U4221B Radio Controlled Clock Receiver Description The U4221B is a bipolar integrated straight through receiver circuit in the frequency range of 60 to 80 kHz. The device is designed for radio controlled clock application. Features D Stop-function available D Only a few external components necessary D Digitized serial output signal D Low power consumption D Very high sensitivity D High selectivity by quartz resonator Block Diagram PON 14 VCCA 16 Power supply VCCD 9 NC 10 FSI 12 TCO 13 Driver Comparator FSS 11 GND 15 AGC CAGC 4 IN2 1 Amplifier 2 Amplifier 1 IN1 2 3 GND (analog) 8 OUTA1 6 Demodulator 7 GND (digital) INA2 5 CDEM 93 7506 e Figure 1. TELEFUNKEN Semiconductors Rev. A1, 15-May-96 1 (12) Preliminary Information U4221B Pin Description Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Symbol IN2 IN1 GND CAGC CDEM INA2 GND OUTA1 VCCD NC FSS FSI TCO PON GND VCCA Function Amplifier 1 - Input 2 Amplifier 1 - Input 1 Analog ground Time constant of AGC Low pass filter Amplifier 2 input Digital ground Amplifier 1 output Supply voltage (digital) Not connected Field strength select Field strength indication Time code output Power ON/OFF control Ground (substrate) Supply voltage (analog) VCCA IN2 1 16 IN1 2 15 GND 3 14 CAGC 4 13 TCO GND PON U 4221 B CDEM 5 12 FSI INA2 6 11 FSS GND 7 10 NC OUTA1 8 9 VCCD 93 7507 e IN1, IN2 CDEM IN2 is connected to Pin 16 (VCCA). A ferrite antenna is connected between IN1 and IN2. Q of antenna circuit should be as high as possible, but the temperature influence must be compensated. The resonant resistance should be 200 kW to 300 kW for optimal sensitivity. After demodulation the signal is low pass filtered by the capacitor CDEM. OUTA1, INA2 To achieve a high selectivity, a quartz resonator is connected between the pins OUTA1 and INA2. It is used with the serial resonance frequency of the time code transmitter (e.g. 60 kHz WWVB, 77.5 kHz DCF). The parasitic parallel capacitance C0 of the quartz resonator should be 0.5 pF to 1 pF. CAGC PON If PON is connected to VCCD, the U4221B receiver IC will be activated. The set-up time is typical 2.5 s after applying VCCD at this pin. If PON is connected to GND, the receiver will go into stop mode. FSS This pin is connected to GND, otherwise the field strength indication FSI is disabled. FSI A control voltage derived from the field strength is generated to control the amplifiers. The time constant of this automatic gain control (AGC) is influenced by the capacitor CAGC. If the voltage at the input of amplifier 1 is higher than about 5 mV, FSI will be high. 2 (12) Preliminary Information TELEFUNKEN Semiconductors Rev. A1, 15-May-96 U4221B TCO The digitized serial signal of the time code transmitter can be directly decoded by a microcomputer. Details about the time code format of several transmitters are described separately. The output consists of a PNP current source and a NPN switching transistor TS. The guaranteed source output current is 0.2 µA (TCO = high) and the sink current is 1 µA (TCO = low). Considering these output currents, the supply voltage and the switching levels of the following µC, the lowest load resistance is defined. The maximum load capacitance is 100 pF. In order to improve the driving capability an external pull-up resistor can be used. The value of the resistor should be 4.7 MW. To prevent an undefined output voltage in the power-down state of the U4221B, the use of this pull-up resistor is recommended. An additional improvement of the driving capability may be achieved by using a CMOS driver circuit or a NPN transistor with pull-up resistor connected to the collector (see figure 2). Using a CMOS driver this circuit must be connected to VCCD. pin 9 VCCD 4.7 MW ISOURCE 0.2 mA 100 kW TCO TS ISINK 1 mA pin13 TCO Condition for signal reception: S/N ≈ 4 at comparator input. Important parameters are: VNA = (4 k T Rres)1/2 BWA = fres/QA input noise voltage density of preamplifier: VNA1: 40 nV/Hz1/2 (typ) bandwidth of preamplifier: BWA1: 60 kHz (typ) bandwidth of crystal filter: BWCF: 16 Hz (typ) ultimate attenuation of crystal filter: DCF: –35 dB (typ) whereas: VNA k T BWA fres QA VN Functional Description Ǹ The equivalent input noise voltage at the preamplifier input is: 93 7689 e Figure 2. @ antenna noise voltage density 1.38 10–23 Ws/K (Boltzmann constant) absolute temperature bandwidth of antenna resonant frequency Q antenna + ǒ V NA @ ǸBW Ǔ ) 2 CF ǒ Ǔ Ǔ ǒ Ǔ @@@) ǒV @ ǸBW ) Figure 3 shows the principal function of the receiver (simplified consideration). 93 7521 e Rres CF A1 A 2 and Demodulator Comparator Figure 3. Rres: resonant resistance, A1: preamplifier, A2: amplifier 2, CF: crystal filter TELEFUNKEN Semiconductors Rev. A1, 15-May-96 NA1 CF A CF 2 The following description gives you some additional information and hints in order to facilitate your design, in particular the problems of the antenna. @ ǸBW ) @@ D 2 V NA V NA1 @ ǸBW 2 A1 D CF whereas: Rres = 300 kW, BWA = 1 kHz then VN ≈ 0.4 mV The condition for signal reception is: S/N ≈ 4 ⇒ sensitivity ≈ 1.6 mV That means that the noise voltage of antenna within the bandwidth of the crystal filter dominates and the bandwidth of antenna is uncritical for the sensitivity aspect. 3 (12) Preliminary Information U4221B There is some consideration concerning the calculation of Rres: it is easy to compute the resonance resistance according to the following formula: in order to achieve high signal voltage: Rres should be high in order to achieve low antenna noise voltage: Rres should be low Rres < 200 k: the input noise voltage of A 1 dominates Rres > 300 k: the antenna noise voltage dominates That means the resonant resistance should be between 200 k and 300 k R res Q of antenna must be high for attenuation of interfering signals. But the temperature must not influence the resonance frequency. Design Hints for the Ferrite Antenna The bar antenna is the most critical device of the complete clock receiver. But by observing some basic rf design knowledge, no problem should arise with this part. The IC requires a resonance resistance of 200 k to 300 k. This can be achieved by a variation of the L/C-relation in the antenna circuit. But it is not easy to measure such high resistances in the RF region. It is much more convenient to distinguish the bandwidth of the antenna circuit and afterwards to calculate the resonance resistance. Thus the first step in designing the antenna circuit is to measure the bandwidth. Figure 4 shows an example for the test circuit. The RF signal is coupled into the bar antenna by inductive means, e.g. a wire loop. It can be measured by a simple oscilloscope using the 10:1 probe. The input capacitance of the probe, typically about 10 pF, should be taken into consideration. By varying the frequency of the signal generator, the resonance frequency can be determined. RF - Signal generator 77.5 kHz Scope Probe w1010 M: 1 wire loop Cres 94 7907 e Afterwards, the two frequencies where the voltage of the rf signal at the probe drops 3 dB down can be measured. The difference between these two frequencies is called the bandwidth BWA of the antenna circuit. As the value of the capacitor Cres in the antenna circuit is well known, 1 + 2 @ @ BW @C A res whereas Rres is the resonance resistance, BWA is the measured bandwidth (in Hz) Cres is the value of the capacitor in the antenna circuit (in Farad) If high inductance values and low capacitor values are used, the additional parasitic capacitances of the coil must be considered. It may reach up to about 20 pF. The Q-value of the capacitor should be no problem if a high Q-type is used. The Q-value of the coil is more or less distinguished by the simple DC-resistance of the wire. Skin effects can be observed but do not dominate. Therefore it should be no