Microchip | SY89843UMG-TR

The SY89843UMG TR is a low jitter PECL, 2:1 differential input multiplexer (MUX) optimized for redundant source switchover applications. Unlike standard multiplexers, the SY89843U unique 2:1 Runt Pulse Eliminator (RPE) MUX prevents any short cycles or “runt” pulses during switchover. In addition, a unique Fail-Safe Input protection prevents metastable conditions when the selected input clock fails to a DC voltage (voltage between the pins of the differential input drops below 100 mV).

The differential input includes Micrel’s unique, 3-pin input termination architecture that allows customers to interface to any differential signal (AC- or DC-coupled) as small as 100 mV (200 mVPP) without any level shifting or termination resistor networks in the signal path. The output is 800 mV, 100 K compatible LVPECL with fast rise/fall times guaranteed to be less than 190ps. The SY89843U operates from a 2.5 V ±5% or 3.3 V ±10% supply and is guaranteed over the full industrial temperature range of –40°C to +85°C. The SY89843U is part of Micrel’s high-speed, Precision Edge® product line.

Key Features:

• Selects between two sources, and provides a glitch-free, stable LVPECL output.
• Guaranteed AC performance over temperature and supply voltage:
• Wide operating frequency: 1 kHz to >1.5 GHz.
• < 880 ps In-to-Out tpd.
• < 190 ps tr/tf.
• Unique patent-pending input isolation design minimizes crosstalk.
• Fail-Safe Input prevents oscillations.
• Ultra-low jitter design:
• <1 psRMS random jitter.
• <1 psRMS cycle-to-cycle jitter.
• <10 psPP total jitter (clock).
• <0.7 psRMS MUX crosstalk induced jitter.
• Unique patent-pending input termination and VT pin accepts DC- and AC-coupled inputs (CML, PECL,
• VDS).
• 800 mV LVPECL output swing
• 2.5 V ±5% or 3.3 V ±10% supply voltage.
• –40°C to +85°C industrial temperature range.
• Available in 24-pin (4 mm x 4 mm) MLF™ package.

Applications:

• Redundant clock switchover.
• Fail-safe clock protection.