TI DAC7801KP Dual monolithic cmos 12-bit multiplying digital-to-analog converter Datasheet

DAC7800
DAC7801
DAC7802
SBAS005A – DECEMBER 2001
Dual Monolithic CMOS 12-Bit Multiplying
DIGITAL-TO-ANALOG CONVERTERS
FEATURES
APPLICATIONS
● TWO DACs IN A 0.3" WIDE PACKAGE
● SINGLE +5V SUPPLY
● HIGH SPEED DIGITAL INTERFACE:
Serial—DAC7800
8 + 4-Bit Parallel—DAC7801
12-Bit Parallel—DAC7802
● MONOTONIC OVER TEMPERATURE
● LOW CROSSTALK: –94dB min
● FULLY SPECIFIED OVER –40OC TO +85OC
●
●
●
●
●
PROCESS CONTROL OUTPUTS
ATE PIN ELECTRONICS LEVEL SETTING
PROGRAMMABLE FILTERS
PROGRAMMABLE GAIN CIRCUITS
AUTO-CALIBRATION CIRCUITS
DESCRIPTION
DAC7802 has a single-buffered 12-bit data word interface.
Parallel data is loaded (edge triggered) into the single DAC
register for each DAC. DAC7802 is packaged in a 24-pin 0.3"
wide plastic DIP.
12
VREF A
RFB A
CSB
WR
12
12-Bit MDAC
DAC A
VREF B
AGND A
RFB B
IOUT B
A1
UPD
A0
WR
CS
CLR
DAC7801
8-Bit Interface
8 Bits + 4 Bits
8
12
12-Bit MDAC
DAC B
AGND B
CS
CLR
UPD B
DAC7800
Serial Interface
CLK
Serial
CSA
IOUT A
DAC7800 features a serial interface capable of clocking-in
data at a rate of at least 10MHz. Serial data is clocked (edge
triggered) MSB first into a 24-bit shift register and then
latched into each DAC separately or simultaneously as
required by the application. An asynchronous CLEAR control
is provided for power-on reset or system calibration functions. It is packaged in a 16-pin 0.3" wide plastic DIP.
DAC7801 has a 2-byte (8 + 4) double-buffered interface.
Data is first loaded (level transferred) into the input registers
in two steps for each DAC. Then both DACs are updated
simultaneously. DAC7801 features an asynchronous CLEAR
control. DAC7801 is packaged in a 24-pin 0.3" wide plastic
DIP.
DAC7802
12-Bit Interface
UPD A
The DAC7800, DAC7801 and DAC7802 are members of a
new family of monolithic dual 12-bit CMOS multiplying Digital-to-Analog Converters (DACs). The digital interface speed
and the AC multiplying performance are achieved by using
an advanced CMOS process optimized for data conversion
circuits. High stability on-chip resistors provide true 12-bit
integral and differential linearity over the wide industrial
temperature range of –40°C to +85°C.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Copyright © 1990, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
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ELECTROSTATIC
DISCHARGE SENSITIVITY
ABSOLUTE MAXIMUM RATINGS
At TA = +25°C, unless otherwise noted.
VDD to AGND .................................................................................. 0V, +7V
VDD to DGND .................................................................................. 0V, +7V
AGND to DGND .......................................................................... –0.3, VDD
Digital Input to DGND ........................................................ –0.3, VDD + 0.3
VREF A, VREF B to AGND ..................................................................... ±16V
VREF A, VREF B to DGND ..................................................................... ±16V
IOUT A, IOUT B to AGND ................................................................. –0.3, VDD
Storage Temperature Range ........................................... –55°C to +125°C
Operating Temperature Range ......................................... –40°C to +85°C
Lead Temperature (soldering, 10s) ................................................. +300°C
Junction Temperature ...................................................................... +175°C
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling
and installation procedures can cause damage.
ESD damage can range from subtle performance degradation
to complete device failure. Precision integrated circuits may be
more susceptible to damage because very small parametric
changes could cause the device not to meet its published
specifications.
