LMX2216M

LMX2216 0 1 GHz to 2 0 GHz Low Noise Amplifier Mixer for RF Personal Communications August 1995 LMX2216 0 1 GHz to 2 0 GHz Low Noise Amplifier Mixer for RF Personal Communications General Description The LMX2216 is a monolithic integrated low noise amplifier (LNA) and mixer suitable as a first stage amplifier and downconverter for RF receiver applications The wideband operating capabilities of the LMX2216 allow it to function over frequencies from 0 1 GHz to 2 0 GHz It is fabricated using National Semiconductor’s ABiC IV BiCMOS process All input and output ports of the LMX2216 are single-ended The LNA input and output ports are designed to interface to a 50X system The Mixer input ports are matched to 50X The output port is matched to 200X The only external components required are DC blocking capacitors The balanced architecture of the LMX2216 maintains consistent operating parameters from unit to unit since it is implemented in a monolithic device This consistency provides manufacturers a significant advantage since tuning procedures often needed with discrete designs can be reduced or eliminated The low noise amplifier produces very flat gain over the entire operating range The doubly-balanced Gilbert-cell mixer provides good LO-RF isolation and cancellation of secondorder distortion products A power down feature is implemented on the LMX2216 that is especially useful for standby operation common in Time Division Multiple Access (TDMA) and Time Division Duplex (TDD) systems The LMX2216 is available in a narrow-body 16-pin surface mount plastic package Features Y Y Y Y Y Y Y Y Y Wideband RF operation from 0 1 GHz to 2 0 GHz No external biasing components necessary 3V operation LNA input and output ports matched to 50X Mixer input ports matched to 50X output port matched to 200X Doubly balanced Gilbert cell mixer (single ended input and output) Low power consumption Power down feature Small outline plastic surface mount package Applications Y Y Y Y Y Digital European Cordless Telecommunications (DECT) Portable wireless communications (PCS PCN cordless) Wireless local area networks (WLANs) Digital cellular telephone systems Other wireless communications systems Functional Block Pin Diagram TL W 11814 – 1 Order Number LMX2216M See NS Package Number M16A C1995 National Semiconductor Corporation TL W 11814 RRD-B30M115 Printed in U S A Pin Description Pin No 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Pin Name VCC M GND LNAIN GND GND RFIN GND PWDN IFOUT GND LOIN GND GND LNAOUT GND VCC A I O I I O I I IO I Description Voltage supply for the mixer The input voltage level to this pin should be a DC Voltage ranging from 2 85V to 3 15V Ground RF input signal to the LNA External DC blocking capacitor is required Ground Ground RF input to the mixer The RF signal to be down converted is connected to this pin External DC blocking capacitor is required Ground Power down signal pin Both the LNA and mixer are powered down when a HIGH level is applied to this pin (VIH) IF output signal of the mixer External DC blocking capacitor is required Ground Local oscillator input signal to the mixer External DC blocking capacitor is required Ground Ground Output of the LNA This pin outputs the amplified RF signal External DC blocking capacitor is required Ground LNA supply Voltage DC Voltage ranging from 2 85V to 3 15V Absolute Maximum Ratings If Military Aerospace specified devices are required please contact the National Semiconductor Sales Office Distributors for availability and specifications Supply Voltage (VCC) 6 5V Storage Temperature (TS) Operating Temperature (TO) b 65 C to a 150 C b 40 C to a 85 C Recommended Operating Conditions Supply Voltage (VCC) Operating Temperature (TA) RFIN LOIN 2 85V – 3 15V b 10 C to a 70 C 0 1 GHz to 2 0 GHz 0 1 GHz to 2 0 GHz 2 Electrical Characteristics LNA (VCC e a 3 0V g 5% TA e 25 C Zo e 50X and fIN e 2 0 GHz Symbol ICC ICC-PWDN G P1dB OIP3 NF RLIN RLOUT Supply Current Supply Current Gain Output 1 dB Compression Point Output 3rd Order Intercept Point Single Side Band Noise Figure Input Return Loss Output Return Loss 10 10 Parameter b 30 dBm unless otherwise specified ) Conditions In Operation In Power Down Mode Min Typ 65 Max 80 10 Units mA mA dB dBm dBm 9 b5 0 10 b3 0 50 70 48 15 11 60 dB dB dB Electrical Characteristics Mixer b 30 dBm fLO e 1 89 GHz (VCC e a 3 0V g 5% TA