Features • Integrated PLL Loop Filter • ESD Protection (4 kV HBM/ 200 V MM; Except Pin 2: 4 kV HBM/ 100 V MM) also at ANT1/ANT2 • High Output Power (8.0 dBm) with Low Supply Current (9.0 mA) • Modulation Scheme ASK/FSK • • • • • • • • – FSK Modulation is Achieved by Connecting an Additional Capacitor Between the XTAL Load Capacitor and the Open Drain Output of the Modulating Microcontroller Easy to Design-in Due to Excellent Isolation of the PLL from the PA and Power Supply Single Li-cell for Power Supply Supply Voltage 2.0 V to 4.0 V in the Temperature Range of -40° C to 85° C/125° C Package TSSOP8L Single-ended Antenna Output with High Efficient Power Amplifier CLK Output for Clocking the Microcontroller One-chip Solution with Minimum External Circuitry 125° C Operation for Tire Pressure Systems UHF ASK/FSK Transmitter T5753 Description The T5753 is a PLL transmitter IC which has been developed for the demands of RF low-cost transmission systems at data rates up to 32 kBaud. The transmitting frequency range is 310 MHz to 330 MHz. It can be used in both FSK and ASK systems. Figure 1. System Block Diagram UHF ASK/FSK UHF ASK/FSK Remote control transmitter 1 Li cell U3741B/ U3745B/ T5743/ T5744 T5753 Keys Encoder ATARx9x PLL 1...3 Demod. Control Microcontroller Remote control receiver IF Amp Antenna Antenna XTO VCO Power amp. PLL LNA XTO VCO Rev. 4510F–RKE–07/04 Pin Configuration Figure 2. Pinning TSSOP8L CLK PA_ENABLE 1 8 ENABLE 2 7 GND T5753 ANT2 3 6 VS ANT1 4 5 XTAL Pin Description Pin Symbol Function Configuration VS 1 CLK Clock output signal for microcontroller The clock output frequency is set by the crystal to fXTAL/4 100 100 PA_ENABLE 2 PA_ENABLE CLK Uref = 1.1V 50k Switches on power amplifier, used for ASK modulation 20 µA ANT1 3 ANT2 Emitter of antenna output stage 4 ANT1 Open collector antenna output ANT2 VS 1.5k 5 XTAL Connection for crystal VS 1.2k XTAL 182 µA 6 7 VS GND 8 ENABLE Supply voltage Ground See ESD protection circuitry (see Figure 8 on page 8) See ESD protection circuitry (see Figure 8 on page 8) ENABLE 2 200k Enable input T5753 4510F–RKE–07/04 T5753 Figure 3. Block Diagram T5753 Power up/down CLK 1 ENABLE f 8 4 f 32 PA_ENABLE GND 7 2 PFD CP ANT2 VS 6 3 LF ANT1 4 XTAL VCO PA XTO 5 PLL General Description This fully integrated PLL transmitter allows particularly simple, low-cost RF miniature transmitters to be assembled. The VCO is locked to 32 f XTAL hence a 9.8438 MHz crystal is needed for a 315 MHz transmitter. All other PLL and VCO peripheral elements are integrated. The XTO is a series resonance oscillator so that only one capacitor together with a crystal connected in series to GND are needed as external elements. The crystal oscillator together with the PLL needs typically < 3 ms until the PLL is locked and the CLK output is stable. There is a wait time of ≥ 3 ms until the CLK is used for the microcontroller and the PA is switched on. The power amplifier is an open-collector output delivering a current pulse which is nearly independent from the load impedance. The delivered output power is hence controllable via the connected load impedance. This output configuration enables a simple matching to any kind of antenna or to 50 Ω. A high power efficiency of η= Pout/(IS,PA VS) of 40% for the power amplifier results when an optimized load impedance of ZLoad = (255 + j192) Ω is used at 3 V supply voltage. 