ATA8401 UHF ASK/FSK Industrial Transmitter DATASHEET Features ● Integrated PLL loop filter ● ESD protection (3kV HBM/150V MM) ● High output power (8.0dBm) with low supply current (9.0mA) ● Modulation scheme ASK/FSK ● FSK modulation is achieved by connecting an additional capacitor between the XTAL load capacitor and the open drain output of the modulating microcontroller ● Easy to design-in due to excellent isolation of the PLL from the PA and power supply ● Single Li-cell for power supply ● Supply voltage 2.0V to 4.0V in the temperature range of –40°C to +85°C ● Package TSSOP8L ● Single-ended antenna output with high efficient power amplifier ● CLK output for clocking the microcontroller ● One-chip solution with minimum external circuitry Applications ● Industrial/aftermarket remote keyless entry systems ● Alarm, telemetering, and energy metering systems ● Remote control systems for consumer and industrial markets ● Access control systems ● Home automation ● Home entertainment ● Toys 4984H-INDCO-08/15 1. Description The Atmel® ATA8401 is a PLL transmitter IC, which has been developed for the demands of RF low-cost transmission systems for industrial applications at data rates up to 50kBaud ASK and 32kBaud FSK modulation scheme. The transmitting frequency range is 300MHz to 350MHz. It can be used in both FSK and ASK systems. Figure 1-1. System Block Diagram UHF ASK/FSK Remote control transmitter UHF ASK/FSK Remote control receiver 1 Li cell Atmel ATA8401 Keys Encoder ATARx9x Atmel ATA8201 ATA8203 XTO 4984H–INDCO–08/15 IF Amp Antenna VCO LNA ATA8401 [DATASHEET] Control PLL Antenna 2 1 to 3 Demod PLL LNA VCO XTO Microcontroller 2. Pin Configuration Figure 2-1. Pinning TSSOP8L CLK PA_ENABLE ANT2 ANT1 Table 2-1. Pin ATA8401 1 8 2 7 3 6 4 5 ENABLE GND VS XTAL Pin Description Symbol Function Configuration VS 1 CLK Clock output signal for microcontroller The clock output frequency is set by the crystal to fXTAL/4 100Ω CLK 100Ω PA_ENABLE 2 PA_ENABLE UREF = 1.1V 50kΩ Switches on power amplifier used for ASK modulation 20μA ANT1 3 ANT2 Emitter of antenna output stage 4 ANT1 Open collector antenna output ANT2 ATA8401 [DATASHEET] 4984H–INDCO–08/15 3 Table 2-1. Pin Pin Description (Continued) Symbol Function Configuration VS 1.5kΩ 5 XTAL VS 1.2kΩ Connection for crystal XTAL 182μA 6 VS 7 GND 8 ENABLE Supply voltage See ESD protection circuitry (see Figure 4-5 on page 8) Ground See ESD protection circuitry (see Figure 4-5 on page 8) ENABLE Enable input 200kΩ Figure 2-2. Block Diagram Atmel ATA8401 Power up/down f CLK ENABLE 4 1 8 f 32 PA_ENABLE GND 2 7 PDF CP ANT2 VS 3 6 LF ANT1 4 PA VCO PLL 4 ATA8401 [DATASHEET] 4984H–INDCO–08/15 XTO 5 XTAL 3. General Description This fully integrated PLL transmitter allows particularly simple, low-cost RF miniature transmitters to be assembled. The VCO is locked to 32 fXTAL, and therefore a 9.8438MHz crystal is needed for a 315MHz transmitter. All other PLL and VCO peripheral elements are integrated. The XTO is a series resonance oscillator so that only one capacitor together with a crystal connected in series to GND are needed as external elements. The crystal oscillator together with the PLL typically needs < 3ms until the PLL is locked and the CLK output is stable. There is a wait time of ≥ 3ms until the CLK is used for the microcontroller and the PA is switched on. The power amplifier is an open-collector output delivering a current pulse, which is nearly independent from the load impedance. The delivered output power is therefore controllable via the connected load impedance. This output configuration enables a simple matching to any kind of antenna or to 50. A high power efficiency of = Pout/(IS,PA VS) of 40% for the power amplifier results when an optimized load impedance of ZLoad = (255 + j192) is used at 3V supply voltage. 