滤波器:Atmel ATA572x ASK/FSK接收器汽车应用方案

　　Atmel公司的ATA5723、ATA5724 和 ATA5728是超高频 (UHF) ASK/FSK 接收器集成电路 (IC),为广泛的汽车射频设备提供了性能组合. 这三款新器件在高度整合、出色性能和全球频率覆盖之间提供了最佳平衡。

这三款新的集成电路与引脚兼容，这意味着它们在不更改板设计的条件下便可用于所有标准的汽车频率范围：313-317 MHz (ATA5723)、432-436 MHz (ATA5724) 以及 868-870 MHz (ATA5728)。这些器件是使用 Atmel 的射频 BiCMOS 工艺生产的。这些器件采用的是一种体积很小的 SSO20 封装，非常适合遥控车门开关 (RKE) 和汽车轮胎压力监测系统 (TPMS) 应用。

ATA5723、ATA5724 和 ATA5728 支持专用的曼彻斯特与二相编码信号。此外，它们还提供对数 RSSI 输出，使客户能够在较低的场强下实现较高的分辨率。这些集成电路出色的接收选择性是通过整合的镜频抑制混频器来实现的。

由于整合的 IF 滤波器、低相位噪声压控振荡器 (VCO)、锁相环 (PLL) 以及环路滤波器，该混频器具有 30 dB 抑制性、-113 dBm 灵敏性以及改善的选择性。

       新款接收器集成电路只需很少的外部器件，同时无需外部滤波器，这使它们更具成本效益。10个无源元件、1个晶体以及1个射频天线是制作一个接收器板应用所必备的。此外，由于集成电路具有较大的振动空间，因此设计者能够选择成本极低的晶体。

       The ATA5723/ATA5724/ATA5728 is a multi-chip PLL receiver device supplied in an SSO20
package. It has been specially developed for the demands of RF low-cost data transmission systems with data rates from 1 kBit/s to 10 kBbit/s in Manchester or Bi-phase code. Its main
applications are in the areas of keyless entry systems, tire pressure monitoring systems, telemetering, and security technology systems. It can be used in the frequency receiving range of f0 = 312.5 MHz to 317.5 MHz, f0 = 431.5 MHz to 436.5 MHz or f0 = 868 MHz to 870 MHz for
ASK or FSK data transmission. All the statements made below refer to 315 MHz, 433 MHz and
868.3 MHz applications.

       主要特性:
Frequency Receiving Range of (3 Versions)
– f0 = 312.5 MHz to 317.5 MHz or
– f0 = 431.5 MHz to 436.5 MHz or
– f0 = 868 MHz to 870 MHz
30 dB Image Rejection
Receiving Bandwidth
– BIF = 300 kHz for 315 MHz/433 MHz Version
– BIF = 600 kHz for 868 MHz Version
Fully Integrated LC-VCO and PLL Loop Filter
Very High Sensitivity with Power Matched LNA
– ATA5723/ATA5724:
–107 dBm, FSK, BR_0 (1.0 kbit/s to 1.8 kBit/s), Manchester, BER 10E-3
–113 dBm, ASK, BR_0 (1.0 kbit/s to 1.8 kBit/s), Manchester, BER 10E-3
– ATA5728:
–105 dBm, FSK, BR_0 (1.0 kbit/s to 1.8 kBit/s), Manchester, BER 10E-3
–111 dBm, ASK, BR_0 (1.0 kbit/s to 1.8 kBit/s), Manchester, BER 10E-3
High System IIP3
– –18 dBm at 868 MHz
– –23 dBm at 433 MHz
– –24 dBm at 315 MHz
System 1-dB Compression Point
– –27.7 dBm at 868 MHz
– –32.7 dBm at 433 MHz
– –33.7 dBm at 315 MHz
High Large-signal Capability at GSM Band (Blocking –33 dBm at +10 MHz,
IIP3 = –24 dBm at +20 MHz)
Logarithmic RSSI Output
XTO Start-up with Negative Resistor of 1.5 k
5V to 20V Automotive Compatible Data Interface
Data Clock Available for Manchester and Bi-phase-coded Signals
Programmable Digital Noise Suppression
Low Power Consumption Due to Configurable Polling
Temperature Range –40°C to +105°C
ESD Protection 2 kV HBM, All Pins
Communication to Microcontroller Possible using a Single Bi-directional Data Line
Low-cost Solution Due to High Integration Level with Minimum External Circuitry
Requirements

       优势:
Low BOM List Due to High Integration
Use of Low-cost 13 MHz Crystal
Lowest Average Current Consumption for Application Due to Self Polling Feature
Reuse of ATA5743 Software
World-wide Coverage with One PCB Due to 3 Versions are Pin Compatible

       系统方框图:

ATA572x方框图:

ATA572x应用电路图: