U4255BM-MFN Atmel, U4255BM-MFN Datasheet - Page 6

• 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: -

FM 1
AM 1
2
6
nd
Mixer
st
st
IF Amplifier
IF Amplifier
U4255BM-M
Table 5. Divide Factor of the AM Prescaler
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
external ceramic filters.
Two different temperature coefficients of the FM IF amplifier can be selected by Bit 66.
Table 6. Gain of the FM IF Amplifier
Table 7. Temperature Coefficient Setting of FM IF Amplifier
In AM mode, the gain of the 1
control range of the IF-AGC.
The 2
tance 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.
Divider AM Prescaler
nd
Divide by 10
Divide by 6
Divide by 7
Divide by 8
Divide by 4
mixer is used in AM, FM and WB mode. The mixer input has 330
Temperature Coefficient (TC) of the IF Amplifier
Gain FM IF
20 dB
22 dB
24 dB
26 dB
28 dB
29 dB
30 dB
31 dB
Bit 93
TK
TK
st
1
1
1
1
1
max
min
IF amplifier is controlled by the IF-AGC to extend the
Bit 92
0
0
0
0
0
Bit 91
0
0
0
0
1
1
1
1
Bit 84
x
x
x
x
x
Bit 83
Bit 90
0
0
0
1
1
0
0
1
1
0
0
1
1
Bit 82
0
0
1
0
0
Bit 66
4519A–AUDR–03/02
0
1
input resis-
Bit 89
and fits to
0
1
0
1
0
1
0
1
Bit 81
0
1
0
0
1