LM1865N National Semiconductor, LM1865N Datasheet - Page 6

• Manufacturer Part Number: LM1865N
• Description: ADVANCED FM IF SYSTEM
• Manufacturer: National Semiconductor

Specifications of LM1865N

• Function: FM IF System
• Rf Type: FM
• Package / Case: 20-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *LM1865N; LM1865

Typical Application
LAYOUT CONSIDERATIONS
Although the pinout of the LM1865 has been chosen to min-
imize layout problems some care is required to insure sta-
bility The ground terminal on CF1 should return to both
PERFORMANCE CHARACTERISTICS OF TYPICAL
APPLICATION WITH TUNER
The following data was taken using the typical application
circuit in conjunction with an FM tuner with 43 dB of gain a
30 dB quieting
Level stop mute threshold
Deviation mute window (
b
3 dB limiting
Meter Output and
Signal-to-Noise
vs Tuner Input
e
e
1 4 V
0 9 V
b
3 dB)
e
1 4 V
e
g
45 kHz
PC Layout (Component Side)
Total Harmonic Distortion vs
Tuner Input
6
the input signal ground and the buffer ground pin 19 The
ground terminal on CF2 should return to the ground side of
C4 The quadrature coil T1 and inductor L1 should be sepa-
rated from the input circuitry as far as possible
5 5 dB noise figure and 30 dB of AGC range The tuner was
driven from a 50
on the audio output pin 15 The 0 dB reference is for
kHz deviation at 400 Hz modulation
source 75 s of de-emphasis was used
AM Rejection vs Tuner
Input
TL H 7509 – 6
TL H 7509 – 7
g
75