PACKAGE/ORDERING INFORMATION
RELATIVE
ACCURACY
GAIN
ERROR
PACKAGE-LEAD
PACKAGE
DESIGNATOR(1)
DAC7800KP
DAC7800LP
DAC7800KU
DAC7800LU
±1LSB
±1/2 LSB
—
—
±3LSB
±1LSB
—
—
DIP-16
DIP-16
SO-16
SO-16
N
N
DW
DW
DAC7801KP
DAC7801LP
DAC7801KU
DAC7801LU
±1LSB
±1/2 LSB
—
—
±3LSB
±1LSB
—
—
DIP-24
DIP-24
SO-24
SO-24
NT
NT
DW
DW
DAC7802KP
DAC7802LP
DAC7802KU
DAC7802LU
±1LSB
±1/2 LSB
—
—
±3LSB
±1LSB
—
—
DIP-24
DIP-24
SO-24
SO-24
NTG
NTG
DW
DW
PRODUCT
SPECIFIED
TEMPERATURE
RANGE
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
PACKAGE
MARKING
ORDERING
NUMBER
TRANSPORT
MEDIA, QUANTITY
DAC7800KP
DAC7800KP
DAC7800LP
DAC7800LP
DAC7800KU DAC7800KU/1K Tape
DAC7800LU DAC7800LU/1K Tape
Rails, 25
Rails, 25
and Reel, 1000
and Reel, 1000
DAC7801KP
DAC7801KP
DAC7801LP
DAC7801LP
DAC7801KU DAC7801KU/1K Tape
DAC7801LU DAC7801LU/1K Tape
Rails, 15
Rails, 15
and Reel, 1000
and Reel, 1000
DAC7802KP
DAC7802KP
DAC7802LP
DAC7802LP
DAC7802KU DAC7802KU/1K Tape
DAC7802LU DAC7802LU/1K Tape
Rails, 15
Rails, 15
and Reel, 1000
and Reel, 1000
NOTE: (1 ) For the most current specifications and package information, refer to our web site at www.ti.com.
ELECTRICAL CHARACTERISTICS
At VDD = +5VDC, VREF A = VREF B = +10V, TA = –40°C to +85°C, unless otherwise noted.
DAC7800, 7801, 7802K
PARAMETER
ACCURACY
Resolution
Relative Accuracy
Differential Nonlinearity
Gain Error
Gain Temperature Coefficient(1)
Output Leakage Current
CONDITIONS
MAX
MIN
TYP
MAX
UNITS
±1/2
✻
±1
Bits
LSB
LSB
LSB
✻
✻
✻
✻
✻
✻
ppm/°C
nA
nA
✻
✻
✻
2
kΩ
%
✻
✻
✻
✻
✻
V
V
µA
µA
pF
✻
✻
✻
V
mA
%/%
✻
±1
±1
±3
Measured Using RFB A and RFB B.
All Registers Loaded with All 1s.
TA = +25°C
TA = –40°C to +85°C
6
2
0.005
3
5
10
150
10
0.5
14
3
0.8
0.8
±1
±10
10
TA = +25°C
TA = –40°C to +85°C
4.5
0.2
VDD from 4.5V to 5.5V
✻
✻
2
CIN (Input Capacitance)
POWER SUPPLY
VDD
IDD
Power-Supply Rejection
TYP
12
REFERENCE INPUT
Input Resistance
Input Resistance Match
DIGITAL INPUTS
VIH (Input HIGH Voltage)
VIL (Input LOW Voltage)
IIN
(Input Current)
MIN
DAC7800, 7801, 7802L
5.5
2
0.002
✻
✻
✻ Same specification as for DAC7800, 7801, 7802K.
2
DAC7800, 7801, 7802
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SBAS005A
AC PERFORMANCE
OUTPUT OP AMP IS OPA602.
At VDD = +5VDC, VREF A = VREF B = +10V, TA = +25°C, unless otherwise noted. These specifications are fully characterized but not subject to test.
DAC7800, 7801, 7802K
PARAMETER
CONDITIONS
TYP
MAX
OUTPUT CURRENT SETTLING TIME
To 0.01% of Full-Scale
RL = 100Ω, CL = 13pF
0.4
0.8
DIGITAL-TO-ANALOG GLITCH IMPULSE
VREF A = VREF B = 0V
RL = 100Ω, CL = 13pF
0.9
fVREF = 10kHz
–75
–72
✻
✻
dB
DAC Loaded with All 0s
DAC Loaded with All 1s
30
70
50
100
✻
✻
✻
✻
pF
pF
AC FEEDTHROUGH
OUTPUT CAPACITANCE
CHANNEL-TO-CHANNEL ISOLATION
VREF A to IOUT B
MIN
DAC7800, 7801, 7802L
fVREF A = 10kHz
VREF B = 0V,
Both DACs Loaded with 1s
fVREF B = 10kHz
VREF A = 0V,
Both DACs Loaded with 1s
VREF B to IOUT A
DIGITAL CROSSTALK
MIN
TYP
MAX
UNITS
✻
✻
µs
✻
nV-s
–90
–94
✻
✻
dB
–90
–101
✻
✻
dB
✻
nV-s
Full-Scale Transition
RL = 100Ω, CL = 13pF
0.9
✻ Same specification as for DAC7800, 7801, and 7802K.
NOTE: (1) Ensured but not tested.
