Philips Semiconductors Product specification Double-balanced mixer and oscillator DESCRIPTION NE/SA612A PIN CONFIGURATION The NE/SA612A is a low-power VHF monolithic double-balanced mixer with on-board oscillator and voltage regulator. It is intended for low cost, low power communication systems with signal frequencies to 500MHz and local oscillator frequencies as high as 200MHz. The mixer is a “Gilbert cell” multiplier configuration which provides gain of 14dB or more at 45MHz. D, N Packages The oscillator can be configured for a crystal, a tuned tank operation, or as a buffer for an external L.O. Noise figure at 45MHz is typically below 6dB and makes the device well suited for high performance cordless phone/cellular radio. The low power consumption makes the NE/SA612A excellent for battery operated equipment. Networking and other communications products can benefit from very low radiated energy levels within systems. The NE/SA612A is available in an 8-lead dual in-line plastic package and an 8-lead SO (surface mounted miniature package). INPUT A 1 8 VCC INPUT B 2 7 OSCILLATOR GND 3 6 OSCILLATOR OUTPUT A 4 5 OUTPUT B SR00098 Figure 1. Pin Configuration APPLICATIONS • Cordless telephone • Portable radio • VHF transceivers • RF data links • Sonabuoys • Communications receivers • Broadband LANs • HF and VHF frequency conversion • Cellular radio mixer/oscillator FEATURES • Low current consumption • Low cost • Operation to 500MHz • Low radiated energy • Low external parts count; suitable for crystal/ceramic filter • Excellent sensitivity, gain, and noise figure ORDERING INFORMATION DESCRIPTION TEMPERATURE RANGE ORDER CODE DWG # 0 to +70°C NE612AN SOT97-1 8-Pin Plastic Dual In-Line Plastic (DIP) 8-Pin Plastic Small Outline (SO) package (Surface-Mount) 0 to +70°C NE612AD SOT96-1 8-Pin Plastic Dual In-Line Plastic (DIP) -40 to +85°C SA612AN SOT97-1 8-Pin Plastic Small Outline (SO) package (Surface-Mount) -40 to +85°C SA612AD SOT96-1 BLOCK DIAGRAM 8 7 6 5 V CC OSCILLATOR VOLTAGE REGULATOR GROUND 1 2 3 4 SR00099 Figure 2. Block Diagram 1990 Sep 17 1 853-0391 00446 Philips Semiconductors Product specification Double-balanced mixer and oscillator NE/SA612A ABSOLUTE MAXIMUM RATINGS SYMBOL PARAMETER RATING UNIT VCC Maximum operating voltage 9 V TSTG Storage temperature -65 to +150 °C TA Operating ambient temperature range NE SA 0 to +70 -40 to +85 °C AC/DC ELECTRICAL CHARACTERISTICS TA=25°C, VCC = 6V, Figure 3 SYMBOL VCC PARAMETER TEST CONDITION Power supply voltage range LIMITS Min Typ 4.5 Max 8.0 V DC current drain 2.4 fIN Input signal frequency 500 MHz fOSC Oscillator frequency 200 MHz Noise figured at 45MHz 5.0 dB -13 dBm 17 dB Third-order intercept point at 45MHz RFIN=-45dBm Conversion gain at 45MHz 14 RIN RF input resistance 1.5 CIN RF input capacitance Mixer output resistance (Pin 4 or 5) mA kΩ 3 pF 1.5 kΩ radio 2nd IF and demodulator, the NE/SA612A is capable of receiving -119dBm signals with a 12dB S/N ratio. Third-order intercept is typically -15dBm (that’s approximately +5dBm output intercept because of the RF gain). The system designer must be cognizant of this large signal limitation. When designing LANs or other closed systems where transmission levels are high, and