FEATURES
s
s
s
s
s
s
LTC1450/LTC1450L
Parallel Input, 12-Bit
Rail-to-Rail Micropower
DACs in SSOP
DESCRIPTION
The LTC
®
1450/LTC1450L are complete single supply, rail-
to-rail voltage output, 12-bit digital-to-analog converters
(DACs) in a 24-pin SSOP or PDIP package. They include an
output buffer amplifier, reference and a double buffered
parallel digital interface.
The LTC1450 operates from a 4.5V to 5.5V supply. The
output can be pin strapped for 4.095V or 2.048V full-scale.
It has a 2.048V internal reference.
The LTC1450L operates from a 2.7V to 5.5V supply. The
output can be pin strapped for 2.5V or 1.22V full-scale. It
has a 1.22V internal reference.
The LTC1450/LTC1450L offer true stand-alone perfor-
mance. In addition, the reference output, high and low
reference inputs and gain setting resistor are brought to
pins for maximum flexibility.
, LTC and LT are registered trademarks of Linear Technology Corporation.
s
s
s
s
s
Guaranteed Monotonic
Buffered True Rail-to-Rail Voltage Output
12-Bit Resolution
3V Operation (LTC1450L) I
CC
: 250µA Typ
5V Operation (LTC1450) I
CC
: 400µA Typ
Parallel 12-Bit or 8 + 4-Bit Double Buffered
Digital Input
Internal Reference
Output Buffer Configurable to Gain of 1 or 2
Configurable as a Multiplying DAC
Internal Power-On Reset
Maximum DNL Error: 0.5LSB
APPLICATIONS
s
s
s
s
s
s
Digital Calibration
Industrial Process Control
Automatic Test Equipment
Arbitrary Function Generators
Battery-Powered Data Conversion Products
Feedback Control Loops and Gain Control
TYPICAL APPLICATION
LTC1450: 5V
LTC1450L: 3V TO 5V
REFOUT
UPPER
4-BIT
INPUT
LATCH
REFERENCE
LTC1450: 2.048V
LTC1450L: 1.22V
12-BIT
DAC
LATCH
REFHI
V
CC
D11 (MSB)
D8
D7
DATA IN FROM
MICROPROCESSOR
DATA BUS
12-BIT
DAC
+
–
V
OUT
DNL ERROR (LSB)
LOWER
8-BIT
INPUT
LATCH
D0 (LSB)
CSMSB
FROM
MICROPROCESSOR
DECODE LOGIC
WR
CSLSB
LDAC
FROM
SYSTEM RESET
CLR
LTC1450:
0V TO 4.095V
LTC1450L:
0V TO 2.5V
POWER-ON
RESET
GND
REFLO
X1/X2
LTC1450
LTC1450L
1450/50L TA01
U
U
U
Differential Nonlinearity
vs Input Code
0.5
0.0
–0.5
0
512 1024 1536 2048 2560 3072 3584 4095
CODE
1450/50L TA02
1
LTC1450/LTC1450L
ABSOLUTE
MAXIMUM
RATINGS
V
CC
to GND .............................................. – 0.5V to 7.5V
Logic Inputs to GND ................................ – 0.5V to 7.5V
V
OUT
.............................................. – 0.5V to V
CC
+ 0.5V
REFOUT, REFLO, REFHI, X1/X2 ..... – 0.5V to V
CC
+ 0.5V
Maximum Junction Temperature .......................... 125°C
Operating Temperature Range
Commercial ........................................... 0°C to 70°C
Industrial ......................................... – 40°C to 85°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
PACKAGE/ORDER INFORMATION
TOP VIEW
WR
CSLSB
CSMSB
(LSB) D0
D1
D2
D3
D4
D5
1
2
3
4
5
6
7
8
9
24 LDAC
23 CLR
22 X1/X2
21 V
OUT
20 V
CC
19 REFOUT
18 REFHI
17 REFLO
16 GND
15 D11(MSB)
14 D10
13 D9
N PACKAGE
24-LEAD PLASTIC PDIP
ORDER PART
NUMBER
LTC1450CG
LTC1450CN
LTC1450IG
LTC1450IN
LTC1450LCG
LTC1450LCN
LTC1450LIG
LTC1450LIN
D6 10
D7 11
D8 12
G PACKAGE
24-LEAD PLASTIC SSOP
T
JMAX
= 125°C,
θ
JA
= 95°C/ W (G)
T
JMAX
= 125°C,
θ
JA
= 58°C/ W (N)
Consult factory for Military grade parts.
V
CC
= 4.5V to 5.5V (LTC1450), 2.7V to 5.5V (LTC1450L), V
OUT
unloaded,
REFOUT = REFHI, REFLO = GND = X1/X2, T
A
= T
MIN
to T
MAX
, unless otherwise noted.
