H-17
Appendix H - AT45 Option (45 Volt Output)
AT45 Option Overview
For channels with AT45 output option, the maximum frequency is limited to 100
kHz. The pulse width can be set over the standard range of the unit with both
active high and low outputs when set to high impedance mode. In low impedance
mode, the pulse width is limited to a maximum of 10s and the active high output
is no longer allowed. To maintain the highest possible rise time, care must be
taken with cabling and termination. Low capacitance cable and 50 ohm
termination will provide the fastest rise times without overshoot. The channel
menu structure for the AT45 module changes are described in the table below
(changes from standard outputs are in bold italics).
AT45 Protection Error Messages
When an AT45 module is present, the system performs self-checks to insure the
module is not damaged when attempting to over-drive.
Module Errors
If a channel on any AT45 module is over-driven, the channel will disable itself
and the system will indicate an error on the module. The error will not clear until
the user presses
FUNC
-
PERIOD
key sequence to clear the error, or power
cycles the instrument.
System Limit Error
The system will not allow the Lo Impedance enabled AT45 channels to exceed
150V total amplitude. If this situation occ
urs, the “Over-Driving Unit” error is
displayed and the currently adjusting amplitude is reduced to the 150V enabled
system limit.
Voltage Change Timing
The channels adjustable voltage changes very quickly when adjusting from a
lower voltage to a higher voltage but changes slowly when changing from a
higher voltage to a lower voltage. It takes approximately 30s to change from 45V
to 3.0V so caution must be taken when adjusting the voltage to a lower voltage
tolerant circuit.
AT45 Channel Menus
Channel Output Configuration Menu
Channel Enable
Channel Enable
Output Type:
High Z
Output Type:
Low Z
Polarity
Output Level
Output Level
