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 settings)
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 output to 0V regardless of output range.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation 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
Reference Current Constant for All Codes
Voltage-Controlled Offset and Gain Trims
Serial Interface with Readback of All Registers
Clear and Power-On-Reset to 0V Regardless of Output
Range
28-Pin SSOP Package
applicaTions
n
n
n
n
Instrumentation
Medical Devices
Automatic Test Equipment
Process Control and Industrial Automation
Typical applicaTion
18-Bit Voltage Output DAC with Software-Selectable Ranges
REF
5V
1.0
LTC2756 Integral Nonlinearity
0.8
0.6
0V TO 10V RANGE
+
LT1012
INL (LSB)
–
R
IN
SPI WITH
READBACK
4
LTC2756
5V
V
DD
0.1µF
GND
GAIN
ADJUST
GE
ADJ
R
COM
0.4
150pF
0.2
0
–0.2
–0.4
–0.6
REF
R
OFS
R
FB
27pF
I
OUT1
I
OUT2
GND
V
OSADJ
2756 TA01a
–0.8
18-BIT DAC WITH SPAN SELECT
OFFSET
ADJUST
For more information
www.linear.com/LTC2756
+
–
LT1468
V
OUT
–1.0
0
65536
131072
CODE
196608
262143
2756 TA01b
2756fa
1
LTC2756
absoluTe MaxiMuM raTings
(Notes 1, 2)
pin conFiguraTion
TOP VIEW
R
OFS
REF
R
COM
GE
ADJ
R
IN
GND
I
OUT2
GND
CS/LD
1
2
3
4
5
6
7
8
9
28 R
FB
27 R
FB
26 I
OUT1
25 V
OSADJ
24 GND
23
LDAC
22 S2
21 S1
20 S0
19 M-SPAN
18
RFLAG
17
CLR
16 GND
15 GND
I
OUT1
, I
OUT2
to GND................................................±0.3V
R
IN
, R
COM
, REF, R
FB
, R
OFS
, V
OSADJ
,
GE
ADJ
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
LTC2756C ................................................ 0°C to 70°C
LTC2756I .............................................–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
SDI 10
SCK 11
SRO 12
GND 13
V
DD
14
G PACKAGE
28-LEAD PLASTIC SSOP
T
JMAX
= 150°C,
θ
JA
= 95°C/W
orDer inForMaTion
LEAD FREE FINISH
LTC2756BCG#PBF
LTC2756BIG#PBF
LTC2756ACG#PBF
LTC2756AIG#PBF
TAPE AND REEL
LTC2756BCG#TRPBF
LTC2756BIG#TRPBF
LTC2756ACG#TRPBF
LTC2756AIG#TRPBF
http://www.linear.com/product/LTC2756#orderinfo
PART MARKING*
LTC2756G
LTC2756G
LTC2756G
LTC2756G
PACKAGE DESCRIPTION
28-Lead Plastic SSOP
28-Lead Plastic SSOP
28-Lead Plastic SSOP
28-Lead Plastic SSOP
TEMPERATURE RANGE
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/.
Some packages are available in 500 unit reels through
designated sales channels with #TRMPBF suffix.
2
2756fa
For more information
www.linear.com/LTC2756
LTC2756
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
IN
) = 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
LTC2756B
TYP
MAX
MIN
18
18
LTC2756A
TYP
MAX
UNITS
Bits
Bits
Static Performance
±1
±2
±40
±0.25
±24
±0.15
±0.03
±3.2
±1.6
±4
±0.05
±2
±5
±0.25
±0.5
±5
±0.25
±2.5
±0.15
±0.03
±0.05
±0.2
±0.05
±1
±1
±28
±16
±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
IN
) = 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) Multiplying
(Note 11) 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
–108
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
THD
Total Harmonic Distortion
Output Noise Voltage Density
μs
nV•s
nV•s
nV•s
nV•s
MHz
mV
dB
nV/√Hz
2756fa
For more information
www.linear.com/LTC2756
3
LTC2756
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
IN
) = 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
Supply Current, V
DD
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 12)
CONDITIONS
l
l
MIN
2.7
TYP
MAX
5.5
UNITS
V
μA
V
V
0.5
2.4
2
1
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
2756fa
C
LOAD
= 10pF (Note 12)
C
LOAD
= 10pF (Note 12)
50% Duty Cycle (Note 13)
l
l
l
l
l
l
l
l
l
4
For more information
www.linear.com/LTC2756
LTC2756
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 12)
C
LOAD
= 10pF (Note 12)
50% Duty Cycle (Note 13)
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
IN
to R
COM
; feedback resistors
measured from R
COM
to REF
.
Note 5:
DAC input resistance is independent of code.
Note 6:
Parallel combination of the resistances from the specified pin to
I
OUT1
and from the specified pin to I
OUT2
.
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:
REF = 6V
RMS
at 1kHz. 0V to 5V range. DAC code = FS. Output
amplifier = LT1468.
Note 11:
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.
单片机
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
