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MAQRF112 a utomotive , 300 mhz to 450mhz, +10dbm, 1.8 v to 3.6v, ask/fsk transmitter with shutdown micrel inc. ? 2180 fortune drive ? san jose, ca 95131 ? usa ? tel +1 (408) 944 - 0800 ? fax + 1 (408) 474 - 1000 ? http://www.micrel.com february 7 , 201 3 revision 1.0 general description the MAQRF112 is a high - performance, easy to u se, true ?data - in, r f - out?, ask / fsk, phase - locked loop ( pll ) based, t ransmitter ic for automotive applications in the 300mhz to 450mhz frequency range. these applications include remote k eyle ss entry (rke) and t ire pressure m onitoring systems (tpms) . the device needs only a low - cost crystal to precisely set the desired rf frequency, and a few external components for matching the power amplifier output to the antenna. the MAQRF112 operates over the 1.8v to 3.6v operating range . it delivers +10dbm (cw) output power into a 50 load, while consuming 1 1.5 ma of supply current from a 3. 0 v power supply. in ask mode, the device consumes 6. 9 ma of supply current at a data rate of 1 k bps (manchester 50%) . i t features a low - power shutdown mode in which the device typically consumes 50na of supply current . this makes it an ideal solution for battery powered application s. the MAQRF112 is automotive qualified (aec - q100) and is rated to operate over the ? 40c to +12 5c temperature range. for non - a utomotive applications that do not require aec - q100 qualification, consider the micrf112. for ask - only applications that do not require shutdown, consider the micrf113 in sot23 - 6. datasheets and support documentation a re available on micrel?s web site at: www.micrel.com . features ? aec - q100 automotive q ualified ? 300mhz to 450mhz frequency r ange ? d ata rates up to 50 k bps ask/10 k bps fsk ? 1.8v to 3.6v o perating v oltage r ange ? +10dbm output p ower (cw) at 3.0v ? 11. 5 ma of supply current at +10dbm (cw) ? 6. 9 ma of supply current at 1 k bps (ask, manchester) ? 50na supply current in shutdown mode ? needs only one crystal to set the desired rf frequency ? ? 40 ?c to +125?c o perating temperature r ange ? 10- pin msop p ackage (4.9mm x 3.0mm) applications ? remote k eyless entry s ystems (rke) ? tire p ressure m onitoring s ystems (tpms) ordering information part number temp. range package MAQRF112ymm ? 40c to +125c 10-pi n msop typical application
micrel, inc. MAQRF112 febr uary 7 , 201 3 2 revision 1.0 pin configuration 10- pin msop (ymm) pin description pin number pin name pin function 1 ask ask data input and pa enable. when en is set to a logic - level high and ask is set to a logic - level high, the power amplifier (pa) is enabled. a logic - level low on ask disables the power amplifier. a pply a data stream less than 50k bps (manchester encoded, 50% duty - cycle) for ask modulation. to transmit with fsk modulation, both en and ask need to be set to a logic - level high , whi le the fsk pin is modulated. 2 xtlin reference o scillator i nput c onnection. connect a crystal between xtlin and xtlout. connect a load capacitor from xtlin to ground, based on the recommendations of the crystal manufacturer. 3 xtlout reference o scilla tor o utput c onnection. connect a crystal between xtlin and xtlout. connect a load capacitor from xtl out to ground, based on the recommendations of the crystal manufacturer. 4 vss ground . 5 xtal_mod fsk crystal p ulling switch c onnection. for fsk modula tion, connect a capacitor between the x tal_mod pin and xtlout. for ask - only operation, this pin can be left unconnected. 6 fsk fsk data input. a logic - level low opens the fsk cry stal pulling switch, providing high impedance (>1m ) between the xtal_mod pi n and vss (g round). a logic - level hig h closes the switch, providing low impedance (15 ) between xtal_mod and vss (ground) . this parallels the crystal pulling capacitor, c fsk , with the crystal load capacitor, c load , and pull s the reference frequency to achi eve fsk modulation. for ask - only operation, pulling this pin low is recommended . 7 en enable/shutdown input. a logic - level low disables the entire device, placing it in a low - power shutdown mode. a logic - level high enables the crystal oscillator, pll, vo ltage - controlled oscillator ( vco ), and control blocks, if t he supply voltage is above the undervoltage lockout (uvlo) voltage. the p ower a mplifier is enabled when a logic - level high is applied to en and ask. 8 vsspa power amplifier ground. 9 paout open collector of power amplifier output. pull the pa_out pin to vdd through an inductor to properly bias the output stage. add a pull - up resistor in series to reduce bias current and to achieve lower output power and lower supply current operation. a matching network is required to match the output to desired load (pcb antenna, wire antenna , or 50 load) to achieve best output power, supply current , and spectral performance. see the ?applications information? section f or recommended power supply bypassing. 10 vdd power supply for crystal oscillator, phase -l ocked l oop, voltage - controlled oscillato r, and c ontrol b locks. see the ?applications information? section f or recommended power supply bypassing.
micrel, inc. MAQRF112 febr uary 7 , 201 3 3 revision 1.0 absolute maximum ratings (1) supply voltage ( v vdd ) ................................................. +4.3v voltage on paout ( v paout ) ........................................ +7.2v logic inputs (v ask , v fsk , v en ) ....... v vss ? 0.3 to v vdd + 0.3v st orage temperature range ................... ? 65c to + 150c lead temperature (soldering, 10 s ) .......................... +260c esd rating ................................................................. note 3 operating ratings (2) supply voltage ( v vdd , v paout )??????+1.8v to +3.6v input voltage (v ask , v fsk , v en )?.........................0v to v vdd junction tempera ture (t j ) ........................ ? 40c to +125c transmitter frequency range (f rf ) ...... 300mhz to 450mhz thermal resistance, ( ja )??????????.130 c/w electrical characteristics (4) v vdd = 3.0v, t a = +25c, f refosc = 9.84375mhz for 315mhz, f refosc = 13.560mhz for 433.92mhz , ask = en = vdd. micrf/MAQRF112 50 evaluation board . bold values indicate t a = ? 40c to +125c unless otherwise noted. 1 k bps data rate , 50% duty cycle, pulse width = 500 s . parameter condition min typ max units power supply standby supply current v vdd = 3.6v, v en = 0v 0 .05 3 a mark supply current f rf = 315mhz v vdd = v ask = 3.0v 11.5 ma v vdd = v ask = 3.6v 12.1 14.5 ma f rf = 433.92mhz v vdd = v ask = 3.0v 11.6 ma v vdd = v ask = 3.6v 12.1 15.0 ma space supply current f rf = 315mhz v vdd = 3.0v, v ask = 0v 2.4 ma v vdd = 3.6v, v ask = 0v 2.5 3.5 ma f rf = 433.92mhz v vdd = 3.0v, v ask = 0v 2.7 ma v vdd = 3.6v, v ask = 0v 2.8 3.8 ma ask modulated supply current f rf = 315mhz v vdd = 3.0v, v ask = 1khz 6.9 ma f rf = 433.92mhz v vdd = 3.0v, v ask = 1khz 7.2 ma rf output section and modulation limits output power l evel v ask = 3.0v f rf = 315mhz 5 10 dbm f rf = 433.92mhz 6 10 dbm harmonic output f rf = 315mhz f harmonic = 630mhz ? 53 dbc f harmonic = 945mhz ? 53 dbc f rf = 433.92mh z f harmo nic = 867.84mhz ? 51 dbc f harmonic = 1301.76mhz ? 65 dbc extinction r atio for ask f rf = 315mhz 80 dbc f rf = 433.92mhz 90 dbc fsk modulation maximum data rate manchester encoded (50% duty cycle) ( 4 ) 10 kbps maximum frequency deviation cryst al = hc49/us, load c apacitor = 10pf (4) 25 khz xtal_mod to vss impedance, rdson fsk = vss 1 m fsk = vdd 15 35 ask modulation maximum data rate manchester encoded (50% duty cycle) 50 k bps
micrel, inc. MAQRF112 febr uary 7 , 201 3 4 revision 1.0 parameter condition min typ max units occupied bandwidth f rf = 315mhz ( 5 ) 630 khz f r f = 433.92mhz (5) 670 khz vco section single side - band phase noise f rf = 315mhz f offset = 100khz ? 76 dbc/hz f offset = 1000khz ? 79 dbc/hz f rf = 433.92mhz f offset = 100khz ? 72 dbc/hz f offset = 1000khz ? 81 dbc/hz reference oscillator se ction xtlin, xtlout, xtlmod pin c apacitance 2 pf oscillator start -u p time crystal: hc49s, note 4 400 s digital/control section digital input threshold voltage (en, ask , and fsk) high (v ih ) 0.8v dd v low (v il ) 0.2v dd v digital input current (en, ask , and fsk) high (i ih ), v dd = 3.6v 0.05 1 a low (i il ), v dd = 3.6v 0.05 1 a supp ly underv oltage lock out (uvlo) 1.6 v notes: 1. exceeding the absolute maximum rating s can damage the device. 2. the device is not guaranteed to function outside its operating rating s . 3. devices are esd sensitive. handling precautions are recommended. human body model, 1.5k in series with 100pf. 4. dependent on crystal . 5. rbw = 100khz, obw measured at ? 20dbc. 6. data r ate = 50 k bps, p uls e w idth = 10s, p ulse r epetition t ime = 20s.
micrel, inc. MAQRF112 febr uary 7 , 201 3 5 revision 1.0 typical characteristics (MAQRF112 , 50 evaluation board , v vdd = 3.0 v, v ask = v en = vdd, t a = +2 5 c unless otherwise noted ) 8.0 8.5 9.0 9.5 10.0 10.5 11.0 11.5 12.0 1.8 2.1 2.4 2.7 3.0 3.3 3.6 supply current (ma) supply voltage (v) supply current vs. supply voltage f rf = 315mhz, v ask = vdd t a = - 40?c t a = +125?c t a = +25?c 2.1 2.2 2.3 2.4 2.5 2.6 1.8 2.1 2.4 2.7 3.0 3.3 3.6 supply current (ma) supply voltage (v) supply current vs. supply voltage f rf = 315mhz, v ask = gnd t a = - 40?c t a = +25?c t a = +125?c 5.0 5.5 6.0 6.5 7.0 7.5 1.8 2.1 2.4 2.7 3.0 3.3 3.6 supply current (ma) supply voltage (v) ask modulated supply current vs. supply voltage f rf = 315mhz, v ask = 1kbps (50%) t a = - 40?c t a = +125?c t a = +25?c 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0 1.8 2.1 2.4 2.7 3.0 3.3 3.6 output power (dbm) supply voltage (v) output power vs. supply voltage f rf = 315mhz, v ask = vdd t a = +125?c t a = - 40?c t a = +25?c -55 -50 -45 -40 1.8 2.1 2.4 2.7 3.0 3.3 3.6 2nd harmonic suppression (dbc) supply voltage (v) 2nd harmonic vs. supply voltage f rf = 315mhz, v ask = vdd t a = +125?c t a = +25?c t a = - 40?c -56 -55 -54 -53 -52 -51 -50 1.8 2.1 2.4 2.7 3.0 3.3 3.6 3rd harmonic suppression (dbc) supply voltage (v) 3rd harmonic vs. supply voltage f rf = 315mhz, v ask = vdd t a = +125?c t a = +25?c t a = - 40?c 5 6 7 8 9 10 11 12 13 -4 -2 0 2 4 6 8 10 12 0 100 200 300 400 500 600 700 800 900 1000 supply current (ma) output power (dbm) r bias ( ) output power and supply current vs. r bias f rf = 315mhz, v ask = vdd output power supply current output power supply current
micrel, inc. MAQRF112 febr uary 7 , 201 3 6 revision 1.0 typical characteristics (continued) 8.5 9.0 9.5 10.0 10.5 11.0 11.5 12.0 12.5 1.8 2.1 2.4 2.7 3.0 3.3 3.6 supply current (ma) supply voltage (v) supply current vs. supply voltage f rf = 433.92mhz, v ask = vdd t a = - 40?c t a = +25?c t a = +125?c 2.4 2.5 2.6 2.7 2.8 2.9 1.8 2.1 2.4 2.7 3.0 3.3 3.6 supply current (ma) supply voltage (v) supply current vs. supply voltage f rf = 433.92mhz, v ask = gnd t a = - 40?c t a = +25?c t a = +125?c 5.5 6.0 6.5 7.0 7.5 1.8 2.1 2.4 2.7 3.0 3.3 3.6 supply current (ma) supply voltage (v) supply current vs. supply