Motorola Mtx Series Detailed Rev 6881088c46 E Manual
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FMR-2045A-2December 26, 2003 UHF Theory of Operation: Synthesizer11 The Frequency Generation Circuitry is composed of two main ICs: Fractional-N synthesizer (U201) VCO/Buffer IC (U241) Designed in conjunction to maximize compatibility, the two ICs provide many of the functions that normally would require additional circuitry. The synthesizer block diagram illustrates the interconnect and support circuitry used in the region. Refer to the relevant schematics for the reference designators. The synthesizer is powered by regulated 5V and 3.3V which come from U247 and U248 respectively. The synthesizer in turn generates a super-filtered 4.5V which powers U241. In addition to the VCO, the synthesizer must interface with the logic and ASFIC circuitry. Programming for the synthesizer is accomplished through the data, clock and chip select lines from the microprocessor. A 3.3V dc signal from the synthesizer lock detect line indicates to the microprocessor that the synthesizer is locked. Transmit modulation from the ASFIC is supplied to pin 10 of U201. Internally the audio is digitized by the Fractional-N and applied to the loop divider to provide the low-port modulation. The audio runs through an internal attenuator for modulation balancing purposes before going out to the VCO. 1.4 Synthesizer (Refer to UHF Synthesizer Schematic Diagram on page 22.) Figure 1-4. Synthesizer Block Diagram The Fractional-N Synthesizer uses a 16.8MHz crystal (FL201) to provide a reference for the system. The LVFractN IC (U201) further divides this to 2.1MHz, 2.225 MHz, and 2.4 MHz as reference frequencies. Together with C206, C207, C208, R204 and CR203, they build up the reference oscillator which is capable of 2.5ppm stability over temperatures of -30 to 85 °C. It also provides 16.8 MHz at pin 19 of U201 to be used by the ASFIC. DATA CLK CEX MODIN V CC, DC5V XTAL1 XTAL2 WARP PREIN VCP REFERENCE OSCILLATOR VOLTAGE MULTIPLIER VOLTAGE CONTROLLED OSCILLATOR 2-POLE LOOP FILTER DATA (U409 PIN 100) CLOCK (U409 PIN 1) CSX (U409 PIN 2) MOD IN (U404 PIN 40) +5V (U247 PIN 4)7 8 9 10 13, 30 23 24 25 32 47 VMULT2 VMULT1BIAS1 SFOUTAUX3 AUX4 IADAPTIOUTGND FREFOUTLOCK4 19 6, 22, 23, 24 43 45 3 2 28 14 1540FILTERED 5VSTEERING LINE LOCK (U409 PIN 56) PRESCALER INLO RF INJECTION TX RF INJECTION (1ST STAGE OF P A FREF (U201 PIN 21 & U404 PIN 34) 39 BIAS2 41 DUAL TRANSIS DUAL TRANSIS-48 5VR5 5, 20, 34, 36 (U248 PIN 5) AUX1 V DD, 3.3VMODOUT U251 LOW VOLTAGE FRACTIONAL-N SYNTHESIZER TORSTORS
December 26, 2003FMR-2045A-2
12UHF Theory of Operation: Voltage-Controlled Oscillator (VCO)
The loop filter which consist of C231, C232, C233, R231, R232 and R233 provides the necessary dc
steering voltage for the VCO and determines the amount of noise and spur passing through.
In achieving fast locking for the synthesizer, an internal adapt charge pump provides higher current
at pin 45 of U201 to put synthesizer within the lock range. The required frequency is then locked by
normal mode charge pump at pin 43.
Both the normal and adapt charge pumps get their supply from the capacitive voltage multiplier
which is made up of C258, C259, C228, triple diode CR201 and level shifters U210 and U211. Two
3.3V square waves (180 degrees out of phase) are first shifted to 5V, then along with regulated 5V,
put through arrays of diodes and capacitors to build up 13.3V at pin 47 of U201.
1.5 Voltage-Controlled Oscillator (VCO)
(Refer to the UHF Voltage-Controlled Oscillator Schematic Diagram on page 23.)
