SI3215-KT - 90 VPK Programmable SLIC/Codec | Silicon Labs
MPN: SI3215-KT ✗ End of LifeSI3215-KT Overview
A SLIC, or subscriber-line interface circuit, is the analog front end between a telephone line and digital voice-processing circuitry. A COC, or codec, converts that analog voice signal into a digital PCM stream. The SI3215-KT combines these functions in a programmable CMOS IC, reducing external circuitry while allowing line parameters and signaling behavior to be configured through the device software.
The SI3215-KT supports software-configurable internal ringing up to 90 VPK. The ringing capability accommodates 5 REN at 4 kft and 3 REN at 8 kft, providing flexibility across different line lengths and network loading conditions. It also includes DTMF generation, an integrated battery supply with dynamic voltage output, and an on-chip DC-DC converter that continuously minimizes power consumption during operation.
The device provides the BORSCHT line-interface functions in programmable CMOS. Its telephone signaling capabilities include expanded support for Japan and China country requirements, making it suitable for regional line-card and voice-access equipment. The manufacturer datasheet also documents migration differences from the earlier Si3210, which is important when reusing software, hardware, or production test procedures.
Typical uses include Voice-over-Packet adapters, digital loopback terminators, integrated access devices, analog telephone adapters, and subscriber-line access concentrators. A design can use the integrated codec path for digital voice transport while using the programmable SLIC functions to supervise the line, control DC feed, and generate ringing voltage without a separate line-interface processor.
Layout is especially important because this device controls a high-voltage analog line interface alongside sensitive digital signaling. Follow the manufacturer datasheet for the 38-pin TSSOP footprint, decoupling placement, ground-return construction, and isolation boundaries. Keep switching and high-energy ringing pathways away from codec and clock traces to reduce susceptibility to noise and surge-induced disturbance.
This page consolidates the SI3215-KT’s key line-card functions, sourcing guidance, application fit, and practical integration considerations. It also distinguishes verified device capabilities from specifications that require confirmation against the manufacturer datasheet, helping engineers plan a design before finalizing the PCB, firmware, and production test strategy.
Drop-in alternatives for SI3215-KT — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
SI3215-K-FT
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
SI3215-G-FT
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
SI3215-E-FT
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
SI3215-B-FT
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
SI3215-KT Specifications
| Product Type | Programmable CMOS SLIC/codec |
| Maximum Internal Ringing Voltage | 90 VPK |
| Maximum Ringing Load | 5 REN at 4 kft |
| Reduced Ringing Load | 3 REN at 8 kft |
| Ringing Configuration | Software-configurable |
| Line Interface Functions | BORSCHT functions |
| Tone Generation | DTMF generation |
| Battery Supply | Integrated battery supply with dynamic voltage output |
| Power Conversion | On-chip DC-DC converter |
| Regional Signaling Support | Expanded support for Japan and China country requirements |
| Target Package | 38-pin TSSOP |
| Available Device Packages | 38-pin QFN and 38-pin TSSOP |
| Companion Line Interface Package | Thermally enhanced 16-pin SOIC for Si3201 |
| Mounting Type | Surface mount |
| Lifecycle Status | Obsolete |
SI3215-KT thermally enhanced 16-pin soic for si3201 Pin Configuration Guide
Pin configuration for SI3215-KT (thermally enhanced 16-pin soic for si3201 package). Pin numbering, functions, and connection diagrams are defined in the manufacturer datasheet. Refer to it for the exact footprint and soldering guidelines.
No detailed pinout data available for SI3215-KT.
Refer to the datasheet for full pin configuration.
Typical Applications
SI3215-KT is suitable for 6 applications: Voice-over-Packet Adapter, Analog Telephone Adapter, Digital Loopback Terminator, Subscriber-Line Access Concentrator, Embedded Voice Communication System, Telephone-Line Test Equipment.
