Demonstration circuit 2837A is easy to set up to evaluate
the performance of the LTC2063/LTC2066. The DC2837A
board provides multiple empty mostly-0805 component
footprints for users to configure the LTC2063/LTC2066
as desired.
The default configuration of the board is in
unity gain/
buffer with split supplies (V
+
and V
–
)
.
Refer to Figure 1 for a generic schematic, Figure 2 for
measurement equipment setup, and Table 1 for a jumper
table, and follow the procedure below.
Note:
Unless otherwise specified, leave jumpers in
default positions, and components unstuffed. Table 1
explains each jumper setting in further detail.
1. Verify that jumper
JP6
for
SHDN
is on position 1,
labeled
EN
, so that the part is enabled.
2. Verify that jumper
JP4
is across 2–3 for GND so the
board is in split supply mode.
3. Set the power supply’s positive output to +2.5V and
the negative output to –2.5V.
Note:
The supply limits are
±2.62V
in
split
sup-
ply, and
1.7V to 5.25V
in
single
-supply (V
–
= GND)
configuration.
4. With power off, connect the power supply to the row
of turrets at the top of the board: + supply to V
+
tur-
ret, –supply to V
–
turret, and COM to GND turret.
5. Connect a signal generator either at the +IN and GND
turrets or at the +IN SMA input. A 100Hz sine wave
with 0V offset and 0.5V
P-P
is a good starting point.
Note:
The input lowpass filter at IN
+
has a cutoff
of 480Hz for DC2837A-A (LTC2063) and 2.4kHz
for DC2837A-B (LTC2066).
6. Connect an Oscilloscope 10× probe to the OUT turret.
Clip scope probe GND to a GND turret. Set the scaling
to 100mV/2ms per division.
7. Power-up the system. A 100Hz 0.5V
P-P
sine wave
centered at 0V should appear on the oscilloscope.
8. Increase the signal amplitude and observe the signal
for clipping as signals reach the supply rails. Slew
and settling behavior can be evaluated by switching
the signal generator to square wave.
9. To evaluate shutdown performance, move the jumper
at
JP6
to position 3, labeled
DIS
, tying
SHDN
to V
–
.
To re-enable the part, move the
JP6
jumper back to
EN
(position 1).
10.
OPTIONAL:
To evaluate shutdown performance with
a shutdown control signal,
remove any jumper con-
nectors on JP6 completely
. Connect a signal gen-
erator to the
SHDN
turret and GND. Set the signal
generator to a 5V
P-P
, 0V offset, 1Hz square wave.
Keep the input sine wave on. Adjust oscilloscope
time scale to 100ms/div at least. Observe the part’s
output shutting down and returning, and the supply
current dropping when shut down and rising again
when turned back on.
Table 1. Jumper Table
JUMPER
POSITION 1
OR STUFFED*
POSITION 3
OR UNSTUFFED*
NOTES
JP1
V
+
V
–
Add DC Offset, or
Connects Filter
Component Z1 to –IN
JP2*
Ties –IN to V
+
or V
–
via Z1
Disconnects
–IN from V
+
or
V
–
via Z1
Z1 Unstuffed by Default
JP3
V
+
V
–
Add DC Offset to +IN;
R9, R10 Allow for
Scaling/Dividing
JP4
V
–
Tied to GND
(Single-Supply)
Separate
V
–
and GND
(Split Rail)
3rd Position GND for
Jumper Storage when
Using Split Rails
JP5
Add Z2 in
Parallel with R5
Feedback
Short Out R6
in Series with
Output
Default Open Path
(Z2 Unstuffed)
JP6
V
+
, Enable
V
–
, Disable
Remove Jumper
Completely if Using
External
SHDN
Control
* Two-Terminal Jumper ONLY (JP2)
2
DEMO MANUAL
Rev. 0
QUICK START PROCEDURE