voltage f rf = 433mhz, v ask = 1kbps (50%) t a = - 40?c t a = +25?c t a = +125?c 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 10.0 10.5 11.0 1.8 2.1 2.4 2.7 3.0 3.3 3.6 output power (dbm) supply voltage (v) output power vs. supply voltage f rf = 433.92mhz, v ask = vdd t a = +25?c t a = - 40?c t a = +25?c -60 -55 -50 -45 1.8 2.1 2.4 2.7 3.0 3.3 3.6 2nd harmonic suppression (dbc) supply voltage (v) 2nd harmonic vs. supply voltage f rf = 433mhz, v ask = vdd t a = +125?c t a = - 40?c t a = +25?c -75 -70 -65 -60 -55 1.8 2.1 2.4 2.7 3.0 3.3 3.6 3rd harmonic suppression (dbc) supply voltage (v) 3rd harmonic vs. supply voltage f rf = 433.92mhz, v ask = vdd t a = - 40?c t a = +125?c t a = +25?c 5 6 7 8 9 10 11 12 13 -4 -2 0 2 4 6 8 10 12 0 100 200 300 400 500 600 700 800 900 1000 supply current (ma) output power (dbm) r bias (?) output power and supply current vs. r bias f rf = 433.92mhz, v ask = vdd (mark) supply current output power
micrel, inc. MAQRF112 febr uary 7 , 201 3 7 revision 1.0 functional diagram figure 1. functional block diagram MAQRF112 functional description the MAQRF112 is a 1.8v to 3.6v, 300 mhz to 450mhz, +10dbm as k/fsk transmitter . it has an integrated crystal oscillator, phase - locked loop (pll), voltage - controlled oscillator (vc o), power amplifier (pa), under voltage lockout (uvlo) and three logic - level inputs for ask modulation/pa enable, fsk modulation , and on/of f control. the device requires only a crystal, crystal loading capacitors, supply bypassing capacitors , and a few output matching components to match the pa to the load (loop antenna, 50 load, or whip antenna). the device achieves ask modulation using on and off modulation of the power amplifier. fsk modulation is achieved by pulling the crystal oscillator when an on - chip switch shunts an additional capacitance across the crystal. the MAQRF112 is enabled or placed into a low - power shutdown mode through t he logic - level en input. an undervoltage lockout disables the pa until the power supply has reached a valid operating range. the only external components required are a crystal, antenna matching components , and power supply bypassing. figure 1 shows the b lock diagram of the MAQRF112. phase - locked loop (pll) synthesizer the pll of the MAQRF112 integrates a vco, a ?divide - by - 32? frequency divider, a phase - frequency detector (pfd), a charge pump, and a loop - filter. the vco tunes from 300 mhz to 450mhz and dr ives both the pa and the divider. the divider divides the vco frequency by 32, and the pfd compares the divided frequency against the reference frequency generated by the crystal oscillator. any phase difference between these signals generates a current in to the loop filter , which closes the loop with the vco providing a precise, low phase - noise vco, with quick start - up time. the pll also includes an internal lock indicator which will keep the pa disabled until the pll has locked.
