AD DAC8562EP 5 volt, parallel input complete 12-bit dac Datasheet

a
+5 Volt, Parallel Input
Complete 12-Bit DAC
DAC8562
FEATURES
Complete 12-Bit DAC
No External Components
Single +5 Volt Operation
1 mV/Bit with 4.095 V Full Scale
True Voltage Output, 65 mA Drive
Very Low Power –3 mW
FUNCTIONAL BLOCK DIAGRAM
DAC-8562
Included on the chip, in addition to the DAC, is a rail-to-rail
amplifier, latch and reference. The reference (REFOUT) is
trimmed to 2.5 volts, and the on-chip amplifier gains up the
DAC output to 4.095 volts full scale. The user needs only supply a +5 volt supply.
The DAC8562 is coded straight binary. The op amp output
swings from 0 to +4.095 volts for a one millivolt per bit resolution, and is capable of driving ± 5 mA. Built using low temperature-coefficient silicon-chrome thin-film resistors, excellent
linearity error over temperature has been achieved as shown below in the linearity error versus digital input code plot.
Digital interface is parallel and high speed to interface to the
fastest processors without wait states. The interface is very simple requiring only a single CE signal. An asynchronous CLR input sets the output to zero scale.
VOUT
12
AGND
DAC REGISTER
12
DGND
CE
DATA
CLR
The DAC8562 is available in two different 20-pin packages,
plastic DIP and SOL-20. Each part is fully specified for operation over –40°C to +85°C, and the full +5 V ± 5% power supply
range.
For MIL-STD-883 applications, contact your local ADI sales
office for the DAC8562/883 data sheet which specifies operation over the –55°C to +125°C temperature range.
1
VDD = +5V
0.75
LINEARITY ERROR — LSB
The DAC8562 is a complete, parallel input, 12-bit, voltage output DAC designed to operate from a single +5 volt supply. Built
using a CBCMOS process, these monolithic DACs offer the
user low cost, and ease-of-use in +5 volt only systems.
12-BIT
DAC
REF
APPLICATIONS
Digitally Controlled Calibration
Servo Controls
Process Control Equipment
PC Peripherals
GENERAL DESCRIPTION
VDD
REFOUT
TA = –55°C, +25°C, +125°C
0.5
–55°C
0.25
0
–0.25
–0.5
+25°C & +125°C
–0.75
–1
0
1024
2048
3072
DIGITAL INPUT CODE — Decimal
4096
Figure 1. Linearity Error vs. Digital Input Code Plot
REV. A
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700
Fax: 617/326-8703
DAC8562–SPECIFICATIONS
ELECTRICAL CHARACTERISTICS
(@ VDD = +5.0 6 5%, RS = No Load, –408C ≤ TA ≤ +858C, unless otherwise noted)
Parameter
Symbol
Condition
Min
STATIC PERFORMANCE
Resolution
Relative Accuracy
N
INL
Differential Nonlinearity
Zero-Scale Error
Full-Scale Voltage
DNL
VZSE
VFS
12
–1/2
–1
–1
TCVFS
Note 2
E Grade
F Grade
No Missing Codes
Data = 000H
Data - FFFH3
E Grade
F Grade
Notes 3, 4
ANALOG OUTPUT
Output Current
Load Regulation at Half Scale
Capacitive Load
IOUT
LDREG
CL
Data = 800H
RL = 402 Ω to ∞, Data = 800H
No Oscillation4
REFERENCE OUTPUT
Output Voltage
Output Source Current
Line Rejection
Load Regulation
VREF
IREF
LNREJ
LDREG
LOGIC INPUTS
Logic Input Low Voltage
Logic Input High Voltage
Input Leakage Current
Input Capacitance
VIL
VIH
IIL
CIL
INTERFACE TIMING SPECIFICATIONS1, 4
Chip Enable Pulse Width
Data Setup
Data Hold
Clear Pulse Width
tCEW
tDS
tDH
tCLRW
Full-Scale Tempco
AC CHARACTERISTICS4
Voltage Output Settling Time6
Digital Feedthrough
SUPPLY CHARACTERISTICS
Positive Supply Current
Note 5
Typ
Max
Units
± 1/4
± 3/4
± 3/4
+1/2
+1/2
+1
+1
+3
Bits
LSB
LSB
LSB
LSB
4.087
4.079
4.095
4.095
± 16
4.103
4.111
±5
±7
1
500
2.484
5
2.500
7
0.8
2.4
10
10
Note 4
30
30
10
20
16
35
IDD
VIH = 2.4 V, VIL = 0.8 V
VIL = 0 V, VDD = +5 V
VIH = 2.4 V, VIL = 0.8 V
VIL = 0 V, VDD = +5V
∆VDD = ± 5%
3
0.6
15
3
0.002
Power Supply Sensitivity
PSS
mA
LSB
pF
V
mA
%/V
%/mA
V
V
µA
pF
ns
ns
ns
ns
To ± 1 LSB of Final Value
PDISS
2.516
0.08
0.1
IREF = 0 to 5 mA
tS
Power Dissipation
3
V
V
ppm/°C
µs
nV sec
6
1
30
5
0.004
mA
mA
mW
mW
%/%
NOTES
1
All input control signals are specified with t r = tf = 5 ns (10% to 90% of +5 V) and timed from a voltage level of 1.6 V.
2
1 LSB = 1 mV for 0 to +4.095 V output range.
3
Includes internal voltage reference error.
4
These parameters are guaranteed by design and not subject to production testing.
5
Very little sink current is available at the REFOUT pin. Use external buffer if setting up a virtual ground.
6
The settling time specification does not apply for negative going transitions within the last 6 LSBs of ground. Some devices exhibit double the typical settling time in
this 6 LSB region.
Specifications subject to change without notice.
–2–
REV. A
DAC8562
(@ VDD = +5.0 V 6 5%, RL = No Load, TA = +258C, applies to part number DAC8562GBC only,
WAFER TEST LIMITS unless otherwise noted)
Parameter
Symbol
Condition
STATIC PERFORMANCE
Relative Accuracy
Differential Nonlinearity
Zero-Scale Error
Full-Scale Voltage
Reference Output Voltage
INL
DNL
VZSE
VFS
VREF
No Missing Codes
Data = 000H
Data = FFFH
LOGIC INPUTS
Logic Input Low Voltage
Logic Input High Voltage
Input Leakage Current
VIL
VIH
IIL
SUPPLY CHARACTERISTICS
Positive Supply Current
IDD
Power Dissipation
PDISS
Power Supply Sensitivity
PSS
Min
Typ
Max
Units
–1
–1
± 3/4
± 3/4
+1/2
4.095
2.500
+1
+1
+3
4.105
2.510
LSB
LSB
LSB
V
V
0.8
10
V
V
µA
6
1
30
5
0.004
mA
mA
mW
mW
%/%
4.085
2.490
2.4
VIH = 2.4 V, VIL = 0.8 V
VIL = 0 V, VDD = +5 V
VIH = 2.4 V, VIL = 0.8 V
VIL = 0 V, VDD = +5 V
∆VDD = ± 5%
3
0.6
15
3
0.002
NOTE
1
Electrical tests are performed at wafer probe to the limits shown. Due to variations in assembly methods and normal yield loss, yield after packaging is not guaranteed
for standard product dice. Consult factory to negotiate specifications based on dice lot qualifications through sample lot assembly and testing.
