HI5628EVAL1 Intersil, HI5628EVAL1 Datasheet - Page 5

• Manufacturer Part Number: HI5628EVAL1
• Description: EVALUATION BOARD FOR LQFPHI5628
• Manufacturer: Intersil

Specifications of HI5628EVAL1

• Number Of Dac's: 2
• Number Of Bits: 8
• Outputs And Type: 2, Differential
• Sampling Rate (per Second): 125M
• Data Interface: Parallel
• Settling Time: 15ns
• Dac Type: Current
• Voltage Supply Source: Analog and Digital
• Operating Temperature: -40°C ~ 85°C
• Utilized Ic / Part: HI5628
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Appendix A Description of Architecture
The segmented current source architecture has the ability to
improve the converter’s performance by reducing the amount
of current that is switching at any one time. In traditional
architectures, major transition points required the converter
to switch on or off large amounts of current. In a traditional 8-
bit R/2R ladder design, for example, the midscale transition
required equal amounts of currents switching on and off. In a
segmented current source arrangement, transitions such as
midscale become one in which you simply have an additional
intermediate current source turning on and several minor
ones turning off. In the case of the HI5628, there are 31
intermediate current segments that represent the 5 MSBs
and 3, binary-weighted current sources representing each of
the 3 LSBs. See the Functional Block Diagram in the data
sheet for a visual representation. To relate the midscale
transition example to the HI5628, consider the following:
IBM COMPATIBLE PERSONAL COMPUTER
WITH HSP-EVAL
SOFTWARE
INCLUDED
CIRCUIT
CLOCK
FIGURE 2. INTERSIL HI5628/DDS EVALUATION SYSTEM SETUP BLOCK DIAGRAM
5
NCOM EVALUATION BOARD
OR A DATA GENERATOR
HSP-EVAL/HSP45116
HSP-EVAL/HSP45116DB
PC INTERFACE
NUMERICALLY
CONTROLLED
OSCILLATOR
EVAL KIT
Application Note 9840
8 BITS
8 BITS
SUPPLY
POWER
+5V
Code 01111111 would be represented by 15 intermediate
current segments and each of the 3 LSB current sources all
turned on. To transition to code 10000000 would simply
require turning off the 3 LSB current sources and turning on
the next intermediate current segment, bringing the total
amount of current switching at this ‘major’ code transition
equal to the same amount switching at 30 other code
transition points in the code ramp from 0 to 255, so that the
total glitch energy is distributed more evenly.
DAC MODULE
HI5628EVAL1
I CHANNEL
Q CHANNEL
SUPPLY
POWER
HI5628
+5V
SPECTRUM ANALYZER
CABLE
SMA
50Ω