Features • • • • • • • • • • • • • FM Double-conversion System Integrated Second IF Filter with Software-controlled Bandwidth Completely Integrated FM Demodulator Soft Mute and Multipath Noise Cancellation Receiving Condition Analyzer AM Up/Down-conversion System AM Preamplifier with AGC and Stereo Capability 3-wire Bus Controlled Search Stop Signal Generation (AM and FM) Automatic Alignment Possible Pin Compatible with ATR4255 World Tuner, US Weatherboard, J-band Lead-free Package AM/FM Receiver IC ATR4258 Electrostatic sensitive device. Observe precautions for handling. Description The ATR4258 is a highly integrated AM/FM front-end circuit manufactured using Atmel’s advanced BICMOS technology. It represents a complete, automatically adjustable AM/FM front end, containing a double-conversion system for FM and an up/down-conversion receiver for AM with IF1 = 10.7 MHz and IF2 = 450 kHz. The front end is suitable for digital or analog AF-signal processing. Together with the PLL U4256BM, an automatically aligned high-performance AM/FM tuner can be built. These ICs are dedicated for highly sophisticated car radio applications. Rev. 4838A–AUDR–10/04 Figure 1. Block Diagram IF1FMI MX1OA MX1OB 43 44 IF1AMI IF1REF 38 39 V3 MX2OB IF1OUT MX2IN 33 30 29 26 MX2OA 24 23 IF2IN V3P 28 27 AM AM Dem. OPLPF 32 FM 41 AGC MX1AMA MX1AMB AMAGC AMVREG AMPLPF V3 7 6 8 35 AGC 1 IFAGCH 20 Automatic FILADJ Adjustment 37 FM MX1FMB MultiMULTIP path 40 2 GNDMX IFAGCL IF2OUT Noiseblanker AGC MX1FMA 36 AM 3 4 Divider 2...10 OSCOUT 16 Offset Adj. Chan. FM Dem. Stop Soft Mute MPX 11 Divider GNDOSC OSCE OSCB 15 14 13 V3 OSC Bandgap 12 25 42 Bus 5 17 18 19 V57 VS EN DATA GND FMAGC CLK 2 Dev. Ana. INT 9 METER 22 MX2LO 10 ADJAC 21 INT 34 SMUTE 31 DEV ATR4258 4838A–AUDR–10/04 ATR4258 Pin Configuration Figure 2. Pinning SSO44 MX1FMA 1 44 MX1OB MX1FMB 2 43 MX1OA MX1AMB 3 42 VS GNDMX 4 41 MX1AMA FMAGC 5 40 MULTIP AMVREG 6 39 IF1REF AMAGC 7 38 IF1FMI AMPLPF 8 37 FILADJ METER 9 36 IFAGCL ADJAC 10 35 IFAGCH MPX 11 34 SMUTE V57 12 33 IF1AMI OSCB 13 32 OPLPF OSCE 14 31 DEV GNDOSC 15 30 IF1OUT OSCOUT 16 29 V3 EN 17 28 IF2IN CLK 18 27 V3P DATA 19 26 MX2IN IF2OUT 20 25 GND INT 21 24 MX2OA MX2LO 22 23 MX2OB 3 4838A–AUDR–10/04 Pin Description 4 Pin Symbol Function 1 MX1FMA 1st mixer FM input A 2 MX1FMB 1st mixer FM input B 3 MX1AMB 1st mixer AM input B 4 GNDMX Ground 1st mixer, preamplifier AGC 5 FMAGC FM preamplifier AGC 6 AMVREG 7 AMAGC AM preamplifier AGC 8 AMPLPF AM AGC LP filter AM control voltage 9 METER Field strength output 10 ADJAC Adjacent channel detection output 11 MPX Multiplex signal 12 V57 5.7 V reference voltage 13 OSCB Oscillator basis 14 OSCE Oscillator emitter 15 GNDOSC Oscillator ground 16 OSCOUT Oscillator output 17 EN 3-wire bus enable 18 CLK 3-wire bus clock 19 DATA 3-wire bus data 20 IF2OUT 2nd IF amplifier output 21 INT Interrupt, stop signal 22 MX2LO 10.25 MHz input for 2nd mixer 23 MX2OB 2nd mixer output B 24 MX2OA 2nd mixer output A 25 GND 26 MX2IN Ground 2nd mixer input 27 V3P 3 V reference for AMPIN, AMIFAGC, Control, IF2IN 28 IF2IN 2nd IF amplifier input 29 V3 30 IF1OUT 3 V reference for IF1OUT, MX2IN 1st IF amplifier output 31 DEV 32 OPLPF Operating point LPF Deviation detect output, test output 33 IF1AMI 1st IF AM amplifier input 34 SMUTE Soft MUTE control input 35 IFAGCH IF AGC LP filter high time 36 IFAGCL IF AGC LP filter low time constant 37 FILADJ Filter adjust 38 IF1FMI 1st IF FM amplifier input 39 IF1REF 1st IF & MX1OUT reference, MX1AM A, MX1AM B 40 MULTIP Multipath detection output 41 MX1AMA 42 VS 43 MX1OA 1st mixer output A 44 MX1OB 1st mixer output B 1st mixer AM input A Supply voltage ATR4258 4838A–AUDR–10/04 ATR4258 Functional Description The ATR4258 implements an AM up/down-conversion reception path from the RF input signal to the AM-demodulated audio frequency output signal, and for FM/WB reception a double-conversion reception path from the RF input signal to the FM-demodulated multiplex signal (MPX). A VCO and an LO prescaler for AM are integrated to generate the LO frequency for the 1st mixer. Automatic gain control (AGC) circuits are implemented to control the preamplifier and IF stages in the AM and FM reception path. For improved FM performance, an integrated IF filter with adjustable bandwidth, a softmute feature and an automatic multipath noise cancellation (MNC) circuit are fully integrated. A powerful set of sensors is provided for receiving condition analysis and stop signal generation. Several register bits (bit 0 to bit 93) are used to control circuit operation and to adapt certain circuit parameters to the specific application. The control bits are organized in two 8-bit and three 24-bit registers that can be programmed by the 3-wire bus protocol. The bus protocol and the bit-to-register mapping is described in the section “3-wire Bus Description” on page 20. The meaning of the control bits is mentioned in the following sections. The integrated VCO has a high frequency range. Additionally the VCO has a special VCO divider which allows (in connection with the VCO) the reception of all analog world bands. Reception Mode The IC can be operated in four different modes. Mode AM, FM, WB, and Standby are selected by means of bit 92 and bit 93 according to Table 1 on page 6. Additionally to the operating modes, the signal paths can be set separately. Bit 62 selects the first mixer and AGC, bit 63 selects the 1st amplifier stage. The recommended settings of bit 62 and bit 63 are included in Table 1 on page 6. In AM mode the AM mixer, the AM RF-AGC and the 1st IF AM amplifier at pin 33 are activated. The input of the 2nd IF amplifier is connected to pin 28 and the output of the 2nd IF amplifier is fed to the AM demodulator. The output of the AM demodulator is available at MPX output pin 11. In FM mode the FM mixer, the FM RF-AGC and the 1st IF FM amplifier at pin 38 are activated. The bandwidth of the output tank at pin 23, pin 24 is increased and the input of the 2nd IF amplifier can be switched between pin 23 and pin 24 and pin 28. The output of the 2nd IF amplifier is fed to the integrated band filter and FM demodulator. The output of the FM demodulator is available at MPX output pin 11. The WB mode is similar to the FM mode, but to reduce the bandwidth the AM IF amplifier with the AM filter (bit 63 = 1) can be used. In WB mode the range of the integrated filter bandwidth control is shifted to lower bandwidth and the gain of the FM demodulator is increased. In standby mode the mixers, IF amplifiers and AGC circuits are deactivated to reduce current consumption. 5 4838A–AUDR–10/04 Table 1. Operating Mode Test Mode AM/FM/Weather Channel Bit 93 Bit 92 Bit 63 Bit 62 Standby 0 0 X X FM 0 1 0 0 AM 1 0 1 1 Weather band 1 1 1 0 A special test mode is implemented for final production test only. This mode is activated by setting bit 9 = 1. This mode is not intended to be used in customer applications. For normal operation, bit 9 has to be set to 0. Bit 22 to bit 30 are deactivated in normal operation mode. Table 2. Test Mode VCO/Local Oscillator Prescaler Mode Bit 9 Normal operation 0 Test mode 1 An oscillator circuit is implemented to build a VCO as proposed in the application schematic. The VCO frequency is used to generate the LO frequency of the 1st mixer stages. The control voltage of the VCO is usually generated by the PLL circuit U4256BM. The VCO frequency has a range of 70 MHZ to 250 MHz to allow the reception of all analog world bands. A main element of the implemented oscillator circuit is a bipolar NPN transistor. The internally biased base is connected to pin 13 and the emitter to pin 14. An AGC circuit (bit 30) can be activated to increase the emitter current until the appropriate oscillation level is reached. The fundamental emitter current can be changed by bit 52. Table 3. Local Oscillator AGC Local Oscillator (VCO) Bit 30 AGC off (default) 0 AGC on 1 Table 4. Local Oscillator Gain Local Oscillator (VCO) Bit 52 Low Gain 0 High Gain 1 In addition (to the AM prescaler) a special VCO prescaler is implemented for all modes (AM, WB and FM). The divider factor of the prescaler buffer provides the signal of the buffered output (at pin 16) and the prescaler VCO provides the signal of the 1st FM mixer stage and AM prescaler. Examples of VCO prescaler settings are described in section “Application Information” on page 29. The divider factor of the VCO and buffer prescaler can be selected according Table 5 on page 7. 6 ATR4258 4838A–AUDR–10/04 ATR4258 Table 5. Local Oscillator Prescaler (VCO/Buffer Divider) Prescaler VCO Prescaler Buffer Bit 12 Bit 11 Bit 10 1 1 X 0 0 1.5 3 0 0 1 1.5 1.5 1 0 1 2 2 X 1 0 3 3 X 1 1 Note: FM RF-AGC The U4256 FMOSCIN (pin 19) input frequency is limited to 160 MHz. The FM RF-AGC circuit includes a wide-band level detector at the input pin 1 of the FM mixer and an in-band level detector at the output of the FM IF amplifier (pin 30). The outputs of these level detectors are used to control the current into the pin diode (see Figure 3) in order to limit the signal level at the FM mixer input and the following stages. The maximum pin diode current is determined by R115 and the time constant of the AGC control loop can be adjusted by changing the value of C111. The AGC threshold level at the input of the FM mixer can be adjusted by bit 64 and bit 65 according to Table 6. The in-band AGC threshold refers to the FM mixer input (pin 1, pin 2) depends on the gain of the FM IF amplifier and can be adjusted by bit 89 to bit 91. Table 6. FM-AGC Threshold FM-AGC Threshold Bit 65 Bit 64 100 dBµV 0 0 97 dBµV 0 1 94 dBµV 1 0 91 dBµV 1 1 Figure 3. FM RF-AGC Bit 92 VS Pin 42 C111 R115 Pin 5 PIN Diode AGC B92 7 4838A–AUDR–10/04 AM RF-AGC The AM RF-AGC controls the current into the AM pin diodes (pin 7) and the source drain voltage of the MOSFET in the AM preamplifier stage (pin 6) to limit the level at the AM mixer input (pin 3, pin 41). This threshold level can be set by bit 64 and bit 65. If the level at the AM mixer input exceeds the selected threshold, the current into the AM pin diodes is increased. If this step is not sufficient, the source drain voltage of the MOSFET is decreased. The time constant of the AGC control loop can be adjusted by changing the value of the capacitor at pin 8. Table 7. AM-AGC Threshold AM-AGC Threshold Bit 65 Bit 64 91 dBµV 0 0 94 dBµV 0 1 97 dBµV 1 0 100 dBµV 1 1 FM 1st Mixer In the 1st FM mixer stage, the FM reception frequency is down converted to the 1st IF frequency. The VCO frequency is used as LO frequency for the mixer. AM 1st Mixer The AM 1st mixer is used for up-conversion of the AM reception frequency to the 1st IF frequency. Therefore, an AM prescaler is implemented to generate the necessary LO frequency from the VCO frequency. The divide factor of the AM prescaler can be selected according to Table 8. (The AM prescaler is only active in AM mode). Table 8. Divide Factor of the AM Prescaler 8 Divider (AM Prescaler) Bit 93 Bit 92 Bit 84 Bit 83 Bit 82 Bit 81 Divide by 2 1 0 0 0 0 0 Divide by 3 1 0 0 0 0 1 Divide by 4 1 0 0 0 1 0 Divide by 5 1 0 0 0 1 1 Divide by 6 1 0 0 1 0 0 Divide by 7 1 0 0 1 0 1 Divide by 8 1 0 0 1 1 0 Divide by 9 1 0 0 1 1 1 Divide by 10 1 0 1 X X X ATR4258 4838A–AUDR–10/04 ATR4258 FM 1st IF Amplifier A programmable gain amplifier is used in FM (and WB) mode between pin 38 and pin 30 to compensate the loss in the external ceramic band filters. The gain of this amplifier is adjusted by bit 89 to bit 91. The input and the output resistance is 330 Ω and fits to external ceramic filters. Two different temperature coefficients of the FM IF amplifier can be selected by bit 66. Table 9. Gain of the FM IF Amplifier Gain FM IF Bit 91 Bit 90 Bit 89 19 dB 0 0 0 21 dB 0 0 1 23 dB 0 1 0 25 dB 0 1 1 27 dB 1 0 0 28 dB 1 0 1 29 dB 1 1 0 30 dB 1 1 1 Table 10. Temperature Coefficient Setting of FM IF Amplifier Temperature Coefficient (TC) of the IF Amplifier Bit 66 TKmin (TK 1) 0 TKmax (TK 2) 1 AM 1st IF Amplifier In AM and WB mode, the gain of the 1st IF amplifier is controlled by the IF-AGC to extend the control range of the IF-AGC. 2nd Mixer The 2nd mixer is used in AM, FM and WB mode. The mixer input has 330 Ω input resistance and can be connected directly to an external ceramic filter. In FM mode, the high output resistance of the second mixer is reduced to increase the bandwidth of the tank at the mixer output. The output resistance can be selected by bit 60 and bit 61. In AM and WB mode bit 61 and bit 62 should be set to 0. Table 11. 