View U4254BM-M_62668.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

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 U4254BM-M
Description
The U4254BM-M is an integrated low-noise AM/FM antenna impedance matching circuit in BiCMOS technology. The device is designed specifically for car applications and is suitable for windshield and roof antennas. Figure 1. Block Diagram
FMIN GND1 FMGAIN AGC VS
1 2 3 4 14 IAGC
FM
15
FMOUT
AGC
13 AGCADJ
VREF2
5
VREF
12 VREF1
11 AMIN 8
AMOUT1 AMOUT
AM
7 GND2
10
Rev. 4772B-AUDR-11/03
Pin Configuration
Figure 2. Pinning SO16
FMIN
1 2
16 NC 15 FMOUT 14
VS
GND1
FMGAIN 3 AGC VREF2 NC
4 5 6 7 8
13 AGCADJ 12 VREF1 11 AMOUT1 10 AMOUT 9
NC
GND2 AMIN
Pin Description
Pin 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Symbol FMIN GND1 FMGAIN AGC VREF2 NC GND2 AMIN NC AMOUT AMOUT1 VREF1 AGCADJ VS FMOUT 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
U4254BM-M
Pin Description
FMIN
FMIN, a bipolar transitor's base is the input of the FM amplifier. A resistor or a coil is connected between FMIN and VREF2. If a coil is used, the noise performance is excellent.
Figure 3. Internal Circuit at Pin FMIN
1
FMIN ESD
GND1 FMGAIN
To avoid cross-talk between AM and FM signals, the circuit has two separate ground pins. GND1 is the ground for the FM part. The DC current of the FM amplifier transistor is adjusted by an external resistor which is connected between FMGAIN and GND1. To influence the AC gain of the amplifier, a resistor is connected in series to a capacitor between FMGAIN and GND1. The capacitor has to shorten frequencies of 100 MHz.
Figure 4. Internal Circuit at pin FMGAIN
ESD FMGAIN 3
AGC
DC current flows into the AGC pin at high FM antenna input signals. This current has to be amplified via the current gain of an external PNP transistor that feeds a PIN diode. This diode dampens the antenna's input signal and protects the amplifier input against overload. The maximum current which flows in the AGC pin is approximately 1 mA. In low-end applications, the AGC function is not necessary and the external components can therefore be omitted.
3
4772B-AUDR-11/03
Figure 5. Internal Circuit at Pin AGC
AGC 4
ESD
VS
AGCADJ
The threshold of the AGC can be adjusted by varying the DC current at pin AGCADJ. If pin AGCADJ is connected directly to GND1, the threshold is set to 96 dBV at the FM amplifier output. If a resistor is connected between AGCADJ and GND1, the threshold is shifted to higher values with increasing resistances. If AGCADJ is open, the threshold is set to 106 dBV.
Figure 6. Internal Circuit at Pin AGCADJ
65 k
ESD 13 AGCADJ
FMOUT
The FM amplifier output is an open collector of a bipolar RF transistor. It should be connected to VS via a coil.
Figure 7. Internal Circuit at Pin FMOUT
15 FMOUT
ESD
4
U4254BM-M
4772B-AUDR-11/03
U4254BM-M
AMIN
The AM input has an internal bias voltage. The DC voltage at this pin is VRef1/2. The input resistance is about 470 k. The input capacitance is less than 10 pF.
Figure 8. Internal Circuit at Pin AMIN
VREF1/2
470 k 8
AMIN ESD
AMOUT, AMOUT1
The buffered AM amplifier consists of a complementary pair of CMOS source followers. The transistor gates are connected to AMIN. The pin AMOUT is the NMOS transistor's source, pin AMOUT1 is the PMOS transistor's source. Due to the two different DC levels of these pins, they have to be connected together via an external capacitor of about 100 nF. By means of this technique an excellent dynamic range can be achieved.
Figure 9. Internal Circuit at Pins AMOUT1 and AMOUT
AMOUT1 ESD 11
AMOUT ESD 10
VREF1
VREF1 is the stabilized voltage for the AM amplifier and the AGC block. To achieve excellent noise performance at LW frequencies, it is recommended that this pin be connected to ground via an external capacitor of about 1 F.
5
4772B-AUDR-11/03
Figure 10. Internal Circuit at Pin VREF1
VS
12 VREF1 ESD
GND1
VREF2
For the DC biasing of the FM amplifier, a second voltage reference circuit is integrated. Since the collector current is temperature independent, the output voltage has a negative temperature coefficient of about -1 mV/K. To stabilize this voltage, an external capacitor to ground of a few nF is recommended.
Figure 11. Internal Circuit at Pin VREF2
5
VREF2
ESD GND1
GND2
GND2 is the ground for the AM amplifier.
