原标题：Intersil HC55185 VoIP Ringing SLIC方案

　　ntersil 公司的HC55185是网上电话( VoIP)铃音用户接口电路( Ringing SLIC),支持中短回路长度的模拟POTS的无线和有线应用. RSLIC-VoIP系列工作到100V电压,用户线长度可扩展到500欧姆(即5000英尺)或更长.其它特性还包括低功耗,振铃信号采用正弦或梯形波,自动检测机制等. VoIP Ringing SLIC系列主要用在网络电话(VoIP),线缆调制解调器,DSL语音,短回路接入平台,遥控用户线单元以及终端适配器.本文介绍了HC55185的主要特性, 方框图, 基本应用电路图和所用元件列表,以及HC5518XEVAL 评估板的方框图,电路图和评估板元件列表.

　　The RSLIC-VoIP family of ringing subscriber line interface circuits (RSLIC) supports analog Plain Old Telephone Service (POTS) in short and medium loop length, wireless and wireline applications. Ideally suited for remote subscriber units, this family of products offers flexibility to designers with high ringing voltage and low power consumption system

　　requirements.

　　The RSLIC-VoIP family operates to 100V which translates directly to the amount of ringing voltage supplied to the end subscriber. With the high operating voltage, subscriber loop

　　lengths can be extended to 500Ω (i.e., 5,000 feet) and beyond.

　　Other key features across the product family include: low power consumption, ringing using sinusoidal or trapezoidal waveforms, robust auto-detection mechanisms for when

　　subscribers go on or off hook, and minimal external discrete application components. Integrated test access features are also offered on selected products to support loopback

　　testing as well as line measurement tests.

　　There are five product offerings of the HC55185 with each version providing voltage grades of high battery voltage and longitudinal balance. The voltage feed amplifier design uses low fixed loop gains to achieve high analog performance with low susceptibility to system induced noise.

　　HC55185主要特性:

　　Onboard Ringing Generation

　　Compatible with Existing HC5518x Devices

　　Low Standby Power Consumption (75V, 65mW)

　　Reduced Idle Channel Noise

　　Programmable Transient Current Limit

　　Improved Off Hook Software Interface

　　Integrated MTU DC Characteristics

　　Low External Component Count

　　Silent Polarity Reversal

　　Pulse Metering and On Hook Transmission

　　Tip Open Ground Start Operation

　　Balanced and Unbalanced Ringing

　　Thermal Shutdown with Alarm Indicator

　　28 Lead Surface Mount Packaging

　　Reduced Footprint Micro Leadframe Packaging

　　Dielectric Isolated (DI) High Voltage Design

　　QFN Package Option

　　Compliant to JEDEC PUB95 MO-220 QFN - Quad Flat No Leads - Product Outline

　　Near Chip Scale Package Footprint; Improves PCB efficiency and has a thinner profile

　　Pb-free plus anneal available (RoHS compliant)

　　HC55185应用:

　　Voice Over Internet Protocol (VoIP)

　　Cable Modems

　　Voice Over DSL (VoDSL)

　　Short Loop Access Platforms

　　Remote Subscriber Units

　　Terminal Adapters

　　图1.HC55185方框图

　　图2.HC55185基本应用电路

　　基本应用电路所用元件列表:

　　HC5518XEVAL 评估板

　　The HC5518XEVAL evaluation board provides a complete evaluation system for the HC55185 family of ringing SLICs. The evaluation board design consists of the HC55185 device application circuit, a single +5V CODEC for line circuit evaluations and on board logic for stand alone operation. The evaluation boards have been designed to support back to back operation, providing further insight to the complete signal path and solution.

　　The transient behavior of the SLIC in response to mode changes has been significantly improved with the HC55185 design. The benefit to the application is reduction or more

　　likely elimination of DET glitches when off hook events occur. In addition to internal circuit modifications, the change of the CFB value contributes to this functional improvement.

　　Please reference the HC55185 data sheet for detailed information regarding this feature.

　　Voltage ratings for external components have been selected based on 100V device operation, therefore compatibility to lower voltage versions is guaranteed.

　　图3.HC5518XEVAL 评估板方框图

　　Evaluation Board Schematic

　　图4.HC5518XEVAL评估板电路图

　　HC5518XEVAL评估板元件列表: