Features • • • • • • • • Wake-up Function for a Microcontroller with Preamble Detection 1 mVrms Sensitivity 1 µA Standby Current Power Supply: 2V to 3.8V Baud Rate: up to 4 kbps (ASK Modulation) Operation Temperature: up to 125°C Withstands +175°C Few External Components Interface IC for 125 kHz Wake-up Function Application • Tire Pressure Monitoring (TPM) 1. Description The ATA5283 is a 125 kHz ultra-low power receiver used for the wake-up function of Tire Pressure Monitoring (TPM) application. The sensitive input stage of the IC amplifies and demodulates the carrier signal from the antenna coil to a digital output signal for a microcontroller. During the standby mode the preamble detection unit monitors the incoming signal and activates the wake-up output and the data output, if the IC receives a proper 125 kHz carrier signal. ATA5283 By combining the IC with an antenna coil, a microcontroller, an RF transmitter/transceiver, a battery, temperature- and pressure sensor, it is possible to design a complete Tire Pressure Monitoring system (TPM). Figure 1-1. Block Diagram Battery VDD Lx COIL ATA5283 Amplifier with AGC RESET Vref Conditioner Preamble check N_WAKEUP N_DATA TST1 TST2 GND 4598H–AUTO–03/07 2. Pin Configuration Figure 2-1. Pinning TSSOP8L COIL TST1 TST2 VSS Figure 2-2. 2 1 2 3 4 8 7 6 5 VDD N_WAKEUP N_DATA RESET Pin Description Pin Symbol Function 1 COIL Antenna coil input 2 TST1 Test pin (reserved) 3 TST2 Test pin (reserved) 4 VSS Signal ground 5 RESET External reset input 6 N_DATA Data signal 7 N_WAKEUP 8 VDD Low active wake-up signal for microcontroller Battery voltage ATA5283 4598H–AUTO–03/07 ATA5283 3. Functional Description The ATA5283 is an ultra-low power ASK receiver. Without a carrier signal it operates in the standby listen mode. In this mode it monitors the coil input with a very low current consumption. To activate the IC and the connected control unit, the transmitting stage must send the preamble carrier burst. After a preamble is detected the IC is activated. It adapts the gain of the input stage and enables the wake-up and the data output. The first gap at the end of the preamble generates a wake-up signal for the microcontroller. After that the receiver outputs the data signal at N_DATA. To return the IC into the standby listen mode it must be reset via the RESET input. 3.1 AGC Amplifier The input stage contains an Automatic Gain Control (AGC) amplifier to amplify the input signal from the coil. The gain is adjusted by the automatic gain control circuit if a preamble signal is detected. The high dynamic range of the AGC enables the IC to operate with input signals from 1 mVrms to 1.1Vrms. After the AGC settling time the amplifier output delivers a 125 kHz signal with an amplitude adjusted for the following evaluation circuits’ preamble detection, signal conditioner, wake-up. 3.2 Preamble Detection Before data transmission the IC stays in standby listen mode. To prevent the circuit from unintended operations in a noisy environment the preamble detection circuit checks the input signal. A valid signal is detected by a counter after 192 carrier periods without interrupts. Short interrupts which are suppressed by the signal conditioner are tolerated. When a valid carrier (preamble) is found the circuit starts the automatic gain control. It requires up to 512 carrier periods to settling. The complete preamble should have 704 carrier periods minimum. The preamble is terminated and the data transfer is started with the first gap (Start Gap) in the carrier (see Figure 3-1). Figure 3-1. Communication Protocol Preamble > 5.64 ms Procedure 192 Periods of LF Start gap Data > 512 Periods of LF Signal N_DATA N_WAKEUP RESET Gain control Current profile No gain control 1 µA AGC adjustment Gain control active 2 µA No gain control 0.5 µA 3 4598H–AUTO–03/07 3.3 