SI2457-C-FT 56 kbps V.90 Modem | Skyworks Solutions Inc.
料号： SI2457-C-FT ✓ 量产中SI2457-C-FT 概述
An integrated modem or data access arrangement converts serial digital data into line-frequency signaling compatible with telephone, fax, or data equipment. The SI2457-C-FT combines modulation, data-access, and telephone-line interface functions in one IC, reducing the number of external components required for a conventional modem design. It belongs to the modem IC hierarchy within interface integrated circuits, where protocol conversion and physical-line signaling connect digital hosts to analog communication networks.
Key features include support for data rates through 56 kbps, automatic rate negotiation using MNP2-5, V.42bis error correction, parallel phone detection, DTMF detection, and a built-in phase-locked loop. Its 3.3 V operating point suits modern 3 V digital systems, while the integrated DAA provides galvanic separation from the telephone line through capacitive isolation. The commercial-temperature rating supports indoor telecom, industrial control, fax, and data-communication equipment.
Technically, the SI2457-C-FT is a system-side modem solution rather than a general-purpose transceiver. Its protocol support allows a host processor to establish modem connections across PSTN or equivalent line systems. The built-in phase-locked loop supports stable symbol timing, and the integrated telephone-interface functions simplify the analog line path. Designers should still account for line protection, regional impedance requirements, coupling components, and the complete reference circuit described in the manufacturer data sheet.
Typical uses include legacy fax equipment, remote-access terminals, industrial monitoring links, embedded telephone interfaces, point-of-sale systems, and communications equipment that must support both V.21-class low-speed data and V.90-class 56 kbps operation. The broad protocol set makes the IC useful where interoperability with older telephone infrastructure matters more than raw data throughput or a modern packet-based interface.
A critical design consideration is the telephone-line interface. The manufacturer data sheet specifies the external component values, isolation network, hook and phone-detection circuitry, and layout constraints required for reliable operation. Keep sensitive line-side routing compact, provide the specified protection network, and observe the required creepage and clearance distances for the intended installation class.
This product page consolidates the SI2457-C-FT electrical characteristics, package information, protocol capabilities, application guidance, and confirmed same-package alternatives. It also highlights practical distinctions among closely related Si2457-family devices so engineers can assess footprint reuse, modem features, and implementation constraints before placing a part on a new design.
直接替换替代料： SI2457-C-FT ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
SI2457-D-FT
✅ 直接替换联系询价
查看数据手册 →SI2404-C-FT
✅ 直接替换📋 参考替代料（不在目录中）
SI2457-C-GTR
✅ 直接替换📋 参考替代料（不在目录中）
SI2435-F-FTR
✅ 直接替换📋 参考替代料（不在目录中）
SI2457-C-FT 规格参数
| Device Type | Modem IC |
| Maximum Data Rate | 56 kbps |
| 电源电压 | 3 V to 3.6 V |
| Nominal Supply Voltage | 3.3 V |
| 电源电流 | 26 mA |
| 工作温度 | 0 °C to 70 °C |
| 封装 | 24-pin TSSOP |
| Terminal Count | 24 |
| 安装方式 | Surface mount |
| Terminal Form | Gull wing |
| Supported ITU-T Modem Formats | V.21, V.22, V.23, V.32, V.34, V.90 |
| Supported Bell Modem Formats | Bell 103 and Bell 212A |
| Error Correction | V.42bis |
| Rate Negotiation | MNP2-5 automatic rate negotiation |
| Capacitive Isolation | More than 6000 V |
| Telephone-Line Detection | Parallel phone detect |
| Tone Detection | DTMF detection |
| Clocking Feature | Built-in phase-locked loop |
| Temperature Grade | Commercial |
| RoHS 状态 | Compliant |
| Line Interface | Integrated DAA |
| Minimum Bit Rate | 300 bps |
| Fast Connect Support | Supported |
SI2457-C-FT 24-pin tssop 引脚配置指南
SI2457-C-FT（24-pin tssop 封装）的引脚配置。 引脚编号、功能和连接图在制造商数据手册中定义。请参阅该手册以了解确切的封装尺寸和焊接指南。
暂无详细引脚数据： SI2457-C-FT.
请参阅 数据手册 以查看完整引脚配置。
典型应用
SI2457-C-FT 适用于 6 应用s: Legacy PSTN Data Terminal, Remote Industrial Monitoring, Fax Machine Controller, Telephone Access Terminal, Point-of-Sale Terminal, Embedded Telephone Interface.
Legacy PSTN Data Terminal
The SI2457-C-FT is suitable for a legacy PSTN data terminal that must negotiate connections across several Bell and ITU-T modem standards. Its support for V.21, V.22, V.23, V.32, V.34, and V.90 permits the host to adapt to line quality and counterpart capabilities, while MNP2-5 and V.42bis support improve interoperability and error handling. The 24-pin TSSOP implementation also allows the modem to share a compact controller board with a 3.3 V host processor.
推荐
Remote Industrial Monitoring
The SI2457-C-FT can connect an industrial monitoring controller to a remote site over an analog telephone line. Its 56 kbps V.90 capability is useful for periodic status uploads, configuration retrieval, and diagnostic logs, while lower-rate formats support older infrastructure. The integrated DAA, parallel phone detection, and more than 6000 V capacitive isolation simplify implementation. The 0 °C to 70 °C commercial range suits indoor or temperature-controlled monitoring equipment.
推荐
Fax Machine Controller
The SI2457-C-FT can be used in fax and multifunction-printer controllers that need a compact modem interface and backward-compatible line signaling. Its range of Bell and ITU-T formats allows connection to legacy fax endpoints, while Fast Connect improves session setup for supported equipment. The 24-pin TSSOP package helps reduce board area compared with discrete modem circuitry. Designers should confirm the exact fax-session requirements and use the manufacturer’s required line-interface network.
推荐
Telephone Access Terminal
The SI2457-C-FT fits access terminals that bridge a digital controller to an analog phone line, including voice-messaging interfaces and call-control equipment. Parallel phone detection can help identify an off-hook external device, while DTMF detection supports signaling from telephone equipment. The integrated DAA provides the interface isolation needed in a modem design. Board-level protection and regional telephone-network requirements must still be implemented according to the application’s applicable standards.
推荐
Point-of-Sale Terminal
A point-of-sale terminal can use the SI2457-C-FT for dial-up authentication, transaction synchronization, or remote support when an Ethernet interface is unavailable. Multiple modem formats provide compatibility with existing service endpoints, and the 56 kbps rate is appropriate for short bursts of transactional data. The 3.3 V supply and compact TSSOP package simplify integration near a controller. For higher-volume traffic or contemporary retail networks, a packet-based modem would be more appropriate.
推荐
Embedded Telephone Interface
The SI2457-C-FT is appropriate for embedded equipment requiring an analog telephone-line data port instead of a modern network interface. Its integrated DAA reduces the external modem component count, and its 24-pin TSSOP package supports compact controller hardware. The 3 V to 3.6 V operating range aligns with 3.3 V embedded systems. The manufacturer’s isolation, protection, hook-detection, and line-coupling recommendations should be followed closely to avoid functional or compliance problems.
推荐
推荐产品汇总
工程参考数据： SI2457-C-FT ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | SI2457-D-FT | SI2404-C-FT | SI2457-C-GTR | SI2435-F-FTR |
|---|---|---|---|---|---|
| Package | 24-pin TSSOP | 24-pin TSSOP | 24-pin TSSOP | 24-pin TSSOP | 24-pin TSSOP |
| Brand | Skyworks Solutions Inc. | Skyworks Solutions Inc. | Skyworks Solutions Inc. | Skyworks Solutions Inc. | Skyworks Solutions Inc. |
| Device Type | 56 kbps modem IC | Modem IC | Modem chipset device | 56 kbps modem IC | Fax modem IC |
关键差异点
- Broader 56 kbps modem-format coverage （对比 SI2435-F-FTR)
- Closest orderable configuration match （对比 SI2457-C-GTR)
- Integrated telephone interface （对比 SI2404-C-FT)
设计说明
Use the 24-pin TSSOP land pattern exclusively; the related 16-pin SOIC version is a different footprint. Place the specified input, supply, and bypass capacitors at the pins shown in the manufacturer application circuit, and preserve the recommended ground-return paths. Telephone-line traces should be separated from sensitive host logic, and the isolation and protection components should follow the data-sheet topology rather than a generic modem layout.
Do not treat the SI2457-C-FT and the 16-pin SOIC family option as interchangeable because the lead counts, package dimensions, and pin assignments differ. Also verify that the selected modem format set matches the target telephone network and endpoint. The GTR and FTR order codes identify related ordering variants, so confirm temperature grade, shipping form, and protocol requirements from the manufacturer ordering information before releasing a production BOM.
Keep the telephone-side isolation network and DAA-associated routing as short and controlled as the reference design permits. Observe the applicable clearance and creepage requirements for the equipment category, and use appropriately rated isolation components. A long or poorly controlled line-side return path can degrade modem behavior even when the digital side meets timing requirements, so review the complete phone interface rather than only the TSSOP footprint.
The SI2457-C-FT is rated for a 0 °C to 70 °C ambient range and has a listed 26 mA supply current. Use the TSSOP copper and thermal-relief geometry in the manufacturer layout guidance, then verify the assembled board at the maximum operating ambient temperature. Provide unobstructed thermal paths where practical, especially when the modem is mounted near a power converter, display regulator, or other heat-producing component.
合规信息
RoHS compliance is identified in the component specification. No additional compliance certification claims are made for the other fields.