3 4510F–RKE–07/04 Functional Description If ENABLE = L and the PA_ENABLE = L, the circuit is in standby mode consuming only a very small amount of current so that a lithium cell used as power supply can work for several years. With ENABLE = H the XTO, PLL and the CLK driver are switched on. If PA_ENABLE remains L only the PLL and the XTO is running and the CLK signal is delivered to the microcontroller. The VCO locks to 32 times the XTO frequency. With ENABLE = H and PA_ENABLE = H the PLL, XTO, CLK driver and the power amplifier are on. With PA_ENABLE the power amplifier can be switched on and off, which is used to perform the ASK modulation. ASK Transmission Th e T 57 5 3 i s a c t i v at e d b y E NA B L E = H . P A _ E NA B L E m us t r e ma i n L f or typically ≥ 3 ms, then the CLK signal can be taken to clock the microcontroller and the output power can be modulated by means of Pin PA_ENABLE. After transmission PA_ENABLE is switched to L and the microcontroller switches back to internal clocking. The T5753 is switched back to standby mode with ENABLE = L. FSK Transmission Th e T 57 5 3 i s a c t i v at e d b y E NA B L E = H . P A _ E NA B L E m us t r e ma i n L f or typically ≥ 3 ms, then the CLK signal can be taken to clock the microcontroller and the power amplifier is switched on with PA_ENABLE = H. The chip is then ready for FSK modulation. The microcontroller starts to switch on and off the capacitor between the XTAL load capacitor and GND with an open-drain output port, thus changing the reference frequency of the PLL. If the switch is closed, the output frequency is lower than if the switch is open. After transmission PA_ENABLE is switched to L and the microcontroller switches back to internal clocking. The T5753 is switched back to standby mode with ENABLE = L. The accuracy of the frequency deviation with XTAL pulling method is about ±25% when the following tolerances are considered. Figure 4. Tolerances of Frequency Modulation ~ VS CStray2 CStray1 XTAL ~ CM LM RS C0 Crystal equivalent circuit C4 C5 CSwitch Using C4 = 8.2 pF ± 5%, C5 = 10 pF ± 5%, a switch port with CSwitch = 3 pF ± 10%, stray capacitances on each side of the crystal of C Stray1 = CStray2 = 1 pF ± 10%, a parallel capacitance of the crystal of C0 = 3.2 pF ± 10% and a crystal with CM = 13 fF ± 10%, an FSK deviation of ±21.5 kHz typical with worst case tolerances of ±16.25 kHz to ±28.01 kHz results. CLK Output An output CLK signal is provided for a connected microcontroller, the delivered signal is CMOS compatible if the load capacitance is lower than 10 pF. Clock Pulse Take-over The clock of the crystal oscillator can be used for clocking the microcontroller. Atmel’s ATARx9x has the special feature of starting with an integrated RC-oscillator to switch on the T5753 with ENABLE = H, and after 1 ms to assume the clock signal of the transmission IC, so that the message can be sent with crystal accuracy. 4 T5753 4510F–RKE–07/04 T5753 Output Matching and Power Setting The output power is set by the load impedance of the antenna. The maximum output power is achieved with a load impedance of ZLoad,opt = (255 + j192) Ω. There must be a low resistive path to VS to deliver the DC current. The delivered current pulse of the power amplifier is 9 mA and the maximum output power is delivered to a resistive load of 400 Ω if the 1.0 pF output capacitance of the power amplifier is compensated by the load impedance. An optimum load impedance of: ZLoad = 400 Ω || j/(2 × π 1.0 pF) = (255 + j192) Ω thus results for the maximum output power of 8 dBm. The load impedance is defined as the impedance seen from the T5753’s ANT1, ANT2 into the matching network. Do not confuse this large signal load impedance with a small signal input impedance delivered as input characteristic of RF amplifiers and measured from the application into the IC instead of from the IC into the application