Automatic Gain Control For a correct demodulation the signal conditioner needs appropriate internal signal amplitude. To control the input signal the ATA5283 has a build in digital AGC. The gain control circuit regulates the internal signal amplitude to the reference value (Ref2, Figure 3-2). It decreases the gain by one step if the internal signal exceeds the reference level for two periods and it increases the gain by one step if eight periods do not achieve the reference level. In the standby listen mode the gain is reset to the maximum value. If a valid preamble signal (192 valid carrier clocks) is detected the automatic gain control is activated. Note: With the variation of the gain the coil input impedance changes from high impedance to minimal 143 kΩ because of the internal regulator circuit (see Figure 3-8 on page 8). Figure 3-2. Automatic Gain Control Transmitted signal Coil input Gain control reference Ref. 2 Gap detection Ref. 1 reference Gain controlled signal 100% 50% Internal comparator signal N_DATA 4 ATA5283 4598H–AUTO–03/07 ATA5283 3.4 Signal Conditioner The signal conditioner demodulates the amplifier output signal and converts it to a binary signal. It compares the carrier signal with the 50% reference level (see Ref1 in Figure 3-3) and delivers a logical 1, if the carrier signal stays below the reference and a logical 0, if it exceeds the reference level. A smoothing filter suppress the space between the half-waves as well as a few missing periods in the carrier and glitches during the gaps. The output signal of the signal conditioner is used as the internal data signal for the data output, the wake-up logic and the preamble detection. The timing of the demodulated data signal is delayed related to the signal at the transmitting end. This delay is a function of the carrier frequency, the behavior of the smoothing filter and the antenna Q-factor. The smoothing filter causes a delay of 3 to 6 periods (see tb and td in Figure 3-3). The rest of the delay is caused by the build-up time of the antenna signal and is conditioned on the Q-factor (see ta and tc in Figure 3-3). Figure 3-3. Output Timing Ref.2 100% Ref.1 50% Coil input Comparator output N_DATA tb tc ta td tON tOFF The following diagrams show the delay of the data signal as a function of the antenna Q-factor. Figure 3-4. Turn On Delay Time (tON) versus Antenna Q-Factor 250 ffield = 125 kHz 200 typ. ton (µs) max. 150 100 min. 50 0 0 10 20 30 40 50 Q-factor 5 4598H–AUTO–03/07 Figure 3-5. Turn Off Delay Time (toff) versus Antenna Q-Factor 200 180 ffield = 125 kHz 160 toff (µs) 140 typ. max. 120 100 80 60 min. 40 20 0 0 10 20 30 40 50 Q-factor 3.5 Data Output The data output N_DATA outputs the demodulated and digitized LF signal according to the envelope of the antenna input signal. In the standby mode the N_DATA output is disabled and set to level 1. It is enabled by the wake-up signal and it outputs 1 level if the IC detects the carrier signal and a 0 level during the gaps (see Figure 3-1 on page 3). As the circuit does not check the received data (except the preamble), it is up to the user to choose the kind of encoding (pulse distance, Manchester, bi-phase...) wanted. 3.6 Wake-up Signal The wake-up signal (N_WAKEUP) indicates that the ATA5283 has detected the end of a preamble signal and has left the standby mode. It can be used as a wake-up or a chip select signal for an external device (see Figure 3-1 on page 3). After a preamble is detected the first valid gap (Start Gap) sets the N_WAKEUP output to low and enables the data output N_DATA. The N_WAKEUP holds the low level until the IC is reset to the standby mode by a reset signal. 