Infineon Technologies W181-01G

Overview

W181-01G from Cypress Semiconductor is a spread spectrum clock generator (SSCG) IC designed to reduce electromagnetic interference in digital systems by modulating output clock frequency. It supports 3.3V or 5V supply, operates with input frequencies from 28 MHz to 75 MHz, delivers ≤300 ps cycle-to-cycle jitter, and offers selectable 1.25% or 3.75% down-spread modulation for EMI suppression in PC motherboards and embedded controllers.

For engineers reviewing the W181-01G datasheet, W181-01G pinout, W181-01G application, or W181-01G equivalent, this device is selected for EMI-critical timing paths where deterministic frequency deviation, low-jitter clock synthesis, and dual-voltage compatibility are required - not as a general-purpose oscillator or crystal driver.

Technical Context

The W181-01G implements a PLL-based spread spectrum frequency timing generator with integrated loop filter components. It accepts either an external clock (CLKIN) or crystal reference (X1/X2), locks output frequency to input (1:1 ratio), and superimposes a fixed-frequency triangular modulation waveform at the VCO input to achieve controlled frequency deviation.

Modulation width (1.25% or 3.75% down-spread) is selected via SS% pin; frequency range (28–75 MHz) is set by FS1/FS2 pins with internal pull-up resistors; SSON# enables/disables modulation via active-low control with internal pull-down. Output duty cycle remains within 40/60% worst-case across operating conditions.

Key Specifications

Pinout & Package

W181-01G is housed in an 8-pin plastic SOIC (150-mil) package with gull-wing leads, RoHS-compliant, rated for 0°C to +70°C commercial operation.

Key Features

Applications

Equivalent & Alternatives

Cypress W181-01G has documented alternatives offering comparable spread spectrum functionality and pin-compatible footprints.

Compared with IDT 8T49N241 and ON Semi NB3N3020B, W181-01G uniquely balances hardware-configurable spread/frequency selection, dual-voltage support, and minimal external component count - making it optimal for fixed-function EMI reduction in industrial and computing platforms.

Availability

W181-01G is available at Aetrix Electronics and suitable for PC motherboard design, industrial PLC timing, network switch clocking, and medical imaging data acquisition requiring stable component supply and long-term EMI compliance assurance.

Supply support for W181-01G 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 U.S.-based semiconductor company specializing in programmable system-on-chip, memory, and timing solutions for industrial, automotive, and communications markets.

The W181 series belongs to Cypress's PREMIS™ family of spread spectrum timing generators, engineered specifically to meet stringent EMI regulations in high-speed digital systems without mechanical shielding or board redesign.

FAQ

What is the function of the SSON# pin on W181-01G?

The SSON# pin is an active-low spread spectrum enable control. When pulled LOW (internally pulled down), it activates the internal modulation waveform, causing the CLKOUT signal to sweep across a narrow frequency band. When held HIGH, modulation is disabled and CLKOUT passes through the input clock unchanged. This allows runtime EMI control during system debug or low-noise test modes.

Can W181-01G operate with a crystal connected between X1 and X2?

Yes - W181-01G supports crystal oscillator mode using pins 1 (X1) and 2 (X2). In this configuration, the internal oscillator circuit forms a Pierce oscillator with the external crystal and load capacitors. Pin 2 must be connected to the crystal's second terminal; no external inverter or capacitors are needed beyond standard crystal load network values specified in the datasheet.

How does the FS1/FS2 pin combination affect W181-01G operation?

FS1 and FS2 are 2-bit frequency range select inputs that configure the internal PLL dividers for optimal lock stability across four input bands: 28–38 MHz, 38–48 MHz, 46–60 MHz, and 58–75 MHz. Each combination sets different charge pump gain and loop filter response; incorrect strapping causes extended lock time or failure to acquire phase lock at edge frequencies.

Is W181-01G compatible with 5V-tolerant I/O interfaces?

No - W181-01G is not 5V-tolerant on input pins. While it accepts 5V supply (VDD), its logic inputs (FS1, FS2, SS%, SSON#) are CMOS-compatible with VDD levels only: VIH = 0.7×VDD and VIL = 0.3×VDD. Driving these pins from 5V logic while operating at 3.3V supply violates absolute maximum ratings and may cause latch-up or permanent damage.