TMS3705BDRG4

Product Folder Order Now Technical Documents Support & Community Tools & Software TMS3705 SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 TMS3705 Transponder Base Station IC 1 Device Overview 1.1 Features 1 • Base Station IC for TI-RFid™ RF Identification Systems • Drives Antenna • Sends Modulated Data to Antenna • Detects and Demodulates Transponder Response (FSK) 1.2 • • Short-Circuit Protection Diagnosis Sleep-Mode Supply Current: 0.2 mA Designed for Automotive Requirements 16-Pin SOIC (D) Package Applications Car Access Immobilization 1.3 • • • • • • • Building Access Livestock Reader Description The TMS3705 transponder base station IC is used to drive the antenna of a TI-RFid transponder system, to send data modulated on the antenna signal, and to detect and demodulate the response of the transponder. The response of the transponder is a frequency shift keyed (FSK) signal. The high or low bits are coded in two different high-frequency signals (134.2 kHz for low bits and 123 kHz for high bits, nominal). The transponder induces these signals in the antenna coil according an internally stored code. The energy that the transponder needs to send out the data is stored in a charge capacitor in the transponder. The antenna field charges this capacitor in a preceding charge phase. The IC has an interface to an external microcontroller. There are two configurations for the clock supply to both the microcontroller and the base station IC: 1. The microcontroller and base station IC are supplied with a clock signal derived from only one resonator: The resonator is attached to the microcontroller. The base station IC is supplied with a clock signal driven by the digital clock output of the microcontroller. The clock frequency is either 4 MHz or 2 MHz, depending on the selected microcontroller type. 2. The microcontroller and the base station each have their own resonator. The base station IC has an on-chip PLL that generates a clock frequency of 16 MHz for internal clock supply only. Only TMS3705DDRQ1 is recommended in combination with AES transponder products (for example, TRPWS21GTEA or RF430F5xxx). TMS3705EDRQ1 is recommended for best performance in combination with DST40, DST80, MPT transponders (for example, TMS37145TEAx, TMS37126xx, TMS37x128xx, TMS37x136xx, TMS37x158xx, RI-TRP-DR2B-xx, RI-TRP-BRHP-xx) and cannot be used in combination with AES transponder products. Device Information (1) PACKAGE BODY SIZE (2) TMS3705EDRQ1 SOIC (16) 9.9 mm × 3.91 mm TMS3705DDRQ1 SOIC (16) 9.9 mm × 3.91 mm PART NUMBER (1) (2) For the most current part, package, and ordering information for all available devices, see the Package Option Addendum in Section 9, or see the TI website at www.ti.com. The sizes shown here are approximations. For the package dimensions with tolerances, see the Mechanical Data in Section 9. 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. TMS3705 SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 1.4 www.ti.com Functional Block Diagram Figure 1-1 shows the functional block diagram. VDD SCI Encoder Digital Demodulator Limiter Diagnosis Transponder Resonance-Frequency Measurement A_TST SCIO Bandpass 10k Power-On Reset SFB RF Amplifier Control Logic With Mode Control Register Vref TXCT SENSE D_TST Full Bridge PLL VDDA F_SEL ANT1 Predrivers ANT2 Controlled Frequency Divider OSC2 VSSA OSC1 VSS VSSB Copyright © 2016, Texas Instruments Incorporated Figure 1-1. Functional Block Diagram 2 Device Overview Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 TMS3705 www.ti.com SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 Table of Contents 1 2 3 Device Overview ......................................... 1 6.5 RF Amplifier ......................................... 11 1.1 Features .............................................. 1 6.6 Band-Pass Filter and Limiter ........................ 12 1.2 Applications ........................................... 1 6.7 Diagnosis ............................................ 12 1.3 Description ............................................ 1 6.8 Power-on Reset ..................................... 12 1.4 Functional Block Diagram ............................ 2 6.9 Frequency Divider ................................... 12 Revision History ......................................... 3 Device Characteristics .................................. 4 6.10 Digital Demodulator ................................. 12 6.11 Transponder Resonance-Frequency Measurement Related Products ..................................... 4 6.12 SCI Encoder......................................... 13 Terminal Configuration and Functions .............. 5 6.13 Control Logic ........................................ 14 .......................................... 4.2 Signal Descriptions ................................... Specifications ............................................ 5.1 Absolute Maximum Ratings .......................... 5.2 ESD Ratings .......................................... 5.3 Recommended Operating Conditions ................ 5.4 Electrical Characteristics ............................. 6.14 Test Pins ............................................ 16 3.1 4 4.1 5 5 5 7 Applications, Implementation, and Layout........ 17 8 Device and Documentation Support ............... 18 6 6 7.1 Application Diagram ................................. 17 6 8.1 Getting Started and Next Steps ..................... 18 6 8.2 Device Nomenclature ............................... 18 7 8.3 Tools and Software 5.5 Thermal Resistance Characteristics for D (SOIC) Package .............................................. 8 8.4 Documentation Support ............................. 19 Switching Characteristics ............................. 8 8.5 Community Resources .............................. 20 5.6 8.6 Trademarks.......................................... 20 8.7 Electrostatic Discharge Caution ..................... 20 8.8 Export Control Notice 8.9 Glossary ............................................. 