LTC1589IG View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LTC1589IG' PDF : 16 Pages View PDF
LTC1588/LTC1589/LTC1592
APPLICATIO S I FOR ATIO
While not directly addressed by the simple equations in
Tables 2 and 3, temperature effects can be handled just as
easily for unipolar and bipolar applications. First, consult
an op amp’s data sheet to find the worst-case VOS and IB
over temperature. Then, plug these numbers in the VOS
and IB equations from Table 3 and calculate the tempera-
ture induced effects.
For applications where fast settling time is important, Appli-
cation Note 74, entitled “Component and Measurement
Table 2. Variables for Each Output Range That Adjust the
Equations in Table 3
OUTPUT RANGE
A1
A2
A3 A4
A5
5V
1.1
2
1
10V
2.2
3
1.5
±5V
2
2
1.2
1
1.5
±10V
4
4
1.2
1
2.5
±2.5V
1
1
1.6
1
1
–2.5V to 7.5V
1.9
3
1
0.5
1.5
Advances Ensure 16-Bit DAC Settling Time,” offers a thor-
ough discussion of 16-bit DAC settling time and op amp
selection.
Precision Voltage Reference Considerations
Much in the same way selecting an operational amplifier
for use with the LTC1592 is critical to the performance of
the system, selecting a precision voltage reference also
requires due diligence. The output voltage of the LTC1592
is directly affected by the voltage reference; thus, any
voltage reference error will appear as a DAC output voltage
error.
There are three primary error sources to consider when
selecting a precision voltage reference for 16-bit applica-
tions: output voltage initial tolerance, output voltage tem-
perature coefficient and output voltage noise.
Initial reference output voltage tolerance, if uncorrected,
generates a full-scale error term. Choosing a reference
Table 3. Easy-to-Use Equations Determine Op Amp Effects on DAC Accuracy in All Output Ranges
OP AMP
INL (LSB)
DNL (LSB)
( ) ( ) 5V
VOS1 (mV) VOS1 • 2.4 • VREF
5V
VOS1 • 0.6 • VREF
( ) ( ) IB1 (nA)
IB1 • 0.0003 •
5V
VREF
IB1
•
0.00008 •
5V
VREF
AVOL1 (V/V)
( ) A1 •
16.5k
AVOL1
( ) A2 •
1.5k
AVOL1
UNIPOLAR
OFFSET (LSB)
( )5V
VOS1 • 13.2 • VREF
( ) IB1 • 0.13 •
5V
VREF
0
VOS2 (mV)
0
0
0
IB2 (mV)
0
0
0
AVOL2 (V/V)
0
0
0
BIPOLAR ZERO
UNIPOLAR GAIN
BIPOLAR GAIN
ERROR (LSB)
ERROR (LSB)
ERROR (LSB)
( ) ( ) ( ) 5V
5V
5V
A3 • VOS1 • 19.8 • VREF VOS1 • 13.2 • VREF VOS1 • 13.2 • VREF
( ) ( ) ( ) IB1 • 0.01 •
5V
VREF
IB1 • 0.0018 •
5V
VREF
IB1 • 0.0018 •
5V
VREF
0
( ) A5 •
131k
AVOL1
( ) A5 •
131k
AVOL1
( ( )) ( ) ( ) A4 •
VOS2 • 13.1 •
5V
VREF
VOS2 • 26.2 •
5V
VREF
VOS2 • 26.2 •
5V
VREF
( ( )) ( ) ( ) A4 •
IB2 • 0.05 •
5V
VREF
IB2 • 0.1 •
5V
VREF
IB2 • 0.1 •
5V
VREF
( ) A4 •
66k
AVOL2
( ) 131k
AVOL2
( ) 131k
AVOL2
Table 4. Partial List of LTC Precision Amplifiers Recommended for Use with the LTC1588/LTC1589/LTC1592,
with Relevant Specifications
AMPLIFIER SPECIFICATIONS
VOS
AMPLIFIER
µV
VOLTAGE CURRENT SLEW GAIN BANDWIDTH tSETTLING
IB
AOL
NOISE
NOISE
RATE
PRODUCT
with LTC1592
nA
V/mV
nV/√Hz
pA/√Hz
V/µs
MHz
µs
LT1001
25
2
800
10
0.12
0.25
0.8
120
LT1097
50
0.35
1000
14
0.008
0.2
0.7
120
LT1112 (Dual) 60
0.25
1500
14
0.008
0.16
0.75
115
LT1124 (Dual) 70
20
4000
2.7
0.3
4.5
12.5
19
LT1468
75
10
5000
5
0.6
22
90
2.5
LT1469 (Dual) 125
10
2000
5
0.6
22
90
2.5
12
POWER
DISSIPATION
mW
46
11
10.5/Op Amp
69/Op Amp
117
123/Op Amp
1588992fa
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