4. Functional Description If ENABLE = L and the PA_ENABLE = L, the circuit is in standby mode, consuming only a very small amount of current, so that a lithium cell used as power supply can work for several years. With ENABLE = H the XTO, PLL, and the CLK driver are switched on. If PA_ENABLE remains L, only the PLL and the XTO are running, and the CLK signal is delivered to the microcontroller. The VCO locks to 32 times the XTO frequency. With ENABLE = H and PA_ENABLE = H the PLL, XTO, CLK driver, and the power amplifier are on. The power amplifier can be switched on and off with PA_ENABLE. This is used to perform the ASK modulation. 4.1 ASK Transmission The Atmel® ATA8401 is activated by ENABLE = H. PA_ENABLE must remain L for typically ≥ 3 ms, then the CLK signal can be taken to clock the microcontroller and the output power can be modulated by means of the PA_ENABLE pin. After transmission, PA_ENABLE is switched to L and the microcontroller switches back to internal clocking. The Atmel ATA8401 is switched back to standby mode with ENABLE = L. 4.2 FSK Transmission The Atmel ATA8401 is activated by ENABLE = H. PA_ENABLE must remain L for typically ≥ 3ms, then the CLK signal can be taken to clock the microcontroller, and the power amplifier is switched on with PA_ENABLE = H. The chip is then ready for FSK modulation. The microcontroller starts to switch on and off the capacitor between the XTAL load capacitor and GND with an open-drain output port, thus changing the reference frequency of the PLL. If the switch is closed, the output frequency is lower than if the switch is open. After transmission, PA_ENABLE is switched to L, and the microcontroller switches back to internal clocking. The Atmel ATA8401 is switched back to standby mode with ENABLE = L. The accuracy of the frequency deviation with XTAL pulling method is about ±25% when the following tolerances are considered. Figure 4-1. Tolerances of Frequency Modulation VS CStray1 CStray2 LM C4 XTAL CM RS C0 Crystal equivalent circuit C5 CSwitch Using C4 = 8.2pF ±5%, C5 = 10pF ±5%, a switch port with CSwitch = 3pF ±10%, stray capacitances on each side of the crystal of CStray1 = CStray2 = 1pF ±10%, a parallel capacitance of the crystal of C0 = 3.2pF ±10%, and a crystal with CM = 13 fF ±10%, typically results in an FSK deviation of ±21.5kHz with worst case tolerances of ±16.25kHz to ±28.01kHz. ATA8401 [DATASHEET] 4984H–INDCO–08/15 5 4.3 CLK Output An output CLK signal is provided for a connected microcontroller. The delivered signal is CMOS compatible if the load capacitance is lower than 10pF. 4.3.1 Clock Pulse Take-over The clock of the crystal oscillator can be used for clocking the microcontroller. A special feature of Atmel®’s AVR® is that it starts with an integrated RC-oscillator to switch on the Atmel ATA8401 with ENABLE = H, and after 3ms assumes the clock signal of the transmission IC, so that the message can be sent with crystal accuracy. 