A62 Motherboard Overall Description - HP 8340B Manual

A62 Motherboard
Overall Description
ASSEMBLY PURPOSE
The A62 motherboard
is the common board to which many other assemblies are connected and
serves to route signals
between these assemblies. The A62 motherboard also routes signal to and
from the front/rear
panel connectors.
GROUNDS
The A62 motherboard
has several different grounds:
•
STAR GND
—
is the single ground reference point for analog
circuitry
in all
major assemblies.
Each assembly block is
referenced to
STAR GND via individual traces, minimizing ground noise
crosstalk between major
assemblies. STAR
GND
is
a
screw terminal located between the
A62XA57 marker bandcross connector
and
A62J3 connector and
is
visible with the instrument top
cover removed.
•
GND
—
designates
individual analog
ground traces connecting major assembly
blocks
to STAR
GND. Many of these
traces are physically large and
are
used for high current
power supply
applications.
•
GND PLANE
-
Refer to Figure
E-1.
Figure E-1.
A62
Motherboard Cross Section
ANALOG SIGNALS
DIGITAL GROUND PLANE
DIGITAL
SIGNALS
DIGITAL SIGNALS
DIGITAL GROUND PLANE
ANALOG SIGNALS
HP 8340B/41B
A62 Motherboard Overall
Description E-l