small-signal or signal-to-noise issues not critical, the input to the NE/SA612A should be appropriately scaled. DESCRIPTION OF OPERATION The NE/SA612A is a Gilbert cell, an oscillator/buffer, and a temperature compensated bias network as shown in the equivalent circuit. The Gilbert cell is a differential amplifier (Pins 1 and 2) which drives a balanced switching cell. The differential input stage provides gain and determines the noise figure and signal handling performance of the system. The NE/SA612A is designed for optimum low power performance. When used with the NE614A as a 45MHz cordless phone/cellular 1990 Sep 17 3.0 UNIT 2 Philips Semiconductors Product specification Double-balanced mixer and oscillator NE/SA612A TEST CONFIGURATION 0.5 to 1.3µH 22pF 1nF 5.5µH 34.545MHz THIRD OVERTONE CRYSTAL 10pF VCC 100nF 6.8µF 10nF 8 7 6 5 150pF OUTPUT 1.5 to 44.2µH 612A 330pF 1 2 3 120pF 4 47pF 0.209 to 0.283µH INPUT 220pF 100nF SR00101 Figure 3. Test Configuration 8 VCC 18k BUFFER 6 7 1.5k 1.5k 4 5 25k BIAS BIAS 2 1 BIAS 1.5k 1.5k 3 GND SR00102 Figure 4. Equivalent Circuit 1990 Sep 17 3 Philips Semiconductors Product specification Double-balanced mixer and oscillator NE/SA612A Besides excellent low power performance well into VHF, the NE/SA612A is designed to be flexible. The input, output, and oscillator ports can support a variety of configurations provided the designer understands certain constraints, which will be explained here. permissible oscillation frequency. If the required L.O. is beyond oscillation limits, or the system calls for an external L.O., the external signal can be injected at Pin 6 through a DC blocking capacitor. External L.O. should be 200mVP-P minimum to 300mVP-P maximum. The RF inputs (Pins 1 and 2) are biased internally. They are symmetrical. The equivalent AC input impedance is approximately 1.5k || 3pF through 50MHz. Pins 1 and 2 can be used interchangeably, but they should not be DC biased externally. Figure 5 shows three typical input configurations. Figure 7 shows several proven oscillator circuits. Figure 7a is appropriate for cordless phones/cellular radio. In this circuit a third overtone parallel-mode crystal with approximately 5pF load capacitance should be specified. Capacitor C3 and inductor L1 act as a fundamental trap. In fundamental mode oscillation the trap is omitted. The mixer outputs (Pins 4 and 5) are also internally biased. Each output is connected to the internal positive supply by a 1.5kΩ resistor. This permits direct output termination yet allows for balanced output as well. Figure 6 shows three single-ended output configurations and a balanced output. Figure 8 shows a Colpitts varacter tuned tank oscillator suitable for synthesizer-controlled applications. It is important to buffer the output of this circuit to assure that switching spikes from the first counter or prescaler do not end up in the oscillator spectrum. The dual-gate MOSFET provides optimum isolation with low current. The FET offers good isolation, simplicity, and low current, while the bipolar circuits provide the simple solution for non-critical applications. The resistive divider in the emitter-follower circuit should be chosen to provide the minimum input