®
®
DAC-HF Series
Ultra-Fast, 8/10/12-Bit
Digital-to-Analog Converters
INNOVATION and EXCELLENCE
FEATURES
•
•
•
•
•
•
•
8, 10 and 12-Bit resolutions
Settling times to 25ns
±20ppm/°C max. gain tempco
Unipolar or bipolar operation
Current output
Internal feedback resistors
High-reliability MIL-STD-883 models
GENERAL DESCRIPTION
The DAC-HF Series of hybrid DAC’s are ultra high-speed,
current output devices. They incorporate state-of-the-art
performance in a miniature package, achieving maximum
output settling times of 25ns for the 8 and 10-bit models and
50ns for the 12-bit model. They can be used to drive a
resistor load directly for up to ±1V output or a fast operational
ampifier (such as DATEL’s AM-500) for higher voltage outputs
with sub-microsecond settling times. A tapped feedback
resistor and a bipolar offset resistor are included internally to
give five programmable output voltage ranges with an
external operational amplifier.
The DAC-HF design combines proven hybrid construction
techniques with advanced circuit design to realize high-speed
current switching. The design incorporates fast PNP current
switches driving a low-impedance R-2R thin-film ladder
network. The nichrome thin-film resistor network is
deposited by electron beam evaporation on a low-
capacitance substrate to assure high-speed performance.
The resistors are then functionally trimmed by laser for
optimum linearity.
INPUT/OUTPUT CONNECTIONS, DAC-HF12B
PIN
1
2
3
4
5
6
7
8
9
10
11
12
FUNCTION
BIT 1 (MSB)
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
BIT 7
BIT 8
BIT 9 *
BIT 10 *
BIT 11 *
BIT 12 (LSB) *
PIN
24
23
22
21
20
19
18
17
16
15
14
13
FUNCTION
+15V SUPPLY
GROUND
–15V SUPPLY
REFERENCE OUT
BIPOLAR OFFSET
10V RANGE
OUTPUT
20V RANGE
REFERENCE IN
GROUND
GROUND
GROUND
* See note in Figure 1
+15V SUPPLY
24
–15V SUPPLY
22
GROUNDS
13 14 15 23
–10V
REFERENCE
4kW
21
REFERENCE OUT
(–10.05V±0.05V)
BIPOLAR
OFFSET
20
2kW
2kW
THIN-FILM R-2R
LADDER NETWORK
17 20V RANGE
19 10V RANGE
18 OUTPUT
FAST PNP
CURRENT SWITCHES
REFERENCE
CONTROL
CIRCUIT
16 REFERENCE IN
PIN 1
BIT 1
MSB
2 3 4
2 3 4
8 9 10 11 12
8 9 10 11 12
* * * *
LSB
DIGITAL INPUTS
5
5
6
6
7
7
* FOR DAC-HF10B, PINS 11 & 12 ARE NO CONNECTION
FOR DAC-HF8B, PINS 9, 10, 11 & 12 ARE NO CONNECTION
Figure 1. Functional Block Diagram
®
®
DAC-HF Series
ABSOLUTE MAXIMUM RATINGS, ALL MODELS
Positive Supply, Pin 24
Negative Supply, Pin 22
Digital Input Voltage, Pins 1–12
Lead Temperature (soldering, 10s)
+18V
–18V
+15V
300°C
TECHNICAL NOTES
1. Proper operation of the DAC-HF Series converters is
dependent on good board layout and connection practices.
Bypass supplies as shown in the connection diagrams.
Mount bypass capacitors close to the converter, directly to
the supply pins where possible.
2. Use of a ground plane is particularly important in high-
speed D/A converters as it reduces high-frequency noise
and aids in decoupling the digital inputs from the analog
output. Avoid ground loop problems by connecting all
grounds on the board to the ground plane. The remainder
of the ground plane should include as much of the circuit
board as possible.
3. When the converter is configured for voltage output with an
external operational amplifier, keep the leads from the
converter to the output amplifier as short as possible.
4. The high-speed current switching technique used in the
DAC-HF Series inherently reduces the amplitude and
duration of large transient spikes at the output (“glitches”).
