LTC6410-6 Low Distortion, Low Noise Differential IF Amplifier with Configurable Input Impedance DESCRIPTION FEATURES n n n n n n n n n n n The LTC®6410-6 is a low distortion, low noise differential IF amplifier with configurable input impedance designed for use in applications from DC to 1.4GHz. The LTC6410-6 has 6dB of voltage gain. The LTC6410-6 is an excellent choice for interfacing active mixers to SAW filters. It features an active input termination that allows a customized input impedance for an optimum interface to differential active mixers. This feature provides additional power gain because of the impedance conversion and improved noise performance when compared to traditional 50Ω interface circuits. The LTC6410-6 drives a differential 50Ω load directly with low distortion, which is suitable for driving SAW filters and other 50Ω signal chain blocks. 1.4GHz –3dB Bandwidth Fixed Voltage Gain of 6dB (50Ω System) Configurable Input Impedance Allows: Simple Interface to Active Mixers Improved Noise Performance Wide 2.8V to 5.25V Supply Range Low Distortion: 36dBm OIP3 (70MHz) 33dBm OIP3 (140MHz) 31dBm OIP3 (300MHz) Low Noise: 11dB NF (50Ω ZIN) 8dB NF (200Ω ZIN) Differential Inputs and Outputs Self-Biasing Inputs/Outputs Shutdown Mode Minimal Support Circuitry Required 16-Lead 3mm × 3mm × 0.8mm QFN Package The LTC6410-6 operates on 3V or 5V supplies. It comes in a compact 16-lead 3mm × 3mm QFN package and operates over a –40°C to 85°C temperature range. L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. APPLICATIONS n n n n Post-Mixer Gain Block SAW Filter Interface/Buffering Differential IF Signal Chain Gain Block Differential Line Driver/Receiver TYPICAL APPLICATION 2-Tone Spectrum Analyzer Plot Post Mixer Gain Block (140MHz IF) 5V 0 5V –20 82nH 24nH 0.1μF V+ –IN 12pF 680pF –TERM SHDN –OUT 18pF LTC6410-6 +OUT 24nH +IN 12pF 1760MHz LO LT5527 MIXER 18pF +TERM VBIAS V– 64106 TA01a 0.1μF SYSTEM OIP3 = 29dBm AT 1900MHz SYSTEM NF = 15dB AT 1900MHz OUTPUT POWER (dBm) 82nH –10 –30 –40 –50 –60 –70 –80 –90 –100 130 132 134 136 138 140 142 144 146 148 150 FREQUENCY (MHz) 64106 TA01b 64106fa 1 LTC6410-6 ABSOLUTE MAXIMUM RATINGS PIN CONFIGURATION Total Supply Voltage (V+ to V–) ................................5.5V Amplifier Input Current (DC) (+IN, –IN, +TERM, –TERM) .............................±10mA Amplifier Input Power (AC) (+IN, –IN, +TERM, –TERM) .............................18dBm Input Current (VBIAS, SHDN) ................................±10mA Output Current (+OUT, –OUT) ..............................±50mA Operating Temperature Range (Note 2).... –40°C to 85°C Specified Temperature Range (Note 3) .... –40°C to 85°C Storage Temperature Range................... –65°C to 150°C Junction Temperature .......................................... 150°C Lead Temperature (Soldering, 10 sec) .................. 300°C –IN +IN +TERM TOP VIEW –TERM (Note 1) 16 15 14 13 V– 1 12 V– VBIAS 2 10 V+ 9 V– 7 8 V+ 6 –OUT 5 +OUT 4 V+ V– 11 SHDN 17 V+ 3 UD PACKAGE 16-LEAD (3mm × 3mm) PLASTIC QFN TJMAX = 150°C, θJA = 68°C/W, θJC = 4.2°C/W EXPOSED PAD (PIN 17) IS V–, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE (Notes 2, 3) LTC6410CUD-6#PBF LTC6410CUD-6#TRPBF LDBG 16-Lead (3mm × 3mm) Plastic QFN –40°C to 85°C LTC6410IUD-6#PBF LTC6410IUD-6#TRPBF LDBG 16-Lead (3mm × 3mm) Plastic QFN –40°C to 85°C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. 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/ 3V DC ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. V+ = 3V, V– = 0V, SHDN = 2V, +IN is shorted to +TERM, –IN is shorted to –TERM, VBIAS = 1.5V, +IN = –IN = 1.5V, input source resistance (RS) is 25Ω on each input (50Ω differential), RL = 50Ω from +OUT to –OUT, unless otherwise noted. VBIAS is defined as the voltage on the VBIAS pin. VOUTCM is defined as (+OUT + –OUT)/2. VINCM is defined as (+IN + –IN)/2. VINDIFF is defined as (+IN – –IN). VOUTDIFF is defined as (+OUT – –OUT). See DC test circuit schematic. SYMBOL PARAMETER CONDITIONS GDIFF Differential Gain (Low Frequency S21) VINDIFF = ±0.2V TC GDIFF Differential Gain Temperature Coefficient VSWINGDIFF Differential Output Voltage Swing VSWINGMIN Output Swing Low VSWINGMAX Output Swing High IOUT Output Current Drive VOS Input Offset Voltage l MIN TYP MAX 5.0 4.7 6.0 6.7 7.0 l VOUTDIFF, VINDIFF = ±2V Single-Ended +OUT, –OUT, VINDIFF = ±2V Single-Ended +OUT, –OUT, VINDIFF = ±2V Short +OUT to –OUT, VINDIFF = ±2V (Note 4) l 2.2 2.0 UNITS dB dB 0.003 dB/°C 2.8 VP-P VP-P 0.7 l 0.9 1.0 V V 1.9 1.8 2.1 l V V ±38 ±36 ±42 l mA mA –2.0 –3.0 0.4 l 2.0 3.0 mV mV 64106fa 2 LTC6410-6 3V DC ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. V+ = 3V, V– = 0V, SHDN = 2V, +IN is shorted to +TERM, –IN is shorted to –TERM, VBIAS = 1.5V, +IN = –IN = 1.5V, input source resistance (RS) is 25Ω on each input (50Ω differential), RL = 50Ω from +OUT to –OUT, unless otherwise noted. VBIAS is defined as the voltage on the VBIAS pin. VOUTCM is defined as (+OUT + –OUT)/2. VINCM is defined as (+IN + –IN)/2. VINDIFF is defined as (+IN – –IN). VOUTDIFF is defined as (+OUT – –OUT). See DC test circuit schematic. SYMBOL PARAMETER CONDITIONS MIN TC VOS Input Offset Voltage Drift VOSINCM Common Mode Offset Voltage AV Internal Voltage Gain IVRMIN Input Common Mode Voltage Range, (Min) l IVRMAX Input Common Mode Voltage Range, (Max) l 2.0 RINDIFF Differential Input Resistance l 40 30 XINDIFF Differential Input Reactance RINCM Input Common Mode Resistance CMRR Common Mode Rejection Ratio VBIAS = 1.5V, +IN = –IN = 1V to 2V, (ΔVOUTDIFF /Gain) RODIFF Differential Output Resistance VOUTDIFF = ±100mV (Note 4) XOUTDIFF Differential Output Reactance ROUTCM Common Mode Output Resistance l VOUTCM – VINCM l TYP MAX –0.3 –40 –50 13 μV/°C 40 50 2.7 VINDIFF = ±100mV (Note 4) mV mV V/V 1.0 f = 100MHz UNITS V V 58 80 100 1 Ω Ω pF 1000 Ω l 45 60 dB 17 13 22 l f = 100MHz 38 47 Ω Ω 10 nH 7 Ω Bias Voltage Control (VBIAS Pin) GCM Common Mode Gain VBIAS = 1.2V to 1.8V (+IN and –IN floating), ΔVOUTCM /(0.6V) VOCMMIN Output Common Mode Voltage Adjustment Range, (Min) l VOCMMAX Output Common Mode Voltage Adjustment Range, (Max) l 1.8 2.0 VOSCM Output Common Mode Offset Voltage VOUTCM – VBIAS –200 –400 100 l 300 400 mV mV RVOCM VBIAS Input Resistance l 2.4 2.0 3.0 3.6 4.0 kΩ kΩ CVBIAS VBIAS Input Capacitance l 0.7 0.6 0.86 1.0 1.0 V/V V/V 1.0 1.2 V V 3 pF 1.0 V SHDN Pin VIL SHDN Input Low Voltage l VIH SHDN Input High Voltage l IIL SHDN Input Low Current SHDN = 0.8V l IIH SHDN Input High Current SHDN = 2V 0.8 1.8 2 V –200 –85 0 μA l –150 –30 0 μA l 2.8 5.25 V 104 130 140 mA mA 3 5 mA Power Supply VS Operating Range IS Supply Current ISSHDN Supply Current in Shutdown SHDN = 0.8V l Power Supply Rejection Ratio V+ = 2.8V to 5.25V, VBIAS = +IN = –IN = V+/2 l PSRR l 73 100 dB 64106fa 3 LTC6410-6 5V DC ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. V+ = 5V, V– = 0V, SHDN = 3V, +IN is shorted to +TERM, –IN is shorted to –TERM, VINCM = VBIAS = 2.5V, +IN = –IN = 2.5V, input source resistance (RS) is 25Ω on each input (50Ω differential), RL = 50Ω from +OUT to –OUT, unless otherwise noted. VBIAS is defined as the voltage on theVBIAS pin. VOUTCM is defined as (+OUT + –OUT)/2. VINCM is defined as (+IN + –IN)/2. VINDIFF is defined as (+IN – –IN). VOUTDIFF is defined as (+OUT – –OUT). See DC test circuit schematic. SYMBOL PARAMETER CONDITIONS MIN TYP MAX GDIFF Differential Gain (Low Frequency S21) VIN = ±0.2V l 5 4.7 6.1 6.7 7.0 VSWINGDIFF Differential Output Voltage Swing VOUTDIFF, VIN = ±4V 4.1 3.5 4.8 l VSWINGMIN Output Swing Low VSWINGMAX Output Swing High IS Supply Current Single-Ended +OUT, –OUT, VIN = ±4V Single-Ended +OUT, –OUT, VIN = ±4V 1.1 l l 3.2 3.0 dB dB VP-P VP-P 1.4 1.6 V V 3.5 125 l UNITS V V 150 160 mA mA SHDN Pin VIL SHDN Input Low Voltage l l 1.8 2.0 V VIH SHDN Input High Voltage 2.8 3 V IIL SHDN Input Low Current SHDN = 1.8V l –300 –110 0 μA IIH SHDN Input High Current SHDN = 3V l –200 –60 0 μA AC ELECTRICAL CHARACTERISTICS + The l denotes the specifications which apply over the full operating – temperature range, otherwise specifications are at TA = 25°C. V = 3V, V = 0V, SHDN = 2V, +IN is shorted to +TERM, –IN is shorted to –TERM, VINCM = VBIAS = 1.5V, input source resistance (RS) is 25Ω on each input (50Ω differential), RL = 50Ω from +OUT to –OUT, +IN and –IN are AC-coupled, unless otherwise noted. VBIAS is defined as the voltage on theVBIAS pin. VOUTCM is defined as (+OUT + –OUT)/2. VINCM is defined as (+IN + –IN)/2. VINDIFF is defined as (+IN – –IN). VOUTDIFF is defined as (+OUT – –OUT). SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS –3dBBW –3dB Bandwidth VINDIFF = –10dBm 1 1.4 GHz 0.1dBBW Bandwidth for 0.1dB Flatness 0.5dBBW Bandwidth for 0.5dB Flatness VINDIFF = –10dBm 150 MHz VINDIFF = –10dBm 300 MHz SR Slew Rate 1.5 V/ns ts 1% Settling Time 1% Settling for a 1VP-P VOUTDIFF Step 3 ns tON Turn-On Time SHDN = 0V to 3V, +OUT and –OUT Within 10% of Final Values 30 ns tOFF Turn-Off Time SHDN = 3V to 0V, +OUT and –OUT Within 10% of Final Values 30 ns 0.2VP-P at VBIAS, Measured VOUTCM 1 GHz 100 V/μs Common Mode Voltage Control (VBIAS Pin) –3dBBWCM Common Mode Small-Signal –3dB Bandwidth SRCM Common Mode Slew Rate Noise/Harmonic Performance Input/Output Characteristics 10MHz Signal HD2 Second Harmonic Distortion VOUTDIFF = 0dBm –85 dBc HD3 Third Harmonic Distortion VOUTDIFF = 0dBm –71 dBc 64106fa 4 LTC6410-6 AC ELECTRICAL CHARACTERISTICS + The l denotes the specifications which apply over the full operating – temperature range, otherwise specifications are at TA = 25°C. V = 3V, V = 0V, SHDN = 2V, +IN is shorted to +TERM, –IN is shorted to –TERM, VINCM = VBIAS = 1.5V, input source resistance (RS) is 25Ω on each input (50Ω differential), RL = 50Ω from +OUT to –OUT, +IN and –IN are AC-coupled, unless otherwise noted. VBIAS is defined as the voltage on theVBIAS pin. VOUTCM is defined as (+OUT + –OUT)/2. VINCM is defined as (+IN + –IN)/2. VINDIFF is defined as (+IN – –IN). VOUTDIFF is defined as (+OUT – –OUT). SYMBOL PARAMETER CONDITIONS IM3 Third Order Intermodulated Distortion F1 = 9.5MHz, F2 = 10.5MHz, VOUTDIFF = 0dBm/Tone –72 dBc F1 = 9.5MHz, F2 = 10.5MHz, VOUTDIFF = –5dBm/Tone –81 dBc F1 = 9.5MHz, F2 = 10.5MHz, VOUTDIFF = 0dBm/Tone, VCC = 5V, VBIAS = 2.5V, SHDN = 3V –66 dBc F1 = 9.5MHz, F2 = 10.5MHz, VOUTDIFF = 0dBm/Tone 36 dBm F1 = 9.5MHz, F2 = 10.5MHz, VOUTDIFF = –5dBm/Tone 36 dBm F1 = 9.5MHz, F2 = 10.5MHz, VOUTDIFF = 0dBm/Tone, VCC = 5V, VBIAS = 2.5V, SHDN = 3V 33 dBm 12.8 dBm OIP3 Output Third-Order Intercept MIN TYP MAX UNITS P1dB Output 1dB Compression Point NF Noise Figure ZIN = 50Ω (Note 5) ZIN = 200Ω 11 8 dB dB HD2 Second Harmonic Distortion VOUTDIFF = 0dBm –85 dBc HD3 Third Harmonic Distortion VOUTDIFF = 0dBm –69 dBc IM3 Third Order Intermodulated Distortion F1 = 69.5MHz, F2 = 70.5MHz, VOUTDIFF = 0dBm/Tone –72 dBc 70MHz Signal OIP3 Output Third-Order Intercept P1dB Output 1dB Compression Point NF Noise Figure F1 = 69.5MHz, F2 = 70.5MHz, VOUTDIFF = –5dBm/Tone –79 dBc F1 = 69.5MHz, F2 = 70.5MHz, VOUTDIFF = 0dBm/Tone, VCC = 5V, VBIAS = 2.5V, SHDN = 3V –72 dBc F1 = 69.5MHz, F2 = 70.5MHz, VOUTDIFF = 0dBm/Tone 36 dBm F1 = 69.5MHz, F2 = 70.5MHz, VOUTDIFF = –5dBm/Tone 35 dBm F1 = 69.5MHz, F2 = 70.5MHz, VOUTDIFF = 0dBm/Tone, VCC = 5V, VBIAS = 2.5V, SHDN = 3V 36 dBm 12.8 dBm ZIN = 50Ω (Note 5) ZIN = 200Ω 11 8 dB dB 140MHz Signal HD2 Second Harmonic Distortion VOUTDIFF = 0dBm –80 dBc HD3 Third Harmonic Distortion VOUTDIFF = 0dBm –62 dBc IM3 Third Order Intermodulated Distortion F1 = 139.5MHz, F2 = 140.5MHz, VOUTDIFF = 0dBm/Tone –62 dBc F1 = 139.5MHz, F2 = 140.5MHz, VOUTDIFF = –5dBm/Tone –70 dBc F1 = 139.5MHz, F2 = 140.5MHz, VOUTDIFF = 0dBm/Tone, VCC = 5V, VBIAS = 2.5V, SHDN = 3V –66 dBc F1 = 130MHz, F2 = 150MHz, VOUTDIFF = 0dBm/Tone, VCC = 5V, VBIAS = 2.5V, SHDN = 3V –66 F1 = 139.5MHz, F2 = 140.5MHz, VOUTDIFF = 0dBm/Tone 31 OIP3 Output Third-Order Intercept Output 1dB Compression Point dBc dBm F1 = 139.5MHz, F2 = 140.5MHz, VOUTDIFF = –5dBm/Tone 30 dBm F1 = 139.5MHz, F2 = 140.5MHz, VOUTDIFF = 0dBm/Tone, VCC = 5V, VBIAS = 2.5V, SHDN = 3V 33 dBm 33 dBm 12.8 dBm F1 = 130MHz, F2 = 150MHz, VOUTDIFF = 0dBm/Tone, VCC = 5V, VBIAS = 2.5V, SHDN = 3V P1dB –56 28 64106fa 5 LTC6410-6 AC ELECTRICAL CHARACTERISTICS + The l denotes the specifications which apply over the full operating – temperature range, otherwise specifications are at TA = 25°C. V = 3V, V = 0V, SHDN = 2V, +IN is shorted to +TERM, –IN is shorted to –TERM, VINCM = VBIAS = 1.5V, input source resistance (RS) is 25Ω on each input (50Ω differential), RL = 50Ω from +OUT to –OUT, +IN and –IN are AC-coupled, unless otherwise noted. VBIAS is defined as the voltage on theVBIAS pin. VOUTCM is defined as (+OUT + –OUT)/2. VINCM is defined as (+IN + –IN)/2. VINDIFF is defined as (+IN – –IN). VOUTDIFF is defined as (+OUT – –OUT). SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS NF Noise Figure ZIN = 50Ω (Note 5) ZIN = 200Ω 11 7 dB dB 240MHz Signal HD2 Second Harmonic Distortion VOUTDIFF = 0dBm –66 dBc HD3 Third Harmonic Distortion VOUTDIFF = 0dBm –52 dBc IM3 Third Order Intermodulated Distortion F1 = 239.5MHz, F2 = 240.5MHz, VOUTDIFF = 0dBm/Tone –54 dBc F1 = 239.5MHz, F2 = 240.5MHz, VOUTDIFF = –5dBm/Tone –63 dBc F1 = 239.5MHz, F2 = 240.5MHz, VOUTDIFF = 0dBm/Tone, VCC = 5V, VBIAS = 2.5V, SHDN = 3V –64 dBc OIP3 Output Third-Order Intercept P1dB Output 1dB Compression Point NF Noise Figure F1 = 239.5MHz, F2 = 240.5MHz, VOUTDIFF = 0dBm/Tone 27 dBm F1 = 239.5MHz, F2 = 240.5MHz, VOUTDIFF = –5dBm/Tone 27 dBm F1 = 239.5MHz, F2 = 240.5MHz, VOUTDIFF = 0dBm/Tone, VCC = 5V, VBIAS = 2.5V, SHDN = 3V 32 dBm 12.8 dBm ZIN = 50Ω (Note 5) ZIN = 200Ω 11 8 dB dB VOUTDIFF = 0dBm –57 dBc 380MHz Signal HD2 Second Harmonic Distortion HD3 Third Harmonic Distortion VOUTDIFF = 0dBm –45 dBc IM3 Third Order Intermodulated Distortion F1 = 379.5MHz, F2 = 380.5MHz, VOUTDIFF = 0dBm/Tone –51 dBc F1 = 379.5MHz, F2 = 380.5MHz, VOUTDIFF = –5dBm/Tone –64 dBc F1 = 379.5MHz, F2 = 380.5MHz, VOUTDIFF = 0dBm/Tone, VCC = 5V, VBIAS = 2.5V, SHDN = 3V –60 dBc F1 = 379.5MHz, F2 = 380.5MHz, VOUTDIFF = 0dBm/Tone 26 dBm F1 = 379.5MHz, F2 = 380.5MHz, VOUTDIFF = –5dBm/Tone 27 dBm F1 = 379.5MHz, F2 = 380.5MHz, VOUTDIFF = 0dBm/Tone, VCC = 5V, VBIAS = 2.5V, SHDN = 3V 30 dBm 10.8 dBm OIP3 Output Third-Order Intercept P1dB Output 1dB Compression Point NF Noise Figure ZIN = 50Ω (Note 5) ZIN = 200Ω 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 LTC6410C-6/LTC6410I-6 is guaranteed functional over the operating temperature range of –40°C to 85°C. Note 3: The LTC6410C-6 is guaranteed to meet specified performance from 0°C to 70°C. It is designed, characterized and expected to meet specified performance from –40°C and 85°C but is not tested or QA 12 8 dB dB sampled at these temperatures. The LT6410I-6 is guaranteed to meet specified performance from –40°C to 85°C. Note 4: This parameter is pulse tested. Note 5: en can be calculated from ZIN = 50Ω NF with the formula: NF en = (10 10 – 1)4kT50 where k = Boltzmann’s constant and T = absolute temperature 64106fa 6 LTC6410-6 TYPICAL PERFORMANCE CHARACTERISTICS 40 38 V+ = 3V V– = 0V ZIN = 50Ω RL = 50Ω VBIAS = 1.5V POUT = 0dBm 36 34 34 32 30 28 32 30 28 26 26 –20 –30 –40 –90 –100 0 50 100 150 200 250 300 350 400 FREQUENCY (MHz) –30 Third Order Intermodulation Distortion vs Temperature 240MHz –40 –50 140MHz –60 –70 10MHz –80 –90 30MHz –55.0 –57.5 –60.0 V+ = 3V V– = 0V ZIN = 50Ω RL = 50Ω FREQ = 139.5MHz, 140.5MHz POUT = 0dBm VBIAS = 1.5V –62.5 –65.0 70MHz –67.5 5 0 –2.5 2.5 OUTPUT POWER (dBm) –5 –70.0 –50 –25 0 30 28 13 12 26 100 150 200 250 300 350 400 FREQUENCY (MHz) 64106 G07 0 50 100 150 200 250 300 350 400 FREQUENCY (MHz) 64106 G06 Distortion vs Common Mode Voltage 19 40 18 35 17 30 16 15 14 13 10 25 20 15 10 12 V+ = 5V V– = 0V VBIAS = 2.5V 11 50 14 10 OIP3 (dBm) 32 P1dB COMPRESSION (dBm) 34 0 15 Output 1dB Compression vs Frequency V+ = 5V V– = 0V ZIN = 50Ω RL = 50Ω VBIAS = 2.5V POUT = 0dBm 36 16 64106 G05 Output Third Order Intercept vs Frequency 38 19 ZIN = 50Ω + 18 V = 3V V– = 0V 17 VBIAS = 1.5V 11 25 50 75 100 125 150 TEMPERATURE (°C) 64106 G04 40 Output 1dB Compression vs Frequency –52.5 380MHz 5 0 –2.5 2.5 OUTPUT POWER (dBm) 64106 G03 P1dB COMPRESSION (dBm) –20 70MHz 30MHz –5 –50.0 V+ = 3V V– = 0V ZIN = 200Ω RL = 50Ω VBIAS = 1.5V –10 10MHz 64106 G02 THIRD ORDER IMD (dBc) 0 140MHz –70 22 100 150 200 250 300 350 400 FREQUENCY (MHz) 380MHz –60 22 50 240MHz –50 24 0 V+ = 3V V– = 0V ZIN = 50Ω RL = 50Ω –80 64106 G01 THIRD ORDER IMD (dBc) 0 –10 24 Third Order Intermodulation Distortion vs Frequency vs Power (ZIN = 200Ω) OIP3 (dBm) Third Order Intermodulation Distortion vs Frequency vs Power V+ = 3V V– = 0V ZIN = 200Ω RL = 50Ω VBIAS = 1.5V POUT = 0dBm 36 OIP3 (dBm) 38 OIP3 (dBm) Output Third Order Intercept vs Frequency (ZIN = 200Ω) THIRD ORDER IMD (dBc) Output Third Order Intercept