1
LTC7541A
Improved
Industry Standard CMOS
12-Bit Multiplying DAC
s
Improved Direct Replacement for AD7541A
and AD7541
s
4-Quadrant Multiplication
s
12-Bit End-Point Linearity:
0.5LSB DNL and INL
Over Temperature
s
All Grades Guaranteed Monotonic
s
Maximum Gain Error:
1LSB
s
Single 5V to 15V Supply
s
TTL and CMOS Logic Compatible
s
Reduced Sensitivity to Op Amp Offset
s
Low Power Consumption
s
Virtually Latch-Up Proof
s
Low Cost
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.
FEATURES
DESCRIPTIO
N
U
s
Motion Control Systems
s
Microprocessor-Controlled Calibration
s
Automatic Test Equipment
s
Programmable Gain Amplifiers
s
Digitally Controlled Filters
APPLICATIO
N
S
U
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
N
U
2-Quadrant Multiplying DAC Has Less Than
0.5LSB (Typ) Total Unadjusted Error
DIGITAL INPUT CODE
0
INTEGRAL NONLINEARITY (LSB)
4095
7541A TA02
1024
2048
3072
1.0
0.5
0
0.5
1.0
512
1536
2560
3584
T
A
= 85
C
T
A
= 25
C
T
A
= 40
C
Integral Nonlinearity Over Temperature
V
DD
V
REF
LTC7541A
R
FB
GND
3
4 TO 15
2
16
15V
V
IN
17
18
1
OUT 1
33pF
V
OUT
7541 TA01
OUT 2
+
0.1
F
LT
1097
DIGITAL INPUTS
2
LTC7541A
ABSOLUTE
M
AXI
M
U
M
RATINGS
W
W
W
U
PACKAGE/ORDER I
N
FOR
M
ATIO
N
W
U
U
ELECTRICAL CHARACTERISTICS
V
DD
= 15V, V
REF
= 10V, OUT 1 = OUT 2 = GND = 0V, T
A
= T
MIN
to T
MAX
, unless otherwise specified.
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
LTC7541ABN
LTC7541ABSW
LTC7541AJN
LTC7541AKN
LTC7541AJSW
LTC7541AKSW
ORDER PART
NUMBER
Consult factory for Military grade parts.
T
JMAX
= 150
C,
JA
= 100
C/ W (N)
T
JMAX
= 150
C,
JA
= 130
C/ W (SW)
LTC7541AK/LTC7541AB
1
2
3
4
5
6
7
8
9
TOP VIEW
N PACKAGE
18-LEAD PDIP
SW PACKAGE
18-LEAD PLASTIC SO WIDE
18
17
16
15
14
13
12
11
10
OUT 1
OUT 2
GND
BIT 1 (MSB)
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
R
FB
V
REF
V
DD
BIT 12 (LSB)
BIT 11
BIT 10
BIT 9
BIT 8
BIT 7
LTC7541AJ
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX
MIN
TYP
MAX
UNITS
Accuracy
Resolution
q
12
12
Bits
INL
Integral Nonlinearity
(Note 1)
q
1
0.5
LSB
(Relative Accuracy)
DNL
Differential Nonlinearity
Guaranteed Monotonic, T
MIN
to T
MAX
q
1
0.5
LSB
GE
Gain Error
(Note 2)
T
A
= 25
C
6
1
LSB
T
MIN
to T
MAX
q
8
2
LSB
Gain Temperature Coefficient
(Note 3)
q
1
5
1
5
ppm/
C
I
LKG
Output Leakage Current
(Note 4)
T
A
= 25
C
5
5
nA
T
MIN
to T
MAX
q
10
10
nA
PSRR
Power Supply Rejection
V
DD
= 15V
5%
q
0.002
0.002
%/%
Reference Input
R
REF
V
REF
Input Resistance
q
7
11
15
7
11
15
k
V
REF
Input Resistance
100
100
ppm/
C
Temperature Coefficient
3
LTC7541A
V
DD
= 15V, V
REF
= 10V, OUT 1 = OUT 2 = GND = 0V, T
A
= T
MIN
to T
MAX
, unless otherwise specified.
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
.
Note 5: OUT 1 load = 100
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.