signal which will assume correct system operation. The oscillator is capable of sustaining oscillation beyond 200MHz in crystal or tuned tank configurations. The upper limit of operation is determined by tank “Q” and required drive levels. The higher the Q of the tank or the smaller the required drive, the higher the 612A 612A 612A 1 2 1 2 1 INPUT a. Single-Ended Tuned Input b. Balanced Input (For Attenuation of Second-Order Products) 2 c. Single-Ended Untuned Input SR00103 Figure 5. Input Configuration 1990 Sep 17 4 Philips Semiconductors Product specification Double-balanced mixer and oscillator NE/SA612A CT* 12pF 5 5 CFU455 or Equivalent 612A 612A Filter K&L 38780 or Equivalent *CT matches 3.5kΩ to next stage 4 4 a. Single-Ended Ceramic Filter b. Single-Ended Crystal Filter 5 5 612A 612A 4 4 c. Single-Ended IFT d.. Balanced Output SR00104 Figure 6. Output Configuration L1 C2 C3 XTAL 8 7 C1 6 5 8 7 2 5 8 7 612A 612A 1 6 3 4 1 2 5 612A 3 TC02101S a. Colpitts Crystal Oscillator (Overtone Mode) 6 4 1 TC02111S b. Colpitts L/C Tank Oscillator 2 3 4 TC02121S c. Hartley L/C Tank Oscillator SR00105 Figure 7. Oscillator Circuits 1990 Sep 17 5 Philips Semiconductors Product specification Double-balanced mixer and oscillator NE/SA612A 5.5µH +6V 10µF 0.10pF 1 0.1µF 8 2 TO BUFFER 7 612A 10pF 7pF 3 6 4 5 1000pF DC CONTROL VOLTAGE FROM SYNTHESIZER 1000pF 0.06µH MV2105 OR EQUIVALENT 0.01µF 100k 2k 3SK126 2N918 0.01pF 2N5484 2pF TO SYNTHESIZER 330 100k 100k 0.01µF TO SYNTHESIZER 1.0nF SR00106 Figure 8. Colpitts Oscillator Suitable for Synthesizer Applications and Typical Buffers 1990 Sep 17 6 Philips Semiconductors Product specification Double-balanced mixer and oscillator NE/SA612A TEST CONFIGURATION 0.5 to 1.3µH 22pF 44.545MHz THIRD OVERTONE CRYSTAL 5.5µH 6.8µF 5.6pF 1nF VCC 100nF 10nF 8 7 6 5 3 4 612A 1 2 SFG455A3 OR EQUIVALENT 455kHZ 47pF 0.209 to 0.283µH INPUT 45MHz IN 220pF 100nF SR00107 Figure 9. Typical Application for Cordless/Cellular Radio 1990 Sep 17 7 Philips Semiconductors Product specification NE/SA612A 3.50 6.00 3.25 5.75 NOISE FIGURE (dB) SUPPLY CURRENT 9mA) Double-balanced mixer and oscillator 8.5V 3.00 6.0V 2.75 4.5V 2.50 2.25 4.5V 6.0V 8.5V 5.50 5.25 5.00 4.75 2.00 4.50 1.75 4.25 4.00 –40 –30 –20 –10 1.50 –40 –30 –20 –10 0 10 20 30 40 TEMPERATURE OC 50 60 70 0 80 90 10 20 30 40 50 TEMPERATURE OC 60 70 80 90 SR00111 SR00108 Figure 10. ICC vs Supply Voltage Figure 13. Noise Figure RF1 = 45MHz, IF = 455kHz, RF2 = 45.06MHz 20.0 3rd ORDER PRODUCT 19.5 20 18.5 6.0V 8.5V 4.5V 18.0 17.5 17.0 IF OUTPUT POWER (dBm) CONVERSION GAIN (dB) 19.0 16.5 16.0 15.5 15.0 14.5 14.0 –40 –30 –20 –10 0 10 20 30 40 50 60 70 80 0 –20 FUND. PRODUCT –40 –60 90 TEMPERATURE OC SR00109 –80 –60 –40 –20 0 RF INPUT LEVEL (dBm) Figure 11. Conversion Gain vs Supply Voltage 20 SR00112 Figure 14. Third-Order Intercept and Compression –10.0 –11.0 –11.5 –10 –12.0 –11 –12.5 –12 INTERCEPT (dBm) INPUT INTERCEPT POINT (dBm) –10.5 –13.0 –13.5 –14.0 –14.5 –15.0 –15.5 –13 –14 –15 –16 –16.0 –17 –16.5 –17.0 –40 –30 –20 –10 0 10 20 30 40 50 60 70 80 –18 90 TEMPERATURE OC SR00110 4 5 6 7 VCC (VOLTS) Figure 12. Third-Order Intercept Point 8 9 10 SR00113 Figure 15. Input Third-Order Intermod Point vs VCC 1990 Sep 17 8