MC3356 Motorola, MC3356 Datasheet - Page 3

• Manufacturer Part Number: MC3356
• Description: GENERAL PURPOSE TRANSISTOR ARRAY
• Manufacturer: Motorola

GENERAL DESCRIPTION
VHF receiver systems, primarily for FSK data transmission
up to 500 K baud (250 kHz). It contains an oscillator, mixer,
limiting IF, quadrature detector, signal strength meter drive,
and data shaping amplifier.
be crystal controlled, as shown in Figure 1, or L–C controlled
as shown in the other figures. At higher V CC , it has been
operated as high as 200 MHz. A mixer/oscillator voltage gain
of 2 up to approximately 150 MHz, is readily achievable.
10
about 10 mVrms, before any evidence of overload.
Operation up to 1.0 Vrms input is permitted, but non–linearity
of the meter output is incurred, and some oscillator pulling is
suspected. The AM rejection above 10 mVrms is degraded.
operated up to 50 MHz. It is expected to be used at 10.7 MHz
in most cases, due to the availability of standard ceramic
resonators. The quadrature detector is internally coupled to
the IF, and a 5.0 pF quadrature capacitor is internally
provided. The –3dB limiting sensitivity of the IF itself is
approximately 50 V (at Pin 7), and the IF can accept signals
up to 1.0 Vrms without distortion or change of detector
quiescent dc level.
6 state limiter contains a signal strength sensitive, current
sinking device. These are parallel connected and buffered to
produce a signal strength meter drive which is fairly linear for
IF input signals of 10 V to 100 mVrms (see Figure 4).
meter current flowing through the meter load resistance flips
a comparator at about 0.8 Vdc above ground. The signal
strength at which this occurs can be adjusted by changing
the meter load resistor. The comparator (+) input and output
are available to permit control of hysteresis. Good positive
MOTOROLA ANALOG IC DEVICE DATA
–10
–20
–30
–40
–50
–60
10
0
This device is intended for single and double conversion
The oscillator is a common base Colpitts type which can
The mixer functions well from an input signal of
The limiting IF is a high frequency type, capable of being
The IF is unusual in that each of the last 5 stages of the
A simple squelch arrangement is provided whereby the
0.01
Vrms, below which the squelch is unpredictable, up to
Figure 3. Output Components of Signal,
Noise, and Distortion
0.1
INPUT (mVrms)
S + N + D
N + D
N
1.0
f O = 100 MHz
fm = 1.0 kHz
f = 75 kHz
10
MC3356
action can be obtained for IF input signals of above 30
a small amount of hysteresis. Its connection between the
3.3 k resistor to ground and the 3.0 k pot, permits adjustment
of squelch level without changing the amount of hysteresis.
quadrature detector and the data shaper. The quadrature
detector output, when squelched, goes to a dc level
approximately equal to the zero signal level unsquelched.
The squelch causes the data shaper to produce a high (V CC )
output.
with back to back diodes across its inputs. The output of the
quadrature detector can be fed directly to either input of this
amplifier to produce an output that is either at V CC or V EE ,
depending upon the received frequency. The impedance of
the biasing can be varied to produce an amplifier which
“follows” frequency detuning to some degree, to prevent data
pulse width changes.
demodulator output, Pin 13, there may be distortion at Pin 13
due to the diodes, but this is not important in the data
application. A useful note in relating high/low input frequency
to logic state: low IF frequency corresponds to low
demodulator output. If the oscillator is above the incoming
RF frequency, then high RF frequency will produce a logic
low (input to (+) input of Data Shaper as shown in Figures 1
and 2).
APPLICATION NOTES
requires following certain layout techniques in designing a
stable circuit configuration. The objective is to minimize or
eliminate, if possible, any unwanted feedback.
Vrms. The 130 k resistor shown in the test circuit provides
The squelch is internally connected to both the
The data shaper is a complete ‘‘floating’’ comparator,
When the data shaper is driven directly from the
The MC3356 is a high frequency/high gain receiver that
700
600
500
300
200
100
400
0
0.010
Figure 4. Meter Current versus Signal Input
0.1
PIN 20 INPUT (mVrms)
1.0
10
100
1000
3