MICRF009BM TR Micrel Inc, MICRF009BM TR Datasheet - Page 7

• Manufacturer Part Number: MICRF009BM TR
• Manufacturer: Micrel Inc

Specifications of MICRF009BM TR

• Operating Band Frequency: 300 to 440MHz
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Modulation Type: ASK/OOK
• Product Depth (mm): 3.94mm
• Product Height (mm): 1.48mm
• Product Length (mm): 9.93mm
• Operating Supply Voltage (min): 4.75V
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.5V
• Lead Free Status / Rohs Status: Not Compliant

MICRF009, allowing the device to operate in applications
where
misalignment may exist. The transmit frequency may vary
up to ±0.5% over initial tolerance, aging, and temperature.
In sweep-mode, a band approximately 1.5% around the
nominal transmit frequency is captured. The transmitter
may drift up to ±0.5% without the need to retune the
receiver and without impacting system performance.
The swept-LO technique does not affect the IF bandwidth,
therefore noise performance is not degraded relative to
fixed-mode. The IF bandwidth is 680kHz whether the
device is operating in fixed or sweep-mode.
Due to limitations imposed by the LO sweeping process,
the
approximately 1250Hz.
Similar performance is not currently available with crystal-
based superheterodyne receivers, which can operate only
with SAW- or crystal-based transmitters.
In sweep-mode, a range reduction will occur in installation
where there is a strong interferer in the swept RF band.
This is because the process indiscriminately includes all
signals within the sweep range. An MICRF009 may be
used in place of a super-regenerative receiver in most
applications.
Step 2: Selecting The Reference Oscillator
All timing and tuning operations on the MICRF009 are
derived from the internal Colpitts reference oscillator.
Timing and tuning is controlled through the REFOSC pin in
one of three ways:
The specific reference frequency required is related to the
system transmit frequency and to the operating mode of
the receiver as set by the SWEN pin.
Crystal or Ceramic Resonator Selection
Do not use resonators with integral capacitors since
capacitors are included in the IC, also care should be taken
to ensure low ESR crystals are selected. Contact Micrel RF
Applications for suggested suppliers and part numbers.
If operating in fixed-mode, a crystal is recommended. In
sweep-mode either a crystal or ceramic resonator may be
used. When a crystal or ceramic resonator is used, the
minimum voltage is 300mV
applied signal, it should be AC-coupled and limited to the
operating range of 0.1V
Selecting Reference Oscillator Frequency f
(Fixed-Mode)
As with any superheterodynes receiver, the difference
Micrel
January 18, 2005
1. Connect a ceramic resonator.
2. Connect a crystal.
3. Drive this pin with an external timing signal.
upper
significant
limit
on
PP
data
transmitter-receiver
to 1.5V
PP
rate
. If using an externally
PP
.
in
sweep-mode
T
frequency
is
7
between the internal LO (local oscillator) frequency f
the incoming transmit frequency f
center frequency. Equation 1 may be used to compute the
appropriate f
Frequencies f
of f
mixing” and “low-side mixing.” High-side mixing results in
an image frequency above the frequency of interest and
low-side mixing results in a frequency below. There is
generally no preference of one over the other.
After choosing one of the two acceptable values of f
Equation 2 to compute the reference oscillator frequency
f
Frequency f
to REFOSC on the MICRF009. Four-decimal-place
accuracy on the frequency is generally adequate. The
following table identifies f
frequencies when the MICRF009 is operated in fixed-
mode.
Selecting REFOSC Frequency f
(Sweep Mode)
Selection of the reference oscillator frequency f
mode is much simpler than in fixed mode due to the LO
sweeping process. Also, accuracy requirements of the
frequency reference component are significantly relaxed.
In sweep mode, f
In sweep mode a reference oscillator with frequency
accurate to two-decimal-places is generally adequate. A
crystal may be used and may be necessary in some cases
if the transmit frequency is particularly imprecise.
T
Values For Typical Transmit Frequencies (high-side mixing)
:
Table 1. Fixed-Mode Recommended Reference Oscillator
LO
Transmit Frequency (f
Transmit Frequency (f
f
f
f
LO
T
T
exist for any given f
= 2 ×
= 2 ×
= f
433.92MHz
TX
315MHz
390MHz
418MHz
T
LO
64.5
64.25
± 0.86
TX
f
LO
is in MHz. Connect a crystal of frequency f
f
TX
⎛
⎜
⎝
for a given f
and f
T
is given by Equation 3:
315
f
TX
LO
⎞
⎟
⎠
TX
TX
are in MHz. Note that two values
)
)
TX
T
TX
:
for some common transmit
, distinguished as “high-side
Reference Oscillator
T
Reference Oscillator
TX
Frequency (f
Frequency (f
, should equal the IF
12.1260MHz
12.9966MHz
13.4916MHz
9.7941MHz
[phone]
M9999-011805
MICRF009
T
T
T
)
)
(1)
(2)
(3)
in sweep
LO
LO
, use
and
T