The most severe glitches occur at half-scale, the major
carry transition from 011 … 1 to 100 … 0 or vice versa. At
this time, a skewing of the input codes can create a
transition state code of 111 … 1. The duration of the
“transition state code” is dependent on the degree of
skewing, but its effect is dependent on the speed of the
DAC (an ultra-fast DAC will respond to these brief
spurious inputs to a greater degree than a slow DAC).
Minimize the effects of input skewing by using a high-
speed input register to match input switching times. The
input register recommended for use with the DAC-HF is
easily implemented with two Texas Instruments
SN74S174 hex D-type flip-flops. This register will reduce
glitches to a very low level and ensure fast output settling
times.
5. Test the DAC-HF using a low-capacitance test probe (such
as a 10X probe). Take care to assure the shortest
possible connection between probe ground and circuit
ground. Long probe ground leads may pick up
environmental E.M.I. causing artifacts on the scope
display, i.e., signals that do not originate at the unit under
test.
50mA
17mA
FUNCTIONAL SPECIFICATIONS
DESCRIPTION
INPUTS
Resolution,
Bits
Coding,
Unipolar Output
Coding,
Bipolar Output
Input Logic Level,
Bit ON ("1")
Input Logic Level,
Bit OFF ("0")
PERFORMANCE
Nonlinearity Error,
max.
T
MIN
to T
MAX
Differential Nonlinearity Error,
max.
T
MIN
to T
MAX
Monotonicity
Gain Tempco,
max.
Offset Tempco,
Bipolar, max.
Zero Tempco,
max.
Settling Time,
ns max.
➂
Power Supply Sensitivity
OUTPUTS
Output
Output
Output
Output
Current Range,
Unipolar
Current Range,
Bipolar
Compliance Voltage
Voltage Ranges
➀
(Typical at +25°C and ±15V supplies unless otherwise noted.)
8B
10B
12B
8
10
12
Straight binary
Offset binary
+2.0V to +5.5V at +40μA
0V to +0.8V at –2.6mA
±0.012%
±0.024%
±0.012%
±0.024%
Guaranteed over oper. temp. range
±20ppm/°C
±10ppm/°C of FSR
➁
±1.5ppm/°C of FSR
➁
25
25
50
±0.01%/% Supply
0 to +5mA
±2.5mA
±1.2V
0 to –5V
0 to –10V
±2.5V
±5V
±10V
400 Ohms ±10%
15pF
15nA
±15V ±0.5V
40mA
45mA
17mA
17mA
Output Resistance
Output Capacitance
Output Leakage Current,
All Bits OFF
POWER REQUIREMENTS
Supply Voltages
Positive Quiescent Current,
max.
Negative Quiescent Current,
max.
PHYSICAL ENVIRONMENTAL
Operating Temperature Range,
Case
Storage Temperature Range
Package Type
Weight
Footnotes
0°C to +70°C (BMC)
–55°C to +125°C (BMM, 883)
–65°C to +150°C
24-pin ceramic DDIP
0.22 ounces (6.3 grams)
6. Passive components used with the DAC-HF may be as
indicated here: 0.1μF and 1μF bypass capacitors should
be ceramic type and tantalum type respectively; the 400Ω
output load is a ±0.1%, 10ppm/°C, metal-film type;
adjustment potentiometers are ceremet types; other
resistors may be ±10% carbon composition types.
7. Output voltage compliance is ±1.2V to preserve the
linearity of the converter. In the bipolar mode, the DAC-HF
can be operated with no load to give an output voltage of
±1.0V. In the unipolar mode, the load resistance must be
less than 600Ω to give less than +1.2V output. The
specified output currents of 0 to +5mA and ±2.5mA are
measured into a short circuit or an operational amplifier
summing junction.
➀
With external operational amplifier.
➁
FSR is Full Scale Range, or the difference between minimum
and maximum output values.
➂
Full-scale current change to ±1LSB with 400Ω load.
®
®
DAC-HF Series
CALIBRATION PROCEDURE
Unipolar Output Current
1. Connect the converter as shown in Figure 2.
2. Set all inputs low and adjust the ZERO ADJUST
potentiometer for a reading of 0V at the output.
3. Set all inputs high and adjust the GAIN ADJUST
potentiometer for a reading of –F.S. + 1LSB (See Table 1).
Bipolar Output Current
1. Connect the converter as shown in Figure 3.
2. Set all inputs low and adjust the OFFSET ADJUST and
LOAD potentiometer for an output reading of +F.S. (See
Table 2).
3. Set all inputs high and adjust the GAIN ADJUST potentiom-
eter for an output reading of –F.S. + 1LSB (See Table 2).
+15V
+
0.1µF
1µF
Table 1. 12-Bit Unipolar Output Coding
ANALOG OUTPUT
UNIPOLAR
INPUT CODING
SCALE
STRAIGHT BINARY 0 to 1V F.S. 0 to –5V F.S. 0 to –10V F.S.
–F.S. + 1LSB
–3/4F.S.
–1/2F.S.
–1/4F.S.
–1LSB
0
1111 1111 1111
1100 0000 0000
1000 0000 0000
0100 0000 0000
0000 0000 0001
0000 0000 0000
+0.9998V
+0.7500V
+0.5000V
+2.5000V
+0.0002V
0.0000V
–4.9988V
–3.7500V
–2.5000V
–1.2500V
–0.0012V
0.0000V
–9.9976V
–7.5000V
–5.0000V
–2.5000V
–0.0024V
0.0000V
Table 2. 12-Bit Bipolar Output Coding
BIPOLAR
SCALE
–F.S. + 1LSB
–1/2F.S.
–1LSB
0
+1/2F.S.
+F.S. – 1LSB
+F.S.
ANALOG OUTPUT
INPUT CODING
OFFSET
±0.5V F.S. ±2.5V F.S. ±5V F.S.
BINARY
1111 1111 1111
1100 0000 0000
1000 0000 0001
1000 0000 0000
0100 0000 0000
0000 0000 0001
0000 0000 0000
+0.4998V
+0.1250V
+0.0002V
0.0000V
–0.1250V
–0.4998V
–0.5000V
–2.4988V
–1.2500V
–0.0012V
0.0000V
+1.2500V
+2.4988V
+2.5000V
±10V F.S.
–9.9951V
–5.0000V
–0.0049V
0.0000V
+5.0000V
+9.9951V
+10.0000V
–4.9976V
–2.5000V
–0.0024V
0.0000V
+2.5000V
+4.9976V
+5.0000V
24
BIT 1
1
19
17
18
100W
200W
20
OFFSET
ADJUST
370W
100W
16
15
14
12
BIT 12
23
22
13
LOAD
(444W NOMINAL)
(FOR 0 TO ±0.5V FS)
I
OUT
OUTPUT
Table 3. Programmable Output Range Pin Connections
FEEDBACK
OUTPUT VOLTAGE
CONNECTIONS
RANGE
0 to –5V
0 to –10V
±2.5V
±5V
±10V
PIN 19
PIN 19
PIN 19
PIN 19
PIN 17
CONNECT THESE
PINS TOGETHER
PIN 17 to PIN 18 / PIN 20 to PIN 23
PIN 20 to PIN 23
PIN 17 to PIN 18 / PIN 20 to PIN 18
PIN 20 to PIN 18
PIN 20 to PIN 18
DAC-HF
21
GAIN
ADJUST
In all programmable output ranges, pin 18 connects to
external operational amplifier inverting input.
