MICRF007YM Micrel Inc, MICRF007YM Datasheet - Page 9

• Manufacturer Part Number: MICRF007YM
• Description: IC RECEIVER UHF LOW POWER 8SOIC
• Manufacturer: Micrel Inc

Specifications of MICRF007YM

• Frequency: 300MHz ~ 440MHz
• Sensitivity: -96dBm
• Data Rate - Maximum: 2.1 kbps
• Modulation Or Protocol: ASK, OOK
• Applications: RKE
• Current - Receiving: 3mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Features: Automatic Tuning
• Voltage - Supply: 4.75 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Receiving Current: 5.7mA
• Data Rate: 3.2Kbps
• Modulation Type: ASK, OOK
• Frequency Range: 300MHz To 440MHz
• Sensitivity Dbm: -99dBm
• Rf Ic Case Style: SOIC
• No. Of Pins: 8
• Operating Band Frequency: 300 to 440MHz
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Product Depth (mm): 3.94mm
• Product Height (mm): 1.48mm
• Operating Supply Voltage (min): 4.75V
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.5V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Lead Free Status / Rohs Status: Compliant
• Other names: 576-1334

Inductor values may be different from Table 4, depending
on PCB material, PCB thickness, ground configuration, and
how long the traces are in the layout. Values shown were
charac-terized for a 0.031 inch thickness, FR4 board, solid
ground plane on bottom layer, and very short traces. Murata
and Coilcraft wire-wound 0603 or 0805 surface mount induc-
tors were tested, however, any wire-wound inductor with high
SRF (self-resonance frequency) should do the job.
Shutdown Function
Duty-cycled operation of the MICRF007 (often referred to
as polling) is achieved by turning the MICRF007 on and off
via the SHUT pin. The shutdown function is controlled by a
logic state applied to the SHUT pin. When V
device goes into low-power standby mode. This pin is pulled
high internally, it must be externally pulled low to enable the
receiver. It is recommended to connect this pin through a
100kΩ resistor to ground
Power Supply Bypass Capacitors
Power supply bypass capacitor(s) connected to V
have the shortest possible lead lengths to V
Increasing Selectivity with Optional Band-Pass Filter
For applications located in high ambient noise environments,
a fixed value band-pass network may be connected between
the ANT pin and V
and input overload protection. A minimum input configura-
tion is included in Figure 10. It provides some filtering and
necessary overload protection.
Data Squelching
During quiet periods (no signal), the data output (DO pin)
transitions randomly with noise. Most decoders can discrimi-
nate between this random noise and actual data. But for some
system, it does present a problem. There are three possible
approaches to reduce this output noise:
The simplest solution is to add analog squelch by introduc-
ing a small offset, or squelch voltage, on the C
noise does not trigger the internal comparator. Usually 20mV
to 30mV is sufficient, and may be achieved by connecting
a several-meg-ohm resistor from the C
or V
MICRF007’s receiver AGC noise at the internal comparator
input is always the same (set by the AGC), the squelch offset
requirement does not change as the local noise strength
changes from installation to installation. Introducing squelch
will reduce sensitivity and also reduce range. Only introduce
an amount of offset sufficient to quiet the output. Typical
squelch resistor values range from 10MΩ to 6.8MΩ for low
to high squelch strength.
February 17, 2005
MICRF007
1. Analog squelch to raise the demodulator threshold
2. Digital squelch to disable the output when data is not
3. Output filter to filter the (high frequency) noise glitches
DD
present
on the data output pin.
, depending on the desired offset polarity. Since
SS
to provide additional receiver selectivity
TH
pin to either V
SHUT
SS
TH
.
is high, the
pin so that
DD
should
SS
9
I/O Pin Interface Circuitry
Interface circuitry for the various I/O pins of the MICRF007
are diagrammed in Figures 4 through 9. The ESD protection
diodes at all input and output pins are not shown.
ANT Pin
The ANT pin is internally AC-coupled via a 3pF capacitor to
an RF N-Channel MOSFET, as shown in Figure 4. Im-ped-
ance on this pin to VSS is quite high at low frequencies, and
decreases as frequency increases. In the UHF fre-quency
range, the device input can be modeled as 6.3k. in parallel
with 2pF (pin capacitance) to V
C
Figure 5 illustrates the C
pin is driven from a P-Channel MOSFET source-follower
with approximately 10µA of bias. Transmission gates TG1
and TG2 isolate the 6.9pF capacitor. Internal control signals
PHI1/PHI2 are related in a manner such that the impedance
across the transmission gates looks like a “resistance” of
approximately 110kΩ. The DC potential at the C
approximately 1.6V
C
Figure 6 illustrates the C
control voltage is developed as an integrated current into a
capacitor C
the decay current is a 10 times scaling of this, approximately
15µA. Signal gain of the RF/IF strip inside the IC diminishes
as the voltage on C
capacitor to C
is fixed at 10:1. Modification of the attack/decay ratio is pos-
sible by adding resistance from the C
or VSS, as desired.
Both the push and pull current sources are disabled during
shutdown, which maintains the voltage across C
improves recovery time in duty-cycled applications. To further
improve duty-cycle recovery, both push and pull currents are
increased by 45 times for approximately 10ms after release
of the SHUT pin. This allows rapid recovery of any voltage
drop on C
TH
AGC
Pin
Pin
Timout
AGC
Compa-
rator
AGC
AGC
while in shutdown.
. The attack current is nominally 1.5µA, while
pin, the attack/decay time constant ratio
1.5A
15A
Figure 4. ANT Pin
Figure 5. C
Active
AGC
50
Bias
VDD
VSS
AGC
3pF
TH
decreases. By simply adding a
-pin interface circuit. The C
pin interface circuit. The AGC
SS
67.5A
675A
6k
TH
Active
.
Load
Pin
AGC
CAGC
pin to either VDD
M9999-021705
AGC
TH
Micrel
pin is
, and
TH