ATMEL ATR4255P Fm double-conversion system Datasheet

Features
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•
•
•
•
•
•
•
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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 for AM and FM
Automatic Alignment Possible
Lead-free Package
AM/FM
Receiver IC
ATR4255P
Electrostatic sensitive device.
Observe precautions for handling.
1. Description
The ATR4255P 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
ATR4256, an automatically aligned high-performance AM/FM tuner can be built.
These ICs are designed for highly sophisticated car radio applications.
Rev. 4883B–AUDR–01/06
Figure 1-1.
Block Diagram
MX1OA
IF1FMI
MX2OB
IF1AMI
V3
IF2IN
MX1OB
IF1REF
IF1OUT MX2IN
MX2OA
AMPLPF
8
7
AMAGC
6
AMVREG
43 44
38
39
33
30 29
26
23
24
28
V3P
IF2OUT
27
20
AM
AGC
FM
AM
dem.
MX1AMA
MX1AMB
41
32
3
V3
AGC
36
GNDMX
MX1FMB
MX1FMA
OSCOUT
OPLPF
AM
35
4
2
FM
Automatic
adjustment
AGC
1
16
37
IFAGCL
IFAGCH
FILADJ
Multipath
Divider
11
GNDOSC
OSCE
OSCB
Adjacent
channel
15
14
Stop
Soft
mute
MPX
OSC
13
V3
Band gap
Bus
17 18 19
5
12 25 42
Dev.
analog
INT
9
EN
DATA FMAGC
METER
GND
CLK
V57
VS
2
FM
dem.
22
MX2LO
10
ADJAC
21
INT
40
MULTIP
34
31
SMUTE
DEV
ATR4255P
4883B–AUDR–01/06
ATR4255P
2. Pin Configuration
Figure 2-1.
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
21
24
MX2OA
MX2LO 22
23
MX2OB
INT
3
4883B–AUDR–01/06
Table 2-1.
4
Pin Description
Pin
Symbol
Function
1
2
3
4
5
MX1FMA
MX1FMB
MX1AMB
GNDMX
FMAGC
1st mixer FM input A
1st mixer FM input B
1st mixer AM input B
Ground 1st mixer, preamplifier AGC
FM preamplifier AGC
6
7
8
9
10
AMVREG
AMAGC
AMPLPF
METER
ADJAC
AM control voltage
AM preamplifier AGC
AM AGC LP filter
Field strength output
Adjacent channel detection output
11
12
13
14
MPX
V57
OSCB
OSCE
15
16
GNDOSC
OSCOUT
Oscillator ground
Oscillator output
17
18
EN
CLK
3-wire bus enable
3-wire bus clock
19
20
DATA
IF2OUT
3-wire bus data
2nd IF amplifier output
21
22
INT
MX2LO
Interrupt, stop signal
10.25 MHz input for 2nd mixer
23
24
25
MX2OB
MX2OA
GND
2nd mixer output B
2nd mixer output A
Ground
26
27
28
29
30
31
32
33
34
35
MX2IN
V3P
IF2IN
V3
IF1OUT
DEV
OPLPF
IF1AMI
SMUTE
IFAGCH
2nd mixer input
3V reference for AMPIN, AMIFAGC, Control, IF2IN
2nd IF amplifier input
3V reference for IF1OUT, MX2IN
1st IF amplifier output
Deviation detect output, test output
Operating point LPF
1st IF AM amplifier input
Soft mute control input
IF AGC LP filter high time
36
37
38
IFAGCL
FILADJ
IF1FMI
IF AGC LP filter low time constant
Filter adjust
1st IF FM amplifier input
39
40
41
42
43
IF1REF
MULTIP
MX1AMA
VS
MX1OA
44
MX1OB
Multiplex signal
5.7V reference voltage
Oscillator basis
Oscillator emitter
1st IF and MX1OUT reference, MX1AMA, MX1AMB
Multipath detection output
1st mixer AM input A
Supply voltage
1st mixer output A
1st mixer output B
ATR4255P
4883B–AUDR–01/06
ATR4255P
3. Functional Description
The ATR4255P implements an AM up/down-conversion reception path from the RF input signal
to the AM-demodulated audio frequency output signal, and for FM 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 soft mute 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. See Section “3-wire Bus
Description” on page 19 for the bus protocol and the bit-to-register mapping. The meaning of the
control bits is described in the following sections.
3.1
Reception Mode
The IC can be operated in four different modes; modes AM, FM, Weather band (WB), and
Standby are selected by means of bits 92 and 93 as shown in Table 3-1.
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 pins 23 and 24 is increased and the input of the 2nd IF
amplifier can be switched between pins 23, 24 and 28. The output of the 2nd IF amplifier is fed to
the integrated bandfilter and FM demodulator. The output of the FM demodulator is available at
MPX output, pin 11.
WB mode is similar to FM mode, but the input of the 2nd IF amplifier is fixed to pin 28, the range
of the bandwidth control of the integrated band filter 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.
Table 3-1.
Operating Mode
AM/FM/Weather Channel
Bit 93
Bit 92
Standby
0
0
FM
0
1
AM
1
0
Weather band (WB)
1
1
5
4883B–AUDR–01/06
3.2
Test Mode
A special test mode is implemented for final production test only. This mode is activated by setting bit 9 to “1”. This mode is not intended to be used in customer applications. For normal
operation, bit 9 has to be set to “0”. Bits 18 to 30 are deactivated in normal operation mode.
Table 3-2.
3.3
Test Mode
Mode
Bit 9
Normal operation
0
Test mode
1
VCO
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 ATR4256. The VCO signal is provided at the
buffered output pin 16 to be fed to the PLL circuit.
3.4
FM RF-AGC
The FM RF-AGC circuit includes a wideband 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 3-1) 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 bits 64 and 65 as
shown in Table 3-3. The in-band AGC threshold referred to the FM mixer input (pin 1, pin 2)
depends on the gain of the FM IF amplifier and can be adjusted using bits 89 to 91.
Figure 3-1.
FM RF-AGC Bit 92
VS
Pin 42
C111
R115
Pin 5
PIN Diode
AGC
6
B92
ATR4255P
4883B–AUDR–01/06
ATR4255P
Table 3-3.
3.5
FM-AGC Threshold
FM-AGC Threshold
Bit 65
Bit 64
104 dBµV
0
0
101 dBµV
0
1
98 dBµV
1
0
92 dBµV
1
1
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 inputs
(pin 3, pin 41). This threshold level can be set by bits 62 and 63 (Table 3-4). 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 3-4.
3.6
AM-AGC Threshold
AM-AGC Threshold
Bit 63
Bit 62
99 dBµV
0
0
102 dBµV
0
1
104 dBµV
1
0
105 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.
3.7
AM 1st Mixer
The AM 1st mixer is used for up-conversion of the AM reception frequency to the 1 st 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 as shown in
Table 3-5.
Table 3-5.
Divide Factor of the AM Prescaler
Divider AM Prescaler
Bit 93
Bit 92
Bit 84
Bit 83
Bit 82
Bit 81
Divide by 10
1
0
x
0
0
0
Divide by 6
1
0
x
0
0
1
Divide by 7
1
0
x
0
1
0
Divide by 8
1
0
x
1
0
0
Divide by 4
1
0
x
1
0
1
7
4883B–AUDR–01/06
3.8
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
bits 89 to 91 (Table 3-6). The input and the output resistance is 330Ω, and fits to external
ceramic filters.
Two different temperature coefficients (TC) of the FM IF amplifier can be selected by setting
bit 66 (Table 3-7).
Table 3-6.
Table 3-7.
3.9
Gain of the FM IF Amplifier
Gain FM IF
Bit 91
Bit 90
Bit 89
20 dB
0
0
0
22 dB
0
0
1
24 dB
0
1
0
26 dB
0
1
1
28 dB
1
0
0
29 dB
1
0
1
30 dB
1
1
0
31 dB
1
1
1
Temperature Coefficient Setting of FM IF Amplifier
Temperature Coefficient (TC) of the IF Amplifier
Bit 66
TKmin
0
TKmax
1
AM 1st IF Amplifier
In AM mode, the gain of the 1st IF amplifier is controlled by the IF-AGC to extend the control
range of the IF-AGC.
3.10
2nd Mixer
The 2nd mixer is used in AM, FM and WB mode. The mixer input has 330Ω 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 bits 60 and 61
(Table 3-8).
Table 3-8.
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 ATR4256.
8
ATR4255P
4883B–AUDR–01/06
ATR4255P
Table 3-9.
Bit 61
Bit 60
FM BW Mixer 2
0
0
150 kHz
0
1
200 kHz
1
0
250 kHz
1
Note:
3.11
FM Bandwidth (BW) Mixer 2
1
450 kHz
The bandwidth also depends on the values of the application circuit.
2nd IF Amplifier
In AM and WB mode, the input of the second IF amplifier is pin 28, which 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 and 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 3-10.
3.12
2nd IF Filter in FM Mode
2nd IF Filter
Bit 54
Internal filter
0
External and internal filter
1
IF-AGC
The IF-AGC controls the level of the 2nd IF signal that is passed to the AM demodulator input or
the integrated FM bandfilter, and to the 2nd IF output (pin 20).
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 mode and in
AM search mode. The long time constant (IFAGCH) is used for AM reception.
Table 3-11.
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.
9
4883B–AUDR–01/06
3.13
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 to “1”.
Table 3-12.
3.14
Pin 20 Output Setting
Pin 20
Bit 55
2nd IF output
0
Multipath field strength
1
Automatic IF Center Frequency Adjustment
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 3-2.
Automatic IF Center Frequency Adjustment
Pin 22
10.25 MHz
Automatic
frequency
adjustment
+
Bit 56 to 59
Pin 37
Center
freq.
FM demod.
Center
freq.
FM
band filter
Bit 14 to 17
+
Center
freq.
Adj. channel
sensor
Bits 5 and 6
For fine tuning, the center frequency of all these integrated active filters (band filter, demodulator, and adjacent channel sensor) can be shifted in steps of 6.25 kHz using bits 56 to 59 (Table
3-13 on page 11). Additionally, the center frequency of the band filter can be adjusted separately
by means of bits 14 to 17, if bit 4 is set to “1”. If bit 4 is set to “0”, the default setting is used.
