T5750

Features • Integrated PLL Loop Filter • ESD Protection also at ANT1/ANT2 (4 kV HBM/200 V MM; Except Pin 2: 4 kV HBM/100 V MM) • High Output Power (5.5 dBm) with Low Supply Current (8.5 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 T5750 Description The T5750 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 868 MHz to 928 MHz. It can be used in both FSK and ASK systems. Preliminary Figure 1. System Block Diagram UHF ASK/FSK Remote control transmitter UHF ASK/FSK Remote control receiver 1 Li cell T5750 T5760/ T5761 PLL Demod. Control 1...3 µC Keys Encoder M44Cx9x XTO IF Amp Antenna Antenna VCO PLL XTO Power amp. LNA VCO Rev. 4546B–RKE–07/04 Pin Configuration Figure 2. Pinning TSSOP8L CLK 1 8 ENABLE GND PA_ENABLE 2 T5750 7 ANT2 3 6 VS ANT1 4 5 XTAL Pin Description Pin Symbol Function Configuration VS 1 CLK Clock output signal for micro con roller The clock output frequency is set by the crystal to fXTAL/4 100 100 CLK PA_ENABLE 50k Uref=1.1V 2 PA_ENABLE Switches on power amplifier, used for ASK modulation 20 µA ANT1 3 4 ANT2 ANT1 Emitter of antenna output stage Open collector antenna output ANT2 VS 1.5k 1.2k VS 5 XTAL Connection for crystal XTAL 182 mA 6 7 8 VS GND ENABLE Supply voltage Ground Enable input See ESD protection circuitry (see Figure 8 on page 8) See ESD protection circuitry (see Figure 8 on page 8) ENABLE 200k 2 T5750 [Preliminary] 4546B–RKE–07/04 T5750 [Preliminary] Figure 3. Block Diagram T5750 Power up / down CLK 1 f 4 f 64 ENABLE 8 PA_ENABLE GND 2 PFD 7 CP ANT2 VS 3 LF 6 ANT1 XTAL PA 4 VCO 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 64 × fXTAL hence a 13.5672 MHz crystal is needed for a 868.3 MHz transmitter and a 14.2969 MHz crystal for a 915 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 1.7 V, VPA_ENABLE < 0.25 V Power up, VS = 3.0 V, VENABLE > 1.7 V, VPA_ENABLE > 1.7 V VS = 3.0 V, Tamb = 25° C, f = 868.3 MHz, ZLoad = (166 + j226) Ω Symbol Min. Typ. Max. 350 7