Datasheet

LTC2756
17
2756f
operaTion
Examples
1. Load ±5V range with the output at 0V. Note that since
span and code are updated together, the output stays
at 0V throughout the example.
a) CS/LD ↓. Clock SDI:
00100000 XXXXXXXX XXXX0010 XXXXXXXX
b) CS/LD ↑
Span Input register – range set to bipolar ±5V.
c) CS/LD ↓. Clock SDI:
00110000 10000000 00000000 00XXXXXX
d) CS/LD ↑
Code Input register – code set to mid-scale.
e) CS/LD ↓. Clock SDI:
01000000 XXXXXXXX XXXXXXXX XXXXXXXX
f) CS/LD ↑
Update code and range.
Alternatively steps e and f could be replaced with
LDAC
.
2. Load ±10V range with the output at 5V, changing to
–5V.
a) CS/LD ↓. Clock SDI:
00110000 11000000 00000000 00XXXXXX
b) CS/LD ↑
Code Input register set to ¾-scale code.
c) CS/LD ↓. Clock SDI:
01100000 XXXXXXXX XXXX0011 XXXXXXXX
d) CS/LD ↑
Span Input register set to ±10V range. Update
code and range. Output goes to 5V.
g) CS/LD ↓. Clock SDI:
01110000 01000000 00000000 00XXXXXX
h) CS/LD ↑
Code Input register set to ¼-scale code. Update
code and range (note update does not change
range, since no new range has been written).
Output goes to –5V.
3. Write and update mid-scale code in 0V to 10V range
(V
OUT
= 5V) using readback to check the contents of
the Input registers before updating.
a) CS/LD ↓. Clock SDI:
00110000 10000000 00000000 00XXXXXX
b) CS/LD ↑
Code Input register set to mid-scale.
c) CS/LD ↓. Clock SDI:
00100000 XXXXXXXX XXXX0001 XXXXXXXX
Data out on SRO:
00000000 10000000 00000000 00000000
Verifies Code Input register set to mid-scale.
d) CS/LD ↑
Span Input register set to 0V to 10V range.
e) CS/LD ↓. Clock SDI:
10100000 XXXXXXXX XXXXXXXX XXXXXXXX
Data out on SRO:
00000000 00000000 00000001 00000000
Verifies Span Input register set to 0V to 10V
range.
f) CS/LD ↑
g) CS/LD ↓. Clock SDI:
01000000 XXXXXXXX XXXXXXXX XXXXXXXX
h) CS/LD ↑
Update code and range. Output goes to 5V.