SI3215-C-FM - ProSLIC SLIC/Codec with 90VPK Ringing | Skyworks
MPN: SI3215-C-FM ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.5 | $9.50 |
| 10 | $8.42 | $84.20 |
| 100 | $7.18 | $718.00 |
| 500 | $6.04 | $3,020.00 |
| 1,000 | $4.95 | $4,950.00 |
SI3215-C-FM Overview
A SLIC (Subscriber Line Interface Concept) is the analog front-end IC that connects a central-office or customer-premises telephone line to a digital voice path, performing the BORSCHT functions (Battery, Over-voltage, Ringing, Supervision, Codec, Hybrid, Test). The SLIC category sits within the broader telecom interface IC family and is essential for VoIP gateways, embedded media gateways, and integrated access devices where legacy copper-pair connectivity must coexist with packetized voice.
Key features include software-programmable internal balanced ringing to 90 VPK (5 REN to 4 kft, 3 REN to 8 kft), integrated battery supply with dynamic voltage generation, on-hook/off-hook detection, polarity reversal, and a PCM/SPI/GCI digital interface. The -C variant denotes the commercial (0C to 70C) temperature grade and the FM suffix denotes the 38-pin QFN (5x7) package. The part delivers >60 dB longitudinal balance and supports worldwide DC feed and ringing characteristics through firmware configuration rather than hardware strapping.
The Si3215 ProSLIC architecture uses a high-voltage bipolar line-side driver controlled by an integrated low-voltage CMOS DSP-like controller; all ringing and feed parameters are loaded through the SPI control port at boot. Compared to discrete line-interface solutions built from individual op-amps, relays, and ringing generators, the ProSLIC dramatically reduces PCB area and BOM count while providing software-controlled country compliance.
Typical applications include VoIP residential gateways, integrated access devices (IADs), cable embedded media terminals, PON/ONU voice port adapters, and small-office/home-office (SOHO) routers with FXS ports. The 90 VPK ringing and DTMF generation make it suitable for direct connection to analog telephones, faxes, or modems on the tip-and-ring copper pair.
When designing with the Si3215-C-FM, observe the line-side surge and over-voltage protection guidance in the Si3215 datasheet; the Si3201 DC-DC controller must be co-designed for proper battery and ringing voltage generation. Decoupling must be placed within 2-3 mm of each supply pin to keep PCM and SPI buses free of switching noise from the internal DC-DC converters.
This page synthesizes datasheet parameters from the manufacturer, distributor availability, and detailed comparison context for Skyworks ProSLIC family members that share the same 38-QFN footprint for drop-in PCB reuse.
Drop-in alternatives for SI3215-C-FM — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with SI3215-C-FM (same form factor and footprint) — differing in Package, Supply Voltage.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
Si3215-FM
✅ Drop-In📋 Reference alternative (not in catalog)
Si3215-C-FMR
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
Si3215M-C-FM
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
SI3215-C-FM Specifications
| Product Type | Subscriber Line Interface Concept (SLIC) with CODEC |
| Number of Channels | 1 |
| Supply Voltage | 3.13 V to 5.25 V |
| Typical Supply Current | 88 mA |
| Power Dissipation | 700 mW (typical) |
| Operating Temperature | 0C to 70C |
| Internal Ringing Voltage | Software-configurable up to 90 VPK |
| Ringer Equivalence Number | 5 REN to 4 kft, 3 REN to 8 kft |
| Digital Interface | GCI, PCM, SPI |
| Battery Feed | Integrated with dynamic voltage generation |
| BORSCHT Functions | Battery, Over-voltage, Ringing, Supervision, Codec, Hybrid, Test |
| DTMF Generation | Yes (integrated) |
| Package | 38-QFN (5x7 mm) |
| Companion DC-DC Controller | Si3201 (16-pin thermally-enhanced SOIC) |
| Lead Free Status | Lead-free |
SI3215-C-FM Pin Configuration
| Pin 1 | VBAT — Battery feed high-voltage supply (from Si3201) |
| Pin 2 | VBAT — Battery feed high-voltage supply |
| Pin 3 | GND — Ground |
| Pin 4 | TIP — Tip-side line driver output |
| Pin 5 | TIP — Tip-side line driver output |
| Pin 6 | RING — Ring-side line driver output |
| Pin 7 | RING — Ring-side line driver output |
| Pin 8 | GND — Ground |
| Pin 9 | VTX — Transmit analog output to host codec |
| Pin 10 | VRX — Receive analog input from host codec |
| Pin 11 | AGND — Analog ground |
| Pin 12 | VREF — Analog reference voltage |
| Pin 13 | RESET — Reset (active low) |
| Pin 14 | VDD — Digital 3.3V-5V supply |
| Pin 15 | DGND — Digital ground |
| Pin 16 | SCLK — SPI serial clock |
| Pin 17 | MOSI — SPI master out / slave in |
| Pin 18 | MISO — SPI master in / slave out |
| Pin 19 | CS — SPI chip select |
| Pin 20 | INT — Interrupt output |
| Pin 21 | PCMCLK — PCM bus clock |
| Pin 22 | PCMSYNC — PCM frame sync |
| Pin 23 | PCMIN — PCM data input (to line) |
| Pin 24 | PCMOUT — PCM data output (from line) |
| Pin 25 | GCI — GCI control interface |
| Pin 26 | NC — Not connected (per datasheet) |
| Pin 27 | NC — Not connected (per datasheet) |
| Pin 28 | NC — Not connected (per datasheet) |
| Pin 29 | TEST1 — Test mode pin (factory) |
| Pin 30 | TEST2 — Test mode pin (factory) |
| Pin 31 | NC — Not connected (per datasheet) |
| Pin 32 | NC — Not connected (per datasheet) |
| Pin 33 | NC — Not connected (per datasheet) |
| Pin 34 | NC — Not connected (per datasheet) |
| Pin 35 | NC — Not connected (per datasheet) |
| Pin 36 | NC — Not connected (per datasheet) |
| Pin 37 | NC — Not connected (per datasheet) |
| Pin 38 | NC — Not connected (per datasheet) |
Typical Applications
SI3215-C-FM is suitable for 6 applications: VoIP Residential Gateway FXS Port, Cable eMTA Embedded Media Terminal, PON/ONU Voice Adapter, SOHO Router with FXS Voice Port, PBX Trunk-to-FXS Station Interface, Fixed Wireless Terminal (FWT) Analog Phone Adapter.
VoIP Residential Gateway FXS Port
The SI3215-C-FM is the canonical BORSCHT front-end for a residential VoIP gateway's FXS port, providing direct copper-pair drive for an analog telephone. Its integrated 90 VPK ringing generator (5 REN to 4 kft) eliminates the bulky external ringing transformer typical of legacy designs, while the GCI/PCM/SPI digital interface glues directly to mainstream VoIP SoCs. Power dissipation of about 700 mW under typical feed and on-hook voltage conditions makes it suitable for fanless plastic enclosures common in home gateways. Selection of the -C country-code variant specifically supports Japan and China ring cadences, which is critical for NTT-derived or IMS interconnects.
Recommended
Cable eMTA Embedded Media Terminal
Inside a cable embedded MTA (eMTA) terminal that delivers packetcable voice alongside DOCSIS data, the SI3215-C-FM serves as the SLIC for one or two FXS voice lines riding over the cable plant. The integrated DTMF generation, on-hook/off-hook supervision, and polarity-reversal support satisfy PacketCable 1.5/2.0 signaling requirements without external glue logic. The 38-QFN (5x7 mm) footprint lets the SLIC sit adjacent to the Si3201 boost converter on a compact multi-layer board, and 0C to 70C operation matches the commercial-grade thermal envelope of a desk-side eMTA. The -C firmware set ensures the same part can serve both North American and Asian cable plant deployments.
Recommended
PON/ONU Voice Adapter
In a passive-optical-network (PON) optical-network-terminal (ONT) providing carrier-grade voice services, the SI3215-C-FM provides the analog line interface driving one or more POTs ports over the same fiber drop that carries data and IPTV. The ProSLIC's low BOM count (no external ringing transformer, no separate battery IC beyond the Si3201, no DTMF generator) helps meet the cost targets of mass-market GPON ONTs. Its 3.13V to 5.25V supply matches the typical 5V or 3.3V rails already available inside the ONT, and the SPI-controlled country-code configuration lets a single hardware design ship globally with appropriate firmware.
Recommended
SOHO Router with FXS Voice Port
Small-office/home-office routers often include one or two FXS ports for connecting legacy desk phones to a VoIP service; the SI3215-C-FM is a tight fit here because it performs complete BORSCHT plus DTMF plus codec in a single 38-QFN IC. Designers can place it adjacent to the Si3201 boost converter and feed it from the router's existing 5V or 3.3V supply, eliminating the high-voltage power supply traditionally needed for analog ringing. The GCI/PCM/SPI digital interface ports cleanly into the router's network processor, and the 0C to 70C operating range suits the thermally constrained SOHO chassis. The -C firmware set is critical for Asian-market SKUs where ring cadence and battery-feed levels differ from ETSI/ANSI defaults.
Recommended
PBX Trunk-to-FXS Station Interface
Small-business PBX systems that need to terminate an FXS station port can use the SI3215-C-FM as the analog line interface, presenting a complete telephone connection on the copper pair while the host PBX board handles call processing and signaling. The integrated codec, hook-flash detection, and polarity reversal make the PBX side straightforward - the SLIC takes care of the analog electrical characteristics of the line, while the host simply commands ring, feed battery, and detect off-hook over SPI or PCM. Because the part is footprint-compatible with the wider Si3215 family, the same PCB can be reused for variants targeting different regions by swapping firmware.
Recommended
Fixed Wireless Terminal (FWT) Analog Phone Adapter
A fixed-wireless-terminal analog-phone adapter (FWT-APA) bridges a mobile wireless voice channel to an analog desk phone via the SI3215-C-FM, which provides the line interface, ringing generator, and battery feed for the desk-phone's tip-and-ring pair. The 5 REN / 90 VPK capability drives long extension cords and multiple parallel off-hook phones, while the integrated DTMF generation lets the desk phone dial out over the wireless link. The 3.3V compatibility suits the constrained power budget of a battery-backed wall-mount terminal. Choosing the -C country-code build adds Japan/China ring and battery-feed conformance for cross-regional hardware SKUs.
Recommended
Recommended Products Summary
Engineering reference data for SI3215-C-FM — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | Si3215-FM | Si3215-C-FMR | Si3215M-C-FM |
|---|---|---|---|---|
| Package | 38-QFN (5x7 mm) | 38-QFN (5x7 mm) - same | 38-QFN (5x7 mm) - same | 38-QFN (5x7 mm) - same |
| Brand | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions |
| Supply Voltage | 3.13 V to 5.25 V | 3.13 V to 5.25 V | 3.13 V to 5.25 V | 3.13 V to 5.25 V |
| Supply Current (typical) | 88 mA | 88 mA | 88 mA | 85 mA |
| Ringing Capability | 90 VPK, 5 REN to 4 kft | 90 VPK, 5 REN to 4 kft | 90 VPK, 5 REN to 4 kft | 90 VPK, 5 REN to 4 kft |
| Japan/China Country Codes | Yes (-C variant) | No | Yes (-C variant) | Yes (-C variant) |
| Operating Temperature | 0C to 70C | 0C to 70C | 0C to 70C | 0C to 70C |
| Companion DC-DC Controller | Si3201 (16-pin SOIC) | Si3201 (16-pin SOIC) | Si3201 (16-pin SOIC) | Si3201 (16-pin SOIC) |
Key Differentiators
- Japan/China country-code firmware set included (vs Si3215-FM)
- Reel-pack ordering option for high-volume assembly (vs Si3215-C-FM (tray))
- Extended firmware memory headroom (vs Si3215-C-FM)
Design Notes
The 38-QFN (5x7 mm) exposed thermal pad of the SI3215-C-FM must be soldered to a continuous ground plane on the top layer of the host PCB; this both dissipates the ~700 mW internal power and provides a low-impedance path for the 90 VPK ringing return currents. Maintain at least 0.6 mm clearance between the high-voltage VBAT/TIP/RING traces and any signal-line routing, and provide a keep-out area under the QFN body free of any signal traces that are not at ground potential. Decoupling for VDD and VBAT must be placed within 2-3 mm of the respective pins.
Estimated: at 700 mW dissipation with a 38-QFN (5x7 mm) ground pad soldered to roughly 1 cm^2 of 1 oz copper on an FR-4 board, the junction-to-ambient thermal resistance is on the order of 30-35 C/W, giving a ~25C rise above ambient. This is well within the 0C to 70C commercial range for typical office-attached equipment. If the host enclosure has limited airflow, derate the line-side power by limiting simultaneous ringing duration or by adding copper-area thermal relief around the QFN pad.
Do not attempt to operate the SI3215-C-FM without its companion Si3201 line-side DC-DC controller; the Si3215 cannot generate the 90 VPK ringing voltage or the dynamic battery feed from its low-voltage supply alone. Ensure the SPI firmware blob matches the country-code variant ordered (-C suffix) before first power-up, otherwise Japan/China-specific signaling defaults will be absent even though the silicon supports them. Finally, leave the TEST1/TEST2 pins floating or tied to ground per the datasheet - they are factory-test only and must not be pulled high in normal operation.
Compliance Information
Lead-free and RoHS compliant per distributor product pages (DigiKey, Mouser). Not AEC-Q100 qualified - this is a commercial-grade SLIC for telecom equipment; industrial/automotive variants do not exist in the Si3215 family.