vs Frequency 0 50 5 100 150 200 250 300 350 400 FREQUENCY (MHz) 64106 G08 V+ = 3V V– = 0V ZIN = 50Ω RL = 50Ω FREQ = 139.5MHz, 140MHz POUT = 0dBm 0 1.2 1.3 1.4 1.6 1.5 VBIAS (V) 1.7 1.8 64106 G09 64106fa 7 LTC6410-6 TYPICAL PERFORMANCE CHARACTERISTICS Differential Input Return Loss vs Frequency (S11) 0 DIFFERENTIAL INPUT RETURN LOSS (dB) 10 8 DIFFERENTIAL GAIN (dB) 6 4 2 0 –2 –4 –6 V+ = 3V V– = 0V ZIN = 50Ω –8 –10 1 0 V+ = 3V V– = 0V ZIN = 50Ω –5 –10 –15 –20 1000 1 DIFFERENTIAL REVERSE ISOLATION (dB) –10 –15 –20 10 100 FREQUENCY (MHz) 10 100 FREQUENCY (MHz) 1 1000 1000 64106 G12 Differential Input Return Loss vs Frequency on a Smith Chart (S11) Differential Output Return Loss vs Frequency on a Smith Chart (S22) FREQ = 1MHz TO 2GHz V+ = 3V V– = 0V FREQ = 1MHz TO 2GHz V+ = 3V V– = 0V V+ = 3V V– = 0V ZIN = 50Ω –10 –5 64106 G11 Differential Reverse Isolation vs Frequency (S12) 0 V+ = 3V V– = 0V ZIN = 50Ω –25 –25 10 100 FREQUENCY (MHz) 64106 G10 –5 Differential Output Return Loss vs Frequency (S22) DIFFERENTIAL OUTPUT RETURN LOSS (dB) Differential Gain vs Frequency (S21) –15 –20 100MHz –25 1MHz –30 –35 1MHz 100MHz 1GHz 1GHz –40 –45 –50 10 100 FREQUENCY (MHz) 1 1000 64106 G14 64106 G15 64106 G13 Small-Signal Transient Large-Signal Transient 1.54 1.50 1.46 2.5 5 7.5 TIME (ns) 10 15 64106 G16 2.3 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) 1.58 1.42 0 Overdrive Recovery 1.9 1.7 1.5 1.3 1.1 0 2.5 5 7.5 TIME (ns) 10 15 64106 G17 1.9 1.5 1.1 0.7 0 5 10 15 TIME (ns) 20 25 64106 G18 64106fa 8 LTC6410-6 TYPICAL PERFORMANCE CHARACTERISTICS Noise Figure vs Frequency vs ZIN Turn-On Time 22.5 V 1.5 1.5 12.5 ZIN = 50Ω ZIN = 100Ω 10.0 ZIN = 400Ω 0 SHDN –OUT 0.5 0 SHDN 2 2 0 0 ZIN = 200Ω 2.5 0 100 FREQUENCY (MHz) 10 +OUT 1.0 0.5 7.5 5.0 +OUT –OUT 1.0 17.5 VOLTAGE (V) NOISE FIGURE (dB) 20.0 15.0 Turn-Off Time 2.0 2.0 V+ = 3V – = 0V VOLTAGE (V) 25.0 –2 1000 0 100 200 300 TIME (ns) 400 –2 500 0 300 200 TIME (ns) 100 64106 G20 400 500 64106 G21 64106 G19 Group Delay and Phase vs Frequency 2.50 10 2.25 20 2.00 30 40 CMRR vs Frequency 90 100 1.75 –45 70 1.50 –90 V+ = 3V 45 V– = 0V ZIN = 50Ω 0 PHASE V+ = 3V 90 V– = 0V Z = 50Ω 80 IN CMRR (dB) GROUP DELAY (ns) 0 PHASE (DEG) OUTPUT POWER (dBm) Spectrum Analyzer 2-Tone 60 1.25 –135 1.00 –180 0.75 –225 30 80 0.50 –270 20 90 0.25 –315 10 0 –360 10000 0 50 60 70 100 67.5 68.5 69.5 70.5 71.5 FREQUENCY (MHz) 72.5 GROUP DELAY 100 1000 FREQUENCY (MHz) 10 64106 G22 50 40 1 10 100 1000 FREQUENCY (MHz) 10000 64106 G24 64106 G23 DC TEST CIRCUIT SCHEMATIC V+ 3 V+ VBIAS 25Ω VINDIFF = +IN – –IN –IN VINCM = +IN + –IN 2 +IN 2 13 14 25Ω SHDN 15 16 11 5 V+ VBIAS 8 V+ –TERM –IN 10 V+ –OUT 7 LTC6410-6 +IN +OUT +TERM SHDN V– 1 V– 4 V– 9 –OUT RL = 50Ω V– 12 6 +OUT VOUTDIFF = +OUT – –OUT VOUTCM = +OUT + –OUT 2 64106 TC V– 64106fa 9 LTC6410-6 PIN FUNCTIONS V– (Pins 1, 4, 9, 12, 17): Negative Power Supply (Normally Tied to Ground). All 5 pins must be tied to the same voltage. V– maybe tied to a voltage other than ground as long as the voltage between V+ and V– is 2.8V to 5.5V. If the V– pins are not tied to ground, bypass each with 680pF and 0.1μF capacitors as close to the package as possible. VBIAS (Pin 2): This pin sets the input and output common mode voltage by driving the +IN and –IN through a buffer with a high output resistance of 1k. If the part is AC-coupled at the input, the VBIAS will set the VINCM and therefore the VOUTCM voltage. If the part is DC-coupled at the input, VBIAS should be left floating. Internal resistors bias VBIAS to 1.4V on a 3V supply. V+ (Pins 3, 5, 8, 10): Positive Power Supply. All 4 pins must be tied to the same voltage. Split supplies are possible as long as the voltage between V+ and V– is 2.8V to 5.5V. Bypass capacitors of 680pF and 0.1μF as close to the part as possible should be used between supplies. +OUT, –OUT (Pins 6, 7): Outputs. These pins each have internal series termination resistors forming a differential output resistance. SHDN (Pin 11): This pin is internally pulled high by a typically 30k resistor to V+. By pulling this pin low the supply current will be reduced to typically 3mA. See DC Electrical Characteristics table for the specific logic levels. –TERM (Pin 13): Negative