19-4797; Rev 0; 2/99 UAL IT MAN TION K A ET U E L H A EV TA S WS DA FOLLO 10MHz to 500MHz VCO Buffer Amplifiers with Differential Outputs The MAX2470/MAX2471 are flexible, low-cost, highreverse-isolation buffer amplifiers for applications with discrete and module-based VCO designs. Both feature differential 50Ω outputs for driving a single differential (balanced) load or two separate single-ended (unbalanced) 50Ω loads. The MAX2470 offers a single-ended input and has two selectable frequency ranges of operation: 10MHz to 500MHz and 10MHz to 200MHz. The MAX2471 offers a differential input and operates from 10MHz to 500MHz. The MAX2470/MAX2471 also feature high input impedance for maximum flexibility, enabling them to be used with a variety of oscillator topologies. High reverse isolation combined with low supply current make them ideal for applications requiring high performance with low power. These devices are also ideal for use as active baluns. The MAX2470 converts a single-ended input to a differential output. The MAX2471 is useful as a differential buffer stage or to convert from a differential input to two single-ended outputs. The MAX2470 operates from a single +2.7V to +5.5V supply. At -5dBm output power, it consumes 5.5mA in the high-frequency range and only 3.6mA in the low-frequency range. The MAX2471 operates from a +2.7V to +5.5V single supply and consumes 5.5mA. Both devices are available in ultra-small SOT23-6 plastic packages, requiring minimal board space. Features ♦ +2.7V to +5.5V Supply Range ♦ Input Frequency Range High: 10MHz to 500MHz (MAX2470/2471) Low: 10MHz to 200MHz (MAX2470) ♦ >14dB Power Gain at 200MHz ♦ 64dB Typical Reverse Isolation at 200MHz ♦ Low-Distortion Output Drive ♦ Ultra-Small SOT23-6 Package ♦ High Input Impedance ♦ Single-Ended (MAX2470) or Differential (MAX2471) Inputs Ordering Information PART TEMP. RANGE PINPACKAGE SOT TOP MARK MAX2470EUT-T -40°C to +85°C 6 SOT23-6 AAAX MAX2471EUT-T -40°C to +85°C 6 SOT23-6 AAAY Typical Operating Circuits VCC Applications Cellular and PCS Mobile Phones ISM-Band Applications Active Baluns General-Purpose Buffers/Amplifiers HI/LO MAX2470 BIAS OUT IN 50Ω OUT Pin Configuration 50Ω GND VCC TOP VIEW OUT 1 6 VCC MAX2471 BIAS GND 2 MAX2470 MAX2471 5 IN 4 HI/LO (IN) OUT IN 50Ω OUT 3 SOT23-6 IN OUT GND 50Ω ( ) ARE FOR MAX2471 ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. MAX2470/MAX2471 General Description MAX2470/MAX2471 10MHz to 500MHz VCO Buffer Amplifiers with Differential Outputs ABSOLUTE MAXIMUM RATINGS VCC to GND ..............................................................-0.3V to +7V IN to GND......-0.3V to (VCC + 0.3V) or 3.7V (whichever is lower) IN to IN ..................................................................-2.2V to +2.2V HI/LO to GND .............................................-0.3V to (VCC + 0.3V) Continuous Power Dissipation SOT23-6 (derate 8.7mW/°C above +70°C)...................696mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10sec ) ............................+300°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. DC ELECTRICAL CHARACTERISTICS (Typical Operating Circuit, VCC = +2.7V to +5.5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +3V, TA = +25°C.) (Note 1) PARAMETER Supply Voltage Range Supply Current SYMBOL CONDITIONS TYP MAX UNITS 5.5 V No signal 5.1 7.4 HI/LO = VCC POUT = -5dBm, RLOAD = 100Ω diff. 5.5 No signal No signal 3.0 HI/LO = GND POUT = -5dBm, RLOAD = 100Ω diff. 3.6 VCC ICC HI/LO Input Level High VIH HI/LO Input Level Low VIL HI/LO Input Bias Current IIN MIN 2.7 4.5 2.0 V -10 VHI/LO = GND or VCC mA 0.6 V 10 µA AC ELECTRICAL CHARACTERISTICS—MAX2470 (VCC = +3V, HI/LO = VCC, all outputs are differentially measured between