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Chapter 8 Tutorial
Multifunction Module
Digital Output
The HP 34907A module has two non-isolated 8-bit input/output ports
which you can use for outputting digital patterns. You can combine the
two ports to output a 16-bit word. A simplified diagram of a single
output bit is shown below.
+5 V
Output
Each output bit is capable of directly driving up to 10 TTL loads
(less than 1 mA). The buffer for each port is used to drive a high
output from the internal +5V supply through the diode. The drive is
rated at +2.4V minimum at 1 mA.
Each output bit is also an active sink, capable of sinking up to
400 mA from an external power supply. The FET is used to sink
currents and has a nominal "on" resistance of 0.2 .
For non- TTL logic you must provide an external pull-up.
A description of the pull-up calculation is given on the following page.
If used with an external power supply and pull-up, the external
supply must be greater than +5 Vdc and less than +42 Vdc.
External Circuit
10 k
I/O Line
(1 of 16)
0.2
+V
8
393
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