2nd Mixer Output Resistance in FM Mode Bit 61 Bit 60 Output Resistance (Bit 54 = 0) Output Resistance (Bit 54 = 1) 0 0 3.3 kΩ ~100 kΩ 0 1 0.63 kΩ 0.78 kΩ 1 0 0.47 kΩ 0.55 kΩ 1 1 0.29 kΩ 0.32 kΩ The LO frequency of the 2nd mixer (10.25 MHz) has to be applied at pin 22. This signal is usually generated by the PLL circuit U4256BM. 9 4838A–AUDR–10/04 Table 12. FM Bandwidth Mixer 2 Bit 61 Bit 60 FM Bandwidth Mixer 2 0 0 150 kHz 0 1 200 kHz 1 0 250 kHz 1 1 450 kHz Note: 2nd IF Amplifier The bandwidth is also dependant on the values of the application circuit. In AM and WB mode, the input of the second IF amplifier is pin 28, is externally connected to the 2nd mixer tank through the AM ceramic filter to achieve channel selectivity. During normal FM operation (bit 54 = 0), the input of the second IF amplifier is connected to the 2nd mixer output (pin 23, pin 24) and the integrated FM band filter is used for channel selectivity only. It is possible to use an additional external filter between the 2nd mixer tank and pin 28 in FM mode by setting bit 54 to 1. Table 13. 2nd IF Filter in FM Mode 2nd IF Filter Bit 54 Internal filter 0 External and internal filter 1 The IF-AGC controls the level of the 2nd IF signal that is passed to the AM demodulator input or the integrated FM band filter and to the 2nd IF output, pin 20. IF-AGC Two different time constants of the IF-AGC can be selected by the capacitors at pin 35 (IFAGCH) and pin 36 (IFAGCL). The short time constant (IFAGCL) is used in FM/WB mode and in AM search mode. The long time constant (IFAGCH) is used for AM reception. Table 14. IF-AGC Time Constant Mode Bit 92 Bit 88 IF AGC Time Constant FM/WB 1 X IFAGCL (fast) AM reception 0 0 IFAGCH (slow) AM search 0 1 IFAGCL (fast) In FM/WB mode, the output signal of the FM demodulator is applied to pin 35 via a series resistor of about 95 kΩ. This low-pass filtered output signal of the FM demodulator is used for the FM demodulator fine adjustment, for muting and as a reference for the deviation sensor. 10 ATR4258 4838A–AUDR–10/04 ATR4258 2nd IF Output The 2nd IF after the gain-controlled 2nd IF amplifier is available at pin 20 (bit 55 = 0). In AM mode, this signal may be used for an external AM stereo decoder. Alternatively, a signal corresponding to the logarithmic field strength after the integrated FM band filter, which is used for multipath detection, can be switched to pin 20 by setting bit 55 = 1. Table 15. Pin 20 Output Setting Pin 20 nd 2 Bit 55 IF output 0 Multipath field strength Automatic IF Center Frequency Adjustment 1 Integrated active filters are used in the FM band filter, FM demodulator and adjacent channel sensor. The center frequency of these filters is automatically adjusted to the second IF frequency of 450 kHz. The frequency of 10.25 MHz at pin 22 is used as a reference for this alignment. Figure 4. Automatic IF Center Frequency Adjustment Pin 22 10.25 MHz Automatic frequency adjustment Bit 56...59 Center frequency Center frequency Bit 14...17 FM-Demod FMband filter Pin 37 For fine tuning, the center frequency of all these integrated active filters (band filter and demodulator) can be shifted in steps of 6.25 kHz by means of bit 56 to bit 59. Additionally, the center frequency of the band filter can be adjusted separately by means of bit 14 to bit 17. 11 4838A–AUDR–10/04 Table 16. 2nd IF Center Frequency IF Center Bit 59 Bit 58 Bit 57 Bit 56 450.00 kHz 0 0 0 0 456.25 kHz 0 0 0 1 462.50 kHz 0 0 1 0 468.75 kHz 0 0 1 1 475.00 kHz 0 1 0 0 481.25 kHz 0 1 0 1 487.50 kHz 0 1 1 0 493.75 kHz 0 1 1 1 450.00 kHz 1 0 0 0 443.75 kHz 1 0 0 1 437.50 kHz 1 0 1 0 431.25 kHz 1 0 1 1 425.00 kHz 1 1 0 0 418.75 kHz 1 1 0 1 412.50 kHz 1 1 1 0 406.25 kHz 1 1 1 1 Table 17. FM Band Filter Center Frequency Correction 12 IF Correction Bit 17 Bit 16 Bit 15 Bit 14 -0 kHz 0 0 0 0 -6.25 kHz 0 0 0 1 -12.50 kHz 0 0 1 0 -18.75 kHz 0 0 1 1 -25.00 kHz 0 1 0 0 -31.25 kHz 0 1 0 1 -37.50 kHz 0 1 1 0 -43.75 kHz 0 1 1 1 +0 kHz (default) 1 0 0 0 +6.25 kHz 1 0 0 1 +12.50 kHz 1 0 1 0 +18.75 kHz 1 0 1 1 +25.00 kHz 1 1 0 0 +31.25 kHz 1 1 0 1 +37.50 kHz 1 1 1 0 +43.75 kHz 1 1 1 1 ATR4258 4838A–AUDR–10/04 ATR4258 Integrated FM Band Filter For FM reception a band filter with variable bandwidth is integrated in front of the demodulator to provide channel selectivity on the 2nd IF. The bandwidth of this filter can be adjusted by bit 0 to 3 (see Table 18) to be suitable for the present receiving condition. In WB mode, the bandwidth of the integrated filter is shifted to lower bandwidth values, while the necessary channel selectivity is achieved by an external ceramic filter. The center frequency of the integrated FM band filter can be adjusted by means of bit 14 to 17. The field strength after the integrated FM band filter that is available at pin 20 (bit 55 = 1) can be used for this purpose. Table 18. Bandwidth of the Integrated Band Filter FM Demodulator IF Bandwidth FM IF Bandwidth WB Bit 3 Bit 2 Bit 1 Bit 0 220 195 0 0 0 0 ... ... ... ... ... ... 