Input Termination. When tied directly to –IN, it provides an active 50Ω differential termination when +TERM is also tied directly to +IN. –IN (Pin 14): Negative Input. This pin is normally tied to –TERM, the input termination pin. If AC-coupled, this pin will self bias by VBIAS. +IN (Pin 15): Positive Input. This pin is normally tied to +TERM, the input termination pin. If AC-coupled, this pin will self bias by VBIAS. +TERM (Pin 16): Positive Input Termination. When tied directly to +IN, it provides an active 50Ω differential termination when –TERM is also tied directly to –IN. Exposed Pad (Pin 17): V–. The Exposed Pad must be soldered to the PCB metal. BLOCK DIAGRAM CEXT (OPT) REXT (OPT) RT 110Ω –TERM –IN –IN V+ 6.4k VBIAS 1k +1 AV = 2.7V/V 0.1μF 5.7k +IN +IN +TERM REXT CEXT (OPT) (OPT) – – 1k + + RO 11Ω –OUT RO 11Ω +OUT V– RT 110Ω 64106 BD 64106fa 10 LTC6410-6 APPLICATIONS INFORMATION Introduction The LTC6410-6 is a low noise differential high speed amplifier. By default, the LTC6410-6 has 6dB voltage gain and is designed to operate with 50Ω differential input and output impedances. By changing (REXT), alternative configurations provide input resistances of up to 400Ω, with correspondingly lower noise figure and higher power gain. The Block Diagram shows the basic circuit along with key external components while Table 1 provides configuration information. If the input is AC-coupled, the VBIAS pin sets the input common mode voltage and therefore the output common mode voltage. Input Impedance LTC6410-6 has been designed with very flexible input termination circuitry. By default, with the termination pins connected directly to the inputs, the input impedance is 58Ω, see the Block Diagram. Internally, there is 110Ω between each input and the opposite output (RT). Dividing the resistor by the internal noise gain of 2.7 + 1 = 3.7, 29.5Ω input impedance is created (59Ω differential ). In parallel with the 2k common mode resistance, a total of 58Ω differential input impedance is achieved. This method of termination is used to provide lower noise figure through the use of feedback which reduces the effective noise of the termination resistor. By adding additional resistance in series with the termination pins, higher input impedances can be obtained (see Table 1). The optimum impedance for minimizing the noise figure of the LTC6410-6 is close to 400Ω. Because the amplifier is inherently a voltage amplifier, the difference between the impedance at the input and the output adds additional power gain as can be seen in Table 1. These higher impedance levels can be useful in interfacing with active mixers which can have output impedance of 400Ω and beyond. Input and Output Common Mode Bias The LTC6410-6 is internally self-biased through the VBIAS pin (see the Block Diagram). Therefore the LTC6410-6 can be AC-coupled with no external biasing circuitry. The output will have approximately the same common mode voltage as the input. In the case of a DC-coupled input connection, the input DC common mode voltage will also set the output common mode voltage. Note that a voltage divider is formed between the VBIAS buffer output and the DC input source impedance. The VBIAS pin has an internal voltage divider which will self bias to approximately 1.4V on a 3V supply (0.47 • VSUPPLY). An external capacitor of 0.1μF to ground is recommended to bypass the pin. The resistance of the pin is 3k. See Distortion vs Common Mode graph. For increased common mode accuracy, the +TERM and –TERM pins can be AC-coupled to the inputs with capacitors (CEXT). This coupling prevents the feedback from the termination resistance from creating additional DC common mode voltage error. The GCM and VOSCM of the DC Electrical Characteristics table reflect the less accurate DC-coupled scenario. The termination inputs are part of a high speed feedback loop. The physical length of the termination loop (REXT and CEXT) must be minimized to maintain stability and minimize gain peaking. Gain Internally, the LTC6410-6 has a voltage gain of 2.7V/V. The default source and load resistances in most of the data sheet are assumed to be 50Ω differential. Due to the input and output resistance of