ECL/PECL ÷1, ÷2 Clock Generation Chip With Tristate Compatible Outputs

The AZP94 is a specialized 1 or 2 Clock generation part including an enable/reset function. The divide ratio is selected with the DIV-SEL pin/pad. When DIV-SEL is open (NC), the AZP94 functions as a standard receiver. If DIV-SEL is connected to VEE, it functions as a 2 divider. Enable (EN) functionality is selected with the EN-SEL pin/pad which has three valid states: open (NC), VEE, or connected to VEE via a 20k 20% resistor. Leaving EN-SEL open or connecting it to VEE allows the EN pin/pad to function as an active high CMOS/TTL enable. When EN-SEL is open, an internal 75k pull-up resistor is selected which enables the outputs whenever EN is left open. When EN-SEL is connected to VEE, an internal 75k pull- down resistor is selected which disables the outputs whenever EN is left open. Connecting the EN-SEL to VEE with a 20k resistor will allow the EN pin/pad to function as an active low PECL/ECL enable with an internal 75k pull-down resistor. In this mode, outputs are enabled when EN is left open (NC). The default Logic condition CAN be overridden by connecting the EN to VCC with an external resistor of 20k. If the enable signal is CMOS (rail-to-rail) and the Logic sense is active low (EN-SEL connected to VEE with a 20k resistor), the EN pin/pad voltage swing must be reduced using two external resistors. Contact the factory for details. When the AZP94 is disabled, the Q and Q outputs are forced LOW and the input Buffer is powered down to minimize feed through. This feature allows tristate compatible parallel output connections. Multiple AZP94 chip outputs CAN be wired together. Since both outputs are forced LOW in the disable mode, an enabled AZP94 CAN drive the output lines without interference from the unselected units. In addition, the AZP94 CAN be used in parallel connection with PECL/ECL parts whose outputs are high impedance when disabled. The EN pin/pad also functions as a reset when the 2 mode is selected. In the 2 mode, the Counter resets when the outputs are disabled. By Arizona Microtek, Inc.