ATA5283P-6AQ

Features • • • • • • • • Wake-up Function for a Microcontroller with Preamble Detection 1 mVrms Sensitivity 1 µA Standby Current Power Supply: 2 V to 3.8 V Baud Rate: up to 4 kbps (ASK Modulation) Operation Temperature: up to 125°C Withstands +175°C Few External Components Application • Tire Pressure Monitoring (TPM) 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. 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. Block Diagram Interface IC for 125 kHz Wake-up Function ATA5283 Preliminary Battery VDD ATA5283 Lx COIL Amplifier with AGC RESET Vref Conditioner Preamble check N_WAKEUP N_DATA TST1 TST2 GND Rev. 4598D–AUTO–03/04 Pin Configuration Figure 2. Pinning TSSOP8L COIL TST1 TST2 VSS 1 2 3 4 8 7 6 5 VDD N_WAKEUP N_DATA RESET Pin Description Pin 1 2 3 4 5 6 7 8 Symbol COIL TST1 TST2 VSS RESET N_DATA N_WAKEUP VDD Function Antenna coil input Test pin (reserved) Test pin (reserved) Signal ground External reset input Data signal Low active wake-up signal for microcontroller Battery voltage 2 ATA5283 [Preliminary] 4598D–AUTO–03/04 ATA5283 [Preliminary] 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. 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 1.1 Vrms. 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. 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). AGC Amplifier Preamble Detection Figure 3. Communication Protocol Procedure 192 Periods of LF Preamble >5.64 ms >512 Periods of LF Start gap Data Signal N_DATA N_WAKEUP RESET Gain control Current profile No gain control AGC adjustment Gain control active No Gain Control 1 µA 2 µA 0.5 µA 3 4598D–AUTO–03/04 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 4). 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 10). Figure 4. Automatic Gain Control Transmitted signal Coil input Gain control reference Ref.2 100% Gap detection Ref.1 reference 50% Gain controlled signal Internal comparator singal N_DATA 4 ATA5283 [Preliminary] 4598D–AUTO–03/04 ATA5283 [Preliminary] 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 5) 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 5). 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 5). Figure 5. Output Timing Ref.2 Ref.1 Coil input 100% 50% Comparator output N_DATA ta tb tON tc td tOFF 5 4598D–AUTO–03/04 The following diagrams show the delay of the data signal as a function of the antenna Q-factor. Figure 6. Turn On Delay Time (tON) versus Antenna Q-Factor 250 ffield = 125 kHz 200 Typ. Max. ton (µs) 150 100 Min. 50 0 0 10 20 30 40 50 Q-factor Figure 7. Turn Off Delay Time (toff) versus Antenna Q-Factor 200 180 160 140 120 Max. Typ. ffield = 125 kHz toff (µs) 100 80 60 40 20 0 0 10 20 30 40 50 Min. Q-factor 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). 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. 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). 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. 6 ATA5283 [Preliminary] 4598D–AUTO–03/04 ATA5283 [Preliminary] 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 the IC is out of operation and the current consumption is below the standby current. Note: The RESET pin is high impedance CMOS input. To avoid floating effects like undefined input states and malfunctions it should not be open. 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. Applications Figure 8 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: To avoid supply voltage ripples to affect the microcontroller, an RC filter (R1 = 100 Ω, C1 = 10 nF) is recommended. Figure 8. Application R1 C1 8 Amplifier with AGC 125 kHz ATA5283 5 RESET N_WAKEUP N_DATA Temp. Sensor Micro controller Central Board Controller Antenna Driver ATA5275 LA CA 1 ∫ Vref 7 6 2 3 4 Pressure Sensor UHF - Rx T5743 433 MHz UHF - Tx ATAR862 7 4598D–AUTO–03/04 Figure 9. Pin Connection and Pin Protection ATA5283 COIL_X 1 Divider impedance 143 kΩ ... 5 MΩ 8 VDD VDD VDD TST1 2 2k 7 N_WAKEUP VDD VDD VDD TST2 3 2k 6 N_DATA VDD VSS 4 1k 5 RESET Figure 10. Coil Input Impedance 10000 max. typ. min. Z (k Ω ) 1000 100 1 10 100 1000 10000 Coil Input Signal (mV PP ) 8 ATA5283 [Preliminary] 4598D–AUTO–03/04 ATA5283 [Preliminary] Absolute Maximum Ratings Parameters Power supply Input voltage (except coil inputs) Input current coil Input voltage coil ESD protection (human body) Operating temperature range Withstanding 175°C Storage temperature range Soldering temperature Symbol VDD VIN ICI VCI VESD Tamb tTEMP Tstg Tsld Value -0.3 to +6.5 VSS-0.3 < VIN < VDD + 0.3 ±10 VDD-3.5 < VCI < VDD + 3.5 4 -40 to +125 30 -40 to +150 260 Unit V V mA V kV °C min. °C °C Thermal Resistance Parameters Thermal resistance junction ambient Symbol RthJA Value 210 Unit K/W Operating Range Parameters Power supply range Operating temperature range Symbol VDD TOP Value 2 to 3.8 -40 to -125 Unit V °C Electrical Characteristics VSS = 0 V, VDD = 2 V to 3.8 V, Tamb = -40° C to +105°C, characterized up to 125°C, unless other specified No. 1 1.1 Parameters Power supply Reset supply current -40 Reset supply current +25 1.2 Reset supply current +85 Reset supply current +105 Reset supply current +125 Supply current (standby listen mode) -40 Supply current (standby listen mode) +25 1.3 Supply current (standby listen mode) +85 Supply current (standby listen mode) +105 Supply current (standby listen mode) +125 1, 2, 3, 8 IDDL 1.1 1, 2, 3, 8 IDDR 0.4 Test Conditions Pin 8 Symbol VDD Min. 2 Typ. 3.2 Max. 3.8 0.8 0.8 0.8 1.0 1.5 1.4 1.5 1.6 1.6 1.7 Unit V µA µA µA µA µA µA µA µA µA µA Type* A A A C A C A A C A C Power Supply and Coil Limiter *) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter 9 4598D–AUTO–03/04 Electrical Characteristics (Continued) VSS = 0 V, VDD = 2 V to 3.8 V, Tamb = -40° C to +105°C, characterized up to 125°C, unless other specified No. Parameters Supply current with carrier (AGC active) -40 Supply current with carrier (AGC active) +25 1.4 Supply current with carrier (AGC active) +85 Supply current with carrier (AGC active) +105 Supply current with carrier (AGC active) +125 ICI = ± 1 mA VDD = 2 V ICI = ± 1 mA VDD = 3.2 V ICI = ± 1 mA VDD = 3.8 V 2 2.1 2.2 2.3 2.4 2.5 2.6 3 3.1 Amplifiers Wake-up sensitivity Bandwidth Upper corner frequency Lower corner frequency Input impedance Input capacitance Automatic Gain Control Preamble detection time VIN ≥ 3 mVrms at 125 kHz f = 125 kHz VIN = 1 mVrms VIN = 3 mVrms VIN = 30 mVrms VIN = 100 mVrms VIN = 1 Vrms Coil input signal 100% to 37% (τ ) Coil input signal: 50 to 100% changing Coil input signal: 100 to 50% changing 125 kHz ASK 125 kHz ASK 125 kHz ASK 1 1 1 tAGC tAGC tAGC tAGC tAGC tEOS tCORR tCORR DR tON tOFF 4 40 40 0 48 220 292 450 tDAGC 192 Periods B 125 kHz input signal Without coil Without coil Without coil f = 125 kHz VIN ≥ 1 mVrms at 125 kHz 7 6 6 6 1 1 VSENS BW fu fo RIN CIN 143 10 1 150 180 30 2.2 mVrms kHz kHz kHz kΩ pF A C C C A C 1-3 VC ±1.4 ±1.6 ±1.8 1,2, 3, 8 IDD 2 Test Conditions Pin Symbol Min. Typ. Max. 4.0 4.1 4.2 4.2 4.2 Unit µA µA µA µA µA Vp Vp Vp Type* A A C A C A A A 1.5 Coil input voltage referred to VDD (Input coil limiter for channels X, Y, Z) 3.2 AGC adjustment time Periods C 512 20 52 208 Periods Periods Periods kbits/s µs µs C C C A A A 3.3 Signal change rate (gap detection) AGC correction time (no gap detection) Data rate (Q < 20) Delay time RF signal to data Delay time RF signal to data 3.4 3.5 3.6 3.7 *) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter 10 ATA5283 [Preliminary] 4598D–AUTO–03/04 ATA5283 [Preliminary] Electrical Characteristics (Continued) VSS = 0 V, VDD = 2 V to 3.8 V, Tamb = -40° C to +105°C, characterized up to 125°C, unless other specified No. 4 4.1 4.1.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 5 5.1 5.2 5.3 Parameters Interface Reset input level high Reset pulse width Reset input level low Reset input leakage current low Reset input leakage current high N_WAKEUP output level high N_WAKEUP output level low N_DATA output level high N_DATA output level low Power Supply and Reset VDD power on reset threshold Power-up time RESET reactivation caused by negative spikes on VDD Switch on VDD to circuit active tBDN = 500 ns 7 VPOR tPON tRST 10 1 1.5 1.9 100 200 V ms µs A C C VRESET = VSS VRESET = VDD INWAKEUP = -100 µA INWAKEUP = 100 µA IN_DATA = -100 µA IN_DATA = 100 µA VRESET = VDD 5 5 5 5 5 7 7 6 6 VHRESET tRESET VLRESET IIL IIH VHNWAKE VLNWAKE VHNDATA VLNDATA 0.8 × VDD 20 0 -0.2 0 0.8 × VDD 0 0.8 × VDD 0 0.2 × VDD 0 0.2 VDD 0.2 × VDD VDD 0.2 × VDD VDD V µs V µA µA V V V V A A C A A A A A A Test Conditions Pin Symbol Min. Typ. Max. Unit Type* *) Type means: A = 100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter 11 4598D–AUTO–03/04 Ordering Information Extended Type Number ATA5283P-6AQ ATA5283P-6AP Package TSSOP8L TSSOP8L Remarks Taped and reeled Taped and reeled Package Information 12 ATA5283 [Preliminary] 4598D–AUTO–03/04 ATA5283 [Preliminary] Revision History Changes from Rev. 4598C - 08/03 to Rev. 4598D - 03/04 Please note that the following page numbers referred to in this section refer to the specific revision mentioned, not to this document. 1. Electrical Characteristics table: some values changed 2. Ordering Information changed 13 4598D–AUTO–03/04 Atmel Corporation 2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 487-2600 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 1150 East Cheyenne Mtn. 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