NSC LM1868N Datasheet
LM1868 AM/FM Radio System
LM1868 AM/FM Radio System
February 1995
General Description
The combination of the LM1868 and an FM tuner will provide all the necessary functions for a 0.5 watt AM/FM radio.
Included in the LM 1868 are the audio power amplifier, FM
IF and detector, and the AM converter, IF, and detector.
The device is suitable for both line operated and 9V battery
applications.
Block Diagram
Features
Y
DC selection of AM/FM mode
Y
Regulated supply
Y
Audio amplifier bandwidth decreased in AM mode,
reducing amplifier noise in the AM band
Y
AM converter AGC for excellent overload
characteristics
Y
Low current internal AM detector for low tweet radiation
Order Number LM1868N
TL/H/7909– 1
See NS Package Number N20A
Note: See table for coil data
C
1995 National Semiconductor Corporation RRD-B30M115/Printed in U. S. A.
TL/H/7909
Absolute Maximum Ratings
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.
Supply Voltage (Pin 19) 15V
Package Dissipation 2.0W
Above T
T
Electrical Characteristics Test Circuit, T
J(MAX)
e
25§C, Derate Based on
A
e
150§C and i
e
60§C/W
JA
A
Storage Temperature Range
Operating Temperature Range 0§Ctoa70§C
Lead Temperature (Soldering, 10 sec.) 260§C
e
25§C, V
e
S
9V, R
e
8X (unless otherwise noted)
L
Parameter Conditions Min Typ Max Units
STATIC CHARACTERISTICS e
AM
e
0, e
FM
e
0
Supply Current AM Mode, S1 in Position 1 22 30 mA
Regulator Output Voltage (Pin 16) 3.5 3.9 4.8 V
Operating Voltage Range 4.5 15
DYNAMIC CHARACTERISTICSÐAM MODE
e
1 MHz, f
f
AM
Maximum Sensitivity Measure eAMfor P
Signal-to-Noise e
Detector Output e
Overload Distortion e
Total Harmonic Distortion (THD) e
DYNAMIC CHARACTERISTICSÐFM MODE f
b
3 dB Limiting Sensitivity 15 45 mV
Signal-to-Noise Ratio e
Detector Output e
AM Rejection e
Total Harmonic Distortion (THD) e
DYNAMIC CHARACTERISTICSÐAUDIO AMPLIFIER ONLY fe1 kHz, e
e
1 kHz, 30% Modulation, S1 in Position 1, P
mod
Maximum Volume
AM
AM
Measure at Top of Volume Control
AM
AM
FM
FM
FM
Measure at Top of Volume Control
FM
FM
e
50 mW unless noted
O
e
50 mW,
O
e
10 mV 40 50 dB
e
1mV
e
50 mV, 80% Modulation 2 10 %
e
10 mV 1.1 2 %
e
10.7 MHz, f
e
10 mV 50 64 dB
e
10 mV, Df
e
10 mV, 30% AM Modulation 40 50 dB
e
10 mV 1.1 2 %
mod
e
e
g
22.5 kHz
400 Hz, Df
e
AM
816mV
40 60 85 mV
e
g
75 kHz, P
e
50 mW, S1 in Position 1
O
40 60 85 mV
e
0, e
0, S1 in Position 2
FM
Power Output THDe10%, RL8X
e
6V 250 325 mW
V
S
e
9V 500 700 mW
V
S
Bandwidth AM Mode, P
FM Mode, P
Total Harmonic Distortion (THD) P
e
O
e
50 mW 11 kHz
O
e
50 mW 22 kHz
O
50 mW, FM Mode 0.2 %
Voltage Gain 41 dB
b
55§Ctoa150§C
Typical Performance Characteristics (Test Circuit) All curves are measured at audio output
Quiescent Supply Current
vs Voltage
FM Limiting Characteristics FM IF AM Rejection
2
TL/H/7909– 2
Typical Performance Characteristics (Continued)
All curves are measured at audio output (Test Circuit)
AM Characteristics
Recovered Audio vs Supply Amplifier Only
Gain vs Frequency Audio
Power Dissipation vs Power
Output, R
Test Circuit
e
8X
L
Power Dissipation vs Power
e
Out, R
16X
L
Distortion vs Frequency
Audio Amplifier Only
TL/H/7909– 3
Note: See table for coil data TL/H/7909– 4
3
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