Features
High Dynamic Range for AM and FM
Integrated AGC for AM and FM
High Intercept Point 3rd Order for FM
FM Amplifier Adjustable to Various Cable Impedances
High Intercept Point 2nd and 3rd Order for AM
Low Noise Output Voltage
Low Power Consumption
Low Output Impedance AM
Low-noise,
1. Description
High-dynamic-
The ATR4251 is an integrated low-noise AM/FM antenna amplifier with integrated
range AM/FM
AGC in BiCMOS2S technology. The device is designed in particular for car applica-
tions, and is suitable for windshield and roof antennas.
Antenna
Figure 1-1. Block Diagram QFN24 Package
Amplifier IC
FM FM FM AGC
VREF1 GND2
IN GAIN OUT IN
Paddle = GND
ATR4251
24 23 22 21 20 19
FM
NC* NC*
1 amplifier 18
GND VS
BAND
2 17
GAP
AGC1 AGC AGCCONST
3 16
AGC2 VREF4
4 15
VREF2 AMOUT1
5 14
AM
AGC
AMIN GND1
(AM)
6 13
7819 0 1112
CREG AGC AGC T NC*
NC*
AMIN AM CONST
* Pin must not be connected to any other pin or supply chain except GND.
4913JAUDR10/09Figure 1-2. Block Diagram SSO20 Package
FMGAIN 1 20 GND2
FM
amplifier
FMIN 2 19 FMOUT
VREF1 3 18 AGCIN
AGC
GND 4 17 VS
AGC1 5 16 AGCCONST
Band
gap
AGC2 6 15 VREF4
VREF2 7 14 AMOUT1
AMIN1 8 AM 13 GND1
CREG 9 12 TCONST
AGC
(AM)
AGCAMIN 10 11 AGCAM
SSO20
2
ATR4251
4913JAUDR10/09