RF2504

RF2504 RFMD | Alldatasheet

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Functional Block Diagram RF Micro Devices, Inc.

7628 Thorndike Road

Greensboro, NC 27409, USA T el (336) 664 1233 Fax (336) 664 0454 http://www.rfmd.com Optimum Technology Matching® Applied Si BJT GaAs MESFETGaAs HBT Si Bi-CMOS SiGe HBT Si CMOS VCC1 RES GND1 NC PD GND2 RF OUT VCC2 RF2504 VCO/HIGH-ISOLATION BUFFER AMPLIFIER

• 2-Way Paging  ISM Band Systems  Wireless Local Loop Systems  GPS Receivers  Cellular Systems  Low Voltage Applications The RF2504 is an integrated oscillator and buffer ampli- fier chain designed to achieve extremely low sensitivity to fluctuations in load impedance and power supply noise, thereby greatly reducing load pulling and pushing. The IC offers great flexibility, yet is easy to use. This product was designed for use in applications with low supply voltages. It has a power-down feature and is designed to operate from 700MHz to 1500MHz with the help of an external resonator. Frequency control is achieved with an external varactor diode. The IC’s ease of use, reduced load pull- ing, small size, and low cost make it an ideal LO (Local Oscillator) for almost any wireless application.  High-Isolation / Reduced Load Pulling  Low Current Consumption  -6dBm Output Power  Digitally Controlled Power Down Mode  700MHz to 1500MHz Operating Range  Single 2.2V to 5V Supply RF2504 VCO/High-Isolation Buffer Amplifier RF2504 PCBA Fully Assembled Evaluation Board Rev A2 010117 0.244 0.229 0.157 0.150 0.018 0.014 0.050 0.068 0.053 NOTES: 1. Shaded lead is Pin 1. 2. All dimensions are excluding mold flash. 3. Lead coplanarity - 0.005 with respect to datum "A". Dimensions in mm 0.196 0.189 0.008 0.004 -A- 8° MAX 0° MIN 0.034 0.016 0.009 0.007 Package Style: SOIC-8

Supply Voltage -0.5 to +5.8 V DC Power Down Voltage (VPD )- 0 . 5 t o + 5 . 8 V DC Operating Ambient Temperature -40 to +85 °C Storage Temperature -55 to +150 °C Parameter Specification Unit ConditionMin. Typ. Max. Overall Operating Frequency 700 to 1500 MHz 915MHz Operation T=25° C, VCC =2.7V , ZLOAD =50 Ω , VPD =2.7V Output Power -6 dBm 2nd Harmonic -8 dBc 3rd Harmonic -19 dBc Load Pulling 200 kHz Into 1.67VSWR Load VCC Pushing 4.7 MHz/V Phase Noise -104 dBc 100kHz Offset. Better phase noise is achiev- able at the expense of output power. -83 dBc 10kHz Offset Power Supply Operating Voltage 2.2 to 5.0 V DC At 2.2V and -40°C, output power will be reduced to typically -11dBm. Supply Current 5.5 mA Caution!ESD sensitive device. RF Micro Devices believes the furnished information is correct and accurate at the time of this printing. However, RF Micro Devices reserves the right to make changes to its products without notice. RF Micro Devices does not assume responsibility for the use of the described product(s).

Pin Function Description Interface Schematic 1V C C 1 Power supply connection for the VCO. This pin should be well bypassed close to the package with a capacitor suitable for the fre- quency of operation as well as a capacitor to minimize low frequency noise from the voltage supply. The ground side of the capacitors should connect immediately to ground plane. 2R E S Connection point for the resonator circuit. The resonator is an inductive element. Changing the effective inductance, either physically or with a varactor tuned circuit, will change the frequency of operation. Note that all parasitics on the circuit board will contribute to the effective induc- tance and will influence the frequency of operation. These effects become more pronounced at higher operating frequencies. This pin has DC bias present. A DC blocking capacitor, suitable for the fre- quency of operation, should be used if the external circuitry has DC present or presents a DC path to ground. See Application Example Schematic and Theory of Operation section of this data sheet for design details. 3G N D 1 Ground connection for the VCO. Keep traces physically short and con- nect immediately to ground plane for best performance. In order to min- imize load pulling, it is recommended that pin 3 have a different return path to ground than pin 7 (i.e., separate vias to a common ground plane). See Pin 2 4N C Not connected. 5V C C 2 Power supply connection for the buffer amplifiers. This pin should be well bypassed close to the package with a capacitor suitable for the fre- quency of operation. The ground side of the capacitor should connect immediately to ground plane. 6R F O U T RF output pin. This is an open-collector output and must be biased externally. A shunt bias/matching inductor to V CC and a series blocking/ matching capacitor are recommended. See Application Example Sche- matic. 7G N D 3 Ground connection for the buffer amplifiers. Keep traces physically short and connect immediately to ground plane for best performance. In order to minimize load pulling, it is recommended that pin 3 have a different return path to ground than pin 7 (i.e., separate vias to a com- mon ground plane). 8P D Power Down pin for the VCO and buffer amplifiers. A logic “low” (0.0 to 0.7V) turns the entire device off and supply current drops to less than 1µA. A logic “high” (≥ 3.0V) turns the device on. Note that the voltage on this pin should never exceed 5.5V DC . Pins 3,4 Pin 2 To Buffer Amps and Bias Ckts. To Bias Ckts.

The RF2504 has two functional parts: an oscillator and buffer amplifier. The functional blocks have separate ground and VCC pins to increase the isolation and reduce load pulling, one of the key design objectives. An external resonator is used to add design flexibility, and the loaded Q of this resonator will affect the perfor- mance of the resulting oscillator. To create an oscillation, negative resistance is gener- ated at pin 2 with a circuit similar to a Colpitts oscillator. The input impedance at pin 2, measured with a vector network analyzer, is shown here in the data sheet. In general, the impedance looks like a negative resis- tance in series with a capacitor. The negative resis- tance decays as the frequency increases. An oscillator is created when an inductive element is placed on pin 2 that is the conjugate of the capacitive reactance. A greater inductive element will create a lower frequency of oscillation. T h eS 1 1l o o k i n gi n t op i n2i sa l s os h o w nh e r ei nt h e data sheet. It has return gain from 500 MHz to 2200 MHz at room temperature. The specified frequency range of 750 MHz to 1500 MHz defines the region where the output power is relatively flat. At lower and higher frequencies, the power will tend to roll off from the nominal value. The specified frequency range is conservatively set to ensure oscillation and maintain performance, but the RF2504 can be used over a broader frequency range with degraded performance. The overall Q of the external resonator will affect per- formance. Lower Q means lower power, higher phase noise, and more load pulling. If the Q is too low, the cir- cuit will not oscillate. The IC is designed to oscillate into a resonator with Q>10. The performance is mea- sured with a microstrip resonator or high quality induc- tor, which usually has a Q>50. These measurements define the best performance that can be expected from the ICs. Lower Q resonators, particularly those includ- ing a lossy varactor, might have degraded perfor- mance. The specified output power is measured into a 50 Ω load. The IC has a high output impedance, and if desired, output matching can be used to obtain more power by transforming 50 Ω into a higher impedance. On the RF2504, this could be accomplished by simply changing the values of the external output inductor and capacitor.

915 MHz Operation

100 pF12 nH47 kΩ 100 pF SMV1235-011 100 pF1 µ F 100 pF VPD RF OUT 27 nH 100 pF 100 pF VCC

Evaluation Board Schematic 915MHz Operation (Download Bill of Materials from www.rfmd.com.) PD 100 pF 10 µ F VCC 100 pF 10 µ F RF OUT VCC 100 pF 10 µ F 100 pF 12 nH 47 kΩ 100 pF 2504400- P1-1 P1-3 VCC GND PD1 27 nH 100 pF D1* P2-1 NC GND VTUNE1 VTUNE *Alpha SMV1235-011

Board Size 2.0” x 2.0”

VCC = 5.0 V -50.0 -40.0 -30.0 -20.0 -10.0 0.0 10.0 20.0 30.0 40.0 50.0 Frequency (MHz) R (Ohms) -450.0 -400.0 -350.0 -300.0 -250.0 -200.0 -150.0 -100.0 -50.0 0.0 50.0 R Reference A R Reference B X Reference A X Reference B S11 VCC = 2.7 V -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 Frequency (MHz) S11 (dB) Reference A Reference B Evaluation Board Data 880.0 890.0 900.0 910.0 920.0 930.0 940.0 950.0 960.0 VTune (V) Frequency (MHz) -10.0 -9.0 -8.0 -7.0 -6.0 -5.0 -4.0 -3.0 -2.0 -1.0 0.0 Power (dBm) Frequency Power Input Impedance VCC = 2.7 V -50.0 -40.0 -30.0 -20.0 -10.0 0.0 10.0 20.0 30.0 40.0 50.0 Frequency (MHz) R (Ohms) -450.0 -400.0 -350.0 -300.0 -250.0 -200.0 -150.0 -100.0 -50.0 0.0 50.0 X (Ohms) R Reference A R Reference B X Reference B X Reference A Pin 2 0603 100 pF A B Reference positions for input impedance measurements of RF2504