ABSOLUTE MAXIMUM RATINGS*
tCEW
1
VDD to DGND and AGND . . . . . . . . . . . . . . . . –0.3 V, +10 V
Logic Inputs to DGND . . . . . . . . . . . . . . . –0.3 V, VDD + 0.3 V
VOUT to AGND . . . . . . . . . . . . . . . . . . . . . –0.3 V, VDD + 0.3 V
VREFOUT to AGND . . . . . . . . . . . . . . . . . . –0.3 V, VDD + 0.3 V
AGND to DGND . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V, VDD
IOUT Short Circuit to GND . . . . . . . . . . . . . . . . . . . . . . 50 mA
Package Power Dissipation . . . . . . . . . . . . . . (TJ max – TA)/uJA
Thermal Resistance uJA
20-Pin Plastic DIP Package (P) . . . . . . . . . . . . . . . . 74°C/W
20-Lead SOIC Package (S) . . . . . . . . . . . . . . . . . . . 89°C/W
Maximum Junction Temperature (TJ max) . . . . . . . . . . 150°C
Operating Temperature Range . . . . . . . . . . . . . –40°C to +85°C
Storage Temperature Range . . . . . . . . . . . . . –65°C to +150°C
Lead Temperature (Soldering, 10 secs) . . . . . . . . . . . . +300°C
CE
0
tDS
tDH
1
DB11–0
DATA VALID
0
tCLRW
1
CLR
0
FS
±1 LSB
ERROR BAND
VOUT
ZS
tS
tS
Figure 2. Timing Diagram
Table I. Control Logic Truth Table
*Stresses above those listed under “Absolute Maximum Ratings” may cause
permanent damage to the device. This is a stress rating only and functional
operation of the device at these or any other conditions above those indicated in the
operational sections of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
CE
CLR
DAC Register Function
H
L
↑+
X
H
H
H
H
L
↑+
Latched
Transparent
Latched with New Data
Loaded with All Zeros
Latched All Zeros
↑ + Positive Logic Transition; X Don't Care.
CAUTION
ESD (electrostatic discharge) sensitive device. The digital control inputs are diode protected;
however, permanent damage may occur on unconnected devices subject to high energy electrostatic
fields. Unused devices must be stored in conductive foam or shunts. The protective foam should be
discharged to the destination socket before devices are inserted.
REV. A
–3–
WARNING!
ESD SENSITIVE DEVICE
DAC8562
Table II. Nominal Output Voltage vs. Input Code
PIN CONFIGURATIONS
20-Pin P-DIP
(N-20)
SOL-20
(R-20)
1
DB3
1
20 VDD
DB4
2
19
DB5
3
18 DB1
DAC-8562
DB6
4
17
DB0
TOP VIEW
(Not to Scale)
DB7
5
DAC-8562
16
CE
DB8
6
TOP VIEW
(Not to Scale)
15
CLR
DB9
7
14 REFOUT
DB2
DB10
8
13
VOUT
DB11
9
12
AGND
DGND
10
11
NC
Binary
Hex
Decimal
Output (V)
0000 0000 0000
0000 0000 0001
0000 0000 0010
0000 0000 1111
0000 0001 0000
0000 1111 1111
0001 0000 0000
0001 1111 1111
0010 0000 0000
0011 1111 1111
0100 0000 0000
0111 1111 1111
1000 0000 0000
1100 0000 0000
1111 1111 1111
000
001
002
00F
010
0FF
100
1FF
200
3FF
400
7FF
800
C00
FFF
0
1
2
15
16
255
256
511
512
1023
1024
2047
2048
3072
4095
0.000 Zero Scale
0.001
0.002
0.015
0.016
0.255
0.256
0.511
0.512
1.023
1.024
2.047
2.048 Half Scale
3.072
4.095 Full Scale
NC = NO CONNECT
PIN DESCRIPTIONS
ORDERING GUIDE
Model
INL
(LSB)
Temperature
Range
Package
Option
DAC8562EP
DAC8562FP
DAC8562FS
DAC8562GBC
± 1/2
±1
±1
±1
–40°C to +85°C
–40°C to +85°C
–40°C to +85°C
+25°C
N-20
N-20
R-20
Dice
Pin
Name
Description
20
VDD
1-9
17-19
16
15
DB0-DB11
8
12
DGND
AGND
13
VOUT
14
REFOUT
11
NC
Positive supply. Nominal value
+5 volts, ± 5%.
Twelve Binary Data Bit inputs. DB11
is the MSB and DB0 is the LSB.
Chip Enable. Active low input.
Active low digital input that clears the
DAC register to zero, setting the DAC
to minimum scale.
Digital ground for input logic.
Analog Ground. Ground reference for
the internal bandgap reference voltage,
the DAC, and the output buffer.
Voltage output from the DAC. Fixed
output voltage range of 0 V to 4.095 V
with 1 mV/LSB. An internal temperature stabilized reference maintains a
fixed full-scale voltage independent of
time, temperature and power supply
variations.
Nominal 2.5 V reference output voltage. This node must be buffered if required to drive external loads.
No Connection. Leave pin floating.
CE
CLR
DICE CHARACTERISTICS
VOUT
REFOUT
DGND
DB11
12
10
9
8
13
DB10
14
CLR
15
CE
16
DB0
17
DB1
AGND
7
DB9
6
DB8
5
DB7
4
DB6
3
18
19
20
1
2
DB2
VDD
DB3
DB4
DB5
SUBSTRATE IS COMMON WITH VDD.
TRANSISTOR COUNT: 524
DIE SIZE: 0.70 X 0.105 INCH; 7350 SQ MILS
–4–
REV. A
DAC8562
current is provided by a P channel pull-up device that can supply GND terminated loads, especially important at the –5%
supply tolerance value of 4.75 volts.