DAC7800
BLOCK DIAGRAM
PIN CONFIGURATION
VDD
Top View
DIP
12
10
UPD B
DAC B Register
15
I OUT B
12
16
AGND B
14
RFB B
Bit 11
13
V REF B
Bit 12
4
VREF A
3
R FB A
2
I OUT A
DAC A Register
1
AGND A
12
6
UPD A
12
Control Logic and Shift Register
DAC7800
5
DAC B
Bit 0
Bit 23
DAC A
12
8
CLK CS
7
Data
In
11
9
CLR
DGND
AGND A
1
16
AGND B
I OUT A
2
15
IOUT B
R FB A
3
14
R FB B
VREF A
4
13
VREF B
CLK
5
12
VDD
UPD A
6
11
CLR
Data In
7
10
UPD B
CS
8
9
DGND
DAC7800
LOGIC TRUTH TABLE
CLK
UPD A
UPD B
CS
CLR
X
X
X
X
X
0
1
0
X
X
X
1
0
0
X
1
0
0
0
0
0
X
1
1
1
1
X
X
X
X = Don’t care.
FUNCTION
All register contents set to 0’s (asynchronous).
No data transfer.
Input data is clocked into input register (location Bit 23) and previous data shifts.
Input register bits 23 (LSB) - 12 (MSB) are loaded into DAC A.
Input register bits 11 (LSB) - 0 (MSB) are loaded into DAC B.
Input register bits 23 (LSB) - 12 (MSB) are loaded into DAC A, and input register bits 11 (LSB) - 0 (MSB)
are loaded into DAC B.
means falling edge triggered.
DAC7800, 7801, 7802
SBAS005A
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3
DAC7800
(Cont.)
DATA INPUT FORMAT
DAC7800 Digital Interface Block Diagram
UPD B
UPD A
DAC A Register
DAC B Register
LSB
MSB
Bit
23
Bit
12
LSB
MSB
Bit
11
Bit
0
CLK
Data In
24-Bit
Shift Register
DAC7800 Data Input Sequence
CLK
Data In
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
Bit 8
Bit 9
Bit 10 Bit 11 Bit 12 Bit 13 Bit 14 Bit 15 Bit 16 Bit 17 Bit 18 Bit 19 Bit 20
MSB
DAC B
Bit 21 Bit 22 Bit 23
LSB MSB
DAC B DAC A
LSB
DAC A
TIMING CHARACTERISTICS
VDD = +5V, VREF A = VREF B = +10V, TA = –40°C to +85°C.
t5
PARAMETER
t1 — Data Setup Time
t2 — Data Hold Time
t3 — Chip Select to CLK,
Update, Data Setup Time
t4 — Chip Select to CLK,
Update, Data Hold Time
t5 — CLK Pulse Width
t6 — Clear Pulse Width
t7 — Update Pulse Width
t8 — CLK Edge to UPD A
or UPD B
4
MINIMUM
CLK
0V
t1
15ns
15ns
15ns
DATA
40ns
CS
40ns
40ns
40ns
15ns
UPD A
UPD B
5V
0V
t3
t2
5V
t8
t7
t4
5V
t6
5V
CLR
NOTES: (1) All input signal rise and fall times are measured from 10% to 90% of +5V. t R = t F = 5ns.
(2) Timing measurement reference level is VIH + V IL .
2
DAC7800, 7801, 7802
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SBAS005A
DAC7801
BLOCK DIAGRAM
PIN CONFIGURATION
VDD
Top View
DIP
20
DAC7801
DAC A
LS
Input
Reg
DAC A
MS
Input
Reg
AGND A
1
24
AGND B
IOUT A
2
23
I OUT B
RFB A
3
22
RFB B
VREF A
4
21
V REF B
20
V DD
19
UPD
4
8
DAC A Register
2
I OUT A
1
AGND A
3
R FB A
CS
5
4
V REF A
DB0
6
21
V REF B
DB1
7
18
WR
22
R FB B
DB2
8
17
CLR
23
I OUT B
DB3
9
16
A1
24
AGND B
DB4
10
15
A0
DB5
11
14
DB7
DGND
12
13
DB6
12
19
A1
16
A0
15
CS
5
WR
18
CLR
17
DAC A
Control Logic
UPD
DAC B
12
DAC B Register
14
4
8
DAC B
MS
Input
Reg
DAC B
LS
Input
Reg
DAC7801
12
6
DGND
DB7–DB0
LOGIC TRUTH TABLE
CLR
UPD
CS
WR
A1
A0
1
1
0
1
1
1
1
1
1
1
1
X
1
1
1
1
0
0
1
X
X
0
0
0
0
1
0
X
1
X
0
0
0
0
0
0
X
X
X
0
0
1
1
X
X
X
X
X
0
1
0
1
X
X
FUNCTION
No Data Transfer
No Data Transfer
All Registers Cleared
DAC A LS Input Register Loaded with DB7 - DB0 (LSB)
DAC A MS Input Register Loaded with DB3 (MSB) - DB0
DAC B LS Input Register Loaded with DB7 - DB0 (LSB)
DAC B MS Input Register Loaded with DB3 (MSB) - DB0
DAC A, DAC B Registers Updated Simultaneously from Input Registers
DAC A, DAC B Registers are Transparent
X = Don’t care.
