DAC7614
DAC7614
DAC7614
®
© 1998 Burr-Brown Corporation PDS-1445C Printed in U.S.A. December, 1998
Quad, Serial Input, 12-Bit, Voltage Output
DIGITAL-TO-ANALOG CONVERTER
FEATURES
● LOW POWER: 20mW
● UNIPOLAR OR BIPOLAR OPERATION
●SETTLING TIME: 10µs to 0.012%
● 12-BIT LINEARITY AND MONOTONICITY:
–40°C to +85°C
●USER SELECTABLE RESET TO MID-
SCALE OR ZERO-SCALE
● SECOND-SOURCE for DAC8420
● SMALL 20-LEAD SSOP PACKAGE
APPLICATIONS
● ATE PIN ELECTRONICS
● PROCESS CONTROL
● CLOSED-LOOP SERVO-CONTROL
● MOTOR CONTROL
● DATA ACQUISITION SYSTEMS
DESCRIPTION
The DAC7614 is a quad, serial input, 12-bit, voltage
output digital-to-analog converter (DAC) with guar-
anteed 12-bit monotonic performance over the –40°C
to +85°C temperature range. An asynchronous reset
clears all registers to either mid-scale (800H) or zero-
scale (000H), selectable via the RESETSEL pin. The
device can be powered from a single +5V supply or
from dual +5V and –5V supplies.
International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111
Twx: 910-952-1111 • Internet: http://www.burr-brown.com/ • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132
Low power and small size makes the DAC7614 ideal
for process control, data acquisition systems, and
closed-loop servo-control. The device is available in
16-pin plastic DIP, 16-lead SOIC, or 20-lead SSOP
packages, and is guaranteed over the –40°C to +85°C
temperature range.
DAC A
DAC
Register A
DAC B
DAC
Register B
DAC C
DAC
Register C
DAC D
DAC
Register D
V
REFH
V
DD
V
SS
V
OUTD
V
OUTC
V
OUTB
V
OUTA
V
REFL
GND
CLK
CS
12
SDI
RESET RESETSELLOADDACS
Serial-to-
Parallel
Shift
Register
DAC
Select
®
2
DAC7614
SPECIFICATIONS
At TA = –40°C to +85°C, VDD = +5V, VSS = –5V, VREFH = +2.5V, and VREFL = –2.5V, unless otherwise noted.
DAC7614E, P, U DAC7614EB, PB, UB
PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS
ACCURACY
Linearity Error(1) VSS = 0V or –5V ±2±1 LSB(2)
Linearity Matching(3) VSS = 0V or –5V ±2±1 LSB
Differential Linearity Error VSS = 0V or –5V ±1±1 LSB
Monotonicity 12 ✻Bits
Zero-Scale Error Code = 000H±4✻LSB
Zero-Scale Drift 25 ✻✻ppm/°C
Zero-Scale Matching(3) ±2±1 LSB
Full-Scale Error Code = FFFH±4✻LSB
Full-Scale Matching(3) ±2±1 LSB
Zero-Scale Error Code = 00AH, VSS = 0V ±8✻LSB
Zero-Scale Drift VSS = 0V 5 10 ✻✻ppm/°C
Zero-Scale Matching(3) VSS = 0V ±4±2 LSB
Full-Scale Error Code = FFFH, VSS = 0V ±8✻LSB
Full-Scale Matching(3) VSS = 0V ±4±2 LSB
Power Supply Rejection 30 ✻ppm/V
ANALOG OUTPUT
Voltage Output(4) VSS = 0V or –5V VREFL VREFH ✻✻V
Output Current –1.25 +1.25 ✻✻mA
Load Capacitance No Oscillation 100 ✻pF
Short-Circuit Current +5, –15 ✻mA
Short-Circuit Duration
Indefinite
✻
REFERENCE INPUT
VREFH Input Range VSS = 0V or –5V
VREFL+1.25
+2.5 ✻✻V
VREFL Input Range VSS = 0V 0
VREFH–1.25
✻✻V
VREFL Input Range VSS = –5V –2.5
VREFH–1.25
✻✻V
DYNAMIC PERFORMANCE
Settling Time(5) To ±0.012% 5 10 ✻✻ µs
Channel-to-Channel Crosstalk Full-Scale Step 0.1 ✻LSB
On Any Other DAC, RL = 2kΩ
Output Noise Voltage Bandwidth: 0Hz to 1MHz 40 ✻nV/√Hz
DIGITAL INPUT/OUTPUT
Logic Family TTL-Compatible CMOS ✻
Logic Levels
VIH | IIH | ≤ 10µA 2.4 VDD+0.3 ✻✻V
VIL | IIL | ≤ 10µA –0.3 0.8 ✻✻V
Data Format Straight Binary ✻
POWER SUPPLY REQUIREMENTS
VDD 4.75 5.25 ✻✻V
VSS If VSS ≠ 0V –5.25 –4.75 ✻✻V
IDD 1.5 1.9 ✻✻ mA
