TI DAC8534IPWR Quad channel, low power, 16-bit, serial input digital-to-analog converter Datasheet

DAC8534
DAC
8534
®
SBAS254D – SEPTEMBER 2002 – REVISED MARCH 2004
Quad Channel, Low Power, 16-Bit, Serial Input
DIGITAL-TO-ANALOG CONVERTER
FEATURES
DESCRIPTION
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The DAC8534 is a quad channel, 16-bit Digital-to-Analog
Converter (DAC) offering low-power operation and a flexible
serial host interface. Each on-chip precision output amplifier
allows rail-to-rail output swing to be achieved over the supply
range of 2.7V to 5.5V. The device supports a standard 3-wire
serial interface capable of operating with input data clock
frequencies up to 30MHz for IOVDD = 5V.
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POWER SUPPLY: +2.7V to +5.5V
microPOWER OPERATION: 950µA at 5V
16-BIT MONOTONIC OVER TEMPERATURE
SETTLING TIME: 10µs to ±0.003% FSR
ULTRA-LOW AC CROSSTALK: –100dB typ
POWER-ON RESET TO ZERO-SCALE
ON-CHIP OUTPUT BUFFER AMPLIFIER WITH
RAIL-TO-RAIL OPERATION
DOUBLE BUFFERED INPUT ARCHITECTURE
SIMULTANEOUS OR SEQUENTIAL OUTPUT
UPDATE AND POWER-DOWN
16 CHANNEL BROADCAST CAPABILITY
SCHMITT-TRIGGERED INPUTS
TSSOP-16 PACKAGE
The DAC8534 requires an external reference voltage to set
the output range of each DAC channel. Also incorporated
into the device is a power-on reset circuit which ensures that
the DAC outputs power up at zero-scale and remain there
until a valid write takes place. The DAC8534 provides a per
channel power-down feature, accessed over the serial interface, that reduces the current consumption to 200nA per
channel at 5V.
The low-power consumption of this device in normal operation makes it ideally suited to portable battery-operated
equipment and other low-power applications. The power
consumption is 5mW at 5V, reducing to 4µW in power-down
mode.
APPLICATIONS
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PORTABLE INSTRUMENTATION
CLOSED-LOOP SERVO-CONTROL
PROCESS CONTROL
DATA ACQUISITION SYSTEMS
PROGRAMMABLE ATTENUATION
PC PERIPHERALS
The DAC8534 is available in a TSSOP-16 package with a
specified operating temperature range of –40°C to +105°C.
AVDD
IOVDD
VREFH
Data
Buffer A
DAC
Register A
VOUTA
DAC A
VOUTB
VOUTC
DAC
Register D
Data
Buffer D
VOUTD
DAC D
18
SYNC
SCLK
DIN
24-Bit
Serial-toParallel
Shift
Register
GND
Buffer
Control
Register
Control
Power-Down
Control Logic
Resistor
Network
8
A0
A1
LDAC ENABLE VREFL
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PowerPAD is a trademark of Texas Instruments. All other trademarks are the property of their respective owners.
Copyright © 2002-2004, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
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ELECTROSTATIC
DISCHARGE SENSITIVITY
ABSOLUTE MAXIMUM RATINGS(1)
AVDD to GND ........................................................................ –0.3V to +6V
Digital Input Voltage to GND ............................... –0.3V to +AVDD + 0.3V
VOUTA to VOUTD to GND .................................... –0.3V to + AVDD + 0.3V
Operating Temperature Range ...................................... –40°C to +105°C
Storage Temperature Range ......................................... –65°C to +150°C
Junction Temperature Range (TJ max) ........................................ +150°C
Power Dissipation .......................................................... (TJ max – TA)/θJA
θJA Thermal Impedance ......................................................... 118°C/W
θJC Thermal Impedance ........................................................... 29°C/W
Lead Temperature, Soldering:
Vapor Phase (60s) ............................................................... +215°C
Infrared (15s) ........................................................................ +220°C
This integrated circuit can be damaged by ESD. Texas Instruments 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.
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.
PACKAGE/ORDERING INFORMATION
PRODUCT
DAC8534
PACKAGE-LEAD
PACKAGE
DESIGNATOR(1)
SPECIFICATION
TEMPERATURE
RANGE
PACKAGE
MARKING
ORDERING
NUMBER
TRANSPORT
MEDIA, QUANTITY
TSSOP-16
PW
–40°C to +105°C
D8534I
"
"
"
"
DAC8534IPW
DAC8534IPWR
Tube, 90
Tape and Reel, 2000
"
NOTE: (1) For the most current specifications and package information, refer to our web site at www.ti.com.
ELECTRICAL CHARACTERISTICS
AVDD = +2.7V to +5.5V, –40°C to +105°C, unless otherwise specified.
DAC8534
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
PERFORMANCE (1)
STATIC
Resolution
Relative Accuracy
Differential Nonlinearity
Zero-Scale Error
Zero-Scale Error Drift
Full-Scale Error
Gain Error
Gain Temperature Coefficient
Channel-to-Channel Matching
PSRR
OUTPUT CHARACTERISTICS (2)
Output Voltage Range
Output Voltage Settling Time
Slew Rate
Capacitive Load Stability
Code Change Glitch Impulse
Digital Feedthrough
DC Crosstalk
AC Crosstalk
DC Output Impedance
Short-Circuit Current
Power-Up Time
AC PERFORMANCE
SNR (1st 19 Harmonics Removed)
THD
SFDR
SINAD
16
16-Bit Monotonic
0.25
+5
±7
–0.15
±3
8
0.75
RL = 2kΩ, CL = 200pF
0
To ±0.003% FSR
0200H to FD00H
RL = 2kΩ; 0pF < CL < 200pF
RL = 2kΩ; CL = 500pF
RL = ∞
RL = 2kΩ
1LSB Change Around Major Carry
1kHz sine Wave
AVDD = +5V
AVDD = +3V
Coming Out of Power-Down Mode
AVDD = +5V
Coming Out of Power-Down Mode
AVDD = +3V
BW = 20kHz, AVDD = 5V
FOUT = 1kHz
8
12
1
470
1000
20
0.5
0.25
–100
1
50
20
±0.0987
±1
+20
–1.0
±1.0
VREFH
10
–96
Bits
% of FSR
LSB
mV
µV/°C
% of FSR
% of FSR
ppm of FSR/°C
mV
mV/V
V
µs
µs
V/µs
pF
pF
nV-s
nV-s
LSB
dB
Ω
mA
mA
2.5
µs
5
µs
94
67
69
65
dB
dB
dB
dB
NOTES: (1) Linearity calculated using a reduced code range of 485 to 64714; output unloaded. (2) Ensured by design and characterization, not production tested.
DAC8534
2
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SBAS254D
ELECTRICAL CHARACTERISTICS (Cont.)
AVDD = +2.7V to +5.5V, –40°C to +105°C, unless otherwise specified.
