MICRF213AYQS Micrel Inc, MICRF213AYQS Datasheet - Page 8

• Manufacturer Part Number: MICRF213AYQS
• Description: IC RX 3.3V 300-350 MHZ 16-QSOP
• Manufacturer: Micrel Inc

Specifications of MICRF213AYQS

• Operating Temperature: -40°C ~ 105°C
• Frequency: 300MHz ~ 350MHz
• Sensitivity: -110dBm
• Data Rate - Maximum: 7.2 kbps
• Modulation Or Protocol: AM, OOK
• Applications: ISM, Garage Door Openers, RKE
• Current - Receiving: 3.9mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Voltage - Supply: 3 V ~ 3.6 V
• Package / Case: 16-QSOP
• Receiving Current: 3.9mA
• Data Rate: 7.2Kbps
• Modulation Type: ASK, OOK
• Frequency Range: 300MHz To 350MHz
• Rf Ic Case Style: QSOP
• No. Of Pins: 16
• Supply Voltage Range: 3V To 3.6V
• Sensitivity Dbm: -110dBm
• Rohs Compliant: Yes
• Operating Temperature (min): -40C
• Operating Temperature (max): 105C
• Operating Temperature Classification: Industrial
• Operating Supply Voltage (typ): 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: 576-1649-5

Application Information
The MICRF213 can be fully tested by using one of the
many evaluation boards designed by Micrel and
intended for use with this device. As an entry level,
the QR213HE1 (reference Figure 3) offers a good
start for most applications. It has a helical PCB
antenna with its matching network, a band-pass-filter
front-end as a pre-selector filter, matching network
and the minimum components required to make the
device work. The minimum components are a crystal,
Cagc, and Cth capacitors. By removing the matching
network of the helical PCB antenna (C9 and L3), a
whip antenna (ANT2) or a RF connector (J2) can be
used instead. Figure 3 shows the entire schematic for
315MHz. Other frequencies can be used and the
values needed are listed in the tables below.
Capacitor C9 and inductor L3 are the passive
elements for the helical PCB matching network. It is
recommended that a tight tolerance be used for these
devices; such as 2% for the inductor and 0.1pF for the
capacitor. PCB variations may require different values
and optimization. Table 2 shows the matching
elements for the device frequency range. For
additional information, reference the: Small PCB
Antennas for Micrel RF Products application note.
To use another antenna, such as the whip kind, remove
C9 and place the whip antenna in the hole provided in
the PCB. Also, a RF signal can be injected there.
Table 2. Matching Values for the Helical PCB Antenna
Micrel, Inc.
May 2007
J2
(np)SMA
Freq (MHz)
303.825
315
345
ANT2
L1
39nH 5%
C8
6.8pF
C9 (pF)
1.8pF
C9
C3
1.2
1.2
1.2
ANT1
Helical PCB Antenna Pattern
L2
68nH 5%
+3.3V
Figure 3. QR213HE1 Application Example, 315MHz
75nH 2%
L3
L3 (nH)
C5
0.1µF
82
75
62
JP3
open
JP1
short
8
R3
L1 and C8 form the pass-band-filter front-end. Its
purpose is to attenuate undesired outside band noise
which reduces the receiver performance. It is
calculated
f = 1/(2*PI*(SQRT(L1*C8)). Table 3 shows the most
used frequency values.
There is no need for the band-pass-filter front-end for
applications where it is proven the outside band noise
does not cause a problem. The MICRF213 has image
reject mixers which improve significantly the selectivity
and rejection of outside band noise.
Capacitor C3 and inductor L2 form the L-shape
matching network. The capacitor provides additional
attenuation for low frequency outside band noise and
the inductor provides additional ESD protection for the
antenna pin. Two ways can be used to find these
values, which are matched close to 50Ω. One method
is done by calculating the values using the equations
below and another by using a Smith chart. The latter
is made easier by using software that plots the values
of the components C8 and L1, like WinSmith by Noble
Publishing.
To calculate the matching values, one needs to know
the input impedance of the device. Table 4 shows the
input impedance of the MICRF213 and the suggested
matching values used for the most frequencies.
1
2
3
4
5
6
7
8
RO1
GNDRF
ANT
GNDRF
VDD
SQ
SEL0
SHDN
Freq (MHz)
303.825
315
345
U1 MICRFAYQS
Table 3. Band-Pass-Filter Front-End Values
+3.3V
RSSI
GND
NC
SH
D0
Y1
9.81563MHz
1
2
3
4
5
6
by
CAGC
SEL1
RSSI
GND
RO2
CTH
NC
DO
the
16
15
14
13
12
11
10
9
RSSI
DO
SH
+3.3V
RSSI
DO
parallel
C8 (pF)
6.8
6.8
5.6
JR2
short
resonance
C6
0.47µF
M9999-052307-A
[phone]
L1 (nH)
C4
4.7µF
39
39
39
MICRF213
equation
+3.3V
R1
(np)
R2
(np)