data bulletin MX315A ctcss encoder 1998 mx com, inc. www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054 doc. # 20480054.006 4800 bethania station road, winston-salem, nc 27105-1201 usa all trademarks and service marks are held by there respective compa nies. features applications field programmable tone encoder 40 ctcss frequencies crystal-controlled frequency stability low distortion sinewave output few external components required cmos low power requirements mobile radio base stations & repeater stations mobile radios hand-held radios industrial controls intercom systems door-entry systems xtal/clock clock generator d0-d5 xtal binary rate multiplier tx enable tx enable v dd programmed clocks tx tone square wave tx tone sinewave output emitter follower enable tx tone output the MX315A is a monolithic cmos tone encoder for sub-audible tone squelch systems, which provides three additional frequencies over the earlier MX315A. these frequencies are 69.3, 97.4 and 206.5hz. the tone frequencies are derived from an input reference frequency. an on-chip inverter is provided to drive an external crystal circuit. tone selection is achieved through six programming inputs and two control inputs (which allow either a logic 1 or 0 to enable the device). a low distortion sinewave is generated at the tx tone output when the MX315A is enabled. the emitter follower output stage can source 1mw directly into a 600 load (0dbm). the MX315A is available in the following package styles: 16-pin soic (MX315Adw), 14-pin pdip (MX315Ap) and 14-pin cdip (MX315Aj).
ctcss encoder 2 MX315A 1998 mx com, inc. www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054 doc. # 20480054.006 4800 bethania station road, winston-salem, nc 27105-1201 usa all trademarks and service marks are held by there respective compa nies. contents section page 1. block diagram................................................................................................................ 3 2. signal list.................................................................................................................. ..... 4 3. external components.................................................................................................... 5 4. application .................................................................................................................. ... 6 4.1 interfacing and electromagnetic capability ......................................................................... 6 4.2 ctcss programming.......................................................................................................... 7 5. performance specification............................................................................................ 8 5.1 electrical performance ...................................................................................................... .. 8 5.1.1 absolute maximum ratings.................................................................................................. .. 8 5.1.2 operating limits .......................................................................................................... ........... 8 5.1.3 operating characteristics................................................................................................. ...... 8 5.2 packaging................................................................................................................... ......... 9 mx?com, inc. reserves the right to change specifications at any time and without notice.
ctcss encoder 3 MX315A 1998 mx com, inc. www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054 doc. # 20480054.006 4800 bethania station road, winston-salem, nc 27105-1201 usa all trademarks and service marks are held by there respective compa nies. 1. block diagram xtal/clock clock generator d0-d5 xtal binary rate multiplier tx enable tx enable v dd programmed clocks tx tone square wave tx tone sinewave output emitter follower enable tx tone output figure 1: device block diagram
ctcss encoder 4 MX315A 1998 mx com, inc. www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054 doc. # 20480054.006 4800 bethania station road, winston-salem, nc 27105-1201 usa all trademarks and service marks are held by there respective compa nies. 2. signal list pins signal j,p dw name type description 1 1 d3 input 2 2 d2 input 3 3 d1 input 4 4 d0 input 5 5 d4 input 6 6 d5 input d0-d5 are tone select inputs with internal pull-up resistors. the logic combination at these inputs determines the encoded ctcss tone. see table 1. the input sequence is not latched and may be changed at any time. a logic 1 will be programmed if the input is open circuit, allowing the use of spst switches. 77 v ss power negative supply voltage. 8 8 xtal/clock in input this is the input to the cmos inverter. it can be used in conjunction with the xtal output to form the active element in a crystal oscillator circuit. alternatively, a logic level 1mhz frequency can be injected at this pin. however, the supply voltage should never be applied without the input clock signal. 99 xtal output output this is the output of the cmos inverter. when used as a crystal oscillator, track lengths and loading of this pin should be minimized. 10 10 internal connection do not use 11 n/c no connection 12 n/c no connection 11 13 tx tone output output this is the tone output pin. it includes a low impedance emitter follower stage for sourcing sinusoidal tone. the tone is generated about a dc level of approximately v dd /2. the pin is high impedance when not encoding. 12 14 tx enable input input this logic input has an internal pull-up resistor. a logic 0 at this pin enables the MX315A. 13 15 tx enable input input this logic input has an internal pull-down resistor. a logic 1 at this pin enables the MX315A. 14 16 v dd power positive supply voltage. table 1: signal list
ctcss encoder 5 MX315A 1998 mx com, inc. www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054 doc. # 20480054.006 4800 bethania station road, winston-salem, nc 27105-1201 usa all trademarks and service marks are held by there respective compa nies. 3. external components microphone voice band filter summing amplifier to modulator tx tone out x1 1mhz 1m 33pf ptt 12 9 8 xtal/clock tx enable xtal 4 3 215 6 11 d0 d1 d2 d3 d4 d5 v ss MX315Aj figure 2: external components r1 note 1 1m 20% c1 33pf 20% x1 note 2, 3 1mhz 0.19% table 2: recommended external components notes: 1. the 1m resistor is used to bias the internal cmos inverter into its linear mode. a tolerance of 20% is acceptable. 2. x1 is a parallel resonant crystal. a reference frequency of 1mhz 0.19% is required to maintain a tone accuracy within 0.5%. 3. for best results, a crystal oscillator design should drive the clock inverter input with signal levels of at least 40% of v dd , peak to peak. tuning fork crystals generally cannot meet this requirement. to obtain crystal oscillator design assistance, consult your crystal manufacturer.
ctcss encoder 6 MX315A 1998 mx com, inc. www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054 doc. # 20480054.006 4800 bethania station road, winston-salem, nc 27105-1201 usa all trademarks and service marks are held by there respective compa nies. 4. application the MX315A is dedicated to continuous tone-controlled squelch systems (ctcss) in radio applications. however, it can be used wherever encoding of low-frequency tones is required, such as intercoms, door-entry systems and various industrial applications. the performance of a ctcss system can be degraded if speech frequencies in the signaling spectrum are not removed prior to transmission. this can be accomplished by filtering the microphone signals to attenuate frequencies below 250 hz. figure 2 illustrates the addition of tx tone output to the filtered microphone signals prior to modulation. figure 3 illustrates the tx tone output sequence and a typical spectral analysis. where two or more circuits are required to use a single oscillator (i.e. repeater applications), the signal at xtal can be used to drive one additional xtal/clock input. any further circuits can be driven from the buffered xtal output of the second device. the program code can be set on the d0-d5 inputs by hardwired logic levels or spst switches to v ss , as illustrated in figure 2 (allowing the internal pull-up resistors to program a logic 1). the MX315A provides both a tx enable input and a tx enable input. either input can be used to enable the tone output, with the unused pin left open circuit (internal resistors establish a valid logic level and prevent damage). any configuration of ptt switch or tx signal can therefore be interfaced. tx enable tx tone output rise-time envelope d.c. ground d.c. ground relative harmonic levels (db) frequency 0 10 20 30 40 50 60 70 fundamental tx tone spectrum f 0 2f 0 3f 0 4f 0 5f 0 6f 0 7f 0 8f 0 figure 3: tone encoding sequence and spectral response 4.1 interfacing and electromagnetic capability the MX315A requires a clock of 1mhz, which is internally converted to logic level square waves. consideration should therefore be given to possible interference problems with rf or if circuitry caused by 1mhz or its harmonics. a decoupling capacitor can be used to reduce ripple on the power supply. this will reduce the level of superimposed noise on the supply caused by internal switching transients (particularly at 1mhz and f 0 ).
ctcss encoder 7 MX315A 1998 mx com, inc. www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054 doc. # 20480054.006 4800 bethania station road, winston-salem, nc 27105-1201 usa all trademarks and service marks are held by there respective compa nies. 4.2 ctcss programming tone programming inputs nominal frequency (hz) MX315A freq. (hz) fo (%) d5 d4 d3 d2 d1 d0 hex 67.0 67.06 +.10 1 1 1 1 1 1 3f 69.3 69.37 +.10 1 1 1 0 0 1 39 71.9 71.84 -.08 0 1 1 1 1 1 1f 74.4 74.33 -.10 1 1 1 1 1 0 3e 77.0 76.99 -.02 0 0 1 1 1 1 0f 79.7 79.65 -.06 1 1 1 1 0 1 3d 82.5 82.50 0.0 0 1 1 1 1 0 1e 85.4 85.34 -0.7 1 1 1 1 0 0 3c 88.5 88.62 +.14 0 0 1 1 1 0 0e 91.5 91.38 -.13 1 1 1 0 1 1 3b 94.8 94.88 +.08 0 1 1 1 0 1 1d 97.4 97.46 +.06 1 1 1 0 1 0 3a 100.0 99.87 -.13 0 0 1 1 0 1 0d 103.5 103.39 -.11 0 1 1 1 0 0 1c 107.2 107.17 -.03 0 0 1 1 0 0 0c 110.9 110.85 -.04 0 1 1 0 1 1 1b 114.8 114.80 0.0 0 0 1 0 1 1 0b 118.8 118.60 -.17 0 1 1 0 1 0 1a 123.0 123.12 +.10 0 0 1 0 1 0 0a 127.3 127.50 +.16 0 1 1 0 0 1 19 131.8 131.67 -.10 0 0 1 0 0 1 09 136.5 136.69 +.14 0 1 1 0 0 0 18 141.3 141.48 +.13 0 0 1 0 0 0 08 146.2 145.96 -.16 0 1 0 1 1 1 17 151.4 151.45 +.03 0 0 0 1 1 1 07 156.7 156.59 -.07 0 1 0 1 1 0 16 162.2 162.10 -.06 0 0 0 1 1 0 06 167.9 168.01 +.07 0 1 0 1 0 1 15 173.8 173.43 -.21 0 0 0 1 0 1 05 179.9 180.21 +.17 0 1 0 1 0 0 14 186.2 186.46 +.14 0 0 0 1 0 0 04 192.8 193.16 +.19 0 1 0 0 1 1 13 203.5 202.88 -.31 0 0 0 0 1 1 03 206.5 206.78 +.14 1 1 1 0 0 0 38 210.7 210.84 +.07 0 1 0 0 1 0 12 218.1 217.96 -.07 0 0 0 0 1 0 02 225.7 225.58 -.05 0 1 0 0 0 1 11 233.6 233.75 +.07 0 0 0 0 0 1 01 241.8 242.54 +.31 0 1 0 0 0 0 10 250.3 250.06 +.10 0 0 0 0 0 0 00 test 4032 0.0 1 1 0 0 1 1 *33 * - or any invalid address table 3: ctcss tones
