LTC7545A
Improved Industry Standard
Parallel 12-Bit Multiplying DAC
FEATURES
s
s
s
s
s
s
s
DESCRIPTIO
Improved Direct Replacement for AD7545A
and AD7545
DNL and INL Over Temperature:
±0.5LSB
Gain Error:
±1LSB
Maximum
4-Quadrant Multiplication
Single 5V or 15V Supply
Low Power Consumption
Low Cost
The LTC
®
7545A is a 12-bit multiplying digital-to-analog
converter (DAC) with a microprocessor compatible paral-
lel input. It is a superior pin compatible replacement for the
industry standard AD7545A and AD7545. Improvements
include better accuracy, better stability over temperature
and supply variations and lower sensitivity to output
amplifier offset.
This very versatile DAC is useful for 2-quadrant and
4-quadrant multiplying, programmable gain and filtering
and single supply noninverting voltage output operation.
Parts are available in 20-pin PDIP and SO packages and
commercial and industrial temperature grades.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATI
s
s
s
s
S
Process Control and Industrial Automation
Software Controlled Gain Adjustment
Digitally Controlled Filter and Power Supplies
Automatic Test Equipment
TYPICAL APPLICATI
2-Quadrant Multiplying DAC Has Less Than
0.5LSB (Typ) Total Unadjusted Error
V
IN
5V
0.1µF
Integral Nonlinearity Over Temperature
1.0
INTEGRAL NONLINEARITY (LSB)
18
19
20
R
FB
1
OUT1
33pF
0.5
T
A
= 85°C
0
T
A
= –40°C
–0.5
T
A
= 25°C
CS
16
AGND
2
DGND
4–15
3
+
WR
17
LTC7545A
–
V
DD
V
REF
LT
®
1097
V
OUT
7545A TA01
–1.0
0
512 1024 1536 2048 2560 3072 3584 4095
DIGITAL INPUT CODE
7545A TA02
U
UO
UO
1
LTC7545A
ABSOLUTE
AXI U
RATI GS
PACKAGE/ORDER I FOR ATIO
TOP VIEW
OUT1 1
AGND 2
DGND 3
DB11 (MSB) 4
DB10 5
DB9 6
DB8 7
DB7 8
DB6 9
DB5 10
G PACKAGE
20-LEAD PLASTIC SSOP
20 R
FB
19 V
REF
18 V
DD
17 WR
16 CS
15 DB0 (LSB)
14 DB1
13 DB2
12 DB3
11 DB4
N PACKAGE
20-LEAD PDIP
V
DD
to AGND ............................................ –0.5V to 17V
V
DD
to DGND ............................................. –0.5V to 17V
AGND to DGND .............................. –0.5V to V
DD
+ 0.5V
DGND to AGND .............................. –0.5V to V
DD
+ 0.5V
V
REF
to AGND,DGND .............................................
±25V
R
FB
to AGND,DGND ............................................. .
±25V
Digital Inputs to DGND ................. – 0.5V to V
DD
+ 0.5V
V
OUT1
to AGND, DGND ................. –0.5V to V
DD
+ 0.5V
Maximum Junction Temperature .......................... 150°C
Operating Temperature Range
Commercial (K, L Versions) .................... 0°C to 70°C
Industrial (B, C Versions)................... –40° C to 85°C
Storage Temperature Range ................ –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
ORDER PART
NUMBER
LTC7545ABG
LTC7545ABN
LTC7545ABSW
LTC7545ACG
LTC7545ACN
LTC7545ACSW
LTC7545AKG
LTC7545AKN
LTC7545AKSW
LTC7545ALG
LTC7545ALN
LTC7545ALSW
SW PACKAGE
20-LEAD PLASTIC SO WIDE
T
JMAX
= XXX°C,
θ
JA
= XXX°C/W (G)
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
= 5V or 15V, V
REF
= 10V, V
OUT1
= AGND = 0V, T
A
= T
MIN
to T
MAX,
unless otherwise noted.
SYMBOL
Accuracy
INL
DNL
GE
PARAMETER
Resolution
Integral Nonlinearity
(Relative Accuracy)
Differential Nonlinearity
Gain Error
Gain Temperature Coefficient
OUT1 Leakage Current
CONDITIONS
q
LTC7545AK/AB
MIN
TYP
MAX
12
±0.5
±0.5
±1
±1
±2
±3
5
±10
±50
±0.002
15
1
150
5
5
30
60
70
150
LTC7545AL/AC
MIN
TYP
MAX
12
±0.5
±0.5
±0.5
±0.5
±1
±2
5
±10
±50
±0.002
15
1
150
5
5
30
60
70
150
UNITS
Bits
LSB
LSB
LSB
LSB
LSB
LSB
ppm/°C
nA
nA
%/%
kΩ
µs
ns
nV-sec
mV
P-P
pF
pF
I
LKG
T
A
= 25°C
T
MIN
to T
MAX
Guaranteed Monotonic T
A
= 25°C
T
MIN
to T
MAX
T
MIN
to T
MAX
(Note 2)
T
A
= 25°C
T
MIN
to T
MAX
(Note 3)
∆Gain/∆Temperature
(Note 4)
T
A
= 25°C
T
MIN
to T
MAX
(Note 1)
q
q
q
q
q
q
1
1
PSRR
Power Supply Rejection
Reference Input
R
REF
V
REF
Input Resistance
AC Performance
Output Current Settling Time
Propagation Delay
Digital-to-Analog Glitch Impulse
Multiplying Feedthrough Error
Analog Outputs
C
OUT
Output Capacitance (Note 3)
(Note 5)
(Notes 3, 6, 7)
(Notes 3, 6, 8)
(Notes 6, 9)
V
REF
=
±10V,
10kHz Sine Wave
DB0 to DB11 = 0V,
WR, CS = 0V
DB0 to DB11 = V
DD,
WR, CS = 0V
C
OUT1
C
OUT1
q
q
q
q
q
q
q
8
11
8
11
2
U
W
U
U
W W
W
LTC7545A
ELECTRICAL CHARACTERISTICS
V
DD
= 5V, V
REF
= 10V, V
OUT1
= AGND = 0V, T
A
= T
MIN
to T
MAX,
unless otherwise noted.