SYMBOL PARAMETER
DAC
Resolution
DNL
Differential Nonlinearity
INL
Integral Nonlinearity
V
OS
V
OS
TC
V
FS
Offset Error
Offset Error Temperature Coefficient
Full-Scale Voltage
CONDITIONS
q
ELECTRICAL CHARACTERISTICS
MIN
12
TYP
MAX
UNITS
Bits
LSB
LSB
LSB
mV
mV
µV/°C
V
V
V
V
V
V
LSB/°C
LSB/°C
LSB/°C
V
V
LSB/°C
LSB/V
LSB
LSB
mA
Guaranteed Monotonic (Note 1)
T
A
= 25°C
(Note 1)
T
A
= 25°C
q
q
q
±0.5
±3.5
±4.0
±12
±18
4.065
4.045
4.075
2.470
2.460
2.480
±15
4.095
4.095
4.095
2.500
2.500
2.500
±0.10
±0.02
±0.10
1.220
2.048
±0.08
0.7
0.6
0.2
4.125
4.145
4.115
2.530
2.540
2.520
V
FS
TC
Full-Scale Voltage Temperature Coefficient
Using Internal Reference, LTC1450, T
A
= 25°C
Using Internal Reference, LTC1450
External 2.048V Reference, LTC1450
Using Internal Reference, LTC1450L, T
A
= 25°C
Using Internal Reference, LTC1450L
External 1.22V Reference, LTC1450L
Using Internal Reference, LTC1450
Using External Reference, LTC1450/LTC1450L
Using Internal Reference, LTC1450L
LTC1450L
LTC1450
q
q
q
q
Reference Output (REFOUT)
Reference Output Voltage
Reference Output Temperature Coefficient
Reference Line Regulation
Reference Load Regulation
Short-Circuit Current
q
q
q
1.195
2.008
1.245
2.088
±2
±
3.0
±1.5
80
0
≤
I
OUT
≤
100µA,
LTC1450L
LTC1450
REFOUT Shorted to GND
q
q
q
2
U
W
U
U
W W
W
LTC1450/LTC1450L
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER
Reference Input (REFLO = GND)
REFHI Input Range
REFHI Input Resistance
REFHI Input Capacitance
Power Supply
Positive Supply Voltage
V
CC
I
CC
Supply Current
V
CC
= 4.5V to 5.5V (LTC1450), 2.7V to 5.5V (LTC1450L), V
OUT
unloaded,
REFOUT = REFHI, REFLO = GND = X1/X2, T
A
= T
MIN
to T
MAX
, unless otherwise noted.
CONDITIONS
V
REFHI
≤
V
CC
– 1.5V
q
q
MIN
TYP
MAX
V
CC
/2
30
UNITS
V
kΩ
pF
V
V
µA
µA
mA
mA
Ω
V/µs
µs
(nV)(s)
dB
dB
V
V
V
V
V
µA
pF
8
18
15
For Specified Performance, LTC1450L
LTC1450
4.5V
≤
V
CC
≤
5.5V (Note 4) LTC1450
2.7V
≤
V
CC
≤
5.5V (Note 4) LTC1450L
V
OUT
Shorted to GND
V
OUT
Shorted to V
CC
Input Code = 0
(Note 2)
(Notes 2, 3) to
±0.5LSB
LDAC = 1
REFHI = 1kHz, 2V
P–P
REFHI = 1kHz, 2V
P–P
(Code: All 1’s)
V
CC
= 3V, LTC1450L
V
CC
= 5V, LTC1450
V
CC
= 3V, LTC1450L
V
CC
= 5V, LTC1450
LTC1450L
V
CC
= 5V, V
IN
= GND to V
CC
Guaranteed by Design. Not Subject to Test
q
q
q
q
q
q
q
q
2.7
4.5
300
150
400
250
5.5
5.5
620
500
100
120
120
Op Amp DC Performance
Short-Circuit Current Low
Short-Circuit Current High
Output Impedance to GND
AC Performance
Voltage Output Slew Rate
Voltage Output Settling Time
Digital Feedthrough
AC Feedthrough
SINAD
Signal-to-Noise + Distortion
Digital Inputs
V
IH
Digital Input High Voltage
V
IL
V
LTH
I
LEAK
C
IN
Digital Input Low Voltage
Logic Threshold Voltage
Digital Input Leakage
Digital Input Capacitance
40
0.5
1.0
14
5
– 95
85
q
q
q
q
2.2
2.4
0.8
0.8
V
CC
/2
– 10
10
10
q
q
3
LTC1450/LTC1450L
ELECTRICAL CHARACTERISTICS
V
CC
= 4.5V to 5.5V (LTC1450), V
CC
= 2.7V to 3.6V (LTC1450L), T
A
= T
MIN
to T
MAX
, unless otherwise noted.
SYMBOL PARAMETER
Switching Characteristics (Note 5)
t
CS
t
WR
t
CWS
t
CWH
t
DWS
CS (MSB or LSB) Pulse Width
WR Pulse Width
CS to WR Setup
CS to WR Hold
Data Valid to WR Setup
V
CC
= 4.5V to 5.5V (LTC1450)
V
CC
= 2.7V to 3.6V (LTC1450L)
V
CC
= 5V (LTC1450L)
V
CC
= 4.5V to 5.5V (LTC1450)
V
CC
= 2.7V to 3.6V (LTC1450L)
V
CC
= 5V (LTC1450L)
q
q
q
q
q
q
q
q
q
q
CONDITIONS
MIN
40
40
0
0
40
40
0
0
40
40
TYP
MAX
UNITS
ns
ns
ns
ns
15
15
10
– 10
– 10
–5
ns
ns
ns
ns
ns
ns
ns
ns
t
DWH
Data Valid to WR Hold
t
LDAC
t
CLR
LDAC Pulse Width
CLR Pulse Width
The
q
denotes specifications which apply over the full operating
temperature range.
Note 1:
Nonlinearity is defined from the first code that is greater than or
equal to the maximum offset specification to code 4095 (full-scale).
Note 2:
Load is 5kΩ in parallel with 100pF.
Note 3:
DAC switched all 1’s and the code corresponding to V
OS(MAX)
for
the part.
Note 4:
Digital inputs at 0V or V
CC
.
Note 5:
Digital inputs swing 10% to 90% of V
CC
, t
r
= t
f
= 5ns and timing
measurements are from V
CC
/2.
TYPICAL PERFORMANCE CHARACTERISTICS
Minimum Supply Voltage
vs Load Current
5.8
LTC1450 MINIMUM SUPPLY VOLTAGE (V)
5.6
5.4
5.2
5.0
4.8
4.6
4.4
4.2
∆V
OUT
< 1LSB
LTC1450
LTC1450L
3.6
3.4
3.2
3.0
2.8
2.6
0.1
1
10
LOAD CURRENT (mA)
2.4
100
1450/50L G01
420
410
400
390
380
370
360
350
– 55 – 35 –15
V
CC
= 5.5V
V
CC
= 5V
V
CC
= 4.5V
SUPPLY CURRENT (mA)
SUPPLY CURRENT (µA)
4.0
0.01
4
U W
LTC1450 Supply Current
vs Temperature
4.2
Supply Current
vs Logic Input Voltage
8
7
6
LTC1450
5
LTC1450L
4
3
2
1
V
CC
= 5V
ALL LOGIC INPUTS
TIED TOGETHER
450
LTC1450L MINIMUM SUPPLY VOLTAGE (V)
4.0
3.8
440
430
5 25 45 65 85 105 125
TEMPERATURE (°C)
1450/50L G02
0
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
LOGIC INPUT VOLTAGE (V)
1450/50L G03
LTC1450/LTC1450L
TYPICAL PERFORMANCE CHARACTERISTICS
LTC1450L Supply Current
vs Logic Input Voltage
1600
1400
SUPPLY CURRENT (µA)
1200
3.5
OUTPUT SWING (V)
FULL SCALE
R
L
TIED TO GND
OUTPUT PULL-DOWN VOLTAGE (mV)
V
CC
= 3V
ALL LOGIC INPUTS
TIED TOGETHER
1000
800
600
400
200
0
0
0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3.0
LOGIC INPUT VOLTAGE (V)
1450/50L G04
LTC1450 Output Offset Voltage
vs Temperature
5.0
4.5
OUTPUT OFFSET VOLTAGE (mV)
4.0
DNL ERROR (LSB)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
– 55 –35 –15
0
ERROR (LSB)
5 25 45 65 85 105 125
TEMPERATURE (°C)
1450/50L G07
Power Supply Rejection
vs Frequency
TOTAL HARMONIC DISTORTION + NOISE (dB)
90
80
70
60
PSRR (dB)
CODE = FFF
H
50
40
30
20
10
0
1
10
1k
100
FREQUENCY (Hz)
10k
10M
V
OUT
REFOUT
–70
–80
–90
–100
100
1k
10k
FREQUENCY (Hz)
100k
1450/50L G11
1mV/DIV
U W
1450/50L G10
LTC1450 Output Swing
vs Load Resistance
4.5
4.0
1000
LTC1450 Pull-Down Voltage vs
Output Sink Current Capability
100
125°C
3.0
2.5
2.0
1.5
1.0
0.5
0
10
100
1k
LOAD RESISTANCE (Ω)
10k
1450/50L G05
V
CC
= 5V
25°C
10
–55°C
1
ZERO SCALE
R
L
TIED TO V
CC
0.1
0.0001 0.001 0.01
0.1
1
10
OUTPUT SINK CURRENT (mA)
100
1450/50L G06
LTC1450
Differential Nonlinearity (DNL)
0.2
2
LTC1450
Integral Nonlinearity (INL)
0
– 0.2
0
512 1024 1536 2048 2560 3072 3584 4095
CODE
1450/50L G08
–2
0
512 1024 1536 2048 2560 3072 3584 4095
CODE
1450/50L G09
LTC1450 Total Harmonic
Distortion + Noise vs Frequency
–40
–50
–60
V
CC
= 5V
V
REFHI
= 2V
P-P
V
OUT
= 4V
P-P
LTC1450
Broadband Output Noise
CODE = FFF
H
X1/X2 = GND
BW = 3Hz to 1.2MHz
TOTAL = 0.35mV
RMS
5ms/DIV
1450/50L G12
5
微控制器 MCU
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
