provides full 18-bit performance (INL and DNL of ±1LSB
maximum) over temperature without any adjustments.
18-bit monotonicity is guaranteed in all performance
grades. This SoftSpan™ DAC operates from a single 3V
to 5V supply and offers six output ranges (up to ±10V)
that can be programmed through the 3-wire SPI serial
interface or pin-strapped for operation in a single range.
Any on-chip register (including DAC output-range set-
tings) can be read for verification in just one instruction
cycle; and if you change register content, the altered
register will be automatically read back during the next
instruction cycle.
Voltage-controlled offset and gain adjustments are also
provided; and the power-on reset circuit and
CLR
pin both
reset the DAC outputs to 0V regardless of output range.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
SoftSpan is a trademark of Linear Technology Corporation. All other trademarks are the property
of their respective owners.
n
n
n
n
n
n
n
n
n
Maximum 18-Bit INL Error: ±1 LSB Over Temperature
Program or Pin-Strap Six Output Ranges:
0V to 5V, 0V to 10V, –2.5V to 7.5V, ±2.5V, ±5V, ±10V
Guaranteed Monotonic Over Temperature
Glitch Impulse 0.4nV
•
s (3V), 2nV
•
s (5V)
18-Bit Settling Time: 2.1µs
2.7V to 5.5V Single Supply Operation
1µA Maximum Supply Current
Voltage-Controlled Offset and Gain Trims
Serial Interface with Readback of All Registers
Clear and Power-On-Reset to 0V Regardless of
Output Range
48-Pin 7mm
×
7mm LQFP Package
applicaTions
n
n
n
n
Instrumentation
Medical Devices
Automatic Test Equipment
Process Control and Industrial Automation
Typical applicaTion
Dual 18-Bit V
OUT
DAC with Software-Selectable Ranges
GAIN A
ADJUST
LTC2758 Integral Nonlinearity
1.0
0.8
0.6
0V TO 10V RANGE
GE
ADJA
R
OFSA
REFA
5V
V
DD
0.1µF
R
FBA
I
OUT1A
DAC A
I
OUT2A
V
OSADJA
R
FBB
I
OUT1B
DAC B
GND
GE
ADJB
R
OFSB
REFB
GAIN B
ADJUST
R
COMB
I
OUT2B
V
OSADJB
R
INB
2758 TA01a
INL (LSB)
V
OUTA
SPI WITH
READBACK
4
LTC2758
OFFSET B ADJUST
LT1012
REFERENCE
5V
For more information
www.linear.com/LTC2758
+
–
–
+
R
COMA
LT1012
REFERENCE
5V
R
INA
27pF
0.4
0.2
0
–0.2
–0.4
–0.6
–0.8
–1.0
V
OUTB
LT1468
0
65536
131072
CODE
196608
262143
2758 TA01b
–
+
LT1468
OFFSET A ADJUST
27pF
+
–
2758fb
1
LTC2758
absoluTe MaxiMuM raTings
(Notes 1, 2)
pin conFiguraTion
TOP VIEW
R
OFSA
R
OFSA
R
FBA
R
FBA
I
OUT1A
V
OSADJA
V
OSADJB
I
OUT1B
R
FBB
R
FBB
R
OFSB
R
OFSB
REF A 1
REF A 2
R
COMA
3
GE
ADJA
4
R
INA
5
R
INA
6
GND 7
I
OUT2AS
8
I
OUT2AF
9
GND 10
CS/LD
11
SDI 12
48
47
46
45
44
43
42
41
40
39
38
37
I
OUT1X
, I
OUT2X
to GND............................................±0.3V
R
INX
, R
COMX
, REFX, R
FBX
, R
OFSX
, V
OSADJX
,
GE
ADJX
to GND ....................................................... ±18V
V
DD
to GND .................................................. –0.3V to 7V
Digital Inputs to GND ................................... –0.3V to 7V
Digital Outputs to GND .....–0.3V to V
DD
+0.3V (max 7V)
Operating Temperature Range
LTC2758C ................................................ 0°C to 70°C
LTC2758I .............................................–40°C to 85°C
Maximum Junction Temperature .......................... 150°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................... 300°C
36
35
34
33
32
31
30
29
28
27
26
25
REF B
REF B
R
COMB
GE
ADJB
R
INB
R
INB
GND
I
OUT2BS
I
OUT2BF
GND
LDAC
S2
orDer inForMaTion
LEAD FREE FINISH
LTC2758BCLX#PBF
LTC2758BILX#PBF
LTC2758ACLX#PBF
LTC2758AILX#PBF
LTC2758LX
LTC2758LX
LTC2758LX
LTC2758LX
http://www.linear.com/product/LTC2758#orderinfo
PACKAGE DESCRIPTION
48-Lead (7mm
×
7mm) Plastic LQFP
48-Lead (7mm
×
7mm) Plastic LQFP
48-Lead (7mm
×
7mm) Plastic LQFP
48-Lead (7mm
×
7mm) Plastic LQFP
TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
PART MARKING*
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
This product is only offered in trays. For more information go to:
http://www.linear.com/packaging/.
Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
SCK 13
SRO 14
GND 15
V
DD
16
GND 17
GND 18
CLR
19
RFLAG
20
DNC 21
M-SPAN 22
S0 23
S1 24
LX PACKAGE
48-LEAD (7mm
×
7mm) PLASTIC LQFP
T
JMAX
= 150°C,
θ
JA
= 53°C/W
2
2758fb
For more information
www.linear.com/LTC2758
LTC2758
elecTrical characTerisTics
SYMBOL
PARAMETER
Resolution
Monotonicity
DNL
INL
GE
BZE
Differential Nonlinearity
Integral Nonlinearity
Gain Error
Gain Error Temperature Coefficient
Bipolar Zero Error
Bipolar Zero Temperature Coefficient
Unipolar Zero-Scale Error
PSR
I
LKG
Power Supply Rejection
I
OUT1
Leakage Current
Unipolar Ranges (Note 3)
V
DD
= 5V, ±10%
V
DD
= 3V, ±10%
T
A
= 25°C
T
MIN
to T
MAX
l
l
l
V
DD
= 5V, V(R
INX
) = 5V unless otherwise specified. The
l
denotes the
specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
CONDITIONS
l
l
l
l
MIN
18
18
LTC2758B
TYP
MAX
MIN
18
18
LTC2758A
TYP
MAX
UNITS
Bits
Bits
Static Performance
±1
±2
±48
±0.25
±36
±0.2
±0.03
±3.2
±1.6
±4
±0.05
±2
±5
±0.2
±0.5
±6
±0.25
±1
±0.2
±0.03
±0.1
±0.3
±0.05
±1
±1
±32
±24
±3.2
±0.8
±2
±2
±5
LSB
LSB
LSB
ppm/°C
LSB
ppm/°C
LSB
LSB/V
LSB/V
nA
nA
All Output Ranges
∆Gain/∆Temp
All Bipolar Ranges
l
l
l
V
DD
= 5V, V(R
INX
) = 5V unless otherwise specified. The
l
denotes specifications that apply over the full operating temperature range,
otherwise specifications are at T
A
= 25°C.
SYMBOL
Analog Pins
Reference Inverting Resistors
R
REF
R
FB
R
OFS
R
VOSADJ
R
GEADJ
C
IOUT1
DAC Input Resistance
Feedback Resistors
Bipolar Offset Resistors
Offset Adjust Resistors
Gain Adjust Resistors
Output Capacitance
Full-Scale
Zero-Scale
Span Code = 0000, 10V Step. To ±0.0004%
FS (Note 7)
V
DD
= 5V (Note 8)
V
DD
= 3V (Note 8)
V
DD
= 5V (Note 9)
V
DD
= 3V (Note 9)
0V to 5V Range,
Code = Full Scale, –3dB Bandwidth
0V to 5V Range, V
REF
= ±10V, 10kHz
Sine Wave
(Note 10)
(Note 11) Multiplying
(Note 12) at I
OUT1
(Note 4)
(Notes 5, 6)
(Note 6)
(Note 6)
l
l
l
l
l
l
PARAMETER
CONDITIONS
MIN
16
8
8
16
1024
2048
TYP
20
10
10
20
1280
2560
90
40
2.1
2
0.4
2.6
0.6
1
0.4
–109
–110
13
MAX
UNITS
kΩ
kΩ
kΩ
kΩ
kΩ
kΩ
pF
Dynamic Performance
Output Settling Time
Glitch Impulse
Digital-to-Analog Glitch Impulse
Reference Multiplying BW
Multiplying Feedthrough Error
Analog Crosstalk
THD
Total Harmonic Distortion
Output Noise Voltage Density
μs
nV•s
nV•s
nV•s
nV•s
MHz
mV
dB
dB
nV/√Hz
2758fb
For more information
www.linear.com/LTC2758
3
LTC2758
elecTrical characTerisTics
SYMBOL
Power Supply
V
DD
I
DD
Digital Inputs
V
IH
V
IL
Digital Input High Voltage
Digital Input Low Voltage
Hysteresis Voltage
I
IN
C
IN
Digital Outputs
V
OH
V
OL
I
OH
= 200µA
I
OL
= 200µA
2.7V ≤ V
DD
≤ 5.5V
2.7V ≤ V
DD
≤ 5.5V
l
l
V
DD
= 5V, V(R
INX
) = 5V unless otherwise specified. The
l
denotes the
specifications which apply over the full operating temperature range, otherwise specifications are at T
A
= 25°C.
