LTC7541A
Improved
Industry Standard CMOS
12-Bit Multiplying DAC
FEATURES
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DESCRIPTION
The LTC
®
7541A is a 12-bit resolution multiplying digital-
to-analog converter (DAC).
Laser-trimmed thin-film resistors provide excellent abso-
lute accuracy. Precision matched resistors and CMOS
circuitry result in remarkable stability with temperature
and supply variations.
The LTC7541A is a superior pin compatible replacement
for the industry standard AD7541A/AD7541. Improve-
ments include better typical accuracy and stability and
reduced sensitivity to output amplifier offset. The LTC7541A
is also very resistant to latch-up.
In addition to 2-quadrant and 4-quadrant multiplying
configurations, the LTC7541A performs well in digitally
programmable gain and noninverting voltage output ap-
plications. Low cost, improved performance and versatil-
ity make the LTC7541A the best choice for many new
designs and for upgrading existing systems. Parts are
available in 18-pin PDIP and 18-pin SO Wide packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
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Improved Direct Replacement for AD7541A
and AD7541
4-Quadrant Multiplication
12-Bit End-Point Linearity:
±
0.5LSB DNL and INL
Over Temperature
All Grades Guaranteed Monotonic
Maximum Gain Error:
±
1LSB
Single 5V to 15V Supply
TTL and CMOS Logic Compatible
Reduced Sensitivity to Op Amp Offset
Low Power Consumption
Virtually Latch-Up Proof
Low Cost
APPLICATIONS
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Motion Control Systems
Microprocessor-Controlled Calibration
Automatic Test Equipment
Programmable Gain Amplifiers
Digitally Controlled Filters
TYPICAL APPLICATION
2-Quadrant Multiplying DAC Has Less Than
0.5LSB (Typ) Total Unadjusted Error
V
IN
15V
Integral Nonlinearity Over Temperature
1.0
INTEGRAL NONLINEARITY (LSB)
0.1µF
16
V
DD
17
V
REF
18
R
FB
1
OUT 1
33pF
0.5
T
A
= 85°C
0
T
A
= –40°C
–0.5
T
A
= 25°C
LTC7541A
OUT 2
2
GND
4 TO 15
DIGITAL INPUTS
3
LT
®
1097
V
OUT
7541 TA01
–1.0
0
512 1024 1536 2048 2560 3072 3584 4095
DIGITAL INPUT CODE
7541A TA02
U
+
–
U
U
1
LTC7541A
ABSOLUTE
MAXIMUM
RATINGS
V
DD
to GND ............................................... – 0.5V to 17V
V
REF
to GND..........................................................
±25V
R
FB
to GND ...........................................................
±25V
Digital Inputs to GND .................. – 0.5V to (V
DD
+ 0.5V)
OUT 1, OUT 2 to GND .................. – 0.5V to (V
DD
+ 0.5V)
Power Dissipation ............................................. 450mW
(Derate 6mW/°C Above 75°C)
Maximum Junction Temperature ......... – 65°C to 125°C
Operating Temperature Range
Commercial (J, K Versions).................. 0°C to 70°C
Industrial (B Version) ...................... – 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
OUT 1
OUT 2
GND
BIT 1 (MSB)
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
1
2
3
4
5
6
7
8
9
18 R
FB
17 V
REF
16 V
DD
15 BIT 12 (LSB)
14 BIT 11
13 BIT 10
12 BIT 9
11 BIT 8
10 BIT 7
SW PACKAGE
18-LEAD PLASTIC SO WIDE
ORDER PART
NUMBER
LTC7541ABN
LTC7541ABSW
LTC7541AJN
LTC7541AKN
LTC7541AJSW
LTC7541AKSW
N PACKAGE
18-LEAD PDIP
T
JMAX
= 150°C,
θ
JA
= 100°C/ W (N)
T
JMAX
= 150°C,
θ
JA
= 130°C/ W (SW)
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
V
DD
= 15V, V
REF
= 10V, OUT 1 = OUT 2 = GND = 0V, T
A
= T
MIN
to T
MAX
, unless otherwise specified.
SYMBOL PARAMETER
Accuracy
Resolution
INL
DNL
GE
Integral Nonlinearity
(Relative Accuracy)
Differential Nonlinearity
Gain Error
Gain Temperature Coefficient
I
LKG
PSRR
R
REF
Output Leakage Current
Power Supply Rejection
V
REF
Input Resistance
V
REF
Input Resistance
Temperature Coefficient
(Note 1)
Guaranteed Monotonic, T
MIN
to T
MAX
(Note 2)
(Note 3)
(Note 4)
V
DD
= 15V
±5%
T
A
= 25°C
T
MIN
to T
MAX
T
A
= 25°C
T
MIN
to T
MAX
q
q
q
q
q
q
q
CONDITIONS
LTC7541AJ
MIN TYP
MAX
12
±1
±1
±6
±8
1
5
±5
±10
±0.002
7
11
– 100
15
LTC7541AK/LTC7541AB
MIN
TYP
MAX
12
±0.5
±0.5
±1
±2
1
5
±5
±10
±0.002
7
11
– 100
15
UNITS
Bits
LSB
LSB
LSB
LSB
ppm/°C
nA
nA
%/%
kΩ
ppm/°C
Reference Input
q
2
U
W
U
U
W W
W
LTC7541A
ELECTRICAL CHARACTERISTICS
V
DD
= 15V, V
REF
= 10V, OUT 1 = OUT 2 = GND = 0V, T
A
= T
MIN
to T
MAX
, unless otherwise specified.
