Analog Devices AD5302, AD5322, AD5312 Datasheet

+2.5 V to +5.5 V, 230 ␮A Dual Rail-to-Rail,

a

FEATURES
AD5302: Two 8-Bit Buffered DACs in One Package
AD5312: Two 10-Bit Buffered DACs in One Package
AD5322: Two 12-Bit Buffered DACs in One Package
10-Lead ␮SOIC Package
Micropower Operation: 300 ␮A @ 5 V (Including

Reference Current)
Power-Down to 200 nA @ 5 V, 50 nA @ 3 V
+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 Voltage

0–V

REF

Power-On-Reset to Zero Volts
Simultaneous Update of DAC Outputs via LDAC
Low Power Serial Interface with Schmitt-Triggered

Inputs
On-Chip Rail-to-Rail Output Buffer Amplifiers

APPLICATIONS
Portable Battery-Powered Instruments
Digital Gain and Offset Adjustment
Programmable Voltage and Current Sources
Programmable Attenuators

Voltage Output 8-/10-/12-Bit DACs

AD5302/AD5312/AD5322*

GENERAL DESCRIPTION

The AD5302/AD5312/AD5322 are dual 8-, 10- and 12-bit buff-

ered voltage output DACs in a 10-lead µSOIC package that

operate from a single +2.5 V to +5.5 V supply consuming

230 µA at 3 V. Their on-chip output amplifiers allow the outputs
to swing rail-to-rail with a slew rate of 0.7 V/µs. The AD5302/

AD5312/AD5322 utilize a versatile 3-wire serial interface which
operates at clock rates up to 30 MHz and is compatible with
standard SPI™, QSPI™, MICROWIRE™ and DSP interface
standards.

The references for the two DACs are derived from two reference
pins (one per DAC). The reference inputs may be configured as
buffered or unbuffered inputs. The outputs of both DACs may
be updated simultaneously using the asynchronous LDAC in­put. The parts incorporate a power-on-reset circuit that ensures
that the DAC outputs power-up to 0 V and remain there until a
valid write takes place to the device. The parts contain a power­down feature that reduces the current consumption of the
devices to 200 nA at 5 V (50 nA at 3 V) and provides software­selectable output loads while in power-down mode.

The low power consumption of these parts in normal operation
make them ideally suited to portable battery operated equip­ment. The power consumption is 1.5 mW at 5 V, 0.7 mW at

3 V, reducing to 1 µW in power-down mode.

FUNCTIONAL BLOCK DIAGRAM

V

DD

POWER-ON

RESET

INPUT

REGISTER

SYNC

SCLK

DIN

*Patent Pending; protected by U.S. Patent No. 5684481.
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corporation.

INTERFACE

LOGIC

LDAC

INPUT

REGISTER

DAC

REGISTER

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.

V

A

REF

AD5302/AD5312/AD5322

STRING

DAC

POWER-DOWN

LOGIC

STRING

DAC

V

B

REF

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] World Wide Web Site: http://www.analog.com
Fax: [phone] © Analog Devices, Inc., 1999

BUFFER

BUFFER

GND

RESISTOR
NETWORK

RESISTOR
NETWORK

V

A

OUT

V

B

OUT

AD5302/AD5312/AD5322–SPECIFICATIONS

to GND; CL = 200 pF to GND; all specifications T

Parameter

1

DC PERFORMANCE

3, 4

B Version
Min Typ Max Units Conditions/Comments

MIN

to T

unless otherwise noted.)

MAX

2

(VDD = +2.5 V to +5.5 V; V

= +2 V; RL = 2 k⍀

REF

AD5302

Resolution 8 Bits

Relative Accuracy ±0.15 ±1LSB
Differential Nonlinearity ±0.02 ±0.25 LSB Guaranteed Monotonic by Design Over All Codes

AD5312

Resolution 10 Bits

Relative Accuracy ±0.5 ±3LSB
Differential Nonlinearity ±0.05 ±0.5 LSB Guaranteed Monotonic by Design Over All Codes

AD5322

Resolution 12 Bits

Relative Accuracy ±2 ±12 LSB

Differential Nonlinearity ±0.2 ±1 LSB Guaranteed Monotonic by Design Over All Codes
Offset Error ±0.4 ±3 % of FSR See Figures 2 and 3
Gain Error ±0.15 ±1 % of FSR See Figures 2 and 3

Lower Deadband 10 60 mV See Figures 2 and 3
Offset Error Drift
Gain Error Drift
Power Supply Rejection Ratio
DC Crosstalk

DAC REFERENCE INPUTS

V

Input Range 1 V

REF

Input Impedance >10 MΩ Buffered Reference Mode

V

REF

5

5

5

5

5

0V

–12 ppm of FSR/°C
–5 ppm of FSR/°C
–60 dB ∆VDD = ±10%
30 µV

DD

DD

V Buffered Reference Mode
V Unbuffered Reference Mode

180 kΩ Unbuffered Reference Mode, Input Impedance = R

Reference Feedthrough –90 dB Frequency = 10 kHz
Channel-to-Channel Isolation –80 dB Frequency = 10 kHz

OUTPUT CHARACTERISTICS

Minimum Output Voltage
Maximum Output Voltage

5

6

6

0.001 V min This is a measure of the minimum and maximum
VDD – 0.001 V max drive capability of the output amplifier.

DC Output Impedance 0.5 Ω

Short Circuit Current 50 mA V

20 mA V

Power-Up Time 2.5 µs Coming Out of Power-Down Mode. V

5 µs Coming Out of Power-Down Mode. V

LOGIC INPUTS

5

= +5 V

DD

= +3 V

DD

= +5 V

DD

= +3 V

DD

Input Current ±1 µA

, Input Low Voltage 0.8 V V

V

IL

0.6 V V

0.5 V V

, Input High Voltage 2.4 V V

V

IH

2.1 V V

2.0 V V

= +5 V ± 10%

DD

= +3 V ± 10%

DD

= +2.5 V

DD

= +5 V ± 10%

DD

= +3 V ± 10%

DD

= +2.5 V

DD

Pin Capacitance 2 3.5 pF

POWER REQUIREMENTS

V

DD

(Normal Mode) Both DACs Active and Excluding Load Currents

I

DD

= +4.5 V to +5.5 V 300 450 µA Both DACs in Unbuffered Mode. V

V

DD

= +2.5 V to +3.6 V 230 350 µAV

V

DD

(Full Power-Down)

I

DD

= +4.5 V to +5.5 V 0.2 1 µA

V

DD

V

= +2.5 V to +3.6 V 0.05 1 µA

DD

NOTES

1

See Terminology.

2

Temperature range: B Version: –40°C to +105°C.

3

DC specifications tested with the outputs unloaded.

4

Linearity is tested using a reduced code range: AD5302 (Code 8 to 248); AD5312 (Code 28 to 995); AD5322 (Code 115 to 3981).

5

Guaranteed by design and characterization, not production tested.

6

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

= VDD and “Offset plus Gain” Error must be positive.

REF

2.5 5.5 V IDD Specification Is Valid for All DAC Codes

= VDD and

= GND. In Buffered Mode, extra current is

IL

typically x µA per DAC where x = 5 µA + V

IH

REF/RDAC

Specifications subject to change without notice.

DAC

.

–2–

REV. 0

AD5302/AD5312/AD5322

(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 Time V

2

1

otherwise noted.)

B Version

3

Min Typ Max Units Conditions/Comments

= VDD = +5 V

REF

AD5302 6 8 µs 1/4 Scale to 3/4 Scale Change (40 Hex to C0 Hex)
AD5312 7 9 µs 1/4 Scale to 3/4 Scale Change (100 Hex to 300 Hex)
AD5322 8 10 µs 1/4 Scale to 3/4 Scale Change (400 Hex to C00 Hex)

Slew Rate 0.7 V/µs

Major-Code Transition Glitch Energy 12 nV-s 1 LSB Change Around Major Carry (011 . . . 11 to 100 . . . 00)
Digital Feedthrough 0.10 nV-s
Analog Crosstalk 0.01 nV-s
DAC-to-DAC Crosstalk 0.01 nV-s
Multiplying Bandwidth 200 kHz V
Total Harmonic Distortion –70 dB V

NOTES

1

Guaranteed by design and characterization, not production tested.

2

See Terminology.

3

Temperature range: B Version: –40°C to +105°C.

Specifications subject to change without notice.

1, 2, 3

TIMING CHARACTERISTICS

Limit at T

MIN

, T

(VDD = +2.5 V to +5.5 V; all specifications T

MAX

= 2 V ± 0.1 V p-p. Unbuffered Mode

REF

= 2.5 V ± 0.1 V p-p. Frequency = 10 kHz

REF

to T

MIN

unless otherwise noted)

MAX

Parameter (B Version) Units Conditions/Comments

t

1

t

2

t

3

t

4

t

5

t

6

t

7

t

8

t

9

t

10

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.

Specifications subject to change without notice.

33 ns min SCLK Cycle Time
13 ns min SCLK High Time
13 ns min SCLK Low Time
0 ns min SYNC to SCLK Active Edge Setup Time
5 ns min Data Setup Time

4.5 ns min Data Hold Time
0 ns min SCLK Falling Edge to SYNC Rising Edge
100 ns min Minimum SYNC High Time
20 ns min LDAC Pulsewidth
20 ns min SCLK Falling Edge to LDAC Rising Edge

MIN

to T

MAX

unless

t

1

SCLK

t

t

t

8

SYNC

DIN*

LDAC

LDAC

*SEE PAGE 11 FOR DESCRIPTION OF INPUT REGISTER

DB15

t

4

t

6

t

5

3

2

Figure 1. Serial Interface Timing Diagram

REV. 0 –3–

DB0

t

7

t

9

t

10

AD5302/AD5312/AD5322

WARNING!

ESD SENSITIVE DEVICE

ABSOLUTE MAXIMUM RATINGS

(T

= +25°C unless otherwise noted)

A

1, 2

PIN CONFIGURATION

VDD to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +7 V

Digital Input Voltage to GND . . . . . . . . .–0.3 V to V

Reference Input Voltage to GND . . . . . –0.3 V to V

V

OUT

A, V

to GND . . . . . . . . . . . . . –0.3 V to VDD + 0.3 V

OUTB

+ 0.3 V

DD

+ 0.3 V

DD

Operating Temperature Range

Industrial (B Version) . . . . . . . . . . . . . . . . –40°C to +105°C

Storage Temperature Range . . . . . . . . . . . . . –65°C to +150°C

Junction Temperature (T

Max) . . . . . . . . . . . . . . . . . .+150°C

J

LDAC

V

REF

V

REF

V

OUT

V

DD

B
A
A

1

2

AD5302/
AD5312/

3

AD5322

TOP VIEW

4

(Not to Scale)

5

10

GND

9

DIN

8

SCLK

7

SYNC

6

B

V

OUT

10-Lead µSOIC Package

Power Dissipation . . . . . . . . . . . . . . . . . . . (T

Max–T

J

)/θ

A

JA

θJA Thermal Impedance . . . . . . . . . . . . . . . . . . . . . 206°C/W

θ

Thermal Impedance . . . . . . . . . . . . . . . . . . . . . . 44°C/W

JC

Lead Temperature, Soldering

Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . .+215°C

Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . .+220°C

NOTES

1

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.

2

Transient currents of up to 100 mA will not cause SCR latch-up.

ORDERING GUIDE

Temperature Package Package Branding

Model Range Description Option Information

AD5302BRM –40°C to +105°C µSOIC RM-10 D5B
AD5312BRM –40°C to +105°C µSOIC RM-10 D6B
AD5322BRM –40°C to +105°C µSOIC RM-10 D7B

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 AD5302/AD5312/AD5322 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 functionalit y.

–4–

REV. 0

AD5302/AD5312/AD5322

PIN FUNCTION DESCRIPTIONS

Pin No. Mnemonic Function

1 LDAC Active low control input that transfers the contents of the input registers to their respective DAC regis-

ters. Pulsing this pin low allows either or both DAC registers to be updated if the input registers have new
data. This allows simultaneous update of both DAC outputs

2V

3V

4V

5V
6V

DD

B Reference Input Pin for DAC B. This is the reference for DAC B. It may be configured as a buffered or

REF

A Reference Input Pin for DAC A. This is the reference for DAC A. It may be configured as a buffered or

REF

A Buffered Analog Output Voltage from DAC A. The output amplifier has rail-to-rail operation.

OUT

B Buffered Analog Output Voltage from DAC B. The output amplifier has rail-to-rail operation.

OUT

7 SYNC Active Low Control Input. This is the frame synchronization signal for the input data. When SYNC goes

8 SCLK Serial Clock Input. Data is clocked into the input shift register on the falling edge of the serial clock in-

9 DIN Serial Data Input. This device has a 16-bit input shift register. Data is clocked into the register on the

10 GND Ground reference point for all circuitry on the part.

Power Supply Input. These parts can be operated from +2.5 V to +5.5 V and the supply should be de­coupled to GND.

an unbuffered input, depending on the BUF bit in the control word of DAC B. It has an input range
from 0 V to V

in unbuffered mode and from 1 V to VDD in buffered mode.

DD

an unbuffered input depending on the BUF bit in the control word of DAC A. It has an input range from
0 V to V

in unbuffered mode and from 1 V to VDD in buffered mode.

DD

low, it powers on the SCLK and DIN buffers and enables the input shift register. Data is transferred in
on the falling edges of the following 16 clocks. If SYNC is taken high before the 16th falling edge, the
rising edge of SYNC acts as an interrupt and the write sequence is ignored by the device.

put. Data can be transferred at rates up to 30 MHz. The SCLK input buffer is powered down after each
write cycle.

falling edge of the serial clock input. The DIN input buffer is powered down after each write cycle.

TERMINOLOGY

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. A typical INL vs. code plot can be seen in Figure 4.

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. A typical DNL vs. code plot can be seen
in Figure 7.

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.

GAIN ERROR

This is a measure of the span error of the DAC. It is the devia­tion in slope of the actual DAC transfer characteristic from the
ideal expressed as a percentage of the full-scale range.

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 tem-

perature. It is expressed in (ppm of full-scale range)/°C.

MAJOR-CODE TRANSITION GLITCH ENERGY

Major-code transition glitch energy is the energy of the impulse
injected into the analog output when the code in the DAC regis­ter 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
(SYNC 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.

ANALOG CROSSTALK

This is the glitch impulse transferred to the output of one DAC
due to a change in the output of the other DAC. It is measured
by loading one of the input registers with a full-scale code change
(all 0s to all 1s and vice versa) while keeping LDAC high. Then
pulse LDAC low and monitor the output of the DAC whose
digital code was not changed. The area of the glitch is expressed
in nV-secs.

REV. 0

–5–

AD5302/AD5312/AD5322

DAC-TO-DAC CROSSTALK

This is the glitch impulse transferred to the output of one DAC
due to a digital code change and subsequent output change of
the other DAC. This includes both digital and analog crosstalk.
It is measured by loading one of the DACs with a full-scale code
change (all 0s to all 1s and vice versa) while keeping LDAC low
and monitoring the output of the other DAC. The area of the
glitch is expressed in nV-secs.

DC CROSSTALK

This is the dc change in the output level of one DAC in re­sponse to a change in the output of the other DAC. It is mea­sured with a full-scale output change on one DAC while

monitoring the other DAC. It is expressed in µV.

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

to a change in VDD for full-scale output of the DAC. It is

V

OUT

measured in dBs. V

is held at +2 V and V

REF

is varied ±10%.

DD

REFERENCE FEEDTHROUGH

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.

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.

CHANNEL-TO-CHANNEL ISOLATION

This is a ratio of the amplitude of the signal at the output of one
DAC to a sine wave on the reference input of the other DAC. It
is measured in dBs.

GAIN ERROR

PLUS

OFFSET ERROR

OUTPUT

VOLTAGE

POSITIVE

OFFSET

ERROR

AMPLIFIER

FOOTROOM

(1mV)

NEGATIVE

OFFSET

ERROR

IDEAL

ACTUAL

DAC CODE

DEADBAND

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.

Figure 2. Transfer Function with Negative Offset

GAIN ERROR

PLUS

OFFSET ERROR

OUTPUT

VOLTAGE

POSITIVE

OFFSET

ERROR

ACTUAL

IDEAL

DAC CODE

Figure 3. Transfer Function with Positive Offset

–6–

REV. 0

Typical Performance Characteristics–

AD5302/AD5312/AD5322

1.0
TA = +258C

V

= +5V

DD

0.5

0

INL ERROR – LSBs

–0.5

–1.0

50 250100 150 200

0

CODE

Figure 4. AD5302 Typical INL Plot

0.3

TA = +258C
V

= +5V

DD

0.2

0.1

0

–0.1

DNL ERROR – LSBs

–0.2

3

TA = +258C

= +5V

V

DD

2

1

0

–1

INL ERROR – LSBs

–2

–3

0

400 600 800

200 1000

CODE

Figure 5. AD5312 Typical INL Plot

0.6
TA = +258C

V

= +5V

DD

0.4

0.2

0

–0.2

DNL ERROR – LSBs

–0.4

12

TA = +258C

= +5V

V

8

DD

4

0

–4

INL ERROR – LSBs

–8

–12

0 4000

1000 2000 3000

CODE

Figure 6. AD5322 Typical INL Plot

1.0
TA = +258C
VDD = +5V

0.5

0

DNL ERROR – LSBs

–0.5

–0.3

0 50 250100 150 200

CODE

Figure 7. AD5302 Typical DNL Plot

1.0

.75

.50

.25

0

–.25

ERROR – LSBs

–.50

–.75

–1.0

2345

MAX INL
MAX DNL

MIN DNL
MIN INL

V

REF

– Volts

VDD = +5V
T

= +258C

A

Figure 10. AD5302 INL and DNL
Error vs. V

REF

–0.6

2000

CODE

600400

800 1000

Figure 8. AD5312 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

–40 0 120

40 80

TEMPERATURE – 8C

Figure 11. AD5302 INL Error and
DNL Error vs. Temperature

–1.0

0 1000 40002000 3000

CODE

Figure 9. AD5322 Typical DNL Plot

1.0
VDD = +5V

V

= +2V

REF

0.5

GAIN ERROR

0.0

ERROR – %

–0.5

–1.0

–40 0 12040 80

OFFSET ERROR

TEMPERATURE – 8C

Figure 12. Offset Error and Gain
Error vs. Temperature

REV. 0

–7–

AD5302/AD5312/AD5322

V

LOGIC

– Volts

700

100

0 0.5 4.5

1.5 2.5 3.5

400

300

600

500

I

DD

– mA

1.0 2.0 3.0 4.0 5.0

200

TA = +258C

VDD = +5V

VDD = +3V

VDD = +5V

VDD = +3V

FREQUENCY

0

100 150 400200 250 350300

IDD – mA

Figure 13. IDD Histogram with VDD =
+3 V and V

600

500

400

300

– mA

DD

I

200

100

0

2.5

= +5 V

DD

BOTH DACS IN GAIN-OF-TWO MODE
REFERENCE INPUTS BUFFERED

+1058C

4.0

4.5

+258C

5.0

3.0

–408C

3.5
VDD – Volts

5.5

Figure 16. Supply Current vs. Supply
Voltage

5

5V SOURCE

4

3V SOURCE

5V SINK

23

3V SINK

456

3

– Volts

OUT

2

V

1

0

01

SINK/SOURCE CURRENT – mA

Figure 14. Source and Sink Current
Capability

1.0
BOTH DACS IN

THREE-STATE CONDITION

0.8

0.6

– mA

DD

I

0.4

0.2

0

2.7 3.2 5.2

3.7 4.2 4.7
VDD – Volts

–408C

+258C

+1058C

Figure 17. Power-Down Current vs.
Supply Voltage

600

500

400

– mA

300

DD

I

200

100

0

ZERO-SCALE FULL-SCALE

VDD = +5V

= +258C

T

A

Figure 15. Supply Current vs. Code

Figure 18. Supply Current vs. Logic
Input Voltage

CLK

CH2

CH1

V

OUT

CH1 1V, CH2 5V, TIME BASE = 5ms/DIV

Figure 19. Half-Scale Settling (1/4 to
3/4 Scale Code Change)

VDD = +5V
T

= +258C

A

TA = +258C

V

DD

CH1

CH2

CH1 1V, CH2 1V, TIME BASE = 20ms/DIV

V

A

OUT

Figure 20. Power-On Reset to 0 V

–8–

TA = +258C

V

OUT

CH1

CH3

CLK

CH1 1V, CH3 5V, TIME BASE = 1ms/DIV

Figure 21. Exiting Power-Down to
Midscale

REV. 0

AD5302/AD5312/AD5322

2.50

2.49

– Volts

OUT

V

2.48

2.47

Figure 22. AD5322 Major-Code
Transition

1.0
TA = +258C

= +5V

V

DD

0.5

0

10

0

–10

–20

dB

–30

–40

–50

–60

0.01

0.1 1 10 100 1k 10k
FREQUENCY – kHz

Figure 23. Multiplying Bandwidth
(Small-Signal Frequency Response)

2mV/DIV

500ns/DIV

Figure 24. DAC-DAC Crosstalk

–0.5

FULL-SCALE ERROR – Volts

–1.0

01 5234

V

– Volts

REF

Figure 25. Full-Scale Error vs. V
(Buffered)

REF

REV. 0

–9–

AD5302/AD5312/AD5322

GENERAL DESCRIPTION

The AD5302/AD5312/AD5322 are dual resistor string DACs
fabricated on a CMOS process with resolutions of 8, 10 and 12
bits, respectively. They contain reference buffers, output buffer
amplifiers and are written to via a 3-wire serial interface. They
operate from single supplies of +2.5 V to +5.5 V and the output
buffer amplifiers provide rail-to-rail output swing with a slew

rate of 0.7 V/µs. Each DAC is provided with a separate refer-

ence input, which may be buffered to draw virtually no current
from the reference source, or unbuffered to give a reference
input range from GND to V

. The devices have three program-

DD

mable power-down modes, in which one or both DACs may be
turned off completely with a high impedance output, or the
output may be pulled low by an on-chip resistor.