20 ..................................... 9 Detailed Description ................................... 11 6.1 Power Supply ....................................... 11 6.2 Oscillator ............................................ 11 6.3 Predrivers ........................................... 11 6.4 Full Bridge ........................................... 11 5.7 6 Pin Diagram 13 Timing Diagrams 9 ................................. ............................... 19 20 Mechanical, Packaging, and Orderable Information .............................................. 21 2 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from October 19, 2016 to October 31, 2018 • • • • Page Updated the paragraph that begins "The base station IC has an on-chip PLL..." in Section 1.3, Description ........... 1 Removed TMS3705A1DRG4, TMS3705BDRG4, and TMS3705CDRQ1 and added TMS3705EDRQ1 in the Device Information table ............................................................................................................. 1 Replaced TMS3705A1DRG4 with TMS3705EDRQ1 in note (F) on Figure 6-1, Operational State Diagram for the Control Logic ......................................................................................................................... 15 Changed the note "Setting not allowed for TMS3705DDRQ1" on Table 6-1, Mode Control Register (7-Bit Register) 16 Revision History Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 3 TMS3705 SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 www.ti.com 3 Device Characteristics Table 3-1 lists the characteristics of the TMS3705. Table 3-1. Device Characteristics Characteristic Data rate (maximum) Frequency 8 kbps 134.2 kHz Required antenna inductance Supply voltage 100 to 1000 µH 4.5 to 5.5 Vdc Transmission principle 3.1 TMS3705 HDX, FSK Related Products For information about other devices in this family of products or related products, see the following links. Products for Wireless Connectivity Connect more – Industry’s broadest wireless connectivity portfolio Products for NFC / RFID Texas Instruments provides one of the industry’s largest, most differentiated NFC product portfolios enabling lower power solutions to meet a broad range of RF connectivity needs. Companion Products for TMS3705 Review products that are frequently purchased or used with this product. Reference Designs The TI Designs Reference Design Library is a robust reference design library that spans analog, embedded processor, and connectivity. Created by TI experts to help you jump start your system design, all TI Designs include schematic or block diagrams, BOMs, and design files to speed your time to market. 4 Device Characteristics Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 TMS3705 www.ti.com SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 4 Terminal Configuration and Functions 4.1 Pin Diagram Figure 4-1 shows the pinout of the 16-pin D (SOIC) package. SENSE 1 16 TXCT SFB 2 15 F_SEL D_TST 3 14 SCIO A_TST 4 13 NC ANT1 5 12 VSS/VSSB OSC1 VSSA 6 11 ANT2 7 10 OSC2 VDDA 8 9 VDD NC – No connection Figure 4-1. 16-Pin D Package (Top View) 4.2 Signal Descriptions Table 4-1 describes the device signals. Table 4-1. Signal Descriptions TERMINAL NO. NAME 1 SENSE 2 SFB 3 4 TYPE Analog input DESCRIPTION Input of the RF amplifier Analog output Output of the RF amplifier D_TST Digital output Test output for digital signals A_TST Analog output Test output for analog signals 5 ANT1 Driver output Antenna output 1 6 VSSA Supply input Ground for the full bridge drivers 7 ANT2 Driver output Antenna output 2 8 VDDA Supply input Voltage supply for the full bridge drivers Supply input Voltage supply for nonpower blocks 9 VDD 10 OSC2 Analog output 11 OSC1 Analog input Oscillator input 12 VSS/VSSB Supply input Ground for nonpower blocks and PLL 13 NC 14 SCIO 15 F_SEL Digital input Control input for frequency selection (default value is high) 16 TXCT Digital input Control input from the microcontroller (default value is high) Oscillator output Not connected Digital output Data output to the microcontroller Terminal Configuration and Functions Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 5 TMS3705 SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 www.ti.com 5 Specifications Absolute Maximum Ratings (1) 5.1 over operating free-air temperature range (unless otherwise noted) MIN MAX VDD Supply voltage range VDD, VSS/VSSB, VDDA, VSSA –0.3 7 V VOSC Voltage range OSC1, OSC2 –0.3 VDD + 0.3 V Vinout Voltage range SCIO, TXCT, F_SEL, D_TST –0.3 VDD + 0.3 Iinout Overload clamping current SCIO, TXCT, F_SEL, D_TST –5 5 VANT Output voltage ANT1, ANT2 –0.3 VDD + 0.3 V IANT Output peak current ANT1, ANT2 –1.1 1.1 A Vanalog Voltage range SENSE, SFB, A_TST –0.3 VDD + 0.3 ISENSE SENSE input current SENSE, SFB, A_TST –5 5 mA ISFB Input current in case of overvoltage SFB –5 5 mA TA Operating ambient temperature –40 85 °C Tstg Storage temperature –55 150 °C 0.5 W PD (1) Total power dissipation at TA = 85°C VESD V ESD Ratings ESD protection (MIL STD 883) VALUE UNIT ±2000 V Recommended Operating Conditions VDD Supply voltage VDD, VSS/VSSB, VDDA, VSSA fosc Oscillator frequency OSC1, OSC2 VIH High-level input voltage F_SEL, TXCT, OSC1 MIN NOM MAX 4.5 5 5.5 4 F_SEL 0.2 VDD IOH High-level output current SCIO, D_TST IOL Low-level output current SCIO, D_TST Specifications V V 0.3 VDD Low-level input voltage UNIT MHz 0.7 VDD TXCT, OSC1 VIL 6 V mA Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. 