FEATURES
AD5330: Single 8-Bit DAC in 20-Lead TSSOP
AD5331: Single 10-Bit DAC in 20-Lead TSSOP
AD5340: Single 12-Bit DAC in 24-Lead TSSOP
AD5341: Single 12-Bit DAC in 20-Lead TSSOP
Low Power Operation: 115 A @ 3 V, 140 A @ 5 V
Power-Down to 80 nA @ 3 V, 200 nA @ 5 V via PD Pin
2.5 V to 5.5 V Power Supply
Double-Buffered Input Logic
Guaranteed Monotonic by Design Over All Codes
Buffered/Unbuffered Reference Input Options
Output Range: 0–V
or 0–2 V
REF
REF
Power-On Reset to Zero Volts
Simultaneous Update of DAC Outputs via LDAC Pin
Asynchronous CLR Facility
Low Power Parallel Data Interface
On-Chip Rail-to-Rail Output Buffer Amplifiers
Temperature Range: –40ⴗC to +105ⴗC
APPLICATIONS
Portable Battery-Powered Instruments
Digital Gain and Offset Adjustment
Programmable Voltage and Current Sources
Programmable Attenuators
Industrial Process Control
AD5330/AD5331/AD5340/AD5341*
GENERAL DESCRIPTION
The AD5330/AD5331/AD5340/AD5341 are single 8-, 10-, and
12-bit DACs. They operate from a 2.5 V to 5.5 V supply consuming just 115 µA at 3 V, and feature a power-down mode that
further reduces the current to 80 nA. These devices incorporate
an on-chip output buffer that can drive the output to both
supply rails, while the AD5330, AD5340, and AD5341 allow a
choice of buffered or unbuffered reference input.
The AD5330/AD5331/AD5340/AD5341 have a parallel interface.
CS selects the device and data is loaded into the input registers
on the rising edge of WR.
The GAIN pin allows the output range to be set at 0 V to V
or 0 V to 2 × V
Input data to the DACs is double-buffered, allowing simultaneous
update of multiple DACs in a system using the LDAC pin.
An asynchronous CLR input is also provided, which resets the
contents of the Input Register and the DAC Register to all zeros.
These devices also incorporate a power-on reset circuit that ensures
that the DAC output powers on to 0 V and remains there until
valid data is written to the device.
The AD5330/AD5331/AD5340/AD5341 are available in Thin
Shrink Small Outline Packages (TSSOP).
REF
.
REF
AD5330 FUNCTIONAL BLOCK DIAGRAM
(Other Diagrams Inside)
POWER-ON
RESET
BUF
GAIN
DB
7
.
.
DB
CS
WR
CLR
LDAC
*Protected by U.S. Patent Number 5,969,657; other patents pending.
INTER-
FACE
0
LOGIC
REGISTER
RESET
INPUT
DAC
REGISTER
REV. 0
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
Temperature range: B Version: –40°C to +105°C; typical specifications are at 25°C.
3
Linearity is tested using a reduced code range: AD5330 (Code 8 to 255); AD5331 (Code 28 to 1023); AD5340/AD5341 (Code 115 to 4095).
4
DC specifications tested with output unloaded.
5
This corresponds to x codes. x = Deadband voltage/LSB size.
6
Guaranteed by design and characterization, not production tested.
7
In order for the amplifier output to reach its minimum voltage, Offset Error must be negative. In order for the amplifier output to reach its maximum voltage, V
“Offset plus Gain” Error must be positive.
Specifications subject to change without notice.
1
AD5330
Resolution8Bits
Relative Accuracy± 0.15± 1LSB
Differential Nonlinearity± 0.02± 0.25LSBGuaranteed Monotonic By Design Over All Codes
AD5331
Resolution10Bits
Relative Accuracy± 0.5± 4LSB
Differential Nonlinearity± 0.05± 0.5LSBGuaranteed Monotonic By Design Over All Codes
AD5340/AD5341
Resolution12Bits
Relative Accuracy± 2± 16LSB
Differential Nonlinearity± 0.2± 1LSBGuaranteed Monotonic By Design Over All Codes
Offset Error± 0.4± 3% of FSR
Gain Error± 0.15± 1% of FSR
Lower Deadband
Upper Deadband1060mVV
Offset Error Drift
Gain Error Drift
DC Power Supply Rejection Ratio
V
Input Range1V
REF
V
Input Impedance>10MΩBuffered Reference (AD5330, AD5340, and AD5341)
REF
Reference Feedthrough–90dBFrequency = 10 kHz
Minimum Output Voltage4,
Maximum Output Voltage
DC Output Impedance0.5Ω
Short Circuit Current25mAVDD = 5 V
Power-Up Time2.5µsComing Out of Power-Down Mode. VDD = 5 V
6
Input Current± 1µA
VIL, Input Low Voltage0.8VV
VIH, Input High Voltage2.4VVDD = 5 V ± 10%
Pin Capacitance3pF
V
DD
IDD (Normal Mode)DACs active and excluding load currents. Unbuffered
VDD = 4.5 V to 5.5 V140250µAReference. VIH = VDD, V
VDD = 2.5 V to 3.6 V115200µAI
IDD (Power-Down Mode)
VDD = 4.5 V to 5.5 V0.21µA
VDD = 2.5 V to 3.6 V0.081µA
= 2 V. RL = 2 k⍀ to GND; CL = 200 pF to GND; all specifications T
REF
B Version
2
MinTypMaxUnitConditions/Comments
3, 4
5
6
6
6
6
0.25V
1060mVLower Deadband Exists Only if Offset Error Is Negative
–12ppm of FSR/°C
–5ppm of FSR/°C
–60dB∆VDD = ±10%
DD
DD
VBuffered Reference (AD5330, AD5340, and AD5341)
VUnbuffered Reference
180kΩUnbuffered Reference. Gain = 1, Input Impedance = R
90kΩUnbuffered Reference. Gain = 2, Input Impedance = R
6
7
4, 7
0.001V minRail-to-Rail Operation
VDD–0.001V max
15mAVDD = 3 V
5µsComing Out of Power-Down Mode. VDD = 3 V
0.6VVDD = 3 V ± 10%
0.5VVDD = 2.5 V
2.1VVDD = 3 V ± 10%
2.0VVDD = 2.5 V
2.55.5V
to T
MIN
DD
DD
DD
In Buffered Mode extra current is (5 + V
where R
unless otherwise noted.)
MAX
= 5 V. Upper Deadband Exists Only if V
= 5 V ± 10%
= GND.
increases by 50 µA at V
is the resistance of the resistor string.
DAC
IL
> VDD – 100 mV.
REF
REF/RDAC
REF = VDD
= VDD and
REF
) µA,
DAC
DAC
–2–
REV. 0
Page 3
AD5330/AD5331/AD5340/AD5341
(VDD = 2.5 V to 5.5 V. RL = 2 k⍀ to GND; CL = 200 pF to GND; all specifications T
AC CHARACTERISTICS
Parameter
Output Voltage Settling TimeV
2
1
unless otherwise noted.)
B Version
MinTypMaxUnitConditions/Comments
3
= 2 V. See Figure 20
REF
AD533068µs1/4 Scale to 3/4 Scale Change (40 H to C0 H)
AD533179µs1/4 Scale to 3/4 Scale Change (100 H to 300 H)
AD5340810µs1/4 Scale to 3/4 Scale Change (400 H to C00 H)
AD5341810µs1/4 Scale to 3/4 Scale Change (400 H to C00 H)
Slew Rate0.7V/µs
Major Code Transition Glitch Energy6nV-s1 LSB Change Around Major Carry
Digital Feedthrough0.5nV-s
Multiplying Bandwidth200kHzV
Total Harmonic Distortion–70dBV
NOTES
1
Guaranteed by design and characterization, not production tested.
2
See Terminology section.
3
Temperature range: B Version: –40°C to +105°C; typical specifications are at 25 °C.
Specifications subject to change without notice.
= 2 V ± 0.1 V p-p. Unbuffered Mode
REF
= 2.5 V ± 0.1 V p-p. Frequency = 10 kHz
REF
MIN
to T
MAX
MIN
DATA,
GAIN,
HBEN
LDAC
LDAC
1, 2, 3
(VDD = 2.5 V to 5.5 V, All specifications T
, T
MAX
CS
WR
BUF,
1
2
CLR
NOTES:
1
SYNCHRONOUS LDAC UPDATE MODE
2
ASYNCHRONOUS LDAC UPDATE MODE
UnitCondition/Comments
t
1
t
6
to T
MIN
MAX
t
2
t
3
t
5
t
4
t
t
7
t
9
t
13
8
t
10
t
11
t
12
TIMING CHARACTERISTICS
ParameterLimit at T
t
1
t
2
t
3
t
4
t
5
t
6
t
7
t
8
t
9
t
10
t
11
t
12
t
13
NOTES
1
Guaranteed by design and characterization, not production tested.
2
All input signals are specified with tr = tf = 5 ns (10% to 90% of VDD) and timed from a voltage level of (VIL + VIH)/2.
3
See Figure 1.
0ns minCS to WR Setup Time
0ns minCS to WR Hold Time
20ns minWR Pulsewidth
5ns minData, GAIN, BUF, HBEN Setup Time
4.5ns minData, GAIN, BUF, HBEN Hold Time
5ns minSynchronous Mode. WR Falling to LDAC Falling.
5ns minSynchronous Mode. LDAC Falling to WR Rising.
4.5ns minSynchronous Mode. WR Rising to LDAC Rising.
5ns minAsynchronous Mode. LDAC Rising to WR Rising.
4.5ns minAsynchronous Mode. WR Rising to LDAC Falling.
20ns minLDAC Pulsewidth
20ns minCLR Pulsewidth
50ns minTime Between WR Cycles
Figure 1. Parallel Interface Timing Diagram
unless otherwise noted.)
REV. 0
–3–
Page 4
AD5330/AD5331/AD5340/AD5341
WARNING!
ESD SENSITIVE DEVICE
ABSOLUTE MAXIMUM RATINGS*
(TA = 25°C unless otherwise noted)
VDD to GND . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +7 V
Digital Input Voltage to GND . . . . . . . –0.3 V to V
Digital Output Voltage to GND . . . . . –0.3 V to V
Reference Input Voltage to GND . . . . –0.3 V to V
to GND . . . . . . . . . . . . . . . . . . . –0.3 V to VDD + 0.3 V
Time at Peak Temperature . . . . . . . . . . . . 10 sec to 40 sec
*Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those listed in the operational
sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
AD5330BRU–40°C to +105°CTSSOP (Thin Shrink Small Outline Package)RU-20
AD5331BRU–40°C to +105°CTSSOP (Thin Shrink Small Outline Package)RU-20
AD5340BRU–40°C to +105°CTSSOP (Thin Shrink Small Outline Package)RU-24
AD5341BRU–40°C to +105°CTSSOP (Thin Shrink Small Outline Package)RU-20
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily
accumulate on the human body and test equipment and can discharge without detection. Although
the AD5330/AD5331/AD5340/AD5341 features proprietary ESD protection circuitry, permanent
damage may occur on devices subjected to high-energy electrostatic discharges. Therefore, proper
ESD precautions are recommended to avoid performance degradation or loss of functionality.
–4–
REV. 0
Page 5
AD5330/AD5331/AD5340/AD5341
TOP VIEW
(Not to Scale)
20
19
18
17
16
15
14
13
12
11
1
2
3
4
5
6
7
8
9
10
AD5330
LDAC
GAIN
WR
CS
GND
BUF
V
REF
V
OUT
PD
V
DD
DB
0
DB
1
DB
2
DB
3
DB
4
DB
5
DB
6
DB
7
8-BIT
CLR
NC = NO CONNECT
NC
BUF
GAIN
DB
DB
CS
WR
CLR
LDAC
AD5330 FUNCTIONAL BLOCK DIAGRAM
BUFFER
V
DD
AD5330
POWER-DOWN
LOGIC
PD
GND
V
OUT
V
REF
POWER-ON
RESET
INPUT
7
.
.
INTER-
FACE
0
LOGIC
REGISTER
RESET
DAC
REGISTER
8-BIT
DAC
AD5330 PIN CONFIGURATION
AD5330 PIN FUNCTION DESCRIPTIONS
Pin
No.MnemonicFunction
1BUFBuffer Control Pin. This pin controls whether the reference input to the DAC is buffered or unbuffered.
2NCNo Connect.
3V
4V
REF
OUT
Reference Input.
Output of DAC. Buffered output with rail-to-rail operation.
5GNDGround reference point for all circuitry on the part.