3.7 Reset The IC is reset either by the internal POR circuit during a power on sequence or by a high pulse at the RESET pin. After the reset all internal counters are in the initial state and the IC is in the standby listen mode. The POR circuit generates a reset while the supply voltage VDD is below the power on reset threshold VPOR and release the function of the IC if VDD exceeds this threshold. A high signal at the RESET pin resets the complete circuit. If the IC is activated a reset signal is necessary to activate the standby listen mode. The RESET pin can also be used to hold the IC in a power down state. In this state the IC is out of operation and the current consumption is below the standby current. Note: 6 The RESET pin is high impedance CMOS input. To avoid floating effects like undefined input states and malfunctions it should not be open. ATA5283 4598H–AUTO–03/07 ATA5283 3.8 Standby Listen Mode In the standby listen mode the IC monitors the coil input with a very low current consumption. The automatic gain control is switched off and the gain is set to the maximum value. The N_DATA and the N_WAKEUP output are set to a high level. Before the controller enters its standby mode after the communication, it should activate the standby listen mode of the ATA5283 with a reset signal. This measure ensures that the IC enters the power saving standby mode and that the IC wakes the controller correctly with the next preamble signal. 3.9 Applications Figure 3-6 shows a typical TPM application of the ATA5283. Combined with the antenna resonant circuit the ATA5283 is used as wake-up receiver for the microcontroller and the connected temperature- and pressure-sensor. Note: Figure 3-6. To avoid supply voltage ripples to affect the microcontroller, an RC filter (R1 = 100Ω, C1 = 10 nF) is recommended. Application R1 125 kHz Central board controller 8 LA Antenna driver ATA5275 CA 1 Amplifier with AGC C1 ATA5283 5 RESET 7 N_WAKEUP 6 N_DATA Temp. sensor Micro controller Pressure sensor Vref 2 3 4 UHF Rx UHF Tx T5743 433 kHz ATAR862 7 4598H–AUTO–03/07 Figure 3-7. Pin Connection and Pin Protection ATA5283 COIL_X 1 8 VDD 7 N_WAKEUP 6 N_DATA 5 RESET Divider impedance 143 kΩ to 5 MΩ VDD TST1 VDD 2 2 kΩ VDD TST2 VDD VDD 3 2 kΩ VDD VSS 4 1 kΩ Figure 3-8. Coil Input Impedance 10000 max. typ. Z (kΩ) min. 1000 100 1 10 100 1000 10000 Coil Input Signal (mVpp) 8 ATA5283 4598H–AUTO–03/07 ATA5283 4. 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 Symbol Value Unit Power supply VDD –0.3 to +6.5 V Input voltage (except coil inputs) VIN VSS – 0.3 < VIN < VDD + 0.3 V Input current coil ICI ±10 mA VCI VDD – 3.5 < VCI < VDD + 3.5 V ESD protection (human body) VESD 4 kV Operating temperature range Tamb –40 to +125 °C Withstanding 175°C tTEMP 30 min. Storage temperature range Tstg –40 to +150 °C Soldering temperature Tsld 260 °C Symbol Value Unit RthJA 210 K/W Symbol Value Unit Input voltage coil 5. Thermal Resistance Parameters Thermal resistance junction ambient 6. Operating Range Parameters Power supply range VDD 2 to 3.8 V Operating temperature range TOP –40 to +125 °C 9 4598H–AUTO–03/07 7. Electrical Characteristics VSS = 0V, VDD = 2V to 3.8V, Tamb = –40° C to +105°C, characterized up to 125°C, unless other specified No. 1 1.1 Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Type* 8 VDD 2 3.2 3.8 V A 0.8 µA A 0.8 µA A 0.8 µA C Reset supply current +105 1.0 µA A Reset supply current +125 1.5 µA C Supply current (standby listen mode) –40 1.4 µA A Supply current (standby listen mode) +25 1.5 µA A 1.6 µA C Supply current (standby listen mode) +105 1.6 µA A Supply current (standby listen mode) +125 1.7 µA C Supply current with carrier (AGC active) –40 4.0 µA A Supply current with carrier (AGC active) +25 4.1 µA A 4.2 µA C Supply current with carrier (AGC active) +105 4.2 µA A Supply current with carrier (AGC active) +125 4.2 µA C ±1.4 Vp A ±1.6 Vp A ±1.8 Vp A Power Supply and Coil Limiter Power supply Reset supply current –40 Reset supply current +25 1.2 1.3 1.4 1.5 