AD8842 Analog Devices, AD8842 Datasheet

no-image

AD8842

Manufacturer Part Number
AD8842
Description
8-Bit Octal, 4-Quadrant Multiplying, CMOS TrimDAC
Manufacturer
Analog Devices
Datasheet

Specifications of AD8842

Resolution (bits)
8bit
Dac Update Rate
500kSPS
Dac Settling Time
2.9µs
Max Pos Supply (v)
+5.25V
Single-supply
No
Dac Type
Voltage Out
Dac Input Format
Ser,SPI

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
AD8842A
Manufacturer:
ADI
Quantity:
717
Part Number:
AD8842A
Manufacturer:
AD
Quantity:
1 000
Part Number:
AD8842AN
Manufacturer:
FUJ
Quantity:
6 225
Part Number:
AD8842AN
Manufacturer:
ADI/亚德诺
Quantity:
20 000
Part Number:
AD8842ANZ
Manufacturer:
ADI/亚德诺
Quantity:
20 000
Part Number:
AD8842AR
Manufacturer:
INTEL
Quantity:
6 000
Part Number:
AD8842AR
Manufacturer:
AD
Quantity:
20 000
Part Number:
AD8842ARZ
Manufacturer:
ADI/亚德诺
Quantity:
20 000
Part Number:
AD8842JR
Manufacturer:
ADI/亚德诺
Quantity:
20 000
a
GENERAL DESCRIPTION
The AD8842 provides eight general purpose digitally controlled
voltage adjustment devices. The TrimDAC® capability allows
replacement of the mechanical trimmer function in new designs.
The AD8842 is ideal for ac or dc gain control of up to 50 kHz
bandwidth signals. The four-quadrant multiplying capability is
useful for signal inversion and modulation often found in video
vertical deflection circuitry.
Internally the AD8842 contains eight voltage output digital-to-
analog converters, each with separate voltage inputs. A new
current conveyor amplifier design performs the four-quadrant
multiplying function with a single amplifier at the output of the
current steering digital-to-analog converter. This approach of-
fers an improved constant input resistance performance versus
previous voltage switched DACs used in TrimDAC circuits,
eliminating the need for additional input buffer amplifiers.
Each DAC has its own DAC register that holds its output state.
These DAC registers are updated from an internal serial-to-
parallel shift register that is loaded from a standard 3-wire serial
input digital interface. Twelve data bits make up the data word
clocked into the serial input register. This data word is decoded
where the first 4 bits determine the address of the DAC register
to be loaded with the last 8 bits of data. A serial data output pin
at the opposite end of the serial register allows simple daisy
chaining in multiple DAC applications without additional exter-
nal decoding logic.
TrimDAC is a registered trademark of Analog Devices, Inc.
The current conveyor amplifier is a patented circuit belonging to Analog
Devices, Inc.
REV.
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.
FEATURES
Low Cost
Replaces 8 Potentiometers
50 kHz 4-Quadrant Multiplying Bandwidth
Low Zero Output Error
Eight Individual Channels
3-Wire Serial Input
500 kHz Update Data Loading Rate
Midscale Preset, Zero Volts Out
APPLICATIONS
Automatic Adjustment
Trimmer Replacement
Vertical Deflection Amplitude Adjustment
Waveform Generation and Modulation
3 V Output Swing
A
The AD8842 consumes only 95 mW from 5 V power supplies.
For single 5 V supply applications consult the DAC-8841. The
AD8842 is pin compatible with the 1 MHz multiplying band-
width DAC8840. The AD8842 is available in 24-pin plastic
DIP and surface mount SOL-24 packages.
One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A.
Tel:
Figure 2. Actual Current Conveyor Implementation of
Multiplying DAC Channel
Figure 1. Functional Circuit of One 4-Quadrant
Multiplying Channel
781/329-4700
CLK
V
SDI
LD
DD
V
V
IN
Multiplying, CMOS TrimDAC
IN
8
4
GND
LOGIC
FUNCTIONAL BLOCK DIAGRAM
REGISTER
DECODED
ADDRESS
R
SERIAL
REF
8-Bit Octal, 4-Quadrant
8
DATA
256
D
SDO
(1- D)
256
R
V
8 X 8
R
DAC
IN
PR
R
G
R
E
S
T
E
S
I
V
R
IN
V
I1
I2
8
8
OUT
CURRENT CONVEYOR
= V
R
DAC A
DAC H
AMPLIFIER
IN
• (D/128 – 1)
AD8842
R
AD8842
Fax:
= V
V
V
OUT
IN
G
G
SS
781/461-3113
V
OUT
(D/128–1)
V
V
V
V
IN
OUT
IN
OUT
A
H
A
H

Related parts for AD8842

AD8842 Summary of contents

Page 1

... The AD8842 provides eight general purpose digitally controlled voltage adjustment devices. The TrimDAC® capability allows replacement of the mechanical trimmer function in new designs. The AD8842 is ideal for gain control kHz bandwidth signals. The four-quadrant multiplying capability is useful for signal inversion and modulation often found in video vertical deflection circuitry ...