PARAMETER
Supply Voltage
V
DD
Supply Current
Digital Inputs = 0V or V
DD
3.3V ≤ V
DD
≤ 5.5V
2.7V ≤ V
DD
< 3.3V
4.5V < V
DD
≤ 5.5V
2.7V ≤ V
DD
≤ 4.5V
V
IN
= GND to V
DD
V
IN
= 0V (Note 13)
CONDITIONS
l
l
MIN
2.7
TYP
MAX
5.5
UNITS
V
μA
V
V
0.5
2.4
2
2
l
l
l
l
0.8
0.6
0.1
±1
6
V
DD
– 0.4
0.4
V
V
V
µA
pF
V
V
Digital Input Current
Digital Input Capacitance
l
l
TiMing characTerisTics
otherwise specifications are at T
A
= 25°C.
PARAMETER
SDI Valid to SCK Set-Up
SDI Valid to SCK Hold
SCK High Time
SCK Low Time
CS/LD
Pulse Width
LSB SCK High to
CS/LD
High
CS/LD
Low to SCK Positive Edge
CS/LD
High to SCK Positive Edge
SRO Propagation Delay
CLR
Pulse Width Low
LDAC
Pulse Width Low
CLR
Low to
RFLAG
Low
CS/LD
High to
RFLAG
High
SCK Frequency
V
DD
= 2.7V to 3.3V
t
1
t
2
t
3
t
4
t
5
t
6
SDI Valid to SCK Set-Up
SDI Valid to SCK Hold
SCK High Time
SCK Low Time
CS/LD
Pulse Width
LSB SCK High to
CS/LD
High
SYMBOL
t
1
t
2
t
3
t
4
t
5
t
6
t
7
t
8
t
9
t
10
t
11
t
12
t
13
V
DD
= 4.5V to 5.5V
The
l
denotes specifications that apply over the full operating temperature range,
CONDITIONS
l
l
l
l
l
l
l
l
MIN
7
7
11
11
9
4
4
4
TYP
MAX
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
C
LOAD
= 10pF
l
l
l
18
36
15
50
40
40
9
9
15
15
12
5
ns
ns
ns
ns
ns
MHz
ns
ns
ns
ns
ns
ns
2758fb
C
LOAD
= 10pF (Note 13)
C
LOAD
= 10pF (Note 13)
50% Duty Cycle (Note 14)
l
l
l
l
(Note 13)
C
L
= 10pF
l
l
l
l
l
4
For more information
www.linear.com/LTC2758
LTC2758
TiMing characTerisTics
otherwise specifications are at T
A
= 25°C.
PARAMETER
CS/LD
Low to SCK Positive Edge
CS/LD
High to SCK Positive Edge
SRO Propagation Delay
CLR
Pulse Width Low
LDAC
Pulse Width Low
CLR
Low to
RFLAG
Low
CS/LD
High to
RFLAG
high
SCK Frequency
C
LOAD
= 10pF (Note 13)
C
LOAD
= 10pF (Note 13)
50% Duty Cycle (Note 14)
C
LOAD
= 10pF
SYMBOL
t
7
t
8
t
9
t
10
t
11
t
12
t
13
The
l
denotes specifications that apply over the full operating temperature range,
CONDITIONS
l
l
l
l
l
l
l
l
MIN
5
5
TYP
MAX
UNITS
ns
ns
26
60
20
70
60
25
ns
ns
ns
ns
ns
MHz
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
Continuous operation above the specified maximum operating
junction temperature may impair device reliability.
Note 3:
Calculation from feedback resistance and I
OUT1
leakage current
specifications; not production tested. In most applications, unipolar zero-
scale error is dominated by contributions from the output amplifier.
Note 4:
Input resistors measured from R
INX
to R
COMX
; feedback resistors
measured from R
COMX
to REFX.
Note 5:
DAC input resistance is independent of code.
Note 6:
Parallel combination of the resistances from the specified pin to
I
OUT1X
and from the specified pin to I
OUT2X
.
Note 7:
Using LT1468 with C
FEEDBACK
= 27pF A ±0.0004% settling time
.
of 1.8µs can be achieved by optimizing the time constant on an individual
basis. See Application Note 120,
1ppm Settling Time Measurement for a
Monolithic 18-Bit DAC.
Note 8:
Measured at the major carry transition, 0V to 5V range. Output
amplifier: LT1468; C
FB
= 50pF.
Note 9:
Full-scale transition; REF = 0V.
Note 10:
Analog Crosstalk is defined as the AC voltage ratio V
OUTB
/V
REFA
,
expressed in dB. REFB is grounded, and DAC B is set to 0V-5V span and
zero-, mid- or full- scale code. V
REFA
is a 3V
RMS
, 1kHz sine wave.
Note 11:
REF = 6V
RMS
at 1kHz. 0V to 5V range. DAC code = FS. Output
amplifier = LT1468.
Note 12:
Calculation from V
n
= √4kTRB, where k = 1.38E-23 J/°K
(Boltzmann constant), R = resistance (Ω), T = temperature (°K), and B =
bandwidth (Hz). 0V to 5V Range; zero-, mid-, or full-scale.
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