2GHz 16-Bit ADC Buffer 40dBm OIP3 to 300MHz, Programmable Fast Recovery Output Clamping LTC6412 31dB Linear Analog VGA 35dBm OIP3 at 240MHz, Continuous Variable Gain Range –14dB to 17dB LT5554 Ultralow Distort IF Digital VGA 48dBm OIP3 at 200MHz, 2dB to 18dB Gain Range, 0.125dB Gain Steps LT5578 400MHz to 2.7GHz Upconverting Mixer 27dBm OIP3 at 900MHz, 24.2dBm at 1.95GHz, Integrated RF Transformer LT5579 1.5GHz to 3.8GHz Upconverting Mixer 27.3dBm OIP3 at 2.14GHz, NF = 9.9dB, 3.3V Supply, Single-Ended LO and RF Ports LTC5588-1 200MHz to 6GHz I/Q Modulator 31dBm OIP3 at 2.14GHz, –160.6dBm/Hz Noise Floor RF Power Detectors LTC5587 6GHz RMS Detector with 12-Bit ADC 40dB Dynamic Range, ±1dB Accuracy Over Temperature, 3mA Current, 500ksps LT5581 6GHz Low Power RMS Detector 40dB Dynamic Range, ±1dB Accuracy Over Temperature, 1.5mA Supply Current LTC5582 40MHz to 10GHz RMS Detector 57dB Dynamic Range, ±0.5dB Accuracy Over Temperature, ±0.2dB Linearity Error LTC5583 Dual 6GHz RMS Power Detector Up to 60dB Dynamic Range, ±0.5dB Accuracy Over Temperature, >50dB Isolation LTC2208 16-Bit, 130Msps ADC 78dBFS Noise Floor, >83dB SFDR at 250MHz LTC2285 Dual 14-Bit, 125Msps Low Power ADC 72.4dB SNR, 88dB SFDR, 790mW Power Consumption LTC2268-14 Dual 14-Bit, 125Msps Serial Output ADC 73.1dB SNR, 88dB SFDR, 299mW Power Consumption ADCs 5544f 16 Linear Technology Corporation LT 0312 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2012