6
U4254BM-M
4772B-AUDR-11/03
U4254BM-M
Functional Description
The U4254BM-M is an integrated AM/FM antenna impedance matching circuit. It compensates cable losses between the antenna (for example windshield, roof or bumper antennas) and the car radio which is usually placed far away from the antenna. The FM amplifier provides excellent noise performance. External components are used to adjust the gain and the input-output matching impedance. Therefore, it is possible to adjust the amplifier to various cable impedances (usually 50, 75 or 150 ). To protect the amplifier against input overload, an Automatic Gain Control (AGC) is included on the chip. The AGC observes the AC voltage at the FM amplifier output, rectifies this signal, and delivers DC current to dampen the input antenna signal via an external PIN diode. The threshold for the AGC is adjustable. Simple and temperature-compensated biasing is possible due to the integrated voltage reference VRef2. The AM part consists of a buffer amplifier. The voltage gain of this stage is approximately one. The input resistance is 470 k, the input capacitance less than 10 pF. The output resistance is 125 . An excellent dynamic range is achieved due to the complementary CMOS source follower stage.
Absolute Maximum Ratings
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Reference point is ground (pins 2 and 7) Parameters Supply voltage Power dissipation, Ptot at Tamb = 85 C Junction temperature Ambient temperature Storage temperature Electrostatic handling (HBM at ESD S.5.1) Symbol VS Ptot Tj Tamb Tstg VESD Value 8.8 460 150 -40 to +85 -50 to +150 1000 Unit V mW C C C V
Thermal Resistance
Parameters Junction ambient Symbol RthJA Value 140 Unit K/W
7
4772B-AUDR-11/03
Electrical Characteristics
VS = 8 V, Tamb = 25 C, unless otherwise specified (see Figure 12 on page 9).
Parameters Supply voltage Supply currents Reference voltage 1 output (I12 = 0) Reference voltage 2 output (I5 = 0) Temperature dependence of VREF2 AM Amplifier Input resistance Input capacitance Output resistance Voltage gain S1 switched to 2 B = 6 kHz 150 kHz to 300 kHz 500 kHz to 6.5 kHz S2 switched to 1 fAMIN = 500 kHz Output voltage = 110 dBV IAGC, IAGCADJ = 0 A f = 100 MHz f = 100 MHz f = 100 MHz f = 100 MHz B = 120 kHz f = 100 MHz f = 100 MHz S2 switched to 1; AGC threshold DC current is 10 A at pin 4 f = 100 MHz, S2 switched to 2; AGC threshold DC current is 10 A at pin 4 AGC active 8 8 10 8, 10 RAMIN CAMIN ROUT a 125 0.85 470 10 k pF Test Conditions Pin 14 14 12 5 5 Symbol VS IS VRef1 VRef2 VRef2/T Min. 7.2 3.5 5.1 2.3 Typ. 8 4.8 5.4 2.6 -1 Max. 8.8 5.6 5.7 2.8 Unit V mA V V mV/K
Output noise voltage (rms value)
10
VN1 VN2
-2 -6
dBV dBV
2nd harmonic
10
-65
dBc
FM Amplifier Supply current limit Input resistance Output resistance Power gain Output noise voltage 3rd-order output intercept AGC 15 Vth1 96 dBV 15 1 15 1, 15 15 15 I15 RFMIN RFMOUT G VN 33 50 50 5 0 132 35 mA dB dBV dBV
AGC input voltage threshold
15 Vth2 106 dBV
AGC input voltage threshold
AGC output current
IAGC
1.2
mA
8
U4254BM-M
4772B-AUDR-11/03
U4254BM-M
Figure 12. Test Circuit
VS
1 FMOUT 2.2 H
2 S2 5 k
2.2 nF I14 I3 2.2 F + 9 100 nF 100 nF
AMOUT
I15 2.2 nF
16 150
1 I4 FMIN 2.2 nF 2.2 H 51 22 VS 2.2 nF 1
8
S1 2 15 pF
1 nF 2.2 nF AMIN
9
4772B-AUDR-11/03
Figure 13. FM Intermodulation Distortion
dBV Input 103 dBV dBV Output 108 dBV
58 dBV Gain = 5 dB AGC not active
90
95
100
105
MHz
90
95
100
105
MHz
dBV
Input 118 dBV
dBV Output 100 dBV
AGC active
50 dBV
90
95
100
105
MHz
90
95
100
105
MHz
10
U4254BM-M
4772B-AUDR-11/03
U4254BM-M
Figure 14. Test Circuit for AM Large Signal Behavior
Analyzer 100 nF
AMOUT1 LPF AMIN 1 nF fcutoff = 500 kHz 50 AMOUT DUT