e 25 C Zo e 50X fRF e 2 0 GHz 0 dBm fIF e 110 MHz unless otherwise specified ) Parameter Conditions In Operation In Power Down Mode 40 b 13 0 b3 0 Symbol ICC ICC-PWDN GC P1dB OIP3 SSB NF DSB NF LO-RF LO-IF RF RL LO RL IF RL ZIF Supply Current Supply Current Min Typ 90 Max 12 0 10 Units mA mA dB dBm dBm Conversion Gain (Single Side Band) Output 1 dB Compression Point Output Third Order Intercept Point Single Side Band Noise Figure Double Side Band Noise Figure LO to RF Isolation LO to IF Isolation RF Return Loss LO Return Loss IF Return Loss IF Port Impedance 60 b9 0 00 17 14 18 15 dB dB dB dB dB dB dB X 20 20 10 10 30 30 15 15 15 200 Electrical Characteristics Power Down Symbol VIH VIL IIH IIL Parameter High Level Input Voltage Low Level Input Voltage High Level Input Current Low Level Input Current VIH e VCC VIL e GND b 10 0 b 10 0 Conditions Min VCC b 0 8 Typ Max Units V 08 10 0 10 0 V mA mA 3 Typical Application Block Diagram TL W 11814 – 2 FIGURE 2 Typical Characteristics LNA LNA Current Composition vs Supply Voltage with Temperature as a Parameter LNA POUT vs PIN with Supply Voltage as a Parameter TL W 11814–3 TL W 11814 – 4 LNA POUT vs PIN with Temperature as a Parameter LNA POUT vs PIN with Temperature as a Parameter TL W 11814–6 TL W 11814 – 7 4 Typical Characteristics (Continued) LNA (Continued) LNA Gain vs Frequency with Supply Voltage as a Parameter LNA Noise Figure vs Frequency with Supply Voltage as a Parameter TL W 11814 – 8 TL W 11814 – 9 LNA Gain vs Frequency with Temperature as a Parameter LNA Noise Figure vs Frequency with Temperature as a Parameter TL W 11814 – 10 TL W 11814 – 11 LNA Input Return Loss vs Frequency with Voltage as a Parameter LNA Output Return Loss vs Frequency with Voltage as a Parameter TL W 11814 – 12 TL W 11814 – 19 5 Typical Characteristics (Continued) MIXER Mixer Gain (Double Sideband) vs Frequency with Supply Voltage as a Parameter Mixer Gain (Double Sideband) vs Frequency with Temperature as a Parameter TL W 11814–20 TL W 11814 – 21 Mixer Noise Figure (Double Sideband) vs Frequency with Supply Voltage as a Parameter Mixer Noise Figure (Double Sideband) vs Frequency with Temperature as a Parameter TL W 11814–22 TL W 11814 – 23 6 Typical Characteristics (Continued) MIXER (Continued) Mixer POUT vs PIN with Supply Voltage as a Parameter Mixer POUT vs PIN with Supply Voltage as a Parameter TL W 11814 – 24 TL W 11814 – 25 Mixer POUT vs PIN with Temperature as a Parameter Mixer POUT vs PIN with Temperature as a Parameter TL W 11814 – 26 TL W 11814 – 27 Mixer RFIN Return Loss vs Frequency with Supply Voltage as a Parameter Mixer RFIN Return Loss vs Frequency with Supply Voltage as a Parameter TL W 11814 – 28 TL W 11814 – 29 7 Typical Characteristics (Continued) MIXER (Continued) Mixer RFIN Return Loss vs Frequency with Supply Voltage as a Parameter Mixer IFOUT Return Loss vs Frequency with Supply Voltage as a Parameter TL W 11814–30 TL W 11814 – 31 Functional Description TL W 11814 – 13 FIGURE 3 Block Diagram of the LMX2216 8 Functional Description (Continued) THE LNA The LNA is a common emitter stage with active feedback This feedback network allows for wide bandwidth operation while providing the necessary optimal input impedance for low noise performance The power down feature is implemented using a CMOS buffer and a power-down switch The power down switch is implemented with CMOS devices During power down the switch is open and only leakage currents are drawn from the supply THE MIXER The mixer is a Gilbert cell architecture with the RF input signal modulating the LO signal and single ended output taken from the collector of one of the upper four transistors The power down circuitry of the mixer is similar to that of the LNA The power down switch is used to provide or cut off bias to the Gilbert cell Typical Gilbert Cell Typical Low Noise Amplifier TL W 11814 – 15 TL W 11814 – 14 FIGURE 4 Typical LNA Structure A typical low noise amplifier consists of an active amplifying element and input and output matching networks The input matching network is usually optimized for noise performance and the output matching network for gain The active element is chosen such that it has the lowest optimal noise figure FMIN an intrinsic property of the device The noise figure of a linear two-port is a function of the source admittance and can be expressed by F e FMIN a where GG a jBG