AD7248AAQ AD [Analog Devices], AD7248AAQ Datasheet

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AD7248AAQ

Manufacturer Part Number
AD7248AAQ
Description
LC2MOS 12-Bit DACPORTs
Manufacturer
AD [Analog Devices]
Datasheet
a
GENERAL DESCRIPTION
The AD7245A/AD7248A is an enhanced version of the industry
standard AD7245/AD7248. Improvements include operation
from 12 V to 15 V supplies, a 1/2 LSB linearity grade, faster
interface times and better full scale and reference variations with
V
operation for commercial and industrial grades.
The AD7245A/AD7248A is a complete, 12-bit, voltage output,
digital-to-analog converter with output amplifier and Zener volt-
age reference on a monolithic CMOS chip. No external user
trims are required to achieve full specified performance.
Both parts are microprocessor compatible, with high speed data
latches and double-buffered interface logic. The AD7245A ac-
cepts 12-bit parallel data which is loaded into the input latch on
the rising edge of CS or WR. The AD7248A has an 8-bit wide
data bus with data loaded to the input latch in two write opera-
tions. For both parts, an asynchronous LDAC signal transfers
data from the input latch to the DAC latch and updates the ana-
log output. The AD7245A also has a CLR signal on the DAC latch
which allows features such as power-on reset to be implemented.
The on-chip 5 V buried Zener diode provides a low noise, tem-
perature compensated reference for the DAC. For single supply
operation, two output ranges of 0 V to +5 V and 0 V to +10 V
are available, while these two ranges plus an additional 5 V
range are available with dual supplies. The output amplifiers are
capable of developing +10 V across a 2 k load to GND.
The AD7245A/AD7248A is fabricated in linear compatible
CMOS (LC
combines precision bipolar circuits with low power CMOS logic.
The AD7245A is available in a small, 0.3" wide, 24-pin DIP and
DACPORT is a registered trademark of Analog Devices, Inc.
REV. A
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.
DD
FEATURES
12-Bit CMOS DAC with Output Amplifier and
Improved AD7245/AD7248:
Extended Plastic Temperature Range (–40 C to +85 C)
Single or Dual Supply Operation
Low Power–65 mW typ in Single Supply
Parallel Loading Structure: AD7245A
(8+4) Loading Structure: AD7248A
. Additional features include extended temperature range
Reference
12 V to 15 V Operation
Faster Interface–30 ns typ Data Setup Time
1/2 LSB Linearity Grade
2
MOS), an advanced, mixed technology process that
SOIC and in 28-terminal surface mount packages. The
AD7248A is packaged in a small, 0.3" wide, 20-pin DIP and
SOIC and in 20-terminal surface mount packages.
PRODUCT HIGHLIGHTS
1. The AD7245A/AD7248A is a 12-bit DACPORT
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700
2. The improved interface times on the part allows easy, direct
3. The AD7245A/AD7248A features a wide power supply range
chip. This single chip design and small package size offer
considerable space saving and increased reliability over
multichip designs.
interfacing to most modern microprocessors.
allowing operation from 12 V supplies.
AD7245A FUNCTIONAL BLOCK DIAGRAM
AD7248A FUNCTIONAL BLOCK DIAGRAM
AD7245A/AD7248A
12-Bit DACPORTs
Fax: 617/326-8703
LC
®
on a single
2
MOS

Related parts for AD7248AAQ

AD7248AAQ Summary of contents

Page 1

FEATURES 12-Bit CMOS DAC with Output Amplifier and Reference Improved AD7245/AD7248 Operation 1/2 LSB Linearity Grade Faster Interface–30 ns typ Data Setup Time Extended Plastic Temperature Range (– +85 C) Single or ...

Page 2

AD7245A/AD7248A–SPECIFICATIONS AGND = DGND = 1OO pF. All specifications Parameter STATIC PERFORMANCE Resolution 3 Relative Accuracy @ + MIN MAX MIN ...