problem to achieve the recommended values of resonance resistance. The use of thicker wire increases Q and accordingly reduces bandwidth. This is advantageous in order to improve reception in noisy areas. On the other hand, temperature compensation of the resonance frequency might become a problem if the bandwidth of the antenna circuit is low compared to the temperature variation of the resonance frequency. Of course, Q can also be reduced by a parallel resistor. Temperature compensation of the resonance frequency is a must if the clock is used at different temperatures. Please ask your dealer of bar antenna material and of capacitors for specified values of temperature coefficient. Furthermore some critical parasitics have to be considered. These are shortened loops (e.g. in the ground line of the PCB board) close to the antenna and undesired loops in the antenna circuit. Shortened loops decrease Q of the circuit. They have the same effect like conducting plates close to the antenna. To avoid undesired loops in the antenna circuit it is recommended to mount the capacitor Cres as close as possible to the antenna coil or to use a twisted wire for the antenna coil connection. This twisted line is also necessary to reduce feedback of noise from the microprocessor to the IC input. Long connection lines must be shielded. For the adjustment of the resonance frequency the capacitance of the probe and the input capacitance of the IC are to be taken into account. The alignment should be done in the final environment. The bandwidth is so low that metal parts close to the antenna influence the resonance frequency. The adjustment can be done by pushing the coil along the bar antenna. 4 (12) Preliminary Information TELEFUNKEN Semiconductors Rev. A1, 15-May-96 U4221B Absolute Maximum Ratings Parameters Supply voltage Ambient temperature range Storage temperature range Junction temperature Electrostatic handling ( MIL Standard 883°C) Symbol VCC Tamb Rstg Tj ± VESD Value 5.5 –20 to +70 –30 to +85 125 2000 Unit V _C _C _C V Symbol RthJA Value 70 Unit K/W Thermal Resistance Parameters Thermal resistance Electrical Characteristics VCCA, VCCD = 3.0 V, reference point Pins 3, 7, 15, input signal according to DCF 77 transmitter, Tamb = 25_C, unless otherwise specified Parameters Supply voltage range Supply current ICC = ICCA + ICCD Reception frequency range Minimum input voltage Maximum input voltage Test Conditions / Pins Pins 9, 16 Pins 9, 16 without reception signal with reception signal > 20 mV OFF-mode Rgen = 50 W Pins 1,2 Rres 300 kW, Qres > 30 Rgen = 50 W Pins 1,2 Rres 300 kW, Qres > 30 Pins 1, 2 v v Input capacitances to ground Set-up time after POWER ON TIMING CODE OUTPUT; TCO Pin 13 Output voltage RLOAD = 13 MW to GND HIGH RLOAD = 2.6 MW to VCCD LOW Output current VTCO = VCCD/2 HIGH VTCO = VCCD/2 LOW Decoding characteristics input carrier reduction 100 ms input carrier reduction 200 ms POWER ON/OFF CONTROL; PON Pin 14 Input voltage Generator output resistance HIGH 200 kW LOW v TELEFUNKEN Semiconductors Rev. A1, 15-May-96 Symbol VCCA VCCD ICC Min. 2.4 fin Vin 60 Vin 40 Typ. 1.5 Cin 1 Cin 2 tpon Max. 5.5 40 35 0.2 80 1.75 Unit V mA mA mA kHz mV mV 1 1 2.5 pF 5 s 0.4 V V VOH VOL VCCD-0.4 ISOURCE ISINK 0.2 1 0.4 4 mA mA t100 t200 50 150 110 230 ms ms 0.4 V V VCCD–0.4 5 (12) Preliminary Information U4221B Electrical Characteristics Parameters Test Conditions / Pins FIELD STRENGTH INDICATION; FSI Pin 12 Output voltage RLOAD = 13 M to GND HIGH RLOAD = 2.6 M to VCCD LOW Output current VTCO = VCCD/2 HIGH VTCO = VCCD/2 LOW FIELD STRENGTH SELECT; FSS Pin 11 Input voltage Generator output resistance HIGH 200 k LOW Symbol Min. Typ. Max. VCC–0.4 Unit V 0.4 0.2 1.0 v 0.4 4.0 VCC–0.4 0.4 V V Test Circuit for DCF +VCC Measurement point 1 16 2 15 3 14 4 13 77,5 kHz Generator 100 n 50 k 220 n 100 (with variable output level) PON TCO U 4221 B 5 Modulation