TDA7421 Datasheet, PDF (12/38 Pages) STMicroelectronics – AM/FM TUNER FOR CAR RADIO AND Hi-Fi APPLICATIONS

TDA7421
ELECTRICAL CHARACTERISTICS (continued)
AM IF2 Amplifier
Ref: AM Test Circuit, measure input at VIP2AMPIN, output at VIP2AMPOUT, (switches must be in position 1),
fIN = 450KHz.
Symbol
RIN,IF2AMP
GIF2AMP
AGCAMPCP
AGCAMPSP
Parameter
Input Resistance
Maximum Gain
Central Point of AGC2 Intevention
on IF2 Amp
AGC2 Starting Point on IF2 Amp
AGCAMPR AGC2 Range on IF2 Amp
AGCTCR AGC2 Time Constant Ratio
IFAMST AM IF2 Output Level at pin 28
IFAMSTcurr Current Capability of pin 28
Test Condition
Min.
VIF2AMPIN = 10dBu
VIF2AMPIN = 72dBu; Value of
VIF2AMPOUT
Value of VIF2AMPIN for which
VIF2AMPOUT is AGCAMPCP - 3dB
fIN = 10.7MHz; Range of
36
VMIX2AMIN = for which VMIX2OUT is
AGCMIXCP ±3dB
Ratio of AGC2 "reception" Time
Constant and "seek" Time Constant
VIF2AMPIN = 72dBu;
104
AMSTEREO set to 1
AMSTEREO set to 1
Typ.
2
51
115
Max.
63
150/5
106 108
150
Unit
KΩ
dB
dBu
dBu
dB
s/s
dBu
µA
AM Field Strength Meter and Field Strength Station Detector
Ref: AM Test Circuit, measure at VMIX2AMIN, outputs at VAMSMETER and at VAMSD (switches in position 2),
- fIN = 10.7KHz.
- AMSEEK set to 1
Symbol
AMSM1
AMSM2
AMSM3
AMSDMIN
AMSDMAX
Parameter
AM Smeter 1 at VAMSMETER
AM Smeter 2 at VAMSMETER
AM Smeter 3 at VAMSMETER
Station Detector Minimum
Threshold
Station Detector Maximum
Threshold
Test Condition
VMIX2AMIN = 35dBu
VMIX2AMIN = 65dBu
VMIX2AMIN = 95dBu
VMIX2AMIN at which VAMSD = 2.5V,
ASS3-0 set to 0000
VMIX2AMIN at which VAMSD = 2.5V,
ASS3-0 set to 1111
Min. Typ. Max
2.2 2.89 3.6
2.5 3.26 4.0
3.0 3.73 4.5
44
64
Unit
V
V
V
dBu
dBu
IF Counter Output
Ref: AM & FM Test Circuit, measure at pin 28
Symbol
IFCFM
Parameter
FM IFC Sensitivity
IFCAM AM IFC Sensitivity
IFCcurrent IFC Current Capability
Test Condition
Min. Typ. Max Unit
VFMLIMIN at which Vpin 28 = 2.5V,
34
dBu
FMRECSEEK set to 1, EW2-0 set
to 101, IFS2-0 set to 010
VIF2AMPIN at which Vpin 28 = 2.5V,
29
dBu
AMSEEK set to 1, EW2-0 set to
011, IF2-0 set to 100, AMFM
STBY1-0 set to 10
150
µA
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