TEMIC Semiconductors U2745B UHF ASK Transmitter Description The U2745B is a PLL transmitter IC which has been specially developed for the demands of RF low-cost data transmission systems at data rates up to 20 kBaud. The transmitting frequency range is 310 MHz to 440 MHz. It can be used in ASK systems. The main ap- plications of the U2745B are in the areas of outside Features @ Supply voltage 2.2 V to 4.0 V in the temperature range -40C to 85C @ One-chip solution with minimum external circuitry @ Lower cost than the usual discrete solutions using SAW and transistors @ Very small SSO16 package, pitch 0.635, 150 mil @ Single-Ended Open-Collector output (same anten- nas can be used as in discrete solutions, simpler adaptation of magnetic loop antennas) temperature metering, socket control, garage door opener, consumption metering, light/ fan or aircondition control, jalousies, wireless keyboard and various other consumer market applications. Electrostatic sensitive device. Observe precautions for handling. Zip @ XTO output for clocking the wC, thereby together with M44C090 or M44C890 the optimum system cost-effectiveness @ Very high transmitting frequency accuracy compared to SAW solutions. This enables receivers at lower bandwidth than is possible with SAW resonators. @ ESD protection according to MIL-STD.883 (4KV HBM) except Pins XTO1/ 2, ANT and LF System Block Diagram UHF ASK UHF ASK . Remote control transmitter Remote control receiver 1 Li cell U2745B U3745BM, Demod| 1.3 | I Control -O-+ wC Encoder PLL Keys MA4CX9x IF Amp Antenna Antenna PLL FY XTO -4 Cc I > x KH LNA vco Figure 1. System block diagram Order Information U2745B-MFB SSO16 Tube U2745B-MFBG3 SSO16 Taped and reeled Rev. Al, 16-Dec-99 1(7) Preliminary InformationTEMIC Semiconductors U2745B Pin Description ASK 1 | NW 16 | GND 1 ASK Modulation input ASK 2 EN Enable input EN 2 | 15| PWRSET 3 VCC Supply voltage 4 CLK Clock output vec 3 | 14| PWRVCC 5 GND Ground 6 LFVCC [Supply voltage VCO 7 LFGND _ | VCO ground CLK [4 13] ANT 8 LF _|Cireuit PLL loop U2745B 9 n.c. Not connected GND Is | 12 | PWRGNDI 10 XTO1 _| Connection for crystal 11 | PWRGND2 | Power GND2 LFVCC le | 11 | PWRGND2 12__| PWRGND1 | Power GND1 13 ANT RF output LFEGND 7 | 19| XTO1 14 PWRVCC Supply voltage power amplifier 15 PWRSET | Applied to VCC LE 3 | a me 16 GND Ground Figure 2. Pinning SSO16 Block Diagram ASK Lh GND OR EN My ) PWRSET Power up vcc O ) PWRVCC VCO PA CLK O | ) ANT Oo ' ) PWRGND1 GND | * 64 eq LFVCC O } O PWRGND2 PL f XTO en L LFGND O ) XTO1 LE OA QO nec. U2745B 14919 Figure 3. Block diagram 2 (7) Rev. Al, 16-Dec-99 Preliminary InformationTEMIC Semiconductors U2745B General Description The fully integrated VCO and the single-ended open- collector output allow particularly simple, low-cost RF miniature transmitters to be assembled. The single-ended output enables a considerably simplified adaptation of both a magnetic loop antenna of any form or a A/4 antenna. This is because the load impedance must not be balanced as would be the case with a differential output. The XTOs frequency can be selected at 13.56 MHz or USA 9.844 MHz. At these frequencies, crystals have a very fast start-up time < 1.5 ms, whereby a wait time of 5 to 10 ms is required until the transmitter IC is locked. This means that the processor does not need to poll a lock detect output. Functional Description ASK Transmission The U2745B is activated by EN = Vs. Vasx must remain 0 V for 5 ms, then the output power can be modulated by means of Pin ASK. Vpn remains = Vs during transmis- sion of the message. The ASK input activates the power amplifier and the PLL. Take-Over of the Clock Pulse in the 1C The clock of the crystal oscillator can be used for clocking the uC. The M44C090 and M44C890 have the special feature of starting with an integrated RC oscillator to switch on the U2745B with Vpn = Vs. 5 ms later, the 3.39-MHz clock frequency is present, so that the message can be sent with crystal accuracy. Application Circuit The following component values are recommendations for a typical application. C4, C5, C6 are block capacitors. The values of these