ISS –2.1 –1.6 ✻✻ mA
Power Dissipation VSS = –5V 15 20 ✻✻ mW
VSS = 0V 7.5 10 ✻✻ mW
TEMPERATURE RANGE
Specified Performance –40 +85 ✻✻°C
The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes
no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change
without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant
any BURR-BROWN product for use in life support devices and/or systems.
✻ Specification same as grade to the left.
NOTES: (1) If VSS = 0V, specification applies at code 00AH and above. (2) LSB means Least Significant Bit, with VREFH equal to +2.5V and VREFL equal to –2.5V,
one LSB is 1.22mV. (3) All DAC outputs will match within the specified error band. (4) Ideal output voltage, does not take into account zero or full-scale error.
(5) If VSS = –5V, full-scale step from code 000H to FFFH or vice-versa. If VSS = 0V, full-scale positive step from code 000H to FFFH and negative step from code
FFFH to 00AH.
3
®
DAC7614
ABSOLUTE MAXIMUM RATINGS(1)
VDD to VSS ........................................................................... –0.3V to +11V
VDD to GND ........................................................................ –0.3V to +5.5V
VREFL to VSS ...............................................................–0.3V to (VDD – VSS)
VDD to VREFH ..............................................................–0.3V to (VDD – VSS)
VREFH to VREFL ............................................................–0.3V to (VDD – VSS)
Digital Input Voltage to GND...................................... –0.3V to VDD + 0.3V
Maximum Junction Temperature ................................................... +150°C
Operating Temperature Range ......................................... –40°C to +85°C
Storage Temperature Range .......................................... –65°C to +150°C
Lead Temperature (soldering, 10s) ............................................... +300°C
NOTE: (1) Stresses above those listed under “Absolute Maximum Ratings” may
cause permanent damage to the device. Exposure to absolute maximum
conditions for extended periods may affect device reliability.
ELECTROSTATIC
DISCHARGE SENSITIVITY
This integrated circuit can be damaged by ESD. Burr-Brown
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
MAXIMUM MAXIMUM
LINEARITY DIFFERENTIAL PACKAGE SPECIFICATION
ERROR LINEARITY DRAWING TEMPERATURE ORDERING TRANSPORT
PRODUCT (LSB) (LSB) PACKAGE NUMBER(1) RANGE NUMBER(2) MEDIA
DAC7614P ±2±1 16-Pin DIP 180 –40°C to +85°C DAC7614P Rails
DAC7614PB ±1""" "DAC7614PB Rails
DAC7614U ±2±1 16-Lead SOIC 211 –40°C to +85°C DAC7614U Rails
"" """ "DAC7614U/1K Tape and Reel
DAC7614UB ±1±1 16-Lead SOIC 211 –40°C to +85°C DAC7614UB Rails
"" """ "DAC7614UB/1K Tape and Reel
DAC7614E ±2±1 20-Lead SSOP 334 –40°C to +85°C DAC7614E Rails
"" """ "DAC7614E/1K Tape and Reel
DAC7614EB ±1±1 20-Lead SSOP 334 –40°C to +85°C DAC7614EB Rails
"" """ "DAC7614EB/1K Tape and Reel
NOTES: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. (2) Models with a slash (/) are
available only in Tape and Reel in the quantities indicated (e.g., /1K indicates 1000 devices per reel). Ordering 1000 pieces of “DAC7614EB/1K” will get a single
1000-piece Tape and Reel. For detailed Tape and Reel mechanical information, refer to Appendix B of Burr-Brown IC Data Book.
®
4
DAC7614
PIN CONFIGURATION—P, U Packages
Top View PDIP, SOIC
PIN DESCRIPTIONS—P, U Packages
PIN LABEL DESCRIPTION
1V
DD Positive Analog Supply Voltage, +5V nominal.
2V
OUTD DAC D Voltage Output
3V
OUTC DAC C Voltage Output
4V
REFL Reference Input Voltage Low. Sets minimum out-
put voltage for all DACs.
5V
REFH Reference Input Voltage High. Sets maximum out-
put voltage for all DACs.
6V
OUTB DAC B Voltage Output
7V
OUTA DAC A Voltage Output
8V
SS Negative Analog Supply Voltage, 0V or –5V nomi-
nal.
9 GND Ground
10 SDI Serial Data Input
11 CLK Serial Data Clock
12 CS Chip Select Input
13 NIC Not Internally Connected.
14 LOADDACS The selected DAC register becomes transparent
when LOADDACS is LOW. It is in the latched state
when LOADDACS is HIGH.
15 RESET Asynchronous Reset Input. Sets all DAC registers
to either zero-scale (000H) or mid-scale (800H)
when LOW. RESETSEL determines which code is
active.
16 RESETSEL When LOW, a LOW on RESET will cause all DAC
registers to be set to code 000H. When RESETSEL
is HIGH, a LOW on RESET will set the registers to
code 800H.
PIN CONFIGURATION—E Package
Top View SSOP
PIN DESCRIPTIONS—E Package
PIN LABEL DESCRIPTION
1V
DD Positive Analog Supply Voltage, +5V nominal.
2V
OUTD DAC D Voltage Output
3V
OUTC DAC C Voltage Output
4V
REFL Reference Input Voltage Low. Sets minimum out-
put voltage for all DACs.
5 NIC Not Internally Connected.
6 NIC Not Internally Connected.
7V
REFH Reference Input Voltage High. Sets maximum out-
put voltage for all DACs.
8V
OUTB DAC B Voltage Output.
9V
OUTA DAC A Voltage Output.
10 VSS Negative Analog Supply Voltage, 0V or –5V nomi-
nal.
11 GND Ground
12 SDI Serial Data Input
13 CLK Serial Data Clock
14 CS Chip Select Input
15 NIC Not Internally Connected.
16 NIC Not Internally Connected.
17 NIC Not Internally Connected.
18 LOADDACS The selected DAC register becomes transparent
when LOADDACS is LOW. It is in the latched state
when LOADDACS is HIGH.
19 RESET Asynchronous Reset Input. Sets all DAC registers
to either zero-scale (000H) or mid-scale (800H)
when LOW. RESETSEL determines which code is
active.
20 RESETSEL When LOW, a LOW on RESET will cause all DAC
registers to be set to code 000H. When RESETSEL
is HIGH, a LOW on RESET will set the registers to
code 800H.
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
DD
V
OUTD
V
OUTC
V
REFL
V
REFH
V
OUTB
V
OUTA
V
SS
RESETSEL
RESET
LOADDACS
NIC
CS
CLK
SDI
GND
DAC7614P, U
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
V
DD
V
OUTD
V
OUTC
V
REFL
NIC
NIC
V
REFH
V
OUTB
V
OUTA
V
SS
RESETSEL
RESET
LOADDACS
NIC
NIC
NIC
CS
CLK
SDI
GND
DAC7614E
5
®
DAC7614
TYPICAL PERFORMANCE CURVES: VSS = 0V
At TA = +25°C, VDD = +5V, VSS = 0V, VREFH = +2.5V, and VREFL = 0V, representative unit, unless otherwise specified.