DAC8534
PARAMETER
CONDITIONS
REFERENCE INPUT
Reference Current
MIN
VREF = AVDD = +5V
VREF = AVDD = +3V
Reference Input Range
Reference Input Impedance
TYP
MAX
UNITS
135
80
180
120
AVDD
µA
µA
V
kΩ
±1
0.8
0.6
3
µA
V
V
V
V
pF
5.5
5.5
V
V
0
37
LOGIC INPUTS (2)
Input Current
VINL, Input LOW Voltage
VINL, Input LOW Voltage
VINH, Input HIGH Voltage
VINH, Input HIGH Voltage
Pin Capacitance
IOVDD
IOVDD
IOVDD
IOVDD
POWER REQUIREMENTS
AVDD
IOVDD
AIDD (normal mode)
IOIDD
=
=
=
=
+5V
+3V
+5V
+3V
2.4
2.1
2.7
2.7
DAC Active and Excluding Load Current
AIDD = +3.6V to +5.5V
AIDD = +2.7V to +3.6V
AIDD (all power-down modes)
AIDD = +3.6V to +5.5V
AIDD = +2.7V to +3.6V
10
20
µA
VIH = IOVDD and VIL = GND
VIH = IOVDD and VIL = GND
0.95
0.9
1.6
1.5
mA
mA
VIH = IOVDD and VIL = GND
VIH = IOVDD and VIL = GND
0.8
0.05
1
1
µA
µA
ILOAD = 2mA, AVDD = +5V
89
POWER EFFICIENCY
IOUT/IDD
TEMPERATURE RANGE
Specified Performance
–40
%
+105
°C
NOTES: (1) Linearity calculated using a reduced code range of 485 to 64714; output unloaded. (2) Ensured by design and characterization, not production tested.
PIN CONFIGURATION
PIN DESCRIPTIONS
Top View
TSSOP
VOUTA
1
PIN
NAME
DESCRIPTION
1
VOUTA
Analog output voltage from DAC A.
2
VOUTB
Analog output voltage from DAC B.
2
VREFH
Positive reference voltage input.
4
AVDD
Power supply input, +2.7V to +5.5V.
5
VREFL
Negative reference voltage input.
6
GND
7
VOUTC
8
VOUTD
Analog output voltage from DAC D.
9
SYNC
Level-triggered control input (active LOW). This is
the frame synchronization signal for the input data.
When SYNC goes LOW, it enables the input shift
register and data is transferred in on the falling
edges of the following clocks. The DAC is updated
following the 24th clock (unless SYNC is taken
HIGH before this edge in which case the rising edge
of SYNC acts as an interrupt and the write sequence
is ignored by the DAC8534).
10
SCLK
Serial Clock Input. Data can be transferred at rates
up to 30MHz.
11
DIN
Serial Data Input. Data is clocked into the 24-bit
input shift register on each falling edge of the serial
clock input.
12
13
14
15
IOVDD
A0
A1
ENABLE
16
LDAC
Digital Input-Output Power Supply
Address 0 — sets device address, see Table II.
Address 1 — sets device address, see Table II.
Active LOW, ENABLE LOW connects the SPI interface to the serial port.
Load DACs, rising edge triggered loads all DAC
registers.
16 LDAC
VOUTB
2
15 ENABLE
VREFH
3
14 A1
AVDD
4
13 A0
VREFL
5
12 IOVDD
GND
6
11 DIN
VOUTC
7
10 SCLK
VOUTD
8
9
DAC8534
SYNC
DAC8534
SBAS254D
Ground reference point for all circuitry on the part.
Analog output voltage from DAC C.
3
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TIMING CHARACTERISTICS(1, 2)
AVDD = +2.7V to +5.5V; all specifications –40°C to +105°C unless otherwise noted.
DAC8534
PARAMETER
DESCRIPTION
CONDITIONS
MIN
SCLK Cycle Time
IOVDD = AVDD = 2.7V to 3.6V
IOVDD = AVDD = 3.6V to 5.5V
50
33
ns
ns
t2
SCLK HIGH Time
IOVDD = AVDD = 2.7V to 3.6V
IOVDD = AVDD = 3.6V to 5.5V
26
15
ns
ns
t3
SCLK LOW Time
IOVDD = AVDD = 2.7V to 3.6V
IOVDD = AVDD = 3.6V to 5.5V
22.5
13
ns
ns
t4
SYNC Falling Edge to SCLK
Rising Edge Setup Time
IOVDD = AVDD = 2.7V to 3.6V
IOVDD = AVDD = 3.6V to 5.5V
0
0
ns
ns
t5
Data Setup Time
IOVDD = AVDD = 2.7V to 3.6V
IOVDD = AVDD = 3.6V to 5.5V
5
5
ns
ns
t6
Data Hold Time
IOVDD = AVDD = 2.7V to 3.6V
IOVDD = AVDD = 3.6V to 5.5V
4.5
4.5
ns
ns
t7
24th SCLK Falling Edge to
SYNC Rising Edge
IOVDD = AVDD = 2.7V to 3.6V
IOVDD = AVDD = 3.6V to 5.5V
0
0
ns
ns
t8
Minimum SYNC HIGH Time
IOVDD = AVDD = 2.7V to 3.6V
IOVDD = AVDD = 3.6V to 5.5V
50
33
ns
ns
t9
24th SCLK Falling Edge to
SYNC Falling Edge
IOVDD = AVDD = 2.7V to 5.5V
130
ns
t1
(3)
TYP
MAX
UNITS
NOTES: (1) All input signals are specified with tR = tF = 3ns (10% to 90% of AVDD) and timed from a voltage level of (VIL + VIH)/2. (2) See Serial Write Operation
timing diagram, below. (3) Maximum SCLK frequency is 30MHz at IOVDD = AVDD = +3.6V to +5.5V and 20MHz at IOVDD = AVDD = +2.7V to +3.6V.
SERIAL WRITE OPERATION
t1
SCLK
t9
1
24
t8
t3
t4
t2
t7
SYNC
t6
t5
DIN
DB23
DB0
DB23
DAC8534
4
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SBAS254D
TYPICAL CHARACTERISTICS
At TA = +25°C, unless otherwise noted.