micrel, inc. MAQRF112 febr uary 7 , 201 3 8 revision 1.0 crystal oscillator the crystal oscillator provides a precision reference frequency to the pll. the MAQRF112 u s es a pierce oscillator, which is operated in parallel resonant mode. it is designed to accept fundamental mode crystals, which operate from 9.375mhz to 14.0625mhz , to ac commodate the ?divide - by - 32? divider of the pll. the crystal frequency is : f xtal = f rf 32 eq. 1 most applications require an initial frequency tolerance of < 30ppm at t a = +25 c and an over temperature stability of 25ppm to 50ppm, but that can vary de pending on the desired operating temperature range and performance required versus crystal cost. the MAQRF112 pierce oscillator can work with values of e quivalent s eries r esistance ( esr ) in the range of 5 to 300 . ask crystal oscillator operation figure 2 shows a reference oscillator circuit con?guration for ask operation. the crystal is placed between the xtlin (pin 2) and xtlout (pin 3). table 1 shows corresponding esr values to crystal parameter valu es. c par is the parallel capacitance determined from internal crystal substrate contacts and board parasitic capacitance. figure 2 . reference oscillator ask operation esr ( ) c par (pf) c mo (ff) c l oad (pf) 20 1 to 10 10 to 40 10 to 70 300 1 to 5 10 to 40 10 to 30 table 1. recommended crystal oscillator values refer ring to figure 2, equation 2 is an example of c l1 and c l2 calculation for a crystal load capacitance, c load = 10pf. the load capacitance seen by the crystal is calculated as follows: stray 2 l 1 l load c c 1 c 1 1 c + + = eq. 2 therefore , the calculation of c l1 and c l2 for a specified c load of 10 pf is a s follows: c stray = 1 .5 pf (stray pin and pcb capacitance) c l1 = c l2 = (c load ? c stray ) 2 c l1 = c l2 = 18pf t he final value of c l1 and c l2 may need to be optimized on the bench because of board stray parasitics . c apacitors , c l1 and c l2 , are placed from xtlin to ground and from xtlout to ground. when specifying a crystal to a crystal manufacture r, the load capacitance, c load , must be specified as part of the manufacturing crystal design. for ask - only operation , connect the fsk pin to vss and leave xtal _ mod unconnected.
micrel, inc. MAQRF112 febr uary 7 , 201 3 9 revision 1.0 fsk operation figure 3 shows the reference oscillator circuit configuration for fsk operation. to operate the MAQRF112 device in fsk mode, one additional capacitor , c fsk , is needed between the xtlout pin and the xtal _ mod pin. crystal parameters for fsk operation are the same as for ask operation except: ? when the esr of the crystal is at 20 , c fsk + c load must not exceed 70pf. ? wh en the esr of the crystal is at 300 , c fsk + c load must not exceed 30pf . figure 3 . reference oscillator fsk operation c l1 , c l2 and c fsk calculation refer ring to figure 3, c l1 , c l2 , and c fsk values depend on c load . capacitor calculation is similar to ask operation, with the addition of a shunt capacitor, c fsk . selection of c l1 , c l2 , and c fsk determine rf c enter frequency, high - side, and l ow - side rf frequency . s ee figure 4. use equation 3 t o calculate the fsk h igh - s ide f requency c alculation . stray 2 l 1 l load c c 1 c 1 1 c + + = eq. 3 use equation 4 to calculate the fsk low - side frequency calculation. stray fsk 2 l 1 l load c c c 1 c 1 1 c + + + = eq. 4 figure 4. MAQRF112 frequency deviation fsk modulation is achieved by pulling the crystal at the desired data rate. pulling the crys tal frequency is done by shunting c fsk with c l2 . a logic - level low on the fsk data input opens the internal switch , removing c fsk , which pulls the reference oscillator high. a logic - level high closes the switch, paralleling the crystal c fsk with c l2 , which pull s the refe rence frequency low. see figure 4. r s is used to minimize cr ystal rf spurs when using a low - quality crystal. a typical value of r s is 0 to 1000 and depends on the crystal chosen . board - level optimization is required to optimize for frequency deviation and occupied bandwidth requirements.