SYMBOL PARAMETER
Power Supply
V
DD
I
DD
Operating Supply Range
Suppy Current
Digital Inputs = V
IH
or V
IL
Digital Inputs = 0V or V
DD
q
q
q
CONDITIONS
ALL GRADES
MIN
TYP
MAX
5
15
16
2
100
2.4
0.8
0.001
±1
8
100
1000
1.0
0.6
q
q
q
q
UNIT
V
mA
µA
V
V
µA
pF
ns
nV-sec
mV
P-P
µs
Digital Inputs
V
IH
V
IL
I
IN
C
IN
Digital Input High Voltage
Digital Input Low Voltage
Digital Input Current
Digital Input Capacitance
Propagation Delay
Digital-to-Analog Glitch Impulse
Multiplying Feedthrough Error
Output Current Settling Time
C
OUT
Output Capacitance (Note 3)
(Note 3), V
IN
= 0V
(Notes 5, 6)
(Notes 5, 7)
V
REF
=
±10V,
10kHz Sinewave
(Note 5), To 0.01% for Full-Scale Change
Digital Inputs = V
IH
Digital Inputs = V
IL
The
q
denotes specifications which apply over the full operating
temperature range.
Note 1:
±0.5LSB
=
±0.012%
of full scale.
Note 2:
Using internal feedback resistor.
Note 3:
Guaranteed by design, not subject to test.
Note 4:
I
OUT1
with all digital inputs = 0V or I
OUT2
with all digital
inputs = V
DD
.
C
OUT1
C
OUT2
C
OUT1
C
OUT2
q
q
q
q
AC Performance
200
70
70
200
pF
pF
pF
pF
Note 5:
OUT 1 load = 100Ω in parallel with 13pF.
Note 6:
Measured from digital input change to 90% of final analog value.
Digital inputs = 0V to V
DD
or V
DD
to 0V.
Note 7:
V
REF
= 0V. All digital inputs 0V to V
DD
or V
DD
to 0V. Measured
using LT1363 as output amplifier.
BLOCK DIAGRAM
V
REF
V
DD
DECODER
W
20k
40k
40k
40k
40k
20k
40k
20k
R
FB
40k
40k
10k
OUT 1
OUT 2
TTL/DTL/CMOS COMPATIBLE DIGITAL INPUTS
• • • •
GND
BIT 1
(MSB)
BIT 2
BIT 3
BIT 4
BIT 12
(LSB)
7541 BD
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
3
LTC7541A
TYPICAL APPLICATIONS
N
Unipolar Operation (2-Quadrant Multiplication)
V
REF
– 10 TO 10V
15V
0.1µF
16
V
DD
17
V
REF
18
R
FB
1
OUT 1
LTC7541A
OUT 2
2
GND
4 TO 15
DIGITAL INPUTS
3
Bipolar Operation (4-Quadrant Multiplication)
R2
20k
15V
R3
20k
V
REF
– 10 TO 10V
0.1µF
16
V
DD
17
V
REF
18
R
FB
1
OUT 1
LTC7541A
OUT 2
2
GND
4 TO 15
DIGITAL INPUTS
3
1/2 LT1112
Table 2. Bipolar Offset Binary Code Table
DIGITAL INPUT
MSB
1111
1000
1000
0111
0000
1111
0000
0000
1111
0000
LSB
1111
0001
0000
1111
0000
ANALOG OUTPUT
V
OUT
V
REF
(2047/2048)
V
REF
(1/2048)
0V
–V
REF
(1/2048)
–V
REF
RELATED PARTS
PART NUMBER
LTC1257
LTC1451/LTC1452/LTC1453
LTC7543/LTC8143
LTC8043
DESCRIPTION
Complete Serial I/O V
OUT
12-Bit DAC
Complete Serial I/O V
OUT
12-Bit DACs
Serial I/O Muliplying 12-Bit DACs
Serial Mulitplying 12-Bit DAC
COMMENTS
5V to 15V Single Supply in 8-Pin SO and PDIP
3V/5V Single Supply in 8-Pin SO and PDIP
Clear Pin, Serial Data Output (LTC8143)
8-Pin SO and PDIP
LT/GP 1195 6K • PRINTED IN USA
4
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7487
(408) 432-1900
q
FAX
: (408) 434-0507
q
TELEX
: 499-3977
+
–
+
–
+
–
U
Table 1. Unipolar Binary Code Table
33pF
DIGITAL INPUT
LT1097
V
OUT
ANALOG OUTPUT
V
OUT
–V
REF
(4095/4096)
–V
REF
(2048/4096) = –V
REF
/ 2
–V
REF
(1/4096)
0V
7541 TA03
MSB
1111
1000
0000
0000
1111
0000
0000
0000
LSB
1111
0000
0001
0000
33pF
R1
10k
1/2 LT1112
V
OUT
7541 TA04
©
LINEAR TECHNOLOGY CORPORATION 1995
工业自动化与控制
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