64
48
32
16
0
–16
–32
–48
–64
CHANNEL A
LINEARITY ERROR AND DIFFERENTIAL
LINEARITY ERROR vs DIGITAL INPUT CODE
AVDD = 5V
LE (LSB)
LE (LSB)
LINEARITY ERROR AND DIFFERENTIAL
LINEARITY ERROR vs DIGITAL INPUT CODE
0.5
0.0
–0.5
LINEARITY ERROR AND DIFFERENTIAL
LINEARITY ERROR vs DIGITAL INPUT CODE
LINEARITY ERROR AND DIFFERENTIAL
LINEARITY ERROR vs DIGITAL INPUT CODE
CHANNEL C
AVDD = 5V
64
48
32
16
0
–16
–32
–48
–64
CHANNEL D
AVDD = 5V
1.0
DLE (LSB)
DLE (LSB)
0.5
0.0
–0.5
0.0
–0.5
Digital Input Code
Digital Input Code
LINEARITY ERROR AND DIFFERENTIAL
LINEARITY ERROR vs DIGITAL INPUT CODE
LINEARITY ERROR AND DIFFERENTIAL
LINEARITY ERROR vs DIGITAL INPUT CODE
CHANNEL A
AVDD = 2.7V
64
48
32
16
0
–16
–32
–48
–64
CHANNEL B
AVDD = 2.7V
1.0
DLE (LSB)
1.0
0.5
0.0
–0.5
–1.0
0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH
Digital Input Code
0.5
0.0
–0.5
–1.0
0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH
Digital Input Code
DAC8534
SBAS254D
0.5
–1.0
0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH
LE (LSB)
LE (LSB)
0.0
–0.5
Digital Input Code
–1.0
0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH
DLE (LSB)
0.5
Digital Input Code
1.0
64
48
32
16
0
–16
–32
–48
–64
AVDD = 5V
–1.0
0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH
LE (LSB)
LE (LSB)
–1.0
0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH
64
48
32
16
0
–16
–32
–48
–64
CHANNEL B
1.0
DLE (LSB)
DLE (LSB)
1.0
64
48
32
16
0
–16
–32
–48
–64
5
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TYPICAL CHARACTERISTICS (Cont.)
At TA = +25°C, unless otherwise noted.
LINEARITY ERROR AND DIFFERENTIAL
LINEARITY ERROR vs DIGITAL INPUT CODE
CHANNEL C
64
48
32
16
0
–16
–32
–48
–64
AVDD = 2.7V
LE (LSB)
LE (LSB)
64
48
32
16
0
–16
–32
–48
–64
LINEARITY ERROR AND DIFFERENTIAL
LINEARITY ERROR vs DIGITAL INPUT CODE
AVDD = 2.7V
1.0
0.5
DLE (LSB)
DLE (LSB)
1.0
CHANNEL D
0.0
–0.5
0.5
0.0
–0.5
–1.0
0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH
–1.0
0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH
Digital Input Code
Digital Input Code
ZERO-SCALE ERROR vs TEMPERATURE
ZERO-SCALE ERROR vs TEMPERATURE
10
10
CH D
AVDD = VREF = 5V
CH C
AVDD = VREF = 2.7V
8
8
Error (mV)
Error (mV)
6
6
4
CH A
CH C
CH B
CH D
4
2
2
0
CH B
0
–40
CH A
–10
20
50
80
–2
–40
110
–10
20
110
20
CH C
15
15
CH D
CH C
CH D
To avoid clipping of the output signal
during the test, VREF = AVDD – 10mV,
AVDD = 2.7V, VREF = 2.69V
10
To avoid clipping of the output signal
during the test, VREF = AVDD – 10mV,
AVDD = 5V, VREF = 4.99V
Error (mV)
10
Error (mV)
80
FULL-SCALE ERROR vs TEMPERATURE
FULL-SCALE ERROR vs TEMPERATURE
20
5
50
Temperature (°C)
Temperature (°C)
CH B
5
0
0
–5
–5
CH A
CH B
CH A
–10
–40
–10
20
50
80
–10
–40
110
–10
20
50
80
110
Temperature (°C)
Temperature (°C)
DAC8534
6
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SBAS254D
TYPICAL CHARACTERISTICS (Cont.)
At TA = +25°C, unless otherwise noted.
SINK CURRENT CAPABILITY (ALL CHANNELS)
0.150
SOURCE CURRENT CAPABILITY (ALL CHANNELS)
5.00
VREF = AVDD – 10mV
DAC loaded with 0000H
0.125
VREF = AVDD – 10mV
DAC Loaded with FFFFH
AVDD = 5V
4.95
VOUT (V)
VOUT (V)
0.100
0.075
AVDD = 5V
4.90
0.050
4.85
0.025
AVDD = 2.7V
0.000
4.80
0
1
2
3
4
0
5
1
2
3
4
5
ISOURCE (mA)
ISINK (mA)
SUPPLY CURRENT vs DIGITAL INPUT CODE
SOURCE CURRENT CAPABILITY (ALL CHANNELS)
2.70
1200
VREF = AVDD – 10mV
DAC Loaded with FFFFH
AVDD = 2.7V
2.65
AVDD = VREF = 5V
1000
AIDD (µA)
VOUT (V)
800
2.60
600
AVDD = VREF = 2.7V
400
2.55
200
0
0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH
2.50
0
1
2
3
4
5
ISOURCE (mA)
Digital Input Code
SUPPLY CURRENT vs TEMPERATURE
SUPPLY CURRENT vs SUPPLY VOLTAGE
1000
1200
AVDD = VREF = 5V
950
1000
900
AIDD (µA)
AIDD (µA)
800
AVDD = VREF = 2.7V
600
400
Reference Current Included
All Channels Powered, No Load.
850
800
750
700
200
650
600
0
–40
–10
20
50
80
2.7
110
Temperature (°C)
DAC8534
SBAS254D
3.05
3.4
3.75
4.1
4.45
AVDD (V)
4.8
5.15
5.5
7
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TYPICAL CHARACTERISTICS (Cont.)
At TA = +25°C, unless otherwise noted.
SUPPLY CURRENT vs LOGIC INPUT VOLTAGE
HISTOGRAM OF CURRENT CONSUMPTION
1750
1500
TA = 25°C, SYNC Input (All others inputs = GND)
Reference Current Included
1650
AVDD = VREF = 5V
Reference Current Included
1450
1000
AVDD = VREF = 5V
1350
Frequency
AIDD + IOIDD (µA)
1550
1250
1150
500
1050
AVDD = VREF = 2.7V
950
850
750
1150
1120
VLOGIC (V)
1090
5.0
1060
4.5
1030
4.0
1000
3.5
970
3.0
940
2.5
910
2.0
880
1.5
850
1.0
790
0.5
820
0
0
AIDD (µA)
HISTOGRAM OF CURRENT CONSUMPTION
1500
5.5
AVDD = VREF = 2.7V
Reference Current Included
5.0
4.5
EXITING POWER-DOWN MODE
AVDD = VREF = 5V
Power-Up Code = FFFFH
4.0
Frequency
VOUT (V)
1000
3.5
3.0
2.5
2.0
1.5
500
1.0
0.5
0.0
–0.5
Time (3µs/div)
1060
1030
1000
970
940
910
880
850
820
790
760
730
0
AIDD (µA)
OUTPUT GLITCH
(Worst Case)
OUTPUT GLITCH
(Mid-Scale)
2.52
VOUT (V, 10mV/div)
2.51
2.50
AVDD = VREF = 5V
Code 7FFFH to 8000H to 7FFFH
(Glitch Occurs Every N • 4096
Code Boundary)
2.49
2.48
2.47
2.46
4.72
4.70
4.68
VOUT (V, 20mV/div)
2.53
AVDD = VREF = 5V
Code EFFFH to F000H to EFFFH
(Glitch Occurs Every N • 4096
Code Boundary)
4.66
4.64
4.62
4.60
4.58
2.45
4.56
2.44
4.54
2.43
Time (1µs/div)
Time (1µs/div)
DAC8534
8
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SBAS254D
TYPICAL CHARACTERISTICS (Cont.)
At TA = +25°C, unless otherwise noted.
ABSOLUTE ERROR
20
AVDD = VREF = 5V
TA = 25°C
16
Output Error (mV)
14
6
Channel D Output
Channel B Output
12
10
8
6
4
Channel B Output
Channel D Output
2
0
–2
–4
Channel A Output
–8
Channel C Output
–10
0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH
Channel C Output
0
0000H 2000H 4000H 6000H 8000H A000H C000H E000H FFFFH
Digital Input Code
Digital Input Code
FULL-SCALE SETTLING TIME
(Large Signal)
HALF-SCALE SETTLING TIME
(Large Signal)
6
3.0
AVDD = VREF = 5.5V
Output Loaded with
2kΩ and 200pF
to GND
5
AVDD = VREF = 5V
Output Loaded with
2kΩ and 200pF
to GND
2.5
2.0
VOUT (V)
4
VOUT (V)
4
–6
Channel A Output
2
3
1.5
2
1.0
1
0.5
0
0
Time (12µs/div)
Time (12µs/div)
FULL-SCALE SETTLING TIME
(Large Signal)
HALF-SCALE SETTLING TIME
3.5
AVDD = VREF = 2.7V
Output Loaded with
2kΩ and 200pF
to GND
3.0
1.5
VOUT (V)
2.5
VOUT (V)
AVDD = VREF = 2.7V
TA = 25°C
8
Output Error (mV)
18
ABSOLUTE ERROR
10
2.0
1.5
1.0
1.0
0.5
AVDD = VREF = 2.7V
Output Loaded with
2kΩ and 200pF
to GND
0.5
0
0
Time (12µs/div)
Time (12µs/div)
DAC8534
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TYPICAL CHARACTERISTICS (Cont.)
At TA = +25°C, unless otherwise noted.
SIGNAL-TO-NOISE RATIO vs OUTPUT FREQUENCY
98
0
AVDD = VREF = 5V
FS = 52ksps, –1dB FSR Digital Input
Measurement Bandwidth = 20kHz
–10
96
–20
AVDD = 5V
94
–30
THD (dB)
SNR (dB)
TOTAL HARMONIC DISTORTION vs
OUTPUT FREQUENCY
92
AVDD = 2.7V
90
–40
THD
–50
–60
–70
88
AVDD = VREF
–1dB FSR Digital Input, FS = 52ksps
Measurement Bandwidth = 20kHz
86
–80
3rd-Harmonic
–90
84
2nd-Harmonic
–100
0
500
1.0k
1.5k
2.0k
2.5k
3.0k
3.5k
4.0k
4.5k
0
500
1.0k
Output Frequency (Hz)
4.0k
AVDD = VREF = 2.7V
FS = 52ksps, –1dB FSR Digital Input
Measurement Bandwidth = 20kHz
–10
–20
Output Voltage
–30
THD (dB)
3.5k
FULL-SCALE SETTLING TIME
(Small-Signal-Positive Going Step)
TOTAL HARMONIC DISTORTION vs
OUTPUT FREQUENCY
0
1.5k 2.0k 2.5k 3.0k
Output Frequency (Hz)
–40
THD
–50
–60
–70
Small-Signal Settling Time
5mV/div
–80
Trigger Pulse
–90
2nd-Harmonic
3rd-Harmonic
–100
0
500
1.0k
1.5k 2.0k 2.5k 3.0k
Output Frequency (Hz)
3.5k
4.0k
Time (2µs/div)
Output Voltage
FULL-SCALE SETTLING TIME
(Small-Signal-Negative Going Step)
Small-Signal Settling Time
5mV/div
Trigger Pulse
Time (2µs/div)
DAC8534
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SBAS254D
THEORY OF OPERATION
VREFH
DAC SECTION
RDIVIDER
The architecture of each channel of the DAC8534 consists of
a resistor-string DAC followed by an output buffer amplifier.
Figure 1 shows a simplified block diagram of the DAC
architecture.
VREFH
50kΩ
VREF
2
R
R
50kΩ
To Output
Amplifier
(2x Gain)
70kΩ
DAC Register
VOUT
REF (+)
Resistor String
REF(–)
VREFL
R
FIGURE 1. DAC8534 Architecture.
R
The input coding for each device is unipolar straight binary,
so the ideal output voltage is given by:
VOUT X = 2 • VREFL + (VREF H − VREF L) •
VREFL
DIN
65536
FIGURE 2. Resistor String.
where D = decimal equivalent of the binary code that is
loaded to the DAC register; it can range from 0 to 65535.
VOUTX refers to channel A or through D.
RESISTOR STRING
The resistor string section is shown in Figure 2. It is simply
a divide-by-2 resistor followed by a string of resistors. The
code loaded into the DAC register determines at which node
on the string the voltage is tapped off. This voltage is then
applied to the output amplifier by closing one of the switches
connecting the string to the amplifier.
OUTPUT AMPLIFIER
Each output buffer amplifier is capable of generating rail-torail voltages on its output which approaches an output range
of 0V to AVDD (gain and offset errors must be taken into
account). Each buffer is capable of driving a load of 2kΩ in
parallel with 1000pF to GND. The source and sink capabilities of the output amplifier can be seen in the typical characteristics.
SERIAL INTERFACE
The DAC8534 uses a 3-wire serial interface (SYNC, SCLK,
and DIN), which is compatible with SPI™, QSPI™, and
Microwire™ interface standards, as well as most DSPs. See
the Serial Write Operation timing diagram for an example of
a typical write sequence.
The write sequence begins by bringing the SYNC line LOW.
Data from the DIN line is clocked into the 24-bit shift register on
each falling edge of SCLK. The serial clock frequency can be
as high as 30MHz, making the DAC8534 compatible with highspeed DSPs. On the 24th falling edge of the serial clock, the
last data bit is clocked into the shift register and the shift
register gets locked. Further clocking does not change the shift
register data. Once 24 bits are locked into the shift register, the
8MSBs are used as control bits and the 16LSBs are used as
data. After receiving the 24th falling clock edge, DAC8534
decodes the 8 control bits and 16 data bits to perform the
required function, without waiting for a SYNC rising edge. A
new SPI sequence starts at the next falling edge of SYNC. A
rising edge of SYNC before the 24-bit sequence is complete
resets the SPI interface; no data transfer occurs.
At this point, the SYNC line may be kept LOW or brought HIGH.
In either case, the minimum delay time from the 24th falling
SCLK edge to the next falling SYNC edge must be met in order
to properly begin the next cycle. To assure the lowest power
consumption of the device, care should be taken that the digital
input levels are as close to each rail as possible. (Please refer
to the “Typical Characteristics” section for the “Supply Current
vs Logic Input Voltage” transfer characteristic curve.)
IOVDD AND VOLTAGE TRANSLATORS
The IOVDD pin powers the digital input structures of the
DAC8534. For single-supply operation, it could be tied to AVDD.
For dual-supply operation, the IOVDD pin provides interface
flexibility with various CMOS logic families and it should be
connected to the logic supply of the system. Analog circuits and
internal logic of the DAC8534 use AVDD as the supply voltage.
