Page 1
TL/H/5687
DAC0808/DAC0807/DAC0806 8-Bit D/A Converters
January 1995
DAC0808/DAC0807/DAC0806 8-Bit D/A Converters
General Description
The DAC0808 series is an 8-bit monolithic digital-to-analog
converter (DAC) featuring a full scale output current settling
time of 150 ns while dissipating only 33 mW with
g
5V sup-
plies. No reference current (I
REF
) trimming is required for
most applications since the full scale output current is typically
g
1 LSB of 255 I
REF
/ 256. Relative accuracies of bet-
ter than
g
0.19% assure 8-bit monotonicity and linearity
while zero level output current of less than 4 mA provides
8-bit zero accuracy for I
REF
t
2 mA. The power supply currents of the DAC0808 series are independent of bit codes,
and exhibits essentially constant device characteristics over
the entire supply voltage range.
The DAC0808 will interface directly with popular TTL, DTL
or CMOS logic levels, and is a direct replacement for the
MC1508/MC1408. For higher speed applications, see
DAC0800 data sheet.
Features
Y
Relative accuracy:g0.19% error maximum (DAC0808)
Y
Full scale current match:g1 LSB typ
Y
7 and 6-bit accuracy available (DAC0807, DAC0806)
Y
Fast settling time: 150 ns typ
Y
Noninverting digital inputs are TTL and CMOS compatible
Y
High speed multiplying input slew rate: 8 mA/ms
Y
Power supply voltage range:g4.5V tog18V
Y
Low power consumption: 33 mW
@
g
5V
Block and Connection Diagrams
TL/H/5687– 1
Dual-In-Line Package
TL/H/5687– 2
Small-Outline Package
TL/H/5687– 13
Top View
Ordering Information
ACCURACY
OPERATING TEMPERATURE ORDER NUMBERS
RANGE J PACKAGE (J16A)* N PACKAGE (N16A)* SO PACKAGE (M16A)
DAC0808LCN MC1408P8 DAC0808LCM
7-bit 0
§
CsT
A
s
a
75§C DAC0807LCJ MC1408L7 DAC0807LCN MC1408P7 DAC0807LCM
6-bit 0
§
CsT
A
s
a
75§C DAC0806LCJ MC1408L6 DAC0806LCN MC1408P6 DAC0806LCM
*Note. Devices may be ordered by using either order number.
Order Number
DAC0808, DAC0807,
or DAC0806
See NS Package
Number J16A,
M16A or N16A
C
1995 National Semiconductor Corporation RRD-B30M115/Printed in U. S. A.
Page 2
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales
Office/Distributors for availability and specifications.
Power Supply Voltage
V
CC
a
18 V
DC
V
EE
b
18 V
DC
Digital Input Voltage, V5–V12
b
10 VDCtoa18 V
DC
Applied Output Voltage, V
O
b
11 VDCtoa18 V
DC
Reference Current, I
14
5mA
Reference Amplifier Inputs, V14, V15 V
CC,VEE
Power Dissipation (Note 3) 1000 mW
ESD Susceptibility (Note 4) TBD
Storage Temperature Range
b
65§Ctoa150§C
Lead Temp. (Soldering, 10 seconds)
Dual-In-Line Package (Plastic) 260
§
C
Dual-In-Line Package (Ceramic) 300
§
C
Surface Mount Package
Vapor Phase (60 seconds) 215
§
C
Infrared (15 seconds) 220
§
C
Operating Ratings
Temperature Range T
MIN
s
T
A
s
T
MAX
DAC0808LC Series 0sT
A
s
a
75§C
Electrical Characteristics
(V
CC
e
5V, V
EE
eb
15 VDC,V
REF
/R14e2 mA, DAC0808: T
A
eb
55§Ctoa125§C, DAC0808C, DAC0807C, DAC0806C, T
A
e
0§Ctoa75§C, and all digital inputs at high logic level unless otherwise noted.)
