? rf monolithics, inc. phone: (972) 233-2903 fax: (972) 387-8148 e-mail: info@rfm.com page 1 of 2 rfm europe phone: 44 1963 251383 fax: 44 1963 251510 http://www.rfm.com ?1999 by rf monolithics, inc. the stylized rfm logo are registered trademarks of rf monolithics, inc. ro2156a_RO2156A-1_ro2156a-2 _012202 electrical characteristics characteristic sym notes minimum typical maximum units frequency at +25c nominal frequency ro2156a f c 2,3,4,5 868.875 869.025 mhz RO2156A-1 868.875 869.175 ro2156a-2 868.850 869.050 tolerance from 868.95 mhz ro2156a d f c 75 khz RO2156A-1 -75 +225 ro2156a-2 100 insertion loss il 2,5,6 1.1 2.0 db quality factor unloaded q q u 5,6,7 38,997 50 w loaded q q l 4,000 temperature stability turnover temperature t o 6,7,8 10 25 40 c turnover frequency f o f c khz frequency temperature coefficient ftc 0.032 ppm/c 2 frequency aging absolute value during the first year |fa| 1 <10 ppm/yr dc insulation resistance between any two terminals 5 1.0 m w rf equivalent rlc model motional resistance r m 5, 6, 7, 9 11.4295 w motional inductance l m 81.637 h motional capacitance c m 0.41 ff shunt static capacitance c o 5, 6, 7, 9 2.9 pf test fixture shunt inductance l test 2, 7 11.5679 nh lid symbolization (in addition to lot and/ or date code) 197 ? ideal for european 868.95 mhz transmitters ? very low series resistance ? quartz stability ? surface-mount ceramic case with 21 mm 2 footprint ? complies with directive 2002/95/ec (rohs) the ro2156a 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 transmitters operat- ing at 868.95 mhz. this saw is designed specifically for remote-control and wireless security transmitters operating under etsi-ets 300 220 in europe and under ftz 17 tr 2100 in germany. absolute maximum ratings rating value units cw rf power dissipation +5 dbm dc voltage between terminals 30 vdc case temperature -40 to +85 c soldering temperature (10 seconds / 5 cycles max.) 260 c 868.95 mhz saw resonator ro2156a RO2156A-1 ro2156a-2 caution: electrostatic sensitive device. observe precautions for handling. notes: 1. lifetime (10 year) frequency aging. 2. the center frequency, f c , is measured at the minimum insertion loss point, il min , with the resonator in the 50 w test system (vswr 1.2:1). the shunt inductance, l test , is tuned for parallel resonance with c o at f c . 3. one or more of the following united states patents apply: 4,454,488 and 4,616,197. 4. typically, equipment utilizing this device requires emissions testing and gov- ernment approval, which is the responsibility of the equipment manufacturer. 5. unless noted otherwise, case temperature t c =+25c2c for all specifica- tions. 6. the design, manufacturing process, and specifications of this device are sub- ject to change without notice. 7. derived mathematically from one or more of the following directly measured parameters: f c , il, 3db bandwidth, f c versus t c , and c o . 8. turnover temperature, t o , is the temperature of maximum (or turnover) fre- quency, f o . the nominal frequency at any case temperature, t c , may be cal- culated from: f=f o [1-ftc(t o -t c ) 2 ]. 9. this equivalent rlc model approximates resonator performance near the resonant frequency and is provided for reference only. the capacitance c o is the static (nonmotional) capacitance between the two terminals measured at low frequency (10mhz) with a capacitance meter. the measurement includes parasitic capacitance with ?nc? pads unconnected. case parasitic capacitance is approximately 0.05pf. transducer parallel capacitance can be calculated as: c p ? c o - 0.05pf. sm-2 case
868.95 mhz saw resonator rf monolithics, inc. phone: (972) 233-2903 fax: (972) 387-8148 e-mail: info@rfm.com page 2 of 2 rfm europe phone: 44 1963 251383 fax: 44 1963 251510 http://www.rfm.com ?1999 by rf monolithics, inc. the stylized rfm logo are registered trademarks of rf monolithics, inc. ro2156a_RO2156A-1_ro2156a-2 _012202 electrical connections the saw resonator is bidirectional and may be in- stalled 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 recommend- ed to help reduce parasitic capacitance in the cir- cuit. typical test circuit the test circuit inductor, l test , is tuned to resonate with the static capaci- tance, c o , at f c . typical application circuits equivalent lc mode l temperature characteristics the curve shown on the right accounts for resonator contri- bution only and does not in- clude lc component tempera- ture contributions . typical circuit board land pattern the circuit board land pattern shown below is one possible design. the op- timum 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 mini- mize parasitic series inductances. case design the case material is black alumina with contrasting symbolization. all pads are nominally centered with respect to the base and consist of 40 to 70 microinches electroless gold on 60-350 micorinches electroless nickel. nc nc terminal terminal from 50 w network analyzer network analyzer to 50 w electrical test +9vdc 47 rf bypass l1 (antenna) c1 c2 200k w modulation input roxxxxa bottom view 470 typical low-power transmitter application rf bypass l1 c1 c2 roxxxxa bottom view typical local oscillator application +vdc +vdc output dimensions millimeters inches min max min max a 5.74 5.99 0.226 0.236 b 3.73 3.99 0.147 0.157 c 1.91 2.16 0.075 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 m 5.08 5.33 0.200 0.210 n 0.38 0.64 0.015 0.025 p 3.05 3.30 0.120 0.130 0.05 pf* 0.05 pf c p c o + = *case parasitics c p rm lm cm -80 -60 -40 -20 0 +20 +40 +60 0 -50 -100 -150 +80 -200 0 -50 -100 -150 -200 f c = f o , t c = t o d t = t c - t o ( c ) (f-f o o ) / f (ppm) typical dimension: 0.010 to 0.047 inch (0.25 to 1.20 mm) (4 places)
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