ELECTRICAL CHARACTERISTICS
BLOCK DIAGRA
M
W
40k
10k
40k
20k
40k
20k
40k
20k
40k
40k
40k
DECODER
BIT 1
(MSB)
BIT 2
GND
V
DD
V
REF
R
FB
BIT 3
BIT 4
BIT 12
(LSB)
OUT 1
OUT 2
7541 BD
TTL/DTL/CMOS COMPATIBLE DIGITAL INPUTS
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.
ALL GRADES
SYMBOL PARAMETER
CONDITIONS
MIN
TYP
MAX
UNIT
Power Supply
V
DD
Operating Supply Range
q
5
15
16
V
I
DD
Suppy Current
Digital Inputs = V
IH
or V
IL
q
2
mA
Digital Inputs = 0V or V
DD
q
100
A
Digital Inputs
V
IH
Digital Input High Voltage
q
2.4
V
V
IL
Digital Input Low Voltage
q
0.8
V
I
IN
Digital Input Current
q
0.001
1
A
C
IN
Digital Input Capacitance
(Note 3), V
IN
= 0V
q
8
pF
AC Performance
Propagation Delay
(Notes 5, 6)
100
ns
Digital-to-Analog Glitch Impulse
(Notes 5, 7)
1000
nV-sec
Multiplying Feedthrough Error
V
REF
=
10V, 10kHz Sinewave
1.0
mV
P-P
Output Current Settling Time
(Note 5), To 0.01% for Full-Scale Change
0.6
s
C
OUT
Output Capacitance (Note 3)
Digital Inputs = V
IH
C
OUT1
q
200
pF
C
OUT2
q
70
pF
Digital Inputs = V
IL
C
OUT1
q
70
pF
C
OUT2
q
200
pF
4
LTC7541A
TYPICAL APPLICATIO
N
S
N
U
Unipolar Operation (2-Quadrant Multiplication)
RELATED PARTS
Bipolar Operation (4-Quadrant Multiplication)
V
DD
V
REF
LTC7541A
R
FB
GND
3
4 TO 15
2
16
15V
V
REF
10 TO 10V
17
18
1
OUT 1
33pF
R1
10k
V
OUT
7541 TA04
OUT 2
+
0.1
F
1/2 LT1112
+
1/2 LT1112
DIGITAL INPUTS
Table 2. Bipolar Offset Binary Code Table
DIGITAL INPUT
V
REF
(2047/2048)
V
REF
(1/2048)
0V
V
REF
(1/2048)
V
REF
MSB
LSB
1111 1111 1111
1000 0000 0001
1000 0000 0000
0111 1111 1111
0000 0000 0000
ANALOG OUTPUT
V
OUT
R2
20k
R3
20k
V
DD
V
REF
LTC7541A
R
FB
GND
3
4 TO 15
2
16
15V
V
REF
10 TO 10V
17
18
1
OUT 1
33pF
V
OUT
7541 TA03
OUT 2
+
0.1
F
LT1097
DIGITAL INPUTS
Table 1. Unipolar Binary Code Table
DIGITAL INPUT
V
REF
(4095/4096)
V
REF
(2048/4096) = V
REF
/ 2
V
REF
(1/4096)
0V
MSB
LSB
1111 1111 1111
1000 0000 0000
0000 0000 0001
0000 0000 0000
ANALOG OUTPUT
V
OUT
PART NUMBER
DESCRIPTION
COMMENTS
LTC1257
Complete Serial I/O V
OUT
12-Bit DAC
5V to 15V Single Supply in 8-Pin SO and PDIP
LTC1451/LTC1452/LTC1453
Complete Serial I/O V
OUT
12-Bit DACs
3V/5V Single Supply in 8-Pin SO and PDIP
LTC7543/LTC8143
Serial I/O Muliplying 12-Bit DACs
Clear Pin, Serial Data Output (LTC8143)
LTC8043
Serial Mulitplying 12-Bit DAC
8-Pin SO and PDIP
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7487
(408) 432-1900
q
FAX
: (408) 434-0507
q
TELEX
: 499-3977
LT/GP 1195 6K PRINTED IN USA
LINEAR TECHNOLOGY CORPORATION 1995
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