10
ATR4255P
4883B–AUDR–01/06
ATR4255P
1
Table 3-13.
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
461.50 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 3-14.
FM Band Filter Center Frequency Correction
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
11
4883B–AUDR–01/06
3.15
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 using
bits 0 to 3 (Table 3-15) 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 using bits 14 to 17 (bit 4
set to “1”). The field strength after the integrated FM band filter that is available at pin 20
(bit 55 set to “1”) can be used for this purpose.
Table 3-15.
3.16
Bandwidth of the Integrated FM Band Filter
IF Bandwidth
Bit 3
Bit 2
Bit 1
Bit 0
200 kHz
0
0
0
0
190 kHz
0
0
0
1
180 kHz
0
0
1
0
170 kHz
0
0
1
1
160 kHz
0
1
0
0
150 kHz
0
1
0
1
140 kHz
0
1
1
0
130 kHz
0
1
1
1
120 kHz
1
0
0
0
110 kHz
1
0
0
1
100 kHz
1
0
1
0
90 kHz
1
0
1
1
80 kHz
1
1
0
0
70 kHz
1
1
0
1
60 kHz
1
1
1
0
50 kHz
1
1
1
1
FM Demodulator
For weather band reception, the gain of the FM demodulator is increased and can be adjusted
by means of bits 71 and 72 (Table 3-16 on page 13) 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”.
12
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4883B–AUDR–01/06
ATR4255P
Figure 3-3.
FM Demodulator Automatic Fine Tuning
FM demod.
Center freq.
MPX
AM
AGC
B92
+
IFAGCH
V3
(10 nF)
Bit 53
Automatic
frequency
adjustment
The center frequency of the FM demodulator can be adjusted by means of bits 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 3-16.
Demodulator Gain in Weather Band Mode Relative to FM Mode
Bit 72
Bit 71
12 dB
0
0
15 dB
0
1
18 dB
1
0
21 dB
1
1
Table 3-17.
3.17
Demodulator Gain in Weather Band Mode
Demodulator Fine Adjustment
Demodulator Fine Adjustment
Bit 53
Fine tuning ON
0
Fine tuning OFF
1
Soft Mute
The soft mute functionality is implemented to reduce the output level of the FM demodulator at
low input signal levels, and to limit the noise at MPX output at low input signal levels. 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 bits 68 to 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 pins 34 and 29.
The field strength signal available at pin 9 is used for soft mute. Therefore, the soft mute threshold referred to the input of the FM mixer depends on the gain from FM mixer input to the field
strength sensor.
13
4883B–AUDR–01/06
Table 3-18.
Soft Mute Threshold
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
Table 3-19.
–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
Maximum Soft Mute
Maximum Value of Soft Mute
Bit 67
28 dB
0
24 dB
1
Figure 3-4.
Soft Mute
+
FS (Pin 9)
Bit 67
Pin 34
Gain FM demodulator
Bits 68 to 70
Pin 29
3.18
V3
MPX Output
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” (Table 3-20).
The bandwidth of the low-pass filter at the MPX output can be set to 90 kHz or 180 kHz using
bit 79 (Table 3-21 on page 15).
Table 3-20.
14
MPX Output Mute
MPX Output
Bit 7
MPX out, pin 11 normal operation
0
Mute ON
1
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4883B–AUDR–01/06
ATR4255P
Table 3-21.
3.19
MPX Output Bandwidth
Bandwidth MPX Low-pass Filter
Bit 79
90 kHz
0
180 kHz
1
Receiving Condition Analyzer
ATR4255P implements several sensors that provide information about the receiving condition of
the selected station.
3.20
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 when 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 mode and the AGC field strength is used in AM mode.
Table 3-22.
3.21
Field Strength Selection
Field Strength Narrow Band/Wide Band
Bit 80
Field strength at pin 26 (wide band)
0
Field strength from IF-AGC (narrow band)
1
Search Stop Detector
A search stop detector is available in AM and FM/WB mode. A STOP condition is signaled if the
frequency of the ZF signal is within a window around the center frequency of 450 kHz. The width
of this search stop window can be set in the range of 0.5 kHz to 80 kHz using bits 85 to 87. The
frequency of the ZF signal is measured by counting the number of periods of the ZF signal during a measurement time which is determined by the value of bits 73 to 78. The inverted STOP
signal is available at pin 21 as shown in Table 3-25 on page 16. The frequency of 10.25 MHz at
pin 22 is used as time reference.
Table 3-23.
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
...
...
...
...
...
...
...
63 × 3.1969 ms
1
1
1
1
1
1
15
4883B–AUDR–01/06
Table 3-24.
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 3-25.
Signals Available at Digital Output Pin 21
Bit 88
3.22
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)
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 3-5).
The output voltage at pin 31 is proportional to the frequency deviation in FM/WB or the
modulation depth in AM.
Figure 3-5.
Deviation Sensor
+
MPX
4k
Pin 31
25k
3.23
Adjacent Channel Sensor
The adjacent channel sensor is active only in FM mode, and measures the field strength outside
the reception band. By setting the center frequency of the band filter of the adjacent channel
sensor below or above the 2nd IF frequency (bits 5 and 6), it can be determined whether the disturbance signal is located above or below the reception frequency (see Table 3-28 on page 18).
The bandwidth of the band filter used in the adjacent channel sensor can be changed by means
of bits 10 to 13. If bit 4 = 0, the default bandwidth setting is used. The output of the adjacent
channel sensor is independent of the bandwidth setting of the integrated FM band filter.
16
ATR4255P
4883B–AUDR–01/06
ATR4255P
Figure 3-6.
Adjacent Channel Sensor
IF
Intergrated FM band filter
+
log
+
4k
Pin 10
50k
log
Table 3-26.
Table 3-27.
Bandwidth (BW) of the Adjacent Channel Detector Filter
BW Adjustment
Bit 13
Bit 12
Bit 11
Bit 10
3 kHz
0
0
0
0
16 kHz
0
0
1
0
32 kHz
0
1
0
0
50 kHz
0
1
1
0
65 kHz
1
0
0
0
80 kHz
1
0
1
0
95 kHz
1
1
0
0
110 kHz
1
1
1
0
50 kHz
0
0
0
1
65 kHz
0
0
1
1
80 kHz (default)
0
1
0
1
95 kHz
0
1
1
1
110 kHz
1
0
0
1
130 kHz
1
0
1
1
145 kHz
1
1
0
1
160 kHz
1
1
1
1
Center Frequency Adjacent Channel Sensor
Center Frequency
Bit 6
Bit 5
450 kHz
0
0
300 kHz
0
1
700 kHz
1
0
Filter OFF
1
1
17
4883B–AUDR–01/06
Table 3-28.
3.24
Output Voltage of Adjacent Channel Sensor for Different Receiving Conditions
and Center Frequencies
Adjacent Channel Disturbance
300 kHz
450 kHz
600 kHz
No
High
Low
High
Below
High
High
Low
Above
Low
High
High
Multipath Sensor
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 3-7.
Multipath Sensor
+
Pin 40
4k
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 an adjustable threshold (adjustable by setting bits 81 to 84, Table 3-30
on page 19), the MPX signal may be muted and this situation (MPINT) can be signaled at pin 21
(INT) as shown in Table 3-25 on page 16. Muting of the MPX signal during multipath disturbances can be activated be setting bit 8 (Table 3-29).
Table 3-29.
18
Multipath Noise Canceller
Multipath Noise Canceller
Bit 8
Active
0
Not active
1
ATR4255P
4883B–AUDR–01/06
ATR4255P
Table 3-30.
3.25
Sensitivity of the MNC
Sensitivity MNC (Threshold)
Bit 93
Bit 92
Bit 84
Bit 83
Bit 82
Bit 81
Off
x
1
0
0
0
0
Low
x
1
0
0
0
1
...
x
1
0
0
1
0
(–18 dB)
x
1
0
0
1
1
...
x
1
0
1
0
0
...
x
1
0
1
0
1
...
x
1
0
1
1
0
Normal (–12 dB)
x
1
0
1
1
1
...
x
1
1
0
0
0
...
x
1
1
0
0
1
...
x
1
1
0
1
0
...
x
1
1
0
1
1
...
x
1
1
1
0
0
...
x
1
1
1
0
1
...
x
1
1
1
1
0
High (–9 dB)
x
1
1
1
1
1
3-wire Bus Description
The register settings of ATR4255P are programmed by a 3-wire bus protocol. The bus protocol
consists of separate commands. A defined number of bits is transmitted sequentially during
each command.
One command is used to program all bits of one register. The different registers available (see
Table 3-31 on page 21) 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 ATR4255P are compatible to the addressing
used in ATR4256. That means ATR4255P and ATR4256 can be operated on the same 3-wire
bus as shown in the application circuit.
19
4883B–AUDR–01/06
Figure 3-8.
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 3-9.
Bus Timing
tR
tF
Enable
tS
tHEN
tF
tR
Data
tHDA
tS
tR
tF
Clock
tH
tL
20
ATR4255P
4883B–AUDR–01/06
ATR4255P
3.26
Data Transfer
Table 3-31.
Control Registers
A24_100
MSB
BYTE 3
ADDR.
1
0
LSB
AM/FM/
WB
0
AM
FM
B93
B92
MSB
B91
B90
BYTE 2
LSB
MSB
BYTE 1
OSC divider/multipath
Field BWM
Search Width of window
sensitivity
strength PX
Gain FM
IF amplifier
B89
B88
LSB
MSB
B87 B86 B85 B84 B83 B82 B81
B80
B79
LSB
Time window stop signal
B78 B77 B76 B75 B74 B73
A24_101
MSB
BYTE 3
WBDemodGain
ADDR.
1
0
Soft
mute
Start soft mute
BYTE 2
Tk-FM
FM-AGC
IF
LSB MSB
AM-AGC
FM BW 2nd
mixer
BYTE 1
MP
FS
IF2 center frequency
LSB
FM
ext
Dem. Not
Adj. used
1
x
B72 B71 B70
B69
B68
B67
B66
B65 B64 B63 B62 B61 B60
B59
B58
B57 B56 B55 B54
B53
B52
A24_111
MSB
BYTE 3
LSB MSB
ADDR.
1
1
BYTE 2
LSB MSB
Center frequency of
bandfilter
Used in test mode only
1
B30
B29
B28
B27
B26
B25
B24
BYTE 1
x
x
B23
B22
B21
B20
B19
B18
1
0
B17
B16
0
0
LSB
Bandwidth adj. channel
sensor
0
B15 B14 B13
1
0
1
B12
B11
B10
A8_100
MSB
BYTE 1
ADDR.
1
0
LSB
Test MPoff Mute
0
Adj.
channel
sensor
0
B9
B8
B7
B6
B5
A8_101
MSB
BYTE 1
ADDR.
1
0
Optimize
LSB
Bandwidth
1
B4
B3
B2
B1
B0
21
4883B–AUDR–01/06
4. Absolute Maximum Ratings
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating
only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this
specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
All voltages refer 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
5. Thermal Resistance
Parameters
Junction ambient, soldered to PCB
6. Operating Range
All voltages are referred to GND (pin 25).
Parameters
Symbol
Supply voltage range, pin 42
Ambient temperature
Min.
Typ.
VS
7.5
8.5
Tamb
–40
Max.
Unit
10
V
+85
°C
7. Electrical Characteristics
Test conditions (unless otherwise specified): VS = 8.5V, Tamb = 25°C.
No.
Parameters
1
Power Supply
1.1
Supply voltage
Test Conditions
1.2
Supply current
Standby mode
(bit 92 = 0, bit 93 = 0)
1.3
Supply current
Other operation modes
2
Pin
Symbol
Min.
Typ.
Max.
Unit
Type*
7.5
8.5
10
V
C
42
VS
42
IStby
20
25
mA
A
42
IS
50
60
mA
A
160
MHz
D
VCO
2.1
Frequency range
fVCO
2.2
DC bias voltage
2.3
Buffer output voltage
2.4
Buffer output resistance
16
2.5
Buffer output DC
voltage
16
fosc = 120 MHz
70
13
2.8
3.0
3.2
V
A
16
130
150
250
mVrms
A
Ω
D
V
A
70
2.8
3.0
3.2
*) Type means: A =100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
22
ATR4255P
4883B–AUDR–01/06
ATR4255P
7. Electrical Characteristics (Continued)
Test conditions (unless otherwise specified): VS = 8.5V, Tamb = 25°C.
No.
Parameters
3
FM RF-AGC
Test Conditions
Pin
Symbol
Min.
Typ.
Max.
Unit
Type*
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
3.3
Threshold level
In-band signal
30
dBµV
D
3.4
Maximum threshold
level
Out-of-band signal
(110 MHz),
bit 64, 65 = 0
1
100
dBµV
A
4
110
102
104
AM RF-AGC, AM Mode (Bit 92 = 0, Bit 93 = 1)
4.1
Saturation voltage
No input signal
7
8.3
V
A
4.2
Saturation voltage
No input signal
7
VS – 0.2
V
B
4.3
Output voltage for
minimum gain
Bit 92 = 1
7
6.5
V
A
4.4
Output voltage for
minimum gain
Bit 92 = 1
7
V
B
4.5
Maximum control
voltage
V(pin 8) = 3V
6
V
A
4.6
Maximum control
voltage
V(pin 8) = 3V
6
VS – 1.5
V
B
4.7
Minimum control
voltage
V(pin 8) = 6V
6
0.2
0.7
V
A
4.8
Minimum threshold
level
Bits 62, 63 = 0
41
97
99
101
dBµV
A
43, 44
14
16
20
mA
A
4.1
mS
D
5
7.1
VS – 1.7
6.5
7.0
7.5
AM Mixer, AM Mode (Bit 92 = 0, Bit 93 = 1)
Sum of current in
pins 43 and 44
5.1
Supply current
5.2
Conversion
conductance
5.3
3rd-order input intercept
Pin 3 AC grounded
point
5.4
Noise figure (SSB)
5.5
Input bias DC voltage
5.6
Input resistance
5.7
Input capacitance
5.8
Maximum output
voltage
5.9
Output resistance
6
6.8
3, 41, 43,
44
Generator resistance
2.5 kΩ (pin 41)
41
IP3AMmix
132
dBµV
C
43, 44
NFAMmix
14
dB
C
V
A
kΩ
D
pF
D
3, 41
Single-ended, pin 39
AC grounded
2.4
3, 41
2.6
2.5
3, 41
Differential
2.9
3
43, 44
12
Vpp
D
43, 44
100
kΩ
D
43, 44
15
mA
A
mS
D
FM Mixer (FM Mode (Bit 92 = 1, Bit 93 = 0)
6.1
Supply current
6.2
Conversion
conductance
Sum of current in
pins 43 and 44
1, 2, 43,
44
17.5
20
7
*) Type means: A =100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
23
4883B–AUDR–01/06
7. Electrical Characteristics (Continued)
Test conditions (unless otherwise specified): VS = 8.5V, Tamb = 25°C.
No.
