HI5728EVAL1 Intersil, HI5728EVAL1 Datasheet - Page 3

• Manufacturer Part Number: HI5728EVAL1
• Description: EVALUATION PLATFORM TQFPHI5728
• Manufacturer: Intersil

Specifications of HI5728EVAL1

• Number Of Dac's: 2
• Number Of Bits: 10
• Outputs And Type: 2, Differential
• Sampling Rate (per Second): 125M
• Data Interface: Parallel
• Settling Time: 35ns
• Dac Type: Current
• Voltage Supply Source: Analog and Digital
• Operating Temperature: -40°C ~ 85°C
• Utilized Ic / Part: HI5728
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Differential Output
The board is also configured with the following transformer
output which will result in an output voltage amplitude that is
twice that of I
resistive loading seen by the current outputs (~12.5 =
(50//50//25). The transformer used in this circuit is a Mini-
Circuits 1:1 RF Transformer, T1-1T. The impedance looking
back into the transformer from the 50 spectrum analyzer is
50 (100 /2), so proper termination is achieved and
reflections are minimized. The transformer benefits the user
by reducing the even-order harmonics and therefore
increasing the SFDR (Spurious Free Dynamic Range). It can
be taken out of the output by removing the zero ohm
jumpers, R51, 57, 70, and 72. With the transformers
removed, SMAs 1-4 should be used to measure the output
voltages across the included 50 loads.
Sleep
The converter can be put into ‘sleep’ mode by connecting pin
8 to either of the converter’s supply voltages. For normal
operation, it is recommended that pin 8 be tied to ground.
However, the sleep pin does have an active pulldown
current, so the pin can be left disconnected. On the
evaluation board, jumper J1 is provided for controlling the
sleep pin. Remove the jumper from J1 for normal operation
and replace it for sleep mode.
Power Supply(ies) and Ground(s)
The user can operate from either a single supply or dual
supplies. The DAC is designed to function with the digital
and analog voltages at the same value or at different values.
The DAC can be driven with a 3 or 3.3V digital supply and a
5V analog supply. In compliance with the absolute maximum
ratings for the DAC listed in the datasheet, the digital input
voltages should not be more than DV
power supply wire can be attached to either DV
AV
together on the board using regular wire if a single supply is
desired. The board uses dual ground planes connected at a
single point near the converter (this is the recommended
configuration). For dual supply mode, connect a power
supply wire to both AV
DGND1 and AGND1 independently.
PIN 17 (20)
PIN 16 (21)
HI5728
DD1
, and then the DV
OUT
IOUTA (QOUTA)
IOUTB (QOUTB)
x Req, where Req is the equivalent
DD1
DD1
100
FIGURE 1.
50
50
and DV
3-3
and AV
DD1
DD1
DD
V
and ground wires to
OUT
+ 0.3V. A single
holes jumpered
50
= (2 x I
DD1
Application Note 9827
OUT
or
x R
EQ
)V
Clock Inputs
The elaborate nature of the clock input circuit (see the
schematic) achieves versatility. It provides the means to drive
both channels from a single clock via the VME connector, or to
drive each with separate clocks via SMAs 8 and 9. Notice that
the 0 resistors (R28, 29, 50 and 53) are used as jumpers to
enable the different clock sources without degrading signal
integrity, or they can be replaced by nominal value resistors if
series input termination(s) are desired on the clock(s).
Input Termination
For clock rates below 50MSPS, the method of input
termination on the data and clock lines could be open, 50 ,
or nominal series, depending on the current drive available
from the digital source. The performance of the converter
should not vary greatly with the termination method for these
update rates. For clock rates above 50MSPS, it may be
necessary that 50 termination resistors be used on this
board to achieve optimum spectral purity. If the digital
pattern source cannot drive this load, it is recommended that
200 series resistors be used at high clock rates. The board
is shipped with 200 series resistors on the data and clock
lines. Notice that the PCB footprints are available on the
board for either termination technique. For high clock rates,
adjustment of the timing between the clock and the data may
be necessary for optimum performance. When implementing
the HI5728 onto a board that contains the digital data/clock
source in close proximity to the DAC, it is unlikely that any
termination resistors will be required.
Note that the board is also shipped with both input channels
tied together via 0
the board. This is done so that both channels can be
evaluated from a single pattern generator. If 50 termination
is used while the channels are tied together, it should be
obvious that they are only needed on one channel, not both;
else you will be driving 25 .
Getting Started
A summary of the external supplies, equipment, and signal
sources needed to operate the board is given below:
Attach a +3V to +5V power supply to the evaluation board
connections labeled DV
bits from the data generator to the evaluation board, preferably
by using a male, 64 or 96-pin VME (Versa Module Eurocard)
connector that mates with the eval board. See the schematic for
the correct pin connections. The middle row of the VME is not
used, which is why either a 64 or 96-pin connector will work.
1. +3V to +5V power supply(ies) for HI5728.
2. Data Generator capable of generating 10-bit patterns.
3. Clock source (usually part of the Data Generator).
4. Spectrum Analyzer or Oscilloscope for viewing the output
The HSP-EVAL with the HSP45116 NCOM daughter
board is an option (see ‘Learning Your Way Around’).
of the converter.
402 package resistors on the bottom of
DD1
and AV
DD1
. Connect the 10 input