LINEARITY ERROR and
DIFFERENTIAL LINEARITY ERROR vs CODE
(DAC A)
200
H
000
H
Digital Input Code
DLE (LSB) LE (LSB)
0.50
0.00
–0.25
–0.50
0.50
0.25
0.00
–0.50
–0.25
0.25
400
H
600
H
800
H
A00
H
C00
H
E00
H
FFF
H
LINEARITY ERROR and
DIFFERENTIAL LINEARITY ERROR vs CODE
(DAC B)
000
H
Digital Input Code
DLE (LSB) LE (LSB)
0.50
0.00
–0.25
–0.50
0.50
0.25
0.00
–0.50
–0.25
0.25
200
H
400
H
600
H
800
H
A00
H
C00
H
E00
H
FFF
H
LINEARITY ERROR and
DIFFERENTIAL LINEARITY ERROR vs CODE
(DAC C)
000
H
Digital Input Code
DLE (LSB) LE (LSB)
0.50
0.00
–0.25
–0.50
0.50
0.25
0.00
–0.50
–0.25
0.25
200
H
400
H
600
H
800
H
A00
H
C00
H
E00
H
FFF
H
LINEARITY ERROR and DIFFERENTIAL
LINEARITY ERROR vs CODE
(DAC D)
000
H
Digital Input Code
DLE (LSB) LE (LSB)
0.50
0.00
–0.25
–0.50
0.50
0.25
0.00
–0.50
–0.25
0.25
200
H
400
H
600
H
800
H
A00
H
C00
H
E00
H
FFF
H
LINEARITY ERROR vs CODE
(DAC A, –40°C and +85°C)
000
H
Digital Input Code
LE (LSB) LE (LSB)
0.50
0.00
–0.25
–0.50
0.50
0.25
0.00
–0.50
–0.25
0.25 +85°C
–40°C
200
H
400
H
600
H
800
H
A00
H
C00
H
E00
H
FFF
H
LINEARITY ERROR vs CODE
(DAC B, –40°C and +85°C)
000
H
Digital Input Code
LE (LSB) LE (LSB)
0.50
0.00
–0.25
–0.50
0.50
0.25
0.00
–0.50
–0.25
0.25 +85°C
–40°C
200
H
400
H
600
H
800
H
A00
H
C00
H
E00
H
FFF
H
®
6
DAC7614
TYPICAL PERFORMANCE CURVES: VSS = 0V (CONT)
At TA = +25°C, VDD = +5V, VSS = 0V, VREFH = +2.5V, and VREFL = 0V, representative unit, unless otherwise specified.
LINEARITY ERROR vs CODE
(DAC C, –40°C and +85°C)
000
H
Digital Input Code
LE (LSB) LE (LSB)
0.50
0.00
–0.25
–0.50
0.50
0.25
0.00
–0.50
–0.25
0.25 +85°C
–40°C
200
H
400
H
600
H
800
H
A00
H
C00
H
E00
H
FFF
H
LINEARITY ERROR vs CODE
(DAC D, –40°C and +85°C)
000
H
Digital Input Code
LE (LSB) LE (LSB)
0.50
0.00
–0.25
–0.50
0.50
0.25
0.00
–0.50
–0.25
0.25 +85°C
–40°C
200
H
400
H
600
H
800
H
A00
H
C00
H
E00
H
FFF
H
POSITIVE SLEW RATE and SETTLING TIME
–2 8–1 Time (µs)
A: Output Voltage (V)
B: Output Voltage, Deviation from +2.5V (LSB)
–0.25
2.25
1.75
2.75
1.25
0.75
0.25
–9
6
3
9
0
–3
–6
01234567
0V
5V
LOADDACS
AB
NEGATIVE SLEW RATE and SETTLING TIME
–2 8–1 Time (µs)
A: Output Voltage (V)
B: Output Voltage, Deviation from Code 00A
H
(LSB)
–0.25
2.25
1.75
2.75
1.25
0.75
0.25
–9
6
3
9
0
–3
–6
01234567
0V
5V
LOADDACS
A
B
7
®
DAC7614
TYPICAL PERFORMANCE CURVES: VSS = –5V
At TA = +25°C, VDD = +5V, VSS = –5V, VREFH = +2.5V, and VREFL = –2.5V, representative unit, unless otherwise specified.
LINEARITY ERROR and
DIFFERENTIAL LINEARITY ERROR vs CODE
(DAC A)
000
H
Digital Input Code
DLE (LSB) LE (LSB)
0.50
0.00
–0.25
–0.50
0.50
0.25
0.00
–0.50
–0.25
0.25
200
H
400
H
600
H
800
H
A00
H
C00
H
E00
H
FFF
H
LINEARITY ERROR and
DIFFERENTIAL LINEARITY ERROR vs CODE
(DAC B)
000
H
Digital Input Code
DLE (LSB) LE (LSB)
0.50
0.00
–0.25
–0.50
0.50
0.25
0.00
–0.50
–0.25
0.25
200
H
400
H
600
H
800
H
A00
H
C00
H
E00
H
FFF
H
LINEARITY ERROR and
DIFFERENTIAL LINEARITY ERROR vs CODE
(DAC C)
000
H
Digital Input Code
DLE (LSB) LE (LSB)
0.50
0.00
–0.25
–0.50
0.50
0.25
0.00
–0.50
–0.25
0.25
200
H
400
H
600
H
800
H
A00
H
C00
H
E00
H
FFF
H
LINEARITY ERROR and
DIFFERENTIAL LINEARITY ERROR vs CODE
(DAC D)
000
H
Digital Input Code
DLE (LSB) LE (LSB)
0.50
0.00
–0.25
–0.50
0.50
0.25
0.00
–0.50
–0.25
0.25
200
H
400
H
600
H
800
H
A00
H
C00
H
E00
H
FFF
H
LINEARITY ERROR vs CODE
(DAC A, –40°C and +85°C)
000
H
Digital Input Code
LE (LSB) LE (LSB)
0.50
0.00
–0.25
–0.50
0.50 +85°C
–40°C
0.25
0.00
–0.50
–0.25
0.25
200
H
400
H
600
H
800
H
A00
H
C00
H
E00
H
FFF
H
LINEARITY ERROR vs CODE
(DAC B, –40°C and +85°C)
000
H
Digital Input Code
LE (LSB) LE (LSB)
0.50
0.00
–0.25
–0.50
0.50 +85°C
–40°C
0.25
0.00
–0.50
–0.25
0.25
200
H
400
H
600
H
800
H
A00
H
C00
H
E00
H
FFF
H
®
8
DAC7614
TYPICAL PERFORMANCE CURVES: VSS = –5V (CONT)
At TA = +25°C, VDD = +5V, VSS = –5V, VREFH = +2.5V, and VREFL = –2.5V, representative unit, unless otherwise specified.