OPERATION
The DAC8562 is a complete ready to use 12-bit digital-toanalog converter. Only one +5 V power supply is necessary for
operation. It contains a voltage-switched, 12-bit, laser-trimmed
digital-to-analog converter, a curvature-corrected bandgap reference, a rail-to-rail output op amp, and a DAC register. The parallel data interface consists of 12 data bits, DB0–DB11, and a
active low CE strobe. In addition, an asynchronous CLR pin
will set all DAC register bits to zero causing the VOUT to become zero volts. This function is useful for power on reset or
system failure recovery to a known state.
VDD
P-CH
VOUT
N-CH
D/A CONVERTER SECTION
The internal DAC is a 12-bit voltage-mode device with an output that swings from AGND potential to the 2.5 volt internal
bandgap voltage. It uses a laser trimmed R-2R ladder which is
switched by N channel MOSFETs. The output voltage of the
DAC has a constant resistance independent of digital input
code. The DAC output (not available to the user) is internally
connected to the rail-to-rail output op amp.
AGND
Figure 4. Equivalent Analog Output Circuit
Figures 5 and 6 in the typical performance characteristics section provide information on output swing performance near
ground and full scale as a function of load. In addition to resistive load driving capability, the amplifier has also been carefully
designed and characterized for up to 500 pF capacitive load
driving capability.
AMPLIFIER SECTION
The internal DAC’s output is buffered by a low power consumption precision amplifier. This low power amplifier contains
a differential PNP pair input stage which provides low offset
voltage and low noise, as well as the ability to amplify the zeroscale DAC output voltages. The rail-to-rail amplifier is configured in a gain of 1.6384 (= 4.095 V/2.5 V) in order to set the
4.095 volt full-scale output (1 mV/LSB). See Figure 3 for an
equivalent circuit schematic of the analog section.
REFOUT
2.5V
VOLTAGE SWITCHED 12-BIT
R-2R D/A CONVERTER
BANDGAP
REFERENCE
REFERENCE SECTION
The internal 2.5 V curvature-corrected bandgap voltage reference is laser trimmed for both initial accuracy and low temperature coefficient. The voltage generated by the reference is
available at the REFOUT pin. Since REFOUT is not intended
to drive external loads, it must be buffered–refer to the applications section for more information. The equivalent emitter follower output circuit of the REFOUT pin is shown in Figure 3.
Bypassing the REFOUT pin is not required for proper operation. Figure 7 shows broadband noise performance.
RAIL-TO-RAIL
OUTPUT
AMPLIFIER
2R
POWER SUPPLY
R
The very low power consumption of the DAC8562 is a direct
result of a circuit design optimizing use of the CBCMOS process. By using the low power characteristics of the CMOS for
the logic, and the low noise, tight matching of the complementary bipolar transistors, good analog accuracy is achieved.
VOUT
BUFFER
R2
2R
R1
R
2R
SPDT
N ch FET
SWITCHES
AV = 4.096/2.5
= 1.636V/V
For power-consumption sensitive applications it is important to
note that the internal power consumption of the DAC8562 is
strongly dependent on the actual logic-input voltage-levels
present on the DB0–DB11, CE and CLR pins. Since these inputs are standard CMOS logic structures, they contribute static
power dissipation dependent on the actual driving logic VOH and
VOL voltage levels. The graph in Figure 9 shows the effect on total DAC8562 supply current as a function of the actual value of
input logic voltage. Consequently for optimum dissipation use
of CMOS logic versus TTL provides minimal dissipation in the
static state. A VINL = 0 V on the DB0–DB11 pins provides the
lowest standby dissipation of 600 µA with a +5 V power supply.
2R
2R
Figure 3. Equivalent DAC8562 Schematic of
Analog Portion
The op amp has a 16 µs typical settling time to 0.01%. There
are slight differences in settling time for negative slewing signals
versus positive. See the oscilloscope photos in the Typical Performances section of this data sheet.
OUTPUT SECTION
The rail-to-rail output stage of this amplifier has been designed
to provide precision performance while operating near either
power supply. Figure 4 shows an equivalent output schematic of
the rail-to-rail amplifier with its N channel pull down FETs that
will pull an output load directly to GND. The output sourcing
REV. A
–5–
DAC8562
As with any analog system, it is recommended that the
DAC8562 power supply be bypassed on the same PC card that
contains the chip. Figure 10 shows the power supply rejection
versus frequency performance. This should be taken into account when using higher frequency switched-mode power supplies with ripple frequencies of 100 kHz and higher.
TIMING AND CONTROL
The DAC8562 has a 12-bit DAC register that simplifies interface to a 12-bit (or wider) data bus. The latch is controlled by
the Chip Enable (CE) input. If the application does not involve
a data bus, wiring CE low allows direct operation of the DAC.
The data latch is level triggered and acquires data from the data
bus during the time period when CE is low. When CE goes
high, the data is latched into the register and held until CE returns low. The minimum time required for the data to be
present on the bus before CE returns high is called the data
setup time (tDS) as seen in Figure 2. The data hold time (tDH) is
the amount of time that the data has to remain on the bus after
CE goes high. The high speed timing offered by the DAC8562
provides for direct interface with no wait states in all but the
fastest microprocessors.
One advantage of the rail-to-rail output amplifier used in the
DAC8562 is the wide range of usable supply voltage. The part is
fully specified and tested over temperature for operation from
+4.75 V to +5.25 V. If reduced linearity and source current capability near full scale can be tolerated, operation of the
DAC8562 is possible down to +4.3 volts. The minimum operating supply voltage versus load current plot, in Figure 11, provides information for operation below VDD = +4.75 V.
Typical Performance Characteristics
5
100
RL
R
TIED TO
TO AGND
AGND
L TIED
DATA
D = FFFH
= FFFH
3
2
1
RL TIED TO +5V
DATA = 000H
0
10
100
1k
10k
LOAD RESISTANCE – Ω
100k
TA = +85°C
TA = +25°C
0.1
0.01
1
10
100
OUTPUT SINK CURRENT – µA
10
0%
TA = 25°C
NBW = 630kHz
DATA = 800H
RL TIED TO +2V
0
–20
–40
–60
–100
1000
Figure 6. Pull-Down Voltage vs.