SYMBOL
Digital Inputs
V
IH
V
IL
I
IN
C
IN
t
CS
t
CH
t
WR
t
DS
t
DH
Power Supply
V
DD
I
DD
Supply Voltage
Supply Current
All Digital Inputs = V
IH
or V
IL
All Digital Inputs = 0V or V
DD
q
q
q
PARAMETER
Digital Input High Voltage
Digital Input Low Voltage
Digital Input Current
Digital Input Capacitance
CS to WR Setup Time
CS to WR Hold Time
Write Pulse Width
Data Setup Time
Data Hold Time
CONDITIONS
q
q
q
MIN
2.4
ALL GRADES
TYP
MAX
UNITS
V
0.8
0.001
±1
8
100
0
100
100
5
4.75
5
10
5.25
2
100
V
µA
pF
ns
ns
ns
ns
ns
V
mA
µA
(Note 3) V
IN
= 0V
q
Timing Characteristics (Note 3)
q
q
q
q
q
V
DD
= 15V, V
REF
= 10V, V
OUT1
= AGND = 0V, T
A
= T
MIN
to T
MAX,
unless otherwise noted.
SYMBOL
Digital Inputs
V
IH
V
IL
I
IN
C
IN
t
CS
t
CH
t
WR
t
DS
t
DH
Power Supply
V
DD
I
DD
Supply Voltage
Supply Current
All Digital Inputs = V
IH
or V
IL
All Digital Inputs = 0V or V
DD
q
q
q
PARAMETER
Digital Input High Voltage
Digital Input Low Voltage
Digital Input Current
Digital Input Capacitance
CS to WR Setup Time
CS to WR Hold Time
Write Pulse Width
Data Setup Time
Data Hold Time
CONDITIONS
q
q
q
MIN
13.5
ALL GRADES
TYP
MAX
UNITS
V
1.5
±1
8
75
0
75
60
5
14.25
15
10
15.75
2
100
V
µA
pF
ns
ns
ns
ns
ns
V
mA
µA
(Note 3) V
IN
= 0V
q
Timing Characteristics (Note 3)
q
q
q
q
q
The
q
denotes specificatons 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 DAC register loaded to all 0s.
Note 5:
Typical temperature coefficient is 100ppm/°C.
Note 6:
OUT1 load = 100Ω in parallel with 13pF.
Note 7:
To 0.01% for a full-scale change, measured from the falling
edge of WR, CS = 0V.
Note 8:
From digital input change to 90% of final analog output.
Note 9:
V
REF
= 0V. DAC register contents changed from all 0s to all 1s
or all 1s to all 0s.
3
LTC7545A
BLOCK DIAGRAM
W
20k
V
REF
19
40k
40k
40k
40k
40k
40k
40k
10k
20k
20k
20 R
FB
1 OUT1
2 AGND
V
DD
18
DECODER
3 DGND
WR 17
CS 16
LOAD
INPUT DATA LATCHES
4
DB11
(MSB)
5
DB10
6
DB9
7
DB8
• • • • • • • 15
DB0
(LSB)
7545A BD
TI I G DIAGRA
4
W
t
CS
CS
t
CH
t
WR
WR
t
DS
DATA IN
DB0 to DB11
DATA VALID
7545A TD
UW
t
DH
LTC7545A
TYPICAL APPLICATIONS
N
Unipolar Operation (2-Quadrant Multiplication)
V
REF
–10V TO 10V
5V OR 15V
0.1µF
19
18
20
V
DD
V
REF
R
FB
17
16
µP
4–15
WR
CS
LTC7545A
OUT1
AGND
DGND
3
1
2
33pF
Table 1. Unipolar Binary Code Table
DIGITAL INPUT
BINARY NUMBER
ANALOG OUTPUT
IN DAC LATCH
V
OUT
MSB
LSB
1111
1111
1111
– V
REF
(4095/4096)
1000
0000
0000
– V
REF
(2048/4096) = – V /2
REF
0000
0000
0001
– V
REF
(1/4096)
0000
0000
0000
0V
+
DB11 to DB0
–
U
LT1097
V
OUT
0V TO – V
REF
7545A TA03
5
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