AD7228A Analog Devices, AD7228A Datasheet - Page 4

• Manufacturer Part Number: AD7228A
• Description: LC2MOS Octal 8-Bit DAC
• Manufacturer: Analog Devices

AD7228A
ABSOLUTE MAXIMUM RATINGS
V
V
Digital Input Voltage to GND . . . . . . . . . . . . . . . –0.3 V, V
V
V
Power Dissipation (Any Package) to +75 C . . . . . . . 1000 mW
Operating Temperature
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 AD7228A 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.
Model
AD7228ABN
AD7228ACN
AD7228ABP
AD7228ACP
AD7228ABR
AD7228ACR
AD7228ABQ
AD7228ACQ
AD7228ATQ
AD7228AUQ
NOTES
1
2
3
To order MIL-STD-883, Class B processed parts, add /883B to part number.
N = Plastic DIP; P = Plastic Leaded Chip Carrier (PLCC); Q = Cerdip;
These grades will be available to /883B processing only.
Contact your local sales office for military data sheet and availability.
R = Small Outline IC (SOIC).
DD
DD
REF
OUT
Derates above 75 C by . . . . . . . . . . . . . . . . . . . . 2.0 mW/ C
Commercial . . . . . . . . . . . . . . . . . . . . . . . . –40 C to +85 C
Industrial . . . . . . . . . . . . . . . . . . . . . . . . . . –40 C to +85 C
to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V, +17 V
to V
to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3V, V
DIP AND SOIC
to GND
1
SS
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V, +24 V
3
3
2
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V
Temperature
Range
–40 C to +85 C
–40 C to +85 C
–40 C to +85 C
–40 C to +85 C
–40 C to +85 C
–40 C to +85 C
–40 C to +85 C
–40 C to +85 C
–55 C to +125 C
–55 C to +125 C
PIN CONFIGURATIONS
ORDERING GUIDE
1
Total
Unadjusted
Error (LSB) Option
2 max
1 max
2 max
1 max
2 max
1 max
2 max
1 max
2 max
1 max
PLCC
Package
N-24
N-24
P-28A
P-28A
R-24
R-24
Q-24
Q-24
Q-24
Q-24
SS
, V
DD
DD
DD
2
–4–
Storage Temperature . . . . . . . . . . . . . . . . . . –65 C to +150 C
Lead Temperature (Soldering, 10 secs) . . . . . . . . . . . +300 C
NOTES
1
2
CIRCUIT INFORMATION
D/A SECTION
The AD7228A contains eight identical, 8-bit, voltage-mode
digital-to-analog converters. The output voltages from the con-
verters have the same polarity as the reference voltage, allowing
single supply operation. A novel DAC switch pair arrangement
on the AD7228A allows a reference voltage range from +2 V to
+10 V when operated from a V
of a highly stable, thin-film, R-2R ladder and eight high-speed
NMOS switches. The simplified circuit diagram for one channel
is shown in Figure 3. Note that V
all eight DACs.
The input impedance at the V
parallel combination of the eight individual DAC reference in-
put impedances. It is code dependent and can vary from 2 k to
infinity. The lowest input impedance occurs when all eight
DACs are loaded with digital code 01010101. Therefore, it is
important that the external reference source presents a low out-
put impedance to the V
changing load conditions. Due to transient currents at the refer-
ence input during digital code changes a 0.1 F (or greater)
decoupling capacitor is recommended on the V
applications. The nodal capacitance at the reference terminal is
also code dependent and typically varies from 120 pF to
350 pF.
Each V
voltage source with an output voltage:
The output impedance is that of the output buffer amplifier as
described in the following section.
Stresses above those listed under “Absolute Maximum Ratings” may cause
permanent damage to the device. This is a stress rating only and functional
operation of the device at these or any other conditions above those indicated in the
operational sections of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
Outputs may be shorted to any voltage in the range V
power dissipation of the package is not exceeded. Typical short circuit current for
a short to GND or V
Extended . . . . . . . . . . . . . . . . . . . . . . . . . –55 C to +125 C
V
where D
code and can vary from 0 to 255/256.
OUTN
OUT
= D
Figure 3. D/A Simplified Circuit Diagram
N
pin can be considered as a digitally programmable
N
is a fractional representation of the digital input
• V
SS
REF
is 50 mA.
REF
terminal of the AD7228A under
REF
DD
REF
pin of the AD7228A is the
WARNING!
of +15 V. Each DAC consists
and GND are common to
SS
to V
ESD SENSITIVE DEVICE
REF
DD
provided that the
input for dc
REV. A