6CSActive Low Chip Select Input. This is used in conjunction with WR to write data to the parallel interface.
7WRActive Low Write Input. This is used in conjunction with CS to write data to the parallel interface.
8GAINGain Control Pin. This controls whether the output range from the DAC is 0–V
or 0–2 V
REF
REF.
9CLRAsynchronous active low control input that clears all input registers and DAC registers to zero.
10LDACActive low control input that updates the DAC registers with the contents of the input registers.
11PDPower-Down Pin. This active low control pin puts the DAC into power-down mode.
12V
DD
Power Supply Input. These parts can operate from 2.5 V to 5.5 V and the supply should be decoupled
with a 10 µF capacitor in parallel with a 0.1 µF capacitor to GND.
13–20DB0–DB
7
Eight Parallel Data Inputs. DB7 is the MSB of these eight bits.
REV. 0
–5–
Page 6
AD5330/AD5331/AD5340/AD5341
BUF
DB
DB
WR
CLR
LDAC
CS
AD5331 FUNCTIONAL BLOCK DIAGRAM
V
REF
POWER-ON
RESET
INPUT
9
.
.
INTER-
FACE
0
LOGIC
REGISTER
RESET
DAC
REGISTER
10-BIT
DAC
V
AD5331
BUFFER
DD
POWER-DOWN
LOGIC
PD GND
V
OUT
AD5331 PIN CONFIGURATION
DB
DB
V
REF
V
OUT
GND
CS
WR
GAIN
CLR
LDAC
1
8
2
9
3
4
5
6
(Not to Scale)
7
8
9
10
10-BIT
AD5331
TOP VIEW
20
DB
7
19
DB
6
18
DB
5
17
DB
4
DB
16
3
15
DB
2
14
DB
1
DB
13
0
12
V
DD
11
PD
AD5331 PIN FUNCTION DESCRIPTIONS
Pin
No.MnemonicFunction
1DB
2DB
3V
4V
8
9
REF
OUT
Parallel Data Input.
Most Significant Bit of Parallel Data Input.
Unbuffered Reference Input.
Output of DAC. Buffered output with rail-to-rail operation.
5GNDGround reference point for all circuitry on the part.
6CSActive Low Chip Select Input. This is used in conjunction with WR to write data to the parallel interface.
7WRActive Low Write Input. This is used in conjunction with CS to write data to the parallel interface.
8GAINGain Control Pin. This controls whether the output range from the DAC is 0–V
or 0–2 V
REF
REF
.
9CLRActive low control input that clears all input registers and DAC registers to zero.
10LDACActive low control input that updates the DAC registers with the contents of the input registers.
11PDPower-Down Pin. This active low control pin puts the DAC into power-down mode.
12V
DD
Power Supply Input. These parts can operate from 2.5 V to 5.5 V and the supply should be decoupled
with a 10 µF capacitor in parallel with a 0.1 µF capacitor to GND.
13–20DB0–DB
7
Eight Parallel Data Inputs.
–6–
REV. 0
Page 7
AD5330/AD5331/AD5340/AD5341
AD5340 PIN CONFIGURATION
1
DB
10
DB
11
2
3
BUF
4
V
REF
V
5
OUT
6
NC
7
GND
8
CS
9
WR
10
GAIN
11
CLR
12
LDAC
NC = NO CONNECT
12-BIT
AD5340
TOP VIEW
(Not to Scale)
24
DB
9
23
DB
8
22
DB
7
21
DB
6
20
DB
5
19
DB
4
18
DB
3
17
DB
2
16
DB
1
15
DB
0
14
V
DD
13
PD
BUF
GAIN
DB
DB
CS
WR
CLR
LDAC
AD5340 FUNCTIONAL BLOCK DIAGRAM
V
REF
POWER-ON
RESET
INPUT
11
.
.
INTER-
FACE
0
LOGIC
REGISTER
RESET
DAC
REGISTER
12-BIT
DAC
V
AD5340
BUFFER
DD
POWER-DOWN
LOGIC
GND
PD
V
OUT
AD5340 PIN FUNCTION DESCRIPTIONS
Pin
No.MnemonicFunction
1DB
2DB
10
11
Parallel Data Input.
Most Significant Bit of Parallel Data Input.
3BUFBuffer Control Pin. This pin controls whether the reference input to the DAC is buffered or unbuffered.
4V
5V
REF
OUT
Reference Input.
Output of DAC. Buffered output with rail-to-rail operation.
6NCNo Connect.
7GNDGround reference point for all circuitry on the part.
8CSActive Low Chip Select Input. This is used in conjunction with WR to write data to the parallel interface.
9WRActive Low Write Input. This is used in conjunction with CS to write data to the parallel interface.
10GAINGain Control Pin. This controls whether the output range from the DAC is 0–V
or 0–2 V
REF
REF.
11CLRAsynchronous active low control input that clears all input registers and DAC registers to zero.
12LDACActive low control input that updates the DAC registers with the contents of the input registers.
13PDPower-Down Pin. This active low control pin puts the DAC into power-down mode.
14V
DD
Power Supply Input. These parts can operate from 2.5 V to 5.5 V and the supply should be decoupled
with a 10 µF capacitor in parallel with a 0.1 µF capacitor to GND.
15–24DB0–DB
9
10 Parallel Data Inputs.
REV. 0
–7–
Page 8
AD5330/AD5331/AD5340/AD5341
TOP VIEW
(Not to Scale)
20
19
18
17
16
15
14
13
12
11
1
2
3
4
5
6
7
8
9
10
AD5341
LDAC
GAIN
WR
CS
GND
V
REF
V
OUT
PD
V
DD
DB
0
DB
1
DB
2
DB
3
DB
4
DB
5
DB
6
DB
7
12-BIT
CLR
HBEN
BUF
AD5341 PIN CONFIGURATION
BUF
GAIN
DB
DB
HBEN
CS
WR
CLR
LDAC
AD5341 FUNCTIONAL BLOCK DIAGRAM
V
REF
POWER-ON
RESET
7
.
.
0
INTER-
FACE
LOGIC
RESET
HIGH BYTE
REGISTER
LOW BYTE
REGISTER
DAC
REGISTER
12-BIT
DAC
BUFFER
V
DD
AD5341
POWER-DOWN
LOGIC
PD
GND
V
OUT
AD5341 PIN FUNCTION DESCRIPTIONS
Pin
No.MnemonicFunction
1HBENHigh Byte Enable Pin. This pin is used when writing to the device to determine if data is written
to the high byte register or the low byte register.