200 160 0 0 1 1 ... ... ... ... ... ... 165 120 0 1 1 0 ... ... ... ... ... ... 130 80 1 0 0 1 ... ... ... ... ... ... 80 35 1 1 0 1 70 – 1 1 1 0 60 – 1 1 1 1 For weather band reception, the gain of the FM demodulator is increased and can be adjusted by means of bit 71 and bit 72 in order to increase the output voltage to compensate the low frequency deviation in weather band. An integrated demodulator fine adjustment allows automatic fine tuning of the demodulator center frequency to the average frequency of the received signal. This feature is implemented for use in weather band mode and can be activated by setting bit 53 to 0. Figure 5. FM Demodulator Automatic Fine Tuning MPX (Pin 11) FM Demod Center freq. AM AGC B92 IFAGCH (Pin 35) + Bit 53 V3P (Pin 27) Automatic frequency adjustment 13 4838A–AUDR–10/04 The center frequency of the FM demodulator can be adjusted by means of bit 56 to 59. At the center frequency, the DC voltage at the MPX output pin 11 is equal to the MPX offset voltage that can be measured at pin 11 while MPX mute is active (bit 7 = 1). This adjustment will affect the center frequency of all integrated filters as mentioned before. Table 19. Demodulator Gain in Weather Band Mode Demodulator Gain in Weather Band Mode Relative to FM Mode Bit 72 Bit 71 14 dB 0 0 17 dB 0 1 21 dB 1 0 23 dB 1 1 Table 20. Demodulator Fine Adjustment Soft Mute Demodulator Fine Adjustment Bit 53 Fine tuning ON 0 Fine tuning OFF 1 The soft mute functionality is implemented to reduce the output level of the FM demodulator at low input signal levels to limit the noise at the MPX output in this case. If the input level falls below an adjustable threshold continuously, the output of the FM demodulator is continuously muted with decreasing input level until a maximum mute value is reached. The threshold for the start of soft mute and the maximum mute can be adjusted. The signal level for 3 dB mute can be set by means of bit 68 to bit 70 and the maximum value for soft mute can be selected by bit 67. The steepness and the time constant of the soft mute can be adjusted by the resistor and capacitor between pin 34 and pin 29. The field strength signal available at pin 9 is used for soft mute. Therefore, the soft mute threshold that referred to the input of the FM mixer depends on the gain from the FM mixer input to the field strength sensor and on the setting of field strength offset (bit 15 to bit 21). Table 21. Soft Mute Threshold 14 Relative Soft Mute Threshold Bit 70 Bit 69 Bit 68 Soft mute OFF 0 0 0 -18 dB 0 0 1 -15 dB 0 1 0 -12 dB 0 1 1 -9 dB 1 0 0 -6 dB 1 0 1 -3 dB 1 1 0 0 dB 1 1 1 ATR4258 4838A–AUDR–10/04 ATR4258 Table 22. Maximum Soft Mute Maximum Value of Soft Mute Bit 67 30 dB 0 26 dB 1 Figure 6. Soft Mute + FS (pin 9) Bit 67 Pin 34 Gain FM demodulator Bits 68 to 70 Pin 29 MPX Output V3 The output of the AM demodulator (AM mode) or the output of the FM demodulator (FM/WB mode) are available at the MPX output (pin 11). The MPX output signal can be muted by setting bit 7 to 1. The bandwidth of the low-pass filter at the MPX output can be set by means of bit 79 to 90 kHz or 180 kHz. Table 23. MPX Output Mute MPX Output Bit 7 MPX out, pin 11 normal operation 0 Mute ON 1 Table 24. MPX Output Bandwidth Receiving Condition Analyzer Bandwidth MPX Low-pass Filter Bit 79 90 kHz 0 180 kHz 1 The ATR4258 implements several sensors that provide information about the receiving condition of the selected station. 15 4838A–AUDR–10/04 Field Strength Sensor The field strength sensor provides a DC voltage at pin 9 which represents the logarithmic field strength of the signal in the reception band. The field strength information can be retrieved either from a level detector at the input of the 2nd mixer (pin 26) or from the IF-AGC depending on the setting of bit 80. The bandwidth of the field strength detection in the AGC is smaller than by using the level detector because of additional selectivity between the 2nd mixer and the 2nd IF amplifier particularly in AM and WB, but the field strength detection in the AGC is limited to the IF AGC range. Usually the field strength from the level detector is used in FM/WB mode and the AGC field strength is used in AM mode. The field strength output at pin 9 can be adjusted by the bits 18 to 21 in 0.5 dB steps. This offset also has an influence on the soft mute levels. Table 25. Field Strength Offset Offset Field Strength Field Strength Selection Bit 21 Bit 20 Bit 19 Bit 18 0.0 dB 0 0 0 0 0.5 dB 0 0 0 1 1.0 dB 0 0 1 0 ... ... ... ... ... 7.5 dB 1 1 1 1 Bit 80 and bit 13 allows the switches between narrow-band field strength and wide-band field strength information. Table 26. Field Strength (Combined) Field Strength (Pin 9) Narrow-band/Wide-band Search Stop Detector Bit 80 Bit 13 FM field strength (wide band) 0 0 Multipath field strength and FM field strength (wide band) 0 1 AM AGC field strength (narrow band) 1 0 Multipath field strength and AM AGC field strength (narrow band) 1 1 A search stop detector is available in AM and FM/WB mode. A STOP condition is signaled (with a low level at pin 21) if the frequency of the IF signal is within a window around the center frequency of 450 kHz. The width of this search stop window can be set by bit 85 to bit 87 in the range of 0.5 kHz to 80 kHz. The frequency of the IF signal is measured by counting the number of periods of the IF signal during a measurement time which is determined by bit 73 to bit 78. The inverted STOP signal is available at pin 21 according to Table 29 on page 17. The frequency of 10.25 MHz at pin 22 is used as a time reference. Table 27. Search Stop Detector Measurement Time Time Window for Stop Signal Bit 78 Bit 77 Bit 76 Bit 75 Bit 74 Bit 73 1 × 3.1969 ms 0 0 0 0 0 1 1 1 1 1 1 1 ..... 63 × 3.1969 ms 16 ATR4258 4838A–AUDR–10/04 ATR4258 Table 28. Search Stop Window Search Stop Window Bit 87 Bit 86 Bit 85 ±0.5 kHz 0 0 0 ±1.1 kHz 0 0 1 ±2.3 kHz 0 1 0 ±4.8 kHz 0 1 1 ±10 kHz 1 0 0 ±20 kHz 1 0 1 ±40 kHz 1 1 0 ±80 kHz 1 1 1 Table 29. Signals Available at Digital Output Pin 21 Note: Bit 88 Bit 92 INT (Pin 21) 0 0 (AM) 1 0 1 (FM/WB) NOT MPINT 1 0 (AM) NOT STOP 1 1 (FM/WB) NOT (STOP AND NOT MPINT) MPINT = Multipath interrupt, Stop and MPINT signal are active low Pin 35 (IFAGCH) is carried along with pin 36 (IFAGCL) to avoid crackles during a change of the search stop mode to the AM reception mode. Deviation Sensor The deviation sensor is active in AM and FM/WB mode and measures the modulation of the signal. It is implemented as a peak detector of the low-pass-filtered MPX signal (see Figure 7). The output voltage at pin 31 is proportional to the frequency deviation in FM/WB or the modulation depth in AM respectively. Figure 7. Deviation Sensor + MPX 4k Pin 31 25k 17 4838A–AUDR–10/04 Adjacent Channel Sensor The adjacent channel sensor is active in FM mode only and measures the field strength outside the reception band. Figure 8. Adjacent Channel Sensor Pin 9 (Meter) IF + SMeter Pin 10 (ADJAC) 30 µA MPINT and ADJAC Reset Bit 6 allows a resets of the multipath sensor and the adjacent channel sensor by connecting pin 10 and pin 40 internally to ground and so the external capacitors can be discharged very quickly. Table 30. Multipath and Adjacent Channel Reset MPINT and Adjacent Channel (Pin 10 and Pin 40) Multipath Sensor Bit 6 Normal mode 0 Connection to ground 1 The multipath sensor is active in FM mode only and measures the disturbance due to multipath reception. The multipath sensor detects drops in the field strength after the integrated band filter by calculating the difference between an averaged maximum field strength and the current field strength. The maximum depth of these drops is represented by the voltage of the peak detector at pin 40 (MULTIP). The level of this voltage represents the degree of disturbance in the received signal. Figure 9. Multipath Sensor + Pin 40 4k 18 ATR4258 4838A–AUDR–10/04 ATR4258 A Multipath Noise Canceller (MNC) is implemented to reduce disturbance of the received signal in multipath reception conditions. If the difference between the momentary and the averaged field strength falls below a threshold adjustable by bit 81 to 84 (see Table 32), the MPX signal may be muted and this situation (MPINT) can be signalized at pin 21 (INT) according to Table 29 on page 17. Muting of the MPX signal during multipath disturbances can be activated be setting bit 8. Table 31. Multipath Noise Canceller Multipath Noise Canceller Bit 8 Active 0 Not active 1 Table 32. Sensitivity of the MNC Note: Sensitivity MNC (Threshold) Bit 84 Bit 83 Bit 82 Bit 81 Off 0 0 0 0 Low 0 0 0 1 ... ... ... ... ... (-33 dB) 0 0 1 1 ... ... ... ... ... Normal (-14 dB) 0 1 1 1 ... ... ... ... ... High (-9 dB) 1 1 1 1 Valid in FM or WB mode (bit 92 = 1) The Multipath interrupt can also be switched on/off by bit 4. Table 33. Multipath Interrupt (MPINT) MPINT (Pin 21) Bit 4 Off 0 On (MPINT active) 1 19 4838A–AUDR–10/04 AM Noise Blanker The AM Noise Blanker of the ATR4258 can be activated by bit 5. The noise peak is detected in the field strength of the first IF and if the disturbance exceeds the level defined by the bits 85 to 87, the signal is muted at the second IF. Table 34. AM Noise Blanker Activation AM Noise Blanker Bit 5 Off 0 On 1 Table 35. Sensitivity of AM Noise Blanker AM Noise Blanker Sensitivity 3-wire Bus Description Bit 87 Bit 86 Bit 85 Low 0 0 0 ..... ... ... ... Normal 0 1 1 ... ... ... ... High 1 1 1 The register settings of the ATR4258 are programmed by a 3-wire bus protocol. The bus protocol consists of separate commands. A defined number of bits are transmitted sequentially during each command. One command is used to program all bits of one register. The different registers available (see Table 36 on page 22) are addressed by the length of the command (number of transmitted bits) and by three address bits that are unique for each register of a given length. 8-bit registers are programmed by 8-bit commands and 24-bit registers are programmed by 24-bit commands. Each bus command starts with a rising edge on the enable line (EN) and ends with a falling edge on EN. EN has to be kept HIGH during the bus command. The sequence of transmitted bits during one command starts with the LSB of the first byte and ends with the MSB of the last byte of the register addressed. The DATA is evaluated at the rising edges of CLK. The number of LOW to HIGH transitions on CLK during the HIGH period of EN is used to determine the length of the command. The bus protocol and the register addressing of the ATR4258 are compatible to the addressing used in the U4256BM. That means both the ATR4258 and U4256BM can be operated on the same 3-wire bus as shown in the application circuit (Figure 20 on page 36). 20 ATR4258 4838A–AUDR–10/04 ATR4258 Figure 10. Pulse Diagram 8-bit command EN DATA LSB BYTE 1 MSB BYTE 1 MSB LSB CLK 24-bit command EN DATA LSB BYTE 2 MSB LSB BYTE 3 MSB CLK Figure 11. Bus Timing tR tF Enable tHEN tS tR tF Data tHDA tS tF tR Clock tH tL 21 4838A–AUDR–10/04 Data Transfer Table 36. Control Registers A24_100 MSB BYTE 3 Demodulator AM/FM/WB ADDR. 1 0 LSB Gain FM IF amplifier MSB BYTE 2 LSB AM OSC divider/multipath sensitivity Search Width of window MSB BYTE 1 BW/ Field MPX/ strength LPF/ LSB Time window stop signal 0 B93 B92 B91 B90 B89 B88 B87 B86 B85 B84 B83 B82 B81 B80 B79 B78 B77 B76 B75 B74 B73 A24_101 MSB BYTE 3 LSB MSB BYTE 2 LSB MSB BYTE 1 LSB st 1 IF1 Mixer Soft AGC + WBStart soft mute Tkampl. mute threshold Demod-gain threshhold FM IF AM/ AGC AM/FM depth AM/ FM FM ADDR. 1 0 BW 2nd mixer Int. IF2 reference shift Gain IFOUT IF2IN Dem. local pin 20 