LTC2754 LINER [Linear Technology], LTC2754 Datasheet - Page 15

• Manufacturer Part Number: LTC2754
• Description: Quad 12-/16-Bit SoftSpan IOUT DACs
• Manufacturer: LINER [Linear Technology]

OPERATION
Readback in M-Span Confi guration
If the part is in M-Span confi guration and a DAC Span
register is specifi ed for readback, then the data shifted out
of SRO will refl ect the actual active span. The hardware-
confi gured output range is therefore software detectable
and available for use in programming.
Examples
1. Using a 24-bit instruction, load DAC A with the unipolar
range of 0V to 10V, output at zero volts and all other DACs
with the bipolar range of ±10V, outputs at zero volts. Note
all DAC outputs should change at the same time.
a) CS/LD↓
b) CS/LD↑
±10V.
c) CS/LD↓
d) CS/LD↑
e) CS/LD↓
f) CS/LD↑
g) CS/LD↓
h) CS/LD↑
i) CS/LD↓
j) CS/LD↑
k) Alternatively steps i and j could be replaced with
Clock SDI = 0010 1111 0000 0000 0000 0011
Input register- Range of all DACs set to bipolar
Clock SDI = 0010 0000 0000 0000 0000 0001
Input register- Range of DAC A set to unipolar 0V
to 10V.
Clock SDI = 0011 1111 1000 0000 0000 0000
Input register- Code of all DACs set to midscale.
Clock SDI = 0011 0000 0000 0000 0000 0000
Input register- Code of DAC A set to zero code.
Clock SDI = 0100 1111 XXXX XXXX XXXX XXXX
Update all DACs for both Code and Range.
LDAC
.
2. Using a 32-bit load sequence, load DAC C with bipolar
±2.5V and its output at zero volts. Use readback to check
Input register contents before updating the DAC output
(i.e., before copying Input register contents into DAC
register).
a) CS/LD↓ (Note that after power-on, the code in
b) CS/LD↑
c) CS/LD↓
d) CS/LD↑
e) CS/LD↓
f) CS/LD↓
g) CS/LD↑
h) Alternatively steps f and g could be replaced with
Input register is zero)
Clock SDI = 0000 0000 0011 0100 1000 0000
0000 0000
Input register- Code of DAC C set to midscale
setting.
Clock SDI = 0000 0000 0010 0100 0000 0000
0000 0100
Data out on SRO = 1000 0000 0000 0000 Verifi es
that Input register- Code DAC C is at midscale
setting.
Input register- Range of DAC C set to Bipolar
±2.5V range.
Clock SDI = 0000 0000 1010 0100 xxxx xxxx
xxxx xxxx
Data Out on SRO = 0000 0000 0000 0100
Verifi es that Input register- range of DAC C set to
Bipolar ±2.5V Range.
CS/LD↑
Clock SDI = 0000 0000 0100 0100 xxxx xxxx
xxxx xxxx
Update DAC C for both Code and Range
LDAC
.
LTC2754
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