2BUFBuffer Control Pin. This pin controls whether the reference input to the DAC is buffered or unbuffered.
3V
4V
REF
OUT
Reference Input.
Output of DAC. Buffered output with rail-to-rail operation.
5GNDGround reference point for all circuitry on the part.
6CSActive low Chip Select Input. This is used in conjunction with WR to write data to the parallel interface.
7WRActive Low Write Input. This is used in conjunction with CS to write data to the parallel interface.
8GAINGain Control Pin. This controls whether the output range from the DAC is 0–V
or 0–2 V
REF
REF.
9CLRAsynchronous active low control input that clears all input registers and DAC registers to zero.
10LDACActive low control input that updates the DAC registers with the contents of the input registers.
11PDPower-Down Pin. This active low control pin puts the DAC into power-down mode.
12V
DD
Power Supply Input. These parts can operate from 2.5 V to 5.5 V and the supply should be decoupled
with a 10 µF capacitor in parallel with a 0.1 µF capacitor to GND.
13–20DB0–DB
7
Eight Parallel Data Inputs. DB7 is the MSB of these eight bits.
–8–
REV. 0
Page 9
TERMINOLOGY
OUTPUT
VOLTAGE
DAC CODE
POSITIVE
OFFSET
GAIN ERROR
AND
OFFSET ERROR
ACTUAL
IDEAL
RELATIVE ACCURACY
For the DAC, Relative Accuracy or Integral Nonlinearity (INL)
is a measure of the maximum deviation, in LSBs, from a straight
line passing through the actual endpoints of the DAC transfer
function. Typical INL versus Code plot can be seen in Figures
5, 6, and 7.
DIFFERENTIAL NONLINEARITY
Differential Nonlinearity (DNL) is the difference between the
measured change and the ideal 1 LSB change between any two
adjacent codes. A specified differential nonlinearity of ± 1 LSB
maximum ensures monotonicity. This DAC is guaranteed monotonic by design. Typical DNL versus Code plot can be seen in
Figures 8, 9, and 10.
GAIN ERROR
This is a measure of the span error of the DAC (including any
error in the gain of the buffer amplifier). It is the deviation in
slope of the actual DAC transfer characteristic from the ideal
expressed as a percentage of the full-scale range. This is illustrated in Figure 2.
OFFSET ERROR
This is a measure of the offset error of the DAC and the output
amplifier. It is expressed as a percentage of the full-scale range.
If the offset voltage is positive, the output voltage will still be
positive at zero input code. This is shown in Figure 3. Because
the DACs operate from a single supply, a negative offset cannot
appear at the output of the buffer amplifier. Instead, there will
be a code close to zero at which the amplifier output saturates
(amplifier footroom). Below this code there will be a deadband
over which the output voltage will not change. This is illustrated
in Figure 4.
AD5330/AD5331/AD5340/AD5341
Figure 3. Positive Offset Error and Gain Error
OFFSET ERROR
OUTPUT
VOLTAGE
ACTUAL
IDEAL
NEGATIVE
OFFSET
DAC CODE
GAIN ERROR
AND
VOLTAGE
REV. 0
OUTPUT
DAC CODE
Figure 2. Gain Error
POSITIVE
GAIN ERROR
NEGATIVE
GAIN
ERROR
ACTUAL
IDEAL
–9–
DEADBAND CODES
AMPLIFIER
FOOTROOM
(~1mV)
NEGATIVE
OFFSET
Figure 4. Negative Offset Error and Gain Error
Page 10
AD5330/AD5331/AD5340/AD5341
OFFSET ERROR DRIFT
This is a measure of the change in Offset Error with changes in
temperature. It is expressed in (ppm of full-scale range)/°C.
GAIN ERROR DRIFT
This is a measure of the change in Gain Error with changes in
temperature. It is expressed in (ppm of full-scale range)/°C.
POWER-SUPPLY REJECTION RATIO (PSRR)
This indicates how the output of the DAC is affected by changes in
the supply voltage. PSRR is the ratio of the change in V
change in V
in dBs. V
REFERENCE FEEDTHROUGH
for full-scale output of the DAC. It is measured
DD
is held at 2 V and VDD is varied ± 10%.
REF
OUT
to a
This is the ratio of the amplitude of the signal at the DAC output
to the reference input when the DAC output is not being updated
(i.e., LDAC is high). It is expressed in dBs.
MAJOR-CODE TRANSITION GLITCH ENERGY
Major-Code Transition Glitch Energy is the energy of the
impulse injected into the analog output when the DAC changes
state. It is normally specified as the area of the glitch in nV secs
and is measured when the digital code is changed by 1 LSB at
the major carry transition (011 . . . 11 to 100 ...00 or 100...00
to 011 . . . 11).
DIGITAL FEEDTHROUGH
Digital Feedthrough is a measure of the impulse injected into
the analog output of the DAC from the digital input pins of the
device, but is measured when the DAC is not being written to
(CS held high). It is specified in nV secs and is measured with a
full-scale change on the digital input pins, i.e., from all 0s to all
1s and vice versa.
MULTIPLYING BANDWIDTH
The amplifiers within the DAC have a finite bandwidth. The
Multiplying Bandwidth is a measure of this. A sine wave on the
reference (with full-scale code loaded to the DAC) appears on
the output. The Multiplying Bandwidth is the frequency at which
the output amplitude falls to 3 dB below the input.
TOTAL HARMONIC DISTORTION
This is the difference between an ideal sine wave and its attenuated
version using the DAC. The sine wave is used as the reference
for the DAC and the THD is a measure of the harmonics present
on the DAC output. It is measured in dBs.
–10–
REV. 0
Page 11
Typical Performance Characteristics–
TA = 25ⴗC
V
DD
= 5V
CODE
DNL ERROR – LSBs
1.0
0.5
–1.0
01000400020003000
0
–0.5
AD5330/AD5331/AD5340/AD5341
1.0
TA = 25ⴗC
V
= 5V
DD
0.5
0
INL ERROR – LSBs
–0.5
–1.0
50250100150200
0
CODE
Figure 5. AD5330 Typical INL Plot
0.3
TA = 25ⴗC
V
= 5V
DD
0.2
0.1
0
–0.1
DNL ERROR – LSBs
–0.2
3
TA = 25ⴗC
V
= 5V
DD
2
1
0
–1
INL ERROR – LSBs
–2
–3
0
2001000
400600800
CODE
Figure 6. AD5331 Typical INL Plot
0.6
TA = 25ⴗC
V
= 5V
DD
0.4
0.2
0
–0.2
DNL ERROR – LSBs
–0.4
12
TA = 25ⴗC
= 5V
V
8
DD
4
0
–4
INL ERROR – LSBs
–8
–12
04000
100020003000
CODE
Figure 7. AD5340 Typical INL Plot
–0.3
050250
100150200
CODE
Figure 8. AD5330 Typical DNL Plot
1.00
0.75
0.50
0.25
0.00
–0.25
ERROR – LSBs
–0.50
–0.75
–1.00
2345
MAX INL
MAX DNL
MIN DNL
MIN INL
V
– V
REF
Figure 11. AD5330 INL and DNL
Error vs. V
REF
VDD = 5V
= 25ⴗC
T
A
–0.6
0
2001000
400600800
CODE
Figure 9. AD5331 Typical DNL Plot
1.00
VDD = 5V
0.75
0.50
0.25
–0.25
ERROR – LSBs
–0.50
–0.75
–1.00
= 3V
V
REF
MAX INLMAX DNL
0
MIN DNLMIN INL
–400120
4080
TEMPERATURE – ⴗC
Figure 12. AD5330 INL Error and
DNL Error vs. Temperature
Figure 10. AD5340 Typical DNL Plot
1.0
VDD = 5V
= 2V
V
REF
0.5
GAIN ERROR
0.0
ERROR – %
–0.5
–1.0
–4001204080
OFFSET ERROR
TEMPERATURE – ⴗC
Figure 13. AD5330 Offset Error
and Gain Error vs. Temperature
REV. 0
–11–
Page 12
AD5330/AD5331/AD5340/AD5341
DAC CODE
I
DD
– A
300
250
0
ZERO-SCALEFULL-SCALE
200
150
100
50
VDD = 3.6V
VDD = 5.5V
TA = 25ⴗC
V
REF
= 2V
CH1 500mV, CH2 5V, TIME BASE = 1s/DIV
CH1
CH2
TA = 25ⴰC
V
DD
= 5V
V
REF
= 2V
V
OUT
A
PD
0.2
TA = 25ⴰC
ERROR – %
0.1
–0.1
–0.2
–0.3
–0.4
–0.5
–0.6
= 2V
V
REF
0
OFFSET ERROR
013
25
VDD – Volts
GAIN ERROR
46
Figure 14. Offset Error and Gain
Error vs. V
300
200
– A
DD
I
100
0
2.55.5
DD
TA = 25ⴗC
3.05.0
3.54.04.5
VDD – Volts
Figure 17. Supply Current vs. Supply
Voltage
5
5V SOURCE
3
– Volts
OUT
2
V
1
0
013446
Figure 15. V
3V SOURCE
5V SINK
25
SINK/SOURCE CURRENT – mA
Source and Sink
OUT
3V SINK
Current Capability
0.5
TA = 25ⴗC
0.4
0.3
– A
DD
I
0.2
0.1
0
3.05.0
2.55.5
3.54.04.5
VDD – Volts
Figure 18. Power-Down Current vs.
Supply Voltage
Figure 16. Supply Current vs. DAC
Code
1800
TA = 25ⴗC
1600
1400
1200
1000
– A
DD
I
800
600
400
200
0
0
VDD = 5V
VDD = 3V
234
15
V
– Volts
LOGIC
Figure 19. Supply Current vs. Logic
Input Voltage
VDD = 5V
T
= 25ⴗC
CH2
CLK
V
OUT
CH1
CH1 1V, CH2 5V, TIME BASE = 5s/DIV
A
Figure 20. Half-Scale Settling (1/4 to
3/4 Scale Code Change)
TA = 25ⴰC
= 5V
V
DD
= 2V
V
REF
CH1
V
DD
V
A
CH2
CH1 2V, CH2 200mV, TIME BASE = 200s/DIV
OUT
Figure 21. Power-On Reset to 0 V
–12–
Figure 22. Exiting Power-Down to
Midscale
REV. 0
Page 13
AD5330/AD5331/AD5340/AD5341
VDD = 3V
FREQUENCY
120200190
IDD – A
VDD = 5V
1801701601501401301101009080
Figure 23. IDD Histogram with VDD =
3 V and V
0.4
0.2
0
= 5 V
DD
VDD = 5V
= 25ⴗC
T
A
0.917
0.916
0.915
0.914
0.913
0.912
0.911
0.910
0.909
0.908
0.907
0.906
0.905
0.904
0.903
250ns/DIV
Figure 24. AD5340 Major-Code Transition Glitch Energy
10
0
–10
–20
dB
–30
–40
–50
–60
0.01
0.11101001k10k
FREQUENCY – kHz
Figure 25. Multiplying Bandwidth
(Small-Signal Frequency Response)
FULL-SCALE ERROR – %FSR
–0.2
Figure 26. Full-Scale Error vs. V
2
1
34 50
V
– Volts
REF
REF
FUNCTIONAL DESCRIPTION
The AD5330/AD5331/AD5340/AD5341 are single resistor-string
DACs fabricated on a CMOS process with resolutions of 8, 10,
12, and 12 bits, respectively. They are written to using a parallel
interface. They operate from single supplies of 2.5 V to 5.5 V and
the output buffer amplifiers offer rail-to-rail output swing. The
AD5330, AD5340, and AD5341 have a reference input that may
be buffered to draw virtually no current from the reference
source. The reference input of the AD5331 is unbuffered. The
devices have a power-down feature that reduces current consumption to only 80 nA @ 3 V.