LINEARITY ERROR vs CODE
(DAC C, –40°C and +85°C)
200
H
000
H
Digital Input Code
LE (LSB) LE (LSB)
0.50
0.00
–0.25
–0.50
0.50 +85°C
–40°C
0.25
0.00
–0.50
–0.25
0.25
400
H
600
H
800
H
A00
H
C00
H
E00
H
FFF
H
600
V
REFH
CURRENT vs CODE
(All DACs Set to Indicated Code)
000
H
FFF
H
400
H
C00
H
800
H
Digital Input Code
V
REH
Current (µA)
0
100
200
300
400
500
NEGATIVE SLEW RATE and SETTLING TIME
–2 8–1 Time (µs)
A: Output Voltage (V)
B: Output Voltage, Deviation from –2.5V (LSB)
–3
2
1
3
0
–1
–2
–6
4
2
6
0
–2
–4
01234567
0V
5V
LOADDACS
AB
POSITIVE SLEW RATE and SETTLING TIME
–2 8–1 Time (µs)
A: Output Voltage (V)
B: Output Voltage, Deviation from +2.5V (LSB)
–3
2
1
3
0
–1
–2
–6
4
2
6
0
–2
–4
0 1 2 3 4 5 6 7
0V
5V
LOADDACS
A
B
0
V
REFL
CURRENT vs CODE
(All DACs Set to Indicated Code)
000
H
FFF
H
400
H
C00
H
800
H
Digital Input Code
V
REL
Current (µA)
–600
–500
–400
–300
–200
–100
LINEARITY ERROR vs CODE
(DAC D, –40˚C and +85˚C)
000
H
200
H
Digital Input Code
LE (LSB) LE (LSB)
0.50
0.00
–0.25
–0.50
0.50 +85˚C
–40˚C
0.25
0.00
–0.50
–0.25
0.25
400
H
600
H
800
H
A00
H
C00
H
E00
H
FFF
H
9
®
DAC7614
THEORY OF OPERATION
The DAC7614 is a quad, serial input, 12-bit, voltage output
DAC. The architecture is a classic R-2R ladder configuration
followed by an operational amplifier that serves as a buffer.
Each DAC has its own R-2R ladder network and output op
amp, but all share the reference voltage inputs. The minimum
voltage output (“zero-scale”) and maximum voltage output
(“full-scale”) are set by external voltage references (VREFL
and VREFH, respectively). The digital input is a 16-bit serial
word that contains the 12-bit DAC code and a 2-bit address
code that selects one of the four DACs (the two remaining
bits are unused). The converter can be powered from a single
+5V supply or a dual ±5V supply. Each device offers a reset
function which immediately sets all DAC output voltages and
internal registers to either zero-scale (code 000H) or mid-scale
(code 800H). The reset code is selected by the state of the
RESETSEL pin (LOW = 000H, HIGH = 800H). See Figures
1 and 2 for the basic operation of the DAC7614.
ANALOG OUTPUTS
When VSS = –5V (dual supply operation), the output
amplifier can swing to within 2.25V of the supply rails,
over the –40°C to +85°C temperature range. With VSS = 0V
(single-supply operation), the output can swing to ground.
Note that the settling time of the output op amp will be
longer with voltages very near ground. Also, care must be
taken when measuring the zero-scale error when VSS = 0V.
If the output amplifier has a negative offset, the output
voltage may not change for the first few digital input codes
(000H, 001H, 002H, etc.) since the output voltage cannot
swing below ground.
The behavior of the output amplifier can be critical in some
applications. Under short-circuit conditions (DAC output
shorted to ground), the output amplifier can sink a great deal
more current than it can source. See the Specifications table
for more details concerning short-circuit current.
FIGURE 1. Basic Single-Supply Operation of the DAC7614.
FIGURE 2. Basic Dual-Supply Operation of the DAC7614.
NOTES: (1) P and U package pin configurations shown. (2) As configured, RESET LOW sets all internal registers
to code 000
H
(0V). If RESETSEL is HIGH, RESET LOW sets all internal registers to code 800
H
(1.25V).
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
DD
V
OUTD
V
OUTC
V
REFL
V
REFH
V
OUTB
V
OUTA
V
SS
RESETSEL
RESET
LOADDACS
NIC
CS
CLK
SDI
GND
Reset DACs
(2)
Update Selected Register
Chip Select
Clock
Serial Data In
DAC7614
(1)
0.1µF
0.1µF
0V to +2.5V
1µF to 10µF
+5V
+
0V to +2.5V
0V to +2.5V
0V to +2.5V
+2.500V
NOTES: (1) P and U package pin configurations shown. (2) As configured, RESET LOW sets all internal register
to code 800
H
(0V). If RESETSEL is LOW, RESET LOW sets all internal registers to code 000
H
(–2.5V).
