LTC2656
Octal 16-/12-Bit Rail-to-Rail
DACs with 10ppm/°C
Max Reference
FEATURES
Precision 10ppm/°C Max Reference
n
Maximum INL Error: ±4LSB at 16 Bits
n
Guaranteed Monotonic over Temperature
n
Selectable Internal or External Reference
n
2.7V to 5.5V Supply Range (LTC2656-L)
n
Integrated Reference Buffers
n
Ultralow Crosstalk Between DACs(<1nV•s)
n
Power-On-Reset to Zero-Scale/Mid-scale
n
Asynchronous LDAC Update Pin
n
Tiny 20-Lead 4mm × 5mm QFN and 20-Lead
Thermally Enhanced TSSOP Packages
n
DESCRIPTION
The LTC
®
2656 is a family of octal 16-/12-bit rail-to-rail
DACs with a precision integrated reference. The DACs have
built-in high performance, rail-to-rail, output buffers and
are guaranteed monotonic. The LTC2656-L has a full-scale
output of 2.5V with the integrated 10ppm/°C reference and
operates from a single 2.7V to 5.5V supply. The LTC2656-H
has a full-scale output of 4.096V with the integrated refer-
ence and operates from a 4.5V to 5.5V supply. Each DAC can
also operate with an external reference, which sets the DAC
full-scale output to two times the external reference voltage.
These DACs communicate via a SPI/MICROWIRE™ com-
patible 4-wire serial interface which operates at clock rates
up to 50MHz. The LTC2656 incorporates a power-on reset
circuit that is controlled by the PORSEL pin. If PORSEL
is tied to GND the DACs reset to zero-scale. If PORSEL is
tied to V
CC
, the DACs reset to mid-scale.
L,
LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 5396245, 6891433.
APPLICATIONS
n
n
n
n
n
Mobile Communications
Process Control and Industrial Automation
Instrumentation
Automatic Test Equipment
Automotive
BLOCK DIAGRAM
REFCOMP
GND
REGISTER
REGISTER
REGISTER
REGISTER
REFLO
V
OUTA
DAC A
REF
REF
INTERNAL REFERENCE
REF
V
CC
DAC H
REF
V
OUTH
4
3
DAC G
REF
V
OUTG
INL (LSB)
2
1
0
–1
–2
–3
–4
128
DAC E
POWER-ON RESET
CONTROL LOGIC
SCK
LDAC
32-BIT SHIFT REGISTER
DECODE
V
OUTE
PORSEL
SDO
SDI
CLR
2656 TA01a
REFIN/OUT
INL vs Code
REGISTER
REGISTER
REGISTER
V
OUTB
DAC B
REF
REGISTER
REGISTER
REGISTER
V
OUTC
DAC C
REF
REGISTER
REGISTER
DAC F
REF
V
OUTF
DAC A
DAC B
DAC C
DAC D
16384
32768
CODE
49152
DAC E
DAC F
DAC G
DAC H
65535
2656 TA01b
REGISTER
REGISTER
REGISTER
V
OUTD
DAC D
CS/LD
REGISTER
2656fa
1
LTC2656
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
Supply Voltage (V
CC
) ................................... –0.3V to 6V
CS/LD,
SCK, SDI,
LDAC, CLR,
REFLO .......... –0.3V to 6V
V
OUTA
to V
OUTH
................. –0.3V to Min(V
CC
+ 0.3V, 6V)
REFIN/OUT, REFCOMP ...... –0.3V to Min(V
CC
+ 0.3V, 6V)
PORSEL, SDO ................... –0.3V to Min(V
CC
+ 0.3V, 6V)
Operating Temperature Range
LTC2656C ................................................ 0°C to 70°C
LTC2656I.............................................. –40°C to 85°C
Maximum Junction Temperature........................... 150°C
Storage Temperature Range....................... –65 to 150°C
Lead Temperature (Soldering, 10 sec)
FE Package ....................................................... 300°C
PIN CONFIGURATION
REFLO
TOP VIEW
REFLO
V
OUTA
V
OUTB
REFCOMP
V
OUTC
V
OUTD
REFIN/OUT
LDAC
CS/LD
1
2
3
4
5
6
7
8
9
21
20 GND
19 V
CC
18 V
OUTH
17 V
OUTG
16 V
OUTF
15 V
OUTE
14 PORSEL
13
CLR
12 SDO
11 SDI
V
OUTB
1
REFCOMP 2
V
OUTC
3
V
OUTD
4
REFIN/OUT 5
LDAC
6
7
CS/LD
8
SCK
9 10
SDI
SDO