Voice-over-Packet Adapter
The SI3215-KT fits a Voice-over-Packet adapter because it combines a subscriber-line interface, voice codec, DTMF generation, and programmable ringing in one device. Its internal ringing generator supports up to 90 VPK, with a stated capability of 5 REN at 4 kft and 3 REN at 8 kft, allowing one line-interface design to cover different loop lengths. The codec path connects analog voice to a digital packet-processing subsystem, while software control manages line supervision and tone behavior. This integration reduces the number of separate line-interface functions, but the finished adapter still needs proper surge protection, isolation as required by its target network, and country-specific line qualification.
Recommended
Analog Telephone Adapter
The SI3215-KT is appropriate for an analog telephone adapter requiring integrated line supervision and codec conversion. Its BORSCHT functionality addresses the principal hook-state, DC-feed, and line-monitoring functions, while the integrated battery supply reduces the external discrete circuitry normally required for a telephone line. Software-configurable ringing up to 90 VPK allows the same platform to address different line loads, including 5 REN at 4 kft and 3 REN at 8 kft. Designers should still account for metallic-line isolation, overvoltage protection, hook-state timing, and regional requirements because the SLIC/codec alone does not establish complete regulatory approval.
Recommended
Digital Loopback Terminator
A digital loopback terminator can use the SI3215-KT to provide the physical telephone-line interface in equipment where voice is transported digitally rather than converted to an analog audio jack. The integrated codec handles voice conversion, the programmable ringing section generates the line-side ring signal, and DTMF generation supports basic signaling functions. Up to 90 VPK internal ringing and the stated 5 REN at 4 kft or 3 REN at 8 kft capability are useful when one product must serve multiple loop-length conditions. For laboratory and production-test equipment, include controlled line termination and protection so that fault conditions cannot exceed the device or external network interfaces.
Recommended
Subscriber-Line Access Concentrator
The SI3215-KT can support a multi-channel subscriber-line access design where each line requires programmable supervision, ringing, and codec conversion. Software configuration is particularly valuable in concentrated equipment because line parameters can be adapted across subscriber environments instead of requiring separate fixed hardware for every condition. The device provides software-configurable ringing up to 90 VPK, DTMF generation, dynamic battery supply, and an on-chip DC-DC converter. In a multichannel implementation, isolate routing, maintain short return paths, and separate high-voltage ringing energy from digital clock and data lines. Thermal and EMC performance must be evaluated across the complete channel count rather than from one isolated SLIC circuit.
Recommended
Embedded Voice Communication System
The SI3215-KT is suitable for an embedded voice communication system that connects a physical telephone line to a processor-based media path. Its integrated codec eliminates a separate voice conversion stage, while the SLIC functions provide line supervision, DC feed, ringing, and DTMF generation in a programmable device. The 90 VPK internal ringing capability supports real subscriber-loop conditions, and the stated loading limits help determine channel count and loop-length assumptions. System designers should reserve firmware resources for calibration and country configuration, use the manufacturer reference circuit for decoupling, and confirm that the surrounding isolation and surge-protection architecture satisfies the intended telephone network.
Recommended
Telephone-Line Test Equipment
The SI3215-KT can form the line-side element of telephone-line test equipment because it combines programmable ringing, battery generation, supervision, and voice conversion. Test configurations can vary ringing conditions and line states in software, while the codec provides a repeatable digital voice path for loopback or impairment testing. Its 90 VPK internal ringing capability and 5 REN at 4 kft or 3 REN at 8 kft loading information are useful when defining a test range. Production fixtures should add current-limited line protection, clearly separated high-voltage and low-voltage areas, and automated shutdown controls to prevent a fixture fault from continuing to energize the telephone interface.