Figure 1-5. VCO Block Diagram
Presc
RX
TXSecond
BufferLow Pass
Filter
Attenuator Pin8
Pin14
Pin10 Level Shifter
Network5V
(U201 Pin28)
VCC Buffers
TX RF Injection U201 Pin 32AUX4 (U201 Pin3)AUX3 (U201 Pin2)
Prescaler Out
Pin 12 Pin 19 Pin 20
TX/RX/BS
Switching Network
U241
VCOBIC
Rx
Active Bias
Tx
Active Bias
Pin2
Rx-I adjustPin1
Tx-I adjustPins 9,11,17
Pin18Vsens
Circuit Pin15Pin16 RX VCO
Circuit
TX VCO
Circuit RX Tank
TX TankPin7
Vcc-Superfilter
Collector/RF in
Pin4
Pin5
Pin6
RX
TX
(U201 Pin28)Rx-SW
Tx-SW
Vcc-Logic
(U201 Pin28) Steer Line
Voltage
(VCTRL)Pin13
Pin3TRB_IN
LO RF INJECTION
VSFVSF VSF
FMR-2045A-2December 26, 2003 UHF Theory of Operation: Voltage-Controlled Oscillator (VCO) 13 The VCOBIC (U241) in conjunction with the Fractional-N synthesizer (U201) generates RF in both the receive and the transmit modes of operation. The TRB line (U241 pin 19) determines which oscillator and buffer will be enabled. A sample of the RF signal from the enabled oscillator is routed from U241 pin 12, through a low pass filter, to the prescaler input (U201 pin 32). After frequency comparison in the synthesizer, a resultant CONTROL VOLTAGE is received at the VCO. This voltage is a dc voltage between 3.5V and 9.5V when the PLL is locked on frequency. The VCOBIC (U241) is operated at 4.54V (VSF) and Fractional-N synthesizer (U201) at 3.3V. This difference in operating voltage requires a level shifter consisting of Q260 and Q261 on the TRB line. The operation logic is shown in Table 1-1. In receive mode, U241 pin 19 is low or grounded. This activates the receive VCO by enabling the receive oscillator and the receive buffer of U241. The RF signal at U241 pin 8 is run through a second buffer to improve mixer to receive VCO isolation. The resulting RF signal is LO RF INJECTION and it is applied to the mixer at T302. (Refer to the UHF Receiver Front-End Schematic Diagram on page 20.) During the transmit condition, when PTT is depressed, a five-volt current is applied to U241 pin 19. This activates the transmit VCO by enabling the transmit oscillator and the transmit buffer of U241. The RF signal at U241 pin 10 is injected into the input of the PA module (U101 pin16). This RF signal is the TX RF INJECTION. Also in transmit mode, the audio signal to be frequency modulated onto the carrier is received through the U201 pin 41. When a high impedance is applied to U241 pin 19, the VCO is operating in BATTERY SAVER mode. In this case, both the receive and transmit oscillators as well as the receive transmit and prescaler buffer are turned off.Table 1-1. Level Shifter Logic Desired Mode AUX 4 AUX 3 TRB TxLowHigh (@3.2V)High (@4.8V) Rx High Low Low Battery SaverLowLowHi-Z/Float (@2.5V)
December 26, 2003FMR-2045A-2 This page intentionally left blank. 14UHF Theory of Operation: Voltage-Controlled Oscillator (VCO)
Chapter 2 UHF Circuit Board Layouts, Schematic Diagrams and Parts List 2.1 Notes for All Schematics and Circuit Boards * Component is frequency sensitive. Refer to the Electrical Parts List for value and usage. 1.Unless otherwise stated, resistances are in Ohms (k = 1000), and capacitances are in picofarads (pF) or microfarads (µF). 2.DC voltages are measured from point indicated to chassis ground using a Motorola DC multimeter or equivalent. Transmitter measurements should be made with a 1.2 µH choke in series with the voltage probe to prevent circuit loading. 