TIMING CHARACTERISTICS
VDD = +5V, VREF A = VREF B = +10V, TA = –40°C to +85°C.
t1
t2
5V
0V
A0–A1
t3
PARAMETER
t1 — Address Valid to Write Setup Time
t2 — Address Valid to Write Hold Time
t3 — Data Setup Time
t4 — Data Hold Time
t5 — Chip Select or Update to Write Setup Time
t6 — Chip Select or Update to Write Hold Time
t7 — Write Pulse Width
t8 — Clear Pulse Width
MINIMUM
10ns
10ns
30ns
10ns
0ns
0ns
40ns
40ns
t4
5V
0V
DATA
t5
t6
5V
0V
CS, UPD
t7
WR
t8
CLR
5V
0V
5V
0V
NOTES: (1) All input signal rise and fall times are measured from 10% to 90%
of +5V. t = t = 5ns. (2) Timing measurement reference level is VIH + VIL .
R
F
2
DAC7800, 7801, 7802
SBAS005A
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5
DAC7802
BLOCK DIAGRAM
PIN CONFIGURATION
Top View
DIP
VDD
21
12
DAC7802
DAC A Register
CK
12
DAC A
5
CS A
CS B
DAC B
20
12
WR
19
CK
2
IOUT A
3
R FB A
4
V REF A
22
V REF B
23
R FB B
24
I OUT B
1
AGND
DGND
18
1
24
I OUT B
IOUT A
2
23
R FB B
R FB A
3
22
V REF B
V REF A
4
21
V DD
CS A
5
20
CS B
(LSB) DB0
6
19
WR
DB1
7
18
DB11 (MSB)
DB2
8
17
DB10
DB3
9
16
DB9
DB4
10
15
DB8
DB5
11
14
DB7
DGND
12
13
DB6
DAC7802
DAC B Register
12
12
AGND
6
DB11–DB0
TIMING CHARACTERISTICS
At VDD = +5V, and TA = –40oC to +85oC.
t1
t2
5V
0V
DATA
PARAMETER
t1
t2
t3
t4
t5
-
t3
MINIMUM
Data Setup Time
Data Hold Time
Chip Select to Write Setup Time
Chip Select to Write Hold Time
Write Pulse Width
t4
CSA, CSB
20ns
15ns
30ns
0ns
30ns
t5
5V
5V
WR
NOTES: (1) All input signal rise and fall times are measured from 10%
to 90% of +5V. tR = tR = 5ns. (2) Timing measurement reference level
VIH + VIL
is
.
2
LOGIC TRUTH TABLE
CSA
CSB
WR
X
X
1
No Data Transfer
1
1
X
No Data Transfer
0
A Rising Edge on CSA or CSB Loads
Data to the Respective DAC
0
1
DAC A Register Loaded from Data Bus
1
0
DAC B Register Loaded from Data Bus
0
0
DAC A and DAC B Registers Loaded
from Data Bus
X = Don’t care.
6
FUNCTION
means rising edge triggered.
DAC7800, 7801, 7802
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SBAS005A
TYPICAL CHARACTERISTICS
OUTPUT OP AMP IS OPA602.
TA = +25°C, VDD = +5V.
OUTPUT LEAKAGE CURRENT
vs TEMPERATURE
THD + NOISE vs FREQUENCY
–60
–65
100n
–70
THD + Noise (dB)
Output Leakage Current (A)
1µ
10n
1n
100p
–75
1Vrms
–80
3Vrms
–85
6Vrms
–90
10p
–95
1p
–100
–75
–50
–25
0
+25
+50
+75
+100 +125
10
100
100k
Frequency (Hz)
CHANNEL-TO-CHANNEL ISOLATION
vs FREQUENCY
FEEDTHROUGH vs FREQUENCY
–20
0
–30
–10
–40
–20
–50
–30
Feedthrough (dB)
Crosstalk (dB)
10k
1k
Temperature (°C)
–60
–70
–80
–90
–40
–50
–60
–70
–80
–100
–110
–90
–120
–100
1k
10k
1M
100k
10M
1k
10k
1M
100k
Frequency (Hz)
10M
Frequency (Hz)
PSRR vs FREQUENCY
FREQUENCY RESPONSE
+30
70
CF = 0pF
+20
CF = 5pF
60
+10
50
0
40
PSRR (dB)
Gain (dB)
DAC Loaded w/0s
–10
CF = 10pF
–20
30
20
–30
10
–40
0
DAC Loaded w/1s
–10
–50
1k
10k
100k
1M
10M
DAC7800, 7801, 7802
SBAS005A
1k
10k
100k
1M
Frequency (Hz)
Frequency (Hz)
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7
DISCUSSION OF
SPECIFICATIONS
constant and can be driven by either a voltage or current, AC
or DC, positive or negative polarity, and have a voltage range
up to ±20V.
RELATIVE ACCURACY
This term, also known as end point linearity or integral
linearity, describes the transfer function of analog output to
digital input code. Relative accuracy describes the deviation
from a straight line, after zero and full-scale errors have been
adjusted to zero.