Symbol Parameter Conditions Min Typ Max Units
E
r
Relative Accuracy (Error Relative
(Figure 4)
%
to Full Scale I
O
)
DAC0808LC (LM1408-8)
g
0.19 %
DAC0807LC (LM1408-7), (Note 5)
g
0.39 %
DAC0806LC (LM1408-6), (Note 5)
g
0.78 %
Settling Time to Within (/2 LSB T
A
e
25§C (Note 6), 150 ns
(Includes t
PLH
)
(Figure 5)
t
PLH,tPHL
Propagation Delay Time T
A
e
25§C,
(Figure 5)
30 100 ns
TCI
O
Output Full Scale Current Drift
g
20 ppm/§C
MSB Digital Input Logic Levels
(Figure 3)
V
IH
High Level, Logic ‘‘1’’ 2 V
DC
V
IL
Low Level, Logic ‘‘0’’ 0.8 V
DC
MSB Digital Input Current
(Figure 3)
High Level V
IH
e
5V 0 0.040 mA
Low Level V
IL
e
0.8V
b
0.003
b
0.8 mA
I
15
Reference Input Bias Current
(Figure 3)
b
1
b
3 mA
Output Current Range
(Figure 3)
V
EE
eb
5V 0 2.0 2.1 mA
V
EE
eb
15V, T
A
e
25§C 0 2.0 4.2 mA
I
O
Output Current V
REF
e
2.000V,
R14e1000X,
(Figure 3)
1.9 1.99 2.1 mA
Output Current, All Bits Low
(Figure 3)
04mA
Output Voltage Compliance (Note 2) E
r
s
0.19%, T
A
e
25§C
V
EE
eb
5V, I
REF
e
1mA
b
0.55,a0.4 V
DC
VEEBelowb10V
b
5.0,a0.4 V
DC
2
Page 3
Electrical Characteristics (Continued)
(V
CC
e
5V, V
EE
eb
15 VDC,V
REF
/R14e2 mA, DAC0808: T
A
eb
55§Ctoa125§C, DAC0808C, DAC0807C, DAC0806C, T
A
e
0§Ctoa75§C, and all digital inputs at high logic level unless otherwise noted.)
Symbol Parameter Conditions Min Typ Max Units
SRI
REF
Reference Current Slew Rate
(Figure 6)
4 8 mA/ms
Output Current Power Supply
b
5VsV
EE
s
b
16.5V 0.05 2.7 mA/V
Sensitivity
Power Supply Current (All Bits
(Figure 3)
Low)
I
CC
2.3 22 mA
I
EE
b
4.3
b
13 mA
Power Supply Voltage Range T
A
e
25§C,
(Figure 3)
V
CC
4.5 5.0 5.5 V
DC
V
EE
b
4.5
b
15
b
16.5 V
DC
Power Dissipation
All Bits Low V
CC
e
5V, V
EE
eb
5V 33 170 mW
V
CC
e
5V, V
EE
eb
15V 106 305 mW
All Bits High V
CC
e
15V, V
EE
eb
5V 90 mW
V
CC
e
15V, V
EE
eb
15V 160 mW
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications do not apply when operating
the device beyond its specified operating conditions.
Note 2: Range control is not required.
Note 3: The maximum power dissipation must be derated at elevated temperatures and is dictated by T
JMAX
, iJA, and the ambient temperature, TA. The maximum
allowable power dissipation at any temperature is P
D
e
(T
JMAX
b
TA)/iJAor the number given in the Absolute Maixmum Ratings, whichever is lower. For this
device, T
JMAX
e
125§C, and the typical junction-to-ambient thermal resistance of the dual-in-line J package when the board mounted is 100§C/W. For the dual-in-
line N package, this number increases to 175
§
C/W and for the small outline M package this number is 100§C/W.
Note 4: Human body model, 100 pF discharged through a 1.5 kX resistor.
Note 5: All current switches are tested to guarantee at least 50% of rated current.
Note 6: All bits switched.
Note 7: Pin-out numbers for the DAL080X represent the dual-in-line package. The small outline package pinout differs from the dual-in-line package.
Typical Application
V
O
e
10V
#
A1
2
a
A2
4
a
...
A8
256
J
TL/H/5687– 3
FIGURE 1.a10V Output Digital to Analog Converter (Note 7)
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Typical Performance Characteristics
V
CC
e
5V, V
EE
eb
15V, T
A
e
25§C, unless otherwise noted
Logic Input Current vs
Input Voltage Bit Transfer Characteristics
Logic Threshold Voltage vs
Temperature
Output Current vs Output
Voltage (Output Voltage
Compliance)
Output Voltage Compliance
vs Temperature
Typical Power Supply
Current vs Temperature
Typical Power Supply
Current vs V
EE
Typical Power Supply
Current vs V
CC
Reference Input
Frequency Response
Unless otherwise specified: R14
e
R15e1kX,Ce15 pF, pin 16 to
V
EE;RL
e
50X, pin 4 to ground.
Curve A: Large Signal Bandwidth
Method of
Figure 7
,V
REF
e
2 Vp-p
offset 1 V above ground.
Curve B: Small Signal Bandwidth
Method of
Figure 7
,R
L
e
250X,V
REF
e
50 mVp-p offset 200 mV above
ground.
Curve C: Large and Small Signal
Bandwidth Method of
Figure 9
(no op
amp, R
L
e
50X), R
S
e
50X,V
REF
e
2V, V
S
e
100 mVp-p centered at 0V.
TL/H/5687– 5
4
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TL/H/5687– 4
FIGURE 2. Equivalent Circuit of the DAC0808 Series (Note 7)
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Test Circuits
TL/H/5687– 6
VIand I1apply to inputs A1 – A8.
The resistor tied to pin 15 is to temperature compensate the
bias current and may not be necessary for all applications.
I
O
e
K
#
A1
2
a
A2
4
a
A3
8
a
A4
16
a
A5
32
a
A6
64
a
A7
128
a
A8
256
J
where K
j
V
REF
R14
and A
N
e
‘‘1’’ if ANis at high level
A
N
e
‘‘0’’ if ANis at low level
FIGURE 3. Notation Definitions Test Circuit (Note 7)
TL/H/5687– 7
FIGURE 4. Relative Accuracy Test Circuit (Note 7)
TL/H/5687– 8
FIGURE 5. Transient Response and Settling Time (Note 7)
6
Page 7
Test Circuits (Continued)
TL/H/5687– 9
FIGURE 6. Reference Current Slew Rate Measurement (Note 7)
TL/H/5687– 10
FIGURE 7. Positive V
REF
(Note 7)
TL/H/5687– 11
FIGURE 8. Negative V
REF
(Note 7)
Application Hints
REFERENCE AMPLIFIER DRIVE AND COMPENSATION
The reference amplifier provides a voltage at pin 14 for converting the reference voltage to a current, and a turn-around
circuit or current mirror for feeding the ladder. The reference
amplifier input currrent, I
14
, must always flow into pin 14,
regardless of the set-up method or reference voltage polarity.
Connections for a positive voltage are shown in
Figure 7
.
The reference voltage source supplies the full current I
14
.
For bipolar reference signals, as in the multiplying mode,
TL/H/5687– 12
FIGURE 9. Programmable Gain Amplifier or
Digital Attenuator Circuit (Note 7)
R15 can be tied to a negative voltage corresponding to the
minimum input level. It is possible to eliminate R15 with only
a small sacrifice in accuracy and temperature drift.
The compensation capacitor value must be increased with
increases in R14 to maintain proper phase margin; for R14
values of 1, 2.5 and 5 kX, minimum capacitor values are 15,
37 and 75 pF. The capacitor may be tied to either V
EE
or
ground, but using V
EE
increases negative supply rejection.
7
Page 8
Application Hints (Continued)
A negative reference voltage may be used if R14 is grounded and the reference voltage is applied to R15 as shown in
Figure 8
. A high input impedance is the main advantage of
this method. Compensation involves a capacitor to V
EE
on
pin 16, using the values of the previous paragraph. The negative reference voltage must be at least 4V above the V
EE
supply. Bipolar input signals may be handled by connecting
R14 to a positive reference voltage equal to the peak positive input level at pin 15.
When a DC reference voltage is used, capacitive bypass to
ground is recommended. The 5V logic supply is not recommended as a reference voltage. If a well regulated 5V supply which drives logic is to be used as the reference, R14
should be decoupled by connecting it to 5V through another
resistor and bypassing the junction of the 2 resistors with
0.1 mF to ground. For reference voltages greater than 5V, a
clamp diode is recommended between pin 14 and ground.
If pin 14 is driven by a high impedance such as a transistor
current source, none of the above compensation methods
apply and the amplifier must be heavily compensated, decreasing the overall bandwidth.
OUTPUT VOLTAGE RANGE
The voltage on pin 4 is restricted to a range of
b
0.55 to
0.4V when V
EE
eb
5V due to the current switching meth-
ods employed in the DAC0808.
The negative output voltage compliance of the DAC0808 is
extended to
b
5V where the negative supply voltage is more
negative than
b
10V. Using a full-scale current of 1.992 mA
and load resistor of 2.5 kX between pin 4 and ground will
yield a voltage output of 256 levels between 0 and
b
4.980V. Floating pin 1 does not affect the converter
speed or power dissipation. However, the value of the load
resistor determines the switching time due to increased voltage swing. Values of R
L
up to 500X do not significantly
affect performance, but a 2.5 kX load increases worst-case
settling time to 1.2 ms (when all bits are switched ON). Refer
to the subsequent text section on Settling Time for more
details on output loading.
OUTPUT CURRENT RANGE
The output current maximum rating of 4.2 mA may be used
only for negative supply voltages more negative than
b
8V,
due to the increased voltage drop across the resistors in the
reference current amplifier.
ACCURACY
Absolute accuracy is the measure of each output current
level with respect to its intended value, and is dependent
upon relative accuracy and full-scale current drift. Relative
accuracy is the measure of each output current level as a
fraction of the full-scale current. The relative accuracy of the
DAC0808 is essentially constant with temperature due to
the excellent temperature tracking of the monolithic resistor
ladder. The reference current may drift with temperature,
causing a change in the absolute accuracy of output current. However, the DAC0808 has a very low full-scale current drift with temperature.
The DAC0808 series is guaranteed accurate to within
g
(/2
LSB at a full-scale output current of 1.992 mA. This corresponds to a reference amplifier output current drive to the
ladder network of 2 mA, with the loss of 1 LSB (8 mA) which
is the ladder remainder shunted to ground. The input current
to pin 14 has a guaranteed value of between 1.9 and 2.1
mA, allowing some mismatch in the NPN current source
pair. The accuracy test circuit is shown in
Figure 4
. The 12-
bit converter is calibrated for a full-scale output current of
1.992 mA. This is an optional step since the DAC0808 accuracy is essentially the same between 1.5 and 2.5 mA. Then
the DAC0808 circuits’ full-scale current is trimmed to the
same value with R14 so that a zero value appears at the
error amplifier output. The counter is activated and the error
band may be displayed on an oscilloscope, detected by
comparators, or stored in a peak detector.
Two 8-bit D-to-A converters may not be used to construct a
16-bit accuracy D-to-A converter. 16-bit accuracy implies a
total error of
g
(/2 of one part in 65,536 org0.00076%,
which is much more accurate than the
g
0.019% specifica-
tion provided by the DAC0808.
MULTIPLYING ACCURACY
The DAC0808 may be used in the multiplying mode with
8-bit accuracy when the reference current is varied over a
range of 256:1. If the reference current in the multiplying
mode ranges from 16 mA to 4 mA, the additional error contributions are less than 1.6 mA. This is well within 8-bit accuracy when referred to full-scale.
A monotonic converter is one which supplies an increase in
current for each increment in the binary word. Typically, the
DAC0808 is monotonic for all values of reference current
above 0.5 mA. The recommended range for operation with
a DC reference current is 0.5 to 4 mA.
SETTLING TIME
The worst-case switching condition occurs when all bits are
switched ON, which corresponds to a low-to-high transition
for all bits. This time is typically 150 ns for settling to within
g
(/2 LSB, for 8-bit accuracy, and 100 ns to (/2 LSB for 7 and
6-bit accuracy. The turn OFF is typically under 100 ns.
These times apply when R
L
s
500X and C
O
s
25 pF.
Extra care must be taken in board layout since this is usually
the dominant factor in satisfactory test results when measuring settling time. Short leads, 100 mF supply bypassing
for low frequencies, and minimum scope lead length are all
mandatory.
8
Page 9
Physical Dimensions inches (millimeters)
Dual-In-Line Package
Order Number DAC0807 or DAC0806
NS Package Number J16A
Small Outline Package
Order Number DAC0806LCM, DAC0807LCM or DAC0808LCM
NS Package Number M16A
9
Page 10
DAC0808/DAC0807/DAC0806 8-Bit D/A Converters
Physical Dimensions inches (millimeters) (Continued)
Dual-In-Line Package
Order Number DAC0808, DAC0807 or DAC0806
NS Package Number N16A
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SEMICONDUCTOR CORPORATION. As used herein:
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into the body, or (b) support or sustain life, and whose be reasonably expected to cause the failure of the life
failure to perform, when properly used in accordance support device or system, or to affect its safety or
with instructions for use provided in the labeling, can effectiveness.
be reasonably expected to result in a significant injury
to the user.
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Corporation Europe Hong Kong Ltd. Japan Ltd.
1111 West Bardin Road Fax: (
a
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a
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a
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