SI2435-D-FT

Overview

The SI2435-D-FT is a system-side ISOmodem fax modem chipset manufactured by Skyworks Solutions Inc. It supports data rates from 14,400 bps to 33,600 bps over the Public Switched Telephone Network (PSTN). The device integrates a DSP, modem controller, codec, and direct access arrangement (DAA) within a 24-pin TSSOP package. It operates on a digital supply voltage of 3.0 V to 3.6 V and functions within an ambient temperature range of 0 °C to 70 °C for F-grade specifications.

Feature Summary

• Integrates a third-generation silicon direct access arrangement (DAA) providing global telephone line interface compliance without external isolation transformers or relays.
• Supports ITU-T V.34 half duplex fax protocols with automatic rate negotiation and V.8 call establishment capabilities.
• Features a programmable line interface capable of adapting to worldwide PTT specifications for AC/DC termination and ringer impedance.
• Includes built-in caller ID decoding for multiple global standards, DTMF detection/generation, and data/fax discrimination.

Applications

• Fax machines
• Fax telephones
• Multifunctional printers
• Fax servers

Procurement Notes

Verify the specific suffix 'D-FT' against manufacturer documentation to confirm tape-and-reel packaging and lead-free status. Confirm that the component meets RoHS3 requirements and check for any active product lifecycle notices or obsolescence warnings prior to procurement.

Selection Notes

Select this component for applications requiring a compact, globally compliant fax solution. Ensure the host microcontroller supports either UART or parallel interfaces as determined by the AOUT/INT pin state. Verify that the design accommodates the required 4.9152 MHz or 27 MHz clock source for proper operation.

Part Context

This part belongs to the ISOmodem family developed originally by Silicon Laboratories and later acquired by Skyworks Solutions. It is designed as a complete two-chip solution when paired with the Si3018 DAA chip, offering a high level of integration compared to traditional discrete fax modem designs.

Replacement Considerations

Publicly confirmed substitutes include the SI2435-E-FT and SI2435-F-FT. These variants may differ in packaging or minor electrical characteristics; verify datasheet compatibility before replacement.