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.


  • 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 Ld surface mount packaging
  • Reduced footprint micro leadframe packaging
  • Dielectric isolated (DI) high voltage design
  • QFN package:
    • 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)


  • Voice over Internet Protocol (VoIP)
  • Cable modems
  • Voice over DSL (VoDSL)
  • Short loop access platforms
  • Remote subscriber units
  • Terminal adapters

tuneProduct Options

Part Number Part Status Pkg. Type Carrier Type MOQ Buy Sample
Active PLCC Tube 37
Active PLCC Reel 750
Last Time Buy PLCC Tube 37
Last Time Buy PLCC Reel 750
Last Time Buy PLCC Tube 37
Last Time Buy PLCC Reel 750
Last Time Buy PLCC Tube 37
Last Time Buy PLCC Tube 37


Title language Type Format File Size Date
Datasheets & Errata
star HC55185 Datasheet Datasheet PDF 1007 KB
User Guides & Manuals
AN1003: Operation of the HC55185 Ringing SLIC & IDT821054 Evaluation Module Manual - Development Tools PDF 1.22 MB
Application Notes & White Papers
AN9998: HC55185 and the IDT821054/64 Programmable Quad PCM CODEC Application Note PDF 484 KB
AN9640: Glossary of Communication Terms Application Note PDF 1.24 MB
AN9947: HC55185 and the IDT821068 Programmable Octal PCM CODEC Application Note PDF 1.07 MB
AN9991: HC55185 and the IDT821068 Programmable Octal PCM CODEC Application Note PDF 511 KB
AN9933: HC55185 and the Texas Instruments TCM38C17 Quad Combo Application Note PDF 470 KB
AN9922: Thermal Characterization and Board Level Modeling of the RSLIC18 in the Micro Leadframe Package Application Note PDF 1.90 MB
AN9824: SPICE Model Tutorial of the RSLIC18 AC Loop Application Note PDF 569 KB
AN9842: Implementing Tip and Ring Protection Circuitry For the HC5518X Ringing SLIC Family Application Note PDF 367 KB
PLC21035 - End of Life Notice Product Life Cycle Notice PDF 1.17 MB
PLC18018 - General Q3 Product Life Cycle Notice Product Life Cycle Notice PDF 388 KB
PA14042 - Minimum Line Quantity Change Product Advisory PDF 363 KB
PCN13060 - Test Site Change for the Listed Intersil Products Product Change Notice PDF 223 KB
PCN12087 - PLCC w/ Gold Bond Wire from ANST to ATP as Alternate Assembly Site Product Change Notice PDF 86 KB
TB384: Evaluating the HC55185 with the HC5518XEVAL Evaluation Platform Other PDF 201 KB

memoryBoards & Kits

Part Number Title Type Company
ISL5585EVAL4 3.3V Ringing SLIC Family for Voice Over Broadband (VOB) Evaluation Board Evaluation Renesas