Document
Quad, 16-Bit DAC with 5 ppm/°C On-Chip Reference in 14-Lead TSSOP
AD5666
05298-001
FEATURES
Low power quad 16-bit DAC 14-lead TSSOP On-chip 1.25 V/2.5 V, 5 ppm/°C reference Power down to 400 nA @ 5 V, 200 nA @ 3 V 2.7 V to 5.5 V power supply Guaranteed monotonic by design Power-on reset to zero scale or midscale 3 power-down functions Hardware LDAC with LDAC override function CLR function to programmable code SDO daisy-chaining option Rail-to-rail operation
APPLICATIONS
Process control Data acquisition systems Portable battery-powered instruments Digital gain and offset adjustment Programmable voltage and current sources Programmable attenuators
FUNCTIONAL BLOCK DIAGRAM
AD5666
LDAC
SCLK SYNC
INTERFACE LOGIC
DIN
SDO
VDD
VREFIN/VREFOUT
INPUT REGISTER
DAC REGISTER
INPUT REGISTER
DAC REGISTER
INPUT REGISTER
DAC REGISTER
INPUT REGISTER
POWER-ON RESET
DAC REGISTER
1.25V/2.5V REF
STRING DAC A
BUFFER
STRING DAC B
BUFFER
STRING DAC C
BUFFER
STRING DAC D
BUFFER
POWER-DOWN LOGIC
LDAC CLR
POR
Figure 1.
GND
VOUTA VOUTB VOUTC VOUTD
GENERAL DESCRIPTION
The AD5666 is a low power, quad, 16-bit, buffered voltageoutput DAC. The part operates from a single 2.7 V to 5.5 V supply and is guaranteed monotonic by design.
The AD5666 has an on-chip reference with an internal gain of 2. The AD5666-1 has a 1.25 V 5 ppm/°C reference, giving a full-scale output of 2.5 V; the AD5666-2 has a 2.5 V 5 ppm/°C reference, giving a full-scale output of 5 V. The on-board reference is off at power-up, allowing the use of an external reference. The internal reference is turned on by writing to the DAC.
The part incorporates a power-on reset circuit that ensures that the DAC output powers up to 0 V (POR pin low) or to midscale (POR pin high) and remains powered up at this level until a valid write takes place. The part contains a power-down feature that reduces the current consumption of the device to 400 nA at 5 V and provides software-selectable output loads while in power-down mode for any or all DAC channels.
The outputs of all DACs can be updated simultaneously using the LDAC function, with the added functionality of user-selectable DAC channels to simultaneously update. There is also an asynchronous CLR that clears all DACs to a software-selectable code—0 V, midscale, or full scale.
The AD5666 utilizes a versatile 3-wire serial interface that operates at clock rates of up to 50 MHz and is compatible with standard SPI®, QSPI™, MICROWIRE™, and DSP interface standards. The on-chip precision output amplifier enables rail-to-rail output swing.
PRODUCT HIGHLIGHTS
1. Quad, 16-bit DAC. 2. On-chip 1.25 V/2.5 V, 5 ppm/°C reference. 3. Available in 14-lead TSSOP. 4. Selectable power-on reset to 0 V or midscale. 5. Power-down capability. When powered down, the DAC
typically consumes 200 nA at 3 V and 400 nA at 5 V.
Rev. D
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 that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarksandregisteredtrademarksarethepropertyoftheirrespectiveowners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113 ©2005–2010 Analog Devices, Inc. All rights reserved.
AD5666
TABLE OF CONTENTS
Features .............................................................................................. 1 Applications....................................................................................... 1 Functional Block Diagram .............................................................. 1 General Description ......................................................................... 1 Product Highlights ........................................................................... 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3
AC Characteristics........................................................................ 7 Timing Characteristics ................................................................ 8 Absolute Maximum Ratings.......................................................... 10 ESD Caution................................................................................ 10 Pin Configuration and Function Descriptions........................... 11 Typical Performance Characteristics ........................................... 12 Terminology .................................................................................... 18 Theory of Operation ...................................................................... 20 D/A Section....