19-0158; Rev 0; 7/93
Complete, Dual, 12-Bit
Multiplying DACs
_______________General Description
The MX7837/MX7847 are dual, 12-bit, multiplying, volt-
age-output digital-to-analog converters (DACs). Each
DAC has an output amplifier and a feedback resistor.
The output amplifier is capable of developing ±10V
across a 2kΩ load. The amplifier feedback resistor is
internally connected to V
OUT
on the MX7847. No exter-
nal trims are required to achieve full 12-bit performance
over the entire operating temperature range.
The MX7847 has a 12-bit parallel data input, whereas
the MX7837 operates with a double-buffered 8-bit-bus
interface that loads data in two write operations. All
logic signals are level triggered and are TTL and CMOS
compatible. Fast timing specifications make these
DACs compatible with most microprocessors.
____________________________Features
o
Two 12-Bit Multiplying DACs with Buffered
Voltage Output
o
Specified with ±12V or ±15V Supplies
o
No External Adjustments Required
o
Fast Timing Specifications
o
24-Pin DIP and SO Packages
o
12-Bit Parallel Interface (MX7847)
8-Bit + 4-Bit Interface (MX7837)
MX7837/MX7847
______________Ordering Information
PART
MX7837JN
MX7837KN
MX7837JR
MX7837KR
MX7837C/D
TEMP. RANGE
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
PIN-PACKAGE
24 Narrow Plastic DIP
24 Narrow Plastic DIP
24 Wide SO
24 Wide SO
Dice*
ERROR
(LSB)
±1
±1/2
±1
±1/2
±1
________________________Applications
Small Component-Count Analog Systems
Digital Offset/Gain Adjustments
Industrial Process Control
Function Generators
Automatic Test Equipment
Automatic Calibration
Machine and Motion Control Systems
Waveform Reconstruction
Synchro Applications
Ordering Information continued on last page.
* Contact factory for availability and processing to MIL-STD-883.
_________Typical Operating Circuits
V
DD
_________________Pin Configurations
TOP VIEW
CS 1
R
FBA
2
V
REFA
3
V
OUTA
4
AGNDA 5
V
DD
6
V
SS
7
AGNDB 8
V
OUTB
9
V
REFB
10
DGND 11
R
FBB
12
24 DB0/DB8
23 DB1/DB9
22 DB2/DB10
21 DB3/DB11
V
REFA
V
REFB
MSB
LSB
INPUT INPUT
LATCH LATCH
4
8
DAC LATCH A
12
DAC A
R
FBA
V
OUTA
AGNDA
DB0
DB7
DAC B
12
DAC LATCH B
8
4
LSB
MSB
INPUT INPUT
LATCH LATCH
R
FBB
V
OUTB
MX7837
20 DB4
19 DB5
18 DB6
17 DB7
16 A0
15 A1
14 LDAC
13 WR
LDAC
CS
WR
A0
A1
AGNDB
CONTROL
LOGIC
MX7837
DIP/SO
DGND
V
SS
MX7847 on last page.
MX7847 on last page.
1
________________________________________________________________
Maxim Integrated Products
Call toll free 1-800-998-8800 for free samples or literature.