Rn (GON b GG)2 a (BON b BG)2 GG e generator admittance presented to FIGURE 5 Typical Gilbert Cell Circuit Diagram The Gilbert cell shown above is a circuit which multiplies two input signals RF and LO The input RF voltage differentially modulates the currents on the collectors of the transistors Q1 and Q2 which in turn modulate the LO voltage by varying the bias currents of the transistors Q3 Q4 Q5 and Q6 Assuming that the two signals are small the result is a product of the two signals producing at the output a sum and difference of the frequencies of the two input signals If either of these two signals are much larger than the threshold voltage VT the output will contain other mixing products and higher order terms which are undesirable and may need to be attenuated or filtered out Analysis of the Gilbert cell shows that the output which is the difference of the collector currents of Q3 and Q6 is related to the two inputs by the equation DI e IC3 b IC6 e IEE tanh the input of the two port GON a jBON e generator admittance at which optimum noise figure occurs e empirical constant relating the Rn sensitivity of the noise figure to generator admittance and the hyperbolic tangent function can be expressed as a Taylor series tanh(x) e x b x3 x5 a b 3 5  2V J ( VRF T tanh  2V J ( VLO T Assuming that the RF and LO signals are sinusoids VRF e Acos (0RF t a wRF) VLO e Bcos (0LO t a wLO) then DI e IEE Acos (0RF t a wRF) b A3 cos3 (0RF t a wRF ) a 3 B3  Bcos (0LO t a wLO) b cos3 (0LO t a wLO) a 3 ( ( The lowest order term is a product of two sinusoids yielding a sum of two sinusoids AB cos ((0RF a 0LO) t a wRF a wLO) 2 a cos ((0RF b 0LO) t a wRF b wLO) one of which is the desired intermediate frequency signal IEE ( 9 Figures of Merit GAIN (G) Many different types of gain are specified in RF engineering The type referred to here is called transducer gain and is defined as the ratio of the power delivered to the load to the available power from the source RV POUT V R e OUT L e 4 S OUT Ge 2 2 PIN V IN RS RL V IN where VOUT is the voltage across the load RL and VIN is the generator voltage with internal resistance RS In terms of scattering parameters transducer gain is defined as G e 20 log (lS21l) where S21 is the forward transmission parameter which can be measured using a network analyzer 1 dB COMPRESSION POINT (P1dB) A measure of amplitude Iinearity 1 dB compression point is the point at which the actual gain is 1dB below the ideal linear gain For a memoryless two-port with weak nonlinearity the output can be represented by a power series of the input as 2 3 vo e k1 vi a k2 v i a k3 v i a For a sinusoidal input vi e Acos 01t the output is 1 3 k2 A2 a k1 A a k3 A3 cos 01 t vo e 2 4 1 1 a k2 A2 cos 201 t a k3 A3 cos 301 t 2 4 TL W 11814 – 16 2 2 FIGURE 6 Typical POUT –PIN Characteristics NOISE FIGURE (NF) Noise figure is defined as the input signal to noise ratio divided by the output signal to noise ratio For an amplifier it can also be interpreted as the amount of noise introduced by the amplifier itself seen at the output Mathematically Fe Si Ni Si Ni N a Ga Ni e ea So No Ga Si (Na a Ga Ni) Ga Ni  J assuming that all of the fourth and higher order terms are negligible For an amplifier the fundamental component is the desired output and it can be rewritten as k1 A 1 a 3 (k3 k1) A2 4 This fundamental component is larger than k1 A (the ideally linear gain) if k3 l 0 and smaller if k3 k 0 For most practical devices k3 k 0 and the gain compresses as the amplitude A of the input signal gets larger The 1 dB compression point can be expressed in terms of either the input power or the output power Measurement of P1dB can be made by increasing the input power while observing the output power until the gain is compressed by 1 dB THIRD ORDER INTERCEPT (OIP3) Third order intercept is another figure of merit used to characterize the linearity of a two-port It is defined as the point at which the third order intermodulation product equals the ideal linear uncompressed output Unlike the P1dB OIP3 involves two input signals However it can be shown mathematically (similar derivation as above) that the two are closely related and OIP3 P1dB a 10 dB Theses two figures of merit are illustrated in Figure 6 ( NF e 10 log (F) where Si and Ni represent the signal and noise power levels available at the input to the amplifier So and No the