Octal, 12-/14-/16-Bit, SPI Voltage Output
denseDAC with 5 ppm/°C, On-Chip Reference
Data Sheet
AD5628/AD5648/AD5668
FEATURES
FUNCTIONAL BLOCK DIAGRAM
VREFIN/VREFOUT
VDD
AD5628/AD5648/AD5668
LDAC
INPUT
REGISTER
INPUT
REGISTER
INPUT
REGISTER
SCLK
INTERFACE
LOGIC
SYNC
INPUT
REGISTER
INPUT
REGISTER
DIN
1.25V/2.5V
REF
DAC
REGISTER
DAC
REGISTER
DAC
REGISTER
DAC
REGISTER
DAC
REGISTER
STRING
DAC A
STRING
DAC B
STRING
DAC C
STRING
DAC D
STRING
DAC E
INPUT
REGISTER
DAC
REGISTER
STRING
DAC F
INPUT
REGISTER
DAC
REGISTER
STRING
DAC G
INPUT
REGISTER
DAC
REGISTER
STRING
DAC H
VOUTB
BUFFER
VOUTC
BUFFER
VOUTD
BUFFER
VOUTE
BUFFER
VOUTF
BUFFER
VOUTG
BUFFER
VOUTH
GND
LDAC1 CLR1
1RU-16
VOUTA
BUFFER
POWER-DOWN
LOGIC
POWER-ON
RESET
APPLICATIONS
BUFFER
AND WLCSP PACKAGE ONLY.
05302-001
Low power, small footprint, pin-compatible octal DACs
AD5668: 16 bits
AD5648: 14 bits
AD5628: 12 bits
14-lead/16-lead TSSOP, 16-lead LFCSP, and 16-ball WLCSP
On-chip 1.25 V/2.5 V, 5 ppm/°C reference
Power down to 400 nA at 5 V, 200 nA at 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 and LDAC override function
CLR function to programmable code
Rail-to-rail operation
Figure 1.
Process control
Data acquisition systems
Portable battery-powered instruments
Digital gain and offset adjustment
Programmable voltage and current sources
Programmable attenuators
GENERAL DESCRIPTION
The AD5628/AD5648/AD5668 devices are low power, octal,
12-/14-/16-bit, buffered voltage-output DACs. All devices
operate from a single 2.7 V to 5.5 V supply and are guaranteed
monotonic by design. The AD5668 and AD5628 are available in
both a 4 mm × 4 mm LFCSP and a 16-lead TSSOP, while the
AD5648 is available in both a 14-lead and 16-lead TSSOP.
The AD5628/AD5648/AD5668 have an on-chip reference with
an internal gain of 2. The AD5628-1/AD5648-1/AD5668-1 have
a 1.25 V 5 ppm/°C reference, giving a full-scale output range
of 2.5 V; the AD5628-2/AD5648-2/AD5668-2 and AD5668-3 have
a 2.5 V 5 ppm/°C reference, giving a full-scale output range of
5 V. The on-board reference is off at power-up, allowing the use
of an external reference. The internal reference is enabled via a
software write.
The part incorporates a power-on reset circuit that ensures that the
DAC output powers up to 0 V (AD5628-1/AD5648-1/AD5668-1,
AD5628-2/AD5648-2/AD5668-2) or midscale (AD5668-3) 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 softwareRev. J
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 updates all DACs to a userprogrammable code—zero scale, midscale, or full scale.
The AD5628/AD5648/AD5668 utilize 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.
2.
3.
4.
5.
Octal, 12-/14-/16-bit DAC.
On-chip 1.25 V/2.5 V, 5 ppm/°C reference.
Available in 14-lead/16-lead TSSOP, 16-lead LFCSP, and
16-ball WLCSP.
Power-on reset to 0 V or midscale.
Power-down capability. When powered down, the DAC
typically consumes 200 nA at 3 V and 400 nA at 5 V.
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