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ATMEL Corporation |
Features
• High Dynamic Range for AM and FM
• Integrated AGC for FM
• High Intercept Point 3rd-order for FM
• FM Amplifier Adjustable to Various Cable Impedances
• High Intercept Point 2nd-order for AM
• Low-noise Output Voltage
• Low-power Consumption
Electrostatic sensitive device.
Observe precautions for handling.
Low-noise
AM/FM Antenna
Impedance
Matching IC
Description
The U4254BM-M is an integrated low-noise AM/FM antenna impedance matching cir-
cuit in BiCMOS technology. The device is designed specifically for car applications
and is suitable for windshield and roof antennas.
Figure 1. Block Diagram
U4254BM-M
FMIN
GND1
FMGAIN
AGC
VS
1
2
3
4
14
5
VREF2
FM
IAGC
VREF
AGC
15
FMOUT
13
AGCADJ
12
VREF1
8
AMIN
AM
7
GND2
11
AMOUT1
10
AMOUT
Rev. 4772B–AUDR–11/03
Pin Configuration
Figure 2. Pinning SO16
FMIN 1
GND1 2
FMGAIN 3
AGC 4
VREF2 5
NC 6
GND2 7
AMIN 8
16 NC
15 FMOUT
14 VS
13 AGCADJ
12 VREF1
11 AMOUT1
10 AMOUT
9 NC
Pin Description
Pin Symbol
1 FMIN
2 GND1
3 FMGAIN
4 AGC
5 VREF2
6 NC
7 GND2
8 AMIN
9 NC
10 AMOUT
11 AMOUT1
12 VREF1
13 AGCADJ
14 VS
15 FMOUT
16 NC
Function
FM input
Ground for FM part
FM gain adjustment
AGC output
Reference voltage 2 output
Not connected
Ground for AM part
AM input
Not connected
AM output
AM output
Reference voltage 1 output
Adjustment FM wide-band AGC threshold
Supply voltage
FM output
Not connected
2 U4254BM-M
4772B–AUDR–11/03
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