System Requirements
80 X72 Desiger’s Reference and User’s Guide 097-10603-01 Rev. A – November 2004
Figure D-2 Test Bench setup
System Requirements
The following information lists the requirements for 1 PPS setup and operation:
X72 with 1PPS output enabled.
GPS receiver with less than 300 ns noise.
One pulse per second input signals must have repeatable rise time with minimal
ringing and must conform to the following:
– 1PPS input can be driven by a standard 3.3 volt logic, 5 volt CMOS, or 5
volt TTL with normal operation at:
Input voltage logic high: 2.00V minimum
Input voltage logic high: 5.50V maximum
Input voltage logic low: 0.00V minimum
Input voltage logic low: 0.80V maximum
– Maximum DC overshoot must be limited to 5.5V or 10mA, whichever is
easiest to achieve.
– Maximum DC undershoot must be limited to –0.5V or 10mA, whichever is
easiest to achieve.
– Minimum pulse width (or hold time) of 50 ns.