Parameters
Test Conditions
rd
6.3
3 -order intercept point
6.4
Noise figure (DSB)
6.5
Input resistance
6.6
Input capacitance
Pin 2 AC grounded
6.7
Maximum differential
output voltage
VS = 8.5V
6.8
Output resistance
7
Generator resistance
200Ω
Pin
Symbol
1, 2
IP3FMmix
43, 44
NFFMmix
Min.
Typ.
Max.
Unit
Type*
120
dBµV
C
10
dB
C
1, 2
1.6
kΩ
D
1
5
pF
D
43, 44
12
Vpp
D
43, 44
100
kΩ
D
dB
A
st
1 IF FM Amplifier, FM Mode (Bit 92 = 1, Bit 93 = 0)
7.1
Minimum voltage gain
7.2
Temperature coefficient
Bit 66 = 0
of gain
TKmin
0.039
dB/K
D
7.3
Temperature coefficient
Bit 66 = 1
of gain
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
7.6
Output resistance
Ω
D
16
dB
D
26
dB
D
20
dB
C
kΩ
D
pF
D
8
38, 30
19
270
21
330
23
400
5
30
270
330
400
st
1 IF AM Amplifier, AM Mode (Bit 92 = 0, Bit 93 = 1)
8.1
Maximum voltage gain
8.2
Gain control range
8.3
Noise figure
8.4
Input resistance
8.5
Input capacitance
8.6
Output resistance
9
Bits 89, 90, 91 = 0
nd
2
330Ω load at pin 30
30, 33
Generator resistance
2.5 kΩ
NFIFAM
33
Pin 39 AC grounded
10
33
1
30
270
330
400
Ω
D
Mixer
9.1
FM supply current
Bit 92 = 1, bit 93 = 0
23, 24
10
14
16
mA
A
9.2
AM/WB supply current
Bit 92 = 0, bit 93 = 1
23, 24
8
10
12
mA
D
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 = 8.5V
9.8
Maximum differential
output voltage FM
9.9
9.10
26, 23,
24
Generator resistance
330Ω (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
24
ATR4255P
4883B–AUDR–01/06
ATR4255P
7. Electrical Characteristics (Continued)
Test conditions (unless otherwise specified): VS = 8.5V, Tamb = 25°C.
No.
Parameters
9.11
LO input resistance
22
9.12
LO input bias voltage
22
10
Test Conditions
Pin
Symbol
Min.
Typ.
Max.
1
2.8
3.0
3.2
Unit
Type*
kΩ
D
V
A
kΩ
D
dB
A
2nd IF Amplifier (Bit 55 = 0)
10.1
Input resistance
Pin 27 AC grounded
10.2
Maximum voltage gain
AM/WB mode
(bit 93 = 1)
10.3
Gain control range
AM/WB mode
(bit 93 = 1)
44
dB
D
10.4
Maximum voltage gain
FM mode (bit 92 = 1, bit
23, 24 20
93 = 0, bit 54 = 0)
37
dB
D
10.5
DC output voltage
10.6
AC output voltage
10.7
Output impedance
11
28
3
28, 20
44
47
50
20
3.1
3.4
3.7
V
A
Unmodulated signal,
82 dBµV at pin 1
(IF AGC active)
20
145
175
200
mVrms
A
Small signal
20
Ω
D
70
FM Demodulator Integrated Bandfilter, FM Mode (Bit 92 = 1, Bit 93 = 0), BW Setting 2
nd
IF Filter = 120 kHz
11.1
AC output voltage
Deviation = ±75 kHz,
fmod = 1 kHz
11
420
480
540
mVrms
A
11.2
Stereo roll-off
Deviation = ±75 kHz,
fmod = 38 kHz
(reference: 1 kHz)
11
–2.3
–2.0
–1.7
dB
A
11.3
Total harmonic
distortion
Deviation = ±75 kHz,
fmod = 1 kHz
11
THDFM
0.4
0.7
%
A
11.4
Maximum
signal-to-noise ratio
(SNR)
Dev. = ±22.5 kHz,
fmod = 1 kHz, 50 µs deemphasize, signal input
at 450 kHz
11
(S/N)FM
dB
A
12
62
65
Soft Mute, FM Mode (Bit 92 = 1, Bit 93 = 0, Bit 80 = 0)
12.1
Mute gain
Bit 67 = 0,
V (pin 34) = 2V
11
–31
–28
–26
dB
A
12.2
Mute gain
Bit 67 = 1,
V (pin 34) = 2V
11
–26
–24
–22
dB
A
12.3
Soft mute threshold
Bits 89 to 91 = 0,
Bits 68 to 70 = 1
1
50
53
56
dBµV
B
350
400
450
mVrms
A
0.6
2
%
A
dB
A
13
AM Demodulator, AM Mode (Bit 92 = 0, Bit 93 = 1)
13.1
AC output voltage
Modulation depth =
80%, fmod = 1 kHz
11
13.2
Total harmonic
distortion
Modulation depth =
80%, fmod = 1 kHz,
V(pin 35) = const.
