LTC1599 Linear Technology, LTC1599 Datasheet - Page 10

• Manufacturer Part Number: LTC1599
• Description: 16-Bit Byte Wide/ Low Glitch Multiplying DAC with 4-Quadrant Resistors
• Manufacturer: Linear Technology

APPLICATIONS
LTC1599
configured in unipolar or bipolar modes of operation
(Figures 1 and 3). These are the changes the op amp can
cause to the INL, DNL, unipolar offset, unipolar gain error,
bipolar zero and bipolar gain error. Table 4 contains a
partial list of LTC precision op amps recommended for use
with the LTC1599. The two sets of easy-to-use design
equations simplify the selection of op amps to meet the
system’s specified error budget. Select the amplifier from
Table 4 and insert the specified op amp parameters in
either Table 2 or Table 3. Add up all the errors for each
category to determine the effect the op amp has on the
accuracy of the LTC1599. Arithmetic summation gives an
(unlikely) worst-case effect. RMS summation produces a
more realistic effect.
Op amp offset will contribute mostly to output offset and
gain error and has minimal effect on INL and DNL. For the
LTC1599, a 500 V op amp offset will cause about 0.55LSB
Table 2. Easy-to-Use Equations Determine Op Amp Effects on DAC Accuracy in Unipolar Applications
OP AMP
V
I
A
Table 4. Partial List of LTC Precision Amplifiers Recommended for Use with the LTC1599, with Relevant Specifications
AMPLIFIER
LT1001
LT1097
LT1112 (Dual)
LT1124 (Dual)
LT1468
10
Table 3. Easy-to-Use Equations Determine Op Amp Effects on DAC Accuracy in Bipolar Applications
OP AMP
V
I
A
V
I
A
B
B1
B2
OS
VOL
OS1
VOL1
OS2
VOL2
(nA)
(nA)
(nA)
(mV)
(V/V)
(mV)
(mV)
I
B1
V
I
B
OS1
V
• 0.00055 • (10V/V
• 0.00055 • (10V/V
V
OS
25
50
60
70
75
OS
V
• 1.2 • (10V/V
• 1.2 • (10V/V
INL (LSB)
10k/A
INL (LSB)
U
10k/A
0
0
0
VOL
VOL
0.35
0.25
INFORMATION
nA
10
20
I
2
U
B
REF
REF
REF
REF
)
)
)
)
V/mV
1000
1500
4000
5000
A
800
W
OL
I
B1
I
V
B
V
OS1
• 0.00015 • (10V/V
• 0.00015 • (10V/V
OS
• 0.3 • (10V/V
• 0.3 • (10V/V
DNL (LSB)
VOLTAGE
DNL (LSB)
3k/A
nV/ Hz
NOISE
3k/A
2.7
10
14
14
5
0
0
0
U
VOL1
VOL
Amplifier Specifications
REF
REF
REF
REF
CURRENT
)
)
pA/ Hz
NOISE
0.008
0.008
)
0.12
)
0.3
0.6
INL degradation and 0.15LSB DNL degradation with a 10V
full-scale range (20V range in bipolar). For the LTC1599
configured in the unipolar mode, the same 500 V op amp
offset will cause a 3.3LSB zero-scale error and a 3.45LSB
gain error with a 10V full-scale range.
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 V
over temperature. Then, plug these numbers in the V
and I
temperature induced effects.
For applications where fast settling time is important,
Application Note 74, entitled “ Component and Measure-
ment Advances Ensure 16-Bit DAC Settling Time ,” offers
a thorough discussion of 16-bit DAC settling time and op
amp selection.
BIPOLAR ZERO ERROR (LSB)
UNIPOLAR OFFSET (LSB)
I
V
B
I
I
V
V
B1
B2
B
OS
OS1
OS2
• 0.065 • (10V/V
SLEW
RATE
V/ s
0.25
0.16
equations from Table 2 or Table 3 and calculate the
• 0.065 • (10V/V
• 0.065 • (10V/V
0.2
4.5
22
• 6.6 • (10V/V
• 9.9 • (10V/V
• 6.7 • (10V/V
65k/A
0
0
VOL2
GAIN BANDWIDTH
PRODUCT
REF
REF
REF
REF
REF
REF
MHz
0.75
12.5
)
0.8
0.7
)
90
)
)
)
)
UNIPOLAR GAIN ERROR (LSB)
BIPOLAR GAIN ERROR (LSB)
with LTC1599
V
V
t
OS
V
I
SETTLING
OS2
B2
OS1
120
120
115
2.5
• 6.9 • (10V/V
19
• 0.13 • (10V/V
131k/A
s
• 13.2 • (10V/V
• 6.9 • (10V/V
196k/A
131k/A
0
0
VOL
VOL1
VOL2
DISSIPATION
10.5/Op Amp
REF
69/Op Amp
OS
REF
POWER
REF
)
REF
mW
117
46
11
)
)
and I
)
OS
B