Digital-to-Analog Section
The architecture of one DAC channel consists of a reference
buffer and a resistor-string DAC followed by an output buffer
amplifier. The voltage at the V
pin provides the reference
REF
voltage for the DAC. Figure 27 shows a block diagram of the
DAC architecture. Since the input coding to the DAC is straight
binary, the ideal output voltage is given by:
VV
=××
OUTREF
D
Gain
N
2
where:
D = decimal equivalent of the binary code which is loaded to the
DAC register:
0–255 for AD5330 (8 Bits)
0–1023 for AD5331 (10 Bits)
0–4095 for AD5340/AD5341 (12 Bits)
N = DAC resolution
Gain = Output Amplifier Gain (1 or 2)
V
REF
INPUT
REGISTER
REFERENCE
DAC
REGISTER
BUFFER
RESISTOR
STRING
OUTPUT
BUFFER AMPLIFIER
GAIN
BUF
V
OUT
Figure 27. Single DAC Channel Architecture
REV. 0
–13–
Page 14
AD5330/AD5331/AD5340/AD5341
Resistor String
The resistor string section is shown in Figure 28. It is simply a
string of resistors, each of value R. The digital code loaded to
the DAC register determines at what node on the string the
voltage is tapped off to be fed into the output amplifier. The
voltage is tapped off by closing one of the switches connecting
the string to the amplifier. Because it is a string of resistors, it
is guaranteed monotonic.
V
REF
R
R
R
R
R
TO OUTPUT
AMPLIFIER
Figure 28. Resistor String
DAC Reference Input
There is a reference input pin for the DAC. The reference input
is buffered on the AD5330/AD5340/AD5341 but can be configured as unbuffered also. The reference input of the AD5331 is
unbuffered. The buffered/unbuffered option is controlled by the
BUF pin.
In buffered mode (BUF = 1), the current drawn from an external
reference voltage is virtually zero as the impedance is at least
10 MΩ. The reference input range is 1 V to 5 V with a 5 V supply.
In unbuffered mode (BUF = 0), the user can have a reference
voltage as low as 0.25 V and as high as V
since there is no
DD
restriction due to headroom and footroom of the reference amplifier. The impedance is still large at typically 180 kΩ for 0–V
mode and 90 kΩ for 0–2 V
mode. If there is an external
REF
REF
buffered reference (e.g., REF192) there is no need to use the
on-chip buffer.
Output Amplifier
The output buffer amplifier is capable of generating output
voltages to within 1 mV of either rail. Its actual range depends
on V
, GAIN, the load on V
REF
, and offset error.
OUT
If a gain of 1 is selected (GAIN = 0), the output range is 0.001 V
to V
.
REF
If a gain of 2 is selected (GAIN = 1), the output range is 0.001 V
to 2 V
is limited to V
. However, because of clamping, the maximum output
REF
– 0.001 V.
DD
The output amplifier is capable of driving a load of 2 kΩ to
GND or V
, in parallel with 500 pF to GND or VDD. The
DD
source and sink capabilities of the output amplifier can be seen
in Figure 15.
The slew rate is 0.7 V/µs with a half-scale settling time to
± 0.5 LSB (at eight bits) of 6 µs with the output unloaded. See
Figure 20.
PARALLEL INTERFACE
The AD5330, AD5331, and AD5340 load their data as a single
8-, 10-, or 12-bit word, while the AD5341 loads data as a low
byte of eight bits and a high byte containing four bits.
Double-Buffered Interface
The AD5330/AD5331/AD5340/AD5341 DACs all have doublebuffered interfaces consisting of an input register and a DAC
register. DAC data, BUF, and GAIN inputs are written to the input
register under control of the Chip Select (CS) and Write (WR).
Access to the DAC register is controlled by the LDAC function.
When LDAC is high, the DAC register is latched and the input
register may change state without affecting the contents of the
DAC register. However, when LDAC is brought low, the DAC
register becomes transparent and the contents of the input register
are transferred to it. The gain and buffer control signals are also
double-buffered and are only updated when LDAC is taken low.
Double-buffering is also useful where the DAC data is loaded in
two bytes, as in the AD5341, because it allows the whole data
word to be assembled in parallel before updating the DAC register.
This prevents spurious outputs that could occur if the DAC
register were updated with only the high byte or the low byte.
These parts contain an extra feature whereby the DAC register is not updated unless its input register has been updated
since the last time that LDAC was brought low. Normally,
when LDAC is brought low, the DAC register is filled with the
contents of the input register. In the case of the AD5330/AD5331/
AD5340/AD5341, the part will only update the DAC register if
the input register has been changed since the last time the DAC
register was updated. This removes unnecessary crosstalk.
Clear Input (CLR)
CLR is an active low, asynchronous clear that resets the input and
DAC registers.
Chip Select Input (CS)
CS is an active low input that selects the device.
Write Input (WR)
WR is an active low input that controls writing of data to the
device. Data is latched into the input register on the rising edge
of WR.
Load DAC Input (LDAC)
LDAC transfers data from the input register to the DAC register
(and hence updates the outputs). Use of the LDAC function enables
double-buffering of the DAC data, GAIN, and BUF. There
are two LDAC modes:
Synchronous Mode: In this mode the DAC register is updated
after new data is read in on the rising edge of the WR input.
LDAC can be tied permanently low or pulsed as in Figure 1.
Asynchronous Mode: In this mode the outputs are not updated
at the same time that the input register is written to. When LDAC
goes low, the DAC register is updated with the contents of the
input register.
High-Byte Enable Input (HBEN)
High-Byte Enable is a control input on the AD5341 only that
determines if data is written to the high-byte input register or
the low-byte input register.
–14–
REV. 0
Page 15
AD5330/AD5331/AD5340/AD5341
The low data byte of the AD5341 consists of data bits 0 to 7 at
data inputs DB
bits 8 to 11 at data inputs DB
to DB7 are ignored during a high-byte write, but they may
DB
4
to DB7, while the high byte consists of data
0
to DB3 as shown in Figure 29.
0
be used for data to set up the reference input as buffered/
unbuffered, and buffer amplifier gain. See Figure 33.
HIGH BYTE
XX
DB6DB7
X = UNUSED BIT
XX
LOW BYTE
DB4DB5
DB3
DB10DB11
DB2
DB8DB9
DB0DB1
Figure 29. Data Format for AD5341
POWER-ON RESET
The AD5330/AD5331/AD5340/AD5341 are provided with a
power-on reset function, so that they power up in a defined state.
The power-on state is:
• Normal Operation
• Reference Input Unbuffered
•0 – V
Output Range
REF
• Output Voltage Set to 0 V
Both input and DAC registers are filled with zeros and remain so
until a valid write sequence is made to the device. This is
particularly useful in applications where it is important to know
the state of the DAC outputs while the device is powering up.