The external logic high inputs get translated to AVDD by level
shifters. These level shifters use the IOVDD voltage as a
DAC8534
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reference to shift the incoming logic HIGH levels to AVDD.
IOVDD is ensured to operate from 2.7V to 5.5V regardless of
the AVDD voltage, which ensures compatibility with various
logic families. Although specified down to 2.7V, IOVDD will
operate at as low as 1.8V with degraded timing and temperature performance. For lowest power consumption, logic VIH
levels should be as close as possible to IOVDD, and logic VIL
levels should be as close as possible to GND voltages.
INPUT SHIFT REGISTER
The input shift register (SR) of the DAC8534 is 24 bits wide, as
shown in Figure 3, and is made up of 8 control bits (DB16-DB23)
and 16 data bits (DB0-DB15). The first two control bits (DB22
and DB23) are the address match bits. The DAC8534 offers
additional hardware-enabled addressing capability allowing a
single host to talk to up to four DAC8534s through a single SPI
bus without any glue logic, enabling up to 16-channel operation.
The state of DB23 should match the state of pin A1; similarly, the
state of DB22 should match the state of pin A0. If there is no
match, the control command and the data (DB21...DB0) are
ignored by the DAC8534. That is, if there is no match, the
DAC8534 is not addressed. Address matching can be overridden by the broadcast update, as will be explained.
DAC8534s get updated with previously stored data (or powerdown). If DB18 = 1, then SR data (or power-down) updates all
channels of all DAC8534s in the system. This broadcast update
feature allows the simultaneous update of up to 16 channels.
Power-down/data selection is as follows:
DB16 is a power-down flag. If this flag is set, then DB15 and
DB14 select one of the four power-down modes of the device
as described in Table I. If DB16 = 1, DB15 and DB14 no longer
represent the two MSBs of data, they represent a power-down
condition described in Table I. Similar to data, power-down
conditions can be stored at the temporary registers of each
DAC. It is possible to update DACs simultaneously either with
data, power-down, or a combination of both.
Please refer to Table II for more information.
PD0 (DB16) PD1 (DB15) PD2 (DB14)
OPERATING MODE
1
0
0
Output High Impedance
1
0
1
Output Typically 1kΩ to GND
1
1
0
Output Typically 100kΩ to GND
1
1
1
Output High Impedance
TABLE I. DAC8534 Power-Down Modes.
SYNC INTERRUPT
LD 1 (DB20) and LD 0 (DB21) control the updating of each
analog output with the specified 16-bit data value or powerdown command. Bit DB19 is a “Don’t Care” bit which does not
affect the operation of the DAC8534 and can be 1 or 0. The
DAC Channel Select Bits (DB17, DB18) control the destination
of the data (or power-down command) from DAC A through
DAC D. The final control bit, PD0 (DB16), selects the powerdown mode of the DAC8534 channels.
In a normal write sequence, the SYNC line is kept LOW for
at least 24 falling edges of SCLK and the addressed DAC
register is updated on the 24th falling edge. However, if
SYNC is brought HIGH before the 24th falling edge, it acts
as an interrupt to the write sequence; the shift register is
reset and the write sequence is discarded. Neither an update
of the data buffer contents, DAC register contents, nor a
change in the operating mode occurs (see Figure 4).
The DAC8534 also supports a number of different load commands. The load commands include broadcast commands to
address all the DAC8534s on an SPI bus. The load commands
can be summarized as follows:
POWER-ON RESET
DB21 = 0 and DB20 = 0: Single-channel store. The temporary
register (data buffer) corresponding to a DAC selected by
DB18 and DB17 is updated with the contents of SR data (or
power-down).
DB21 = 0 and DB20 = 1: Single-channel update. The temporary register and DAC register corresponding to a DAC selected by DB18 and DB17 are updated with the contents of SR
data (or power-down).
DB21 = 1 and DB20 = 0: Simultaneous update. A channel
selected by DB18 and DB17 gets updated with the SR data,
and simultaneously, all the other channels get updated with
previous stored data (or power-down).
DB21 = 1 and DB20 = 1: Broadcast update. All the DAC8534s
on the SPI bus respond, regardless of address matching. If
DB18 = 0, then SR data gets ignored, all channels from all
The DAC8534 contains a power-on reset circuit that controls the output voltage during power-up. On power-up, the
DAC registers are filled with zeros and the output voltages
are set to zero-scale; they remain there until a valid write
sequence and load command is made to the respective
DAC channel. This is useful in applications where it is
important to know the state of the output of each DAC
output while the device is in the process of powering up. No
device pin should be brought high before power is applied
to the device.
POWER-DOWN MODES
The DAC8534 utilizes four modes of operation. These modes
are accessed by setting three bits (PD2, PD1, and PD0) in
the shift register and performing a “Load” action to the DACs.
The DAC8534 offers a very flexible power-down interface
based on channel register operation. A channel consists of a
DB23
A1
DB12
A0
LD1
LD0
X
D10
D9
D8
D7
DAC Select 1 DAC Select 0
PD0
D15
D14
D13
D12
D4
D3
D2
D1
D0
DB11
D11
DB0
D6
D5
FIGURE 3. DAC8534 Data Input Register Format.
DAC8534
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SBAS254D
D23
D22
D21
D20
A1
A0
Load 1
Load 0
D19
D18
D17
Don’t Care DAC Sel 1 DAC Sel 0
D16
D15
D14
D13-D0
PD0
MSB
MSB-1
MSB-2...LSB
DESCRIPTION
(Address Select)
0/1
(A0 and A1 should
correspond to the
package address set
via pins 13 and 14.)
This address selects 1 of 4 possible devices on a single SPI
data bus based on each device’s address pin(s) state.
See Below
0/1
0
0
X
0
0
0
Data
Write To Buffer A w/Data
0
0
X
0
1
0
Data
Write To Buffer B w/Data
0
0
X
1
0
0
Data
Write To Buffer C w/Data
0
0
X
1
1
0
Data
0
0
X
(00, 01, 10, or 11)
1
0
1
X
(00, 01, 10, or 11)
0
0
1
X
(00, 01, 10, or 11)
1
1
0
X
(00, 01, 10, or 11)
0
1
0
X
(00, 01, 10, or 11)
1
Write To Buffer D w/Data
0
(see Table I)
Write To Buffer (selected by DB17 and DB18) w/Power-Down
Command
Write To Buffer w/Data and Load DAC (selected by DB17 and
DB18)
Data
(see Table I)
0
Write To Buffer w/Power-Down Command and Load DAC
(selected by DB17 and DB18)
Write To Buffer w/Data (selected by DB17 and DB18) and Load All
DACs
Data
0
(see Table I)
Write To Buffer w/Power-Down Command (selected by DB17 and
DB18) and Load All DACs
Broadcast Modes
X
X
1
1
X
0
X
X
X
X
X
1
1
X
1
X
0
Data
X
X
1
1
X
1
X
1
Load All DACs, All Device, and All Buffers with Stored Data
Write To All Devices and Load All Dacs, with SR Data
(see Table I)
0
Write To All Devices w/Power-Down Command in SR
TABLE II. Control Matrix.