Page 3

SWITCHING CHARACTERISTICS Parameter A, B Versions + MIN MAX + MIN MAX + ...

Page 4

... This grade will be available to /883B processing only. AD7248A ORDERING GUIDE Temperature l Model Range AD7248AAN – +85 C AD7248ABN – +85 C AD7248AAQ – + AD7248ATQ – +125 C AD7248AAP – +85 C AD7248AAR – +85 C AD7248ABR – +85 C NOTES 1 To order MIL-STD-883, Class B, processed parts, add /883B to part number ...

Page 5

Pin Mnemonic Description l V Negative Supply Voltage (0 V for single SS supply operation Bipolar Offset Resistor. This provides OFS access to the on-chip application resistors and allows different output voltage ranges. 3 REF OUT Reference Output. ...

Page 6

AD7245A/AD7248A Pin Mnemonic Description l V Negative Supply Voltage (0 V for single SS supply operation Bipolar Offset Resistor. This provides OFS access to the on-chip application resistors and allows different output voltage ranges. 3 REF OUT Reference ...

Page 7

Power Supply Current vs. Temperature Noise Spectral Density vs. Frequency Positive-Going Settling Time ( – REV. A Typical Performance–AD7245A/AD7248A Reference Voltage vs. Temperature Power Supply Rejection Ration vs. Frequency Negative Going Settling ...

Page 8

AD7245A/AD7248A CIRCUIT INFORMATION D/A SECTION The AD7245A/AD7248A contains a 12-bit voltage mode digi- tal-to-analog converter. The output voltage from the converter has the same positive polarity as the reference voltage allowing single supply operation. The reference voltage for the DAC ...

Page 9

The data held in the DAC latch determines the analog output of the converter. Data is latched into the DAC latch on the rising edge of LDAC. This LDAC signal is an asynchronous signal and is independent of WR. This ...

Page 10

AD7245A/AD7248A the simultaneous updating of multiple AD7248A outputs. How- ever, in systems where the asynchronous LDAC can occur dur- ing a write cycle (or vice versa) care must be taken to ensure that incorrect data is not latched through to ...

Page 11

BIPOLAR CONFIGURATION The bipolar configuration for the AD7245A/AD7248A, which gives an output voltage range from – achieved by connecting the R input to REF OUT and connecting R OFS and V . The AD7245A/AD7248A must ...

Page 12

AD7245A/AD7248A The circuit of Figure 10 can be modified to provide a program- mable current source to AGND or –V SINK plies are required on the AD7245A/AD7248A). The AD7245A/ AD7248A is configured as before. The current through R1 is mirrored ...

Page 13

In a multiple DAC system the double buffering of the AD7245A allows the user to simultaneously update all DACs. In Figure 13, a 12-bit word is loaded to the input latches of each of the DACs in sequence. Then, with ...

Page 14

AD7245A/AD7248A Figure 16. AD7248A to 68008 Interface An interface circuit for connections to the 6502 or 6809 micro- processors is shown in Figure 17. Once again, the AD7248A is memory mapped and data is right justified. The procedure for writing ...

Page 15

SOIC (R-24) Package 28-Terminal Leadless Ceramic Chip Carrier (E-28A) REV. A MECHANICAL INFORMATION—AD7245A OUTLINE DIMENSIONS Dimensions shown in inches and (mm). 24-Pin Plastic DIP (N-24) –15– AD7245A/AD7248A 24-Pin Cerdip (Q-24) 28-Terminal Plastic Leaded Chip Carrier (P-28A) ...

Page 16

AD7245A/AD7248A 20-Lead SOIC (R-20) MECHANICAL INFORMATION —AD7248A OUTLINE DIMENSIONS Dimensions shown in inches and (mm). 20-Pin Plastic DIP (N-20) 20-Pin Cerdip (Q-20) –16– 20-Terminal Plastic Leaded Chip Carrier (P-20A) REV. A ...

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