5 k 100 nF
Rin = 50
115 dBV 50 f = 500 kHz V0
75 dBV
Figure 15. AM Harmonic Distortion
VAMOUT (dBV) 110 115 dBV
90
70 55 dBV 50 0.5 1.0 45 dBV 1.5 f (MHz)
11
4772B-AUDR-11/03
Figure 16. Application Circuit
12
VS = 8.2 V 2.2 nF R1 2.2 H 2.2 nF FMIN FMOUT FM 2.2 nF FMGAIN 51 AGC AGC IAGC VS 1 k VREF2 VRef 2.2 nF Vs VREF1 + 1 F 100 nF AMOUT1 AMIN 1 nF AMGND AM AMOUT 100 nF 2.2 H AGCADJ Output R2 FMGND 39 pF R1 () 150 270 390 470 620 33 51 86 160 22 R2 ()
ANTENNA
AM
FM
PIN
U4254BM-M
BA679
2.2 nF
510
BC558
200 nF
V
Protection circuit
R1 and R2 depend on used FM cable impedance
FM cable impedance
50
75
100
125
4772B-AUDR-11/03
150
U4254BM-M
Ordering Information
Extended Type Number Package Remarks
U4254BM-MFP U4254BM-MPG3
SO16 SO16
- Taping corresponding, ICE-286-3
Package Information
Package SO16
Dimensions in mm
10.0 9.85 5.2 4.8 3.7
1.4 0.4 1.27 8.89 16 9 0.25 0.10 0.2 3.8 6.15 5.85
technical drawings according to DIN specifications
1
8
13
4772B-AUDR-11/03
Atmel Corporation
2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 487-2600
Atmel Operations
Memory
2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314
RF/Automotive
Theresienstrasse 2 Postfach 3535 74025 Heilbronn, Germany Tel: (49) 71-31-67-0 Fax: (49) 71-31-67-2340 1150 East Cheyenne Mtn. Blvd. Colorado Springs, CO 80906, USA Tel: 1(719) 576-3300 Fax: 1(719) 540-1759
Regional Headquarters
Europe
Atmel Sarl Route des Arsenaux 41 Case Postale 80 CH-1705 Fribourg Switzerland Tel: (41) 26-426-5555 Fax: (41) 26-426-5500
Microcontrollers
2325 Orchard Parkway San Jose, CA 95131, USA Tel: 1(408) 441-0311 Fax: 1(408) 436-4314 La Chantrerie BP 70602 44306 Nantes Cedex 3, France Tel: (33) 2-40-18-18-18 Fax: (33) 2-40-18-19-60
Biometrics/Imaging/Hi-Rel MPU/ High Speed Converters/RF Datacom
Avenue de Rochepleine BP 123 38521 Saint-Egreve Cedex, France Tel: (33) 4-76-58-30-00 Fax: (33) 4-76-58-34-80
Asia
Room 1219 Chinachem Golden Plaza 77 Mody Road Tsimshatsui East Kowloon Hong Kong Tel: (852) 2721-9778 Fax: (852) 2722-1369
ASIC/ASSP/Smart Cards
Zone Industrielle 13106 Rousset Cedex, France Tel: (33) 4-42-53-60-00 Fax: (33) 4-42-53-60-01 1150 East Cheyenne Mtn. Blvd. Colorado Springs, CO 80906, USA Tel: 1(719) 576-3300 Fax: 1(719) 540-1759 Scottish Enterprise Technology Park Maxwell Building East Kilbride G75 0QR, Scotland Tel: (44) 1355-803-000 Fax: (44) 1355-242-743
Japan
9F, Tonetsu Shinkawa Bldg. 1-24-8 Shinkawa Chuo-ku, Tokyo 104-0033 Japan Tel: (81) 3-3523-3551 Fax: (81) 3-3523-7581
Literature Requests
www.atmel.com/literature
Disclaimer: Atmel Corporation makes no warranty for the use of its products, other than those expressly contained in the Company's standard warranty which is detailed in Atmel's Terms and Conditions located on the Company's web site. The Company assumes no responsibility for any errors which may appear in this document, reserves the right to change devices or specifications detailed herein at any time without notice, and does not make any commitment to update the information contained herein. No licenses to patents or other intellectual property of Atmel are granted by the Company in connection with the sale of Atmel products, expressly or by implication. Atmel's products are not authorized for use as critical components in life support devices or systems.
(c) Atmel Corporation 2003. All rights reserved. Atmel (R) and combinations thereof are the registered trademarks of Atmel Corporation or its subsidiaries. Other terms and product names may be the trademarks of others. Printed on recycled paper.
4772B-AUDR-11/03

▲Up To Search▲

Price & Availability of U4254BM-M

	To Download U4254BM-M Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .