MC13156DW Freescale Semiconductor, MC13156DW Datasheet - Page 12

• Manufacturer Part Number: MC13156DW
• Manufacturer: Freescale Semiconductor

Specifications of MC13156DW

• Pin Count: 24
• Screening Level: Industrial
• Package Type: SOIC W
• Lead Free Status / Rohs Status: Supplier Unconfirmed

ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005
Component Selection
specific components, while also being versatile enough to
use components from various manufacturers and coil types.
Figures 18 and 19 show the placement for the components
specified in the application circuit (Figure 17). The
applications circuit schematic specifies particular
components that were used to achieve the results shown in
the typical curves and tables but equivalent components
should give similar results.
Input Matching Networks/Components
schematic is passive high pass network which offers effective
image rejection when the local oscillator is below the RF input
frequency. Silver mica capacitors are used for their high Q
and tight tolerance. The PC board is not dedicated to any
particular input matching network topology; space is provided
for the designer to breadboard as desired.
transformers or BALUN
The 12 dB SINAD sensitivity using the above matching
networks is typically –100 dBm for f mod = 1.0 kHz and
f dev = 75 kHz at f IN = 144.45 MHz and f OSC = 133.75 MHz
(see Figure 25).
provide additional selectivity and adjacent channel rejection
and improved sensitivity. The SAW filter should be designed
to interface with the mixer input impedance of approximately
1.0 k . Table 1 displays the series equivalent single–ended
mixer input impedance.
Local Oscillators
VHF Applications – The local oscillator circuit shown in the
application schematic utilizes a third overtone crystal and an
RF transistor. Selecting a transistor having good phase noise
performance is important; a mandatory criteria is for the
12
The evaluation PC board is designed to accommodate
The input matching circuit shown in the application circuit
Alternate matching networks using 4:1 surface mount
It is desirable to use a SAW filter before the mixer to
(Single–ended configuration, V CC = 3.0 Vdc, local oscillator drive = 100 mVrms)
S
Frequency
provide satisfactory performance.
(MHz)
100
110
120
130
140
150
160
170
180
190
90
Freescale Semiconductor, Inc.
For More Information On This Product,
Table 1. Mixer Input Impedance Data
Complex Impedance
APPLICATIONS INFORMATION
Series Equivalent
Go to: www.freescale.com
190 – j380
160 – j360
130 – j340
110 – j320
97 – j300
82 – j280
71 – j270
59 – j260
52 – j240
44 – j230
38 – j220
(R + jX)
( )
MC13156
device to have good linearity of beta over several decades of
collector current. In other words, if the low current beta is
suppressed, it will not offer good 1/f noise performance. A
third overtone series resonant crystal having at least 25 ppm
tolerance over the operating temperature is recommended.
The local oscillator is an impedance inversion third overtone
Colpitts network and harmonic generator. In this circuit a 560
to 1.0 k resistor shunts the crystal to ensure that it operates
in its overtone mode; thus, a blocking capacitor is needed to
eliminate the dc path to ground. The resulting parallel LC
network should “free–run” near the crystal frequency if a
short to ground is placed across the crystal. To provide
sufficient output loading at the collector, a high Q variable
inductor is used that is tuned to self resonate at the 3rd
harmonic of the overtone crystal frequency.
HF and VHF local oscillator with higher order overtone
crystals. Figure 20 shows a 5th overtone oscillator at
93.3 MHz and Figure 21 shows a 7th overtone oscillator at
148.3 MHz. Both circuits use a Butler overtone oscillator
configuration. The amplifier is an emitter follower. The crystal
is driven from the emitter and is coupled to the high
impedance base through a capacitive tap network. Operation
at the desired overtone frequency is ensured by the parallel
resonant circuit formed by the variable inductor and the tap
capacitors and parasitic capacitances of the on–chip
transistor and PC board. The variable inductor specified in
the schematic could be replaced with a high tolerance, high Q
ceramic or air wound surface mount component if the other
components have good tolerances. A variable inductor
provides an adjustment for gain and frequency of the
resonant tank ensuring lock up and startup of the crystal
oscillator. The overtone crystal is chosen with ESR of
typically 80
crystal is too high, the performance of the oscillator may be
impacted by lower gain margins.
The on–chip grounded collector transistor may be used for
Resistance
Parallel
1020
1040
1030
1040
1200
1250
1300
1100
1160
( )
Rp
950
970
MOTOROLA WIRELESS SEMICONDUCTOR
and 120
SOLUTIONS – RF AND IF DEVICE DATA
Capacitance
maximum; if the resistive loss in the
Parallel
(pF)
Cp
4.7
4.4
4.2
4.2
4.0
4.0
4.0
3.9
3.9
3.8
3.8