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| 型号： | MICRF007BM |
| 厂商： | Micrel Inc |
| 文件页数： | 9/13页 |
| 文件大小： | 0K |
| 描述： | IC RECEIVER UHF LOW POWER 8SOIC |
| 标准包装： | 95 |
| 频率： | 300MHz ~ 440MHz |
| 灵敏度： | -96dBm |
| 数据传输率 - 最大： | 2.1 kbps |
| 调制或协议： | ASK，OOK |
| 应用： | RKE |
| 电流 - 接收： | 3mA |
| 数据接口： | PCB，表面贴装 |
| 天线连接器： | PCB，表面贴装 |
| 特点： | 自动调谐 |
| 电源电压： | 4.75 V ~ 5.5 V |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 供应商设备封装： | 8-SOIC |
| 包装： | 管件 |
50
MICRF007
Inductor values may be different from Table 4, depending
on PCB material, PCB thickness, ground con?guration, 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 SHUT is high, the
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
100k ? resistor to ground
Power Supply Bypass Capacitors
Power supply bypass capacitor(s) connected to V DD should
have the shortest possible lead lengths to V SS .
Increasing Selectivity with Optional Band-Pass Filter
Micrel
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
Active
Load
3pF
6k
Active
Bias
Figure 4. 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 SS .
C TH Pin
VDD
For applications located in high ambient noise environments,
a ?xed value band-pass network may be connected between
the ANT pin and V SS to provide additional receiver selectivity
and input overload protection. A minimum input con?gura-
tion is included in Figure 10. It provides some ?ltering and
necessary overload protection.
Compa-
rator
1.5A
67.5A
CAGC
Figure 5. C TH Pin
pin is driven from a P-Channel MOSFET source-follower
with approximately 10μA of bias. Transmission gates TG1
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:
1. Analog squelch to raise the demodulator threshold
2. Digital squelch to disable the output when data is not
present
3. Output ?lter to ?lter the (high frequency) noise glitches
on the data output pin.
The simplest solution is to add analog squelch by introduc-
ing a small offset, or squelch voltage, on the C TH pin so that
noise does not trigger the internal comparator. Usually 20mV
to 30mV is suf?cient, and may be achieved by connecting
a several-meg-ohm resistor from the C TH pin to either V SS
or V DD , depending on the desired offset polarity. Since
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 suf?cient to quiet the output. Typical
squelch resistor values range from 10MΩ to 6.8MΩ for low
to high squelch strength.
Timout
15A 675A
Figure 5 illustrates the C TH -pin interface circuit. The C TH
VSS
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 TH pin is
approximately 1.6V
C AGC Pin
Figure 6 illustrates the C AGC pin interface circuit. The AGC
control voltage is developed as an integrated current into a
capacitor C AGC . The attack current is nominally 1.5μA, while
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 AGC decreases. By simply adding a
capacitor to C AGC pin, the attack/decay time constant ratio
is ?xed at 10:1. Modi?cation of the attack/decay ratio is pos-
sible by adding resistance from the C AGC pin to either VDD
or VSS, as desired.
Both the push and pull current sources are disabled during
shutdown, which maintains the voltage across C AGC , and
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 AGC while in shutdown.
February 17, 2005
9
M9999-021705
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相关代理商/技术参数 |
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| MICRF007BM TR | 功能描述:IC RECEIVER UHF 300MHZ 8-SOIC RoHS:否 类别:RF/IF 和 RFID >> RF 接收器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS 产品变化通告:Product Discontinuation 09/Jan/2012 标准包装:50 系列:* 频率:850MHz ~ 2.175GHz 灵敏度:- 数据传输率 - 最大:- 调制或协议:- 应用:* 电流 - 接收:* 数据接口:PCB，表面贴装 存储容量:- 天线连接器:PCB，表面贴装 特点:- 电源电压:4.75 V ~ 5.25 V 工作温度:0°C ~ 85°C 封装/外壳:40-WFQFN 裸露焊盘 供应商设备封装:40-TQFN-EP（6x6） 包装:托盘 |
| MICRF007YM | 功能描述:射频接收器 300-440MHz Receiver, 1.2kbps, 1.7mA With Shutdown( Lead Free) RoHS:否 制造商:Skyworks Solutions, Inc. 类型:GPS Receiver 封装 / 箱体:QFN-24 工作频率:4.092 MHz 工作电源电压:3.3 V 封装:Reel |
| MICRF007YM TR | 功能描述:射频接收器 300-440MHz Receiver, 1.2kbps, 1.7mA With Shutdown( Lead Free) RoHS:否 制造商:Skyworks Solutions, Inc. 类型:GPS Receiver 封装 / 箱体:QFN-24 工作频率:4.092 MHz 工作电源电压:3.3 V 封装:Reel |
| MICRF008 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:QwikRadio Sweep-Mode Receiver |
| MICRF008_11 | 制造商:MICREL 制造商全称:Micrel Semiconductor 功能描述:QwikRadio Sweep-Mode Receiver |
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