Clock generator with spread-spectrum modulation
The IMISM561BZ is a spread-spectrum clock generator with an integrated PLL, producing a 166 MHz CMOS output from a crystal or clock input. The spread-spectrum modulation reduces peak EMI emissions at the fundamental and harmonic frequencies, which can simplify board-level shielding and filter design in noise-sensitive digital systems. The single-circuit device provides a 1:1 input-to-output ratio with no differential signalling.
Supply rail and temperature constraints for board-fit
A clean 3.3 V rail with ripple below 50 mVpp keeps the PLL jitter within the datasheet limits; a dedicated LDO for the clock generator is advisable if the board's 3.3 V rail also feeds switching regulators. For industrial or automotive applications requiring -40°C to +85°C or wider, a different temperature-grade variant would be needed — no such variant is listed on this record. The 8-SOIC footprint (3.90 mm body width, 1.27 mm pitch) is a standard JEDEC outline. The PCB land pattern follows the standard SOIC-8 recommendation; no thermal pad is required as the device dissipates under 200 mW at 166 MHz output into a 15 pF load.
RoHS compliance is listed as non-compliant. This part likely uses lead-based solder terminations or contains restricted substances in the die-attach or molding compound. For RoHS-required BOMs, a lead-free alternative should be sourced; no pin-compatible RoHS variant is identified on this record.