micrel, inc. MAQRF112 febr uary 7 , 201 3 10 revision 1.0 power amplifier the power amplifier serves two purposes: t o buffer the vco from external elements and to a mplify the phase - locked signal . the power amplifier can produce +10dbm at 3v (typical). the pa output matching network to a 50 load or to a pc b antenna serves two purposes: to o ptimize pa output power and to m inimize unwanted harmonics. matching values are a function of operational frequency and load impedance seen by the MAQRF112. the ?application information? s ection provides matching values for 315mhz and 433.92mhz. power control using an external resistor a resistor (r7 on the 50 evaluation board) is in series with the output rf choke and can be used to adjust the rf output power and supply current . this adjustment can also be used to lower the power to meet fcc compliance. see the ? output power and supply current vs. r bias ? graphs in the ? t ypical characteristics ? section for examples of performance on the 50 evaluation boards. an e valuation board using a pcb antenna can have its radiated power lowered by adjusting this series resistor. the resistor value must be calibrated empirically, and will vary depending on the final product pcb layout and form factor. enable control the e nable control gates the ask data to the pa. it allows transmission only when the l ock, crystal amplitude , and undervoltage d etect conditions are valid. an enable and ask logic - level high places the pa in the mark condition . an e nable lo gic - level low disables the p ower amplifier. an e nable logic - level high and an ask logic - level low places the pa in the space condition. to transmit with fsk modulation , both the en and ask pin s must be set to a logic - level high while the fsk pin is digital ly modulated with a logic - level signal. ask input control an ask logic - level data input modulates the rf carrier when the pa is enabled. a pply a data stream less than 50k bps (manchester encoded, 50% duty - cycle) for ask modulation. tying the fsk pin low i s recommended when ask modulation is used. underv oltage detect the u nder voltage detect bloc k senses the operating voltage. if the operating v oltage falls below 1.6v, the under voltage detect block send s a signal to the enable control block to disable the p a.
micrel, inc. MAQRF112 febr uary 7 , 201 3 11 revision 1.0 application information the MAQRF112 is ideal for driv ing a 50 load monopole or a pcb loop antenna. the following sections discuss pcb l oop antenna and 50 output configurations. output matching network part of the function of the output network is to attenuate the second and third harmonics. when matching to a transmit frequency, take care not only to optimize for maximum output power but to attenuate unwanted harmonics. proper matching to a pcb antenna or a 50 ? load optimize s current requirements. layout issues pcb l ayout is extremely important to achieve optimum performance and con sistent manufacturing results. be careful with the orientation of the components to ensure that they do not cou ple or decouple the rf signal. pcb trace length should be s hort , to minimize parasitic inductance (1in ~ 20nh). for example, depending on inductance values, a 0.5 in trace can change the inductance by as much as 10%. to reduce parasitic inductance, the use of wide traces and a ground plane under signal traces is re commended. use v ias with low inductance value s for components requiring a connection to ground. crystal pcb layout crystal pcb board layout a ffect s the calculated frequency deviation. i t is recommended that the crystal be located close to the xtlin and xt lout pins to minimize trace lengths. trace thickness should be no greater th a n 20mil. antenna layout the a ntenna trace layout affects d irectivity. no ground plane should be under the antenna trace. for consistent performance, do not place components insid e the loop of the antenna. gerbers for a suggested layout are available on the micrel website at: www.micrel.com . ask pcb loop antenna application circuit figure 5 is an example of a n ask circuit configuration using a pcb loop antenna. table 2 lists modified values for both 315mhz and 433.92mhz configurations , including crystal values for 315mhz and 433.92mhz operation. values are dependent on pcb board layout. refer to the micrel website for a reference design and pcb gerber files. frequency (mhz) l1 (nh) c5 (pf) l4 (nh) c7 (pf) y1 (mhz) 315 470 10 150 4.7 9.84375 433.92 680 10 82 3.9 13.5600 table 2. pcb antenna matching network figure 5 . MAQRF112 ask application circuit with pcb loop antenna