24th Falling
Edge
SCLK
1
2
1
24th Falling
Edge
2
SYNC
Invalid Write-Sync Interrupt:
SYNC HIGH Before 24th Falling Edge
DIN
DB23 DB22
Valid Write-Buffer/DAC Update:
SYNC HIGH After 24th Falling Edge
DB0
DB23 DB22
DB1
DB0
FIGURE 4. Interrupt and Valid SYNC Timing.
single 16-bit DAC with power-down circuitry, a temporary
storage register (TR), and a DAC register (DR). TR and DR
are both 18-bit wide. Two MSBs represent power-down
condition and 16LSBs represent data for TR and DR. By
adding bits 17 and 18 to TR and DR, a power-down condition
can be temporarily stored and used just like data. Internal
circuits ensure that DB15 and DB14 get transfered to TR17
and TR16 (DR17 and DR16), when DB16 = 1.
The DAC8534 treats the power-down condition like data and
all the operational modes are still valid for power-down. It is
possible to broadcast a power-down condition to all the
DAC8534s in a system, or it is possible to simultaneously
power-down a channel while updating data on other channels.
DB16, DB15, and DB14 = 100 represent a power-down
condition with Hi-Z output impedance for a selected channel.
Same is true for 111. 101 represents a power-down condition
with 1k output impedance and 110 represents a power-down
condition with 100k output impedance.
When both bits are set to 0 or 1, the device enters a highimpedance state with a typical power consumption of 3pA at
5V. For the two low impedance output modes, however, the
supply current falls to 100nA at 5V (50nA at 3V). Not only does
the supply current fall, but the output stage is also internally
switched from the output of the amplifier to a resistor network
of known values. This has the advantage that the output
impedance of the device is known while it is in power-down
mode. There are three different options for power-down: the
output is connected internally to GND through a 1kΩ resistor,
a 100kΩ resistor, or it is left open-circuited (High-Impedance).
The output stage is illustrated in Figure 5.
All analog circuitry is shut down when the power-down mode
is activated. Each DAC will exit power-down when PD0 is set
to 0, new data is written to the Data Buffer, and the DAC
channel receives a “Load” command. The time to exit powerdown is typically 2.5µs for AVDD = 5V and 5µs for AVDD = 3V
(see the Typical Characteristics).
DAC8534
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Resistor
String DAC
Amplifier
VOUTX
Power-down
Circuitry
Resistor
Network
FIGURE 5. Output Stage During Power-Down (High-Impedance).
OPERATION EXAMPLES
Example 1: Write to Data Buffer A; Through Buffer D; Load DAC A Through DAC D Simultaneously
• 1st—Write to Data Buffer A:
A1
A0
LD1
LD0
DC
DAC Sel 1
DAC Sel 0
PD0
DB15
......
DB1
DB0
0
0
0
0
X
0
0
0
D15
.....
D1
D0
• 2nd—Write to Data Buffer B:
A1
A0
LD1
LD0
DC
DAC Sel 1
DAC Sel 0
PD0
DB15
......
DB1
DB0
0
0
0
0
X
0
1
0
D15
.....
D1
D0
• 3rd—Write to Data Buffer C:
A1
A0
LD1
LD0
DC
DAC Sel 1
DAC Sel 0
PD0
DB15
......
DB1
DB0
0
0
0
0
X
1
0
0
D15
.....
D1
D0
• 4th—Write to Data Buffer D and simultaneously update all DACs:
A1
A0
LD1
LD0
DC
DAC Sel 1
DAC Sel 0
PD0
DB15
......
DB1
DB0
0
0
1
0
X
1
1
0
D15
.....
D1
D0
The DAC A, DAC B, DAC C, and DAC D analog outputs simultaneously settle to the specified values upon completion of the
4th write sequence. (The “Load” command moves the digital data from the data buffer to the DAC register at which time the
conversion takes place and the analog output is updated. “Completion” occurs on the 24th falling SCLK edge after SYNC LOW.)
Example 2: Load New Data to DAC A Through DAC D Sequentially
• 1st—Write to Data Buffer A and Load DAC A: DAC A output settles to specified value upon completion:
A1
A0
LD1
LD0
DC
DAC Sel 1
DAC Sel 0
PD0
DB15
......
DB1
DB0
0
0
0
1
X
0
0
0
D15
.....
D1
D0
• 2nd—Write to Data Buffer B and Load DAC B: DAC B output settles to specified value upon completion:
A1
A0
LD1
LD0
DC
DAC Sel 1
DAC Sel 0
PD0
DB15
......
DB1
DB0
0
0
0
1
X
0
1
0
D15
.....
D1
D0
• 3rd—Write to Data Buffer C and Load DAC C: DAC C output settles to specified value upon completion:
A1
A0
LD1
LD0
DC
DAC Sel 1
DAC Sel 0
PD0
DB15
......
DB1
DB0
0
0
0
1
X
1
0
0
D15
.....
D1
D0
• 4th—Write to Data Buffer D and Load DAC D: DAC D output settles to specified value upon completion:
A1
A0
LD1
LD0
DC
DAC Sel 1
DAC Sel 0
PD0
DB15
......
DB1
DB0
0
0
0
1
X
1
1
0
D15
.....
D1
D0
After completion of each write cycle, DAC analog output settles to the voltage specified.
Example 3: Power-Down DAC A and DAC B to 1kΩ and Power-Down DAC C and DAC D to 100kΩ Simultaneously
• Write power-down command to Data Buffer A: DAC A to 1kΩ.
A1
A0
LD1
LD0
DC
DAC Sel 1
DAC Sel 0
PD0
DB15
DB14
DB13
........
0
0
0
0
X
0
0
1
0
1
X
........
DAC8534
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SBAS254D
• Write power-down command to Data Buffer B: DAC B to 1kΩ.
A1
A0
LD1
LD0
DC
DAC Sel 1
DAC Sel 0
PD0
DB15
DB14
DB13
........
0
0
0
0
X
0
1
1
0
1
X
........
• Write power-down command to Data Buffer C: DAC C to 100kΩ.
A1
A0
LD1
LD0
DC
DAC Sel 1
DAC Sel 0
PD0
DB15
DB14
DB13
........
0
0
0
0
X
1
0
1
1
0
X
........
• Write power-down command to Data Buffer D: DAC D to 100kΩ and Simultaneously Update all DACs.
A1
A0
LD1
LD0
DC
DAC Sel 1
DAC Sel 0
PD0
DB15
DB14
DB13
........
0
0
1
0
X
1
1
1
1
0
X
........
The DAC A, DAC B, DAC C, and DAC D analog outputs simultaneously power-down to each respective specified mode upon
completion of the 4th write sequence.
Example 4: Power-Down DAC A Through DAC D to High-Impedance Sequentially:
• Write power-down command to Data Buffer A and Load DAC A: DAC A output = High-Z:
A1
A0
LD1
LD0
DC
DAC Sel 1
DAC Sel 0
PD0
DB15
DB14
DB13
........
0
0
0
1
X
0
0
1
1
1
X
........
• Write power-down command to Data Buffer B and Load DAC B: DAC B output = High-Z:
A1
A0
LD1
LD0
DC
DAC Sel 1
DAC Sel 0
PD0
DB15
DB14
DB13
........
0
0
0
1
X
0
1
1
1
1
X
........
• Write power-down command to Data Buffer C and Load DAC C: DAC C output = High-Z:
A1
A0
LD1
LD0
DC
DAC Sel 1
DAC Sel 0
PD0
DB15
DB14
DB13
........
0
0
0
1
X
1
0
1
1
1
X
........
• Write power-down command to Data Buffer D and Load DAC D: DAC D output = High-Z:
A1
A0
LD1
LD0
DC
DAC Sel 1
DAC Sel 0
PD0
DB15
DB14
DB13
........
0
0
0
1
X
1
1
1
1
1
X
........
The DAC A, DAC B, DAC C, and DAC D analog outputs sequentially power-down to high-impedance upon completion of the
1st, 2nd, 3rd, and 4th write sequences, respectively.
LDAC FUNCTIONALITY
The DAC8534 offers both a software and hardware simultaneous update function. The DAC8534 double-buffered architecture has been designed so that new data can be entered for
each DAC without disturbing the analog outputs. The software
simultaneous update capability is controlled by the Load 1 (LD1)
and Load 0 (LD0) control bits. By setting Load 1 equal to “1” all
of the DAC registers will be updated on the falling edge of the
24th clock signal. When the new data has been entered into the
device, all of the DAC outputs can be updated simultaneously
and synchronously with the clock.
The internal DAC register is edge triggered and not level
triggered, therefore, when the LDAC pin signal is transitioned
from LOW to HIGH, the digital word currently in the DAC input
register is latched. Additionally, it allows the DAC input registers
to be written to at any point; then, the DAC output voltages can
be asynchronously changed via the LDAC pin. The LDAC trigger
should only be used after the buffers are properly updated
through software. If DAC outputs are desired to be updated
through software only, the LDAC pin must be tied low permanently.
MICROPROCESSOR
INTERFACING
DAC8534 to 8051 INTERFACE
See Figure 6 for a serial interface between the DAC8534 and
a typical 8051-type microcontroller. The setup for the interface is as follows: TXD of the 8051 drives SCLK of the
DAC8534, while RXD drives the serial data line of the device.
The SYNC signal is derived from a bit-programmable pin on
the port of the 8051. In this case, port line P3.3 is used. When
data is to be transmitted to the DAC8534, P3.3 is taken LOW.
The 8051 transmits data in 8-bit bytes; thus only eight falling
clock edges occur in the transmit cycle. To load data to the
DAC, P3.3 is left LOW after the first eight bits are transmitted,
then a second and third write cycle is initiated to transmit the
remaining data. P3.3 is taken HIGH following the completion
of the third write cycle. The 8051 outputs the serial data in a
format which presents the LSB first, while the DAC8534
requires its data with the MSB as the first bit received. The
8051 transmit routine must therefore take this into account,
and “mirror” the data as needed.
DAC8534
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DAC8534 to TMS320 DSP INTERFACE
80C51/80L51(1)
DAC8534(1)
P3.3
SYNC
TXD
SCLK
RXD
DIN
Figure 9 shows the connections between the DAC8534 and
a TMS320 Digital Signal Processor (DSP). A Single DSP can
control up to four DAC8534s without any interface logic.
DAC8534
NOTE: (1) Additional pins omitted for clarity.
Positive Supply
AVDD
FIGURE 6. DAC8534 to 80C51/80L51 Interface.
0.1µF
10µF
TMS320 DSP
DAC8534 to Microwire INTERFACE
FSX
Figure 7 shows an interface between the DAC8534 and any
Microwire compatible device. Serial data is shifted out on the
falling edge of the serial clock and is clocked into the
DAC8534 on the rising edge of the CK signal.
DX
CLKX
SYNC
DIN
SCLK
VOUTA
Output A
VOUTD
Output D
Reference
Input
VREFH
VREFL
0.1µF
1µF to 10µF
GND
MicrowireTM
DAC8534(1)
CS
SYNC
SK
SCLK
SO
DIN
FIGURE 9. DAC8534 to TMS320 DSP.
APPLICATIONS
CURRENT CONSUMPTION
NOTE: (1) Additional pins omitted for clarity.
Microwire is a registered trademark of National Semiconductor.
FIGURE 7. DAC8534 to Microwire Interface.
DAC8534 to 68HC11 INTERFACE
Figure 8 shows a serial interface between the DAC8534 and
the 68HC11 microcontroller. SCK of the 68HC11 drives the
SCLK of the DAC8534, while the MOSI output drives the
serial data line of the DAC. The SYNC signal is derived from
a port line (PC7), similar to the 8051 diagram.
68HC11(1)
DAC8534(1)
PC7
SYNC
SCK
SCLK
MOSI
DIN
NOTE: (1) Additional pins omitted for clarity.
FIGURE 8. DAC8534 to 68HC11 Interface.
The 68HC11 should be configured so that its CPOL bit is 0
and its CPHA bit is 1. This configuration causes data appearing on the MOSI output to be valid on the falling edge of
SCLK. When data is being transmitted to the DAC, the
SYNC line is held LOW (PC7). Serial data from the 68HC11
is transmitted in 8-bit bytes with only eight falling clock edges
occurring in the transmit cycle. (Data is transmitted MSB
first.) In order to load data to the DAC8534, PC7 is left LOW
after the first eight bits are transferred, then a second and
third serial write operation is performed to the DAC. PC7 is
taken HIGH at the end of this procedure.
The DAC8534 typically consumes 250µA at AVDD = 5V and
225µA at AVDD = 3V for each active channel, including
reference current consumption. Additional current consumption can occur at the digital inputs if VIH << IOVDD. For most
efficient power operation, CMOS logic levels are recommended at the digital inputs to the DAC.
In power-down mode, typical current consumption is 200nA
per channel. A delay time of 10ms to 20ms after a powerdown command is issued to the DAC is typically sufficient for
the power-down current to drop below 10µA.
DRIVING RESISTIVE AND CAPACITIVE LOADS
The DAC8534 output stage is capable of driving loads of up
to 1000pF while remaining stable. Within the offset and gain
error margins, the DAC8534 can operate rail-to-rail when
driving a capacitive load. Resistive loads of 2kΩ can be
driven by the DAC8534 while achieving a typical load regulation of 1%. As the load resistance drops below 2kΩ, the
load regulation error increases. When the outputs of the DAC
are driven to the positive rail under resistive loading, the
PMOS transistor of each Class-AB output stage can enter
into the linear region. When this occurs, the added IR voltage
drop deteriorates the linearity performance of the DAC. This
only occurs within approximately the top 20mV of the DAC’s
output voltage characteristic. The reference voltage applied
to the DAC8534 may be reduced below the supply voltage
applied to AVDD in order to eliminate this condition if good
linearity is a requirement at full-scale (under resistive loading
conditions).