VREF A
R
2R
R
R
2R
2R
2R
2R
R RFB A
IOUT A
DIFFERENTIAL NONLINEARITY
Differential nonlinearity is the deviation from an ideal 1LSB
change in the output when the input code changes by 1LSB.
A differential nonlinearity specification of 1LSB maximum
ensures monotonicity.
AGND
DB11
(MSB)
DB10
DB9
DB0
(LSB)
FIGURE 1. Simplified Circuit Diagram for DAC A.
GAIN ERROR
Gain error is the difference between the full-scale DAC output
and the ideal value. The ideal full scale output value for the
DAC780x is –(4095/4096)VREF . Gain error may be adjusted
to zero using external trims, see Figures 5 and 7.
OUTPUT LEAKAGE CURRENT
The current which appears at IOUT A and IOUT B with the DAC
loaded with all zeros.
OUTPUT CAPACITANCE
The parasitic capacitance measured from IOUT A or IOUT B to
AGND.
CHANNEL-TO-CHANNEL ISOLATION
A CMOS switch transistor, included in series with the ladder
terminating resistor and in series with the feedback resistor,
RFB A, compensates for the temperature drift of the ON resistance of the ladder switches.
Figure 2 shows an equivalent circuit for DAC A. COUT is the
output capacitance due to the N-channel switches and varies
from about 30pF to 70pF with digital input code. The current
source ILKG is the combination of surface and junction leakages to the substrate. ILKG approximately doubles every 10°C.
RO is the equivalent output resistance of the DAC and it varies
with input code.
The AC output error due to capacitive coupling from DAC A
to DAC B or DAC B to DAC A.
R
RFB A
VREF A
MULTIPLYING FEEDTHROUGH ERROR
The AC output error due to capacitive coupling from VREF to
IOUT with the DAC loaded with all zeros.
R
DIN VREF
x
4096
R
RO
ILKG
IOUT A
COUT
AGND A
OUTPUT CURRENT SETTLING TIME
The time required for the output current to settle to within
+0.01% of final value for a full-scale step.
INSTALLATION
DIGITAL-TO-ANALOG GLITCH ENERGY
The integrated area of the glitch pulse measured in nanovoltseconds. The key contributor to DAC glitch is charge injected
by digital logic switching transients.
DIGITAL CROSSTALK
Glitch impulse measured at the output of one DAC but caused
by a full-scale transition on the other DAC. The integrated
area of the glitch pulse is measured in nanovolt-seconds.
CIRCUIT DESCRIPTION
Figure 1 shows a simplified schematic of one half of a DAC780x.
The current from the VREF A pin is switched between IOUT A and
AGND by 12 single-pole double-throw CMOS switches. This
maintains a constant current in each leg of the ladder regardless of the input code. The input resistance at VREF is therefore
8
FIGURE 2. Equivalent Circuit for DAC A.
ESD PROTECTION
All digital inputs of the DAC780x incorporate on-chip ESD
protection circuitry. This protection is designed to withstand
2.5kV (using the Human Body Model, 100pF and 1500Ω).
However, industry standard ESD protection methods should
be used when handling or storing these components. When
not in use, devices should be stored in conductive foam or
rails. The foam or rails should be discharged to the destination socket potential before devices are removed.
POWER-SUPPLY CONNECTIONS
The DAC780x are designed to operate on VDD = +5V +10%.
For optimum performance and noise rejection, power-supply
decoupling capacitors CD should be added as shown in the
application circuits. These capacitors (1µF tantalum recommended) should be located close to the DAC. AGND and
DAC7800, 7801, 7802
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SBAS005A
DGND should be connected together at one point only,
preferably at the power-supply ground point. Separate returns minimize current flow in low-level signal paths if properly
connected. Output op amp analog common (+ input) should
be connected as near to the AGND pins of the DAC780x as
possible.
DATA INPUT
ANALOG OUTPUT
MSB ↓
↓ LSB
1111 1111 1111
1000 0000 0000
0000 0000 0001
0000 0000 0000
–VREF (4095/4096)
–VREF (2048/4096) = –1/2VREF
–VREF (1/4096)
0 Volts
TABLE II. Unipolar Output Code.
WIRING PRECAUTIONS
To minimize AC feedthrough when designing a PC board,
care should be taken to minimize capacitive coupling between the VREF lines and the IOUT lines. Similarly, capacitive
coupling between DACs may compromise the channel-tochannel isolation. Coupling from any of the digital control or
data lines might degrade the glitch and digital crosstalk
performance. Solder the DAC780x directly into the PC board
without a socket. Sockets add parasitic capacitance (which
can degrade AC performance).
VDD VREF A
+5V
CD
1µF
+
RFB A
IOUT A
DAC A
DAC780X
IOUT B
DAC B
DGND
VREF B
VDD
+5V
CD
1µF
+
–
A2
+
VOUT B
A1, A2 OPA602 or 1/2 OPA2107.
DAC7802 has a single analog
common, AGND.