Recommended
Recommended Products Summary
Engineering reference data for SI3215-KT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SI3215-K-FT | SI3215-G-FT | SI3215-E-FT | SI3215-B-FT |
|---|---|---|---|---|---|
| Brand | Silicon Laboratories | Silicon Laboratories | Silicon Laboratories | Silicon Laboratories | Silicon Laboratories |
| Package | 38-pin TSSOP | 38-pin TSSOP | 38-pin TSSOP | 38-pin TSSOP | 38-pin TSSOP |
| Product Type | Programmable CMOS SLIC/codec | Programmable CMOS SLIC/codec | Programmable CMOS SLIC/codec | Programmable CMOS SLIC/codec | Programmable CMOS SLIC/codec |
| Maximum Internal Ringing Voltage | 90 VPK | 90 VPK | 90 VPK | 90 VPK | 90 VPK |
| Maximum Ringing Load | 5 REN at 4 kft | 5 REN at 4 kft | 5 REN at 4 kft | 5 REN at 4 kft | 5 REN at 4 kft |
| Reduced Ringing Load | 3 REN at 8 kft | 3 REN at 8 kft | 3 REN at 8 kft | 3 REN at 8 kft | 3 REN at 8 kft |
| Line Interface Functions | BORSCHT functions | BORSCHT functions | BORSCHT functions | BORSCHT functions | BORSCHT functions |
| Tone Generation | DTMF generation | DTMF generation | DTMF generation | DTMF generation | DTMF generation |
| Battery Supply | Integrated dynamic battery supply | Integrated dynamic battery supply | Integrated dynamic battery supply | Integrated dynamic battery supply | Integrated dynamic battery supply |
| Power Conversion | On-chip DC-DC converter | On-chip DC-DC converter | On-chip DC-DC converter | On-chip DC-DC converter | On-chip DC-DC converter |
Key Differentiators
- Integrated programmable ringing in the line-interface device (vs SI3215-K-FT)
- Consistent 38-pin TSSOP replacement path within the Si3215 family (vs SI3215-G-FT)
- Integrated battery supply and DC-DC conversion reduce external line-interface circuitry (vs SI3215-E-FT)
- Single-device combination of BORSCHT, codec, DTMF, ringing, and battery functions (vs SI3215-B-FT)
Design Notes
Place all input bypass, output-decoupling, and line-network components according to the manufacturer reference schematic. Keep the 38-pin TSSOP power and ground connections on short paths, use an uninterrupted ground plane where permitted, and route ringing and battery-current loops away from codec clock and data nets. Confirm every track and via against the package drawing because the TSSOP footprint must not be confused with the family's 38-pin QFN option.
Do not assume that a Si3215 variant is interchangeable merely because its name begins with SI3215. Check the exact suffix, package drawing, temperature grade, electrical limits, and lifecycle status before substitution. The Si3215 also differs from the earlier Si3210 in hardware and software, so a Si3210 PCB requires a complete pin, component, and firmware review rather than a simple connector change.
Treat the ringing and battery sections as potential EMI sources even though both functions are integrated. Use the shortest practical high-current return path, maintain the recommended spacing from sensitive nodes, and provide the prescribed filtering at external line interfaces. EMC performance depends on the complete line network, protection components, chassis or enclosure strategy, and cable configuration, so validate the finished product rather than relying only on IC placement.
The SI3215-KT includes an on-chip DC-DC converter and dynamically generated battery voltage, but external supply decoupling and startup sequencing remain necessary. Follow the manufacturer limits for input voltage, ramp behavior, and power-state transitions. During firmware development, preserve the documented shutdown and restart sequence to avoid forcing an uncontrolled line condition onto a subscriber port.
Route the codec clock and digital interface as a compact, continuous group with a continuous reference return path. Avoid switching nodes beneath these signals and keep the ringing return current out of the codec ground region. Use the manufacturer test points and configuration sequence to verify that clock jitter, codec framing, and DTMF generation remain stable while the line switches between on-hook, off-hook, and ringing states.
Compliance Information
The SI3215 data sheet does not provide enough information in the cited excerpts to assign product-specific RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals status. Confirm these attributes using the exact ordering suffix and the manufacturer's environmental declarations.