Output Sink Current Capability
NEG
CURRENT
LIMIT
1
2
3
OUTPUT VOLTAGE – Volts
Figure 7. IOUT vs. VOUT
5
100
90
20
–80
100
1ms
50mV
40
TA = –40°C
POWER SUPPLY REJECTION – dB
OUTPUT NOISE VOLTAGE – 500µV/DIV
Figure 5. Output Swing vs. Load
10
1
POS0
CURRENT0
LIMIT0
60
OUTPUT CURRENT – mA
OUTPUT PULLDOWN VOLTAGE – mV
4
80
VDD = +5V
DATA = 000H
SUPPLY CURRENT – mA
OUTPUT VOLTAGE – Volts
VDD = +5V
TA = +25°C
VDD = +5V
4
TA = +25°C
3
2
1
VDD = +5V ±200mV AC
TA = +25°C
DATA = FFFH
80
60
40
20
TIME = 1ms/DIV
0
Figure 8. Broadband Noise
0
1
2
3
4
LOGIC VOLTAGE VALUE – Volts
5
Figure 9. Supply Current vs. Logic
Input Voltage
–6–
0
10
100
1k
10k
FREQUENCY – Hz
100k
Figure 10. Power Supply Rejection
vs. Frequency
REV. A
DAC8562
5.0
0
5
100
0
OUTPUT
DATA = 204810 TO 204710
2.048
PROPER OPERATION
WHEN VDD SUPPLY
VOLTAGE ABOVE
CURVE
4.4
90
VDD = +5V
4
4.6
VOUT – Volts
VDD MIN – Volts
CE
∆VFS ≤ 1 LSB
DATA = FFFH
TA = +25°C
4.8
5V
INPUT
5
4.2
2.038
TA = +25°C
3
2
1
10
0%
2.028
0
20µs
1V
2.018
TIME = 20µs/DIV
4.0
0.01
0.04 0.1
1.0
0.4
4.0
OUTPUT LOAD CURRENT – mA
TIME – 200ns/DIV
10
Figure 11. Minimum Supply
Voltage vs. Load
Figure 12. Midscale Transition
Performance
Figure 13. Large Signal Settling
Time
16µs
5
0
OUTPUT VOLTAGE
1mV/DIV
0
VDD = +5V
TA = +25°C
VDD = +5V
1.5
LINEARITY ERROR – LSB
DATA
5
OUTPUT VOLTAGE
1mV/DIV
DATA
2.0
VDD = +5V
TA = +25°C
16µs
TA = –40°C, 25°C, +85°C
1.0
–40°C
0.5
0.0
–0.5
+25°C & +85°C
–1.0
–1.5
–2.0
TIME – 10µs/DIV
TIME – 10µs/DIV
0
512 1024 1536 2048 2560 3072 3584 4096
DIGITAL INPUT CODE – Decimal
Figure 14. Output Voltage Rise
Time Detail
30
20
10
0
–8 –6 –4 –2 0 2 4 6 8 10 12 14 16
TOTAL UNADJUSTED ERROR – LSB
Figure 17. Total Unadjusted
Error Histogram
REV. A
4.115
3
VDD = +5V
NO LOAD
SS = 300 PCS
DATA = 000H
NO LOAD
VDD = +5.0V
2
ZERO-SCALE – mV
NUMBER OF UNITS
40
4.125
TUE = Σ INL+ZS+FS
SS = 300 UNITS
TA = +25°C
FULL-SCALE OUTPUT –Volts
50
Figure 16. Linearity Error vs.
Digital Code
Figure 15. Output Voltage Fall
Time Detail
AVG +1σ
4.105
AVG
4.095
AVG –1σ
1
0
4.085
4.075
–50
–25
0
25
50
75
100
TEMPERATURE – °C
Figure 18. Full-Scale Voltage
vs. Temperature
–7–
125
–1
–50
–25
0
25
50
75
TEMPERATURE – °C
100
125
Figure 19. Zero-Scale Voltage vs.
Temperature
DAC8562
DAC8562–Typical
Performance Characteristics
8
5
VDD = +5V
TA = 25°C
DATA = FFFH
1
0.1
VDD = +5V
DATA = FFF
4
READINGS NORMALIZED
TO ZERO HOUR TIME POINT
2
1
0
RANGE
–1
AVG
–2
–3
1k
10k
100
FREQUENCY – Hz
VDD = +5.0V
4
VDD = +5.25V
3
2
135 UNITS TESTED
200
400
600
800
1000
HOURS OF OPERATION AT +125°C
0
Figure 20. Output Voltage Noise
Density vs. Frequency
5
VDD = +4.75V
0
–50
–5
100k
6
1
–4
0.01
10
VDATA = +2.4V
NO LOAD
7
H
3
SUPPLY CURRENT – mA
OUTPUT VOLTAGE CHANGE – mV
OUTPUT NOISE DENSITY – µV/ Hz
10
1200
Figure 21. Long-Term Drift
Accelerated by Burn-In
–25
0
25
50
75
TEMPERATURE – °C
100
125
Figure 22. Supply Current vs.
Temperature
10
A4 0.040 V
100
90
13.82 µs
1
8
AVG +1σ
CE = HIGH
100
0
6
90
TA = +25°C
RL = ∞
VDD
VOUT
5mV/DIV
0V
VREF
0V
DLY
VREF OUT ERROR –mV
DATA
2V
10
10
0%
0%
5mV
5V
1µs
2V
Bw
L
X
2
0
AVG –1σ
–2
–4
–6
5µs
–8
TIME = 20µs/DIV
TIME = 1µs/DIV
4
VDD = +5V
SAMPLE SIZE = 300
–10
–50
–25
0
25
50
75
100
125
TEMPERATURE – °C
Figure 23. Reference Startup vs.
Time
Figure 24. Digital Feedthrough vs.
Time
0.004
0.003
0.10
REF LINE REGULATION – %/Volt
REF LOAD REGULATION – %/mA
0.005
AVG + 3 σ
AVG
AVG – 3σ
0.002
0.001
0.000
–50
Figure 25. Reference Error vs.
Temperature
VDD = +5V
∆ IL = 5mA
SAMPLE SIZE = 302 PCS
–25
25
50
75
0
TEMPERATURE – °C
100
0.06
AVG + 3 σ
AVG
0.04
AVG – 3 σ
0.02
0.00
–50
125
VDD = +4.75 TO +5.25V
SAMPLE SIZE = 302 PCS
0.08
–25
0
25
50
75
100
125
TEMPERATURE – °C
Figure 26. Reference Load
Regulation vs. Temperature
Figure 27. Reference Line
Regulation vs. Temperature
–8–
REV. A
DAC8562
APPLICATIONS SECTION
Power Supplies, Bypassing, and Grounding
The DAC8562 includes two ground connections in order to
minimize system accuracy degradation arising from grounding
errors. The two ground pins are designated DGND (Pin 10)
and AGND (Pin 12). The DGND pin is the return for the digital circuit sections of the DAC and serves as their input threshold reference point. Thus DGND should be connected to the
same ground as the circuitry that drives the digital inputs.
All precision converter products require careful application of
good grounding practices to maintain full-rated performance.
Because the DAC8562 has been designed for +5 V applications,
it is ideal for those applications under microprocessor or microcomputer control. In these applications, digital noise is prevalent; therefore, special care must be taken to assure that its
inherent precision is maintained. This means that particularly
good engineering judgment should be exercised when addressing the power supply, grounding, and bypassing issues using the
DAC8562.
Pin 12, AGND, serves as the supply rail for the internal voltage
reference and the output amplifier. This pin should also serve as
the reference point for all analog circuitry associated with the
DAC8562. Therefore, to minimize any errors, it is recommended that the AGND connection of the DAC8562 be connected to a high quality analog ground. If the system contains
any analog signal path carrying a significant amount of current,
then that path should have its own return connection to Pin 12.
The power supply used for the DAC8562 should be well filtered
and regulated. The device has been completely characterized for
a +5 V supply with a tolerance of ± 5%. Since a +5 V logic supply is almost universally available, it is not recommended to
connect the DAC directly to an unfiltered logic supply without
careful filtering. Because it is convenient, a designer might be
inclined to tap a logic circuit s supply for the DAC’s supply.
Unfortunately, this is not wise because fast logic with nanosecond transition edges induces high current pulses. The high transient current pulses can generate glitches hundreds of millivolts
in amplitude due to wiring resistances and inductances. This
high frequency noise will corrupt the analog circuits internal to
the DAC and cause errors. Even though their spike noise is
lower in amplitude, directly tapping the output of a +5 V system
supplies can cause errors because these supplies are of the
switching regulator type that can and do generate a great deal of
high frequency noise. Therefore, the DAC and any associated
analog circuitry should be powered directly from the system
power supply outputs using appropriate filtering. Figure 28
illustrates how a clean, analog-grade supply can be generated
from a +5 V logic supply using a differential LC filter with separate power supply and return lines. With the values shown, this
filter can easily handle 100 mA of load current without saturating the ferrite cores. Higher current capacity can be achieved
with larger ferrite cores. For lowest noise, all electrolytic capacitors should be low ESR (Equivalent Series Resistance) type.
FERRITE BEADS:
2 TURNS, FAIR-RITE
#2677006301
TTL/CMOS
LOGIC
CIRCUITS
100µF
ELECT.
It is often advisable to maintain separate analog and digital
grounds throughout a complete system, tying them common to
one place only. If the common tie point is remote and an accidental disconnection of that one common tie point were to
occur due to card removal with power on, a large differential
voltage between the two commons could develop. To protect
devices that interface to both digital and analog parts of the system, such as the DAC8562, it is recommended that the common ground tie points be provided at each such device. If only
one system ground can be connected directly to the DAC8562,
it recommended that the analog common be used. If the
system’s AGND has suitably low impedance, then the digital
signal currents flowing in it should not seriously affect the
ground noise. The amount of digital noise introduced by connecting the two grounds together at the device will not adversely
affect system performance due to loss of digital noise immunity.
Generous bypassing of the DAC’s supply goes a long way in reducing supply line-induced errors. Local supply bypassing consisting of a 10 µF tantalum electrolytic in parallel with a 0.1 µF
ceramic is recommended. The decoupling capacitors should be
connected between the DAC’s supply pin (Pin 20) and the analog ground (Pin 12). Figure 29 shows how the DGND, AGND,
and bypass connections should be made to the DAC8562.
+5V
+5V
10-22µF
TANT.
20
VDD
0.1µF
CER.
10µF
DATA
DAC-8562
+5V
RETURN
+5V
POWER SUPPLY
CE
16
CLR
15
13
AGND 12
0.1µF
VOUT
TO OTHER
ANALOG CIRCUITS
DGND
10
Figure 28. Properly Filtering a +5 V Logic Supply
Can Yield a High Quality Analog Supply
TO POWER GROUND
Figure 29. Recommended Grounding and Bypassing
Scheme for the DAC-8562
REV. A
–9–
DAC8562
+12V OR +15V
0.1µF
Unipolar Output Operation
This is the basic mode of operation for the DAC8562. As shown
in Figure 30, the DAC8562 has been designed to drive loads as
low as 820 Ω in parallel with 500 pF. The code table for this operation is shown in Table III.
2
REF-02
6
0.1µF
4
+5V
10µF
1
0.1µF
DATA
DAC-8562
20
VDD
DATA
16
CLR
15
16
CLR
15
13
DGND
10
0V ≤ VOUT ≤ 4.095V
DAC-8562
CE
CE
VOUT
AGND
12
13
820 Ω
DGND
10
500pF
AGND
12
Figure 31. Operating the DAC8562 on +12 V or +15 V
Supplies Using a REF02 Voltage Reference
Measuring Offset Error
One of the most commonly specified endpoint errors associated
with real-world nonideal DACs is offset error.
Figure 30. Unipolar Output Operation
In most DAC testing, the offset error is measured by applying
the zero-scale code and measuring the output deviation from
0 volt. There are some DACs where offset errors may be present
but not observable at the zero scale because of other circuit limitations (for example, zero coinciding with single supply ground).
In these DACs, nonzero output at zero code cannot be read as
the offset error. In the DAC8562, for example, the zero-scale error is specified to be +3 LSBs. Since zero scale coincides with
zero volt, it is not possible to measure negative offset error.
Table III. Unipolar Code Table
Hexadecimal Number
in DAC Register
Decimal Number
in DAC Register
Analog Output
Voltage (V)
FFF
801
800
7FF
000
4095
2049
2048
2047
0
+4.095
+2.049
+2.048
+2.047
0
Operating the DAC8562 on +12 V or +15 V Supplies Only
Although the DAC8562 has been specified to operate on a
single, +5 V supply, a single +5 V supply may not be available in
many applications. Since the DAC8562 consumes no more than
6 mA, maximum, then an integrated voltage reference, such as
the REF02, can be used as the DAC8562 +5 V supply. The
configuration of the circuit is shown in Figure 31. Notice that
the reference’s output voltage requires no trimming because of
the REF02’s excellent load regulation and tight initial output
voltage tolerance. Although the maximum supply current of the
DAC8562 is 6 mA, local bypassing of the REF02’s output with
at least 0. 1 µF at the DAC’s voltage supply pin is recommended
to prevent the DAC’s internal digital circuits from affecting the
DAC’s internal voltage reference.
By adding a pull-down resistor from the output of the
DAC8562 to a negative supply as shown in Figure 32, offset errors can now be read at zero code. This configuration forces the
output P-channel MOSFET to source current to the negative
supply thereby allowing the designer to determine in which direction the offset error appears. The value of the resistor should
be such that, at zero code, current through the resistor is 200 µA
maximum.
