SP8680B

8PIN CERAMIC DIP high-speed, Emitter-Coupled Logic (ECL) variable modulus divider (also commonly referred to as a prescaler or counter). It is primarily used in high-frequency applications like frequency synthesisers, phase-locked loops (PLLs), and radio frequency (RF) instrumentation. The "B" suffix signifies that this specific model is graded for the standard commercial temperature range - Variable Modulus Division: It functions as a divide-by-10 or divide-by-11 counter.Logic Control: The division ratio is controlled via two ECL-compatible inputs (PE1 and PE2). It divides by 10 if either input is high, and divides by 11 if both inputs are low or left open.State Control: Features an asynchronous Master Set (MS) pin to instantly force the device into the eleventh state.Technical SpecificationsOperating Frequency: Typically operates at very high speeds up to 650 MHz.Cross-Logic Compatibility: Features ECL and TTL compatible outputs, meaning it can interface between different logic families. It can be powered by either ECL supplies (typically 4.75V to 5.5V relative to ground depending on the configuration) or standard TTL 5V supplies.Power Consumption: Consumes roughly 420 mW of power during operation.Form Factor: Usually housed in a 16-pin Ceramic Dual In-line Package (CERDIL16 / DIP).Industry Equivalent: This integrated circuit is the direct functional equivalent to the Fairchild 11C90 prescaler.Common ApplicationsBecause it handles high-frequency division smoothly, it is often found in vintage and legacy RF gear, such as:UHF and VHF frequency synthesisersPhase-Locked Loop (PLL) loop filtersHigh-frequency instrumentation (like frequency counters)Telecommunications and cellular/radio base gear from the late 20th century