LTC1654
Dual 14-Bit Rail-to-Rail DAC
in 16-Lead SSOP Package
FEATURES
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DESCRIPTIO
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14-Bit Monotonic Over Temperature
Individually Programmable Speed/Power:
3µs Settling Time at 930µA
8.5µs Settling Time at 540µA
3V to 5V Single Supply Operation
Maximum Update Rate: 0.9MHz
Buffered True Rail-to-Rail Voltage Outputs
User Selectable Gain
Power-On Reset and Clear Function
Schmitt Trigger On Clock Input Allows Direct
Optocoupler Interface
Smallest Dual 14-Bit DAC: 16-Lead Narrow
SSOP Package
The LTC
®
1654 is a dual, rail-to-rail voltage output, 14-bit
digital-to-analog converter (DAC). It is available in a
16-lead narrow SSOP package, making it the smallest dual
14-bit DAC available. It includes output buffer amplifiers
and a flexible serial interface.
The LTC1654 has REFHI pins for each DAC that can be
driven up to V
CC
. The output will swing from 0V to V
CC
in
a gain of 1 configuration or V
CC
/2 in a gain of 1/2 configu-
ration. It operates from a single 2.7V to 5.5V supply.
The LTC1654 has two programmable speeds: a FAST and
SLOW mode with
±1LSB
settling times of 3µs or 8.5µs
respectively and supply currents of 930µA and 540µA in
the two modes. The LTC1654 also has shutdown capabil-
ity, power-on reset and a clear function to 0V.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 5396245.
APPLICATIO S
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Digital Calibration
Industrial Process Control
Automatic Test Equipment
Offset/Gain Adjustment
Multiplying DAC
BLOCK DIAGRA
CS/LD
SCK
CONTROL
LOGIC
SDI
INPUT
LATCH
DAC
REGISTER
DAC B
+
V
OUT B
–
32-BIT
SHIFT
REGISTER
X
1
/X
1/2
B
REFHI A
INPUT
LATCH
DAC
REGISTER
DAC A
+
V
OUT A
SDO
POWER-ON
RESET
REFLO B
REFLO A
–
X
1
/X
1/2
A
1654 BD
CLR
U
REFHI B
1654fb
W
U
1
LTC1654
ABSOLUTE
(Note 1)
AXI U
RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
X
1
/X
1/2
B
CLR
SCK
SDI
CS/LD
DGND
SDO
X
1
/X
1/2
A
1
2
3
4
5
6
7
8
16 V
CC
15 V
OUT B
14 REFHI B
13 REFLO B
12 AGND
11 REFLO A
10 REFHI A
9
V
OUT A
V
CC
to GND .............................................. – 0.5V to 7.5V
TTL Input Voltage, REFHI,
REFLO, X
1
/X
1/2
........................................ – 0.5V to 7.5V
V
OUT
, SDO .................................. – 0.5V to (V
CC
+ 0.5V)
Operating Temperature Range
LTC1654C ............................................. 0°C to 70°C
LTC1654I ........................................ – 40°C to 85°C
Maximum Junction Temperature .......................... 125°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
ORDER PART
NUMBER
LTC1654CGN
LTC1654IGN
GN PART MARKING
1654
1654I
GN PACKAGE
16-LEAD PLASTIC SSOP
T
JMAX
= 125°C,
θ
JA
= 110°C/W
Order Options
Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking:
http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
The
●
denotes specifications which apply over the full operating tempera-
ture range, otherwise specifications are at T
A
= 25°C. Unless otherwise noted, V
CC
= 2.7V to 5.5V, V
OUT A
, V
OUT B
unloaded, REFHI A,
REFHI B = 4.096V (V
CC
= 5V), REFHI A, REFHI B = 2.048V (V
CC
= 2.7V), REFLO = 0V, X
1
/X
1/2
= 0V.