+5V
0.1µF
20
VDD
DATA
DAC-8562
CE
VOUT
13
16
200µA MAX
CLR
15
DGND
10
AGND
12
V–
Figure 32. Measuring Zero-Scale or Offset Error
–10–
REV. A
DAC8562
+5V
0.1µF
20
+5V
P2
500 Ω
R1
10kΩ
VDD
DATA
VOUT 13
8
2
16
A1
R3
247k Ω
R2
12.7k
DAC-8562
CE
FULL SCALE
ADJUST
R4
23.7k Ω
10µF
3
1
–5V ≤ VO ≤ +5V
4
REFOUT 14
CLR
15
DGND
10
AGND
12
R6
10k Ω
–2.5V
–5V
P1
10k Ω
ZERO SCALE
ADJUST
R5
10k Ω
6
A2
A1, A2 = 1/2 OP-295
7
5
Figure 33. Bipolar Output Operation
 R4  
R2 
VO = 1 mV × Digital Code × 
 × 1 +

 R3 + R4  
R1 
Bipolar Output Operation
Although the DAC8562 has been designed for single supply operation, bipolar operation is achievable using the circuit illustrated in Figure 33. The circuit uses a single supply, rail-to-rail
OP295 op amp and the DAC’s internal +2.5 V reference to generate the –2.5 V reference required to level-shift the DAC output voltage. The circuit has been configured to provide an
output voltage in the range –5 V ≤ VOUT ≤ +5 V and is coded in
complementary offset binary. Although each DAC LSB corresponds to 1 mV, each output LSB has been scaled to 2.44 mV.
Table IV provides the relationship between the digital codes and
output voltage.
The transfer function of the circuit is given by:
 R4 
 R4 
VO = −1 mV × Digital Code × 
 + 2.5 × 

R1

 R2 

 R2 
– REFOUT × 

 R1 
For the ± 2 5 V output range and the circuit values shown in the
table, the transfer equation becomes:
VO = 1.22 mV × Digital Code – 2.5 V
Similarly, for the ± 5 V output range, the transfer equation becomes:
VO = 2.44 mV × Digital Code – 5 V
Note that, for ± 5 V output voltage operation, R5 is required as a
pull-down for REFOUT. Or, REFOUT can be buffered by an
op amp configured as a follower that can source and sink current.
and, for the circuit values shown, becomes:
VO = –2.44 mV × Digital Code + 5 V
Table IV. Bipolar Code Table
+5V
0.1µF
Hexadecimal Number
in DAC Register
Decimal Number
in DAC Register
Analog Output
Voltage (V)
FFF
801
800
7FF
000
4095
2049
2048
2047
0
–4 9976
–2.44E–3
0
+2.44E–3
+5
R2
20
VDD
For applications that do not require high accuracy, the circuit illustrated in Figure 34 can also be used to generate a bipolar
output voltage. In this circuit, only one op amp is used and no
potentiometers are used for offset and gain trim The output
voltage is coded in offset binary and is given by:
–11–
CE
16
CLR
15
+5V
R5
4.99k Ω
DAC-8562
To maintain monotonicity and accuracy, R1, R2, R4, R5, and
R6 should be selected to match within 0.01% and must all be of
the same (preferably metal foil) type to assure temperature coefficient matching. Mismatching between R1 and R2 causes offset
and gain errors while an R4 to R1 and R2 mismatch yields gain
errors.
REV. A
R1
REFOUT 14
DATA
8
2
A1
3
R3
1
VO
4
VOUT 13
DGND
10
AGND
R4
12
–5V
A1 = 1/2 OP-295
VOUT
RANGE
±2.5V
±5V
R1
10k
10k
R2
10k
20k
R3
10k
10k
R4
15.4k + 274
43.2k + 499
Figure 34. Bipolar Output Operation Without
Trim Version 1
DAC8562
Alternatively, the output voltage can be coded in complementary
offset binary using the circuit in Figure 35. This configuration
eliminates the need for a pull-down resistor or an op amp for
REFOUT The transfer equation of the circuit is given by:
 R2 
VO = –1 mV × Digital Code × 
 + REFOUT
 R1 
audio mixing consoles, music synthesizers, and other audio processors, VCAs, such as the SSM2018, adjust audio channel gain and
attenuation from front panel potentiometers. The VCA provides a
clean gain transition control of the audio level when the slew rate of
the analog input control voltage, VC, is properly chosen. The circuit in Figure 37 illustrates a volume control application using the
DAC8562 to control the attenuation of the SSM2018.
 R4  
R2 
×
 × 1 +

 R3 + R4  
R1 
+15V
10M Ω
P1
100kΩ
OFFSET
TRIM
and, for the values shown, becomes:
P2
500kΩ
SYMMETRY
TRIM
470k Ω
10pF
–15V
VO = −2.44 mV × Digital Code + 5 V
18kΩ
VOUT
R2
R1
+15V
VOUT
0.1µF
DAC-8562
VO
VIN
REFOUT
R1 = R3 = 10kΩ
R4
+15V
16
2
15
3
14
4
13
SSM-2018
5
18kΩ
R3
1
0.1µF
30k Ω
12
6
11
7
10
8
9
+15V
–15V
0.1µF
47pF
VO
RANGE
±5V
R2
23.7k + 715
2
R4
13.7k + 169 Ω
REF-02
Figure 35 Bipolar Output Operation Without
Trim Version 2
4
Generating a Negative Supply Voltage
Some applications may require bipolar output configuration, but
only have a single power supply rail available. This is very common in data acquisition systems using microprocessor-based systems. In these systems, only +12 V, +15 V, and/or +5 V are
available. Shown in Figure 36 is a method of generating a negative supply voltage using one CD4049, a CMOS hex inverter,
operating on +12 V or +15 V. The circuit is essentially a charge
pump where two of the six are used as an oscillator. For the values shown, the frequency of oscillation is approximately 3.5 kHz
and is fairly insensitive to supply voltage because R1 > 2 3 R2.
The remaining four inverters are wired in parallel for higher output current. The square-wave output is level translated by C2 to
a negative-going signal, rectified using a pair of 1N4001s, and
then filtered by C3. With the values shown, the charge pump
will provide an output voltage of –5 V for current loading in the
range 0.5 mA ≤ IOUT ≤ 10 mA with a +15 V supply and
0.5 mA ≤ IOUT ≤ 7 mA with a +12 V supply.
7
6
9
10
11
12
14
15
INVERTERS = CD4049
3
2
R1
510k Ω
5
4
C2
47µF
D2
1N4001
D1
1N4001
1N5231
5.1V
ZENER
C1
0.02µF
Figure 36. Generating a –5 V Supply When
Only +12 V or +15 V Are Available
Audio Volume Control
The DAC8562 is well suited to control digitally the gain or
attenuation of a voltage controlled amplifiers. In professional
20
CE
16
CLR
15
DATA
R6
825 Ω
DAC-8562
DGND
10
0V ≤ VC ≤ +2.24V
R7
1kΩ*
AGND
12
CCON
1µF
* – PRECISION RESISTOR PT146
1kΩ COMPENSATOR
Figure 37. Audio Volume Control
Since the supply voltage available in these systems is typically
± 15 V or ± 18 V, a REF02 is used to supply the +5 V required
to power the DAC. No trimming of the reference is required because of the reference’s tight initial tolerance and low supply
current consumption of the DAC8562. The SSM2018 is configured as a unity-gain buffer when its control voltage equals
0 volt. This corresponds to a 000H code from the DAC8562.
Since the SSM2018 exhibits a gain constant of –28 mV/dB
(typical), the DAC’s full-scale output voltage has to be scaled
down by R6 and R7 to provide 80 dB of attenuation when the
digital code equals FFFH. Therefore, every DAC LSB corresponds to 0.02 dB of attenuation. Table V illustrates the attenuation versus digital code of the volume control circuit.
R3
470 Ω
C3
47µF
0.1µF
13
Table V. SSM2018 VCA Attenuation vs.
DAC8562 Input Code
–5V
R2
5.1k Ω
+5V
6
Hexadecimal Number
in DAC Register
Control Voltage
(V)
VCA Attenuation
(dB)
000
400
800
C00
FFF
0
+0.56
+1.12
+1.68
+2.24
0
20
40
60
80
–12–
REV. A
DAC8562
To compensate for the SSM2018’s gain constant temperature
coefficient of –3300 ppm/°C, a 1 kΩ, temperature-sensitive
resistor (R7) manufactured by the Precision Resistor Company with a temperature coefficient of +3500 ppm/°C is used.
A CCON of 1 µF provides a control transition time of 1 ms which
yields a click-free change in the audio channel attenuation. Symmetry and offset trimming details of the VCA can be found in
the SSM2018 data sheet.
lower limits for the test are loaded into each DAC individually
by controlling HDAC/LDAC. If a signal at the test input is not
within the programmed limits, the output will indicate a logic
zero which will turn the red LED on.
R2
5kΩ
7
17
Information regarding the PT146 1 kΩ “Compensator” can be
obtained by contacting:
0.1µF
6
18
Precision Resistor Company, Incorporated
10601 75th Street North
Largo, FL 34647
(813) 541-5771
RCS
100Ω
12
R1
100k
AMP-05
10
0mA ≤ IOUT ≤ 10mA
2.4µA/ LSB
8
9
1
11
5
2
A High-Compliance, Digitally Controlled Precision Current
Source
4
The circuit in Figure 38 shows the DAC8562 controlling a
high-compliance, precision current source using an AMP05 instrumentation amplifier. The AMP05’s reference pin becomes
the input, and the “old” inputs now monitor the voltage across a
precision current sense resistor, RCS. Voltage gain is set to unity,
so the transfer function is given by the following equation:
IOUT =
+15V
P1
100kΩ
0.1µF
–15V
+15V
VIN
RCS
0.1µF
2
REF-02
If RCS equals 100 Ω, the output current is limited to +10 mA
with a 1 V input. Therefore, each DAC LSB corresponds to
2.4 µA. If a bipolar output current is required, then the circuit
in Figure 33 can be modified to drive the AMP05’s reference
pin with a ± 1 V input signal.
0.1µF
6
4
20
CE
16
CLR
15
R3
3k
DAC-8562
13
Potentiometer P1 trims the output current to zero with the input at 0 V. Fine gain adjustment can be accomplished by adjusting R1 or R2.
DATA
DGND
AGND
10
12
R4
1k
A Digitally Programmable Window Detector
A digitally programmable, upper/lower limit detector using two
DAC8562s is shown in Figure 39. The required upper and
+5V
+5V
1k Ω
0.1µF
Figure 38. A High-Compliance, Digitally Controlled
Precision Current Source
VIN
+5V
20
+5V
16
15
R1
604Ω
R2
604Ω
RED LED
T1
GREEN LED
T1
0.1µF
DAC-8562
13
3
DGND AGND
12
10
2
+5V
5
1/6
74HC05
C1
2
C2
1
PASS/FAIL
4
1
+5V
0.1µF
7
6
20
HDAC/LDAC
16
CLR
15
DATA
12
DAC-8562
3
4
1/6
74HC05
13
DGND AGND
10
C1, C2 = 1/4 CMP-404
12
Figure 39. A Digitally Programmable Window Detector
REV. A
–13–
DAC8562
Decoding Multiple DAC8562s
when PC1 is cleared. The DAC’s CLR input, controlled by the
M68HC11’s PC2 output line, provides an asynchronous clear
function that sets the DAC’s output to zero. Included in this section is the source code for operating the DAC-8562–M68HC11
interface.
The CE function of the DAC8562 can be used in applications
to decode a number of DACs. In this application, all DACs receive the same input data; however, only one of the DACs’ CE
input is asserted to transfer its parallel input register contents
into the DAC. In this circuit, shown in Figure 40, the CE timing is generated by a 74HC139 decoder and should follow the
DAC8562’s standard timing requirements. To prevent timing
errors, the 74HC139 should not be activated by its ENABLE
input while the coded address inputs are changing. A simple
timing circuit, R1 and C1, connected to the DACs’ CLR pins
resets all DAC outputs to zero during power-up.
+5V
C1
0.1µF
R1
1k Ω
VOUT1
15
13
16
MICROPROCESSOR INTERFACING
DAC-8562–MC68HC11 INTERFACE
DATA
The circuit illustrated in Figure 41 shows a parallel interface between the DAC8562 and a popular 8-bit microcontroller, the
M68HC11, which is configured in a single-chip operating
mode. The interface circuit consists of a pair of 74ACT11373
transparent latches and an inverter. The data is loaded into the
latches in two 8-bit bytes; the first byte contains the four most
significant bits, and the lower 8 bits are in the second byte. Data
is taken from the microcontroller’s port B output lines, and
three interface control lines, CLR, CE, and MSB/LSB, are controlled by the M68HC11's PC2, PC1, and PC0 output lines, respectively. To transfer data into the DAC, PC0 is set, enabling
U1’s outputs. The first data byte is loaded into U1 where the
four least significant bits of the byte are connected to
MSB–DB8. PC0 is then cleared; this latches U1’s inputs and
enables U2’s outputs. U2s outputs now become DB7–DB0.
The DAC output is updated with the contents of U1 and U2
DAC-8562
#1
+5V
VOUT2
15
13
74HC139
0.1µF
ENABLE
16
1
2
CODED
ADDRESS
3
15
+5V
1Y0
VCC
1G
1Y1
1A
1Y2
1B
1Y3
2G
2Y0
1k Ω 14
2Y1
2A
13
8
2B
2Y2
GND
2Y3
16
4
5
DAC-8562
#2
6
12
11
10
9
VOUT3
15
7
13
16
NC
DAC-8562
#3
NC
NC
VOUT4
15
13
NC
16
DAC-8562
#4
Figure 40. Decoding Multiple DAC8562s Using the CE Pin
74ACT11373
*M6BHC11
PC2
13
23
CLR
22
PC1
PC0
CE
74HC04
MSB/ LSB 1
2
21
20
1
16
C
1D
1Q
2D
2Q
3D
3Q
4D
4Q
5D
U1
NC
2
3
4
9
10
6D
6Q
7D
7Q
8D
8Q
15
14
5Q
1
24
PB6
PB5
PB4
PB3
PB2
PB1
PB0
22
21
20
1
16
15
14
24
*DAC-8562
NC
PC2
15
16
PC1
9
12
8
7
OC
6
74ACT11373
5
CLR
CE
MSB
DB10
DB9
DB8
DB7
4
C
23
NC
11
13
PB7
NC
1D
1Q
2D
2Q
3D
3Q
4D
5D
4Q
U2
5Q
6D
6Q
7D
7Q
8D
8Q
1
3
2
2
3
1
4
19
9
18
10
17
DB6
U3
VOUT
13
DB5
DB4
DB3
DB2
DB1
LSB
11
12
OC
*ADDITIONAL PINS OMITTED FOR CLARITY
Figure 41. DAC8562 to MC68HC11 Interface
–14–
REV. A
DAC8562
DAC8562 – M68HC11 Interface Program Source Code
DAC8562–M68HC11 Interface Program Source Code (Continued)
*
* DAC8562 to M68HC11 Interface Assembly Program
* Adolfo A. Garcia
* September 14, 1992
*
* M68HC11 Register definitions
*
PORTB
EQU
$1004
PORTC
EQU
$1003
Port C control register
*
“0,0,0,0;0,CLR/,CE/,MSB-LSB/”
DDRC
EQU
$1007
Port C data direction
*
* RAM variables:
MSBS are encoded from 0 (Hex) to F (Hex)
*
LSBS are encoded from 00 (Hex) to F (Hex)
*
DAC requires two 8-bit loads
*
MSBS
EQU
$00
Hi-byte: “0,0,0,0;MSB,DB10,DB9,DB8”
LSBS
EQU
$01
Lo-byte: “DB7,DB6,DB5,DB4;DB3,DB2,
DB1,DB0”
*
* Main Program
*
ORG
$C000
Start of user’s RAM in EVB
INIT
LDS
#$CFFF
Top of C page RAM
*
* Initialize Port C Outputs
*
LDAA #$07
0,0,0,0;0,1,1,1
STAA DDRC
CLR/,CE/, and MSB-LSB/ are now enabled
as outputs
LDAA #$06
0,0.0,0;0,1,1,0
*
CLR/-Hi, CE/-Hi, MSB-LSB/-Lo
STAA PORTC
Initialize Port C Outputs
*
* Call update subroutine
*
BSR
UPDATE
Xfer 2 8-bit words to DAC8562
JMP
$E000
Restart BUFFALO
*
* Subroutine UPDATE
*
UPDATE PSHX
Save registers X, Y, and A
PSHY
PSHA
*
* Enter contents of the Hi-byte input register
*
LDAA #$0A
0,0,0,0;1,0,1,0
STAA MSBS
MSBS are set to 0A (Hex)
*
* Enter Contents of’ Lo-byte input register
*
LDAA #$AA
1,0,1,0;1,0,1,0
STAA LSBS
LSBS are set to AA (Hex)
*
LDX
#MSBS
Stack pointer at 1st byte to send via Port B
LDY
#$1000
Stack pointer at on-chip registers
*
* Clear DAC output to zero
*
BCLR PORTC,Y $04 Assert CLR/
BSET PORTC,Y $04 De-assert CLR/
*
* Loading input buffer latches
*
BSET PORTC,Y $01 Set hi-byte register load
TFRLP
LDAA 0,X
Get a byte to transfer via Port B
STAA PORTB
Write data to input register
INX
Increment counter to next byte for transfer
CPX
#LSBS+1
Are we done yet ?
BEQ
DUMP
If yes, update DAC output
BCLR PORTC,Y $01 Latch hi-byte register and set lo-byte register
load
BRA
TFRLP
*
* Update DAC output with contents of input registers
*
DUMP
BCLR PORTC,Y $02 Assert CE/
BSET PORTC,Y $02 Latch DAC register
*
PULA
When done, restore registers X, Y & A
PULY
PULX
RTS
** Return to Main Program **
REV. A
–15–
DAC8562
OUTLINE DIMENSIONS
Dimensions shown in inches and (mm).
20
20-Pin Cerdip (R-Suffix)
20
11
0.255 (6.477)
0.245 (6.223)
PIN 1
0.28 (7.11)
0.24 (6.1)
10
1
1.07 (27.18) MAX
0.065 (1.66)
0.045 (1.15)
0.18 (4.57)
0.125 (3.18)
0.20 (5.0)
0.14 (3.56)
0.125
(3.175)
MIN
0.11 (2.79)
0.09 (2.28)
0.32 (8.128)
0.29 (7.366)
0.97 (24.64)
0.935 (23.75)
0.135 (3.429)
0.125 (3.17)
0.021 (0.533)
0.015 (0.381)
10
1
0.32 (8.128)
0.30 (7.62)
0.145
(3.683)
MIN
11
PIN 1
15°
0
SEATING
PLANE
0.011 (0.28)
0.009 (0.23)
0.15 (3.8)
0.125 (3.18)
0.011 (0.28)
0.009 (0.23)
C1713–24–10/92
20-Pin Plastic DIP (P-Suffix)
15°
0.02 (0.5)
0.016 (0.14)
LEAD NO. 1 IDENTIFIED BY DOT OR NOTCH
LEADS ARE SOLDER OR TIN-PLATED KOVAR OR ALLOY 42.
0.11 (2.79)
0.09 (2.28)
0.07 (1.78)
0.05 (1.27)
SEATING
PLANE
0°
LEAD NO. 1 IDENTIFIED BY DOT OR NOTCH
LEADS ARE SOLDER OR TIN-PLATED KOVAR OR ALLOY 42.
20-Lead SOIC (S-Suffix)
11
20
0.299 (7.60)
0.291 (7.40)
0.419 (10.65)
0.404 (10.00)
PIN 1
1
10
0.512 (13.00)
0.496 (12.60)
0.107 (2.72)
0.089 (2.26)
0.050 (1.27)
BSC
0.022 (0.56)
0.014 (0.36)
0.015 (0.38)
0.007 (0.18)
0.034 (0.86)
0.018 (0.46)
PRINTED IN U.S.A.
0.011 (0.275)
0.005 (0.125)
–16–
REV. A