RO2081A • • • • Ideal for 325 MHz Remote-Control Transmitters Very Low Series Resistance Quartz Stability Surface-Mount, Ceramic Case with 21 mm2 Footprint 325.05 MHz SAW Resonator The RO2081A is a true one-port, surface-acoustic-wave (SAW) resonator in a surface-mount ceramic case. It provides reliable, fundamental-mode, quartz frequency stabilization of fixed-frequency oscillators and low power AM transmitters operating at 325 MHz. Typical applications include remote-control and wireless security alarms for us in Israel. Absolute Maximum Ratings Rating Value Units CW RF Power Dissipation +0 dBm DC Voltage Between Terminals (Observe ESD Precautions) ±30 VDC -40 to +85 °C +250 °C Case Temperature Soldering Temperature SM-2 Case Electrical Characteristics Frequency (+25 °C) Characteristic Nominal Frequency Sym fC Tolerance from 325.050 MHz Insertion Loss Quality Factor Temperature Stability Frequency Aging Notes ∆fC 2, 3, 4, 5 IL 2, 5, 6 Unloaded Q QU 50 Ω Loaded Q QL Turnover Temperature TO Turnover Frequency fO FTC Absolute Value during the First Year |fA| 5 Motional Inductance LM Motional Capacitance CM Shunt Static Capacitance CO 5, 6, 7, 9 LTEST 2, 7 ±150 kHz 2.2 dB 38 53 kHz 0.032 ppm/°C2 ppm/yr 1.0 MΩ 15 5, 6, 7, 9 29 109.341 2.6 Ω µH 2.19259 2.3 Lid Symbolization (in Addition to Lot and/or Date Code) °C fC+2 ±10 1 RM Units MHz 2,000 23 Motional Resistance Maximum 325.200 14,600 6, 7, 8 Frequency Temperature Coefficient Test Fixture Shunt Inductance Typical 1.2 5, 6, 7 DC Insulation Resistance between Any Two Terminals RF Equivalent RLC Model Minimum 324.900 fF 2.9 93 pF nH 189 CAUTION: Electrostatic Sensitive Device. Observe precautions for handling. Notes: 1. 2. 3. 4. 5. 6. 7. Frequency aging is the change in fC with time and is specified at +65°C or less. Aging may exceed the specification for prolonged temperatures above +65°C. Typically, aging is greatest the first year after manufacture, decreasing in subsequent years. The center frequency, fC, is measured at the minimum insertion loss point, ILMIN, with the resonator in the 50 Ω test system (VSWR ≤ 1.2:1). The shunt inductance, LTEST, is tuned for parallel resonance with CO at fC. Typically, fOSCILLATOR or fTRANSMITTER is approximately equal to the resonator fC. One or more of the following United States patents apply: 4,454,488 and 4,616,197. Typically, equipment utilizing this device requires emissions testing and government approval, which is the responsibility of the equipment manufacturer. Unless noted otherwise, case temperature TC = +25°C±2°C. The design, manufacturing process, and specifications of this device are subject to change without notice. Derived mathematically from one or more of the following directly measured parameters: fC, IL, 3 dB bandwidth, fC versus TC, and CO. 8. 9. Turnover temperature, TO, is the temperature of maximum (or turnover) frequency, fO. The nominal frequency at any case temperature, TC, may be calculated from: f = fO [1 - FTC (TO -TC)2]. Typically oscillator TO is approximately equal to the specified resonator TO. This equivalent RLC model approximates resonator performance near the resonant frequency and is provided for reference only. The capacitance CO is the static (nonmotional) capacitance between the two terminals measured at low frequency (10 MHz) with a capacitance meter. The measurement includes parasitic capacitance with "NC” pads unconnected. Case parasitic capacitance is approximately 0.05 pF. Transducer parallel capacitance can by calculated as: CP ≈ CO - 0.05 pF. RF Monolithics, Inc. Phone: (972) 233-2903 Fax: (972) 387-9148 RFM Europe Phone: 44 1963 251383 Fax: 44 1963 251510 ©1999 by RF Monolithics, Inc. The stylized RFM logo are registered trademarks of RF Monolithics, Inc. E-mail: [email protected] http://www.rfm.com RO2081A-061901 Page 1 of 2 325.05 MHz SAW Resonator Equivalent LC Model Electrical Connections The SAW resonator is bidirectional and may be installed with either orientation. The two terminals are interchangeable and unnumbered. The callout NC indicates no internal connection. The NC pads assist with mechanical positioning and stability. External grounding of the NC pads is recommended to help reduce parasitic capacitance in the circuit. Terminal 0.05 pF* Co = Cp + 0.05 pF NC NC Cp *Case Parasitics Terminal Rm Lm Cm Temperature Characteristics The curve shown on the right accounts for resonator contri- The test circuit inductor, LTEST, is tuned to resonate with the static capacitance, CO, at FC. bution only and does not include LC component temperature contributions. ELECTRICAL TEST Network Analyzer 0 -50 -50 -100 -100 -150 -150 -200 -80 -60 -40 -20 Typical Circuit Board Land Pattern To 50 Ω From 50 Ω Network Analyzer fC = f O , T C = T O 0 (f-fo ) / fo (ppm) Typical Test Circuit -200 0 +20 +40 +60 +80 ∆T = T C - T O ( °C ) The circuit board land pattern shown below is one possible design. The optimum land pattern is dependent on the circuit board assembly process which varies by manufacturer. The distance between adjacent land edges should be at a maximum to minimize parasitic capacitance. Trace lengths from terminal lands to other components should be short and wide to minimize parasitic series inductances. (4 Places) Typical Dimension: 0.010 to 0.047 inch (0.25 to 1.20 mm) Case Design The case material is black alumina with contrasting symbolization. All pads are nominally centered with respect to the base and consist of 60 to 100 microinches (min) electroless gold on 50 micorinches (min) electroless nickel. Typical Application Circuits Typical Low-Power Transmitter Application +9VDC Modulation Input 200k Ω 47 C1 L1 (Antenna) C2 ROXXXXA Bottom View Millimeters RF Bypass Min 470 Typical Local Oscillator Application Output +VDC C1 ROXXXXA Bottom View Inches Dimensions +VDC L1 RF Monolithics, Inc. Phone: (972) 233-2903 Fax: (972) 387-9148 RFM Europe Phone: 44 1963 251383 Fax: 44 1963 251510 ©1999 by RF Monolithics, Inc. The stylized RFM logo are registered trademarks of RF Monolithics, Inc. Max 0.235 B 3.94 0.155 C 2.16 0.085 D 0.94 1.10 0.037 0.043 E 0.83 1.20 0.033 0.047 F 1.16 1.53 0.046 0.060 G 0.94 1.10 0.037 0.043 H 0.43 0.59 0.017 0.023 K 0.43 0.59 0.017 0.023 N RF Bypass Min 5.97 M C2 Max A P 5.31 0.38 0.64 0.209 0.015 3.28 E-mail: [email protected] http://www.rfm.com RO2081A-061901 0.025 0.129 Page 2 of 2