4.3.2 Output Matching and Power Setting The output power is set by the load impedance of the antenna. The maximum output power is achieved with a load impedance of ZLoad,opt = (255 + j192). There must be a low resistive path to VS to deliver the DC current. The delivered current pulse of the power amplifier is 9mA. The maximum output power is delivered to a resistive load of 400 if the 1.0pF output capacitance of the power amplifier is compensated by the load impedance. An optimum load impedance of: ZLoad = 400 || j/(2 1.0pF) = (255 + j192) thus results for the maximum output power of 8 dBm. The load impedance is defined as the impedance seen from the Atmel ATA8401’s ANT1, ANT2 into the matching network. Do not confuse this large signal load impedance with a small signal input impedance delivered as input characteristic of RF amplifiers and measured from the application into the IC instead of from the IC into the application for a power amplifier. Less output power is achieved by lowering the real parallel part of 400 where the parallel imaginary part should be kept constant. Output power measurement can be done with the circuit shown in Figure 4-2. Note that the component values must be changed to compensate for the individual board parasitics until the Atmel ATA8401 has the right load impedance ZLoad,opt = (255 + j192). Also the damping of the cable used to measure the output power must be calibrated out. Figure 4-2. Output Power Measurement at f = 315MHz VS C1 1nF L1 56nH C2 ANT1 ZLopt 3.3pF ANT2 Note: 4.4 Z = 50Ω Power meter Rin 50Ω For 345MHz C2 has to be changed to 2.7pF Application Circuit A value of C3 = 68nF/X7R is recommended for the supply-voltage blocking capacitor C3 (see Figure 4-3 on page 7 and Figure 4-4 on page 8). C1 and C2 are used to match the loop antenna to the power amplifier where C1 typically is 22pF/NP0 and C2 is 10.8pF/NP0 (18pF + 27pF in series). For C2, two capacitors in series should be used to achieve a better tolerance value and to have the possibility of realizing the ZLoad,opt using standard valued capacitors. C1, together with the pins of Atmel ATA8401 and the PCB board wires, forms a series resonance loop that suppresses the 1st harmonic. Therefore, the position of C1 on the PCB is important. Normally the best suppression is achieved when C1 is placed as close as possible to the pins ANT1 and ANT2. The loop antenna should not exceed a width of 1.5mm, otherwise the Q-factor of the loop antenna is too high. L1 ([50nH to 100nH) can be printed on PCB. C4 should be selected so that the XTO runs on the load resonance frequency of the crystal. Normally, a 15pF load-capacitance crystal results in a value of 12pF. 6 ATA8401 [DATASHEET] 4984H–INDCO–08/15 Figure 4-3. ASK Application Circuit S1 S2 VDD Atmel AVR (ATtiny) BPXY VS 1 VSS BPXY 20 BPXY BPXY OSC1 7 Atmel ATA8401 Power up/down CLK ENABLE f 4 1 8 f 32 PA_ENABLE GND 2 7 PDF C3 C2 CP ANT2 VS 3 6 VS Loop Antenna LF C1 ANT1 XTAL 4 PA VCO PLL L1 XTO XTAL 5 C4 VS ATA8401 [DATASHEET] 4984H–INDCO–08/15 7 Figure 4-4. FSK Application Circuit S1 S2 VDD Atmel AVR (ATtiny) BPXY VS 1 VSS BPXY 20 BP42/T2O BPXY 18 BPXY OSC1 7 Atmel ATA8401 Power up/down CLK ENABLE f 4 1 8 f 32 PA_ENABLE GND 2 7 PDF C3 CP C2 ANT2 VS 6 3 Loop Antenna LF C1 VS C5 ANT1 XTAL 4 PA VCO XTO XTAL 5 PLL L1 C4 VS Figure 4-5. ESD Protection Circuit VS ANT1 CLK GND 8 ATA8401 [DATASHEET] 4984H–INDCO–08/15 PA_ENABLE ANT2 XTAL ENABLE 5. 