5.2 5.3 UNIT –1 V mA 1 mA Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 TMS3705 www.ti.com 5.4 SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 Electrical Characteristics VDD = 4.5 V to 5.5 V, fosc = 4 MHz, F_SEL = high, over operating free-air temperature range (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT 8 20 mA 0.015 0.2 mA 2 5 mA/V 10 pF 10 pF Power Supply (VDD, VSS/VSSB, VDDA, VSSA) IDD Supply current Sum of supply currents in Charge phase, without antenna load ISleep Supply current, Sleep state Sum of supply currents in Sleep state, without I/O currents Oscillator (OSC1, OSC2) gosc Transconductance fosc = 4 MHz, 0.5 Vpp at OSC1 0.5 (1) Cin Input capacitance at OSC1 Cout Output capacitance at OSC2 (1) Logic Inputs (TXCT, F_SEL, OSC1) Rpullup Pullup resistance TXCT 120 500 F_SEL 10 500 kΩ Logic Outputs (SCIO, D_TST) VOH High-level output voltage VOL Low-level output voltage 0.8 VDD V 0.2 VDD V 7 14 Ω 40% 42% Full-Bridge Outputs (ANT1, ANT2) ΣRds_on Sum of drain-source resistances Full-bridge N-channel and P-channel MOSFETs at driver current Iant = 50 mA Duty cycle P-channel MOSFETs of full bridge ton1/ton2 Symmetry of pulse durations for the P‑channel MOSFETs of full bridge Ioc Threshold for overcurrent protection toc Switch-off time of overcurrent protection tdoc Delay for switching on the full bridge after an overcurrent Ileak Leakage current Short to ground with 3 Ω 38% 96% 104.5% 220 1100 mA 0.25 10 µs 2.1 ms 1 µA 2 mA 2 2.05 Analog Module (SENSE, SFB, A_TST) ISENSE Input current SENSE, In charge phase VDCREF/ DC reference voltage of RF amplifier, related VDD to VDD 9.25% GBW Gain-bandwidth product of RF amplifier At 500 kHz with external components to achieve a voltage gain of minimum 4‑mVpp and 5-mVpp input signal φO Phase shift of RF amplifier At 134 kHz with external components to achieve a voltage gain of 5-mVpp and 20‑mVpp input signal Vsfb Peak-to-peak input voltage of band pass at which the limiter comparator should toggle (2) At 134 kHz (corresponds to a minimal total gain of 1000) flow Lower cut-off frequency of band-pass filter (3) fhigh Higher cut-off frequency of band-pass filter ΔVhys Hysteresis of limiter –2 (3) A_TST pin used as input, D_TST pin as output, offset level determined by band-pass stage 10% 11% 2 MHz 16 5 ° mV 24 60 100 kHz 160 270 500 kHz 25 50 135 mV 240 µA Diagnosis (SENSE) Idiag (1) (2) (3) (4) Current threshold for operating antenna (4) 80 Specified by design Specified by design; functional test done for input voltage of 90 mVpp. Band-pass filter tested at three different frequencies: fmid = 134 kHz and gain > 30 dB; flow = 24 kHz; fhigh = 500 kHz. Attenuation < –3 dB (reference = measured gain at fmid = 134 kHz). Internal resistance switched on and much lower than external SENSE resistance. Specifications Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 7 TMS3705 SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 www.ti.com Electrical Characteristics (continued) VDD = 4.5 V to 5.5 V, fosc = 4 MHz, F_SEL = high, over operating free-air temperature range (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT 16 16.0166 MHz Phase-Locked Loop (D_TST) fpll PLL frequency Δf/fpll Jitter of the PLL frequency 15.984 6% Power-On Reset (POR) Vpor_r POR threshold voltage, rising VDD rising with low slope 1.9 3.5 V Vpor_f POR threshold voltage, falling VDD falling with low slope 1.3 2.6 V 5.5 Thermal Resistance Characteristics for D (SOIC) Package PARAMETER RθJA (1) Thermal resistance, junction to ambient (1) VALUE UNIT 130 °C/W The junction-to-ambient thermal resistance under natural convection is obtained in a simulation on a JEDEC-standard, High-K board, as specified in JESD51-7, in an environment described in JESD51-2a. 5.6 Switching Characteristics VDD = 4.5 V to 5.5 V, fosc = 4 MHz, F_SEL = high, over operating free-air temperature range (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNIT 2 2.05 2.2 ms 2 2.12 2.2 ms tinit min Time for TXCT high to initialize a new transmission From start of the oscillator after power on or waking up until reaching the Idle state (see Figure 5-1, Figure 5-2, Figure 5-3) tdiag Delay between leaving Idle state and start of diagnosis byte at SCIO Normal operation (see Figure 5-1, Figure 5-2, Figure 5-3) tR Delay between end of charge or end of program and start of transponder data transmit on SCIO See Figure 5-1, Figure 5-2, Figure 5-3. toff Write pulse pause See Figure 5-5. 0.1 tdwrite Signal delay on TXCT for controlling the full bridge Write mode 73 79 85 µs tmcr NRZ bit duration for mode control register See Figure 5-4. 121 128 135 µs tsci NRZ bit duration on SCIO Asynchronous mode (see Figure 5-6) 63 64 tdstop Low signal delay on TXCT to stop Synchronous mode tt_sync Total TXCT time for reading data on SCIO Synchronous mode (see Figure 5-7) tsync TXCT period for shifting data on SCIO Synchronous mode (seeFigure 5-7) 4 tL_sync Low phase on TXCT Synchronous mode (see Figure 5-7) 2 tready Data ready for output after SCIO goes high Synchronous mode (see Figure 5-7) 1 8 Specifications 3 ms ms 65 µs 800 µs 900 µs 64 100 µs 32 tsync – 2 µs 127 µs 128 Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 TMS3705 www.ti.com 5.7 SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 Timing Diagrams TXCT SCIO Diagnostic byte tinit tch Start byte Data bytes tR tdiag Phase MCW Response Charge Initialize transmission NOTE: MCW = Mode control write (to write into the mode control register) Figure 5-1. Default Mode (Read Only, No Writing Into Mode Control Register) TXCT SCIO Diagnostic byte tinit tch Start byte Data bytes tR tdiag Phase MCW Response Charge Initialize transmission NOTE: MCW = Mode control write (to write into the mode control register) Figure 5-2. Read-Only Mode (Writing Into Mode Control Register) TXCT SCIO Diagnostic byte tinit Start byte tprog tch Data bytes tR tdiag Phase MCW Charge Write Program Response Initialize transmission NOTE: MCW = Mode control write (to write into the mode control register) Figure 5-3. Write/Read Mode (Writing Into Mode Control Register) Specifications Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 9 TMS3705 SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 www.ti.com TXCT t init Phase t mcr t mcr Low Bit1 Bit3 Bit2 Bit5 Bit4 Bit6 Bit7 Charge Test bit End transmission Start bit Initialize transmission Figure 5-4. Mode Control Write Protocol (NRZ Coding) TXCT tch Phase toffL toffH Charge tbitH tbitL High bit Low Program Figure 5-5. Transponder Write Protocol SCIO LSB 1 2 3 4 5 6 MSB Stop bit Start bit t sci t sci Figure 5-6. Transmission on SCIO in Asynchronous Mode (NRZ Coding) LSB SCIO 1 2 3 4 5 6 MSB Stop bit Byte ready TXCT t ready t sync t t_sync t sync t L_sync Shift data MCU reads data Figure 5-7. Transmission on SCIO in Synchronous Mode (NRZ Coding) (For Diagnosis Byte and Data Bytes) 10 Specifications Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 TMS3705 www.ti.com SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 6 Detailed Description 6.1 Power Supply The device is supplied with 5 V by an external voltage regulator through two supply pins, one for providing the driver current for the antenna and the analog part in front of the digital demodulator and one for supplying the other blocks. The power supply supplies a power-on reset that brings the control logic into Idle state as soon as the supply voltage drops under a certain value. In Sleep state, the sum of both supply currents is reduced to 0.2 mA. The base station device falls into Sleep state 100 ms after TXCT has changed to high. When TXCT changes to low or is low, the base station IC immediately goes into and remains in normal operation. 6.2 Oscillator The oscillator generates the clock of the base station IC of which all timing signals are derived. Between its input and output a crystal or ceramic resonator is connected that oscillates at a typical frequency of 4 MHz. If a digital clock signal with a frequency of 4 MHz or 2 MHz is supplied to pin OSC1, the signal can be used to generate the internal operation frequency of 16 MHz. The oscillator block contains a PLL that generates the internal clock frequency of 16 MHz from the input clock signal. The PLL multiplies the input clock frequency depending on the logic state of the input pin F_SEL by a factor of 4 (F_SEL is high) or by a factor of 8 (F_SEL is low). In the Sleep state, the oscillator is off. 6.3 Predrivers The predrivers generate the signals for the four power transistors of the full bridge using the carrier frequency generated by the frequency divider. The gate signals of the P-channel power transistors (active low) have the same width (±1 cycle of the 16 MHz clock), the delay between one P-channel MOSFET being switched off and the other one being switched on is defined to be 12 cycles of the 16-MHz clock. In write mode the first activation of a gate signal after a bit pause is synchronized to the received transponder signal by a phase shift of 18°. 6.4 Full Bridge The full bridge drives the antenna current at the carrier frequency during the charge phase and the active time of the write phase. The minimal load resistance the full bridge sees between its outputs in normal operation at the resonance frequency of the antenna is 43.3 Ω. When the full bridge is not active, the two driver outputs are switched to ground. Both outputs of the full bridge are protected independently against short circuits to ground. In case of an occurring short circuit, the full bridge is switched off in less than 10 µs to avoid a drop of the supply voltage. After a delay time of less than 10 ms the full bridge is switched on again to test if the short circuit is still there. An overcurrent due to a resistive short to ground that is higher than the maximum current in normal operation but lower than the current threshold for overcurrent protection does not need to be considered. 6.5 RF Amplifier The RF amplifier is an operational amplifier with a fixed internal voltage reference and a voltage gain of 5 defined by external resistors. The RF amplifier has a high gain-bandwidth product of at least 2 MHz to show a phase shift of less than 16° for the desired signal and to give the possibility to use it as a low-pass filter by adapting additional external components. The input signal of the RF amplifier is DC coupled to the antenna. The amplitude of the output signal of the RF amplifier is higher than 5 mV peak-to-peak. Detailed Description Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 11 TMS3705 SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 6.6 www.ti.com Band-Pass Filter and Limiter The band-pass filter provides amplification and filtering without external components. The lower cut-off frequency is approximately a factor of 2 lower than the average signal frequency of 130 kHz, the higher cut-off frequency is approximately a factor of 2 higher than 130 kHz. The limiter converts the analog sine-wave signal to a digital signal. The limiter provides a hysteresis depending on the minimal amplitude of its input signal. The duty cycle of its digital output signal is between 40% and 60%. The band-pass filter and the limiter together have a high gain of at least 1000. 6.7 Diagnosis The diagnosis is carried out during the charge phase to detect whether the full bridge and the antenna are working. When the full bridge drives the antenna, the voltage across the coil exceeds the supply voltage so that the voltage at the input of the RF amplifier is clamped by the ESD-protection diodes. For diagnosis, the SENSE pin is loaded on-chip with a switchable resistor to ground so that the internal switchable resistor and the external SENSE resistor form a voltage divider, while the internal resistor is switched off in read mode. When the voltage drop across the internal resistor exceeds a certain value, the diagnosis block passes the frequency of its input signal to the digital demodulator. The frequency of the diagnosis signal is accepted if eight subsequent times can be detected, all with their counter state within the range of 112 to 125, during the diagnosis time (at most 0.1 ms). The output signal is used only during the charge phase, otherwise it is ignored. When the short-circuit protection switches off one of the full-bridge drivers, the diagnosis also indicates an improper operation of the antenna by sending the same diagnostic byte to the microcontroller as for the other failure mode. During diagnosis, the antenna drivers are active. In synchronous mode the antenna drivers remain active up to 1 ms after the diagnosis is performed, without any respect to the logic state of the signal at TXCT (thus enabling the microcontroller to clock out the diagnosis byte). 