LTC2755 Linear Technology, LTC2755 Datasheet - Page 20

• Manufacturer Part Number: LTC2755
• Description: Quad Current Output 12-/14-/16-Bit SoftSpan DACs
• Manufacturer: Linear Technology

www.DataSheet4U.com
LTC2755
APPLICATIONS INFORMATION
Grounding
As with any high resolution converter, clean grounding is
important. A low impedance analog ground plane and star
grounding techniques should be used. I
to the star ground with as low a resistance as possible.
When it is not possible to locate star ground close to
I
pin to star ground. This minimizes the voltage drop from
this pin to ground caused by the code dependent current
fl owing to ground. When the resistance of this circuit
board trace becomes greater than 1Ω, a force/sense am-
plifi er confi guration should be used to drive this pin (see
20
OUT2
, a low resistance trace should be used to route this
V
5V
REF
ALTERNATE AMPLIFIER FOR OPTIMUM SETTLING TIME PERFORMANCE
Figure 2. Optional Circuits for Driving I
1
BAT54S
I
ZETEX
OUT2
1/2 LT1469
2,14, 34, 46
1
2 3
+
–
150pF
6
3
2
OUT2X
LT1468
R
R
COM1
REFA
OFSA
R
IN1
–
+
61
64
63
62
must be tied
2
3
200Ω
200Ω
1000pF
DAC A
OUT2
DAC B
DAC C
DAC D
LTC2755-16
from GND with a Force/Sense Amplifi er.
Figure 2). This preserves the excellent accuracy (1LSB
INL and DNL) of the LTC2755-16.
Layout
Figures 3, 4, 5, and 6 show the layout for the LTC2755
evaluation board, DC1112. This shows how to route
the digital signals around the device without interfering
with the reference and output op amps. Complete demo
board documentation is available in the DC1112 quick
start guide.
I
2755 F02
*SCHOTTKY BARRIER DIODE
OUT2
60
59
58
2
R
I
I
R
OUT1A
OUT2A
FBA
VOSA
1
2
6
–
+
–
+
–
+
3
ZETEX*
BAT54S
LT1001
+
15pF
–
2
3
2
3
–
+
1/2 LT1469
1
V
OUTA
2755f