MICRF405YML TR Micrel Inc, MICRF405YML TR Datasheet - Page 22

868-915 MHz ISM Band Transmitter

MICRF405YML TR

Manufacturer Part Number
MICRF405YML TR
Description
868-915 MHz ISM Band Transmitter
Manufacturer
Micrel Inc
Datasheet

Specifications of MICRF405YML TR

Frequency
290MHz ~ 980MHz
Applications
ISM
Modulation Or Protocol
ASK, FSK
Data Rate - Maximum
200 kbps
Power - Output
10dBm
Current - Transmitting
18mA
Data Interface
PCB, Surface Mount
Antenna Connector
PCB, Surface Mount
Voltage - Supply
2.2 V ~ 3.6 V
Operating Temperature
-40°C ~ 125°C
Package / Case
24-MLF®, QFN
Operating Temperature (min)
-40C
Operating Temperature (max)
125C
Operating Temperature Classification
Automotive
Product Depth (mm)
4mm
Product Length (mm)
4mm
Operating Supply Voltage (typ)
2.5/3.3V
Operating Supply Voltage (max)
3.6V
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Features
-
Memory Size
-
Lead Free Status / Rohs Status
Compliant
Other names
576-1965-2
MICRF405YMLTR
MICRF405YMLTR
April 2006
VCO
The VCO has no external components. It oscillates
at 1.8 GHz and is divided by 2, 4 and 6 in the 900
MHz, 450 MHz or 315MHz band respectively. This
divide ratio is controlled by the Freq_Band[1:0] bits,
as shown in Table 12.
FreqBand1 FreqBand0
The VCO_IB setting is automatically set when
VCO_IB[2:0]=0. If VCO_IB[2:0] are programmed <>
0, it will overrule the automatic setting. Default and
recommended
VCO_IB[2:0]=0 for all frequencies.
The bias bits will optimize the phase noise, and the
frequency bits will control a capacitor bank in the
VCO. The tuning range, the RF frequency versus
varactor voltage, is dependent upon the VCO
frequency setting, and is shown in Figure 10. When
the tuning voltage is in the range from 1.2 to 1.6V,
then the VCO gain is at its maximum, approximately
60-80 MHz/V. It is recommended that the varactor
voltage is kept within this range. Table 15 shows the
recommended settings of VCO_freq and FreqBand
for various frequencies.
To ensure correct settings over variations, a circuit
monitoring the varactor voltage on start up is added.
When the PLL has locked, or after a timeout has
occurred if it doesn’t lock, this circuit will control the
varactor voltage. This will be performed if either the
VCO_Fr_Chk
VCO_Fr_Chk set will set the interrupts VC_HI, in
case of a too high VCO_freq setting creating a too
high varactor voltage, and VC_LO, in case of a too
0001011
0010110
0011000
A6..A0
Adr
0
0
1
INT_LF_TEST=0
LowBatt_en=1
VCO_freq_O2
Table 12. Frequency Band.
D7
X
0
1
or
for
VCO_Fr_Auto
Freq_Band1=0
VCO_freq_O1
VCO_IB2=0
automatic
Comments
RF frequency 290-325 MHz
RF frequency 430-490 MHz
RF frequency 860-980 MHz
D6
Freq_Band0=1
VCO_freq_O0
VCO_IB1=0
settings,
bit
D5
is
set.
VCO_freq2=0
VCO_IB0=0
is
D4
22
Data
low VCO_freq setting creating a too low varactor
voltage. If the VCO_Fr_Auto bit is set, then the
transmitter will, if the varactor voltage is out of range,
change the programmed VCO_freq setting until the
voltage is within the range. A new setting will remain
active as long as power is on, VCO_Fr_Auto is set
and the programmed VCO_freq[2:0] bits are not
altered. The tuned VCO_freq setting of the
automatic tune circuit can be read out in the interrupt
register, VCO_Freq_O[2:0]. If both VCO_Fr_Chk
and VCO_Fr_Auto are set, each step is done by the
automatic tuning circuit that will be flagged with a
VC_LO or VC_HI interrupt. The limits of varactor
voltage used by this control circuit are between
350mV and 350mV below AVDD. The check is
performed
PA_LDc_en=1, the control will also be executed for
each programming creating an internal load pulse
(load_en=1) while staying in TX mode. This means
that when changing frequency, the MICRF405 will
check that the VCO_Freq[2:0] settings are correct
for the new frequency. Refer to Table 13 and Table
14 for further details.
The MICRF405 must be programmed with the
recommended settings for FreqBand and VCOfreq,
as given in Table 15, even if the VCO_Fr_Chk and
VCO_Fr_Auto are enabled. This is needed to give
the VCO the correct starting values.
The VCO can be bypassed by applying a differential
local oscillator (LO) signal to the device on pin
CPOUT and VARIN. A resistor of 18k Ω to ground
and a series capacitor of 47pF are needed on both
pins for proper biasing. The bit VCO_by must be set
to 1.
VCO_freq1=1
VCO_by=0
D3
when
VCO_freq0=1
OUTS2=0
VC_HI
D2
entering
Modulation1=1
OUTS1=0
VC_LO
D1
TX
Modulation0=0
mode.
(408) 955-1690
LOW_BATT
M9999-041906
OUTS0=0
D0
If

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