1, 2, 3, 8 Reset supply current +85 1, 2, 3, 8 Supply current (standby listen mode) +85 1,2, 3, 8 Supply current with carrier (AGC active) +85 Coil input voltage referred to VDD (Input coil limiter for channels X, Y, Z) 0.4 IDDR IDDL 1.1 2 IDD ICI = ± 1 mA VDD = 2V ICI = ± 1 mA VDD = 3.2V 1-3 VC ICI = ± 1 mA VDD = 3.8V 2 Amplifiers 2.1 Wake-up sensitivity 125 kHz input signal 7 VSENS 1 mVrms A 2.2 Bandwidth Without coil 6 BW 150 2.2 kHz C 2.3 Upper corner frequency Without coil 6 fu 180 kHz C 2.4 Lower corner frequency Without coil 6 fo 30 kHz C 2.5 Input impedance f = 125 kHz 1 RIN kΩ A Input capacitance VIN ≥ 1 mVrms at 125 kHz 1 CIN pF C 2.6 143 10 *) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter 10 ATA5283 4598H–AUTO–03/07 ATA5283 7. Electrical Characteristics (Continued) VSS = 0V, VDD = 2V to 3.8V, Tamb = –40° C to +105°C, characterized up to 125°C, unless other specified No. Parameters 3 Automatic Gain Control 3.1 Preamble detection time Test Conditions Pin VIN ≥ 3 mVrms at 125 kHz Symbol Min. Typ. tDAGC 192 tAGC tAGC tAGC tAGC tAGC 0 48 220 292 450 Max. Unit Type* Periods B Periods C f = 125 kHz 3.2 AGC adjustment time 3.3 Signal change rate (gap detection) 3.4 AGC correction time (no gap detection) VIN = 1 mVrms VIN = 3 mVrms VIN = 30 mVrms VIN = 100 mVrms VIN = 1Vrms 512 Coil input signal 100% to 37% (τ ) 1 tEOS 20 Periods C Coil input signal: 50 to 100% changing 1 tCORR 52 Periods C Coil input signal: 100 to 50% changing 1 tCORR 208 Periods C 3.5 Data rate (Q < 20) 125 kHz ASK DR 4 Kb/s A 3.6 Delay time RF signal to data 125 kHz ASK tON 40 µs A 3.7 Delay time RF signal to data 125 kHz ASK tOFF 40 µs A V A µs A 4 4.1 4.1.1 Interface Reset input level high Reset pulse width VRESET = VDD 5 VHRESET 0.8 × VDD 5 tRESET 20 5 VLRESET 0 0.2 × VDD V C VDD 4.2 Reset input level low 4.3 Reset input leakage current low VRESET = VSS 5 IIL -0.2 0 µA A 4.4 Reset input leakage current high VRESET = VDD 5 IIH 0 0.2 µA A 4.5 N_WAKEUP output level high INWAKEUP = –100 µA 7 VHNWAKE 0.8 × VDD VDD V A 4.6 N_WAKEUP output level low 7 VLNWAKE 0 0.2 × VDD V A VDD V A 0.2 × VDD V A 1.9 V A tPON 100 ms C TSbydel 800 µs C 200 µs C INWAKEUP = 100 µA 4.7 N_DATA output level high IN_DATA = –100 µA 6 VHNDATA 0.8 × VDD 4.8 N_DATA output level low IN_DATA = 100 µA 6 VLNDATA 0 VPOR 1 5 5.1 5.2 5.2.1 5.3 Power Supply and Reset VDD power on reset threshold Power-up time Switch on VDD to circuit active Standby reactivation delay after pulse reset f = 125 kHz RESET reactivation caused by tBDN = 500 ns negative spikes on VDD 7 tRST 10 1.5 *) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter 11 4598H–AUTO–03/07 8. Ordering Information Extended Type Number Package Remarks ATA5283P-6AQJ TSSOP8L 5000 pieces, taped and reeled, Pb-free ATA5283P-6APJ TSSOP8L 500 pieces, taped and reeled, Pb-free 9. Package Information 3±0.1 +0.06 0.31-0.07 0.65 nom. 3.8±0.3 4.9±0.1 +0.0 0.1±0.05 3±0.1 0.15-0.025 0.85±0.05 +0.05 1-0.15 Package: TSSOP 8L Dimensions in mm 3 x 0.65 = 1.95 nom. 8 5 technical drawings according to DIN specifications Drawing-No.: 6.543-5083.01-4 1 4 Issue: 2; 15.03.04 12 ATA5283 4598H–AUTO–03/07 ATA5283 10. Revision History Please note that the following page numbers referred to in this section refer to the specific revision mentioned, not to this document. Revision No. History 4598H-AUTO-03/07 • Number 5.2.1 in section 7 “Electrical Characteristics” on page 11 added 4598G-AUTO-01/07 • Put datasheet in a new template • Pb-free logo on page 1 deleted 4598F-AUTO-09/05 • • • • Put datasheet in a new template Pb-free logo on page 1 added Heading Rows on Table “Absolute Maximum Ratings” on page 9 added Ordering Information on page 12 changed 13 4598H–AUTO–03/07 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 1150 East Cheyenne Mtn. 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