6.8 Power-on Reset The power-on reset generates an internal reset signal to allow the control logic to start up in the defined way. 6.9 Frequency Divider The frequency divider is a programmable divider that generates the carrier frequency for the full-bridge antenna drivers. The default value for the division factor is the value 119 needed to provide the nominal carrier frequency of 134.45 kHz generated from 16 MHz. The resolution for programming the division factor is one divider step that corresponds to a frequency shift of approximately 1.1 kHz. The different division factors needed to cover the range of frequencies for meeting the resonance frequency of the transponder are 114 to 124. 6.10 Digital Demodulator The input signal of the digital demodulator comes from the limiter and is frequency-coded according to the high- and low-bit sequence of the transmitted transponder code. The frequency of the input signal is measured by counting the oscillation clock for the time period of the input signal. As the high-bit and lowbit frequencies are specified with wide tolerances, the demodulator is designed to distinguish the high-bit and the low-bit frequency by the shift between the two frequencies and not by the absolute values. The threshold between the high-bit and the low-bit frequency is defined to be 6.5 kHz lower than the measured low-bit frequency and has a hysteresis of ±0.55 kHz. 12 Detailed Description Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 TMS3705 www.ti.com SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 The demodulator is controlled by the control logic. After the charge phase (that is during read or write phase) it measures the time period of its input signal and waits for the transponder resonance-frequency measurement to determine the counter state for the threshold between high-bit and low-bit frequency. Then the demodulator waits for the occurrence of the start bit. For that purpose, the results of the comparisons between the measured time periods and the threshold are shifted in a 12-bit shift register. The detection of the start bit comes into effect when the contents of the shift register matches a specific pattern, indicating 8 subsequent periods below the threshold immediately followed by 4 subsequent periods above the threshold. A 2-period digital filter is inserted in front of the 12-bit shift register to make a start bit detection possible in case of a nonmonotonous progression of the time periods during a transition from low- to high-bit frequency. The bit stream detected by the input stage of the digital demodulator passes a digital filter before being evaluated. After demodulation, the serial bit flow received from the transponder is buffered byte-wise before being sent to the microcontroller by SCI encoding. 6.11 Transponder Resonance-Frequency Measurement During the prebit reception phase, the bits the transponder transmits show the low-bit frequency, which is the resonance frequency of the transponder. The time periods of the prebits are evaluated by the demodulator counter. Based on the counter states, an algorithm is implemented that ensures a correct measurement of the resonance frequency of the transponder: 1. A time period of the low-bit frequency has a counter state between 112 and 125. 2. The measurement of the low-bit frequency (the average of eight subsequent counter states) is accepted during the write mode, when the eight time periods have counter states in the defined range. The measurement during write mode is started with the falling edge at TXCT using the fixed delay time at which end the full bridge is switched on again. 3. The counter state of the measured low-bit frequency results in the average counter state of an accepted measurement and can be used to update the register of the programmable frequency divider. 4. The measurement of the low-bit frequency (the average of eight subsequent counter states) is accepted during the read mode, when the eight time periods have counter states in the defined range. The start of the measurement during read mode is delayed to use a stable input signal for the measurement. 5. The threshold to distinguish between high-bit and low-bit frequency is calculated to be by a value of 5 or 7 (see hysteresis in threshold) higher than the counter state of the measured low-bit frequency. 6.12 SCI Encoder An SCI encoder performs the data transmission to the microcontroller. As the transmission rate of the transponder is lower than the SCI transmission rate, the serial bit flow received from the transponder is buffered after demodulation and before SCI encoding. The SCI encoder uses an 8-bit shift register to send the received data byte-wise (least significant bit first) to the microcontroller with a transmission rate of 15.625 kbaud (±1.5 %), 1 start bit (high), 1 stop bit (low), and no parity bit (asynchronous mode indicated by the SYNC bit of the Mode Control register is permanently low). The data bits at the SCIO output are inverted with respect to the corresponding bits sent by the transponder. The transmission starts after the reception of the start bit. The start byte detection is initialized with the first rising edge. Typical values for the start byte are 81_H or 01_H (at SCIO). The start byte is the first byte to be sent to the microcontroller. The transmission stops and the base station returns to the Idle state when TXCT becomes low or 20 ms after the beginning of the read phase. TXCT remains low for at least 128 µs to stop the read phase and less than 900 µs to avoid starting the next