3.Reference Designators are assigned in the following manner: 100 Series = Transmitter 200 Series = Frequency Generation 300 Series = Receiver 400/500 Series = Controller 600 Series = Keypad board 4.Interconnect Tie Point Legend: UNSWB+ = Unswitch Battery Voltage (7.5V) SWB+ = Switch Battery Voltage (7.5V) R5 = Receiver 5 Volts CLK = Clock Vdda = Regulated 3.3 Volts (for analog) Vddd = Regulated 3.3 Volts (for digital) CSX = Chip Select Line SYN = Synthesizer DACRX = Digital-to-Analog Voltage (for Receiver Front-End Filter) VSF = Voltage Super Filtered (5 volts) VR = Voltage Regulator SIX-LAYER CIRCUIT BOARD DETAIL VIEWING COPPER STEPS IN PROPER LAYER SEQUENCE LAYER 1 (L1) LAYER 2 (L2) LAYER 3 (L3) LAYER 4 (L4) LAYER 5 (L5) LAYER 6 (L6) INNER LAYERS SIDE 1 SIDE 2
December 26, 2003FMR-2045A-2 This page intentionally left blank. 16UHF Circuit Board Layouts, Schematic Diagrams and Parts List: Notes for All Schematics and Circuit Boards
Circuit Board/Schematic Diagrams and Parts List 17 FMR-2045A-2 December 26, 2003 2.2 Circuit Board/Schematic Diagrams and Parts List Figure 2-1. UHF (403-470MHz) Main Board Top Side PCB No. 8486458Z02 C505 R507 C502 VR5011 23 5PB501 43 2 FL304C521 FL302 VR440 C349 R3652 Y301 4 3 2 FL303 C352 R321 R324R345 R355 R360 C362 R342458 U302C324 C325C338 2 3 4 56 FL301 L311 L330 SH323 C320 C322 C381 L309 L310 R308R309 R310SH303 6 4 3 T30164 3 T302C319 C375R348 TP202TP302 1 23 5PB504 C511C512 C513 C514 C520 43 2CR503 1 2 3 5 PB505 Q502Q505 R501 R502R505 R506 VR443 C140 C141 L116 C101C102 C103 C104 C106 C107 C175CR101 CR102 L101 L102L104 L105 SH100 C301 C302 C303 C304 C305 C308 CR301 CR302 L301L302 R301 R302 SH301 12 3 Q110 C109 C 111C112 L106 C110C113 C114 L107L115 L114 C115 C116 C117 C118 C120 C121 C127 L108L109 R103 R106 R107R108 R175 R176 C119 C171 R104R120 R171 R173R174 C122 C125 C129 C160 C161 C165 C169 L113 R161 1 168 9 U101 C131 C166 SH101L160123 5PB502 1 23 5PB503 B503 B504 6 431 FL201 C432 TP201 C203 C210 C211 C212 C213C214 C217 C220 C228 C229 C230 C233 C235 C238 C257 C260 C291 C292 C294 C297 CR201L201L202 L203 L2324 3Q210 4 3 Q260 R255 R256SH201 U247 C247 C248 C251 C253 C271C272 C273 C276 C285 C286 C289 C370 C374 C386 1 3 L2431 3 L253 L271 L273 L282 L321 Q2414 3 Q261 R243 R248 R253 R260 R333 R339 SH24132 17 161 U4061 40J400 22 21 8 7 1 U405 C423 E407 E408 E409 R410 R418R437 C427 C428 1 45 8 U407 R429 R492 SH400 C424C429 R408R428 R478C425 C426 C402C467 C480 C482 CR440 Q403 43 Q405 R416R447 R448 R451 R452 R453 R454 R455 R456 R481 C401CR412 Q400 R401 R402R405 SH401 TP415 R407 R427 R476 4 5 8U400 C403 C400 C406 R403 R406 4 3 Q417 CR413 TP40622 20121 J403 L400R421 TP405 VR434 VR450 C441 C471C472 C473 C490 C491 C492 C493 C494 C495 C496C497 R477 R450C404 C443 C444L401R435 RT400TP401 TP402 TP410 VR447 VR449
18Circuit Board/Schematic Diagrams and Parts ListDecember 26, 2003FMR-2045A-2 Figure 2-2. UHF (403-470MHz) Main Board Bottom Side PCB No. 8486458Z02 C449 C463 C524 C525 E401E402E403 E404E405 E406 26 1 7651 U409 C453 C456R411 R432 L410 L411 C458 C459 C466C526 C527 C528 C529 E400 R409 R457C431C433C436 C437 3 FL401 R414R415R420R426R463 C434C435 CR411 Q416 R419 R460 R461R462 SH402 U410 C328 C337 C359C523 R374 R3751 4 5 8 U303VR442 C277C278 C279C522 L505 U248 VR441 VR506 C358 C383 C390R373 R376 R377 R378 R370 R371 R372 C202 C204 C208 C223 