General Description

The SY10/100EL34/L are low-skew ÷2, ÷4, ÷8 clock generation chips designed explicitly for low-skew clock generation applications. The internal dividers are synchronous to each other; therefore, the common output edges are all precisely aligned. The devices can be driven by either a differential or single-ended ECL or, if positive power supplies are used, PECL input signal. In addition, by using the VBB output, a sinusoidal source can be AC coupled into the device. If a single-ended input is to be used, the VBB output should be connected to the CLK input and bypassed to ground via a 0.01µF capacitor. The VBB output is designed to act as the switching reference for the input of the EL34/L under single-ended input conditions. As a result, this pin can only source/sink up to 0.5mA of current.

The common enable (EN ) is synchronous so that the internal dividers will only be enabled/disabled when the internal clock is already in the LOW state. This avoids any chance of generating a runt clock pulse on the internal clock when the device is enabled/disabled as can happen with an asynchronous control. An internal runt pulse could lead to losing synchronization between the internal divider stages. The internal enable flip-flop is clocked on the falling edge of the divider stages. The internal enable flip flop is clocked on the falling edge of the input clock; therefore, all associated specification limits are referenced to the negative edge of the clock input.

Upon start-up, the internal flip-flops will attain a random state; the master reset (MR) input allows for the synchronization of the internal dividers, as well as for multiple EL34/Ls in a system.

Features

• 3.3V and 5V power supply options

• 50ps output-to-output skew

• Synchronous enable/disable

• Master Reset for synchronization

• Internal 75KΩ input pull-down resistors

• Available in 16-pin SOIC package