U4255BM-MFN Atmel, U4255BM-MFN Datasheet - Page 3

• 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: -

Figure 2. Block Diagram
Functional
Description
Reception Mode
4519A–AUDR–03/02
AMVREG
GNDOSC
MX1AMA
MX1AMB
OSCOUT
MX1FMB
MX1FMA
AMAGC
GNDMX
OSCE
OSCB
41
3
4
2
1
16
15
14
13
7
6
AMPLPF
OSC
FM
AGC
8
MX1OA
EN
Divider
17 18 19
CLK
Bus
AM
43
MX1OB
DATA
44
IF1FMI
AGC
FMAGC
The U4255BM-M 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 1
mented 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.
The bus protocol and the bit-to-register mapping is described in the section ’3-wire Bus
Description’. The meaning of the control bits is mentioned in the following sections.
The IC can be operated in four different modes. Mode AM, FM, WB, Standby are
selected by means of Bit 92 and Bit 93 according to Table 1.
In AM mode the AM mixer, the AM RF-AGC and the 1
activated. The input of the 2
2
available at MPX output Pin 11.
38
5
nd
IF1REF
V57
39
IF amplifier is fed to the AM demodulator. The output of the AM demodulator is
FM
V3
Bandgap
12 25 42
IF1AMI
AM
GND
33
VS
IF1OUT
METER
V3
30 29
9
V3
MX2IN
26
MX2OB
MX2LO
23
22
MX2OA
24
Adj.
chan
.
st
nd
ADJAC
mixer. Automatic gain control (AGC) circuits are imple-
IF2IN
IF amplifier is connected to Pin 28 and the output of the
10
28
Stop
V3P
27
INT
INT
21
Multi-
path
MULTIP
40
AGC
IF2OUT
FM
dem.
20
AM
dem.
Soft
mute
st
SMUTE
IF AM amplifier at Pin 33 are
Automatic
adjustment
34
Dev.
ana.
DEV
31
U4255BM-M
32
36
35
37
11
OPLPF
IFAGCL
IFAGCCH
FMADJ
MPX
3