the LTC6410-6 being 58Ω and 22Ω respectively, the overall voltage gain in a 50Ω system is 6dB (2V/V). Other source and load resistances will produce different gains due to the resistive dividers. Figure 1 is a system diagram for calculating gain. RS RIN LTC6410-6 VS ROUT 22Ω RLOAD 64106 F01 Figure 1 64106fa 11 LTC6410-6 APPLICATIONS INFORMATION Therefore the differential voltage gain can be calculated as follows: Voltage Gain = 2• RIN RL • 2.7 • RIN + RS RL + ROUT The following is an example of the 50Ω gain calculation: 58 50 • 2.7 • 58+50 50 + 22 = 2.0V/V = 6.0dB Voltage Gain = 2• Output Impedance The LTC6410-6 is designed to drive a differential load of 50Ω with a total differential output resistance of 22Ω. While the LTC6410-6 can source and sink approximately 50mA, large DC output current should be avoided. To test the part on traditional 50Ω test equipment, AC coupling or balun transformers (or both) may be necessary at the input and output. Supply Rails The part also can be used with different input impedances providing no additional voltage gain, but a higher power gain. For example, the calculation for a 100Ω input impedance shows the effect of an impedance conversion. The voltage gain is calculated as follows: 83 50 • 2.7 • 83+100 50 + 22 = 1.7V/V = 4.6dB Voltage Gain = 2• Inductance in the supply path can severely effect the performance of the LTC6410-6. Therefore it is recommended that low inductance bypass capacitors are installed very close to the part. 680pF and 0.1μF sized capacitors are recommended. Additionally, the exposed pad of the part must be connected to V– for low inductance and low thermal resistance. Failure to provide a low impedance supply at high frequencies can cause oscillations and increased distortion. SHDN However the power gain is: 83 50 Power Gain = 2• • 2.7 • • 2 83+100 50 + 22 = 5.8mW/mW = 7.6dB 2 The SHDN pin self-biases to V+ through a 30k resistor. The pin must be pulled below 0.8V in order to shut down the part. Applications Circuits The graphs on the following page are examples of the four differential input resistances used on the DC1103A demo board with balun transformers for interfacing with the 50Ω single-ended measurement equipment. Table 1. Input Impedance DIFFERENTIAL SOURCE RESISTANCE (Ω) (RS) EXTERNAL TERMINATION RESISTOR (Ω) (REXT) EFFECTIVE DIFFERENTIAL DIFFERENTIAL INPUT LOAD OUTPUT IMPEDANCE (Ω) RESISTANCE (Ω) RESISTANCE (Ω) (RIN) POWER GAIN (dB) VOLTAGE GAIN (SOURCE AND LOAD RESISTANCE AS STATED (V/V) NF AT 10MHz (dB) 50 0 58 50 22 6.0 2.0 11 100 49.9 83 50 22 7.6 1.7 9 200 249 177 50 22 10.9 1.8 7 400 750 377 50 22 14.2 1.8 6 2000 Open 2000 50 22 21.5 1.9 – 64106fa 12 LTC6410-6 APPLICATIONS INFORMATION ZIN = 100Ω, T1 = WBC2-1TL, T2 = ETC1-1-13 ZIN = 50Ω, T1 = ETC1-1-13, T2 = ETC1-1-13 49.9Ω 0.1μF T1 –TERM –IN 1:1 +IN 0.1μF 0.1μF T1 1:1 +OUT 1:2 OUT +IN 0.1μF –5 S22 –15 S11 –25 S12 64106 TA03a ZIN = 100Ω VCC = 3V 15 S21 –35 NOISE FIGURE 5 S21 –5 S22 S11 –15 –25 S12 –35 –45 –45 10 100 1000 FREQUENCY (MHz) 10000 10 100 1000 FREQUENCY (MHz) 64106 TA02b ZIN = 400Ω, T1 = WBC8-1L, T2 = ETC1-1-13 750Ω 249Ω 0.1μF –TERM –IN +IN 0.1μF GAIN AND NOISE FIGURE (dB) 25 S21 5 NOISE FIGURE –5 S22 –15 –IN 1:8 1:1 +OUT OUT +IN 0.1μF ZIN = 200Ω V+ = 3V V– = 0V S11 –25 S12 –35 S21 NOISE FIGURE ZIN = 400Ω V+ = 3V V– = 0V 5 –5 S22 –15 S11 –25 –35 –45 OUT 64106 TA05a 25 15 1:1 +OUT +TERM 750Ω 64106 TA04a T2 –OUT LTC6410-6 ZIN = 400Ω IN +TERM 249Ω 15 –TERM –OUT LTC6410-6 ZIN = 200Ω 0.1μF T1 T2 GAIN AND NOISE FIGURE (dB) 1:4 IN 10000 64106 TA03b ZIN = 200Ω, T1 = WBC4-14L, T2 = ETC1-1-13 T1 OUT +TERM 25 GAIN AND NOISE FIGURE (dB) GAIN AND NOISE FIGURE (dB) 5 1:1 +OUT 49.9Ω ZIN = 50Ω VCC = 3V NOISE FIGURE –OUT LTC6410-6 ZIN = 100Ω IN +TERM 25 T2 –IN 64106 TA03a 15 –TERM –OUT LTC6410-6 ZIN = 50Ω IN T2 S12 –45 10 100 1000 FREQUENCY (MHz) 10000 64106 TA04b 10 100 1000 FREQUENCY (MHz) 10000 64106 TA05b 64106fa 13 LTC6410-6 APPLICATIONS INFORMATION Demoboard DC1103A Top Silkscreen TYPICAL APPLICATION SAW Filter Application The differential output of the LTC6410-6 allows differential driving of the SAW filter without the need for a transformer. The differential nature of the LTC6410-6 allows for ease of use in differential signal chains, and may reduce the need for transformers. 3V 0.1μF –TERM V+ –IN 12.4Ω 47nH –OUT LTC6410-6 15pF +OUT +IN V– 12.4Ω SAWTEK 854923 120nH* 47nH* 64106 TA07 15pF SAW Filter Application +TERM 0.1μF 0 *COILCRAFT 0805CS –10 –20 S21 (dB) The schematic above shows a typical signal chain application with the LTC6410-6 in combination with a 140MHz center frequency 24MHz bandwidth SAW filter. Without the LTC6410-6, the attenuation of the SAW would be –11.5dB. The networks between the LTC6410-6 and the SAW filter, and after the SAW filter are for proper impedance matching. –30 –40 –50 –60 –70 90 100 110 120 130 140 150 160 170 180 190 FREQUENCY (MHz) 64106 TA08 64106fa 14 LTC6410-6 PACKAGE DESCRIPTION UD Package 16-Lead Plastic QFN (3mm × 3mm) (Reference LTC DWG # 05-08-1691) 0.70 p0.05 3.50 p 0.05 1.45 p 0.05 2.10 p 0.05 (4 SIDES) PACKAGE OUTLINE 0.25 p0.05 0.50 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 3.00 p 0.10 (4 SIDES) BOTTOM VIEW—EXPOSED PAD PIN 1 NOTCH R = 0.20 TYP OR 0.25 s 45o CHAMFER R = 0.115 TYP 0.75 p 0.05 15 16 PIN 1 TOP MARK (NOTE 6) 0.40 p 0.10 1 1.45 p 0.10 (4-SIDES) 2 (UD16) QFN 0904 0.200 REF 0.00 – 0.05 NOTE: 1. DRAWING CONFORMS TO JEDEC PACKAGE OUTLINE MO-220 VARIATION (WEED-2) 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 0.25 p 0.05 0.50 BSC 64106fa 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 LTC6410-6 TYPICAL APPLICATION Demoboard DC1103A Schematic VCC TP1 SHDN R16 10Ω C17 680pF JP1 EN C31 0.1μF T1 MABA-007159000000 J1 C26 –IN (1) DS C2 0.1μF 12 R6 0Ω 13 C1 0.1μF V– V– VBIAS V+ R19 OPT 1 TP5 GND R20 OPT C7 0.1μF J6 TEST IN C28 0.1μF TP2 VCC 2.8V TO 5.5V VCC C14 4.7μF 5 3 C16 (1) V– 4 C12 680pF C19 OPT C20 OPT R21 (1) R24 0Ω C22 OPT C34 (1) C30 J4 0.1μF –OUT C3 (1) J5 +OUT C4 0.1μF VCC R23 0Ω C29 0.1μF C15 1μF 2 T2 MABA-007159000000 R15 (1) 6 +OUT V+ TP4 VBIAS T3 MABA-007159000000 7 –OUT +TERM C11 (1) 8 V+ LTC6410-6 +IN 17 9 V– –IN R5 0Ω 16 VCC 10 V+ –TERM R7 0Ω 15 C33 (1) 11 V– SHDN R8 0Ω 14 C25 OPT J2 +IN C32 0.1μF C18 0.1μF C13 0.1μF T4 MABA-007159000000 C6 0.1μF R22 (1) J7 TEST OUT 64106 TA06 C5 0.1μF NOTE: UNLESS OTHERWISE SPECIFIED (1) NOT POPULATED TP3 GND RELATED PARTS PART NUMBER LT1993-2 LT1993-4 LT1993-10 LT5514 LT5522 DESCRIPTION 800MHz Differential Amplifier/ADC Driver 900MHz Differential Amplifier/ADC Driver 700MHz Differential Amplifier/ADC Driver Ultralow Distortion IF Amplifier/ADC Driver 600MHz to 2.7GHz High Signal Level Downconverting Mixer LT5524 LT5525 Low Power, Low Distortion ADC Driver with Digitally Programmable Gain High Linearity, Low Power Downconverting Mixer LT5526 High Linearity, Low Power Downconverting Mixer LT5527 400MHz to 3.7GHz High Signal Level Downconverting Mixer LT5557 400MHz to 3.8GHz High Signal Level Downconverting Mixer LTC6400-20 LTC6401-20 LT6402-6 LT6402-12 LT6402-20 LT6411 1.8GHz Low Noise, Low Distortion ADC Driver for 300MHz IF 1.4GHz Low Noise, Low Distortion ADC Driver for 140MHz IF 300MHz Differential Amplifier/ADC Driver 300MHz Differential Amplifier/ADC Driver 300MHz Differential Amplifier/ADC Driver 650MHz Differential ADC Driver/Dual Selectable Gain Amplifier COMMENTS AV = 2V/V, NF = 12.3dB, OIP3 = 38dBm at 70MHz AV = 4V/V, NF = 14.5dB, OIP3 = 40dBm at 70MHz AV = 10V/V, NF = 12.7dB, OIP3 = 40dBm at 70MHz Digitally Controlled Gain Output IP3 47dBm at 100MHz 4.5V to 5.25V Supply, 25dBm IIP3 at 900MHz, NF = 12.5dB, 50Ω Single-Ended RF and LO Ports, ROUT = 400Ω 450MHz Bandwidth, 40dBm OIP3, 4.5dB to 27dB Gain Control Single-Ended 50Ω RF and LO Ports, 17.6dBm IIP3 at 1900MHz, ICC = 28mA 3V to 5.3V Supply, 16.5dBm IIP3, 100kHz to 2GHz RF, NF = 11dB, ICC = 28mA, –65dBm LO-RF Leakage CG = 2.3dB at 1900MHz, IIP3 = 23.5dBm at 1900MHz, 440mW, ROUT = 415Ω CG = 2.9dB at 1950MHz, IIP3 = 24.7dBm at 1950MHz, 300mW, ROUT = 560Ω AV = 20dB, ZIN = 200Ω, IS(MAX) = 105mA at 25°C AV = 20dB, ZIN = 200Ω, IS(MAX) = 62mA at 25°C AV = 6dB, en = 3.8nV/√Hz at 20MHz, 150mW AV = 12dB, en = 2.6nV/√Hz at 20MHz, 150mW AV = 20dB, en = 1.9nV/√Hz at 20MHz, 150mW 3300V/μs Slew Rate, 16mA Current Consumption, Selectable Gain: AV = –1, 1, 2 64106fa 16 Linear Technology Corporation LT 0908 REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2007