Manual

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Features

• Minimal External Circuitry Requirements, no RF Components on the PC Board Except

Matching to the Receiver Antenna

• High Sensitivity, Especially at Low Data Rates

• SSO20 and SO20 package

• Fully Integrated VCO

• Supply Voltage 4.5 V to 5.5 V, Operating Temperature Range -40°C to 105°C

• Single-ended RF Input for Easy Adaptation to l/4 Antenna or Printed Antenna on PCB

• Low-cost Solution Due to High Integration Level

• Various Types of Protocols Supported (i.e., PWM, Manchester and Biphase)

• Distinguishes the Signal Strength of Several Transmitters via RSSI (Received Signal

Strength Indicator)

• ESD Protection According to MIL-STD. 883 (4KV HBM)

• High Image Frequency Suppression Due to 1 MHz IF in Conjunction with a SAW Front-

end Filter, up to 40 dB is thereby Achievable with Newer SAWs

• Power Management (Polling) is Possible by Means of a Separate Pin via the

Microcontroller

• Receiving Bandwidth BIF = 600 kHz

Description

The T5744 is a PLL receiver device for the receiving range of f

= 300 MHz to

450 MHz. It is developed for the demands of RF low-cost data communication sys-

tems with low data rates and fits for most types of modulation schemes including

Manchester, Biphase and most PWM protocols. Its main applications are in the areas

of telemetering, security technology and keyless-entry systems.

Figure 1. System Block Diagram

Demod.

IF Amp

LNA VCO

PLL XTO

Data

interface

T5744

1...3

µC

Power

amp.

XTO

VCO

PLL

U2741B

Antenna Antenna

UHF ASK/FSK

Remote control transmitter

UHF ASK

Remote control receiver

Encoder

M44Cx9x

1 Li cell

Keys

UHF ASK

Receiver

T5744

Preliminary

Rev. 4521A–RKE–02/02

Summary of content (19 pages)