micrel, inc. MAQRF112 febr uary 7 , 201 3 12 revision 1.0 fsk pcb loop antenna application circuit figure 6 is an example of a fsk circuit configuration using a pcb loop antenna. table 3 lists modified values for both 315mhz and 433.92mhz configurations , including crystal values for 315mhz and 433.92mhz operat ion. antenna matching values are dependent on pcb board layout. refer to the micrel website for a reference design and pcb gerber files. table 4 list s crystal capacitor load values for a frequency deviation of 25khz. for crystal capacitor calculations , re fer to the ? fsk operation ? section . frequency (mhz) l1 (nh) c5 (pf) l4 (nh) c7 (pf) y1 (mhz) 315 470 10 150 4.7 9.84375 (1) 433.92 680 10 82 3.9 13.5600 (2) table 3. pcb antenna matching network notes: 1. y1 = abracon abls - 9.84375mhz - 10- r50 - k4q f or 315mhz 2. y1 = abracon abls - 13.5600mhz - 10- r50 - k4q for 433.92mhz center frequency (mhz) c14 (pf) c13 (pf) c8 (pf) frequency deviation (khz) 315 15 10 22 25 433.92 18 6.8 15 25 table 4. crystal capacitor values for fsk operation figure 6 . m aqrf112 fsk application circuit with pcb loop antenna
micrel, inc. MAQRF112 febr uary 7 , 201 3 13 revision 1.0 ask 50 ? load application circuit figure 7 is an example of a n ask circuit configuration used to drive a 50 load. table 5 lists modified values for both 315mhz and 433.92mhz configurations , including crystal values for 315mhz and 433.92mhz operation. the matchin g network values are dependent on pcb board layout. refer to the micrel website for a reference design and the pcb gerber files frequency (mhz) l1 (nh) c5 (pf) l2 (nh) c7 (pf) c11 (pf) y1 (mhz) 315 470 8.2 82 8.2 2.2 9.84375 433.92 470 2.2 82 6.8 1.2 13. 5600 table 5. 50 ? load matching network figure 7 . MAQRF112 ask 50 ? evaluation board
micrel, inc. MAQRF112 febr uary 7 , 201 3 14 revision 1.0 fsk - 50 load application circuit figure 8 is an example of a fsk circuit conf iguration used to drive a 50 load. table 6 lists modified values for both 315mhz and 433.92mhz conf igurations , including crystal values for 315mhz and 433.92mhz operation. the matching network values are dependent on pcb board layout. refer to the micrel web site for a reference design and pcb gerber files. table 7 list s crystal capacitor load values for a frequency deviation of 25 khz. for crystal capacitor calculations , refer to the ? fsk operation ? section . frequency (mhz) l1 (nh) c5 (pf) l2 (nh) c7 (pf) c11 (pf) y1 (mhz) 315 470 8.2 82 8.2 2.2 9.84375 (1) 433.92 470 2.2 82 6.8 1.2 13.5600 (2) table 6. 50? load matching network notes: 1. y1 = abracon abls - 9.84375mhz - 10- r50 - k4q for 315mhz 2. y1 = abracon abls - 13.5600mhz - 10- r50 - k4q for 433.92mhz center frequency (mhz) c17 (pf) c18 (pf) c9 (pf) frequency deviation (khz) 315 15 10 22 25 433.92 18 6.8 15 25 table 7. 50? load matching network figure 8 . MAQRF112 fsk 50 ? evaluation board
micrel, inc. MAQRF112 febr uary 7 , 201 3 15 revision 1.0 p ackage information (1) 10- pin msop package type (ymm) note: 1. package information is correct as of the publication date. for updates and most current information, go to www.micrel.com . micrel, inc. 2180 f ortune drive san jose, ca 95131 usa tel +1 (408) 944 - 0800 fax +1 (408) 474 - 1000 web http://www.micrel.com micrel makes no representations or warranties with respect to the accuracy or completeness of the info rmation furnished in this datasheet. this information is not intended as a warranty and micrel does not assume responsibility for its use. micrel rese rves the right to change circuitry, specifications and descriptions at any time without notice. no license, whether express, implied, arising by estoppel or otherwise, to any intellectual property rights is granted by this document. except as provided in micrel?s terms and conditions of sale for such products, micrel assumes no liability whatsoever, and micrel disclaims any express or implied warranty relating to the sale and/or use of micrel products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right . micrel products are not designed or authorized for use as components in life support appliances, devices or systems where mal function of a product can reasonably be expected to result in personal injury. life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reaso nably expected to result in a significant injury to the user. a purchaser?s use or sale of micrel products for use in life support appliances, devices or systems is a purchaser?s own risk a nd purchaser agrees to fully indemnify micrel for any damages resul ting from such use or sale. ? 20 13 micrel, incorporated.

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