Infineon Technologies CYIFS784BSXC

Overview

CYIFS784BSXC from Cypress Semiconductor is a 4× spread spectrum clock generator (SSCG) IC designed to reduce EMI in high-speed digital systems by center-spread modulation of input clocks ranging from 6–82 MHz. It accepts crystal, oscillator, or ceramic resonator inputs; delivers TTL/CMOS-compatible 4× modulated output at FSOUT; operates from 3.3 V or 5.0 V supply; and achieves typical power dissipation of 37 mW (3.3 V) or 115 mW (5.0 V). It is used in LCD monitors and DVD drives where EMI compliance must be achieved without waveform degradation.

For engineers reviewing the CYIFS784BSXC datasheet, CYIFS784BSXC pinout, CYIFS784BSXC application, or CYIFS784BSXC equivalent, key selection criteria include confirmed 4× frequency multiplication, programmable 1–4% total peak-to-peak spread bandwidth via external R-C loop filter, center-spread modulation profile, 8-pin SOIC/TSSOP package compatibility, and support for crystal or external clock input on XIN/XOUT pins.

Technical Context

The CYIFS784BSXC implements a PLL-based Direct Digital Synthesis (DDS) architecture with internal modulation control logic that selects one of four input frequency ranges (6–16, 16–32, 32–66, or 66–82 MHz) via S0/S1 digital inputs. Its phase detector output (LF pin) drives an external two-pole passive loop filter to set modulation bandwidth - enabling precise control of total spread (1.0–4.0% peak-to-peak) and modulation rate (e.g., 120× to 720× input divider).

Unlike fixed-bandwidth SSCGs, it requires no internal oscillator - XIN/XOUT pins support parallel-resonant crystals (e.g., 20 MHz) or external CMOS/TTL clocks, with XOUT left unconnected when using non-crystal sources. The FSOUT output maintains tight duty cycle (50% ±5%) and low short-term jitter while sweeping symmetrically around the center frequency.

Key Specifications

Pinout & Package

Available in 8-pin SOIC (CYIFS784BSXC) and TSSOP packages. Pin numbering differs between packages; functional mapping is consistent.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar spread spectrum clock generator applications.

Compared with IDTICS8432AGILF and NB3N3020DR2G, CYIFS784BSXC uniquely supports both 3.3 V and 5.0 V operation, offers full 1–4% spread programmability via external R-C network, and retains SOIC/TSSOP compatibility - making it optimal for cost-sensitive, voltage-flexible, and EMI-margin-critical consumer electronics upgrades.

Availability

CYIFS784BSXC is available at Aetrix Electronics and suitable for LCD displays, DVD drives, and network printers requiring stable component supply with long-term EMI compliance assurance.

Supply support for CYIFS784BSXC includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Cypress Semiconductor (now part of Infineon Technologies) is a fabless semiconductor company specializing in programmable system-on-chip (PSoC), memory, and timing solutions for industrial, automotive, and consumer markets.

CYIFS784BSXC belongs to the FS78x spread spectrum clock generator product line, engineered specifically to reduce radiated EMI in cost-sensitive digital systems without compromising signal integrity or requiring PCB redesign.

FAQ

What is the function of the LF pin on CYIFS784BSXC?

The LF (Loop Filter) pin is the analog output of the internal phase detector. It must be connected to an external two-pole passive R-C loop filter (e.g., R6 = 3.3 kΩ, C7 = 470 pF) to set modulation bandwidth and ensure stable center-spread operation. Leaving LF unfiltered causes erratic or no modulation.

Can CYIFS784BSXC accept a 27 MHz crystal and generate a 108 MHz modulated output?

Yes. With a 27 MHz crystal connected across XIN/XOUT, and S0/S1 configured for the 26–32 MHz input range (S0=0, S1=1), CYIFS784BSXC produces a 4× modulated FSOUT at 108 MHz center frequency, with programmable ±0.54–±2.16 MHz spread depending on loop filter values.

Is CYIFS784BSXC pin-compatible with CYIFS782BSXC?

Yes - both share identical 8-pin SOIC/TSSOP footprints and pin functions (XIN/XOUT, S0/S1, LF, FSOUT, VDD, VSS). The only functional difference is output scaling: CYIFS784BSXC provides 4×, while CYIFS782BSXC provides 2×. No PCB change is needed for upgrade/downgrade.

Does CYIFS784BSXC require an external crystal, or can it use an existing system clock?

It supports both. XIN accepts either a parallel-resonant crystal (with XOUT connected) or a buffered CMOS/TTL clock signal (e.g., from another oscillator or FPGA output). When using an external clock, XOUT must be left unconnected per datasheet guidance.