11
THDAM
13.3
Maximum
signal-to-noise ratio
(SNR)
Modulation depth =
80%, fmod = 1 kHz,
74 dBµV at pin 41
11
(S/N)AM
52
54
*) Type means: A =100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
25
4883B–AUDR–01/06
7. Electrical Characteristics (Continued)
Test conditions (unless otherwise specified): VS = 8.5V, Tamb = 25°C.
No.
Parameters
Test Conditions
Pin
14
MPX Output
DC output voltage
Bit 7 = 1
11
14.2
Mute gain
Bit 7 = 1,
FM dev. = ±75 kHz,
fmod = 1 kHz
14.3
Output resistance
Small signal
14.1
15
Symbol
Min.
Typ.
Max.
Unit
Type*
2.15
2.25
2.4
V
A
11
–70
–50
dB
A
11
60
Ω
D
V
A
kΩ
D
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
21
1
20
2.0
16
4.75
5.0
V
A
kΩ
D
150
mV
A
2.5
V
A
Deviation Sensor, FM Mode (Bit 92 = 1, Bit 93 = 0)
16.1
Offset voltage
FM dev. = ±0 kHz
31
16.2
Output voltage
FM dev. = ±75 kHz,
fmod = 1 kHz
31
17
4.5
0.5
1.7
Field Strength Sensor, FM Mode (Bit 92 = 1, Bit 93 = 0, Bits 89 to 91 = 0, Bit 80 = 0)
17.1
Offset voltage
No signal
9
0.4
0.75
1.1
V
A
17.2
Output voltage
Unmodulated signal
84 dBµV at pin 1
9
2.7
3.0
3.3
V
A
Field Strength Sensor, AM Mode (Bit 92 = 0, Bit 93 = 1, Bit 80 = 1)
17.3
Output voltage LOW
field strength
63 dBµV at pin 28
9
0.7
0.9
1.1
V
A
17.4
Output voltage HIGH
field strength
94 dBµV at pin 28
9
2.3
2.5
2.7
V
A
20
200
mV
A
1.8
2.2
V
A
18
18.1
18.2
19
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
1.4
Adjacent Channel Sensor, FM Mode (Bit 92 = 1, Bit 93 = 0), Bit 4 = 0 (Default BW Setting)
19.1
Offset voltage
Unmodulated signal
10
100
300
mV
A
19.2
Output voltage
FM dev. = ±50 kHz,
fmod = 1 kHz
10
0.6
1.0
V
A
Output voltage
Desired
FM dev. = ±75 kHz,
fmod = 1 kHz
Undesired:
unmodulated RF level
Undesired/desired:
+30 dB frequency offset
= –150 kHz
10
1.2
1.6
V
A
19.3
20
1.0
3-wire Bus
*) Type means: A =100% tested, B = 100% correlation tested, C = Characterized on samples, D = Design parameter
26
ATR4255P
4883B–AUDR–01/06
ATR4255P
7. Electrical Characteristics (Continued)
Test conditions (unless otherwise specified): VS = 8.5V, Tamb = 25°C.
No.
Parameters
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
20.9
Hold time EN
20.10
Hold time DATA
21
Test Conditions
V = 0V, 5V
Pin
Symbol
Min.
Typ.
Max.
Unit
Type*
0.8
V
D
V
D
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
tHEN
250
ns
D
tHDA
0
ns
D
V
A
250
250
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
27
4883B–AUDR–01/06
8. Diagrams
The following data was measured with the application board (Figure 8-9 on page 32).
In the measurement setup, a 50Ω generator is terminated by 50Ω and connected to the antenna
input by a 50Ω series resistor to achieve 75Ω termination at the antenna input. The generator
level specified is the output voltage of this 50Ω generator at 50Ω load. If the application board is
replaced by a 75Ω resistor, the voltage at this resistor is 6 dB below the specified voltage level of
the 50Ω generator.
FM Demodulator
1.0
1
0.9
0.9
0.8
0.8
+85˚C
0.7
0.7
0.6
0.6
-40˚C
0.5
0.5
MPX
0.4
0.4
THD
0.3
THD (%)
MPX Output Voltage (Vrms)
Figure 8-1.
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 bandfilter BW setting: 120 kHz, bits 0 to 2 = 0, bit 3 = 1;
1 kHz modulation frequency; 50 µs de-emphasis (THD).
Figure 8-2.
Multipath Sensor
5.0
Sensor Output Voltage (V)
4.5
4.0
3.5
3.0
+85˚C
-40˚C
2.5
2.0
+25˚C
1.5
1.0
0.5
0.0
0
20
40
60
80
100
AM Modulation Depth (%)
Note:
28
AM modulation frequency 20 kHz; generator level 40 dBµV.
ATR4255P
4883B–AUDR–01/06
ATR4255P
Figure 8-3.
Multipath Sensor Frequency Response
Sensor Output Voltage (V)
5.0
4.5
90% at +85˚C
90% at +25˚C
4.0
90% at -40˚C
3.5
3.0
2.5
60% at +85˚C
60% at +25˚C
60% at -40˚C
2.0
1.5
1.0
0.5
0.0
100
1000
10000
100000
AM Modulation Frequency (Hz)
Note:
Generator level 40 dBµV.
Figure 8-4.