21
TOP VIEW
V
OUTA
GND
V
CC
16 V
OUTH
15 V
OUTG
14 V
OUTF
13 V
OUTE
12 PORSEL
11
CLR
20 19 18 17
SCK 10
FE PACKAGE
20-LEAD PLASTIC TSSOP
T
JMAX
= 150°C,
θ
JA
= 38°C/W,
θ
JC
= 10°C/W
EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB
UFD PACKAGE
20-LEAD (4mm
×
5mm) PLASTIC QFN
T
JMAX
= 150°C,
θ
JA
= 43°C/W
EXPOSED PAD (PIN 21) IS GND, MUST BE SOLDERED TO PCB
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2
LTC2656
PRODUCT SELECTOR GUIDE
LTC2656 B
C
UFD -L
16
#TR PBF
LEAD FREE DESIGNATOR
PBF = Lead Free
TAPE AND REEL
TR = Tape and Reel
RESOLUTION
16 = 16-Bit
12 = 12-Bit
FULL-SCALE VOLTAGE, INTERNAL REFERENCE MODE
L = 2.5V
H = 4.096V
PACKAGE TYPE
UFD = 20-Lead (4mm × 5mm) Plastic QFN
FE = 20-Lead Thermally Enhanced TSSOP
TEMPERATURE GRADE
C = Commercial Temperature Range (0°C to 70°C)
I = Industrial Temperature Range (–40°C to 85°C)
ELECTRICAL GRADE (OPTIONAL)
B = ±4LSB Maximum INL (16-Bit)
C = ±12LSB Maximum INL (16-Bit)
PRODUCT PART NUMBER
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/
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3
LTC2656
ORDER INFORMATION
LEAD FREE FINISH
LTC2656BCFE-L16#PBF
LTC2656BIFE-L16#PBF
LTC2656BCUFD-L16#PBF
LTC2656BIUFD-L16#PBF
LTC2656BCFE-H16#PBF
LTC2656BIFE-H16#PBF
LTC2656BCUFD-H16#PBF
LTC2656BIUFD-H16#PBF
LTC2656CCFE-L16#PBF
LTC2656CIFE-L16#PBF
LTC2656CCUFD-L16#PBF
LTC2656CIUFD-L16#PBF
LTC2656CFE-L12#PBF
LTC2656IFE-L12#PBF
LTC2656CUFD-L12#PBF
LTC2656IUFD-L12#PBF
LTC2656CFE-H12#PBF
LTC2656IFE-H12#PBF
LTC2656CUFD-H12#PBF
LTC2656IUFD-H12#PBF
TAPE AND REEL
LTC2656BCFE-L16#TRPBF
LTC2656BIFE-L16#TRPBF
LTC2656BCUFD-L16#TRPBF
LTC2656BIUFD-L16#TRPBF
LTC2656BCFE-H16#TRPBF
LTC2656BIFE-H16#TRPBF
LTC2656BCUFD-H16#TRPBF
LTC2656BIUFD-H16#TRPBF
LTC2656CCFE-L16#TRPBF
LTC2656CIFE-L16#TRPBF
LTC2656CCUFD-L16#TRPBF
LTC2656CIUFD-L16#TRPBF
LTC2656CFE-L12#TRPBF
LTC2656IFE-L12#TRPBF
LTC2656CUFD-L12#TRPBF
LTC2656IUFD-L12#TRPBF
LTC2656CFE-H12#TRPBF
LTC2656IFE-H12#TRPBF
LTC2656CUFD-H12#TRPBF
LTC2656IUFD-H12#TRPBF
PART MARKING* PACKAGE DESCRIPTION
LTC2656FE-L16
LTC2656FE-L16
56L16
56L16
LTC2656FE-H16
LTC2656FE-H16
56H16
56H16
20-Lead Thermally Enhanced TSSOP
20-Lead Thermally Enhanced TSSOP
20-Lead (4mm × 5mm) Plastic QFN
20-Lead (4mm × 5mm) Plastic QFN
20-Lead Thermally Enhanced TSSOP
20-Lead Thermally Enhanced TSSOP
20-Lead (4mm × 5mm) Plastic QFN
20-Lead (4mm × 5mm) Plastic QFN
TEMPERATURE
RANGE
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
0°C to 70°C
–40°C to 85°C
MAXIMUM
INL
±4
±4
±4
±4
±4
±4
±4
±4
±12
±12
±12
±12
±1
±1
±1
±1
±1
±1
±1
±1
LTC2656CFE-L16 20-Lead Thermally Enhanced TSSOP
LTC2656CFE-L16 20-Lead Thermally Enhanced TSSOP
6CL16
6CL16
LTC2656FE-L12
LTC2656FE-L12
56L12
56L12
LTC2656FE-H12
LTC2656FE-H12
56H12
56H12
20-Lead (4mm × 5mm) Plastic QFN
20-Lead (4mm × 5mm) Plastic QFN
20-Lead Thermally Enhanced TSSOP
20-Lead Thermally Enhanced TSSOP
20-Lead (4mm × 5mm) Plastic QFN
20-Lead (4mm × 5mm) Plastic QFN
20-Lead Thermally Enhanced TSSOP
20-Lead Thermally Enhanced TSSOP
20-Lead (4mm × 5mm) Plastic QFN
20-Lead (4mm × 5mm) Plastic QFN
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/
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4
LTC2656
ELECTRICAL CHARACTERISTICS
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
CC
= 2.7V to 5.5V, V
OUT
unloaded unless otherwise specified.
LTC2656B-L16/LTC2656C-L16/LTC2656-L12 (internal reference = 1.25V)
SYMBOL PARAMETER
DC Performance
Resolution
Monotonicity
DNL
INL
Differential Nonlinearity
Integral Nonlinearity (Note 3)
Load Regulation
(Note 3)
(Note 3)
LTC2656B-L16: V
CC
= 5.5V, V
REF
= 2.5V
LTC2656C-L16: V
CC
= 5.5V, V
REF
= 2.5V
l
l
l
l
l
CONDITIONS
LTC2656-L12
MIN TYP MAX
12
12
±0.1
±0.5
±0.5
±1
LTC2656B-L16/
LTC2656C-L16
MIN TYP MAX
16
16
±0.3
±2
±6
0.6
1
1
±1
2
±0.02 ±0.1
1
±1
±4
±12
2
4
3
±2
UNITS
Bits
Bits
LSB
LSB
LSB
LSB/mA
LSB/mA
mV
mV
µV/°C
%FSR
ppm/°C
V
CC
= 5V ±10%, Internal Reference, Mid-Scale,
l
–15mA ≤ I
OUT
≤ 15mA
V
CC
= 3V ±10%, Internal Reference, Mid-Scale,
l
–7.5mA ≤ I
OUT
≤ 7.5mA
0.04 0.125
0.06
1
±1
2
0.25
3
±2
ZSE
V
OS
GE
Zero-Scale Error
Offset Error
V
OS
Temperature Coefficient
Gain Error
Gain Temperature Coefficient
V
REF
= 1.25V (Note 4)
l
l
l
±0.02 ±0.1
1
SYMBOL PARAMETER
V
OUT
PSR
R
OUT
DAC Output Span
Power Supply Rejection
DC Output Impedance
CONDITIONS
Internal Reference
External Reference = V
EXTREF
V
CC
±10%
V
CC
= 5V ±10%, Internal Reference, Mid-Scale,
–15mA ≤ I
OUT
≤ 15mA
V
CC
= 3V ±10%, Internal Reference, Mid-Scale,
–7.5mA ≤ I
OUT
≤ 7.5mA
l
l
MIN
TYP
0 to 2.5
0 to 2 • V
EXTREF
–80
0.04
0.04
±1.5
±2
±1
MAX
UNITS
V
V
dB
0.15
0.15
Ω
Ω
µV
µV/mA
µV
DC Crosstalk (Note 5)
Due to Full-Scale Output Change
Due to Load Current Change
Due to Powering Down (per Channel)
V
CC
= 5.5V, V
EXTREF
= 2.75V
Code: Zero-Scale, Forcing Output to V
CC
Code: Full-Scale, Forcing Output to GND
V
CC
= 2.7V, V
EXTREF
= 1.35V
Code: Zero-Scale, Forcing Output to V
CC
Code: Full-Scale, Forcing Output to GND
l
l
l
l
I
SC
Short-Circuit Output Current
(Note 6)
20
20
10
10
1.248
1.25
±2
±2
–80
65
65
40
40
1.252
±10
mA
mA
mA
mA
V
ppm/°C
ppm/°C
dB
mA
µA
mV/mA
nV/√Hz
2656fa
Reference
Reference Output Voltage
Reference Temperature Coefficient
Reference Line Regulation
Reference Short-Circuit Current
Reference Load Regulation
Reference Output Voltage Noise
Density
C-Grade (Note 7)
I-Grade (Note 7)
V
CC
±10%
V
CC
= 5.5V, Forcing Output to GND
V
CC
= 3V ±10% or 5V ±10%, I
OUT
= 100µA
Sourcing
C
REFCOMP
= C
REFIN/OUT
= 0.1µF at f = 1kHz
l
l
3
60
40
30
5
200
REFCOMP Pin Short-Circuit Current V
CC
= 5.5V, Forcing Output to GND
5
Microcontroller MCU
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