PAGE 1
Features • Minimal External Circuitry Requirements, no RF Components on the PC Board Except • • • • • • • • • • • • Matching to the Receiver Antenna High Sensitivity, Especially at Low Data Rates SSO20 and SO20 package Fully Integrated VCO Supply Voltage 4.5 V to 5.5 V, Operating Temperature Range -40°C to 105°C Single-ended RF Input for Easy Adaptation to l/4 Antenna or Printed Antenna on PCB Low-cost Solution Due to High Integration Level Various Types of Protocols Supported (i.e.
PAGE 2
Pin Configuration DVCC XTO LFGND LF LFVCC 14 13 12 11 7 8 9 n.c. 10 MODE 16 5 15 RSSI 17 4 6 TEST 18 3 LNA_IN LNAGND MIXVCC DGND AGND AVCC CDEM BR_1 BR_0 1 T5744 ENABLE 19 2 20 DATA Figure 2.
PAGE 3
T5744 Figure 3. Block Diagram BR_0 BR_1 CDEM ASKDemodulator and data filter RSSI RSSI Dem_out Data interface DATA Test TEST AVCC RSSI IF Amp AGND MODE 4. Order DGND DVCC ENABLE LPF 3 MHz MIXVCC LFGND Standby logic LFVCC IF Amp LPF 3 MHz LNAGND VCO XTO XTO f LNA_IN LF LNA 64 RF Front End The RF front end of the receiver is a heterodyne configuration that converts the input signal into a 1-MHz IF signal.
PAGE 4
Figure 4. PLL Peripherals VS DVCC CL XTO R1 = 820 Ω C9 = 4.7 nF C10 = 1 nF LFGND LF LFVCC VS R1 C10 C9 The passive loop filter connected to Pin LF is designed for a loop bandwidth of BLoop = 100 kHz. This value for BLoop exhibits the best possible noise performance of the LO.
PAGE 5
T5744 Figure 5 shows a typical input matching network for f RF = 315 MHz and f RF = 433.92 MHz using a SAW. Figure 6 illustrates the input matching to 50 Ω without a SAW. The input matching networks shown in Figure 6 are the reference networks for the parameters given in the electrical characteristics. Table 1. Calculation of LO and IF Frequency Conditions Local Oscillator Frequency Intermediate Frequency fRF = 315 MHz, MODE = 0 fLO = 314 MHz fIF = 1 MHz fRF = 433.92 MHz, MODE = 1 fLO = 432.
PAGE 6
Figure 6. Input Matching Network without SAW Filter fRF = 433.92 MHz 8 LNAGND fRF = 315 MHz 8 T5744 9 25n C3 15p T5744 9 LNA_IN RFIN LNAGND 25n C3 33p LNA_IN RFIN 3.3p 3.3p 100p 22n TOKO LL2012 F22NJ 100p 39n TOKO LL2012 F39NJ Please note that for all coupling conditions (see Figure 5 and Figure 6), the bond wire inductivity of the LNA ground is compensated. C3 forms a series resonance circuit together with the bond wire. L = 25 nH is a feed inductor to establish a DC path.
PAGE 7
T5744 Figure 7. RSSI Characteristics 3.0 2.8 max. 2.6 Tamb = 40°C VRRSI (V) 2.4 25°C 2.2 2.0 105°C 1.8 1.6 min. 1.4 1.2 1.0 -130.0 -110.0 -90.0 -70.0 -50.0 -30.0 PRef (dBm) ASK Demodulator and Data Filter The signal coming from the RSSI amplifier is converted into the raw data signal by the ASK demodulator. An automatic threshold control circuit (ATC) is employed to set the detection reference voltage to a value where a good signal-to-noise ratio is achieved.
PAGE 8
Receiving Characteristics The RF receiver T5744 can be operated with and without a SAW front-end filter. In a typical automotive application, a SAW filter is used to achieve better selectivity. The selectivity with and without a SAW front-end filter is illustrated in Figure 7. Note that the mirror frequency is reduced by 40 dB. The plots are printed relatively to the maximum sensitivity. If a SAW filter is used, an insertion loss of about 4 dB must be considered.
PAGE 9
T5744 Pin MODE can now be set in accordance with the desired clock cycle TClk. TClk controls the following application-relevant parameters: Timing of the analog and digital signal processing IF filter center frequency (fIF0) Most applications are dominated by two transmission frequencies: fSend = 315 MHz is mainly used in USA, fSend = 433.92 MHz in Europe. In order to ease the usage of all TClkdependent parameters, the electrical characteristics display three conditions for each parameter.
PAGE 10
Figure 10. Enable Timing (1) Dem_out tee_sig ENABLE DATA Sleep mode Start-up mode I S = I Soff I S = I Son Receiving mode I S = I Son TStart-up Figure 11. Enable Timing (2) Dem_out tee_sig ENABLE DATA Sleep mode I S = I Soff Digital Signal Processing Start-up mode Receiving mode I S = I Son TStart-up I S = I Son The data from the ASK demodulator (Dem_out) is digitally processed in different ways and as a result converted into the output signal DATA.
PAGE 11
T5744 Figure 12. Synchronization of the Demodulator Output TXClk Dem_out Data_out (DATA) tee_sig Figure 13. Debouncing of the Demodulator Output Dem_out DATA tDATA_min tDATA_min tee tDATA_min tee tee Absolute Maximum Ratings Parameters Symbol Min. Max.
PAGE 12
Electrical Characteristics All parameters refer to GND, Tamb = -40°C to +105°C, VS = 4.5 V to 5.5 V, f0 = 433.92 MHz and f0 = 315 MHz, unless otherwise specified. (VS = 5 V, Tamb = 25°C) Parameters Test Conditions 6.76438 MHz Osc. (MODE:1) Symbol Min. Typ. Max. 4.90625 MHz Osc. (MODE:0) Min. Typ. Variable Oscillator Unit Max. Min. Typ. Max. 2.0383 2.
PAGE 13
T5744 Electrical Characteristics (continued) Parameters Test Conditions Maximum input level Input matched according to Figure 6, BER ≤ 10-3 Symbol Min. Typ. Max. Unit -20 dBm 449 MHz -93 -113 -90 -110 dBC/Hz dBC/Hz -55 -47 dBC Pin_max Local Oscillator Operating frequency range VCO Phase noise VCO / LO Spurious of the VCO fVCO fosc = 432.92 MHz at 1 MHz at 10 MHz For best LO noise (design parameter) R1 = 820 Ω C9 = 4.
PAGE 14
Electrical Characteristics (continued) Parameters Test Conditions Dynamic range RSSI amplifier Symbol Min. VRSSI RSSI gain GRSSI RI of Pin CDEM for cut-off frequency calculation 1 fcu_DF = -------------------------------------------------2 × π × R 1 × CDEM Recommended CDEM for best performance BR_Range0 BR_Range1 BR_Range2 BR_Range3 Upper cut-off frequency data filter Upper cut-off frequency BR_Range0 BR_Range1 BR_Range2 BR_Range3 RI Max. Unit 60 DRRSSI RSSI output voltage range Typ. 1.
PAGE 15
T5744 Figure 14. Application Circuit: fRF = 433.92 MHz, without SAW Filter VS C7 2.2uF 10% C6 10nF 10% T5744 C14 39nF 5% GND C13 10nF 10% 1 2 3 BR_0 BR_1 CDEM 4 5 6 AVCC AGND DGND 7 MIXVCC 8 LNAGND 9 LNA_IN 10 NC C3 15pF 5% np0 20 19 18 17 16 DVCC 15 XTO 14 LFGND LF LFVCC 13 12 11 RSSI Q1 C11 12pF 6.76438MHz 2% np0 C8 150pF 10% C16 C17 3.3pF 5% np0 DATA ENABLE C12 10nF 10% C15 150pF 10% KOAX DATA ENABLE TEST RSSI MODE R1 820 5% 100pF 5% np0 L2 TOKO LL2012 F22NJ 22nH 5% C9 4.
PAGE 16
Figure 16. Application Circuit: fRF = 433.92 MHz, with SAW Filter VS C7 2.2uF 10% C6 10nF 10% T5744 C14 39nF 5% GND C13 10nF 10% 1 2 3 BR_0 BR_1 CDEM 4 5 6 AVCC AGND DGND 7 MIXVCC 8 LNAGND 9 LNA_IN 10 NC C3 22pF 5% np0 C15 150pF 10% C16 C17 DATA ENABLE TEST RSSI MODE 20 19 18 17 16 DVCC 15 XTO 14 LFGND LF LFVCC 13 12 11 33nH 5% C2 8.2pF 5% np0 1 2 IN IN_GND 3 4 CASE_GND CASE_GND OUT OUT_GND 5 6 CASE_GND CASE_GND 7 8 Q1 C11 6.
PAGE 17
T5744 Ordering Information Extended Type Number Package Remarks T5744-TKS SSO20 Tube T5744-TKQ SSO20 Taped and reeled T5744-TGS SO20 Tube T5744-TGQ SO20 Taped and reeled Package Information 9.15 8.65 Package SO20 Dimensions in mm 12.95 12.70 7.5 7.3 2.35 0.25 0.25 0.10 0.4 10.50 10.20 1.27 11.
PAGE 18
5.7 5.3 Package SSO20 Dimensions in mm 6.75 6.50 4.5 4.3 1.30 0.15 0.05 0.25 0.65 5.85 20 0.15 6.6 6.
PAGE 19
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