ATA5756 ATMEL Corporation, ATA5756 Datasheet
ATA5756
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ATA5756 Summary of contents
Page 1
... RF low-cost transmission systems at data rates kBaud Manches- ter coding and 40 kBaud NRZ coding. The transmitting frequency range is 313 MHz to 317 MHz (ATA5756) and 432 MHz to 448 MHz (ATA5757), repectively. It can be used in both FSK and ASK systems. Due to its shorten crystal oscillator settling time it is well suited for Tire Pressure Monitoring (TPM) and for Passive Entry Go applications ...
Page 2
... ASK modulation and enables the PLL and XTO if the ENABLE pin is open Switches off the FSK switch (switch has high Z if signal at pin FSK is High) and 3 FSK enables the PLL and the XTO if the ENABLE pin is open ATA5756/ATA5757 [Preliminary CLK ASK 2 9 ...
Page 3
... If ENABLE is connected to GND and the ASK or FSK pin is High, the device 10 ENABLE stays in idle mode. In normal operation ENABLE is left open and ASK or FSK is used to enable the device. 4702D–RKE–02/04 ATA5756/ATA5757 [Preliminary] Configuration (FSK < 0.25V) AND (ENABLE > 1.7V) XTO2 VS 1.5k XTO1 182 µA ...
Page 4
... PA can be switched on and the data transmis- sion can start. This results in a significantly lower time of about 0.85 ms between enabling the ATA5756/ATA5757 and the beginning of the data transmission which saves battery power especially in tire pressure monitoring systems. ...
Page 5
... To achieve a faster start-up of the crystal oscillator, the FSK pin should be High during start-up of the XTO because the series resistance of the resonator seen from pin XTO1 is lower if the switch is off. The different modes of the ATA5756/ATA5757 are listed in Table 1, the corresponding current consumption values can be found in the table “Electrical Characteristics” on page 15. ...
Page 6
... XTO and CLK are ready. After another time period of 250 µs, the PLL is locked and ready to transmit. The power amplifier is switched on with ASK = H. The ATA5756/ATA5757 is then ready for FSK modulation. The microcontroller starts to switch on and off the capacitor between the crystal load capacitor and GND by means of pin FSK, thus, changing the reference fre- quency of the PLL ...
Page 7
... CLK Power-up, Power-down The ATA5756/ATA5757 is activated by ENABLE = High, FSK = High and ASK = Low. After activation the microcontroller is switched to external clocking. After typically 0.6 ms, the CLK driver is activated automatically (the microcontroller waits until the XTO and CLK are ready). After another time period of 250 µs, the PLL is locked and ready to transmit ...
Page 8
... Accuracy of Frequency Deviation ATA5756/ATA5757 [Preliminary] 8 Figure 7. Timing ASK Mode with ENABLE Connected to the Microcontroller T XTO ENABLE FSK ASK CLK Power-up, Power-down The accuracy of the frequency deviation using the XTAL pulling method is about 20% if the following tolerances are considered. One important aspect is that the values of C ...
Page 9
... C = 5.5 fF increases the tolerance to 21.07 ppm output CLK signal of 1.64 MHz (ATA5756 operating at 315 MHz) and 1.69 MHz (ATA5757 operating at 433.92 MHz) is provided for a connected microcontroller. The delivered signal is CMOS-compatible with a High and Low time of >125 ns if the load capacitance is lower than 20 pF. The CLK output is Low in power-down mode due to an internal pull-down resistor ...
Page 10
... Output power measurement can be done with the circuit as shown in Figure 9. Please note that the component values must be changed to compensate the individual board parasitics until the ATA5756/ATA5757 has the right load impedance. Also, the damping of the cable used to measure the output power must be calibrated. ...
Page 11
... Figure 10 on page 12 and Figure 11 on page 13). C loop antenna to the power amplifier. For C achieve a better tolerance value and to enable it to realize Z with standard values. Together with the pins of ATA5756 and the PCB board wires loop that suppresses the 1 harmonic, hence the position of C Normally, the best suppression is achieved when C the pins ANT1 and ANT2 ...
Page 12
... Figure 10. ASK Application Circuit Loop C1 Antenna L1 VS ATA5756/ATA5757 [Preliminary] 12 BPXY ATARx9x BPXY BPXY OSC1 7 ATA5756/ATA5757 Power up/down EN CLK 24/ ASK PFD FSK 3 CP ANT2 ANT1 5 VCO PA PLL VDD 1 VS VSS 20 BPXY ENABLE 10 GND Ampl. OK XTO1 ...
Page 13
... Figure 11. FSK Application Circuit Loop C1 Antenna L1 VS 4702D–RKE–02/04 ATA5756/ATA5757 [Preliminary] BPXY ATARx9x BPXY BPXY OSC1 7 ATA5756/ATA5757 Power up/down EN CLK 24/ ASK PFD FSK 3 CP ANT2 ANT1 5 VCO PA PLL VDD 1 VS VSS 20 BPXY ENABLE 10 GND 9 C3 ...
Page 14
... Storage temperature Ambient temperature Ambient temperature in power-down mode for V 15 minutes without damage with S V < 0. ENABLE is open, ENABLE V < 0. < 0.25 V ASK FSK Thermal Resistance Parameters Junction ambient ATA5756/ATA5757 [Preliminary] 14 ANT1 ASK FSK ANT2 Symbol tot stg T amb1 3 ...
Page 15
... Supply current, power-up, PA on, FSK Low Z Output power Output power variation for the full temperature and supply voltage range Spurious emission Harmonics Oscillator frequency XTO (= phase comparator frequency) 4702D–RKE–02/04 ATA5756/ATA5757 [Preliminary] = 25°C. All parameters are referred to GND (Pin 9). amb pF and ...
Page 16
... XTO1 Capacitive load at Pin XTO1 FSK modulation frequency rate FSK switch OFF resistance FSK switch OFF capacitance FSK switch ON resistance ASK modulation frequency rate ATA5756/ATA5757 [Preliminary 25°C. All parameters are referred to GND (Pin 9). amb pF, = pF, = ...
Page 17
... C 4. LNOM Parameters ASK input FSK input ENABLE input 4702D–RKE–02/04 ATA5756/ATA5757 [Preliminary] = 25°C. All parameters are referred to GND (Pin 9). amb pF and Test Conditions Low level input voltage High level input voltage ...
Page 18
... Ordering Information Extended Type Number ATA5756-6DQ ATA5757-6DQ Package Information MSOP10 ATA5756/ATA5757 [Preliminary] 18 Package Remarks MSOP10 – MSOP10 – 4702D–RKE–02/04 ...
Page 19
... Fax: (81) 3-3523-7581 Disclaimer: Atmel Corporation makes no warranty for the use of its products, other than those expressly contained in the Company’s standard warranty which is detailed in Atmel’s Terms and Conditions located on the Company’s web site. The Company assumes no responsibility for any errors which may appear in this document, reserves the right to change devices or specifications detailed herein at any time without notice, and does not make any commitment to update the information contained herein ...