Complete, Dual, 12-Bit
Multiplying DACs
MX7837/MX7847
ABSOLUTE MAXIMUM RATINGS
V
DD
to DGND, AGNDA, AGNDB ............................-0.3V to +17V
V
SS
to DGND, AGNDA, AGNDB (Note 1) ..............+0.3V to -17V
V
REFA
, V
REFB
to AGNDA, AGNDB .. (V
SS
- 0.3V) to (V
DD
+ 0.3V)
AGNDA, AGNDB to DGND.........................-0.3V to (V
DD
+ 0.3V)
V
OUTA
, V
OUTB
to AGNDA, AGNDB .....(V
SS
- 0.3V) to (V
DD
+ 0.3V)
R
FBA
, R
FBB
to AGNDA, AGNDB .......(V
SS
- 0.3V) to (V
DD
+ 0.3V)
Digital Inputs to DGND ...............................-0.3V to (V
DD
+ 0.3V)
Continuous Power Dissipation (T
A
= +70°C)
Narrow Plastic DIP (derate 13.33mW/°C above +70°C)....1067mW
SO (derate 11.76mW/°C above +70°C) .........................941mW
Narrow CERDIP (derate 12.50mW/°C above +70°C) ..1000mW
Operating Temperature Ranges:
MX78_7J_/K_ ........................................................0°C to +70°C
MX78_7A_/B_ .................................................. -40°C to +85°C
MX78_7SQ/TQ ............................................... -55°C to +125°C
Storage Temperature Range ............................ -65°C to +150°C
Lead Temperature (soldering, 10sec) .............................+300°C
Note 1:
If V
SS
is open-circuited with V
DD
and either AGND applied, the V
SS
pin will float positive exceeding the
Absolute Maximum Ratings.
If this possibility exists, a Schottky diode connected between V and GND ensures the maximum ratings will be observed.
SS
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
DD
= 11.4V to 16.5V, V
SS
= -11.4V to -16.5V, AGNDA = AGNDB = DGND = 0V, V
REFA
= V
REFB
= +10V, R
L
= 2kΩ, C
L
= 100pF,
V
OUT
connected to R
FB
(MX7837), T
A
= T
MIN
to T
MAX
, unless otherwise noted.) (Note 2)
PARAMETER
SYMBOL
STATIC PERFORMANCE
(Note 3)
Resolution
Relative Accuracy
Differential Nonlinearity
N
INL
DNL
MX78_7J/A/S
MX78_7K/B/T
Guaranteed monotonic
T
A
= +25°C
Zero-Code Offset Error
Loaded with all 0s,
MX78_7J/A
tempco =
±5µV/°C typ T
A
= T
MIN
to T
MAX
MX78_7K/B
MX78_7S/T
Loaded with all 1s,
tempco = ±2ppm
of FSR/°C typ
T
A
= +25°C
T
A
= T
MIN
to T
MAX
MX78_7J/A/S
MX78_7K/B/T
MX78_7J/A/S
MX78_7K/B/T
8
10
±0.5
CONDITIONS
MIN
12
±1
±1/2
±1
±2
±4
±3
±5
±5
±2
±7
±4
13
±3
kΩ
%
LSB
mV
TYP
MAX
UNITS
Bits
LSB
LSB
Gain Error
REFERENCE INPUTS
V
REF
Input Resistance
V
REFA
, V
REFB
Resistance
Matching
DIGITAL INPUTS
Input High Voltage
Input Low Voltage
Input Current
Input Capacitance (Note 4)
ANALOG OUTPUTS
DC Output Impedance
Short-Circuit Current
2
V
OUT
connected to AGND
0.2
15
Ω
mA
V
INH
V
INL
Digital inputs at 0V and V
DD
2.4
0.8
±1
8
V
µA
pF
_______________________________________________________________________________________
Complete, Dual, 12-Bit
Multiplying DACs
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= 11.4V to 16.5V, V
SS
= -11.4V to -16.5V, AGNDA = AGNDB = DGND = 0V, V
