SI2435-A-FT

Overview

The SI2435-A-FT is a V.34 fax modem integrated circuit manufactured by Skyworks Solutions Inc., originally developed by Silicon Laboratories. It operates within a digital supply voltage range of 3.0 to 3.6 V and supports an ambient temperature range of 0 to 70 °C for the F-Grade variant. The device provides data transmission speeds ranging from 14,400 bps to 33,600 bps over the Public Switched Telephone Network (PSTN). It utilizes a 24-pin TSSOP package and interfaces via UART or parallel bus.

Feature Summary

• Integrated Direct Access Arrangement (DAA) providing global telephone line interface compliance
• Supports ITU-T V.34 half duplex fax protocols with automatic rate negotiation
• Includes on-chip DSP, modem controller, codec, and memory eliminating external components
• Capable of distinctive ring detection, caller ID decoding, and DTMF generation

Applications

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

Procurement Notes

Verify the manufacturer origin as the datasheet identifies Silicon Laboratories as the developer while Skyworks holds distribution rights. Confirm the specific suffix 'A' matches the required revision against official ordering guides. Ensure the component meets RoHS standards if applicable to the target assembly process.

Selection Notes

Select this model for applications requiring a complete two-chip fax solution with minimal external parts. Verify compatibility with the paired Si3018 silicon DAA chip. Ensure the host system supports either serial UART or parallel 8-bit interface modes based on hardware configuration requirements.

Part Context

This component belongs to the ISOmodem family of fax modems. It is designed to replace discrete solutions involving separate DSPs, controllers, codecs, and isolation transformers. The chipset architecture allows for significant reduction in board space and design complexity for legacy telephone network equipment.

Replacement Considerations

SI2435-F-FT

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.

What are the supported clock input frequencies?

The device supports a default 4.9152 MHz crystal input or a 27 MHz master clock input via the XTALI pin.

How is the digital interface mode selected?

Interface selection is determined by the state of the AOUT/INT pin during the rising edge of RESET; an internal pullup defaults to serial mode, while a pulldown forces parallel mode.