SI2435-E-FT

Modems - ICS And Modules Overview

The SI2435-E-FT is a V.34 fax modem integrated circuit manufactured by Skyworks Solutions Inc., originally developed by Silicon Laboratories. It operates within the ISOmodem family and supports data transmission speeds ranging from 14,400 bps to 33,600 bps over the Public Switched Telephone Network (PSTN). The device utilizes a 24-pin TSSOP package with a width of 4.40 mm. It requires a digital supply voltage (VD) between 3.0 V and 3.6 V. The component supports both UART serial and parallel 8-bit interfaces for host communication.

Modems - ICS And Modules Feature Summary

• Integrates a 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 Class 1 AT command compatibility.
• Includes firmware-upgradable architecture allowing for protocol updates and feature enhancements via host commands.
• Features built-in caller ID decoding, DTMF detection and generation, and data/fax/voice call discrimination capabilities.

Modems - ICS And Modules Applications

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

Modems - ICS And Modules Procurement Notes

Verify the manufacturer designation on official documentation, as the datasheet originates from Silicon Laboratories while distribution is handled by Skyworks Solutions Inc. Confirm that the -E-FT suffix corresponds to the tape and reel packaging format specified in the ordering guide. Ensure the procurement source provides valid RoHS compliance documentation consistent with the F-grade temperature specifications.

Modems - ICS And Modules Selection Notes

Select this component for applications requiring high integration in compact fax systems where external DSPs or codecs are undesirable. The Si2435 specifically supports V.34 HD fax and V.8 call establishment, whereas the Si2417 variant lacks these features. Verify that the host system can support either the default serial UART interface or the parallel interface configuration based on available microcontroller resources.

Modems - ICS And Modules Part Context

This part belongs to the ISOmodem chipset family designed to replace traditional multi-chip fax modem solutions. It pairs with the Si3018 silicon DAA to provide a complete two-chip solution. The product eliminates the need for separate analog front-end components, significantly reducing board space and design complexity for telecommunications equipment manufacturers.

Modems - ICS And Modules Replacement Considerations

Public confirmed substitute part numbers: SI2435-D3-FT, SI2434-D-FTR.

Modems - ICS And Modules FAQ

Does the SI2435 support V.8 call establishment?

Yes, the Si2435 supports V.8 call establishment, allowing it to automatically negotiate with remote modems for the best operational mode and speed, including fallback to G3 fax if V.8 fails.

What clock frequencies are supported by the SI2435?

The device supports a master clock input of either 4.9152 MHz using a crystal across XTALI and XTALO, or a 27 MHz clock signal applied directly to the XTALI pin.

How is the digital interface selected on the SI2435?

Interface selection is determined by the state of the AOUT/INT pin during the rising edge of RESET. An internal pullup forces serial UART mode by default, while an external pulldown resistor forces parallel mode.