a
+3.3 V to +5 V Quad/Octal 10-Bit DACs
AD7804/AD7805/AD7808/AD7809
FUNCTIONAL BLOCK DIAGRAMS
FEATURES
Four 10-Bit DACs in One Package
Serial and Parallel Loading Facilities Available
AD7804 Quad 10-Bit Serial Loading
AD7805 Quad 10-Bit Parallel Loading
AD7808 Octal 10-Bit Serial Loading
AD7809 Octal 10-Bit Parallel Loading
+3.3 V to +5 V Operation
Power-Down Mode
Power-On Reset
Standby Mode (All DACs/Individual DACs)
Low Power All CMOS Construction
10-Bit Resolution
Double Buffered DAC Registers
Dual External Reference Capability
AVDD DVDD
REFOUT
1.23V REF
AGND DGND
VOUTF*
POWER ON
RESET
AD7804/
AD7808
REFIN
AVDD
DIVIDER
MUX
VBIAS
DAC D
COMP
CHANNEL D
CONTROL REG
DATA
REGISTER
MUX
CHANNEL C
CONTROL REG
VBIAS
DAC C
DATA
REGISTER
DAC B
DATA
REGISTER
CHANNEL A
CONTROL REG
VBIAS
DAC A
The AD7804/AD7808 are quad/octal 10-bit digital-to-analog
converters, with serial load capabilities, while the AD7805/AD7809
are quad/octal 10-bit digital-to-analog converters with parallel
load capabilities. These parts operate from a +3.3 V to +5 V
(±10%) power supply and incorporates an on-chip reference.
These DACs provide output signals in the form of VBIAS ± VSWING.
VSWING is derived internally from VBIAS. On-chip control registers
include a system control register and channel control registers.
The system control register has control over all DACs in the
package. The channel control registers allow individual control
of DACs. The complete transfer function of each individual
DAC can be shifted around the VBIAS point using an on-chip
Sub DAC. All DACs contain double buffered data inputs,
which allow all analog outputs to be simultaneously updated
using the asynchronous LDAC input.
FSIN
CLKIN
SDIN
VOUTH*
VOUTG*
INPUT SHIFT
REGISTER &
CONTROL LOGIC
CLR LDAC
**ONLY AD7804 SHOWN FOR CLARITY
**SHOWS ADDITIONAL CHANNELS ON THE AD7808
**PIN ON THE AD7808 ONLY
AVDD DVDD
REFOUT
1.23V REF
AGND DGND
VOUTF*
POWER ON
RESET
AD7805/
AD7809
REFIN
AVDD
DIVIDER
MUX
VBIAS
DAC D
Channels Controlled
Main DAC
All
͙
CHANNEL D
CONTROL REG
DATA
REGISTER
MUX
CHANNEL C
CONTROL REG
͙
͙
͙
͙
VBIAS
DAC C
DATA
REGISTER
͙
͙
Selective
Selective
Selective
͙
͙
͙
͙
DAC
REGISTER
VOUTC
DAC
REGISTER
VBIAS
͙
All
All
All
All
VOUTD
DAC B
VOUTB
Sub DAC
Hardware Clear
System Control
Power Down1
System Standby2
System Clear
Input Coding
Channel Control
Channel Standby2
Channel Clear
VBIAS
VOUTE*
COMP
MUX
Control Features
VOUTA
DAC
REGISTER
DATA
REGISTER
SYSTEM
CONTROL REG
GENERAL DESCRIPTION
VOUTB
DAC
REGISTER
MUX
PD**
VOUTC
DAC
REGISTER
VBIAS
CHANNEL B
CONTROL REG
VOUTD
DAC
REGISTER
MUX
APPLICATIONS
Optical Disk Drives
Instrumentation and Communication Systems
Process Control and Voltage Setpoint Control
Trim Potentiometer Replacement
Automatic Calibration
VOUTE*
͙
CHANNEL B
CONTROL REG
DATA
REGISTER
DAC
REGISTER
VBIAS
MUX
PD**
CHANNEL A
CONTROL REG
DAC A
DATA
REGISTER
DAC
REGISTER
SYSTEM
CONTROL REG
CS
WR
CONTROL
LOGIC
VOUTA
VOUTH*
INPUT
REGISTER
VOUTG*
͙
NOTES
1
Power-down function powers down all internal circuitry including the reference.
2
Standby functions power down all circuitry except for the reference.
MODE A0 A1 A2**
DB9 DB2 DB1 DB0
CLR LDAC
**ONLY AD7805 SHOWN FOR CLARITY
**SHOWS ADDITIONAL CHANNELS ON THE AD7809
**PIN ON THE AD7809 ONLY
REV. A
Index on Page 26.
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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.
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Tel: 781/329-4700
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© Analog Devices, Inc., 1998