for a power amplifier. Less output power is achieved by lowering the real parallel part of 400 Ω where the parallel imaginary part should be kept constant. Output power measurement can be done with the circuit of Figure 5. Note that the component values must be changed to compensate the individual board parasitics until the T5753 has the right load impedance ZLoad,opt = (255 + j192) Ω. Also the damping of the cable used to measure the output power must be calibrated out. Figure 5. Output Power Measurement VS C1 = 1n L1 = 56n ~ Power meter Z = 50 Ω ANT1 ZLopt C2 = 3.3p Rin 50 Ω ANT2 ~ Application Circuit For the blocking of the supply voltage a capacitor value of C3 = 68 nF/X7R is recommended (see Figure 6 on page 6 and Figure 7 on page 7). C1 and C2 are used to match the loop antenna to the power amplifier where C 1 typically is 22 pF/NP0 and C2 is 10.8 pF/NP0 (18 pF + 27 pF in series); for C2 two capacitors in series should be used to achieve a better tolerance value and to have the possibility to realize the ZLoad,opt by using standard valued capacitors. C1 forms together with the pins of T5753 and the PCB board wires a series resonance loop that suppresses the 1st harmonic, hence the position of C1 on the PCB is important. Normally the best suppression is achieved when C1 is placed as close as possible to the pins ANT1 and ANT2. The loop antenna should not exceed a width of 1.5 mm, otherwise the Q-factor of the loop antenna is too high. L1 ([50 nH to 100 nH) can be printed on PCB. C4 should be selected that the XTO runs on the load resonance frequency of the crystal. Normally, a value of 12 pF results for a 15 pF load-capacitance crystal. 5 4510F–RKE–07/04 Figure 6. ASK Application Circuit S1 BPXY S2 VDD ATARx9x 1 VS VSS BPXY 20 BPXY OSC1 BPXY 7 T5753 Power up/down CLK 1 f ENABLE 8 4 f 32 PA_ENABLE GND 7 2 PFD C3 CP C2 VS ANT2 3 Loop Antenna 6 VS LF C1 XTAL ANT1 4 L1 XTAL VCO PA PLL XTO 5 C4 VS 6 T5753 4510F–RKE–07/04 T5753 Figure 7. FSK Application Circuit ATARx9x S1 VDD BPXY 1 S2 VS VSS BPXY 20 BPXY BP42/T2O 18 OSC1 BPXY 7 T5753 Power up/down CLK 1 f ENABLE 8 4 f 32 PA_ENABLE GND 7 2 PFD C3 CP C2 VS ANT2 6 3 Loop Antenna VS LF C1 XTAL ANT1 4 C5 XTAL VCO PA XTO 5 C4 L1 PLL VS 7 4510F–RKE–07/04 Figure 8. ESD Protection Circuit VS ANT1 CLK PA_ENABLE ANT2 XTAL ENABLE GND Absolute Maximum Ratings Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Parameters Maximum Unit Supply voltage VS 5 V Power dissipation Ptot 100 mW Tj 150 °C °C Junction temperature Symbol Minimum Storage temperature Tstg -55 125 Ambient temperature Tamb -55 125 Input voltage Note: VmaxPA_ENABLE -0.3 (VS + 0.3) °C (1) V 1. If VS + 0.3 is higher than 3.7 V, the maximum voltage will be reduced to 3.7 V. Thermal Resistance Parameters Junction ambient 8 Symbol Value Unit RthJA 170 K/W T5753 4510F–RKE–07/04 T5753 Electrical Characteristics VS = 2.0 V to 4.0 V, Tamb = -40° C to 125° C unless otherwise specified. Typical values are given at VS = 3.0 V and Tamb = 25° C. All parameters are referred to GND (pin 7). Parameters Test Conditions Symbol Supply current Power down, VENABLE < 0.25 V, -40° C to 85° C VPA-ENABLE < 0.25 V, -40°C to +125° C VPA-ENABLE < 0.25 V, 25°C (100% correlation tested) IS_Off Supply current Power up, PA off, VS = 3 V, VENABLE > 1.7 V, VPA-ENABLE < 0.25 V IS Supply current Power up, VS = 3.0 V, VENABLE > 1.7 V, VPA-ENABLE > 1.7 V IS_Transmit Output power VS = 3.0 V, Tamb = 25° C, f = 315 MHz, ZLoad = (255 + j192) W PRef Output power variation for the full temperature range Tamb = -40° C to +85° C, VS = 3.0 V VS = 2.0 V Output power variation for the full temperature range Tamb = -40°C to +125°C, VS = 3.0 V VS = 2.0 V, POut = PRef + ∆PRef Achievable output-power range Selectable by load impedance Spurious emission fCLK = f0/128 Load capacitance at Pin CLK = 10 pF fO ± 1 × fCLK fO ± 4 × fCLK other spurious are lower Oscillator frequency XTO (= phase comparator frequency) fXTO = f0/32 fXTAL = resonant frequency of the XTAL, CM ≤10 fF, load capacitance selected accordingly Tamb = -40° C to +85° C, Tamb = -40° C to +125° C Min. Typ. Max. Unit 350 7 nA µA nA 3.7 4.8 mA 9 11.6 mA 8.0 10.5 dBm ∆PRef ∆PRef -1.5 -4.0 dB dB ∆PRef ∆PRef -2.0 -4.5 dB dB 8.0 dBm <10 POut_typ 6.0 0 -55 -52 dBc dBc fXTO -30 -40 PLL loop bandwidth fXTAL +30 +40 250 ppm ppm kHz Phase noise of phase comparator Referred to fPC = fXT0, 25 kHz distance to carrier -116 -110 dBc/Hz In loop phase noise PLL 25 kHz distance to carrier -86 -80 dBc/Hz Phase noise VCO at 1 MHz at 36 MHz -94 -125 -90 -121 dBc/Hz dBc/Hz 330 MHz Frequency range of VCO fVCO 310 Clock output frequency (CMOS microcontroller compatible) Voltage swing at Pin CLK Series resonance R of the crystal f0/128 CLoad ≤10 pF V0h V0l Rs Capacitive load at Pin XT0 Note: VS × 0.8 MHz VS × 0.2 V V 110 Ω 7 pF 1. If VS is higher than 3.6 V, the maximum voltage will be reduced to 3.6 V. 9 4510F–RKE–07/04 Electrical Characteristics (Continued) VS = 2.0 V to 4.0 V, Tamb = -40° C to 125° C unless otherwise specified. Typical values are given at VS = 3.0 V and Tamb = 25° C. All parameters are referred to GND (pin 7). Parameters Test Conditions FSK modulation frequency rate Duty cycle of the modulation signal = 50% ASK modulation frequency rate Duty cycle of the modulation signal = 50% ENABLE input Low level input voltage High level input voltage Input current high VIl VIh IIn PA_ENABLE input Low level input voltage High level input voltage Input current high VIl VIh IIn Note: 10 Symbol Min. Typ. Max. Unit 0 32 kHz 0 32 kHz 0.25 20 V V µA 0.25 VS(1) 5 V V µA 1.7 1.7 1. If VS is higher than 3.6 V, the maximum voltage will be reduced to 3.6 V. T5753 4510F–RKE–07/04 T5753 Ordering Information Extended Type Number Package Remarks T5753-6AQ TSSOP8L Taped and reeled, Marking: T573 Package Information 11 4510F–RKE–07/04 Revision History Please note that the following page numbers referred to in this section refer to the specific revision mentioned, not to this document. Changes from Rev. 4510E-RKE-10/03 to Rev. 4510F-RKE-07/04 1. Abs. Max. Ratings table (page 8): row “Input voltage” added 2. Abs. Max. Ratings table (page 8): table note 1 added 3. El. Char. table (page 10): row “PA_ENABLE input“ changed 4. El. Char. table (page 10): table note 1 added 5. Ordering Information table (page 11): Remarks changed 12 T5753 4510F–RKE–07/04 Atmel Corporation 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 487-2600 Regional Headquarters Europe Atmel Sarl Route des Arsenaux 41 Case Postale 80 CH-1705 Fribourg Switzerland Tel: (41) 26-426-5555 Fax: (41) 26-426-5500 Asia Room 1219 Chinachem Golden Plaza 77 Mody Road Tsimshatsui East Kowloon Hong Kong Tel: (852) 2721-9778 Fax: (852) 2722-1369 Japan 9F, Tonetsu Shinkawa Bldg. 1-24-8 Shinkawa Chuo-ku, Tokyo 104-0033 Japan Tel: (81) 3-3523-3551 Fax: (81) 3-3523-7581 Atmel Operations Memory 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 RF/Automotive Theresienstrasse 2 Postfach 3535 74025 Heilbronn, Germany Tel: (49) 71-31-67-0 Fax: (49) 71-31-67-2340 Microcontrollers 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 La Chantrerie BP 70602 44306 Nantes Cedex 3, France Tel: (33) 2-40-18-18-18 Fax: (33) 2-40-18-19-60 ASIC/ASSP/Smart Cards 1150 East Cheyenne Mtn. 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