TDA7421N Datasheet, PDF (10/38 Pages) STMicroelectronics – AM/FM TUNER FOR CAR RADIO AND HI-FI APPLICATIONS

TDA7421N
ELECTRICAL CHARACTERISTICS (Continued)
Symbol
G_DEM
Parameter
Demodulator Conversion Gain
Test Condition
V_FMLIMIN > LS
Min.
G_DEMADJ Demodulator Adjustment
Conversion Gain
V_FMLIMIN > LS
CAdjDem Value of the minimum adjusting DEM6-0 set to 0000001
capacitance step
FM Audio Amplifier
Ref: FM Test circuit, V_FMLIMIN, = 95dBµV, f_IN = 10.7MHz; measure:
- MPX output at V_AUDIO, BPF 200Hz to 15KHz, 50µs de-emphasis.
- muting voltage at V_{MUTE, DRIVE}
V_MUTE Mute Voltage
V_MUTE,DRIVE for which
2
∆V_AF = -11.5dB;
AUM1-0 set to 11
V_PLAY Play Voltage
G_AMP,PLAY Audio Amplifier Gain in Play
Conditions
V_MUTE,DRIVE for which
∆V_AF = -1dB, AUM1-0 set to 11
V_MUTE,DRIVE < V_PLAY
MUTEATT_MIN Minimum Mute Attenuation
V_MUTE,DRIVE > V_MUTE;
AUM1-0 set to 00
MUTEATT_MAX Maximum Mute Attenuation
V_MUTE,DRIVE > V_MUTE;
AUM1-0 set to 11
V_AF
THD
AF Output Level
AF Total Harmonic distortion
f_DEV = 75KHz, F_MOD = 1KHz,
V_MUTE,DRIVE < V_MUTE
f_{DEV = 40KHz, FMOD = 1KHz,}
V_MUTE,DRIVE < V_MUTE
S+N/N AF Signal to Noise Ratio
f_DEV = 40KHz, F_MOD = 1KHz,
V_MUTE,DRIVE < V_MUTE
AMR
Amplitude Modulation Rejection
AM modulation depht 30%,
f_MOD = 1KHz, with respect to FM
modulated signal with f_DEV =
40KHz, V_MUTE,DRIVE < V_MUTE
AUDIO_curr Output Current Capability
5
MUTE R_out Mute Drive Output Resistance
FM QUALITY DETECTORS
Field Strength Detector
Ref: FM Test Circuit, HDDIS and BWDIS set to 1, measure:
- Input at V_FMLIMIN, f_IN = 10.7MHz, CW
- output at V_MUTE,DRIVE
FSD_MIN Field Strength Detector
Minimum Threshold
V_FMLIMIN level at which
V_MUTE,DRIVE = V_MUTE, FSM3-0
set to 0000
Typ.
2
14
50
9
-5
-12.5
400
0.3
80
67
1
Max. Unit
mV_RMS/
KHz
mV_RMS/
KHz
fF
V
0.3
V
dB
dB
dB
mV_RMS
%
dB
dB
mA
KΩ
dBµV
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