OUT and OUT driving a 50Ω load through a 180° hybrid, TA = +25°C, unless otherwise noted.) PARAMETER Input Frequency Range (Note 2) SYMBOL fIN CONDITIONS 10 500 10 200 IS21I2 fIN = 10MHz 14.9 fIN = 200MHz 14.9 fIN = 500MHz, TA = TMIN to TMAX Noise Figure 2 NF 13.3 13.8 fIN = 200MHz 14.1 fIN = 10MHz, HI/LO = GND RSOURCE = 50Ω fOUT = 200MHz, RHI/LO = GND 8.9 fIN = 10MHz fIN = 200MHz, TA = TMIN to TMAX AV MAX HI/LO = GND HI/LO = GND Voltage Gain (Note 4) TYP HI/LO = VCC HI/LO = VCC Gain (Note 3) MIN 9.9 13.4 16 fOUT = 500MHz, HI/LO = VCC 10.2 fOUT = 200MHz, RHI/LO = GND 10.2 UNITS MHz 15.3 dB 15.0 V/V dB _______________________________________________________________________________________ 10MHz to 500MHz VCO Buffer Amplifiers with Differential Outputs (VCC = +3V, HI/LO = VCC, all outputs are differentially measured between OUT and OUT driving a 50Ω load through a 180° hybrid, TA = +25°C, unless otherwise noted.) PARAMETER Maximum Output VSWR (OUT, OUT) (Note 5) SYMBOL VSWROUT CONDITIONS 10MHz < fOUT < 200MHz, HI/LO = GND 1.2:1 IS12I2 HI/LO = GND Isolation OUT to OUT (Note 7) Harmonic Suppression TYP 1.5:1 HI/LO = VCC Reverse Isolation (Note 6) MIN 10MHz < fOUT < 500MHz, HI/LO = VCC fIN = 100MHz 75 fIN = 500MHz 48 fIN = 100MHz 75 fIN = 200MHz 64 fIN = 500MHz, HI/LO = VCC 37 fIN = 200MHz, HI/LO = GND 45 fIN = 500MHz, POUT = -5dBm, HI/LO = VCC -26 fIN = 200MHz, POUT = -5dBm, HI/LO = GND -30 MAX UNITS dB dB dBc AC ELECTRICAL CHARACTERISTICS—MAX2471 (Typical values are measured at VCC = +3V, TA = +25°C, unless otherwise noted.) (Note 8) PARAMETER Input Frequency Range (Note 2) SYMBOL CONDITIONS fIN MIN 10 fIN = 10MHz IS21I2 Gain (Note 3) TYP UNITS 500 MHz 15.9 fIN = 200MHz fIN = 500MHz, TA = TMIN to TMAX MAX 16.9 11.3 15.6 dB 17.8 Voltage Gain (Note 4) AV fIN = 10MHz 16 V/V Noise Figure NF fOUT = 500MHz, RSOURCE = 50Ω 8.4 dB Maximum Output VSWR (OUT, OUT) (Note 5) VSWROUT 10MHz < fOUT < 500MHz 1.5:1 fIN = 100MHz 74 fIN = 500MHz 57 Isolation OUT to OUT (Note 7) fIN = 500MHz 35 dB Harmonic Suppression fIN = 500MHz, POUT = -5dBm -29 dBc IS12I2 Reverse Isolation dB Note 1: Limits are 100% production tested at TA = +25°C. Limits over the entire operating temperature range are guaranteed by design and characterization but are not production tested. Note 2: The part has been characterized over the specified frequency range. Operation outside of this range is possible but not guaranteed. Note 3: Gain specified for POUT = -5dBm. Note 4: Voltage gain measured with no input termination and no output load. Note 5: Output VSWR is a single-ended measurement for each OUT and OUT. Note 6: OUT to IN isolation with OUT terminated with 50Ω. Note 7: Input terminated with 50Ω. Note 8: Unless otherwise noted: all inputs are differentially measured between IN and IN driven by a 50Ω load through a 180° hybrid; all outputs are differentially measured between OUT and OUT driving a 50Ω load through a 180° hybrid. _______________________________________________________________________________________ 3 MAX2470/MAX2471 AC ELECTRICAL CHARACTERISTICS—MAX2470 (continued) Typical Operating Characteristics (VCC = +3.0V, MAX2470 output and MAX2471 input and output measurements taken differentially, TA = +25°C, unless otherwise noted.) TA = +25°C TA = +85°C 3.6 3.5 3.4 TA = -40°C 5.6 5.5 5.4 3.2 TA = +25°C TA = +85°C 5.3 5.2 5.1 TA = -40°C 5.0 4.9 3.3 4.8 3.0 3.5 4.0 4.5 5.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 MAX2470/71-03 HI/LO = GND fIN = 200MHz HI/LO = VCC fIN = 500MHz -30 -28 -26 -24 -22 -20 -18 -16 -14 -12 -10 SUPPLY VOLTAGE (V) INPUT POWER (dBm) MAX2470 TRANSDUCER GAIN vs. FREQUENCY (HI/LO = GND) MAX2470 TRANSDUCER GAIN vs. FREQUENCY (HI/LO = VCC) MAX2470 NOISE FIGURE vs. FREQUENCY (HI/LO = GND) 15.0 17.0 12.0 MAX2470/71-05 TA = -40°C TA = -40°C 16.0 HI/LO = GND 11.5 NOISE FIGURE (dB) 15.0 TA = +25°C TA = +25°C IS21I2 (dB) 13.0 TA = +85°C 12.0 14.0 12.0 10.0 11.0 9.0 HI/LO = GND TA = +85°C 13.0 11.0 100 150 200 10.5 HI/LO = VCC 9.5 9.0 50 11.0 10.0 10.0 8.0 0 100 200 300 400 0 500 50 150 100 200 FREQUENCY (MHz) FREQUENCY (MHz) FREQUENCY (MHz) MAX2470 NOISE FIGURE vs. FREQUENCY (HI/LO = VCC) MAX2470 REAL INPUT IMPEDANCE vs. FREQUENCY MAX2470 IMAGINARY INPUT IMPEDANCE vs. FREQUENCY 10,000 HI/LO = VCC 11.5 0 MAX2470/71-09 HI/LO = VCC MAX2470/71-08 12.0 MAX2470/71-07 0 0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -10 -11 -12 -13 -14 -15 -16 SUPPLY VOLTAGE (V) 16.0 14.0 5.5 MAX2470/71-04 2.5 HI/LO = VCC -500 RE [ZIN] (Ω) 1000 11.0 IM [ZIN] (Ω) IS21I2 (dB) 5.7 OUTPUT POWER (dBm) 3.7 -5dBm OUTPUT POWER fIN = 500MHz HI/LO = GND (MAX2470) 5.8 SUPPLY CURRENT (mA) SUPPLY CURRENT (mA) 3.8 MAX2470 OUTPUT POWER vs. INPUT POWER MAX2470/71-02 -5dBm OUTPUT POWER fIN = 200MHz HI/LO = GND 3.9 6.0 5.9 MAX2470/71-01 4.0 MAX2470 (HI/LO = VCC) AND MAX2471 SUPPLY CURRENT vs. SUPPLY VOLTAGE MAX2470/71-06 MAX2470 SUPPLY CURRENT vs. SUPPLY VOLTAGE (HI/LO = GND) NOISE FIGURE (dB) MAX2470/MAX2471 10MHz to 500MHz VCO Buffer Amplifiers with Differential Outputs 100 -1000 -1500 -2000 10.5 10 10.0 1 0 100 200 300 FREQUENCY (MHz) 4 -2500 400 500 -3000 0 50 100 150 200 250 300 350 400 450 500 FREQUENCY (MHz) 0 100 200 300 FREQUENCY (MHz) _______________________________________________________________________________________ 400 500 10MHz to 500MHz VCO Buffer Amplifiers with Differential Outputs MAX2470 OUTPUT VSWR vs. FREQUENCY 1.25 OUT OUT TO IN 60 50 40 100 200 300 400 500 MAX2470/71-12 0 -2 fIN = 200MHz fIN = 500MHz -4 -6 -8 -10 OUT TO OUT INPUT TERMINATED IN 50Ω -12 20 -14 0 100 200 300 400 -30 -28 -26 -24 -22 -20 -18 -16 -14 -12 -10 500 FREQUENCY (MHz) FREQUENCY (MHz) INPUT POWER (dBm) MAX2471 DIFFERENTIAL TRANSDUCER POWER GAIN vs. FREQUENCY MAX2471 NOISE FIGURE vs. FREQUENCY MAX2471 REAL INPUT IMPEDANCE vs. FREQUENCY TA = +85°C 16.0 8.25 NOISE FIGURE (dB) 16.5 TA = -40°C 15.5 10,000 MAX2470/71-15 17.0 8.50 1000 RE [ZIN] (Ω) TA = +25°C MAX2470/71-14 17.5 MAX2470/71-13 0 8.00 7.75 100 15.0 10 7.50 14.0 1 7.25 50 100 150 200 250 300 350 400 450 500 0 0 50 100 150 200 250 300 350 400 450 500 50 100 150 200 250 300 350 400 450 500 FREQUENCY (MHz) FREQUENCY (MHz) FREQUENCY (MHz) MAX2471 IMAGINARY INPUT IMPEDANCE vs. FREQUENCY MAX2471 OUTPUT VSWR vs. FREQUENCY MAX2471 OUTPUT ISOLATION vs. FREQUENCY 1.50 MAX2470/71-16 500 IM [ZIN] (Ω) OUTPUT VSWR 0 INPUT TERMINATED SINGLE-ENDED MEASUREMENT VSWR OUT 1.25 90 OUTPUT ISOLATION (dB) 0 VSWR OUT -500 80 SINGLE-ENDED MEASUREMENT 70 OUT TO IN MAX2470/71-18 14.5 MAX2470/71-17 TRANSDUCER POWER GAIN (dB) 2 MAX2470/71-11 OUT TO IN 70 30 1.00 MAX2471 OUTPUT POWER vs. INPUT POWER OUTPUT POWER (dBm) OUT HI/LO = VCC SINGLE-ENDED MEASUREMENT 80 OUTPUT ISOLATION (dB) HI/LO = VCC INPUT TERMINATED IN 50Ω SINGLE-ENDED MEASUREMENT OUTPUT VSWR 90 MAX2470/71-10 1.50 MAX2470 OUTPUT ISOLATION vs. FREQUENCY 60 50 40 OUT TO OUT 30 INPUT TERMINATED IN 50Ω 1.00 -1000 0 100 200 300 FREQUENCY (MHz) 400 500 20 0 100 200 300 FREQUENCY (MHz) 400 500 0 100 200 300 400 500 FREQUENCY (MHz) _______________________________________________________________________________________ 5 MAX2470/MAX2471 Typical Operating Characteristics (continued) (VCC = +3.0V, MAX2470 output and MAX2471 input and output measurements taken differentially, TA = +25°C unless otherwise noted.) 10MHz to 500MHz VCO Buffer Amplifiers with Differential Outputs MAX2470/MAX2471 Pin Description PIN NAME FUNCTION 1 OUT Differential Noninverting Buffer Output. Broadband 50Ω output. AC coupling is required. Do not DC couple to this pin. 2 2 GND RF Ground. Connect to the ground plane as close as possible to the IC to minimize ground path inductance. 