transmission cycle. Detailed Description Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 13 TMS3705 SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 www.ti.com The SCI encoder also sends the diagnostic byte 2 ms after beginning of the charge phase. In case of a normal operation of the antenna, the diagnostic byte AF_H is sent. If no antenna oscillation can be measured or if at least one of the full-bridge drivers is switched off due to a detected short circuit, the diagnostic byte FF_H is sent to indicate the failure mode. The SCI encoder can be switched into a synchronous data transmission mode by setting the mode control register bit SYNC to high. In this mode, the output SCIO indicates by a high state that a new byte is ready to be transmitted. The microcontroller can receive the 8 bits at SCIO when sending the eight clock signals (falling edge means active) for the synchronous data transmission through pin TXCT to the SCI encoder. 6.13 Control Logic The control logic is the core of the TMS3705 circuit. This circuit contains a sequencer or a state machine that controls the global operations of the base station (see Figure 6-1). This block has a default mode configuration but can also be controlled by the microcontroller through the TXCT serial input pin to change the configuration and to control the programmable frequency divider. For that purpose a mode control register is implemented in this module that can be written by the microcontroller. 14 Detailed Description Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 TMS3705 www.ti.com SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 Power on Sleep Approximately 2 ms after TXCT goes low (see Note D) After approximately 2 ms After approximately 100 ms Idle TXCT is low TXCT goes high before 96 µs 0.9 ms after TXCT goes low (see Note B) or approximately 4 ms after start of receive phase if no start bit is detected or otherwise approximately 20 ms after start of receive phase Mode Control Register Programming See Note C Write bits into mode control register See Note E Mode control register bits received Receive Phase Diagnosis Phase Start of charge phase, Perform diagnosis, Send diagnostic byte approximately 2 ms after leaving Idle state Fail Diagnostic byte sent (see Note A) Frequency measurement, Transponder signal demodulation, Data output to MCU after reception of start byte TXCT remains high for 1.6 ms Write Phase (see Note F) Charge Phase TXCT goes high Charge phase continues A. B. C. D. E. F. Start of write phase, Frequency measurement, Program phase In SCI synchronous mode, this transition always occurs approximately 3 ms after leaving Idle state. Diagnostic byte transmission is complete before the transition. A falling edge on TXCT interrupts the receive phase after a delay of 0.9 ms. TXCT must remain low for at least 128 µs. If TXCT is still low after the 0.9-ms delay, the base station enters the Idle state and then the Diagnosis phase one clock cycle later (see the dotted line marked with "See Note C"). No mode control register can be written, and only the default mode is fully supported in this case. Otherwise, if TXCT returns high and remains high during the delay, the base station stays in Idle state and waits for TXCT to go low (which properly starts a new mode control register programming operation) or waits for 100 ms to enter the Sleep state. This transition occurs only in a special case, as described in Note B. A falling edge on TXCT interrupts the Sleep state. Only the default mode is fully supported when starting an operation from the Sleep state with only one falling edge on TXCT, because of the 2-ms delay. For proper mode control register programming, TXCT must return to high and remain high during this delay. Idle state is the next state in case of undefined states (fail-safe state machine). Frequency measurement is available for the TMS3705EDRQ1 only. Figure 6-1. Operational State Diagram for the Control Logic The default mode is a read-only mode that uses the default frequency as the carrier frequency for the full bridge. Therefore the mode control register does not need to be written (it is filled with low states), and the communication sequence between microcontroller and base station starts with TXCT being low for a fixed time to initiate the charge phase. When TXCT becomes high again, the module enters the read phase and the data transmission through the SCIO pin to the microcontroller starts. There is another read-only mode that differs from the default mode only in the writing of the mode control register before the start of the charge phase. The method to fill the mode control register and the meaning of its contents is described in the following paragraphs. Detailed Description Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 15 TMS3705 SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 www.ti.com The write-read mode starts with the programming of the mode control register. Then the charge phase starts with TXCT being low for a fixed time. When TXCT becomes high again, the write phase begins in which the data are transmitted from the microcontroller to the transponder through the TXCT pin, the control logic, the predrivers, and the full bridge by amplitude modulation of 100% with a fixed delay time. After the write phase TXCT goes low again to start another charge or program phase. When TXCT becomes high again, the read phase begins. The contents of the mode control register (see Table 6-1) define the mode and the way that the carrier frequency generated by the frequency divider is selected to meet the transponder resonance frequency as closely as possible. Table 6-1. Mode Control Register (7-Bit Register) BIT NAME NO. RESET VALUE START_BIT Bit 0 0 DATA_BIT1 Bit 1 0 DATA_BIT2 Bit 2 0 DATA_BIT3 Bit 3 0 DATA_BIT4 Bit 4 0 SCI_SYNC Bit 5 0 RX_AFC Bit 6 0 TEST_BIT Bit 7 0 (1) DESCRIPTION START_BIT = 0 The start bit is always low and does not need to be stored. DATA_BIT[4:1] = 0000 Microcontroller selects division factor 119 DATA_BIT[4:1] = 1111 Division factor is adapted automatically (1) DATA_BIT[4:1] = 0001 Microcontroller selects division factor 114 DATA_BIT[4:1] = 0010 Microcontroller selects division factor 115 ... ... DATA_BIT[4:1] = 0110 Microcontroller selects division factor 119 ... ... DATA_BIT[4:1] = 1011 Microcontroller selects division factor 124 SCI_SYNC = 0 Asynchronous data transmission to the microcontroller SCI_SYNC = 1 Synchronous data transmission to the microcontroller RX_AFC = 0 Demodulator threshold is adapted automatically RX_AFC = 1 Demodulator threshold is defined by DATA_BIT[4:1] TEST_BIT = 0 No further test bytes TEST_BIT = 1 Further test byte follows for special test modes Setting is not allowed for TMS3705DDRQ1. The TMS3705EDRQ1 can adjust the carrier frequency to the transponder resonance frequency automatically by giving the counter state of the transponder resonance-frequency measurement directly to the frequency divider by setting the first 4 bits in high state. The other combinations of the first 4 bits allow the microcontroller to select the default carrier frequency or to use another frequency. The division factor can be selected to be between 114 and 124. Some bits are included for testability reasons. The default value of these test bits for normal operation is low. Bit 7 (TEST_BIT) is low for normal operation; otherwise, the base station may enter one of the test modes. The control logic also controls the demodulator, the SCI encoder, the diagnosis, and the transmission of the diagnosis byte during the charge phase. The state diagram in Figure 6-1 shows the general behavior of the state machine (the state blocks drawn can contain more than one state). All given times are measured from the moment when the state is entered if not specified otherwise. 6.14 Test Pins The IC has an analog test pin A_TST for the analog part of the receiver. The digital output pin D_TST is used for testing the internal logic. Connecting both pins is not required. 16 Detailed Description Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 TMS3705 www.ti.com SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 7 Applications, Implementation, and Layout NOTE Information in the following Applications section is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI's customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 7.1 Application Diagram Figure 7-1 shows a typical application diagram. TMS3705 1 R2 SENSE 2 SFB 3 TXCT F_SEL D_TST SCIO A_TST NC ANT1 VSS VSSA OSC1 16 TXCT Input 15 14 SCIO Output R1 4 L1 5 Antenna 6 C1 7 8 ANT2 OSC2 VDDA VDD 13 12 C3 11 10 Q1 4 MHz C2 9 5V C4 Ground Copyright © 2016, Texas Instruments Incorporated Figure 7-1. Application Diagram Table 7-1 lists the bill of materials for the application in Figure 7-1. Table 7-1. Bill of Materials (BOM) COMPONENT VALUE R1 47 kΩ R2 150 kΩ L1 422 µH at 134 kHz COMMENTS Sumida part number: Vogt 581 05 042 40 C1 3 nF C2 220 pF NPO , COG (high Q types). Voltage rating must be 100 V or higher depending on Q factor. NPO C3 220 pF NPO C4 22 µF Low ESR Q1 4-MHz resonator muRata part number: CSTCR4M00G55B-R0. See resonator data sheet (load capacitance is important). Applications, Implementation, and Layout Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 17 TMS3705 SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 www.ti.com 8 Device and Documentation Support 8.1 Getting Started and Next Steps RFID products from TI provide the ultimate solution for a wide range of applications. With its patented HDX technology, TI RFID offers unmatched performance in read range, read rate and robustness. For more information, see Overview for NFC / RFID. 8.2 Device Nomenclature To designate the stages in the product development cycle, TI assigns prefixes to the part numbers of devices. Each device has one of three prefixes: X, P, or null (no prefix) (for example, TMS3705). Device development evolutionary flow: X Experimental device that is not necessarily representative of the final device's electrical specifications and may not use production assembly flow. P Prototype device that is not necessarily the final silicon die and may not necessarily meet final electrical specifications. null Production version of the silicon die that is fully qualified. X and P devices are shipped against the following disclaimer: "Developmental product is intended for internal evaluation purposes." Production devices have been characterized fully, and the quality and reliability of the device have been demonstrated fully. TI's standard warranty applies. Predictions show that prototype devices (X or P) have a greater failure rate than the standard production devices. TI recommends that these devices not be used in any production system because their expected end-use failure rate still is undefined. Only qualified production devices are to be used. TI device nomenclature also includes a suffix with the device family name. This suffix indicates the package type (for example, D). Figure 8-1 provides a legend for reading the complete device name. For orderable part numbers of TMS3705 devices in the D package types, see the Package Option Addendum in Section 9, the TI website, or contact your TI sales representative. TMS3705 A D R G4 Family Qualification Revision Tape and Reel Packaging Family TMS3705 = Transponder base station IC Revision A1, B, C, D = Silicon revision Packaging http://www.ti.com/packaging Tape and Reel R = Large reel Qualification G4 = Green (RoHS and no Sb, Br) Q1 = Q100 Qualified Figure 8-1. Device Nomenclature 18 Device and Documentation Support Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 TMS3705 www.ti.com 8.3 SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 Tools and Software Design Kits and Evaluation Modules Low-Frequency Demo Reader The ADR2 Evaluation Kit contains a low-frequency reader required to evaluate and operate the TI Car Access products. The kit comes with a reader base board, LF antenna, and a USB-RS232 adapter. Together with the PC software available online, all functions of the reader can be controlled and all automotive transponders, remote keyless entry, and passive entry devices can be addressed. Operation of transponder functions and also passive entry communication is supported by the same system without component changes. PaLFI, Passive Low-Frequency Evaluation Kit TMS37157 The PaLFI Evaluation kit contains all components required to evaluate and operate the TMS37157. The kit comes with an eZ430 MSP430F1612 USB development stick, and an MSP430 target board including an MSP430F2274 plus the TMS37157 PaLFI. A battery board for active operation in addition to an RFID base station reader/writer provide the infrastructure for various evaluation setups. 8.4 Documentation Support The following documentation describes the transponder, related peripherals, and other technical collateral. Receiving Notification of Document Updates To receive notification of documentation updates—including silicon errata—go to the TMS3705 product folder. In the upper right corner, click the "Alert me" button. This registers you to receive a weekly digest of product information that has changed (if any). For change details, check the revision history of any revised document. Application Reports Resonant Trimming Sequence This application report presents an efficient and precise method on how to achieve the desired resonant frequency of configuring the trim array with only a few iterations and measuring the resonant frequency. TMS3705 Range Extender Power Solution Using UCC27424-Q1 This application report provides supplementary information about the TI 134.2-kHz RFID Base Station IC TMS3705x in combination with an external driver IC. In particular, the document shows a low cost and easy-to-implement solution to improve the communication distance between the transaction processor (TRP) and the Reader unit. TMS3705 Passive Antenna Solution The TI low-frequency transponder technology provides the possibility to use a simple passive antenna in combination with various antenna cable lengths. This solution significantly reduces system costs because the active part of the transceiver can be added to the already existing host system; for example, the body control module (BCM) of a vehicle. Integrated TIRIS RF Module TMS3705A Introduction to Low Frequency Reader A TIRIS setup consists of one or more Transponders and a Reader. The Reader described in this application note normally contains the Reader Antenna, the RF Module and the Control Module. More Literature Wireless Connectivity Tri-fold Overview At TI, we are committed to delivering a broad portfolio of wireless connectivity solutions which consume the lowest power and are the easiest to use. With TI innovation supporting your designs, you can share, monitor and manage data wirelessly for applications in wearables, home and building automation, manufacturing, smart cities, healthcare and automotive. MSP430™ Ultra-Low-Power MCUs and TI-RFid Devices The TI portfolio of MSP430 microcontrollers and TI-RFid devices is an ideal fit for low-power, robust RFID reader and transponder solutions. Together, MSP430 and TI-RFid devices help RF designers achieve low power consumption, best-in-class read range and reliable performance at a competitive price. Device and Documentation Support Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 19 TMS3705 SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 8.5 www.ti.com Community Resources The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. TI E2E™ Online Community The TI engineer-to-engineer (E2E) community was created to foster collaboration among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers. TI Embedded Processors Wiki Established to help developers get started with Embedded Processors from Texas Instruments and to foster innovation and growth of general knowledge about the hardware and software surrounding these devices. 8.6 Trademarks TI-RFid, MSP430, E2E are trademarks of Texas Instruments. All other trademarks are the property of their respective owners. 8.7 Electrostatic Discharge Caution This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. 8.8 Export Control Notice Recipient agrees to not knowingly export or re-export, directly or indirectly, any product or technical data (as defined by the U.S., EU, and other Export Administration Regulations) including software, or any controlled product restricted by other applicable national regulations, received from disclosing party under nondisclosure obligations (if any), or any direct product of such technology, to any destination to which such export or re-export is restricted or prohibited by U.S. or other applicable laws, without obtaining prior authorization from U.S. Department of Commerce and other competent Government authorities to the extent required by those laws. 8.9 Glossary TI Glossary This glossary lists and explains terms, acronyms, and definitions. 20 Device and Documentation Support Copyright © 2010–2018, Texas Instruments Incorporated Submit Documentation Feedback Product Folder Links: TMS3705 TMS3705 www.ti.com SCBS881E – JANUARY 2010 – REVISED OCTOBER 2018 9 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. Copyright © 2010–2018, Texas Instruments Incorporated Mechanical, Packaging, and Orderable Information Submit Documentation Feedback Product Folder Links: TMS3705 21 PACKAGE OPTION ADDENDUM www.ti.com 10-Dec-2020 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan (2) Lead finish/ Ball material MSL Peak Temp Op Temp (°C) (3) Device Marking (4/5) (6) TMS3705DDRQ1 ACTIVE SOIC D 16 2500 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 TMS3705DQ1 TMS3705EDRQ1 ACTIVE SOIC D 16 2500 RoHS & Green NIPDAU Level-3-260C-168 HR -40 to 85 TMS3705EQ1 (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of