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 26 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:

VD

×

OUT

REF

=

N

2

V

where

D = decimal equivalent of the binary code that is loaded to the
DAC register;

0–255 for AD5302 (8 Bits)
0–1023 for AD5312 (10 Bits)
0–4095 for AD5322 (12 Bits).

N = DAC resolution.

V

A

REF

SWITCH
CONTROLLED
BY CONTROL
LOGIC

OUTPUT BUFFER

AMPLIFIER

A

V

OUT

INPUT

REGISTER

REFERENCE

DAC

REGISTER

BUFFER

RESISTOR

STRING

Figure 26. Single DAC Channel Architecture

Resistor String

The resistor string section is shown in Figure 27. 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.

R

R

R

R

R

TO OUTPUT
AMPLIFIER

Figure 27. Resistor String

DAC Reference Inputs

There is a reference input pin for each of the two DACs. The
reference inputs are buffered but can also be configured as un­buffered. The advantage with the buffered input is the high
impedance it presents to the voltage source driving it.

However, if the unbuffered mode is used, the user can have a
reference voltage as low as GND and as high as V

since there

DD

is no restriction due to headroom and foot room of the reference
amplifier.

If there is a buffered reference in the circuit (e.g., REF192)
there is no need to use the on-chip buffers of the AD5302/
AD5312/AD5322. In unbuffered mode the impedance is still

large (180 kΩ per reference input).

The buffered/unbuffered option is controlled by the BUF bit in
the control word (see Serial Interface section for a description of
the register contents).

Output Amplifier

The output buffer amplifier is capable of generating output
voltages to within 1 mV of either rail which gives an output
range of 0.001 V to V

– 0.001 V when the reference is VDD. It

DD

is capable of driving a load of 2 kΩ in parallel with 500 pF to

GND and V

. The source and sink capabilities of the output

DD

amplifier can be seen in Figure 14.

The slew rate is 0.7 V/µs with a half-scale settling time to
±0.5 LSB (at 8 bits) of 6 µs. See Figure 19.

POWER-ON RESET

The AD5302/AD5312/AD5322 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 inputs unbuffered.
– 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.

–10–

REV. 0

AD5302/AD5312/AD5322

SERIAL INTERFACE

The AD5302/AD5312/AD5322 are controlled over a versatile,
3-wire serial interface, which operates at clock rates up to 30 MHz
and is compatible with SPI, QSPI, MICROWIRE and DSP
interface standards.

Input Shift Register

The input shift register is 16 bits wide (see Figures 28–30 below).
Data is loaded into the device as a 16-bit word under the con­trol of a serial clock input, SCLK. The timing diagram for this
operation is shown in Figure 1. The 16-bit word consists of four
control bits followed by 8, 10 or 12 bits of DAC data, depend­ing on the device type. The first bit loaded is the MSB (Bit 15),
which determines whether the data is for DAC A or DAC B. Bit
14 determines if the reference input will be buffered or unbuf­fered. Bits 13 and 12 control the operating mode of the DAC.

Table I. Control Bits

Power-On

Bit Name Function Default

15 A/B 0: Data Written to DAC A N/A

1: Data Written to DAC B

14 BUF 0: Reference Is Unbuffered 0

1: Reference Is Buffered
13 PD1 Mode Bit 0
12 PD0 Mode Bit 0

DB0 (LSB)DB15 (MSB)

PD1PD0D7D6D5D4D3D2D1D0XXXX

BUF

A/B

DATA BITS

Figure 28. AD5302 Input Shift Register Contents

DB0 (LSB)DB15 (MSB)

PD1 PD0 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 X X

BUF

A/B

DATA BITS

Figure 29. AD5312 Input Shift Register Contents

DB0 (LSB)DB15 (MSB)

PD1 PD0 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

BUF

A/B

DATA BITS

Figure 30. AD5322 Input Shift Register Contents

The remaining bits are DAC data bits, starting with the MSB
and ending with the LSB. The AD5322 uses all 12 bits of DAC
data, the AD5312 uses 10 bits and ignores the 2 LSBs. The
AD5302 uses eight bits and ignores the last four bits. The data
format is straight binary, with all zeroes corresponding to
0 V output, and all ones corresponding to full-scale output

– 1 LSB).

(V

REF

The SYNC input is a level-triggered input that acts as a frame
synchronization signal and chip enable. Data can only be trans­ferred into the device while SYNC is low. To start the serial
data transfer, SYNC should be taken low observing the mini­mum SYNC to SCLK active edge setup time, t

. After SYNC

4

goes low, serial data will be shifted into the device’s input shift
register on the falling edges of SCLK for 16 clock pulses. Any
data and clock pulses after the 16th will be ignored, and no
further serial data transfer will occur until SYNC is taken high
and low again.

SYNC may be taken high after the falling edge of the 16th
SCLK pulse, observing the minimum SCLK falling edge to
SYNC rising edge time, t

.

7

After the end of serial data transfer, data will automatically be
transferred from the input shift register to the input register of
the selected DAC. If SYNC is taken high before the 16th falling
edge of SCLK, the data transfer will be aborted and the input
registers will not be updated.

When data has been transferred into both input registers, the
DAC registers of both DACs may be simultaneously updated,
by taking LDAC low.

Low Power Serial Interface

To reduce the power consumption of the device even further,
the interface only powers up fully when the device is being writ­ten to. As soon as the 16-bit control word has been written to
the part, the SCLK and DIN input buffers are powered down.
They only power-up again following a falling edge of SYNC.

Double-Buffered Interface

The AD5302/AD5312/AD5322 DACs all have double-buffered
interfaces consisting of two banks of registers—input registers
and DAC registers. The input register is connected directly to
the input shift register and the digital code is transferred to the
relevant input register on completion of a valid write sequence.
The DAC register contains the digital code used by the resistor
string.

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.

This is useful if the user requires simultaneous updating of both
DAC outputs. The user may write to both input registers indi­vidually and then, by pulsing the LDAC input low, both outputs
will update simultaneously.

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 registers are filled with the
contents of the input registers. In the case of the AD5302/AD5312/
AD5322, the part will only update the DAC register if the input
register has been changed since the last time the DAC register
was updated thereby removing unnecessary digital crosstalk.

REV. 0

–11–

AD5302/AD5312/AD5322

POWER-DOWN MODES

The AD5302/AD5312/AD5322 have very low power consump­tion, dissipating only 0.7 mW with a 3 V supply and 1.5 mW
with a 5 V supply. Power consumption can be further reduced
when the DACs are not in use by putting them into one of three
power-down modes, which are selected by Bits 13 and 12 (PD1
and PD0) of the control word. Table II shows how the state of
the bits corresponds to the mode of operation of that particular
DAC.

Table II. PD1/PD0 Operating Modes

PD1 PD0 Operating Mode

0 0 Normal Operation

0 1 Power-Down (1 kΩ Load to GND)
1 0 Power-Down (100 kΩ Load to GND)

1 1 Power-Down (High Impedance Output)

When both bits are set to 0, the DACs work normally with their

normal power consumption of 300 µA at 5 V. However, for the

three power-down modes, the supply current falls to 200 nA at
5 V (50 nA at 3 V). Not only does the supply current drop 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 part is known 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. There are three different options. The output is con-

nected internally to GND through a 1 kΩ resistor, a 100 kΩ

resistor or it is left open-circuited (Three-State). The output
stage is illustrated in Figure 31.

The bias generator, the output amplifier, the resistor string and
all other associated linear circuitry are all 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

V

= 3 V. See Figure 21 for a plot.

DD

RESISTOR

STRING DAC

AMPLIFIER

POWER-DOWN

CIRCUITRY

= 5 V and 5 µs when

DD

V

OUT

RESISTOR
NETWORK

MICROPROCESSOR INTERFACING
AD5302/AD5312/AD5322 to ADSP-2101/ADSP-2103 Interface

Figure 32 shows a serial interface between the AD5302/AD5312/
AD5322 and the ADSP-2101/ADSP-2103. The ADSP-2101/
ADSP-2103 should be set up to operate in the SPORT Trans­mit Alternate Framing Mode. The ADSP-2101/ADSP-2103
SPORT is programmed through the SPORT control register
and should be configured as follows: Internal Clock Operation,
Active Low Framing, 16-Bit Word Length. Transmission is
initiated by writing a word to the Tx register after the SPORT
has been enabled. The data is clocked out on each falling edge
of the DSP’s serial clock and clocked into the AD5302/AD5312/
AD5322 on the rising edge of the DSP’s serial clock. This corre­sponds to the falling edge of the DAC’s SCLK.

ADSP-2101/
ADSP-2103*

TFS

DT

SCLK

*ADDITIONAL PINS OMITTED FOR CLARITY.

AD5302/
AD5312/
AD5322*

SYNC

DIN
SCLK

Figure 32. AD5302/AD5312/AD5322 to ADSP-2101/ADSP­2103 Interface

AD5302/AD5312/AD5322 to 68HC11/68L11 Interface

Figure 33 shows a serial interface between the AD5302/AD5312/
AD5322 and the 68HC11/68L11 microcontroller. SCK of the
68HC11/68L11 drives the SCLK of the AD5302/AD5312/
AD5322, while the MOSI output drives the serial data line of
the DAC. The SYNC signal is derived from a port line (PC7).
The setup conditions for correct operation of this interface are
as follows: the 68HC11/68L11 should be configured so that its
CPOL bit is a 0 and its CPHA bit is a 1. When data is being
transmitted to the DAC, the SYNC line is taken low (PC7).
When the 68HC11/68L11 is configured as above, data appear­ing on the MOSI output is valid on the falling edge of SCK.
Serial data from the 68HC11/68L11 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 AD5302/AD5312/AD5322, PC7 is left low after the first
eight bits are transferred, and a second serial write operation is
performed to the DAC and PC7 is taken high at the end of this
procedure.

Figure 31. Output Stage During Power-Down

–12–

68HC11/68L11*

PC7

SCK

MOSI

*ADDITIONAL PINS OMITTED FOR CLARITY.

AD5302/
AD5312/

AD5322*

SYNC

SCLK
DIN

Figure 33. AD5302/AD5312/AD5322 to 68HC11/68L11
Interface

REV. 0

AD5302/AD5312/AD5322

AD5302/AD5312/AD5322 to 80C51/80L51 Interface

Figure 34 shows a serial interface between the AD5302/AD5312/
AD5322 and the 80C51/80L51 microcontroller. The setup for
the interface is as follows: TXD of the 80C51/80L51 drives
SCLK of the AD5302/AD5312/AD5322, while RXD drives the
serial data line of the part. The SYNC signal is again derived
from a bit programmable pin on the port. In this case port line
P3.3 is used. When data is to be transmitted to the AD5302/
AD5312/AD5322, P3.3 is taken low. The 80C51/80L51 trans­mits data only 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, and a second
write cycle is initiated to transmit the second byte of data. P3.3
is taken high following the completion of this cycle. The 80C51/
80L51 outputs the serial data in a format that has the LSB first.
The AD5302/AD5312/AD5322 requires its data with the MSB
as the first bit received. The 80C51/80L51 transmit routine
should take this into account.

