Linear Technology DC1485A, Demo Manual

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dc1485af
DEMO MANUAL DC1485A
HARDWARE SETUP
Jumpers
MSPAN: Manual Span Control Pin. MSPAN is used to
confi gure the LTC2757 for operation in a single, fi xed
output range. If MSPAN is high it will be confi gured for
single-span use. If MSPAN is low it will be set through the
Quick Eval Software. Default position is 0 (low).
S0, S1, S2: Used to set the fi xed output range if MSPAN
is high. Default position is 0, 0, 0 (0V to 5V).
S2 S1 S0 SPAN
0 0 0 0V to 5V
0 0 1 0V to 10V
0 1 0 ±5V
0 1 1 ±10V
1 0 0 ±2.5 V
1 0 1 –2.5V to 7.5V
REFADJ: Gain Adjust Pin. If no adjustments are required,
select GND. Selecting Ext connects the pin to the turret
allowing external adjustment to null gain error or com-
pensate for reference errors.
RVOS: Offset adjustment selection for DACA. If no offset
adjustment is required, select GND. Selecting EXT connects
the offset pin to the turret allowing external adjustment
of offset.
V
CC
: Select source for 5V V
CC
supply. Set to 5V for supply
by onboard LT1236 reference (recommended). Set to REG
to be supplied by regulated supply from DC590 Controller
and remove the jumper to supply externally.
Analog Connections (Turret Posts)
V
OUT
: DAC Voltage Output.
V
REF
: DAC Reference Voltage. If the onboard LT1236 refer-
ences are selected, the voltage may be measured at these
points. If a remote reference is selected, then an external
reference must be applied to these points.
VOSA: DAC Offset Adjust Input. Use only if VOSA jumper
set to EXT. Nominal input range is ±5V.
REFADJ: Gain Adjust Pin. This voltage-control pin can be
used to null gain error or to compensate for reference er-
rors. The gain error change expressed in LSB is the same
for any output range.
Power and Ground Connections
Analog Power: The 15V, –15V and GND turret posts are
the analog supplies for the internal DAC amplifi ers. These
should be connected to a well regulated, low noise power
supply.
V
CC
: Connection to V
CC
. See schematic and description
for V
CC
jumper.
Grounding: Separate power and signal grounds are pro-
vided. Signal GND is the turret closest to V
OUT
, use this
for measurement ground and output return. Power GND
is between AMP V
+
and AMP V
–
turrets.