Deviation Sensor
5
Deviation Sensor
Output Voltage (V)
4
+85˚C
3
2
-40˚C
1
0
0
20000
40000
60000
80000
100000
Frequency Deviation (Hz)
Note:
FM modulation frequency: 1 kHz; BW setting 2nd IF filter = 120 kHz.
Figure 8-5.
Deviation Sensor Frequency Response
Sensor Output Voltage (V)
1.0
0.5
0.0
100
1000
10000
100000
FM Modulation Frequency (Hz)
Note:
FM frequency deviation: 22.5 kHz.
29
4883B–AUDR–01/06
FM Input Level Sweep
10
5
0
4.5
MPX Output (dB)
Signal
-10
4
-20
3.5
Sensor output
-30
3
-40
2.5
-50
2
Noise
-60
Field Strength Sensor
Output Voltage (V)
Figure 8-6.
1.5
-70
-20
0
20
40
60
80
100
1
120
Input Level (dBµV)
Soft mute threshold, bits 68 and 69 = 0, bit 70 = 1; soft mute gain, bit 67 = 1,
gain FM IF amplifier, bit 89 = 1, bits 90 and 91 = 0.
Figure 8-7.
Selectivity
20
4.5
Pdes/Pundes (dB)
10
4
Pdes/Pundes
0
3.5
-10
3
-20
2.5
-30
2
-40
1.5
Adjacent
-50
1
-60
0.5
-70
-250
-200
-150
-100
-50
0
50
100
150
200
Adjacent Channel Output
Voltage (V)
Note:
0
250
Frequency Offset (kHz)
Note:
30
Integrated bandfilter BW setting: 120 kHz
Desired signal level adjusted to 40 dB SNR without undesired signal,
undesired signal level adjusted to 26 dB SNR.
ATR4255P
4883B–AUDR–01/06
ATR4255P
Figure 8-8.
Test Circuit
Test Point
1
44
2
43
3
42
VS
4
41
P41
10n
5
40
6
39
7
38
8
37
9
36
10
35
11
34
330
VS
VS
4n7
1k
270
2k2
100
600
100n
100p
P29
100n
10
15p
100n
10n
2n2
100n
10n
100n
12
6p8
100n
13
ATR4255P
P41
200k
33
100n
32
47p
10k
5k6
P29
P31
14
31
15
30
16
29
22p
1n
V
P29
22n
10k
220n
10k
Bus
17
28
18
27
19
26
20
25
21
24
220n
Pin1
ATR4256
Pin19
Pin15
10n
10k
VS
10n
22
82p
2k2
23
31
4883B–AUDR–01/06
32
4µ7
L301
220n
C315
R306
470k
220n
C316
S391D
FM 75Ω D302
Ant
R307
47
T111
J109
T302
BC848
L303
2m2
2k2
R311
6p8
C319
S391D
D301
10n
C302
2k2
R308
R105
100
100n
C311
BC
858C
T301
T102
BC858
100 µH
L302
2µ2
C106
L102
10p
C113
100n
3p9
C102
F201
2
43
1n
C56
D101
S391D
10n
D103 C103
F101
10n
BB804
27p
C104
18p
C107
6p8
C108 C109
1
44
100p
C in F201
BB804
D102
T101
BFR93A
R112 47k
R104
470
F102
68k
R102
390
R313
470n
C111
C112
10µ
R103
1k
10n
C117
R115
1k
12p
C306
10n
C209
R29
10
4
41
68k
R122
68k
R121
C314
10n
C110
4n7
3
42
10n
C307
100n
C201
5
40
C308
100n
6
39
R34
27
7
38
9
C116
100n
12
R151
8k2
14
15
30
22p
1n
C152
330p
C134
R131
5k6
BB804
F131
47p
1
20
C131 C132
13
31
220n
C207
220n
C208
32
D131
C133
6p8
220n
C114
11
100n
10
33
X301
ATR4255P
10µ
35
34
C205
10n
C206
1k5
R305
C115
22µ
C203
8
36
470n
C204
R111
200k
C202
37
1µ
KR201
R304
1k3
3
18
17
28
C158
10n
10n
C151
2
19
16
29
KR202
4
17
18
27
16
19
26
20
25
10n
C159
DAC3
5
21
15
6
1n
10n
C312
8
13
9
12
Q151
12p*
10
11
12p*
10.25 MHz
C153 C154
22
23
F302
R106
10
10n
C157
SWO1
SWO3
SWO2
SWO4
7
14
100n
R303
1k
C310
24
C155
C156
10n
C309
220n
ATR4256
KF302
GND
EN
CLK
DATA
IF2OUT
INT
DEV
MULTIP
VS (+8.5V
to 10.5V)
METER
ADJAC
MPX
*depends on Q151
R152
10
10
R407
Figure 8-9.
Application Circuit
ATR4255P
4883B–AUDR–01/06
ATR4255P
9. Ordering Information
Extended Type Number
Package
Remarks
ATR4255P-ILSY
SSO44
Tube, lead-free
ATR4255P-ILQY
SSO44
Taped and reeled, lead-free
10. 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
33
4883B–AUDR–01/06
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4883B–AUDR–01/06