80C51/80L51*

P3.3
TXD

RXD

AD5302/
AD5312/
AD5322*

SYNC

SCLK
DIN

APPLICATIONS INFORMATION
Typical Application Circuit

The AD5302/AD5312/AD5322 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 V to V

. More typically, the AD5302/AD5312/AD5322 may

DD

be used with a fixed, precision reference voltage. Figure 36
shows a typical setup for the AD5302/AD5312/AD5322 when
using an external reference. If the reference inputs are unbuf­fered, the reference input range is from 0 V to V

, but if the

DD

on-chip reference buffers are used, the reference range is reduced.
Suitable references for 5 V operation are the AD780 and REF192
(2.5 V references). For 2.5 V operation, a suitable external
reference would be the REF191, a 2.048 V reference.

VDD = +2.5V TO +5.5V

V

EXT

V

OUT

REF

AD780/REF192

WITH V

= +5V

DD

OR REF191 WITH

= +2.5V

V

DD

1mF

V
V

AD5302/AD5312/

SCLK
DIN

SYNC

REF
REF

A
B

DD

AD5322

GND

V

A

OUT

B

V

OUT

*ADDITIONAL PINS OMITTED FOR CLARITY.

Figure 34. AD5302/AD5312/AD5322 to 80C51/80L51
Interface

AD5302/AD5312/AD5322 to MICROWIRE Interface

Figure 35 shows an interface between the AD5302/AD5312/
AD5322 and any MICROWIRE-compatible device. Serial data
is shifted out on the falling edge of the serial clock and is
clocked into the AD5302/AD5312/AD5322 on the rising edge
of the SK.

MICROWIRE*

CS
SK
SO

*ADDITIONAL PINS OMITTED FOR CLARITY.

AD5302/
AD5312/

AD5322*

SYNC

SCLK
DIN

Figure 35. AD5302/AD5312/AD5322 to MICROWIRE
Interface

SERIAL

INTERFACE

Figure 36.␣ AD5302/AD5312/AD5322 Using External
Reference

If an output range of 0 V to VDD is required when the reference
inputs are configured as unbuffered (for example 0 V to +5 V),
the simplest solution is to connect the reference inputs to V

DD

.
As this supply may not be very accurate and may be noisy, the
AD5302/AD5312/AD5322 may be powered from the reference
voltage; for example, using a 5 V reference such as the REF195,
as shown in Figure 37. The REF195 will output a steady supply
voltage for the AD5302/AD5312/AD5322 The current required

from the REF195 is 300 µA supply current and approximately
30 µA into each of the reference inputs. This is with no load on

the DAC outputs. When the DAC outputs are loaded, the
REF195 also needs to supply the current to the loads. The total

current required (with a 10 kΩ load on each output) is:

360 µA + 2(5 V/10 kΩ) = 1.36 mA

The load regulation of the REF195 is typically 2 ppm/mA which

results in an error of 2.7 ppm (13.5 µV) for the 1.36 mA current

drawn from it. This corresponds to a 0.0007 LSB error at 8-bits
and 0.011 LSB error at 12 bits.

REV. 0

–13–

AD5302/AD5312/AD5322

+6V TO +16V

V

IN

REF195

V

OUT

GND

0.1mF 10mF

1mF

V

DD

V

A

REF

V

B

REF

A

V

OUT

AD5302/AD5312/

AD5322

SERIAL

INTERFACE

SCLK
DIN

SYNC

GND

V

B

OUT

Figure 37. Using an REF195 as Power and Reference to
the AD5302/AD5312/AD5322

Bipolar Operation Using the AD5302/AD5312/AD5322

The AD5302/AD5312/AD5322 has been designed for single
supply operation, but bipolar operation is also achievable using
the circuit shown in Figure 38. The circuit shown has been config­ured to achieve an output voltage range of –5␣ V < V

OUT

< +5 V.
Rail-to-rail operation at the amplifier output is achievable using
an AD820 or OP295 as the output amplifier.

+6V TO +16V

V

IN

REF

V

OUT

195

GND

0.1mF

1mF

SERIAL

INTERFACE

VDD = +5V

10mF

V

DD

V

A/B

REF

AD5302/AD5312/

AD5322

SCLK
DIN

SYNC

GND

V

10kV

OUT

R2

10kV

R1

A/B

+5V

–5V

AD820/
OP295

65V

Figure 38. Bipolar Operation Using the AD5302/AD5312/
AD5322

The output voltage for any input code can be calculated as
follows:

V

OUT

= [(V

× D/2N) × (R1+R2)/R1 – V

REF

× (R2/R1)]

REF

where

D is the decimal equivalent of the code loaded to the DAC
N is the DAC resolution

V

is the reference voltage input.

REF

with

V

= 5 V

REF

R1 = R2 = 10 kΩ and V

V

= (10 × D/2

OUT

DD

N

) – 5 V

= 5 V

Opto-Isolated Interface for Process Control Applications

The AD5302/AD5312/AD5322 has a versatile 3-wire serial
interface, making it ideal for generating accurate voltages in
process control and industrial applications. Due to noise, safety
requirements or distance, it may be necessary to isolate the
AD5302/AD5312/AD5322 from the controller. This can easily
be achieved by using opto-isolators, which will provide isolation
in excess of 3 kV. The serial loading structure of the AD5302/
AD5312/AD5322 makes it ideally suited for use in opto-isolated
applications. Figure 39 shows an opto-isolated interface to the
AD5302/AD5312/AD5322 where DIN, SCLK and SYNC are
driven from opto-couplers. The power supply to the part also
needs to be isolated. This is done by using a transformer. On
the DAC side of the transformer, a +5 V regulator provides the
+5 V supply required for the AD5302/AD5312/AD5322.