3 3 OUT Differential Inverting Buffer Output. Broadband 50Ω output. AC coupling is required. Do not DC couple to this pin. 4 — HI/LO Bias and Bandwidth Control Input. Connect to VCC to set internal bias for higher bandwidth operation (10MHz to 500MHz). Connect to GND to set internal bias for lower bandwidth operation (10MHz to 200MHz) and to reduce overall current consumption. — 4 IN Differential Inverting Buffer Input. High impedance input to buffer amplifier. See Setting The Input Impedance section. 5 5 IN Differential Noninverting Buffer Input. High impedance to buffer amplifier. See Setting The Input Impedance section. 6 6 VCC MAX2470 MAX2471 1 Supply Voltage Input. +2.7V < VCC < +5.5V. _______________ Detailed Description Bandwidth Control Circuitry The MAX2470 features a logic-controlled bias circuit which optimizes the performance for input frequencies from 10MHz to 500MHz (HI/LO = VCC) and 10MHz to 200MHz (HI/LO = GND). Operating with HI/LO = GND significantly reduces power consumption. __________ Applications Information Input Considerations The MAX2470/MAX2471 offer high-impedance inputs, ideal for low-distortion buffering of a VCO. For applications with discrete transistor-based oscillator designs, simply AC-couple the oscillator directly to the inputs. The buffer’s high input impedance results in minimal loading on the oscillator. For still higher real input impedance and reduced loading effects, match the inputs with a shunt-L matching circuit followed by a series blocking capacitor. For use with 50Ω VCO modules, terminate the buffer input(s) with a 50Ω shunt resistor followed by a series-blocking capacitor. This provides a very stable 50Ω termination and increases reverse isolation. For those applications needing both high gain and good input match, reactively match the buffer inputs to 50Ω with simple two-element matching circuits followed by a series blocking capacitor. 6 Output Considerations The MAX2470 and MAX2471 incorporate fully differential output stages capable of driving an AC-coupled 100Ω differential load or two AC-coupled 50Ω singleended loads. This is ideal for applications that require the oscillator to drive two application circuits (e.g. mixer and PLL) simultaneously. The high output-to-output isolation ensures minimal interaction between multiple load circuits. Layout and Power-Supply Bypassing A properly designed PC board is essential to any RF/ microwave circuit. Be sure to use controlled impedance lines on all high-frequency inputs and outputs. Bypass the power supply with decoupling capacitors as close to the VCC pins as possible. For long VCC lines (inductive), it may be necessary to add additional decoupling capacitors located further away from the device package. Proper grounding of GND is essential. If the PC board uses a topside RF ground, connect GND directly to it. For a board where the ground plane is not on the component side, the best technique is to connect GND to the board with a plated through-hole (via) to the ground plane close to the package. _______________________________________________________________________________________ 10MHz to 500MHz VCO Buffer Amplifiers with Differential Outputs TRANSISTOR COUNT: 67 6LSOT.EPS Package Information _______________________________________________________________________________________ 7 MAX2470/MAX2471 Chip Information MAX2470/MAX2471 10MHz to 500MHz VCO Buffer Amplifiers with Differential Outputs NOTES 8 _______________________________________________________________________________________