R1
100Ω
RFB A R2
IOUT A
DAC A
C1 10pF
–
A1
+
VOUT A
RFB B R4
DAC B
V REF B
DGND
47Ω
AGND A
IOUT B
R3
100Ω
47Ω
AGND B
C2 10pF
–
A2
+
VOUT B
A1, A2 OPA602 or 1/2 OPA2107.
DAC7802 has a single analog
common, AGND.
V IN B
FIGURE 4. Unipolar Configuration with Gain Trim.
The operational amplifiers used in this circuit can be single
amplifiers such as the OPA602, a dual amplifier such as the
OPA2107, or a quad amplifier like the OPA404. C1 and C2
provide phase compensation to minimize settling time and
overshoot when using a high speed operational amplifier. The
bipolar offset resistors R5–R7 and R8–R10 should be ratiomatched to 0.01% to ensure the specified gain error performance.
DAC7800, 7801, 7802
SBAS005A
AGND B
C2
10pF
VIN A
DAC780X
See Figure 5 for the DAC780x in a typical bipolar (fourquadrant) multiplying configuration. See Table III for the
listing of the analog output values versus digital input code.
VOUT A
V REF A
Figure 3 shows DAC780x in a typical unipolar (two-quadrant)
multiplying configuration. The analog output values versus
digital input code are listed in Table II. The operational
amplifiers used in this circuit can be single amplifiers such as
the OPA602, or a dual amplifier such as the OPA2107. C1
and C2 provide phase compensation to minimize settling time
and overshoot when using a high speed operational amplifier.
BIPOLAR CONFIGURATION
–
A1
+
FIGURE 3. Unipolar Configuration.
UNIPOLAR CONFIGURATION
If an application requires the DAC to have zero gain error, the
circuit shown in Figure 4 may be used. Resistors R2 and R4
induce a positive gain error greater than worst-case initial
negative gain error. Trim resistors R1 and R3 provide a
variable negative gain error and have sufficient trim range to
correct for the worst-case initial positive gain error plus the
error produced by R2 and R4.
AGND A
RFB B
AMPLIFIER OFFSET VOLTAGE
The output amplifier used with the DAC780x should have low
input offset voltage to preserve the transfer function linearity.
The voltage output of the amplifier has an error component
which is the offset voltage of the op amp multiplied by
the “noise gain” of the circuit. This “noise gain” is equal to
(RF /RO + 1) where RO is the output impedance of the DAC
IOUT terminal and RF is the feedback network impedance. The
nonlinearity occurs due to the output impedance varying with
code. If the 0 code case is excluded (where RO = infinity), the
RO will vary from R-3R providing a “noise gain” variation
between 4/3 and 2. In addition, the variation of RO is nonlinear
with code, and the largest steps in RO occur at major code
transitions where the worst differential nonlinearity is also
likely to be experienced. The nonlinearity seen at the amplifier
output is 2VOS – 4VOS /3 = 2VOS /3. Thus, to maintain good
nonlinearity the op amp offset should be much less than
1/2 LSB.
C1
10pF
www.ti.com
9
If an application requires the DAC to have zero gain error, the
circuit may be used, see Figure 6. Resistors R2 and R4 induce
a positive gain error greater than worst-case initial negative
gain error. Trim resistors R1 and R3 provide a variable
negative gain error and have sufficient trim range to correct
for the worst-case initial positive gain error plus the error
produced by R2 and R4.
DATA INPUT
ANALOG OUTPUT
MSB ↓
↓ LSB
1111 1111 1111
1000 0000 0001
1000 0000 0000
0111 1111 1111
0000 0000 0000
+VREF (2047/2048)
+VREF (1/2048)
0 Volts
–VREF (1/2048)
–VREF (2048/2048)
TABLE III. Bipolar Output Code.
R1
20k Ω
+5V
VDD VREF A
R2
20k Ω
–
CD +
1µF
A2
R3
10k Ω
VOUT A
+
RFB A
C1
10pF
IOUT A
DAC A
–
A1
AGND A
+
DAC7802 has a single analog common, AGND.
A1–A4, OPA602 or 1/2 OPA2107.
DAC780X
RFB B
C2
10pF
IOUT B
DAC B
AGND B
–
A3
+
R5
10k Ω
R6
20k Ω
R4
20k Ω
–
DGND
A4
VOUT B
+
VREF B
FIGURE 5. Bipolar Configuration.
APPLICATIONS
12-BIT PLUS SIGN DACS
For a bipolar DAC with 13 bits of resolution, two solutions are
possible. The addition of a precision difference amplifier and
a high speed JFET switch provides a 12-bit plus sign voltageoutput DAC, see Figure 7. When the switch selects the op
amp output, the difference amplifier serves as a noninverting
output buffer. If the analog ground side of the switch is
selected, the output of the difference amplifier is inverted.
Another option, see Figure 8, also produces a 12-bit plus sign
output without the additional switch and digital control line.