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 Minimum Maximum Unit Supply voltage VS 5 V Power dissipation Ptot 100 mW Junction temperature Tj 150 °C Storage temperature Tstg –55 +85 °C Ambient temperature Tamb –55 +85 Input voltage VmaxPA_ENABLE –0.3 Note: 1. If VS + 0.3 is higher than 3.7V, the maximum voltage will be reduced to 3.7V. 6. (VS + 0.3) V Thermal Resistance Parameters Junction ambient 7. °C (1) Symbol Value Unit RthJA 170 K/W Electrical Characteristics VS = 2.0V to 4.0V, Tamb = 25°C unless otherwise specified. Typical values are given at VS = 3.0V and Tamb = 25°C. All parameters are referred to GND (pin 7). Parameters Test Conditions Supply current Power down, VENABLE < 0.25V, –40°C to 85°C VPA-ENABLE < 0.25V, 25°C (100% correlation tested) Supply current Symbol Min. Typ. Max. Unit 350 nA nA IS_Off < 10 Power up, PA off, VS = 3V, VENABLE > 1.7V, VPA-ENABLE < 0.25V IS 3.7 4.8 mA Supply current Power up, VS = 3.0V, VENABLE > 1.7V, VPA-ENABLE > 1.7V IS_Transmit 9 11.6 mA Output power VS = 3.0V, Tamb = 25°C, f = 315 MHz, ZLoad = (255 + j192)W 8.0 10.5 dBm Output power variation for the full temperature range Tamb = 25°C, VS = 3.0V VS = 2.0V PRef PRef –1.5 –4.0 dB dB Output power variation for the full temperature range Tamb = 25°C, VS = 3.0V VS = 2.0V, POut = PRef + PRef PRef PRef –2.0 –4.5 dB dB Achievable output-power range Selectable by load impedance 8.0 dBm PRef POut_typ fCLK = f0/128 Load capacitance at pin CLK = 10pF Spurious emission fO ±1 fCLK fO ±4 fCLK Other spurious are lower Note: 1. If VS is higher than 3.6V, the maximum voltage will be reduced to 3.6V. 6.0 0 –55 –52 ATA8401 [DATASHEET] 4984H–INDCO–08/15 dBc dBc 9 7. Electrical Characteristics (Continued) VS = 2.0V to 4.0V, Tamb = 25°C unless otherwise specified. Typical values are given at VS = 3.0V and Tamb = 25°C. All parameters are referred to GND (pin 7). Parameters Test Conditions Oscillator frequency XTO (= phase comparator frequency) fXTO = f0/32 fXTAL = resonant frequency of the XTAL, CM ≤ 10fF, load capacitance selected accordingly Tamb = 25°C Symbol Min. fXTO PLL loop bandwidth Typ. Max. Unit fXTAL ppm 250 kHz Phase noise of phase comparator Referred to fPC = fXT0, 25kHz distance to carrier –116 –110 dBc/Hz In-loop phase noise PLL 25kHz distance to carrier –86 –80 dBc/Hz Phase noise VCO At 1MHz At 36MHz –94 –125 –90 –121 dBc/Hz dBc/Hz 350 MHz Frequency range of VCO fVCO 300 Clock output frequency (CMOS microcontroller compatible) Voltage swing at pin CLK f0/128 CLoad ≤ 10pF Series resonance R of the crystal V0h V0l VS 0.8 Rs Capacitive load at pin XT0 MHz VS 0.2 V V 110 7 pF FSK modulation frequency rate Duty cycle of the modulation signal = 50% 0 32 kHz ASK modulation frequency rate Duty cycle of the modulation signal = 50% 0 50 kHz Low level input voltage High level input voltage Input current high 0.25 ENABLE input 20 V V µA 0.25 VS(1) 5 V V µA VIl VIh IIn Low level input voltage VIl PA_ENABLE input VIh High level input voltage IIn Input current high Note: 1. If VS is higher than 3.6V, the maximum voltage will be reduced to 3.6V. 10 ATA8401 [DATASHEET] 4984H–INDCO–08/15 1.7 1.7 Ordering Information Extended Type Number Package MOQ ATA8401C-6AQY-66 TSSOP8L 5000 pcs Taped and reeled, Pb-free Package Information 3±0.1 0.1±0.05 3±0.1 +0.06 0.31-0.07 0.65 nom. +0.0 0.85±0.05 +0.05 Dimensions in mm 1-0.15 9. Remarks 0.15-0.025 8. 