4k = 0.1%
20
BIPOLAR
OFFSET
REF OUT
(–10V = 2%)
2kΩ FEEDBACK
(10V RANGE)
4kΩ FEEDBACK
(20V RANGE)
–15V
0.1µF
+
21
1µF
19
Figure 3. Bipolar Current Output Connections
+15V
+
0.1µF
1µF
+15V
24
BIT 1
1
19
17
18
I
OUT
400W LOAD
(FOR 0 TO
+1V FS)
2MW
ZERO
ADJUST
25kW
–15V
OUTPUT
2k
2k
17
18 OUTPUT
400Ω, ±10%
5mA
23 GROUND
Figure 4. Equivalent Output Circuit
20
DAC-HF
21
100W
16
15
14
12
BIT 12
23
22
13
2V/DIV
–15V
0.1µF
+
50nsec/DIV
2V/DIV
GAIN
ADJUST
50nsec/DIV
1µF
DAC-HF with AM-500, ±5V output full scale (10V) step
Figure 2. Unipolar Current Output Connections
Figure 5. Voltage Output Waveforms
®
®
DAC-HF Series
+ 1 5 V
0 .1 µ F
+
1 µ F
APPLICATIONS
0 .1 µ F
+
+ 1 5 V
1 µ F
2 4
B IT 1
1
1 9
1 7
1 8
*
*
F E E D B A C K ; S e e p r o g r a m m a b le
o u tp u t r a n g e c o n n e c tio n s , T a b le 3 .
B IT 1
1
2 4
1 9
1 7
*
*
F E E D B A C K ; S e e p r o g r a m m a b le
o u tp u t r a n g e c o n n e c tio n s , T a b le 3 .
4
A M -5 0 0
5
1 0
O U T P U T
1 8
2
A M -4 5 2
3
7
1
5
O F F S E T
A D J U S T
1 0 0
Ω
G A IN
A D J U S T
2 0 k
Ω
1 5 V
6
O U T P U T
2 0
+ 1 5 V
7 5 0 k
1 0 0
Ω
G A IN
A D J U S T
R
Z E R O
A D J U S T
2 0 k
9
1 5 V
R
F E E D B A C K
x 4 0 0
R
F E E D B A C K
+ 4 0 0
1 2
2 0
D A C -H F
2 1
D A C -H F
2 1
1 6
1 5
1 4
1 2
B IT 1 2
2 3
2 2
1 3
R =
1 6
1 5
1 4
1 3
2 3
2 2
B IT 1 2
OUTPUT
STEP
1 5 V
TYPICAL SETTLING
TIME TO 1LSB
300ns
200ns
150ns
OUTPUT
STEP
1 5 V
TYPICAL SETTLING
TIME TO 1LSB
2μs
600ns
400ns
0 .1 µ F
+
1 µ F
20V
10V
5V
0 .1 µ F
+
1 µ F
20V
10V
5V
Figure 6. Unipolar Ultra-Fast Voltage Output Circuit
Figure 7. Unipolar Fast Voltage Output Circuit
MECHANICAL DIMENSIONS
INCHES (mm)
1.31 MAX.
(33.27)
Dimension Tolerances
(unless otherwise indicated):
2 place decimal (.XX) ±0.010 (±0.254)
3 place decimal (.XXX) ±0.005 (±0.127)
0.80 MAX.
(20.32)
1
12
Lead Material:
Kovar alloy
Lead Finish:
50 microinches (minimum) gold plating
over 100 microinches (nominal) nickel plating
ORDERING INFORMATION
MODEL
DAC-HF8BMC
DAC-HF8BMM
DAC-HF8/883
➀
DAC-HF10BMC
DAC-HF10BMM
DAC-HF10/883
➀
DAC-HF12BMC
DAC-HF12BMM
DAC-HF12/883
➀
OPERATING
TEMP. RANGE
0 to +70°C
–55 to +125°C
–55 to +125°C
0 to +70°C
–55 to +125°C
–55 to +125°C
0 to +70°C
–55 to +125°C
–55 to +125°C
BITS
8
8
8
10
10
10
12
12
12
24
13
0.100 TYP.
(2.540)
1.100
(27.940)
0.235 MAX.
(5.969)
0.200 MAX.
(5.080)
0.010
–0.001
(0.254)
0.190 MAX.
(4.826)
0.018 ±0.002
(0.457)
0.100
(2.540)
0.040
(1.016)
+0.002
SEATING
PLANE
0.025
(0.635)
0.600 ±0.010
(15.240)
0.100
(2.540)
®
®
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C&D Technologies, Inc. makes no representation that the use of its products in the circuits described
herein, or the use of other technical information contained herein, will not infringe upon existing or future
patent rights. The descriptions contained herein do not imply the granting of licenses to make, use, or sell
equipment constructed in accordance therewith. Specifications are subject to change without notice.
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