Page 2

... AD8842–SPECIFICATIONS ELECTRICAL CHARACTERISTICS Parameter Symbol STATIC ACCURACY—All Specifications Apply for DACs Resolution N Integral Nonlinearity Error INL Differential Nonlinearity DNL Full-Scale Gain Error G Output Offset V Output Offset Drift TCV VOLTAGE INPUTS—Applies to All Inputs V 1 Input Voltage Range ...

Page 3

... 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 AD8842 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 ...

Page 4

... V D OUT OUT OUT OUT SDI AD8842 GND TOP VIEW SDO (Not to Scale CLK OUT ...

Page 5

... No Operation Shift One Bit in from SDI (Pin 20), Shift One Bit* Out from SDO (Pin 18) All DAC Registers = 80 H Load Serial Register Data into DAC(X) Register Serial Data Input Register Loading Disabled –5– AD8842 DAC UPDATED NO OPERATION DAC A DAC B DAC C DAC D ...

Page 6

... AD8842–Typical Performance Characteristics +1/2 DACs SUPERIMPOSED 0 – – +3V IN +1/2 0 DACs SUPERIMPOSED –1 128 192 256 DIGITAL INPUT CODE – Decimal Figure 4. Linearity Error vs. Digital Code + AVG +2 19 AVG 18 AVG – ...

Page 7

... IN Lower Trace 500ns Figure 17. Digital Feedthrough— mV/Div Code 7F OUT 50ns @ 5 mV/Div Figure 18. Clock Feedthrough—V –7– AD8842 5V 100 V/Div OUT 10mV 100 50ns @ 10 mV/Div, OUT 100 ...

Page 8

... AD8842 2V 100 Figure 19. 10 kHz Sawtooth Waveform, Upper Trace V , Lower Trace V IN –3dB FREQUENCY 300 200 100 0 –100 –200 500 mVp-p INPUT AMPLITUDE –300 –400 FREQUENCY – MHz Figure 21. AC Sweep Frequency 500 mV p-p Amplitude Response 100mV ...

Page 9

... CIRCUIT OPERATION The AD8842 is a general purpose 8-channel signal- level adjustment device designed to replace potentiometers used in the three-terminal connection mode. Eight independent channels of programmable signal level control are available in this 24-pin package device. The outputs are completely buffered providing output drive-current to drive external loads ...

Page 10

... Comments ( DIGITAL INTERFACING The four digital input pins (CLK, SDI, LD, PR) of the AD8842 Inverted FS were designed for TTL and 5 V CMOS logic compatibility. The SDO output pin offers good fanout in CMOS logic applications and can easily drive several AD8842s. ...

Page 11

... The digital feedthrough and crosstalk photographs shown in the typical performance characteristics section display these characteristics (Figures 15 and 17). A REV. Figure 32 shows a three-wire interface for a single AD8842 that LD easily cascades for multiple packages. This circuit topology often AD8842 CLK called daisy chaining requires preformating all the serial data for #1 each package in the chain ...

Page 12

... AD8842 OUTLINE DIMENSIONS 0.210 (5.33) MAX 0.150 (3.81) 0.130 (3.30) 0.115 (2.92) 0.022 (0.56) 0.018 (0.46) 0.014 (0.36) 0.30 (0.0118) 0.10 (0.0039) COPLANARITY 0.10 1.280 (32.51) 1.250 (31.75) 1.230 (31.24 0.280 (7.11) 0.250 (6.35) 1 0.240 (6.10) 12 0.100 (2.54) BSC 0.060 (1.52) 0.015 (0.38) 0.015 (0.38) MIN GAUGE SEATING PLANE 0.005 (0.13) MIN 0.070 (1.78) 0.060 (1.52) 0.045 (1.14) COMPLIANT TO JEDEC STANDARDS MS-001 CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS (IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN ...

Page 13

... AD8842ANZ −40°C to +85°C AD8842AR −40°C to +85°C AD8842AR-REEL −40°C to +85°C AD8842ARZ −40°C to +85°C AD8842ARZ-REEL −40°C to +85° RoHS Compliant Part. REVISION HISTORY 10/11—Rev Rev. A Changes to Pin 13 Mnemonic ......................................................... 4 Updated Outline Dimensions ....................................................... 12 Changes to Ordering Guide .......................................................... 13 4/94— ...

Related keywords