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| 型号： | MAX1471ATJ+ |
| 厂商： | Maxim Integrated |
| 文件页数： | 14/26页 |
| 文件大小： | 0K |
| 描述： | IC RCVR ASK/FSK LP 32-TQFN |
| 其它有关文件： | Automotive Product Guide |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 60 |
| 频率： | 315MHz，434MHz |
| 灵敏度： | -114dBm |
| 调制或协议： | ASK，FSK |
| 应用： | ISM，车库门开启器，RKE |
| 电流 - 接收： | 7mA |
| 数据接口： | PCB，表面贴装 |
| 天线连接器： | PCB，表面贴装 |
| 电源电压： | 3.3V，5V |
| 工作温度： | -40°C ~ 125°C |
| 封装/外壳： | 32-WFQFN 裸露焊盘 |
| 供应商设备封装： | 32-TQFN-EP（5x5） |
| 包装： | 管件 |
315MHz/434MHz Low-Power, 3V/5V
ASK/FSK Superheterodyne Receiver
Table 2. Coefficients to Calculate CF1
and CF2
Peak Detectors
The maximum peak detectors (PDMAXA for ASK,
PDMAXF for FSK) and minimum peak detectors (PDMI-
FILTER TYPE
Butterworth
(Q = 0.707)
Bessel
(Q = 0.577)
a
1.414
1.3617
b
1.000
0.618
NA for ASK, PDMINF for FSK), in conjunction with resis-
tors and capacitors shown in Figure 5, create DC
output voltages proportional to the high and low peak
values of the filtered ASK or FSK demodulated signals.
The resistors provide a path for the capacitors to dis-
charge, allowing the peak detectors to dynamically fol-
low peak changes of the data-filter output voltages.
The maximum and minimum peak detectors can be
used together to form a data-slicer threshold voltage at
MAX1471
100k ?
RSSI OR
FSK DEMOD
100k ?
a midvalue between the maximum and minimum volt-
age levels of the data stream (see the Data Slicers sec-
tion and Figure 5). The RC time constant of the peak-
detector combining network should be set to at least 5
times the data period.
If there is an event that causes a significant change in
the magnitude of the baseband signal, such as an AGC
DSA+
DSF+
C F2
OPA+
OPF+
C F1
DFA
DFF
gain switch or a power-up transient, the peak detectors
may “catch” a false level. If a false peak is detected,
the slicing level is incorrect. The MAX1471 has a fea-
ture called peak-detector track enable (TRK_EN),
where the peak-detector outputs can be reset (see
Figure 6). If TRK_EN is set (logic 1), both the maximum
Figure 3. Sallen-Key Lowpass Data Filter
MAX1471
DATA
SLICER
and minimum peak detectors follow the input signal.
When TRK_EN is cleared (logic 0), the peak detectors
revert to their normal operating mode. The TRK_EN
function is automatically enabled for a short time and
then disabled whenever the IC recovers from the sleep
portion of DRX mode, or when an AGC gain switch
occurs. Since the peak detectors exhibit a fast
attack/slow decay response, this feature allows for an
extremely fast startup or AGC recovery. See Figure 7
for an illustration of a fast-recovery sequence. In addi-
ADATA
FDATA
C
DSA-
DSF-
R
DSA+
DSF+
tion to the automatic control of this function, the
TRK_EN bits can be controlled through the serial inter-
face (see the Serial Control Interface section).
If the peak detectors are not used, make sure that the
FSKPD_EN and ASKPD_EN bits in Register 0x0 are
maintained at the default setting of logic 0 and short
Figure 4. Generating Data-Slicer Threshold Using a Lowpass
Filter
coding, which has an equal number of zeros and ones,
is used.
Figure 5 shows a configuration that uses the positive and
negative peak detectors to generate the threshold. This
configuration sets the threshold to the midpoint between
a high output and a low output of the data filter.
each of the four PD pins directly to ground or through a
capacitor whose value is approximately 1000pF. If a
peak detector pin is left open, the FDATA and ADATA
signals can potentially couple back into the DSA+ or
the DSA- lines (depending on circuit design and lay-
out), causing an oscillation at the output of the data
slicer comparator. The PDMINA peak detector is partic-
ularly vulnerable to this coupling because its pin (31) is
next to the ADATA pin (30).
14
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1471ATJ/V+ | 功能描述:射频接收器 315MHz/434MHz Low-Power 3V/5V ASK/FSK Superheterodyne Receiver 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 |
| MAX1471ATJ/V+T | 功能描述:射频接收器 315MHz/434MHz Low-Power 3V/5V ASK/FSK Superheterodyne Receiver 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 |
| MAX1471ATJ+ | 功能描述:射频接收器 315MHz/434MHz Superheterodyne Rcvr 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 |
| MAX1471ATJ+T | 功能描述:射频接收器 315MHz/434MHz Superheterodyne Rcvr 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 |
| MAX1471ATJ-C3N | 功能描述:射频接收器 315MHz/434MHz Superheterodyne Rcvr 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 |
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