capacitors depend on the board layout. C4 = 1 nE C5 = 1 nF C6 = 22 nF are typically used here. For C5, the impedance between f = 100 MHz and. f = 1 GHz should be as low as possible. CLoopl, CLoop2 are selected so that the antenna oscillates in resonance and the adaptation to the appropriate impedance transformation is possible. LFeed is an inductor for the antennas DC current supply. A typical value is LFeed = 220 nH. LFeed can be either printed on the PC_Board or be a discrete component. Further information regarding the application is provided in the description of the RKE Design Kit (U2745B, U3745B). Output Power Measurement The following output network (see figure 4) can be used for output power evaluation, the exact values of L10, C10 are dependent on the layout. L10, C10 is the transformation network to adopt the output impedance of the IC to 50 2. The following table shows the values for an output power of 2 mW and an Rpwrset = 1.2 kQ. 260 + {330 315 2.7 56 433.92 1.8 33 185 + j268 Vs PWRVCC L10 ANT Zoad-opt C10 50 Q 15009 Figure 4. Measurement output network Rev. Al, 16-Dec-99 3 (7) Preliminary InformationU2745B TEMIC Semiconductors +V = 2.2..4.0V 0 ASK ASK TS GND o- Ho, To} EN BN i | PWRSET CLoop2 Oo 2 15 Power R vec Pwrvec PWRSET L os Gp ry LK ANT me C4 LFeed CLK _ a VCO PA At = 350M c | _ . 2 GND PWRGND1 CLoop1 | i : 7 _ 2. 64) LFVCC J PWRGND2 ost 19] [ZNh oi | I xTo 13.56MHz LFGND qn || XTO1 by}1_ }[]}4H Rel] u274sB a - rts P 1 Antenna Figure 5. Application circuit Absolute Maximum Ratings Supply voltage Vs 6 Vv Power dissipation Prot 250 mW Junction temperature Tj 150 C Storage temperature Tste 55 125 C Ambient temperature Tamb 40 85 C Thermal Resistance Junction ambient Rihya 180 K/W 4 (7) Rev. Al, 16-Dec-99 Preliminary InformationTEMIC Semiconductors U2745B Electrical Characteristics All parameters are refered to GND (Pin 5), Vs = 3 V, Tamb = 25C, unless otherwise specified 2.2Vto4.0V @ Tamb The possible operating ranges refer to different circuit conditions: Vs -40C to +85C Supply current (power down) | Vasx, Ven < 0.3 V, Vs <3.6 V Soe 2 10 HA Supply current Vask = GND, Ven = Vs, Vs =3 V TSon 47 6.2 mA (power up, output OFF) Supply current Vask = Vs, Vs =3 V TStransmit mA (power up, output ON) Rpwrset = 1.2 kQ 10 12.5 Output power Vs =3 V, Tamb = 25C, f = 433.92 MHz Rpwrset = 1.2 kQ Pref 1 3 5 dBm Output power variation for f=315 MHz APRef 1.5 dB f= 315 MHz compared to f = 433.92 MHz Pout = PRef + APRef Maximum peak output @P oy = 2.0 mW, Voutmax Vs-0.7V V (peak) antenna voltage The load impedance must be selected to meet the Vout maximum requirement. The supply current is not dependent on the load impedance tolerance. Spurious emission @ Tamb = 25C fo tn x fpc (fpc = 6.78 MHz) Load capacitance at CLK <3 pF f = 230 MHz to 470 MHz Em 40 dBC f< 230 MHz, f > 470 MHz Em 58 dBC Oscillator frequency XTO @ Tamb = 25C Crystal frequency = 13.56 MHz fxto 13.56 13.56 13.56 50 ppm +50 ppm | MHz Loop bandwidth For best LO noise BLoop 100 kHz Loop filter components: C2 =3.9 nF, Cl = 15 nF, R4 = 220 Q Phase noise VCO @ 1 MHz PNyco 90 dBC/Hz @ 36 MHz PNyco 122 Frequency range of the VCO fvco 310 440 MHz Clock output ClKout four 128 MHz (CMOS uC compatible) Load capacitance at CLK CcLK 10 pF Series resonance R of the fxto = 13.56 MHz Rs 80 Q crystal fxto = 9.84 MHz Rs 100 Q ASK modulation frequency Duty cycle of the finodASK 0 20 kHz rate modulation signal = 50% CLK output Output current Low VcL_K =0.2xVs Ig 150 WA Output current Low VcLK = 0.3 x Vs Ig} 200 WA Output current High Vc_K =0.8xVs Toh 150 pA Output current High VcLK = 0.7 x Vs Toh 200 100 pA ASK input Low level input voltage VASKI 0.3 Vv High level input voltage VASKh 1.7 Vv Input current High TasKh 140 pA Enable ASK VEN Low level input voltage VFESKI 0.3 Vv High level input voltage VFESKh 1.7 Vv Input current High Teskh 140 pA Rev. Al, 16-Dec-99 5 (7) Preliminary InformationU2745B Package Information Package SSO16 Dimensions in mm 5.00 max 5.00 4.80 3.95 max 5.2 48 a6 technical drawings according to D specifications TEMIC Semiconductors 13045 6 (7) Preliminary Information Rev. Al, 16-Dec-99