depth adjustment by potentiometer (carrier reduced to 25%) Electronic switch (Time Code) T 1s It must be noted: Input is shortened by 50 that means, the antenna noise is not taken into consideration. w 12 47 n 6 11 7 10 8 9 VCCD–0.8 V Measuring device: Oscilloscope with high impedance probe ( 20 M) w 77.5 kHz T = 100 ms (binary “0”) or 200 ms (binary “1”) Receiver input signal calibration: Example: 2 Veff input signal ⇒ 2 2 2 103 = 5.65 mVpp at measurement point 6 (12) Preliminary Information 93 7719 e TELEFUNKEN Semiconductors Rev. A1, 15-May-96 U4221B Application Circuit for DCF 77.5 kHz +V Ferrite Antenna 1 16 2 15 3 14 4 13 CONTROL LINES CC PON 220 nF TCO MICROCOMPUTER U 4221 B 47 nF KEYBOARD 5 12 6 11 7 10 8 9 DISPLAY 77.5 kHz 93 7504 e Application Circuit for WWVB 60 kHz +V Ferrite Antenna 1 16 2 15 3 14 4 13 CONTROL LINES CC PON 220 nF TCO MICROCOMPUTER U 4221 B 47 nF KEYBOARD 5 12 6 11 7 10 8 9 DISPLAY 60 kHz 94 7906 e TELEFUNKEN Semiconductors Rev. A1, 15-May-96 7 (12) Preliminary Information U4221B Information Regarding German Transmitter Station: DCF 77, Frequency 77.5 kHz, Transmitting power 50 kW Location: Mainflingen/Germany, Geographical coordinates: 50_ 0.1’N, 09 00’E Time of transmission: permanent Time Frame 1 Minute Time Frame ( index count 1 second ) 10 5 20 15 25 40 35 30 45 55 50 0 5 10 R A1 Z1 Z2 A2 S 1 2 4 8 10 20 40 P1 1 2 4 8 10 20 P2 1 2 4 8 10 20 1 2 4 1 2 4 8 10 1 2 4 8 10 20 40 80 P3 0 minutes coding when required Example:19.35 h 1 s sec. 20 21 2 22 4 23 10 8 24 25 26 calendar day month day of the week hours 20 40 27 P1 28 29 2 1 30 31 The carrier amplitude is reduced to 25% at the beginning of each second for 100 ms (binary zero) or 200 ms (binary one) duration, excepting the 59th second. Time Code Format: (based on information of Deutsche Bundespost) It consists of 1 minute time frames. No modulation at the beginning of the 59th second to recognize the switch over 8 32 10 33 20 34 P2 35 hours Parity Bit P1 Modulation: 93 7527 4 minutes Start Bit year Parity Bit P2 to the next 1 minute time frame. A time frame contains BCD-coded information of minutes, hours, calendar day, day of the week, month and year between the 20th second and 58th second of the time frame, including the start bit S (200 ms) and parity bits P1, P2 and P3. Further there are 4 additional bits R (transmission by reserve antenna), A1 (announcement of change-over to the summer time), Z1 (during the summer time 200 ms, otherwise 100 ms), Z2 (during standard time 200 ms otherwise 100 ms) and A2 (announcement of leap second) transmitted between the 15th second and 19th second of the time frame. 8 (12) Preliminary Information TELEFUNKEN Semiconductors Rev. A1, 15-May-96 U4221B Information Regarding British Transmitter Geographical coordinates: 52_ 22’N, 01 11’W Time of transmission: permanent, excepting the first Tuesday of each month from 10.00 h to 14.00 h. Station: MSF Frequency 60 kHz Transmitting power 50 kW Location: Teddington, Middlesex TIME FRAME 1 MINUTE TIME FRAME ( index count 1 second) 10 5 15 20 25 35 30 50 45 40 55 0 year month switch over to the next time frame day of hour month day of week minute 10 minute identifier BST hour + minute day of week day + month year BST 7 GMT change impending Parity check bits 1 0 5 0 80 40 20 10 8 4 2 1 10 8 4 2 1 20 10 8 4 2 1 4 2 1 20 10 8 4 2 1 40 20 10 8 4 2 1 0 0 500 ms 500 ms 93 7528 Example: March 1993 seconds 17 80 18 40 19 20 8 10 20 21 4 22 2 23 10 1 24 25 26 year Modulation: 4 27 1 2 28 29 30 month Time Code Format: The carrier amplitude is reduced at the beginning of each second for the time of 100 ms (binary zero) or 200 ms (binary one). TELEFUNKEN Semiconductors Rev. A1, 15-May-96 8 It consists of 1 minute time frames. A time frame contains BCD-coded information of year, month, calendar day, day of the week, hours and minutes. At the switch-over to the next time frame, the carrier amplitude is reduced for 500 ms duration. 