U4255BM-MFN Atmel, U4255BM-MFN Datasheet - Page 8

• Manufacturer Part Number: U4255BM-MFN
• Description: IC RCVR AM/FM FRONT-END 44-SSOP
• Manufacturer: Atmel

Specifications of U4255BM-MFN

• Frequency: 70MHz ~ 160MHz
• Modulation Or Protocol: AM, FM
• Applications: AM/FM Radio Receiver
• Current - Receiving: 50mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Voltage - Supply: 7.5 V ~ 10 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-SSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Features: -
• Sensitivity: -
• Memory Size: -
• Data Rate - Maximum: -

Automatic IF Center
Frequency Adjustment
8
U4255BM-M
Table 11. Pin 20 Output Setting
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
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 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 if Bit 4 is set to 1. If Bit 4 is set to 0, the
default setting is used.
Table 12. 2
450.00 kHz
456.25 kHz
461.50 kHz
468.75 kHz
475.00 kHz
481.25 kHz
487.50 kHz
493.75 kHz
450.00 kHz
443.75 kHz
437.50 kHz
431.25 kHz
425.00 kHz
418.75 kHz
412.50 kHz
406.25 kHz
IF Center
nd
IF Center Frequency
10.25MHz
Pin 22
Multipath field strength
Pin 37
2
nd
Pin 20
IF output
Bit 56...59
adjustment
Frequency
Automatic
Bit 59
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Bit 14...17
Bit 58
Bit 5,6
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
+
+
center
center
center
freq.
freq.
freq.
adj.channel
FM-Demod
bandfilter
Sensor
Bit 57
FM-
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
Bit 55
4519A–AUDR–03/02
0
1
Bit 56
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1