POWER-DOWN MODE
The AD5330/AD5331/AD5340/AD5341 have low power consumption, dissipating only 0.35 mW with a 3 V supply and
0.7 mW with a 5 V supply. Power consumption can be further
reduced when the DAC is not in use by putting it into powerdown mode, which is selected by taking pin PD low.
When the PD pin is high, the DAC works normally with a
typical power consumption of 140 µA at 5 V (115 µA at 3 V).
In power-down mode, however, the supply current falls to
200 nA at 5 V (80 nA at 3 V) when the DAC is powered-down.
Not only does the supply current drop, but the output stage is
also internally switched from the output of the amplifier making it open-circuit. This has the advantage that the output is
three-state while the part is in power-down mode and provides a defined input condition for whatever is connected to
the output of the DAC amplifier. The output stage is illustrated in Figure 30.
RESISTOR
STRING DAC
AMPLIFIER
POWER-DOWN
CIRCUITRY
V
OUT
Figure 30. Output Stage During Power-Down
The bias generator, the output amplifier, the resistor string,
and all other associated linear circuitry are shut down when
the power-down mode is activated. However, the contents
of the registers are unaffected when in power-down. The time
to exit power-down is typically 2.5 µs for V
when V
= 3 V. This is the time from a rising edge on the
DD
= 5 V and 5 µs
DD
PD pin to when the output voltage deviates from its powerdown voltage. See Figure 22.
Table I. AD5330/AD5331/AD5340 Truth Table
CLRLDACCSWRFunction
111XNo Data Transfer
11X1No Data Transfer
0 XXXClear All Registers
1100➝1Load Input Register
1000➝1Load Input Register and DAC Register
10XXUpdate DAC Register
X = don’t care.
Table II. AD5341 Truth Table
CLRLDACCSWRHBENFunction
111XXNo Data Transfer
11X1XNo Data Transfer
0 XXXXClear All Registers
1100➝10Load Low-Byte Input Register
1100➝11Load High-Byte Input Register
1000➝10Load Low-Byte Input Register and DAC Register
1000➝11Load High-Byte Input Register and DAC Register
1 0 XXXUpdate DAC Register
X = don’t care.
REV. 0
–15–
Page 16
AD5330/AD5331/AD5340/AD5341
SUGGESTED DATABUS FORMATS
In most applications GAIN and BUF are hard-wired. However,
if more flexibility is required, they can be included in a databus.
This enables you to software program GAIN, giving the option
of doubling the resolution in the lower half of the DAC range.
In a bused system, GAIN and BUF may be treated as data inputs
since they are written to the device during a write operation and
take effect when LDAC is taken low. This means that the reference buffers and the output amplifier gain of multiple DAC
devices can be controlled using common GAIN and BUF lines.
In the case of the AD5330 this means that the databus must be
wider than eight bits. The AD5331 and AD5340 databuses must
be at least 10 and 12 bits wide respectively and are best suited
to a 16-bit databus system.
Examples of data formats for putting GAIN and BUF on a 16bit databus are shown in Figure 31. Note that any unused bits
above the actual DAC data may be used for BUF and GAIN.
DAC devices can be controlled using common GAIN and
BUF lines.
AD5330
XX
GAIN
BUFXX
GAINBUFXX
X = UNUSED BIT
DB11
XX
XX
DB10
X
XBUF
AD5331
DB9 DB8
AD5340
DB9 DB8
DB7GAIN
DB7
DB6
DB6
DB5
DB5DB6DB7
DB5
DB4
DB0DB1DB2DB3DB4
DB0
DB1DB2DB3DB4
DB1DB2DB3
DB0
Figure 31. GAIN and BUF Data on a 16-Bit Bus
The AD5341 is a 12-bit device that uses byte load, so only four
bits of the high byte are actually used as data. Two of the unused
bits can be used for GAIN and BUF data by connecting them
to the GAIN and BUF inputs; e.g., Bits 6 and 7, as shown in
Figures 32 and 33.
8-BIT
DATA BUS
DB
DATA
INPUTS
7DB6
BUF
AD5341
GAIN
LDAC
CLR
CS
WR
HBEN
Figure 32. AD5341 Data Format for Byte Load with GAIN
and BUF Data on 8-Bit Bus
In this case, the low byte is written first in a write operation
with HBEN = 0. Bits 6 and 7 of DAC data will be written into
GAIN and BUF registers but will have no effect. The high byte
is then written. Only the lower four bits of data are written into the
DAC high byte register, so Bits 6 and 7 can be GAIN and BUF
data.
LDAC is used to update the DAC, GAIN and BUF values.
APPLICATIONS INFORMATION
Typical Application Circuits
The AD5330/AD5331/AD5340/AD5341 can be used with a
wide range of reference voltages, especially if the reference inputs
are configured to be unbuffered, in which case the devices offer
full, one-quadrant multiplying capability over a reference range
of 0.25 V to V
. More typically, these devices may be used with a
DD
fixed, precision reference voltage. Figure 34 shows a typical
setup for the devices when using an external reference connected to
the unbuffered reference inputs. If the reference inputs are unbuffered, the reference input range is from 0.25 V to VDD, but if the
on-chip reference buffers are used, the reference range is reduced.
Suitable references for 5 V operation are the AD780 and REF192.
For 2.5 V operation, a suitable external reference would be the
AD589, a 1.23 V bandgap reference.
V
= 2.5V TO 5.5V
DD
10F
V
V
REF
DD
AD5330/AD5331/
V
OUT
EXT
REF
V
GND
0.1F
IN
V
OUT
AD5340/AD5341
AD780/REF192
= 5V
WITH V
OR
AD589 WITH V
DD
= 2.5V
DD
GND
Figure 34. AD5330/AD5331/AD5340/AD5341 Using
External Reference
Driving VDD From the Reference Voltage
If an output range of zero to VDD is required, the simplest solution is to connect the reference inputs to V
. As this supply may
DD
not be very accurate, and may be noisy, the devices may be
powered from the reference voltage, for example using a 5 V
reference such as the ADM663 or ADM666, as shown in
Figure 35.