CROSSTALK AND AC PERFORMANCE
The DAC8534 architecture uses separate resistor strings for
each DAC channel in order to achieve ultra-low crosstalk
performance. DC crosstalk seen at one channel during a full-
DAC8534
16
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SBAS254D
scale change on the neighboring channel is typically less than
0.5LSBs. The AC crosstalk measured (for a full-scale, 1kHz
sine wave output generated at one channel, and measured at
the remaining output channel) is typically under –100dB.
In addition, the DAC8534 can achieve typical AC performance of 96dB SNR (Signal-to-Noise Ratio) and 65dB THD
(Total Harmonic Distortion), making the DAC8534 a solid
choice for applications requiring high SNR at output frequencies at or below 4kHz.
OUTPUT VOLTAGE STABILITY
The DAC8534 exhibits excellent temperature stability of
5ppm/°C typical output voltage drift over the specified temperature range of the device. This enables the output voltage
of each channel to stay within a ±25µV window for a ±1°C
ambient temperature change.
Good Power-Supply Rejection Ratio (PSRR) performance
reduces supply noise present on AVDD from appearing at the
outputs to well below 10µV-s. Combined with good DC noise
performance and true 16-bit differential linearity, the DAC8534
becomes a perfect choice for closed-loop control applications.
USING THE REF02 AS A POWER SUPPLY FOR
THE DAC8534
Due to the extremely low supply current required by the
DAC8534, a possible configuration is to use a REF02 +5V
precision voltage reference to supply the required voltage to
the DAC8534's supply input as well as the reference input, as
shown in Figure 10. This is especially useful if the power
supply is quite noisy or if the system supply voltages are at
some value other than 5V. The REF02 will output a steady
supply voltage for the DAC8534. If the REF02 is used, the
current it needs to supply to the DAC8534 is 1.085mA typical
and 1.78mA max for AVDD = 5V. When a DAC output is
loaded, the REF02 also needs to supply the current to the
load. The total typical current required (with a 5kΩ load on a
given DAC output) is:
1.085mA + (5V/ 5kΩ) = 2.085mA
+15
+5V
REF02
SETTLING TIME AND OUTPUT
GLITCH PERFORMANCE
Settling time to within the 16-bit accurate range of the
DAC8534 is achievable within 10µs for a full-scale code
change at the input. Worst-case settling times between
consecutive code changes is typically less than 2µs, enabling update rates up to 500ksps for digital input signals
changing code-to-code. The high-speed serial interface of
the DAC8534 is designed in order to support these high
update rates.
For full-scale output swings, the output stage of each
DAC8534 channel typically exhibits less than 100mV of
overshoot and undershoot when driving a 200pF capacitive
load. Code-to-code change glitches are extremely low given
that the code-to-code transition does not cross an Nx4096
code boundary. Due to internal segmentation of the
DAC8534, code-to-code glitches occur at each crossing of
an Nx4096 code boundary. These glitches can approach
100nVs for N = 15, but settle out within ~2µs.
AIDD + IREF
3-Wire
Serial
Interface
SYNC
AVDD, VREF
SCLK
DAC8534
VOUT = 0V to 5V
DIN
FIGURE 10. REF02 as a Power Supply to the DAC8534.
BIPOLAR OPERATION USING THE DAC8534
The DAC8534 has been designed for single-supply operation, but a bipolar output range is also possible using the
circuit in Figure 11. The circuit shown will give an output
voltage range of ±VREF. Rail-to-rail operation at the amplifier
output is achievable using an amplifier such as the OPA703,
as shown in Figure 11.
R2
10kΩ
+5V
+5V
R1
10kΩ
OPA703
DAC8534
VOUTX
±5V
AVDD, VREF
10µF
0.1µF
-5V
(Other pins omitted for clarity.)
FIGURE 11. Bipolar Operation with the DAC8534.
DAC8534
SBAS254D
17
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The output voltage for any input code can be calculated as
follows:

 D   R1 + R 2 
VOUT X = VREF • 
– VREF
•
 65536   R1 

R 
•  2 
 R1  
where D represents the input code in decimal (0–65535).
With VREF = 5V, R1 = R2 = 10kΩ:
 10 • D 
VOUT X = 
 – 5V
 65536 
This is an output voltage range of ±5V with 0000H corresponding to a –5V output and FFFFH corresponding to a +5V
output. Similarly, using VREF = 2.5V, a ±2.5V output voltage
range can be achieved.
LAYOUT
A precision analog component requires careful layout, adequate bypassing, and clean, well-regulated power supplies.
The DAC8534 offers single-supply operation, and 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 switching speed, the more difficult it will be to keep digital noise
from appearing at the output.
Due to the single ground pin of the DAC8534, all return
currents, including digital and analog return currents for the
DAC, must flow through a single point. Ideally, GND would
be connected 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.
The power applied to AVDD should be well regulated and low
noise. Switching power supplies and DC/DC converters will
often have high-frequency glitches or spikes riding on the
output voltage. In addition, digital components can create
similar high-frequency 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, AVDD should be connected to
a positive 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, a 1µF to 10µF capacitor in
parallel with a 0.1µF bypass capacitor is 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 low-pass filter the supply, removing the highfrequency noise.
Up to four DAC8534 devices can be used on a single SPI bus
without any glue logic to create a high channel count solution. Special attention is required to avoid digital signal
integrity problems when using multiple DAC8534s on the
same SPI bus. Signal integrity of SYNC, SCLK, and DIN lines
will not be an issue as long as the rise times of these digital
signals are longer than six times the propagation delay
between any two DAC8534 devices. Propagation speed is
approximately six inches/ns on standard PCBs. Therefore, if
the digital signal risetime is 1ns, the distance between any
two DAC8534 devices is recommended not to exceed 1 inch.
If the DAC8534s have to be further apart on the PCB, the
signal rise times should be reduced by placing series resistors at the drivers for SYNC, SCLK, and DIN lines. If the
largest distance between any two DAC8534s has to be six
inches, the risetime should be reduced to 6ns with an RC
network formed by the series resistor at the digital driver and
the total trace and input capacitance on the PCB.
DAC8534
18
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SBAS254D
MECHANICAL DATA
MTSS001C – JANUARY 1995 – REVISED FEBRUARY 1999
PW (R-PDSO-G**)
PLASTIC SMALL-OUTLINE PACKAGE
14 PINS SHOWN
0,30
0,19
0,65
14
0,10 M
8
0,15 NOM
4,50
4,30
6,60
6,20
Gage Plane
0,25
1
7
0°– 8°
A
0,75
0,50
Seating Plane
0,15
0,05
1,20 MAX
PINS **
0,10
8
14
16
20
24
28
A MAX
3,10
5,10
5,10
6,60
7,90
9,80
A MIN
2,90
4,90
4,90
6,40
7,70
9,60
DIM
4040064/F 01/97
NOTES: A.
B.
C.
D.
All linear dimensions are in millimeters.
This drawing is subject to change without notice.
Body dimensions do not include mold flash or protrusion not to exceed 0,15.
Falls within JEDEC MO-153
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
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