DIGITALLY PROGRAMMABLE ACTIVE FILTER
See Figure 9 for the DAC780x in a digitally programmable
active filter application. The design is based on the statevariable filter, Texas Instruments UAF42, an active filter topology that offers stable and repeatable filter characteristics.
10
DAC1 and DAC2 can be updated in parallel with a single word
to set the center frequency of the filter. DAC 4, which makes
use of the uncommitted op amp in UAF42, sets the Q of the
filter. DAC3 sets the gain of the filter transfer function without
changing the Q of the filter. The reverse is also true.
The center frequency is determined by fC = 1/2πRC where R is
the ladder resistance of the DAC (typical value, 10kΩ) and C
the internal capacitor value (1000pF) of the UAF42. External
capacitors can be added to lower the center frequency of the
filter. But the highest center frequency for this circuit will be
about 16kHz because the effective series resistance of the
DAC cannot be less than 10kΩ.
Note that the ladder resistance of the DAC may vary from
device to device. Thus, for best tracking, DAC2 and DAC3
should be in the same package. Some calibration may be
necessary from one filter to another.
DAC7800, 7801, 7802
www.ti.com
SBAS005A
R5
20k Ω
+5V
VDD VIN A
R6
20k Ω
–
CD +
1µF
+
VREF A
RFB A
R7
10k Ω
R2
47 Ω
C1
10pF
IOUT A
DAC A
RFB B
+
DAC7802 has a single analog common, AGND.
A1–A4, OPA602 or 1/2 OPA2107.
R4
47 Ω
C2
10pF
IOUT B
DAC B
–
A1
AGND A
DAC7802
AGND B
–
A3
+
R9
10kΩ
10k
Ω
R8
20k Ω
VREF B
R3
100 Ω
DGND
VOUT A
A2
R1
100 Ω
R10
20k Ω
–
VOUT B
A4
+
VIN B
FIGURE 6. Bipolar Configuration with Gain Trim.
+15V
2
+10V
6
REF102
+5V
4
VDD
CD
1µF
VREF A
RFB A
IOUT A
DAC A
AGND A
C1
10pF
R
A1
R
2
DAC780X
6
R
±10V
13 Bits
3
R
Sign Control
DAC B
DGND
VREF B
DG188
AGND B
1
INA105
DAC7802 has a single analog common, AGND.
A1 OPA602 or 1/2 OPA2107.
FIGURE 7. 12-Bit Plus Sign DAC.
DAC7800, 7801, 7802
SBAS005A
www.ti.com
11
+15V
2
+10V
6
REF102
+5V
4
VDD
CD
1µF
VREF A
RFB A
C1
10pF
IOUT A
DAC A
R
A1
AGND A
R
2
DAC780X
DGND
R
INA105
A2
AGND B
VREF B
±10V
13 Bits
3
C2
10pF
IOUT B
DAC B
6
R
RFB B
1
DAC7802 has a single analog common, AGND.
A1 OPA602 or 1/2 OPA2107.
FIGURE 8. 13-Bit Bipolar DAC.
Q Adjust
VREF 2
DAC 2
f C Adjust
V REF 4
IOUT 2
DAC 4
AGND 2
VREF 1
I OUT 4
AGND 4
1/2 DAC780X
IOUT 1
DAC 1
R FB 4
AGND 1
DAC780X
High-Pass Out
Filter Input
13
R
Low-Pass
Out
Band-Pass
Out
8
7
1
14
5
VREF 3
I OUT 3
DAC 3
C
R
C
12
AGND 3
1/2 DAC780X
Gain Adjust
6
3
R
R
UAF 42
R = 50k Ω ±0.5%
C = 1000pF ±0.5%
11
2
4
FIGURE 9. Digitally Programmable Universal Active Filter.
12
DAC7800, 7801, 7802
www.ti.com
SBAS005A
PACKAGE DRAWINGS
MPDI002B – JANUARY 1995 – REVISED FEBRUARY 2000
N (R-PDIP-T**)
PLASTIC DUAL-IN-LINE PACKAGE
16 PINS SHOWN
PINS **
14
16
18
20
A MAX
0.775
(19,69)
0.775
(19,69)
0.920
(23,37)
0.975
(24,77)
A MIN
0.745
(18,92)
0.745
(18,92)
0.850
(21,59)
0.940
(23,88)
DIM
A
16
9
0.260 (6,60)
0.240 (6,10)
1
8
0.070 (1,78) MAX
0.035 (0,89) MAX
0.325 (8,26)
0.300 (7,62)
0.020 (0,51) MIN
0.015 (0,38)
Gauge Plane
0.200 (5,08) MAX
Seating Plane
0.010 (0,25) NOM
0.125 (3,18) MIN
0.100 (2,54)
0.021 (0,53)
0.015 (0,38)
0.430 (10,92) MAX
0.010 (0,25) M
14/18 PIN ONLY
4040049/D 02/00
NOTES: A. All linear dimensions are in inches (millimeters).