C263 C264 C293C298 CR203L261 R204SH202 C201 C219 C231C232 C234 R201R202R231R232 R233 137 25 13U201 C206C207 C218 C224 C258 C259 C265 C296 R281 5 4 3 U210 543 U211 C442 C445R473 VR432 VR433 VR445 VR446 VR448 11 1 20 10U420 C475 R431R498 137 25 13U404 C414 C415 C430 C450 C451 C452 C476 43 Q410 R471 SH403 VR460 C405C408 C409 C410 C411C440 R434R436C407 C416 C419C420 C421C422 C447 C448 C479C481 R400R413 R423R424 R425 R445 R449 R472 R475 R499 C252 C254 C255 CR251L251 R251R252 R254SH242 111 20 10 U241C241 C242 C243 C244 C245 C246 C250 C281 C295 C371C372 C373C378 CR241 CR242 CR243L241 L242 L281 Q310 R110 R 111 R112R241 R242 R244 R245 R330R331R332 R349 C105 C123 C126 C128 C130 C133 C134 C135 C138 C150 C151 C152C170 C174 E101 L112 R102 R109 R130 R131 R132 R136 117 9 25 U102R329 VR439 C172 C173 CR105R172C132 H101 R133 P100C108 CR103CR160 43 Q 111R101 R170 234 1J101 J102 C503 CR306 CR501F501SH304 1 2 3 B501VR444 C306C307 C309 C310 C311 C312 C313 C314C315 C316 C317 C318 C321 C380 CR303 CR304CR305 L303 L304 L305 L306 L307 Q301R303 R304 R305R306 R307 R328R340 SH3024 32 Y300 C355 L331L332R359C334 C350 R366 R367R368R369SH322 11 1 2010 U301 C327 C344 C348 C360 C366 Q302 R311 R312 R344 C326 C361 C382CR311 R313R314R315 C329 C343 C345 C346 C347C351 C357 CR312 CR313 Q320 R350 R358R361 R363 R364 C364 C367 C385L325 R320 R322 R346 4 5 3 2S502 4 C 8 C 21 S501
Circuit Board/Schematic Diagrams and Parts List19FMR-2045A-2December 26, 2003 Figure 2-3. UHF Controls And Switches Schematic Diagram B504 if B503 LI_ION VR5016.8V0.47uF C502 C505 100pFSWITCH S502 4 1 LOW5 HIGH36 TAB1 7 TAB2 2 R507 0 MECH_SWB+ Vdda VOL P100M100M101 VR441 6.8V 6.8V VR442PB503 SWITCH 1 2 .01uFC522 VR444 6.8V1 2SWITCHPB501 2PB502 SWITCH 1 6.8V VR440 .01uFC521 2SWITCHPB504 1 .01uFC523 EMER PTT SB2 SB3SB1 PB505 1 2SWITCH C520 .01uF6.8V VR443 Vdda 4 3 2 R506 47K 5 1 6IMX1 Q50510K R505 R502 180 680 R501 GREEN_LED SWB+ RED_LED Q502 3 1 2 4 CR503CR501 1 210V VR439 100pFC503 24V F501 2 1L505 390nH VR506 6.8V BATT_CODERADIO_CODE UNSWB+ BATT- BATT+DATA 1 NEG 3 POS CONN_JB501 2 BATTERY_CONTACT TAB11TAB22 TAB3 3 TAB4 4 TAB5 5 RF_JACK ANTENNA_NUTJ102 C140 9.75nHL116 1 2 3 J101 RF_JACK 4 GND K2 K3 A1 A2 A3K1 CR160 C141 NUNU RTA0 RTA1 RTA2 RTA3 C514 100pF 100pFC512 C511 C513 100pF 100pFSWITCHS501 C1 GNDGND1 PC0 1 PC1 2 PC2 PC3 C0 C0 C1DUMMY 79 4 8 ZMY0130015-C
20Circuit Board/Schematic Diagrams and Parts ListDecember 26, 2003FMR-2045A-2 Figure 2-4. UHF Receiver Front-End Schematic Diagram CR303 23 1 100K R302 7.5K R340 CR3022.0K R303 100pF C308 100pFC307 C305 13.9nH L30220pF 9.1pF C304 22nH L303C309 100pF 1 Q301 R328 0 3 2 G 3.9pFC303 3.6pFC301100K R301 C302 10pFCR301 L301 13.9nH RX_IN RXFE Bottom Shield RXFE Top Shield RX Mixer Diod Shield SH302 SHIELD 1 1 SHIELDSH304 SH301 SHIELD 1 Mixer Shield 1 SHIELDSH303 G 100pF C321 12K R304C314 0.1uFC315 100pF 180nH L304 100pFC310 510 R305 R5 NUNU L307 13.9nHC317 9.1pF R306 100K C312 6.8pF CR304R307 100K L306 13.9nHC316 R329 3.9pF 0 7.5pF C313C318 10pF 22nHL305 C306 C311CR305 C380 .01uF GR342 100K DACRx G NU 3 1 2 T301 XFMR 4 651 R308 3 1 2 XFMRT302 R309 0 150nHL310 R310 C381CR306 23 4 1 C322 82pF IF NUC375 100pF 16.28nHL309 4 6 3.6K R348 C320 16pF TP302 C319 2.7pF G NUNUNU 10K R330 NU 240 R331 C370 4.7pFVCOBUF C374 100pF C371C378 C372 100pFC373 C386 100pF4.3K R339 13 2Q310 L321 180nHR333 12K R332 0 R349 R5 G RX_INJ 2580541Z02