pin 28 Contr. OSC 1 B72 B71 B70 B69 B68 B67 B66 B65 B64 B63 B62 B61 B60 B59 B58 B57 B56 LSB MSB B55 B54 B53 B52 A24_111 MSB BYTE 3 AGC Local OSC ADDR. 1 1 1 0 B30 LSB MSB BYTE 2 Do not change (test mode bits) 0 0 0 0 0 B29 B28 B27 B26 B25 0 B24 0 Offset field strength (Pin 9) BYTE 1 Band-path filter LSB Fieldst. (pin 9) Local OSC prescaler (VCO buffer) B13 B12 B11 B10 0 B23 B22 B21 B20 B19 B18 B17 B16 B15 B14 A8_100 MSB BYTE 1 ADDR. 1 0 LSB Reset NoiseTest Mute MP/ MP blanker mode (pin 11) ADJ 0 0 B9 B8 B7 B6 B5 A8_101 MSB BYTE 1 MP INT ADDR. 1 0 1 B4 22 LSB Band-path filter Band width B3 B2 B1 B0 ATR4258 4838A–AUDR–10/04 ATR4258 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. All voltages are referred to GND (pin 25) Parameters Symbol Value Unit Supply voltage, pin 42 VS 10 V Power dissipation Ptot 1000 mW Tj 150 °C Ambient temperature range Tamb -40 to +85 °C Storage temperature range Tstg -50 to +150 °C Symbol Value Unit RthJA 60 K/W Junction temperature Thermal Resistance Parameters Junction ambient, soldered to PCB Operating Range All voltages are referred to GND (pin 25) Parameters Symbol Min. Typ. Max. Unit VS 8.0 8.5 10 V Tamb -40 +85 °C Supply voltage range, pin 42 Ambient temperature Electrical Characteristics Test conditions (unless otherwise specified): VS = 8.5 V, Tamb = 25°C No. Parameters Test Conditions Pin Symbol Min. Typ. Max. Unit Type* 42 VS 8.0 8.5 10 V C 1 Power Supply 1.1 Supply voltage 1.2 Supply current Standby mode (bit 92 = 0, bit 93 = 0) 42 IStby 35 45 mA A 1.3 Supply current Other operation modes 42 IS 50 65 mA A 260 MHz D 4.0 V A 2 VCO (Bit 52 = 0, Bit 30 = 1) 2.1 Frequency range 2.2 DC bias voltage 2.3 Buffer output voltage 16 250 mVrms C 2.4 Buffer output resistance 16 70 Ω D 2.5 Buffer output DC voltage 16 3.8 V A 3 fVCO 13 fosc = 120 MHz 70 3.4 3.7 4.1 4.4 FM RF-AGC 3.1 Saturation voltage No input signal 5 8.3 V A 3.2 Saturation voltage No input signal 5 VS - 0.2 V B *) Type means: A =100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter 23 4838A–AUDR–10/04 Electrical Characteristics (Continued) Test conditions (unless otherwise specified): VS = 8.5 V, Tamb = 25°C No. Parameters Test Conditions Pin 3.3 Threshold level In-band signal 30 3.4 Maximum threshold level Out-of-band signal (110 MHz), bit 64, 65 = 0 1 4 Symbol Min. Typ. Max. 115 100 103 106 Unit Type* dBµV C dBµV B AM RF-AGC, AM Mode (Bit 92 = 0, Bit 93 = 1) 4.1 Saturation voltage No input signal 7 8.3 V C 4.2 Saturation voltage No input signal 7 VS - 0.2 V C 4.3 Output voltage for minimum gain Bit 92 = 1 7 6.5 V C 4.4 Output voltage for minimum gain Bit 92 = 1 7 V C 4.5 Maximum control voltage No signal 6 V A 4.6 Maximum control voltage No signal 6 VS - 1.5 V B 4.7 Minimum control voltage AGC active 6 0.2 0.8 V A 4.8 Maximum threshold level Bits 64, 65 = 1 41 97 99 102 dBµV A 43, 44 14 16 20 mA A 4.1 mS D 5 Sum of current in pins 43, 44 Supply current 5.2 Conversion conductance 5.3 3rd-order input intercept point Pin 3 AC-grounded 5.4 Noise figure (SSB) Generator resistance 2.5 kΩ (pin 41) 5.5 Input bias DC voltage 5.6 Input resistance 5.7 Input capacitance 5.8 Maximum output voltage 6 7.1 VS 1.7 6.5 7.0 7.5 AM Mixer, AM Mode (Bit 92 = 0, Bit 93 = 1) 5.1 5.9 6.8 3, 41, 43, 44 41 IP3AMmix 132 dBµV C 43, 44 NFAMmix 12 dB C V A kΩ D pF D 3, 41 Single-ended, pin 39 AC-grounded 2.45 3, 41 2.8 13 3, 41 Differential Output resistance 3.1 3 43, 44 12 Vpp D 43, 44 100 kΩ D 43, 44 12 mA A 7 mS D FM Mixer (FM Mode (Bit 92 = 1, Bit 93 = 0) 6.1 Supply current 6.2 Conversion conductance 6.3 3rd-order intercept point 6.4 Noise figure (DSB) Sum of current in pins 43, 44 1, 2, 43, 44 Generator resistance 200 Ω 15 20 1, 2 IP3FMmix 125 dBµV C 43, 44 NFFMmix 10 dB C *) Type means: A =100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter 24 ATR4258 4838A–AUDR–10/04 ATR4258 Electrical Characteristics (Continued) Test conditions (unless otherwise specified): VS = 8.5 V, Tamb = 25°C No. Parameters 6.5 Input resistance 6.6 Input capacitance Pin 2 AC-grounded 6.7 Maximum differential output voltage VS = 8.5 V 6.8 Output resistance 7 Test Conditions Pin Symbol Min. Typ. Max. Unit Type* 1, 2 1.6 kΩ D 1 5 pF D 43, 44 12 Vpp D 43, 44 100 kΩ D dB B st 1 IF FM Amplifier, FM Mode (Bit 92 = 1, Bit 93 = 0) 7.1 Minimum voltage gain Bits 89, 90, 91 = 0 7.2 Temperature coefficient of gain Bit 66 = 0 TKmin 0.039 dB/K D 7.3 Temperature coefficient of gain Bit 66 = 1 TKmax 0.044 dB/K D 7.4 Input resistance Pin 39 AC-grounded 38 Ω D 7.5 Input capacitance Pin 39 AC-grounded 38 pF D Ω D 16 dB D 26 dB D 17 dB D kΩ D pF D 7.6 8 Output resistance Maximum voltage gain 8.2 Gain control range 8.3 Noise figure 8.4 Input resistance 8.5 Input capacitance 9 19 270 21 330 23 400 5 30 270 330 400 1st IF AM Amplifier, AM Mode (Bit 92 = 0, Bit 93 = 1) 8.1 8.6 38, 30 330 Ω load at pin 30 30, 33 Generator resistance 2.5 kΩ NFIFAM 33 Pin 39 AC-grounded Output resistance 10 33 1 30 270 330 400 Ω D 2nd Mixer 9.1 FM supply current Bit 92 = 1, Bit 93 = 0 23, 24 10 12 16 mA A 9.2 AM/WB supply current Bit 92 = 0, Bit 93 = 1 23, 24 7 8 10 mA A 9.3 Conversion conductance 2 mS D 9.4 Noise figure (SSB) 9.5 3rd-order input intercept point 9.6 AM/WB output resistance Bit 92 = 0, Bit 93 = 1 23, 24 9.7 Maximum differential output voltage AM/WB VS = 8.5 V 9.8 Maximum differential output voltage FM 9.9 9.10 26, 23, 24 Generator resistance 330 Ω (pin 26) 23, 24 NFMix2 23 dB C 26 IP3Mix2 132 dBµV C 100 kΩ D 23, 24 12 Vpp D 23, 24 1 Vpp D Input resistance 26 270 400 Ω D LO input voltage 22 80 500 mVpp D 330 *) Type means: A =100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter 25 4838A–AUDR–10/04 Electrical Characteristics (Continued) Test conditions (unless otherwise specified): VS = 8.5 V, Tamb = 25°C No. Parameters 9.11 LO input resistance 22 LO input bias voltage 22 9.12 10 Test Conditions Symbol Min. Typ. Input resistance Pin 27 AC-grounded 10.2 Voltage gain AM/WB mode (Bit 93 = 1) Pin 28 1 mVrms 10.3 Gain control range AM/WB mode (Bit 93 = 1) 10.4 DC output voltage 10.5 AC output voltage Unmodulated signal, 82 dBµV at pin 1 (IF AGC active) Bit 93 = 1 10.6 Output impedance Small signal 1 2.8 3.0 28 3.2 3 28, 20 42 45 48 47 Unit Type* kΩ D V A kΩ D dB A dB D 20 3.4 3.7 4.0 V A 20 150 180 230 mVrms A 20 Ω D 70 FM Demodulator Integrated Band-filter, FM Mode (Bit 92 = 1, Bit 93 = 0), BW Setting 2 11.1 AC output voltage Deviation = ±75 kHz, fmod = 1 kHz 11 11.2 Stereo roll-off Deviation = ±75 kHz, fmod = 38 kHz (reference: 1 kHz) 11 11.3 Total harmonic distortion Deviation = ±75 kHz, fmod = 1 kHz 11 THDFM 0.4 11.4 Maximum signal-tonoise ratio Dev. = ±22.5 kHz, fmod = 1 kHz, 50 µs de-emphase, signal input at 450 kHz 11 (S/N)FM 65 12 Max. 2nd IF Amplifier (Bit 55 = 0) 10.1 11 Pin 420 480 nd IF Filter = 120 kHz 540 mVrms B dB D % A dB C -2.0 0.7 Soft Mute, FM Mode (Bit 92 = 1, Bit 93 = 0, Bit 80 = 0) 12.1 Mute gain Bit 67 = 0, V (pin 34) = 2 V 11 -28 -26 -24 dB A 12.2 Mute gain Bit 67 = 1, V (pin 34) = 2 V 11 -24 -22 -20 dB A 135 150 170 mVrms A 2 % A dB C V A 13 AM Demodulator, AM Mode (Bit 92 = 0, Bit 93 = 1) 13.1 AC output voltage Modulation depth = 30%, fmod = 1 kHz 11 13.2 Total harmonic distortion Modulation depth = 80%, fmod = 1 kHz V(pin 35) = const. 11 THDAM 0.6 13.3 Maximum signal-to-noise ratio Modulation depth = 30%, fmod = 1 kHz 74 dBµV at pin 41 11 (S/N)AM 54 Bit 7 = 1 11 14 14.1 MPX Output DC output voltage 2.1 2.3 2.5 *) Type means: A =100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter 26 ATR4258 4838A–AUDR–10/04 ATR4258 Electrical Characteristics (Continued) Test conditions (unless otherwise specified): VS = 8.5 V, Tamb = 25°C No. Parameters Test Conditions Pin 14.2 Mute gain Bit 7 = 1, FM dev. = ±75 kHz, fmod = 1 kHz 14.3 Output resistance Small signal 15 Symbol Min. Typ. Max. Unit Type* 11 -65 -50 dB A 11 60 Ω D V A kΩ D V A 1 kΩ D 0.2 V C V C Search Stop Detector, INT Output 15.1 LOW saturation voltage 21 0 15.2 LOW output resistance 21 0.3 15.3 HIGH saturation voltage 21 15.4 HIGH output resistance 16 4.8 21 5.25 Deviation Sensor, FM Mode (Bit 92 = 1, Bit 93 = 0) 16.1 Offset voltage FM dev. = ±0 kHz FM demodulator adjusted 31 16.2 Output voltage FM dev. = ±75 kHz, fmod = 1 kHz 31 17 4.5 0.5 1.7 2.0 2.5 Field Strength Sensor, FM Mode (Bit 92 = 1, Bit 93 = 0, Bit 89 to 91 = 0, Bit 80 = 0, Bit 18 to 21 = 0) 17.1 Output voltage 60 dBµV at pin 33 9 0.8 1.3 1.8 V A 17.2 Output voltage Unmodulated signal 100 dBµV at pin 33 9 2.8 3.4 3.9 V A Field Strength Sensor, AM Mode (Bit 92 = 0, Bit 93 = 1, Bit 80 = 1, Bit 18 to 21 = 0) 17.3 Output voltage LOW field strength 60 dBµV at pin 28 9 1.5 1.8 2.1 V A 17.4 Output voltage HIGH field strength 94 dBµV at pin 28 9 3.0 3.3 3.6 V A 0 200 mV A 1.9 2.4 V A 18 18.1 18.2 Multipath Sensor, FM Mode (Bit 92 = 1, Bit 93 = 0) Offset voltage Unmodulated signal, 60 dBµV at pin 1 40 Output voltage AM modulation depth = 60%, fmod = 20 kHz, 60 dBµV at pin 1 40 1.5 *) Type means: A =100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter 27 4838A–AUDR–10/04 Electrical Characteristics (Continued) Test conditions (unless otherwise specified): VS = 8.5 V, Tamb = 25°C No. Parameters 19 Adjacent Channel Sensor, FM Mode (Bit 92 = 1, Bit 93 = 0), Bit 4 = 0 (Default BW Setting) 19.1 Pin Offset voltage Unmodulated signal 10 Output voltage AM mod. 10% fmod = 100 kHz AM mod. 60% fmod = 100 kHz 10 19.2 19.3 20 Test Conditions Symbol Min. Typ. Max. 200 1.2 0.3 0.6 1.9 2.5 Unit Type* mV C V A V D V D 3-wire Bus 20.1 Input voltage LOW 17, 18, 19 20.2 Input voltage HIGH 17, 18, 19 20.3 Leakage current 20.4 Clock frequency 20.5 Period of CLK HIGH LOW tH tL 20.6 Rise time EN, DATA, CLK tr 20.7 Fall time EN, DATA, CLK tf 20.8 Set-up time ts V = 0 V, 5 V 0.8 2.7 17, 18, 19 10 µA D 18 1.0 MHz D ns ns D 400 ns D 100 ns D 100 ns D 250 250 20.9 Hold time EN tHEN 250 ns D 20.10 Hold time DATA tHDA 0 ns D V A 21 Internally Generated Reference Voltages 21.1 Output voltage 12 5.5 5.7 6.0 21.2 Output voltage 29 3.0 V D 21.3 Output voltage 27 3.0 V D 21.4 Output voltage 39 3.0 V D *) Type means: A =100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter 28 ATR4258 4838A–AUDR–10/04 ATR4258 Application Information AM Prescaler (Divider) Settings The AM mixer is used for up conversion of the AM reception frequency to the IF frequency. Therefore an AM prescaler is implemented to generate the necessary LO from the VCO frequency. For the reception of the AM band different prescaler (divider) settings are possible. Table 37 gives an example for the AM prescaler (divider) settings and the reception frequencies. e.g., fVCO = 98.2 MHz ... 124 MHz fIF = 10.7 MHz f VCO f rec = ⎛ ------------------------------------⎞ – fIF ⎝ AM Prescaler⎠ Table 37. AM Prescaler (Divider) Settings and Reception Frequencies Divider (AM Prescaler) Note: Minimum Reception Frequency Maximum Reception Frequency [MHz] [MHz] divide by 2 38.4 51.3 divide by 3 20.033 30.633 divide by 4 13.85 20.3 divide by 5 8.94 14.1 divide by 6 5.667 9.967 divide by 7 3.329 7.014 divide by 8 1.575 4.8 divide by 9 0.211 3.078 divide by 10 0 1.7 Prescaler VCO Divider = 1 in this example. 29 4838A–AUDR–10/04 Local Oscillator and AM Prescaler Settings Table 38 gives an example for the VCO prescaler divider and AM prescaler divider settings and the reception frequencies. e.g., fVCO = 195.9 MHz ... 237.9 MHz fIF = +10.7 MHz or -10.7 MHz fVCO = (frec + fIF) × VCO Prescaler × AM Prescaler Table 38. VCO and AM Prescaler (Divider) Settings and Reception Frequencies Band Prescaler VCO IF [MHz] FM 2 +10.7 87.5 WB 1.5 -10.7 162.4 Minimum VCO Frequency Maximum VCO Frequency AM Prescaler 108 196.4 237.4 - 162.55 227.55 227.775 - Minimum Reception Maximum Reception Frequency [MHz] Frequency [MHz] JPN 3 -10.7 76 90 195.9 237.9 - LW/MW 2 +10.7 0.15 1.605 195.3 221.49 9 16m 1 +10.7 17.5 17.9 225.6 228.8 8 120m 2 +10.7 2.3 2.5 208 211.2 8 U4256 N- and R-divider Calculation AM Mode fVCO N = --------------------------------------------------------------------------------------------VCO-divider × AM Prescaler × f step fVCO f rec = ⎛⎝ ----------------------------------------------------------------------------⎞⎠ – f IF VCO-divider × AM Prescaler FM/WB Mode f VCO N = ------------------------------------------------VCO-divider × f step fVCO f rec = ⎛⎝ --------------------------------⎞⎠ – f IF VCO-divider All Modes f ref R = --------f step fref = reference oscillator frequency (e.g. 10.25 MHz) fVCO = VCO frequency frec = reception frequency fstep = step frequency (of the PLL) 30 ATR4258 4838A–AUDR–10/04 ATR4258 Diagrams The following data was measured with the application board (see Figure 20). In the measurement setup, a 50 Ω generator is terminated by 50 Ω and connected to the antenna input by a 50 Ω series resistor to achieve 75 Ω termination at the antenna input. The generator level specified is the output voltage of this 50 Ω generator at 50 Ω load. If the application board is replaced by a 75 Ω resistor, the voltage at this resistor is 6 dB below the specified voltage level of the 50 Ω generator. 1.0 1 0.9 0.9 0.8 0.8 0.7 0.7 +85°C 0.6 0.6 0.5 -40°C MPX 0.4 0.5 0.4 THD 0.3 THD [%] MPX Output Voltage [Vrms] Figure 12. FM Demodulator 0.3 -40°C 0.2 0.2 +85°C 0.1 0.1 0.0 0 10 20 30 40 50 60 70 80 90 0 100 Frequency Deviation [kHz] Note: Integrated band-filter BW setting: 120 kHz (bits 0 to 2 = 0, bit 3 = 1); 1 kHz modulation frequency; 50 µs de-emphasis (THD) Figure 13. Multipath Sensor Sensor Output Voltage 5 4 +85°C 3 -40°C 2 1 0 0 10 20 30 40 50 60 70 80 90 100 AM Modulation Depth [%] Note: AM modulation frequency 20 kHz; generator level 40 dBµV 31 4838A–AUDR–10/04 Figure 14. Multipath Sensor Frequency Response Sensor Output Voltage [V] 5.0 4.5 4.0 90% at 25°C 3.5 90% at -40°C 3.0 2.5 60% at 85°C 60% at 25°C 2.0 60% at -40°C 1.5 1.0 0.5 0.0 100 1000 10000 100000 AM Modulation Frequency [Hz] Note: Generator level 40 dBµV Deviation Sensor Output Voltage [V] Figure 15. Deviation Sensor 5 4 +85°C 3 2 -40°C 1 0 10000 30000 50000 70000 90000 Frequency Deviation [Hz] Note: FM modulation frequency: 1 kHz; BW setting 2nd IF filter = 120 kHz; demodulator fine tuning (bit 53 = 0) The center frequency of the integrated band filter has to adjusted (e.g., IF center frequency = 462.50 kHz). 32 ATR4258 4838A–AUDR–10/04 ATR4258 Figure 16. Deviation Sensor Frequency Response Sensor Output Voltage (V) 1.0 0.8 0.6 0.4 0.2 0.0 100 1000 10000 100000 FM Modulation Frequency (Hz) Note: FM frequency deviation: 22.5 kHz 10 5 4.5 0 4 MPX Output [dB] -10 3.5 -20 3 -30 2.5 -40 2 -50 1.5 -60 1 -70 0.5 -10 0 10 20 30 40 50 60 70 80 90 100 Fieldstrength Sensor Output Voltage [V] Figure 17. FM Input Level Sweep 110 120 Input Level [dBµV] Note: Soft mute threshold bits 68, 69 = 0, bit 70 = 1; soft mute gain bit 67 = 0 gain FM IF amplifier bit 89 to 91 = 1 33 4838A–AUDR–10/04 20 4.5 Pdes/Pundes Pdes/Pundes [dB] 10 4 0 3.5 -10 3 -20 2.5 -30 2 -40 1.5 -50 1 Adjacent -60 -70 -300 -250 -200 -150 -100 -50 0 0.5 50 100 150 200 250 0 300 Frequency Offset [kHz] Note: 34 Adjacent Channel Output Voltage [V] Figure 18. Selectivity Integrated bandfilter BW setting: 120 kHz Desired signal level adjusted to 40 dB S/N without undesired signal Undesired signal level adjusted to 26 dB S/N ATR4258 4838A–AUDR–10/04 ATR4258 Figure 19. Test Circuit Test Point 50 1 44 2 43 3 42 4 41 5 40 6 39 7 38 8 37 9 36 10 35 10n VS 50 10n VS 50 50 10n 100n 10n 47n 50 50 47n P29 10n 100n 10n 10n 11 12 1µ 50 ATR4258 100n 10n 34 200k P29 33 100n 13 32 14 31 15 30 16 29 17 28 18 27 19 26 10n P31 50 47n 50 50 10n 10n P29 V 22n 330 47n 1k3 Bus 47n Quarzoscillator 10.25 MHz 100n 10n 10k 20 25 21 24 22 23 50 50 VS 10n 50 50 35 4838A–AUDR–10/04 36 Ant FM 75 Ω R307 47 T111 J109 T302 BC848 D302 S391D 4µ7 L301 220n S391D D301 10n C315 C302 R306 470k 220n 100n C311 BC 858C 2k2 T102 BC858 C316 R105 100 100µH R308 T301 L303 2m2 2k2 R311 C319 6p8 L302 R103 1k 10n C117 R115 1k 2µ2 C106 L102 R112 47k R104 470 68k F102 R102 390 R313 1µ C111 C306 12p C112 10µ 3p9 C102 T101 BFR93A 10p F201 2 43 C56 D101 S391D 10n D103 C103 F101 C104 10n 18p BB804 27p 6p8 C107 1n C108 C109 1 44 100p C in F201 BB804 D102 R41 1k2 C113 100n 10n C209 R29 10 C201 C110 4n7 3 42 4 41 68k R122 68k R121 C11 10n 10n C307 100n 5 40 100n C308 6 39 R34 27 7 38 9 34 12 33 100n 14 15 30 C152 330p 1n C134 R131 5k6 BB804 1 20 22p F131 47p C131 C132 13 31 220n C207 220n C208 32 D131 R151 8k2 470p C77 6p8 C133 220n C114 11 100n 10 C116 22µ C203 10µ 10n ATR4258 35 C205 X301 C206 1k5 R305 R33 2k C115 8 470n 37 36 1µ C204 R111 200k C202 KR201 R304 5k6 3 18 17 28 4 17 18 27 C27 2µ2 C309 DAC3 5 10n 6 8 9 12 Q151 13 10 11 10n C157 SWO1 SWO3 SWO2 SWO4 7 14 10p 10.25 MHz C154 10n 10p 22 23 C312 C153 1n F302 R32 1k R106 10 100n 21 24 C310 R303 1k C155 15 10n C156 20 25 220n U4256BM 16 19 26 C159 KF302 Application Board Schematic C158 10n 10n C151 2 19 16 29 KR202 R152 10 10 R407 METER ADJAC MPX GND EN CLK DATA IF2OUT INT DEV MULTIP VS (+8.5 V to 10.5 V) Figure 20. Application Circuit ATR4258 4838A–AUDR–10/04 ATR4258 Ordering Information Extended Type Number Package Remarks ATR4258-ILSH SSO44 Tube, lead-free ATR4258-ILQH SSO44 Taped and reeled, lead-free Package Information 9.15 8.65 Package SSO44 Dimensions in mm 18.05 17.80 7.50 7.30 2.35 0.3 0.25 0.10 0.8 16.8 44 0.25 10.50 10.20 23 technical drawings according to DIN specifications 1 22 37 4838A–AUDR–10/04 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 ASIC/ASSP/Smart Cards 1150 East Cheyenne Mtn. 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