6V TO 16V
0.1F
10F
V
DD
V
REF
AD5330/AD5331/
AD5340/AD5341
GND
V
OUT
V
IN
ADM663/ADM666
SENSE
V
GND
OUT(2)
VSETSHDN
0.1F
HIGH BYTE
BUF GAIN
DB6DB7
X = UNUSED BIT
X
X
LOW BYTE
DB4DB5
DB3
DB10DB11
DB2
DB8DB9
DB0DB1
Figure 33. AD5341 with GAIN and BUF Data on 8-Bit Bus
Figure 35. Using an ADM663/ADM666 as Power and Reference to AD5330/AD5331/AD5340/AD5341
–16–
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Page 17
AD5330/AD5331/AD5340/AD5341
Bipolar Operation Using the AD5330/AD5331/AD5340/AD5341
The AD5330/AD5331/AD5340/AD5341 have been designed
for single supply operation, but bipolar operation is achievable
using the circuit shown in Figure 36. The circuit shown has been
configured to achieve an output voltage range of –5 V < V
<
O
+5 V. Rail-to-rail operation at the amplifier output is achievable
using an AD820 or OP295 as the output amplifier.
The output voltage for any input code can be calculated as
follows:
VO= [(1 + R4/R3) × (R2/(R1 + R2) × (2 × V
REF
× D/
N
2
)] – R4 × V
REF
/R3
where:
D is the decimal equivalent of the code loaded to the DAC, N is
DAC resolution and V
is the reference voltage input.
REF
With:
V
= 2.5 V
REF
R1 = R3 = 10 kΩ
R2 = R4 = 20 kΩ and V
V
= (10 × D/2N) – 5
OUT
0.1F
V
IN
EXT
V
GND
OR
OUT
0.1F
= 5V
DD
= 2.5V
DD
REF
AD780/REF192
WITH V
AD589 WITH V
= 5 V.
DD
VDD = 5V
10F
V
DD
V
REF
AD5330/AD5331/
AD5340/AD5341
GND
R3
10k⍀
V
OUT
R1
10k⍀
R4
20k⍀
R2
20k⍀
+5V
ⴞ5V
–5V
Figure 36. Bipolar Operation using the AD5330/AD5331/
AD5340/AD5341
Decoding Multiple AD5330/AD5331/AD5340/AD5341
The CS pin on these devices can be used in applications to decode
a number of DACs. In this application, all DACs in the system
receive the same data and WR pulses, but only the CS to one of
the DACs will be active at any one time, so data will only be
written to the DAC whose CS is low. If multiple AD5341s are
being used, a common HBEN line will also be required to
determine if the data is written to the high-byte or low-byte
register of the selected DAC.
The 74HC139 is used as a 2- to 4-line decoder to address any
of the DACs in the system. To prevent timing errors, the enable
input should be brought to its inactive state while the coded
address inputs are changing state. Figure 37 shows a diagram of a
typical setup for decoding multiple devices in a system. Once
data has been written sequentially to all DACs in a system, all the
DACs can be updated simultaneously using a common LDAC
line. A common CLR line can also be used to reset all DAC
outputs to zero.
AD5330/AD5331/
AD5340/AD5341
HBEN
WR
LDAC
CLR
ENABLE
CODED
ADDRESS
1G
1A
1B
V
DD
V
CC
74HC139
DGND
1Y0
1Y1
1Y2
1Y3
HBEN*
WR
LDAC
CLR
CS
AD5330/AD5331/
AD5340/AD5341
HBEN*
WR
LDAC
CLR
CS
AD5330/AD5331/
AD5340/AD5341
HBEN*
WR
LDAC
CLR
CS
AD5330/AD5331/
AD5340/AD5341
HBEN*
WR
LDAC
CLR
CS
*AD5341 ONLY
DATA
INPUTS
DATA
INPUTS
DATA
INPUTS
DATA
INPUTS
DATA BUS
Figure 37. Decoding Multiple DAC Devices
REV. 0
–17–
Page 18
AD5330/AD5331/AD5340/AD5341
Programmable Current Source
Figure 38 shows the AD5330/AD5331/AD5340/AD5341 used
as the control element of a programmable current source. In this
example, the full-scale current is set to 1 mA. The output voltage from the DAC is applied across the current setting resistor
of 4.7 kΩ in series with the 470 Ω adjustment potentiometer,
which gives an adjustment of about ±5%. Suitable transistors to
place in the feedback loop of the amplifier include the BC107
and the 2N3904, which enable the current source to operate
from a minimum V
of 6 V. The operating range is deter-
SOURCE
mined by the operating characteristics of the transistor. Suitable
amplifiers include the AD820 and the OP295, both having railto-rail operation on their outputs. The current for any digital
input code and resistor value can be calculated as follows:
D
N
mA
R
×()2
Where:
IGV
=××
REF
G is the gain of the buffer amplifier (1 or 2)
D is the digital equivalent of the digital input code
N is the DAC resolution (8, 10, or 12 bits)
R is the sum of the resistor plus adjustment potentiometer in kΩ
VDD = 5V
10F
V
DD
V
REF
AD5330/AD5331/
AD5340/AD5341
V
OUT
5V
AD820/
OP295
V
SOURCE
LOAD
EXT
REF
V
GND
0.1F
IN
V
OUT
0.1F
Power Supply Bypassing and Grounding
In any circuit where accuracy is important, careful consideration
of the power supply and ground return layout helps to ensure
the rated performance. The printed circuit board on which the
AD5330/AD5331/AD5340/AD5341 is mounted should be
designed so that the analog and digital sections are separated,
and confined to certain areas of the board. If the device is in a
system where multiple devices require an AGND-to-DGND
connection, the connection should be made at one point only.
The star ground point should be established as closely as possible to the device. The AD5330/AD5331/AD5340/AD5341
should have ample supply bypassing of 10 µF in parallel with
0.1 µF on the supply located as close to the package as pos-
sible, ideally right up against the device. The 10 µF capacitors
are the tantalum bead type. The 0.1 µF capacitor should have
low Effective Series Resistance (ESR) and Effective Series Inductance (ESI), like the common ceramic types that provide a low
impedance path to ground at high frequencies to handle transient currents due to internal logic switching.
The power supply lines of the device should use as large a trace
as possible to provide low impedance paths and reduce the effects
of glitches on the power supply line. Fast switching signals such
as clocks should be shielded with digital ground to avoid radiating noise to other parts of the board, and should never be run
near the reference inputs. Avoid crossover of digital and analog signals. Traces on opposite sides of the board should run
at right angles to each other. This reduces the effects of feedthrough through the board. A microstrip technique is by far
the best, but not always possible with a double-sided board. In
this technique, the component side of the board is dedicated to
ground plane while signal traces are placed on the solder side.