REFA
= V
REFB
= +10V, R
L
= 2kΩ, C
L
= 100pF,
V
OUT
connected to R
FB
(MX7837), T
A
= T
MIN
to T
MAX
, unless otherwise noted.) (Note 1)
PARAMETER
POWER REQUIREMENTS
V
DD
Range
V
SS
Range
Positive Supply Current
Negative Supply Current
V
DD
V
SS
I
DD
I
SS
Output unloaded
Output unloaded
11.4
-11.4
5
4
16.5
-16.5
10
6
±0.01
±0.01
±0.01
±0.01
% per %
V
V
mA
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MX7837/MX7847
∆Gain/∆V
DD
V
DD
= 15V ±5%, V
REF
= -10V
Power-Supply Rejection
∆Gain/∆V
SS
V
SS
= -15V ±5%, V
REF
= 10V
∆Gain/∆V
DD
V
DD
= 12V ±5%, V
REF
= -8.9V
∆Gain/∆V
SS
V
SS
= -12V ±5%, V
REF
= 8.9V
AC CHARACTERISTICS
Voltage-Output Settling
Time
Slew Rate
Digital-to Analog Glitch
Impulse
Channel-to-Channel Isolation
(V
REFA
to V
OUTB
,
V
REFB
to V
OUTA
)
Multiplying Feedthrough
Error
Unity-Gain Small-Signal
Bandwidth
Full-Power Bandwidth
Total Harmonic Distortion
Digital Crosstalk
Output Noise Voltage at
+25°C (0.1Hz to 10Hz)
THD
t
S
Settling time to within ±1/2LSB of final DAC value;
DAC latch alternately loaded will all 0s and all 1s
DAC latch alternately loaded with 01…11 and
10…00
V
REF
= 20p-p, 10kHz sine wave, Alternate DAC
Latch Loaded with all 0s
V
REF_
= 20V
p-p
, 10kHz sine wave, latches loaded
with all 0s
V
REF
= 100mV
p-p
sine wave, DAC latch loaded
with all 1s
V
REF
= 20V
p-p
S
ine wave, DAC latch loaded with
all 1s
V
REF
= 6V
RMS
, 1kHz, DAC latch loaded with all 1s
Code transition from all 0s to all 1s; see
Typical
Operating Characteristics
graphs
Amplifier noise and Johnson noise of R
FB
4
7
Q
60
-95
-90
1
125
-88
10
2
µs
V/µs
nV-s
dB
dB
MHz
kHz
dB
nV-s
µV
RMS
Note 2:
The analog outputs can swing to within 2.5V of the supply rails. Hence, for good linearity towards full-scale, |V
REFA
| and |V
REFB
| must
be at least 2.5V lower than V
DD
and |V
SS
|. Tests done with supply voltages below ±12.5V are done with V
REFA
= V
REFB
= ±8.9V.
Note 3:
Static performance tested at V
DD
= +15V, V
SS
= -15V. Performance over supplies guaranteed by PSRR test.
Note 4:
Guaranteed by design.
_______________________________________________________________________________________
3
Complete, Dual, 12-Bit
Multiplying DACs
MX7837/MX7847
TIMING CHARACTERISTICS
(V
DD
= 11.4V to 16.5V, V
SS
= -11.4V to -16.5V, AGNDA = AGNDB = DGND = 0V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.) (Note 5)
PARAMETER
CS
to
WR
Setup Time
CS
to
WR
Hold Time
WR
Pulse Width
Data to
WR
Setup Time
Data to
WR
Hold Time
Address to
WR
SetupTime
Address to
WR
Hold Time
LDAC
Pulse Width
SYMBOL
t
1
t
2
t
3
t
4
t
5
t
6
t
7
t
8
MX7837 only
MX7837 only
MX7837 only
CONDITIONS
MX78_7J/K/A/B
MIN
MAX
0
0
80
80
10
15
15
80
MX78_7S/T
MIN
MAX
0
0
80
80
10
15
15
80
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
Note 5:
All input signals are specified with t
R
= t
F
≤
5ns. Logic swing is 0V to 5V.