signal and noise power levels available at the output Ga the available gain and Na the noise added by the amplifier Noise figure is an important figure of merit used to characterize the performance of not only a single component but also the entire system It is one of the factors which determine the system sensitivity IMAGE FREQUENCY DSB SSB NF Image frequency refers to that frequency which is also down-converted by the mixer along with the desired RF component to the intermediate frequency This image frequency is located at the same distance away from the LO but on the opposite side of the RF For most mixers it must be filtered out before the signal is down-converted otherwise an image-reject mixer must be used Figure 7 illustrates the concept TL W 11814 – 17 FIGURE 7 Input and Output Spectrum of Mixers 10 Figures of Merit (Continued) Due to the presence of image frequencies and the method in which noise figure is defined noise figures can be measured and specified in two ways double side band (DSB) or single side band (SSB) In DSB measurements the image frequency component of the input noise source is not filtered and contributes to the total output noise at the intermediate frequency In SSB measurements the image frequency is filtered and the output noise is not caused by this frequency component In most mixer applications where only one side band is wanted SSB noise figure is 3 dB higher than DSB noise figure In this application the LMX2216 is used in a radio receiver front end where it amplifies the signal from the antenna and then down converts it to an intermediate frequency The image filter placed between the LNA and the mixer attenuates the image frequency The mixer is shown to use an LO signal generated by a PLL synthesizer but depending on the type of application the LO signal could be generated by a device as simple as a free-running oscillator The IF output is then typically filtered by a channel-select filter following the mixer and this signal can then be demodulated or go through another down conversion depending upon the intermediate frequency and system requirements This external filter rejects adjacent channels and also attenuates any LO feed through Figure 9 shows a cascade analysis of a typical RF front-end subsystem in which the LMX2216 is used It includes the bandpass filter and the switch through which the input RF signal goes in a radio system before reaching the LNA Typical values are used for the insertion loss of the various filters in this example TL W 11814 – 18 FIGURE 8 Typical Applications Circuit of the LMX2216 1 2 3 4 5 6 Comp Filter Switch LNA Filter Mixer Filter Data per Stage Gain N Fig b2 0 20 b0 6 06 12 3 37 b3 0 30 58 13 7 b3 0 30 Gain N Fig IIP3 OIP3 OIP3 100 0 100 0 60 100 0 30 100 0 1 2 3 4 5 6 Gain b2 0 b2 6 97 67 12 5 95 Cumulative Data N Fig IIP3 20 97 9 26 96 6 b3 7 63 b3 7 64 b 10 5 96 b 10 5 97 OIP3 95 9 94 0 60 30 20 b1 0 System Cumulative Values 9 5 dB 9 7 dB b 10 5 dBm b 1 0 dBm FIGURE 9 Cascade Analysis Example 11 LMX2216 0 1 GHz to 2 0 GHz Low Noise Amplifier Mixer for RF Personal Communications Physical Dimensions inches (millimeters) JEDEC 16-Lead (0 150 Wide) Small Outline Molded Package (M) Order Number LMX2216M For Tape and Reel Order Number LMX2216MX NS Package Number M16A LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMICONDUCTOR CORPORATION As used herein 1 Life support devices or systems are devices or systems which (a) are intended for surgical implant into the body or (b) support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected to result in a significant injury to the user National Semiconductor Corporation 1111 West Bardin Road Arlington TX 76017 Tel 1(800) 272-9959 Fax 1(800) 737-7018 2 A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness National Semiconductor Europe Fax (a49) 0-180-530 85 86 Email cnjwge tevm2 nsc com Deutsch Tel (a49) 0-180-530 85 85 English Tel (a49) 0-180-532 78 32 Fran ais Tel (a49) 0-180-532 93 58 Italiano Tel (a49) 0-180-534 16 80 National Semiconductor Hong Kong Ltd 13th Floor Straight Block Ocean Centre 5 Canton Rd Tsimshatsui Kowloon Hong Kong Tel (852) 2737-1600 Fax (852) 2736-9960 National Semiconductor Japan Ltd Tel 81-043-299-2309 Fax 81-043-299-2408 National does not assume any responsibility for use of any circuitry described no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications