MC1408-8
8-bit multiplying D/A converter
Product data
Supersedes data of 1994 Aug 31
File under Integrated Circuits, IC11 Handbook
2001 Aug 03
INTEGRATED CIRCUITS
Philips Semiconductors Product data
MC1408-88-bit multiplying D/A converter
2
2001 Aug 03 853-0935 26835
DESCRIPTION
The MC1408-8 is an 8-bit monolithic digital-to-analog converter
which provides high-speed performance with low cost. It is designed
for use where the output current is a linear product of an 8-bit digital
word and an analog reference voltage.
FEATURES
•Fast settling time: 70 ns (typ)
•Relative accuracy ±0.19% (max error)
•Non-inverting digital inputs are TTL and CMOS compatible
•High-speed multiplying rate 4.0 mA/µs (input slew)
•Output voltage swing +0.5 V to –5.0 V
•Standard supply voltages +5.0 V and –5.0 V to –15 V
APPLICATIONS
•T racking A-to-D converters
•2 1/2-digit panel meters and DVMs
•W aveform synthesis
•Sample-and-Hold
•Peak detector
•Programmable gain and attenuation
•CRT character generation
•Audio digitizing and decoding
•Programmable power supplies
•Analog-digital multiplication
•Digital-digital multiplication
•Analog-digital division
•Digital addition and subtraction
•Speech compression and expansion
•Stepping motor drive modems
•Servo motor and pen drivers
PIN CONFIGURATIONS
N Package
D Package1
NC
GND
VEE
COMPEN
TOP VIEW
1
2
3
4
5
6
7
89
10
11
12
13
14
16
15
1
2
3
4
5
6
7
89
10
11
12
13
14
16
15
VREF(–)
IO
MSB A1
A2
A3
A4
VREF(+)
VCC
A8 LSB
A7
A6
A5
A1 MSB
A2
A3
A4
A8 LSB
A7
A6
A5
VREF(–)
VREF(+)
COMPEN
NC
GND
V–
IO
V+
NOTE:
1. SO and non-standard pinouts.
SL00048
Figure 1. Pin Configurations
ORDERING INFORMATION
DESCRIPTION TEMPERATURE RANGE ORDER CODE DWG #
16-Pin Plastic Dual In-Line Package (DIP) 0 °C to +70 °C MC1408-8N SOT38-4
16-Pin Small Outline (SO) Package 0 °C to +70 °C MC1408-8D SOT109-1
Philips Semiconductors Product data
MC1408-88-bit multiplying D/A converter
2001 Aug 03 3
BLOCK DIAGRAM
CURRENT SWITCHES
56789101112
MSB LSB
REFERENCE
CURRENT
AMPLIFIER
14
2
13
16
GND
COMPEN
NPN CURRENT SOURCE PAIR
A1A2A3A4A5A6A7A8
4
BIAS
CURRENT
R-2R LADDER
15
(+)
(–)
VREF
VREF
VCC
3
VEE
IO
SL00049
Figure 2. Block Diagram
CIRCUIT DESCRIPTION
The MC1408-8 consists of a reference current amplifier, an R-2R
ladder, and 8 high-speed current switches. For many applications,
only a reference resistor and reference voltage need be added.
The switches are non-inverting in operation; therefore, a high state
on the input turns on the specified output current component.
The switch uses current steering for high speed, and a termination
amplifier consisting of an active load gain stage with unity gain
feedback. The termination amplifier holds the parasitic capacitance
of the ladder at a constant voltage during switching, and provides a
low impedance termination of equal voltage for all legs of the ladder.
The R-2R ladder divides the reference amplifier current into
binary-related components, which are fed to the remainder current
which is equal to the least significant bit. This current is shunted to
ground, and the maximum output current is 255/256 of the reference
amplifier current, or 1.992 mA for a 2.0 mA reference amplifier
current if the NPN current source pair is perfectly matched.
ABSOLUTE MAXIMUM RATINGS
SYMBOL PARAMETER RATING UNIT
VCC Positive power supply voltage +5.5 V
VEE Negative power supply voltage –16.5 V
V5 – V12 Digital input voltage 0 to VCC V
VOApplied output voltage –5.2 to +18 V
I14 Reference current 5.0 mA
V14, V15 Reference amplifier inputs VEE to VCC
Maximum power dissipation, Tamb = 25 °C (still-air)1
PDN package 1450 mW
D package 1080 mW
Tamb Operating temperature range 0 to +75 °C
Tstg Storage temperature range –65 to +150 °C
Tsld Lead soldering temperature (10 sec) +230 °C
NOTES:
1. Derate above 25°C, at the following rates:
N package at 11.6 mW/°C;
D package at 8.6 mW/°C
Philips Semiconductors Product data
MC1408-88-bit multiplying D/A converter
2001 Aug 03 4
DC ELECTRICAL CHARACTERISTICS
Pin 3 must be 3 V more negative than the potential to which R15 is returned. VCC = +5.0 VDC, VEE = –15 VDC, VREF/R14 = 2.0 mA unless
otherwise specified. Tamb = 0 °C to 75 °C, unless otherwise noted.
SYMBOL
PARAMETER
TEST CONDITIONS
MC1408-8
UNIT
SYMBOL
PARAMETER
TEST
CONDITIONS
Min Typ Max
UNIT
ErRelative accuracy Error relative to full-scale IO, Figure 6 ±0.19 %
tSSettling time1To within 1/2 LSB, includes tPLH;
Tamb = +25 °C, Figure 7 70 ns
Propagation delay time
tPLH Low-to-High Tamb = +25 °C, Figure 7 35 100 ns
tPHL High-to-Low
TCIOOutput full-scale current drift –20 ppm/°C
Digital input logic level (MSB)
VIH High Figure 8 2.0 VDC
VIL Low 0.8
Digital input current (MSB) Figure 8
IIH High VIH = 5.0 V 0 0.04 mA
IIL Low VIL = 0.8 V –0.4 –0.8
I15 Reference input bias current Pin 15, Figure 8 –1.0 –5.0 µA
Figure 8
IOR Output current range VEE = –5.0 V 0 2.0 2.1 mA
VEE = –7.0 V to –15 V 0 2.0 4.2
IOOutput current Figure 8
VREF = 2.000 V, 1.9 1.99 2.1 mA
R14 = 1000 Ω
IO(min) Off-state All bits low 0 4.0 µA
Er ≤ 0.19% at
TA = +25°C, Figure 8
VO
Out
p
ut voltage com
p
liance
VEE = –5V –0.6 –0.55,
VDC
V
O
Out ut
voltage
com liance
+10 +0.5
V
DC
VEE below –10V –5.5, –5.0,
+10 +0.5
SRIREF Reference current slew rate Figure 9 8.0 mA/µs
PSRR(–) Output current power supply
sensitivity IREF = 1 mA 0.5 2.7 µA/V
Power supply current
ICC Positive All bits low, Figure 8 +2.5 +22 mA
IEE Negative –6.5 –13
Power supply voltage range
VCCR Positive Tamb = +25 °C, Figure 8 +4.5 +5.0 +5.5 VDC
VEER Negative –4.5 –15 –16.5
All bits low, Figure 8
PDPower dissipation VEE = –5.0 VDC 34 170 mW
VEE = –15.0 VDC 110 305
NOTES:
1. All bits switched.
Philips Semiconductors Product data
MC1408-88-bit multiplying D/A converter
2001 Aug 03 5
TYPICAL PERFORMANCE CHARACTERISTICS
D-to-A TRANSFER CHARACTERISTICS
I OUTPUT CURRENT (mA)
O
0
1.0
2.0
(00000000) INPUT DIGITAL WORD (11111111)
SL00050
Figure 3. Typical Performance Characteristics
FUNCTIONAL DESCRIPTION
Reference Amplifier Drive and Compensation
The reference amplifier input current must always flow into Pin 14.
regardless of the setup method or reference supply voltage polarity.
Connections for a positive reference voltage are shown in Figure 4.
The reference voltage source supplies the full reference current. For
bipolar reference signals, as in the multiplying mode, R15 can be
tied to a negative voltage corresponding to the minimum input level.
R15 may be eliminated and Pin 15 grounded, with only a small
sacrifice in accuracy and temperature drift.
A1
A2
A3
A4
A5
A6
A7
A8
5
6
7
8
9
10
11
12
3
MC1408
13
14
15
1
2
4
16
SEE TEXT FOR VALUES OF C.
C
R14 = R15
(+)VREF
R14
R15
RL
IO
VEE
VCC
SL00051
Figure 4. Positive VREF
The compensation capacitor value must be increased with
increasing values of R14 to maintain proper phase margin. For R14
values of 1.0, 2.5, and 5.0 kΩ, minimum capacitor values are 15, 37,
and 75 pF. The capacitor may be tied to either VEE or ground, but
using VEE increases negative supply rejection. (Fluctuations in the
negative supply have more effect on accuracy than do any changes
in the positive supply.)
A negative reference voltage may be used if R14 is grounded and
the reference voltage is applied to R15, as shown in Figure 5. A high
input impedance is the main advantage of this method. The negative
reference voltage must be at least 3.0 V above the VEE 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.
Capacitive bypass to ground is recommended when a DC reference
voltage is used. The 5.0 V logic supply is not recommended as a
reference voltage, but if a well regulated 5.0 V supply which drives
logic is to be used as the reference, R14 should be formed of two
series resistors and the junction of the two resistors bypassed with
0.1 µF to ground. For reference voltages greater than 5.0 V, 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.
A1
A2
A3
A4
A5
A6
A7
A8
5
6
7
8
9
10
11
12
3
MC1408
13
14
15
1
2
4
16
SEE TEXT FOR VALUES OF C.
C
R14 = R15
(–)VREF
R14
R15
RL
IO
VEE
VCC
SL00052
Figure 5. Negative VREF
Output Voltage Range
The voltage at Pin 4 must always be at least 4.5 V more positive
than the voltage of the negative supply (Pin 3) when the reference
current is 2 mA or less, and at least 8 V more positive than the
negative supply when the reference current is between 2 mA and
4 mA. This is necessary to avoid saturation of the output transistors,
which would cause serious degradation of accuracy.
Philips Semiconductors MC1408-8 does not need a range control
because the design extends the compliance range down to 4.5 V (or
8 V — see above) above the negative supply voltage without
significant degradation of accuracy. Philips Semiconductors
MC1408-8 can be used in sockets designed for other
manufacturers’ MC1408 without circuit modification.
Philips Semiconductors Product data
MC1408-88-bit multiplying D/A converter
2001 Aug 03 6
Output Current Range
Any time the full-scale current exceeds 2 mA, the negative supply
must be at least 8 V more negative than the output voltage. This is
due to the increased internal voltage drops between the negative
supply and the outputs with higher reference currents.
Accuracy
Absolute accuracy is the measure of each output current level with
respect to its intended value, and is dependent upon relative
accuracy, full-scale accuracy and full-scale current drift. Relative
accuracy is the measure of each output current level as a fraction of
the full-scale current after zero-scale current has been nulled out.
The relative accuracy of the MC1408-8 is essentially constant over
the operating temperature range because of 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 MC1408-8 has a very low
full-scale current drift over the operating temperature range.
The MC1408-8 series is guaranteed accurate to within ±1/2 LSB at
+25 °C at a full-scale output current of 1.99 mA. The relative
accuracy test circuit is shown in Figure 6. The 12-bit converter is
calibrated to a full-scale output current of 1.99219 mA; then the
MC1408-8’s 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 the
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
accurate D-to-A converter. 16-bit accuracy implies a total of
±1/2 part in 65,536, or ±0.00076%, which is much more accurate
than the ±0.19% specification of the MC1408-8.
Monotonicity
A monotonic converter is one which always provides an analog
output greater than or equal to the preceding value for a
corresponding increment in the digital input code. The MC1408-8 is
monotonic for all values of reference current above 0.5 mA. The
recommended range for operation is a DC reference current
between 0.5 mA and 4.0 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
input bits. This time is typically 70 ns for settling to within 1/2LSB for
8-bit accuracy. This time applies when RL < 500 Ω and CO < 25 pF.
The slowest single switch is the least significant bit, which typically
turns on and settles in 65 ns. In applications where the D-to-A
converter functions in a positive going ramp mode, the worst-case
condition does not occur and settling times less than 70 ns may be
realized.
Extra care must be taken in board layout since this usually is the
dominant factor in satisfactory test results when measuring settling
time. Short leads, 100 µF supply bypassing for low frequencies,
minimum scope lead length, good ground planes, and avoidance of
ground loops are all mandatory.
MSB
A1
A2
A3
A4
A5
A6
A7
A8A9 A10 A11 A12
12-BIT
D-TO-A
CONVERTER
ERROR MAX)
0 TO +10V OUTPUT
5k
50k
ERROR (1V = 1%)
NE530
LSB
100 950
5
6
7
8
9
10
11
12
MSB
LSB
MC1408
8-BIT
COUNTER
15 16 3 2 1
4
14 13
–
+
1k C
(±0.02%
VCC
VREF = 2V
VEE
0.1µF
R14
SL00053
Figure 6. Relative Accuracy
Philips Semiconductors Product data
MC1408-88-bit multiplying D/A converter
2001 Aug 03 7
5
6
7
8
9
10
11
12
3
MC1408
13
14
15
1
2
4
16
51
CO ≤ 25pF
R14
0.1µF
RL
eIN
VEE
VCC
15pF
0.1µF
1.0k
1.0k
0.1µF
eO
FOR SETTLING TIME
MEASUREMENT
(ALL BITS
SWITCHED LOW
TO HIGH)
2.4V
0.4V
1.0V
SETTLING TIME
0
0
TRANSIENT
RESPONSE
–100
mV
FOR TURN OFF
MEASUREMENT
USE RL to GND
1.4V
RL = 50Ω
PIN 4 TO GND
tS = 70ns TYPICAL
TO ±1/2LSB
tPLH tPHL
tPHL = tPLH = 10ns
RL = 500Ω
eIN
+2VDC
SL00054
Figure 7. T ransient Response and Settling T ime
INPUTS
5
6
7
8
9
10
11
12
3
MC1408
13 14
15
1
2
4
16
VEE
VCC
THE RESISTOR TIED TO PIN 15 IS TO TEMPERATURE COMPENSATE THE
BIAS CURRENT AND MAY NOT BE NECESSARY FOR ALL APPLICATIONS
VI AND II APPLY TO INPUTS A1 THROUGH A8
IO+KA1
2)
A2
4)
A3
8)
A4
16 )
A5
32 )
A6
64 )
A7
128 )
A8
256
where K +
VREF
R14
and AN = “1” IF AN IS AT HIGH LEVEL
AN = “0” IF AN IS AT LOW LEVEL
DIGITAL
IEE
IO
I15
I14 R14
R15
VO
OUTPUT
RL
VIII
(+)
ICC
VREF(+)
(SEE TEXT FOR VALUES OF C.)
TYPICAL VALUES R14 = R15 = 1k
VREF = +2.0V
C = 15pF
A1
A2
A3
A4
A5
A6
A7
A8
SL00055
Figure 8. Notation Definitions
2.0mA
5
6
7
8
9
10
11
12
3
13
14
15
1
2
4
16
VCC
SCOPE
RL = 50
VREF
MC1408
VEE
15pF
1k
1k
SLEWING TIME
10%
90% 0
dI
dt +I
RL
dV
dt
SL00056
Figure 9. Reference Current Slew Rate Measurement
Philips Semiconductors Product data
MC1408-88-bit multiplying D/A converter
2001 Aug 03 8
DIP16: plastic dual in-line package; 16 leads (300 mil) SOT38-4
Philips Semiconductors Product data
MC1408-88-bit multiplying D/A converter
2001 Aug 03 9
SO16: plastic small outline package; 16 leads; body width 3.9 mm SOT109-1
Philips Semiconductors Product data
MC1408-88-bit multiplying D/A converter
2001 Aug 03 10
Definitions
Short-form specification — The data in a short-form specification is extracted from a full data sheet with the same type number and title. For
detailed information see the relevant data sheet or data handbook.
Limiting values definition — Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 60134). Stress above one
or more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation of the device at these or
at any other conditions above those given in the Characteristics sections of the specification is not implied. Exposure to limiting values for extended
periods may af fect device reliability.
Application information — Applications that are described herein for any of these products are for illustrative purposes only. Philips
Semiconductors make no representation or warranty that such applications will be suitable for the specified use without further testing or
modification.
Disclaimers
Life support — These products are not designed for use in life support appliances, devices or systems where malfunction of these products can
reasonably be expected to result in personal injury . Philips Semiconductors customers using or selling these products for use in such applications
do so at their own risk and agree to fully indemnify Philips Semiconductors for any damages resulting from such application.
Right to make changes — Philips Semiconductors reserves the right to make changes, without notice, in the products, including circuits, standard
cells, and/or software, described or contained herein in order to improve design and/or performance. Philips Semiconductors assumes no
responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright, or mask work right to these
products, and makes no representations or warranties that these products are free from patent, copyright, or mask work right infringement, unless
otherwise specified.
Contact information
For additional information please visit
http://www.semiconductors.philips.com. Fax: +31 40 27 24825
For sales offices addresses send e-mail to:
sales.addresses@www.semiconductors.philips.com.
Koninklijke Philips Electronics N.V. 2002
All rights reserved. Printed in U.S.A.
Date of release: 01-02
Document order number: 9397 750 09381
Data sheet status[1]
Objective data
Preliminary data
Product data
Product
status[2]
Development
Qualification
Production
Definitions
This data sheet contains data from the objective specification for product development.
Philips Semiconductors reserves the right to change the specification in any manner without notice.
This data sheet contains data from the preliminary specification. Supplementary data will be
published at a later date. Philips Semiconductors reserves the right to change the specification
without notice, in order to improve the design and supply the best possible product.
This data sheet contains data from the product specification. Philips Semiconductors reserves the
right to make changes at any time in order to improve the design, manufacturing and supply.
Changes will be communicated according to the Customer Product/Process Change Notification
(CPCN) procedure SNW-SQ-650A.
Data sheet status
[1] Please consult the most recently issued data sheet before initiating or completing a design.
[2] The product status of the device(s) described in this data sheet may have changed since this data sheet was published. The latest information is available on the Internet at URL
http://www.semiconductors.philips.com.