B. This drawing is subject to change without notice.
C. Falls within JEDEC MS-001 (20-pin package is shorter than MS-001).
DAC7800, 7801, 7802
SBAS005A
www.ti.com
13
PACKAGE DRAWINGS (Cont)
MSOI003E – JANUARY 1995 – REVISED SEPTEMBER 2001
DW (R-PDSO-G**)
PLASTIC SMALL-OUTLINE PACKAGE
16 PINS SHOWN
0.050 (1,27)
0.020 (0,51)
0.014 (0,35)
16
0.010 (0,25) M
9
0.419 (10,65)
0.400 (10,15)
0.010 (0,25) NOM
0.299 (7,59)
0.291 (7,39)
Gage Plane
0.010 (0,25)
1
8
0.050 (1,27)
0.016 (0,40)
0 ñ8
A
Seating Plane
0.104 (2,65) MAX
0.012 (0,30)
0.004 (0,10)
PINS **
0.004 (0,10)
16
18
20
24
28
A MAX
0.410
(10,41)
0.462
(11,73)
0.510
(12,95)
0.610
(15,49)
0.710
(18,03)
A MIN
0.400
(10,16)
0.453
(11,51)
0.500
(12,70)
0.600
(15,24)
0.700
(17,78)
DIM
4040000 / E 08/01
NOTES: A.
B.
C.
D.
14
All linear dimensions are in inches (millimeters).
This drawing is subject to change without notice.
Body dimensions do not include mold flash or protrusion not to exceed 0.006 (0,15).
Falls within JEDEC MS-013
DAC7800, 7801, 7802
www.ti.com
SBAS005A
PACKAGE DRAWINGS (Cont)
MPDI004 – OCTOBER 1994
NT (R-PDIP-T**)
PLASTIC DUAL-IN-LINE PACKAGE
24 PINS SHOWN
PINS **
A
24
28
A MAX
1.260
(32,04)
1.425
(36,20)
A MIN
1.230
(31,24)
1.385
(35,18)
B MAX
0.310
(7,87)
0.315
(8,00)
B MIN
0.290
(7,37)
0.295
(7,49)
DIM
24
13
0.280 (7,11)
0.250 (6,35)
1
12
0.070 (1,78) MAX
B
0.020 (0,51) MIN
0.200 (5,08) MAX
Seating Plane
0.125 (3,18) MIN
0.100 (2,54)
0.021 (0,53)
0.015 (0,38)
0°– 15°
0.010 (0,25) M
0.010 (0,25) NOM
4040050 / B 04/95
NOTES: A. All linear dimensions are in inches (millimeters).
B. This drawing is subject to change without notice.
DAC7800, 7801, 7802
SBAS005A
www.ti.com
15
PACKAGE DRAWINGS (Cont)
MPDI066 – AUGUST 2001
NTG (R-PDIP-T24)
PLASTIC DUAL-IN-LINE
1.195 (30,35)
1.160 (29,46)
D
24
13
0.280 (7,11)
0.240 (6,10)
1
D
1
2
Index
Area
0.195 (4,95)
0.115 (2,92)
0.070 (1,78)
0.045 (1,14)
Base Plane
H
–C–
0.325 (8,26)
0.300 (7,62)
0.210 (5,33)
MAX
C
E
Seating Plane
E
0.005 (0,13) MIN
D
1/2 Lead 4 PL
0.150 (3,81)
0.115 (2,92) C
0.100 (2,54)
0.045 (1,14) 4 PL
H
0.030 (0,76)
0.015 (0,38)
MIN
C
0.022 (0,56)
0.014 (0,36)
0.010 (0,25) M
C
0.300 (7,62)
0.014 (0,36)
0.008 (0,20)
0.060 (1,52)
0.000 (0,00) F
0.430 (10,92)
MAX
F
4202642/A 08/01
NOTES: A. All linear dimensions are in inches (millimeters).
B. This drawing is subject to change without notice.
C. Dimensions are measured with the package
seated in JEDEC seating plane gauge GS-3.
D. Dimensions do not include mold flash or protrusions.
Mold flash or protrusions shall not exceed 0.010 (0,25).
E. Dimensions measured with the leads constrained to be
perpendicular to Datum C.
F. Dimensions are measured at the lead tips with the
leads unconstrained.
G. Pointed or rounded lead tips are preferred to ease
insertion.
H. Maximum dimensions do not include dambar
protrusions. Dambar protrusions shall not exceed
0.010 (0,25).
16
I. Distance between leads including dambar protrusions
to be 0.005 (0,13) minumum.
J. A visual index feature must be located within the
cross–hatched area.
K. For automatic insertion, any raised irregularity on the
top surface (step, mesa, etc.) shall be symmetrical
about the lateral and longitudinal package centerlines.
L. Controlling dimension in inches.
M. Falls within JEDEC MS-011-AB.
DAC7800, 7801, 7802
www.ti.com
SBAS005A
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