__________________________________________Typical Operating Characteristics
(T
A
= +25°C, V
DD
= 15V, V
SS
= -15V, R
L
= 2kΩ, C
L
= 100pF, unless otherwise noted)
OUTPUT VOLTAGE SWING
vs. RESISTIVE LOAD
25
NOISE SPECTRAL DENSITY (nV/ Hz)
V
REF
= 20V
p-p
at 1kHz
20
V
OUT
(V
p-p
)
300
V
REF
= 0V
DAC CODE = 11...111
GAIN = -1
GAIN (dB)
NOISE SPECTRAL DENSITY
5
0
-5
200
-10
-15
-20
0
-25
10
100
1k
FREQUENCY (Hz)
10k
100k
SMALL-SIGNAL FREQUENCY RESPONSE
15
V
REF
= 100mV
p-p
DAC CODE = 11...111
GAIN = -1
10
100
5
0
10
100
1k
10k
LOAD RESISTANCE (Ω)
100
1k
10k
100k
1M
10M
FREQUENCY (Hz)
MULTIPLYING FEEDTHROUGH ERROR
-35
-40
-45
ATTENUATION (dB)
-50
-55
-60
-65
-70
-75
-80
-85
1k
10k
100k
1M
FREQUENCY (Hz)
-106
THD (dB)
V
REFA
= 20V
p-p
V
REFB
= AGNDB
DAC CODE = 00...00
-94
-96
-98
TOTAL HARMONIC DISTORTION + NOISE
vs. FREQUENCY (BANDWIDTH = 80kHz)
-60
V
REF
= 6V
RMS
DAC CODE = 111...111
-65
-70
THD (dB)
-75
-80
-85
-90
-104
-95
-100
100
1k
FREQUENCY (Hz)
10k
TOTAL HARMONIC DISTORTION + NOISE
vs. FREQUENCY (BANDWIDTH > 500kHz)
V
REF
= 6V
RMS
DAC CODE = 111...111
-100
-102
100
1k
10k
100k
FREQUENCY (Hz)
4
_______________________________________________________________________________________
Complete, Dual, 12-Bit
Multiplying DACs
____________________________Typical Operating Characteristics (continued)
(T
A
= +25°C, V
DD
= 15V, V
SS
= -15V, R
L
= 2kΩ, C
L
= 100pF, unless otherwise noted.)
SMALL-SIGNAL PULSE RESPONSE
LARGE-SIGNAL PULSE RESPONSE
MX7837/MX7847
AGNDA
A
AGNDA
A
A = V
OUTA
, 50mV/div
TIMEBASE = 2µs/div
V
REFA
= ±100mV SQUARE WAVE
A = V
OUTA
, 5V/div
TIMEBASE = 2µs/div
V
REFA
= ±10V SQUARE WAVE
______________________________________________________________Pin Description
PIN
MX7837
1
–
2
–
3
4
5
6
7
8
9
10
11
12
–
13
14
–
15
16
17-20
21-24
MX7847
–
1
–
2
3
4
5
6
7
8
9
10
11
–
12
13
–
14-24
–
–
–
–
NAME
CS
CSA
R
FBA
CSB
V
REFA
V
OUTA
AGNDA
V
DD
V
SS
AGNDB
V
OUTB
V
REFB
DGND
R
FBB
DB11
WR
LDAC
DB10-DB0
A1
A0
DB7-DB4
DB3/DB11-
DB0/DB8
Chip Select – active-low logic input
Chip-Select Input for DAC A – active-low logic input
Amplifier Feedback Resistor for DAC A
Chip-Select Input for DAC B – active-low logic input
Reference Input Voltage for DAC A
Analog Output Voltage from DAC A
Analog Ground for DAC A
Positive Power Supply
Negative Power Supply
Analog Ground for DAC B
Analog Output Voltage from DAC B
Reference Input Voltage for DAC B
Digital Ground
Amplifier Feedback Resistor for DAC B
Data Bit 11 (MSB)
Write Input – active-low logic input (MX7837); positive-edge-triggered input used with
CSA
and
CSB
(MX7847)
Asynchronous Load – DAC input, active-low
Data Bit 10 to Data Bit 0 (LSB)
Address Input – most significant address input for input latches
Address Input – least significant address input for input latches
Data Bit 7 to Data Bit 4
Data Bit 3 to Data Bit 0 (LSB), or Data Bit 11 (MSB) to Data Bit 8
FUNCTION
_______________________________________________________________________________________
5
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