SYMBOL
DAC
n
DNL
INL
ZSE
V
OS
V
OS
TC
PARAMETER
Resolution
Monotonicity
Differential Nonlinearity
Integral Nonlinearity
Zero Scale Error
Offset Error
Offset Error Tempco
Gain Error
Gain Error Drift
Power Supply
V
CC
I
CC
Positive Supply Voltage
Supply Current (SLOW/FAST)
For Specified Performance
2.7V
≤
V
CC
≤
5.5V (Note 5) SLOW
2.7V
≤
V
CC
≤
5.5V (Note 5) FAST
2.7V
≤
V
CC
≤
3.3V (Note 5) SLOW
2.7V
≤
V
CC
≤
3.3V (Note 5) FAST
In Shutdown (Note 5)
V
OUT
Shorted to GND
V
OUT
Shorted to V
CC
Input Code = 0
REFHIA, REFHIB = 4.096V (V
CC
= 5V
±10%)
REFHIA, REFHIB = 2.048V (V
CC
= 3V
±10%)
Input Code = 16383
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ELECTRICAL CHARACTERISTICS
CONDITIONS
MIN
●
●
TYP
MAX
UNITS
Bits
Bits
14
14
±0.3
±1.2
0
±1
±4
6.5
9.0
±6.5
±9.0
±15
±24
5
2.7
540
930
350
680
3
70
80
40
5.5
850
1400
500
1000
10
120
120
200
2.5
Guaranteed Monotonic (Note 2)
Integral Nonlinearity (Note 2)
0°C
≤
T
A
≤
70°C
– 40°C
≤
T
A
≤
85°C
0°C
≤
T
A
≤
70°C (Note 3)
– 40°C
≤
T
A
≤
85°C (Note 3)
●
●
●
●
●
●
ppm/°C
V
µA
µA
µA
µA
µA
mA
mA
Ω
mV/V
Op Amp DC Performance
Short-Circuit Current Low
Short-Circuit Current High
Output Impedance to GND
PSR
Power Supply Rejection
2
U
LSB
LSB
mV
mV
mV
mV
µV/°C
LSB
1654fb
W
U
U
W W
W
LTC1654
ELECTRICAL CHARACTERISTICS
SYMBOL
PARAMETER
Voltage Output Slew Rate
Voltage Output Settling Time
Digital Feedthrough
Midscale Glitch Impulse
Output Noise Voltage Density
Digital I/O
V
IH
V
IL
V
OH
V
OL
V
IH
V
IL
V
OH
V
OL
I
LEAK
C
IN
Digital Input High Voltage
Digital Input Low Voltage
Digital Output High Voltage
Digital Output Low Voltage
Digital Input High Voltage
Digital Input Low Voltage
Digital Output High Voltage
Digital Output Low Voltage
Digital Input Leakage
Digital Input Capacitance
Reference Input Resistance
Reference Input Range
Reference Input Current
Switching Characteristics (V
CC
= 4.5V to 5.5V)
t
1
t
2
t
3
t
4
t
5
t
6
t
7
t
8
t
9
t
10
t
1
t
2
t
3
t
4
t
5
t
6
t
7
SDI Valid to SCK Setup
SDI Valid to SCK Hold
SCK High Time
SCK Low Time
CS/LD Pulse Width
LSB SCK to CS/LD
CS/LD Low to SCK
SD0 Output Delay
SCK Low to CS/LD Low
CLR Pulse Width
SDI Valid to SCK Setup
SDI Valid to SCK Hold
SCK High Time
SCK Low Time
CS/LD Pulse Width
LSB SCK to CS/LD
CS/LD Low to SCK
(Note 6)
(Note 6)
(Note 6)
(Note 6)
(Note 6)
(Note 6)
(Note 6)
(Note 6)
(Note 6)
(Note 6)
(Note 6)
(Note 6)
V
CC
= 5V
V
CC
= 5V
CONDITIONS
AC Performance
The
●
denotes specifications which apply over the full operating tempera-
ture range, otherwise specifications are at T
A
= 25°C. Unless otherwise noted, V
CC
= 2.7V to 5.5V, V
OUT A
, V
OUT B
unloaded, REFHI A,
REFHI B = 4.096V (V
CC
= 5V), REFHI A, REFHI B = 2.048V (V
CC
= 2.7V), REFLO = 0V, X
1
/X
1/2
= 0V.
MIN
●
●
TYP
0.9
3.8
8.5
3.0
1
20
170
150
MAX
UNITS
V/µs
V/µs
µs
µs
nV•s
nV•s
nV/√Hz
nV/√Hz
V
(Note 8) SLOW
(Note 8) FAST
(Note 4) to
±1LSB,
SLOW
(Note 4) to
±1LSB,
FAST
(Note 7)
DAC Switch Between 8000 and 7FFF
at 10kHz, SLOW
at 10kHz, FAST
0.20
1.25
●
●
●
●
●
●
●
●
●
2.4
0.8
V
CC
– 0.4
0.4
2.4
0.8
V
CC
– 0.4
0.4
±10
10
V
V
V
V
V
V
V
µA
pF
kΩ
V
CC
= 5V, I
OUT
= – 1mA, D
OUT
Only
V
CC
= 5V, I
OUT
= 1mA, D
OUT
Only
V
CC
= 3V
V
CC
= 3V
V
CC
= 3V, I
OUT
= – 1mA, D
OUT
Only
V
CC
= 3V, I
OUT
= 1mA, D
OUT
Only
V
IN
= GND to V
CC
(Note 6)
REFHI to REFLO
(Note 6)
In Shutdown
Reference Input
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
●
30
0
60
V
CC
1
V
µA
ns
ns
ns
ns
ns
ns
ns
30
0
15
15
15
10
10
5
10
30
45
0
20
20
20
15
15
100
C
LOAD
= 100pF
(Note 6)
(Note 6)
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
1654fb
Switching Characteristics (V
CC
= 2.7V to 5.5V)
3
LTC1654
The
●
denotes specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. Unless otherwise noted, V
CC
= 2.7V to 5.5V, V
OUT A
, V
OUT B
unloaded,
REFHI A, REFHI B = 4.096V (V
CC
= 5V), REFHI A, REFHI B = 2.048V (V
CC
= 2.7V), REFLO = 0V, X
1
/X
1/2
= 0V.