3.8±0.3 4.9±0.1 3 x 0.65 = 1.95 nom. 8 5 technical drawings according to DIN specifications 1 4 03/15/04 TITLE Package Drawing Contact: [email protected] Package: TSSOP 8L GPC DRAWING NO. REV. 6.543-5083.01-4 2 ATA8401 [DATASHEET] 4984H–INDCO–08/15 11 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 4984H-INDCO-08/15 Section 8 “Ordering Information” on page 11 updated 4984G-INDCO-07/14 Put document in the latest template 4984F-INDCO-08/12 Features on page 1 changed 4984E-INDCO-03/12 4984D-INDCO-12/10 Features on page 1 changed Section 8 “Ordering Information” on page 11 changed Section 1 “Description” on page 1 changed Section 7 “Electrical Characteristics” on page 10 changed Section 4.3.1 “Clock Pulse Take-over” on page 5 changed 4984C-INDCO-04/09 Figure 4-3 “ASK Application Circuit” on page 7 changed Figure 4-4 “FSK Application Circuit” on page 8 changed 4984B-INDCO-11/08 12 ATA8401 [DATASHEET] 4984H–INDCO–08/15 Put document in the latest template Section 4.3.1 “Clock Pulse Take-over” on page 5 changed XXXXXX Atmel Corporation 1600 Technology Drive, San Jose, CA 95110 USA T: (+1)(408) 441.0311 F: (+1)(408) 436.4200 | www.atmel.com © 2014 Atmel Corporation. / Rev.: 4984H–INDCO–08/15 Atmel®, Atmel logo and combinations thereof, Enabling Unlimited Possibilities®, AVR®, and others are registered trademarks or trademarks of Atmel Corporation in U.S. and other countries. Other terms and product names may be trademarks of others. DISCLAIMER: The information in this document is provided in connection with Atmel products. No license, express or implied, by estoppel or otherwise, to any intellectual property right is granted by this document or in connection with the sale of Atmel products. EXCEPT AS SET FORTH IN THE ATMEL TERMS AND CONDITIONS OF SALES LOCATED ON THE ATMEL WEBSITE, ATMEL ASSUMES NO LIABILITY WHATSOEVER AND DISCLAIMS ANY EXPRESS, IMPLIED OR STATUTORY WARRANTY RELATING TO ITS PRODUCTS INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT, CONSEQUENTIAL, PUNITIVE, SPECIAL OR INCIDENTAL DAMAGES (INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS AND PROFITS, BUSINESS INTERRUPTION, OR LOSS OF INFORMATION) ARISING OUT OF THE USE OR INABILITY TO USE THIS DOCUMENT, EVEN IF ATMEL HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. Atmel makes no representations or warranties with respect to the accuracy or completeness of the contents of this document and reserves the right to make changes to specifications and products descriptions at any time without notice. Atmel does not make any commitment to update the information contained herein. Unless specifically provided otherwise, Atmel products are not suitable for, and shall not be used in, automotive applications. Atmel products are not intended, authorized, or warranted for use as components in applications intended to support or sustain life. SAFETY-CRITICAL, MILITARY, AND AUTOMOTIVE APPLICATIONS DISCLAIMER: Atmel products are not designed for and will not be used in connection with any applications where the failure of such products would reasonably be expected to result in significant personal injury or death (“Safety-Critical Applications”) without an Atmel officer's specific written consent. Safety-Critical Applications include, without limitation, life support devices and systems, equipment or systems for the operation of nuclear facilities and weapons systems. Atmel products are not designed nor intended for use in military or aerospace applications or environments unless specifically designated by Atmel as military-grade. Atmel products are not designed nor intended for use in automotive applications unless specifically designated by Atmel as automotive-grade.