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
DD
V
OUTD
V
OUTC
V
REFL
V
REFH
V
OUTB
V
OUTA
V
SS
RESETSEL
RESET
LOADDACS
NIC
CS
CLK
SDI
GND
Reset DACs
(2)
Update Selected Register
Chip Select
Clock
Serial Data In
DAC7614(1)
0.1µF
0.1µF
–2.5V to +2.5V
1µF to 10µF
+5V
–5V
+
0.1µF
1µF to 10µF
+
–2.5V to +2.5V
–2.500V
0.1µF
+2.500V
–2.5V to +2.5V
–2.5V to +2.5V
+5V
®
10
DAC7614
REFERENCE INPUTS
The reference inputs, VREFL and VREFH, can be any voltage
between VSS + 2.25V and VDD – 2.25V provided that
VREFH is at least 1.25V greater than VREFL. The minimum
output of each DAC is equal to VREFL – 1LSB plus a small
offset voltage (essentially, the offset of the output op amp).
The maximum output is equal to VREFH plus a similar
offset voltage. Note that VSS (the negative power supply)
must either be connected to ground or must be in the range
of –4.75V to –5.25V. The voltage on VSS sets several bias
points within the converter. If VSS is not in one of these two
configurations, the bias values may be in error and proper
operation of the device is not guaranteed.
The current into the reference inputs depends on the DAC
output voltages and can vary from a few microamps to
approximately 0.6 milliamp. Bypassing the reference volt-
age or voltages with a 0.1µF capacitor placed as close as
possible to the DAC7614 package is strongly recommended.
DIGITAL INTERFACE
Figure 3 and Table I provide the basic timing for the
DAC7614. The interface consists of a serial clock (CLK),
serial data (SDI), and a load DAC signal (LOADDACS). In
addition, a chip select (CS) input is available to enable serial
communication when there are multiple serial devices. An
SYMBOL DESCRIPTION MIN TYP MAX UNITS
tDS
Data Valid to CLK Rising
25 ns
tDH
Data Held Valid after CLK Rises
20 ns
tCH
CLK HIGH
30 ns
tCL
CLK LOW
50 ns
tCSS
CS LOW to CLK Rising
55 ns
tCSH
CLK HIGH to CS Rising
15 ns
tLD1
LOADDACS HIGH to CLK Rising
40 ns
tLD2
CLK Rising to LOADDACS LOW
15 ns
tLDDW
LOADDACS LOW Time
45 ns
tRSSH
RESETSEL Valid to RESET LOW
25 ns
tRSTW
RESET LOW Time
70 ns
tS
Settling Time
10 µs
FIGURE 3. DAC7614 Timing.
TABLE I. Timing Specifications (TA = –40°C to +85°C).
asynchronous reset input (RESET) is provided to simplify
start-up conditions, periodic resets, or emergency resets to a
known state.
The DAC code and address are provided via a 16-bit serial
interface as shown in Figure 3. The first two bits select the
DAC register that will be updated when LOADDACS goes
LOW (see Table II). The next two bits are not used. The last
12 bits is the DAC code which is provided, most significant
bit first.
A1
(MSB) (LSB)
SDI
CLK
CS
LOADDAC
A0 X X D11 D10 D9 D3 D2 D1 D0
SDI
CLK
LOADDAC
RESET
V
OUT
tcss
t
LD1
t
CL
t
CH
t
DS
t
DH
t
LD2
t
LDDW
t
LDDW
t
S
t
RSTW
t
RSSH
t
CSH
t
S
1 LSB
ERROR BAND 1 LSB
ERROR BAND
RESETSEL
11
®
DAC7614
STATE OF
SELECTED SELECTED
DAC DAC
A1 A0 LOADDACS RESET REGISTER REGISTER
L(1) L L H A Transparent
L H L H B Transparent
H L L H C Transparent
H H L H D Transparent
X(2) X H H NONE (All Latched)
X X X L ALL Reset(3)
NOTES: (1) L = Logic LOW. (2) X = Don’t Care. (3) Resets to either 000H or
800H, per the RESETSEL state (LOW = 000H, HIGH = 800H). When RESET
rises, all registers that are in their latched state retain the reset value.