SYMBOL
t
8
t
9
t
10
PARAMETER
SDO Output Delay
SCK Low to CS/LD Low
CLR Pulse Width
CONDITIONS
C
LOAD
= 100pF
(Note 6)
(Note 6)
●
●
●
ELECTRICAL CHARACTERISTICS
MIN
5
15
45
TYP
MAX
150
UNITS
ns
ns
ns
Switching Characteristics (V
CC
= 2.7V to 5.5V)
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
Nonlinearity is defined from low code k
L
to code 16383. See
Applications Information (page 11).
Note 3:
Offset error is measured at low code k
L
. See Applications
Information (page 11).
Note 4:
DAC switched between code 2 k
L
and code 16383. See
Applications Information (page 11) for definition of low code k
L
.
Note 5:
Digital inputs at 0V or V
CC
.
Note 6:
Guaranteed by design.
Note 7:
CS/LD = 0, V
OUT
= 4.096V and data is being clocked in.
Note 8:
100pF load capacitor.
TYPICAL PERFOR A CE CHARACTERISTICS
Integral Nonlinearity (INL)
vs Input Code
2.0
1.5
1.0
DNL (LSB)
INL (LSB)
2.0
1.5
0.5
0
–0.5
–1.0
–1.5
–2.0
0
8192
INPUT CODE
1654 G01
0.5
0
–0.5
–1.0
–1.5
–2.0
OFFSET ERROR (mV)
0
8192
INPUT CODE
1654 G02
Gain Error vs Temperature
5.0
OUTPUT PULL-DOWN VOLTAGE (V)
2.5
GAIN ERROR (LSB)
V
CC
– V
OUT
(V)
0
–2.5
–5.0
–55
–25
65
TEMPERATURE (°C)
5
35
4
U W
95
1654 G04
Differential Nonlinearity (DNL)
vs Input Code
2.50
Offset vs Temperature
1.0
1.25
0
–1.25
16383
16383
–2.50
–55
–25
65
TEMPERATURE (°C)
5
35
95
125
1654 G03
Minimum Output Voltage
vs Load Current (Output Sinking)
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
125
0
0
T
A
= –55°C
T
A
= 125°C
T
A
= 25°C
Minimum Supply Headroom vs
Load Current (Output Sourcing)
1.0
CODE: ALL 1s
0.9 V
REFHI
= 4.096V
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
15
CODE: ALL ZEROS
T
A
= 125°C
T
A
= 25°C
T
A
= –55°C
10
5
OUTPUT SINK CURRENT (mA)
0
10
5
LOAD CURRENT (mA)
15
1645 G06
1645 G05
1654fb
LTC1654
TYPICAL PERFOR A CE CHARACTERISTICS
Supply Current
vs Logic Input Voltage
3.0
SUPPLY CURRENT (mA)
1.5
0
0
1
3
4
2
LOGIC INPUT VOLTAGE (V)
Midscale Glitch—Fast Mode
V
OUT
10mV/DIV
CS/LD
2V/DIV
TIME (1µs/DIV)
U W
Large-Signal Settling—Fast Mode
Large-Signal Settling—Slow Mode
V
OUT
1V/DIV
V
OUT
1V/DIV
CS/LD
2V/DIV
CS/LD
2V/DIV
5
1654 G07
TIME (2µs/DIV)
1654 G08
TIME (2µs/DIV)
1654 G09
Midscale Glitch—Slow Mode
V
OUT
Glitch at Power-Up
V
CC
0.5V/DIV
V
OUT
10mV/DIV
CS/LD
2V/DIV
V
OUT
50mV/DIV
1654 G10
TIME (1µs/DIV)
1654 G11
TIME (50ms/DIV)
1654 G12
1654fb
5
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