9 (12) Preliminary Information U4221B Information Regarding US Transmitter Station: WWVB Frequency 60 kHz Transmitting power 10 kW Location: Fort Collins Geographical coordinates: 40_ 40’N, 105 03’W Time of transmission: permanent. TIME FRAME 1 MINUTE TIME FRAME ( index count 1 second) 45 50 55 0 5 10 P0 80 40 20 10 P5 8 4 2 1 40 ADD SUB ADD P4 800 400 200 100 80 40 20 10 P3 8 4 2 1 days hours minutes 35 30 25 200 100 20 8 4 2 1 P2 15 20 10 P0 FRM 40 20 10 10 8 4 2 1 P1 5 0 daylight savings time bits leap second warning bit leap year indicator bit ”0” = non leap year ”1” = leap year UTI UTI year sign correction 93 7529 e Example: UTC 18.42 h TIME FRAME P0 seconds0 40 20 10 1 2 3 4 8 5 4 6 2 7 1 8 P1 20 10 8 4 2 1 P2 9 10 11 12 13 14 15 16 17 18 19 20 minutes Frame reference marker hours Modulation: Time Code Format: The carrier amplitude is reduced at the beginning of each second and is restored in 500 ms (binary one) or in 200 ms (binary zero). It consists of 1 minute time frames. A time frame contains BCD-coded information of minutes, hours, days and year. In addition there are 6 position identifier markers (P0 thru P5) and 1 frame reference marker with reduced carrier amplitude of 800 ms duration. 10 (12) Preliminary Information TELEFUNKEN Semiconductors Rev. A1, 15-May-96 U4221B Ordering and Package Information Extended Type Number U4221B-BFP U4221B-BFPG1 Package SO16 plastic SO16 plastic Remarks Taping according to IEC-286-3 Package: SO16 TELEFUNKEN Semiconductors Rev. A1, 15-May-96 11 (12) Preliminary Information U4221B Ozone Depleting Substances Policy Statement It is the policy of TEMIC TELEFUNKEN microelectronic GmbH to 1. Meet all present and future national and international statutory requirements. 2. Regularly and continuously improve the performance of our products, processes, distribution and operating systems with respect to their impact on the health and safety of our employees and the public, as well as their impact on the environment. It is particular concern to control or eliminate releases of those substances into the atmosphere which are known as ozone depleting substances ( ODSs). The Montreal Protocol ( 1987) and its London Amendments ( 1990) intend to severely restrict the use of ODSs and forbid their use within the next ten years. Various national and international initiatives are pressing for an earlier ban on these substances. TEMIC TELEFUNKEN microelectronic GmbH semiconductor division has been able to use its policy of continuous improvements to eliminate the use of ODSs listed in the following documents. 1. Annex A, B and list of transitional substances of the Montreal Protocol and the London Amendments respectively 2 . Class I and II ozone depleting substances in the Clean Air Act Amendments of 1990 by the Environmental Protection Agency ( EPA) in the USA 3. Council Decision 88/540/EEC and 91/690/EEC Annex A, B and C ( transitional substances ) respectively. TEMIC can certify that our semiconductors are not manufactured with ozone depleting substances and do not contain such substances. We reserve the right to make changes to improve technical design and may do so without further notice. Parameters can vary in different applications. All operating parameters must be validated for each customer application by the customer. Should the buyer use TEMIC products for any unintended or unauthorized application, the buyer shall indemnify TEMIC against all claims, costs, damages, and expenses, arising out of, directly or indirectly, any claim of personal damage, injury or death associated with such unintended or unauthorized use. TEMIC TELEFUNKEN microelectronic GmbH, P.O.B. 3535, D-74025 Heilbronn, Germany Telephone: 49 ( 0 ) 7131 67 2831, Fax number: 49 ( 0 ) 7131 67 2423 12 (12) Preliminary Information TELEFUNKEN Semiconductors Rev. A1, 15-May-96