TABLE II. Control Logic Truth Table.
CS(1) CLK(1)
LOADDACS
RESET SERIAL SHIFT REGISTER
H(2) X(3) H H No Change
L(4) L H H No Change
L↑(5) H H Advanced One Bit
↑L H H Advanced One Bit
H(6) XL
(7) H No Change
H(6) XHL
(8) No Change
NOTES: (1) CS and CLK are interchangeable. (2) H = Logic HIGH. (3) X =
Don’t Care. (4) L = Logic LOW (5) = Positive Logic Transition. (6) A HIGH
value is suggested in order to avoid a “false clock” from advancing the shift
register and changing the shift register. (7) If data is clocked into the serial
register while LOADDACS is LOW, the selected DAC register will change as
the shift register bits “flow” through A1 and A0. This will corrupt the data in
each DAC register that has been erroneously selected. (8) RESET LOW
causes no change in the contents of the serial shift register.
TABLE III. Serial Shift Register Truth Table.
Note that CS and CLK are combined with an OR gate and
the output controls the serial-to-parallel shift register inter-
nal to the DAC7614 (see the block diagram on the front of
this data sheet). These two inputs are completely inter-
changeable. In addition, care must be taken with the state of
CLK when CS rises at the end of a serial transfer. If CLK is
LOW when CS rises, the OR gate will provide a rising edge
to the shift register, shifting the internal data one additional
bit. The result will be incorrect data and possible selection of
the wrong DAC.
If both CS and CLK are used, then CS should rise only when
CLK is HIGH. If not, then either CS or CLK can be used to
operate the shift register. See Table III for more information.
Digital Input Coding
The DAC7614 input data is in Straight Binary format. The
output voltage is given by the following equation:
where N is the digital input code (in decimal). This equation
does not include the effects of offset (zero-scale) or gain
(full-scale) errors.
(VREFH – VREFL) • N
4096
VOUT = VREFL +
®
12
DAC7614
LAYOUT
A precision analog component requires careful layout, ad-
equate bypassing, and clean, well-regulated power supplies.
As the DAC7614 offers single-supply operation, it will often
be used in close proximity with digital logic, microcontrollers,
microprocessors, and digital signal processors. The more
digital logic present in the design and the higher the switch-
ing speed, the more difficult it will be to achieve good
performance from the converter.
Because the DAC7614 has a single ground pin, all return
currents, including digital and analog return currents, must
flow through the GND pin. Ideally, GND would be con-
nected directly to an analog ground plane. This plane would
be separate from the ground connection for the digital
components until they were connected at the power entry
point of the system (see Figure 4).
The power applied to VDD (as well as VSS, if not grounded)
should be well regulated and low noise. Switching power
supplies and DC/DC converters will often have high-fre-
quency glitches or spikes riding on the output voltage. In
addition, digital components can create similar high-fre-
quency spikes as their internal logic switches states. This
noise can easily couple into the DAC output voltage through
various paths between the power connections and analog
output.
As with the GND connection, VDD should be connected to
a +5V power supply plane or trace that is separate from the
connection for digital logic until they are connected at the
power entry point. In addition, the 1µF to 10µF and 0.1µF
capacitors shown in Figure 4 are strongly recommended. In
some situations, additional bypassing may be required, such
as a 100µF electrolytic capacitor or even a “Pi” filter made
up of inductors and capacitors—all designed to essentially
lowpass filter the +5V supply, removing the high frequency
noise (see Figure 4).
FIGURE 4. Suggested Power and Ground Connections for a DAC7614 Sharing a +5V Supply with a Digital System.
+5V
Power Supply
Optional
Digital Circuits
DAC7614
Other
Analog
Components
+5V
100µF 1µF to
10µF
Ground
+5V
Ground
V
DD
GND
0.1µF
++