+5V

POWER

SCLK

SYNC

DIN

REGULATOR

V

10kV

V

10kV

V

10kV

DD

SCLK

AD5302/AD5312/

DD

SYNC

DD

DIN

GND

AD5322

10mF

0.1mF

V

DD

V

A

REF

V

B

REF

A

V

OUT

V

B

OUT

Figure 39. AD5302/AD5312/AD5322 in an Opto-Isolated
Interface

–14–

REV. 0

AD5302/AD5312/AD5322

Decoding Multiple AD5302/AD5312/AD5322s

The SYNC pin on the AD5302/AD5312/AD5322 can be used
in applications to decode a number of DACs. In this applica­tion, all the DACs in the system receive the same serial clock
and serial data, but only the SYNC to one of the devices will be
active at any one time allowing access to two channels in this
eight-channel system. The 74HC139 is used as a 2-to-4 line
decoder to address any of the DACs in the system. To prevent
timing errors from occurring, the enable input should be brought
to its inactive state while the coded address inputs are changing
state. Figure 40 shows a diagram of a typical setup for decoding
multiple AD5302/AD5312/AD5322 devices in a system.

SCLK

DIN

ENABLE

CODED

ADDRESS

1G
1A
1B

V

DD

V

CC

74HC139

DGND

1Y0
1Y1
1Y2
1Y3

AD5302/AD5312/AD5322

SYNC

DIN
SCLK

AD5302/AD5312/AD5322

SYNC

DIN
SCLK

AD5302/AD5312/AD5322

SYNC

DIN
SCLK

AD5302/AD5312/AD5322

SYNC

DIN
SCLK

Figure 40. Decoding Multiple AD5302/AD5312/AD5322
Devices in a System

AD5302/AD5312/AD5322 as a Digitally Programmable
Window Detector

A digitally programmable upper/lower limit detector using the
two DACs in the AD5302/AD5312/AD5322 is shown in Figure

41. The upper and lower limits for the test are loaded to DACs
A and B which, in turn, set the limits on the CMP04. If the
signal at the V

input is not within the programmed window,

IN

an LED will indicate the fail condition.

+5V

V

REF

SYNC

DIN

SCLK

0.1mF 10mF

V

A

REF

B

V

REF

V

AD5302/AD5312/

AD5322

SYNC

DIN
SCLK

GND

V

IN

DD

V

A

OUT

1/2

CMP04

B

V

OUT

1kV

FAIL

PASS/FAIL

1/6 74HC05

1kV

PASS

Figure 41. Window Detector Using AD5302/AD5312/AD5322

Coarse and Fine Adjustment Using the AD5302/AD5312/
AD5322

The DACs in the AD5302/AD5312/AD5322 can be paired
together to form a coarse and fine adjustment function, as
shown in Figure 42. DAC A is used to provide the coarse ad­justment while DAC B provides the fine adjustment. Varying
the ratio of R1 and R2 will change the relative effect of the
coarse and fine adjustments. With the resistor values and exter­nal reference shown, the output amplifier has unity gain for the
DAC A output, so the output range is 0 V to 2.5 V – 1 LSB. For

DAC B the amplifier has a gain of 7.6 × 10

–3

, giving DAC B a

range equal to 19 mV.

The circuit is shown with a 2.5 V reference, but reference volt­ages up to V

may be used. The op amps indicated will allow a

DD

rail-to-rail output swing.

V

IN

EXT

V

OUT

REF

GND

AD780/REF192

WITH V

= +5V

DD

0.1mF 10mF

V

1mF

REF

AD5302/AD5312/

V

REF

VDD = +5V

V

DD

A

AD5322

B

GND

R3

51.2kV

R1

390V

V

A

OUT

R2

51.2kV

V

B

OUT

R4

390V

+5V

AD820/
OP295

V

OUT

Figure 42. Coarse/Fine Adjustment

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
AD5302/AD5312/AD5322 is mounted should be designed so
that the analog and digital sections are separated, and confined
to certain areas of the board. If the AD5302/AD5312/AD5322
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 close as possible
to the AD5302/AD5312/AD5322. The AD5302/AD5312/

AD5322 should have ample supply bypassing of 10 µF in paral-
lel with 0.1 µF on the supply located as close to the package as
possible, ideally right up against the device. The 10 µF capaci-
tors 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 AD5302/AD5312/AD5322 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 double­sided board. In this technique, the component side of the board
is dedicated to ground plane while signal traces are placed on
the solder side.

REV. 0

–15–

AD5302/AD5312/AD5322

OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

10-Lead ␮SOIC

(RM-10)

0.122 (3.10)

0.114 (2.90)

0.122 (3.10)

0.114 (2.90)

0.037 (0.94)

0.031 (0.78)

0.006 (0.15)

0.002 (0.05)

10 6

PIN 1

0.0197 (0.50) BSC

0.120 (3.05)

0.112 (2.85)

51

0.012 (0.30)

0.006 (0.15)

0.199 (5.05)

0.187 (4.75)

0.043 (1.10)
MAX

SEATING
PLANE

0.009 (0.23)

0.005 (0.13)

0.120 (3.05)

0.112 (2.85)

68
08

C3447–8–3/99

0.028 (0.70)

0.016 (0.40)

–16–

PRINTED IN U.S.A.

REV. 0