ctcss encoder 8 MX315A 1998 mx com, inc. www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054 doc. # 20480054.006 4800 bethania station road, winston-salem, nc 27105-1201 usa all trademarks and service marks are held by there respective compa nies. 5. performance specification 5.1 electrical performance 5.1.1 absolute maximum ratings exceeding these maximum ratings can result in damage to the device. general min. max. units supply voltage -0.3 7.0 v j / p /dw packages total allowable device dissipation at t amb = 25c 800 mw derating above 25c 10 mw/c above 25c operating temperature -30 +85 c storage temperature -55 +125 c 5.1.2 operating limits correct operation of the device outside these limits is not implied. notes min. typ. max. units v dd 4.5 5.0 5.5 v operating temperature -30 85 c clock note 1 1 mhz operating limits note: 1. x1 is a parallel resonant crystal. a reference frequency of 1 mhz 0.19% is required to maintain a tone accuracy within 0.5%. 5.1.3 operating characteristics for the following conditions unless otherwise specified: v dd = 5.0v , t amb = 25c, xtal frequency = 1mhz notes min. typ. max units supply current (operating) 1.5 4.5 ma input impedance 1 500 k input impedance 2 10 m logic input 1 3.5 v logic input 0 1.5 v tx output emf 3 550 775 mv rms tx risetime 1 ms tx tone output load current 5 ma tx distortion 3 2 5 % variation in output level between tones 3 0.1 db operating characteristics notes: 1. refers to d0, d1, d2, d3, d4, d5, tx enable and tx enable inputs 2. refers to xtal/clock input 3. any program tone and r l = 600 , c l = 15pf. thd measurements are taken in the 0-6 khz bandwidth.
ctcss encoder 9 MX315A 1998 mx com, inc. www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054 doc. # 20480054.006 4800 bethania station road, winston-salem, nc 27105-1201 usa all trademarks and service marks are held by there respective compa nies. 5.2 packaging pin 1 a b alternative pin location marking x p j y c k h e l t w z note : all dimensions in inches (mm.) angles are in degrees package tolerances a b c e h typ. max. min. dim. j p x w t y k l 0.105 (2.67) 0.093 (2.36) 0.419 (10.64) 45 7 0 10 0.050 (1.27) 0.041 (1.04) 0.413 (10.49) 0.299 (7.59) 0.050 (1.27) 0.016 (0.41) 0.390 (9.90) 0.020 (0.51) 0.003 (0.08) 0.009 (0.23) 0.0125 (0.32) 0.013 (0.33) 0.020 (0.51) 0.395 (10.03) 0.286 (7.26) z 5 5 figure 4: 16-pin soic mechanical outline: order as part no. MX315Adw package tolerances b a pin 1 e y e1 t note : all dimensions in inches (mm.) angles are in degrees a b c e e1 h typ. max. min. dim. j j1 p t y k l 0.200 (5.06) 0.260 (6.60) 0.390 (9.91) 7 0.150 (3.81) 0.810 (20.57) 0.135 (3.43) 0.100 (2.54) 0.121 (3.07) 0.300 (7.62) 0.290 (7.37) 0.325 (8.26) 0.015 (0.38) 0.070 (1.77) 0.015 (0.38) 0.023 (0.58) 0.040 (1.01) 0.065 (1.65) 0.056 (1.42) 0.064 (1.63) 0.740 (18.80) 0.240 (6.10) 0.008 (0.20) 0.015 (0.38) k h j1 j c p l figure 5: 14-pin pdip mechanical outline: order as part no. MX315Ap
ctcss encoder 10 MX315A 1998 mx com, inc. www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054 doc. # 20480054.006 4800 bethania station road, winston-salem, nc 27105-1201 usa all trademarks and service marks are held by there respective compa nies. note : all dimensions in inches (mm.) angles are in degrees package tolerances a b e e1 f h typ. max. min. dim. j p t k1 k l 0.288 (7.32) 0.420 (10.67) 0.200 (5.08) 0.766 (19.46) 0.100 (2.54) 0.115 (2.92) 0.360 (9.14) 0.305 (7.75) 0.315 (8.00) 0.600 (15.24) 0.015 (0.38) 0.018 (0.46) 0.053 (1.35) 0.075 (1.91) 0.080 (2.03) 0.080 (2.03) 0.754 (19.15) 0.240 (6.10) 0.010 (0.254) c 0.165 (4.19) 0.230 (5.84) j1 0.060 (1.52) e1 t e b a pin 1 h k f j k1 p l c j1 figure 6: 14-pin cdip mechanical outline: order as part no. MX315Aj
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