AD12401-326JWS Analog Devices Inc, AD12401-326JWS Datasheet - Page 26

• Manufacturer Part Number: AD12401-326JWS
• Description: IC,A/D CONVERTER,DUAL,12-BIT,MODULE
• Manufacturer: Analog Devices Inc

Specifications of AD12401-326JWS

• Number Of Bits: 12
• Sampling Rate (per Second): 326M
• Data Interface: Parallel
• Number Of Converters: 2
• Power Dissipation (max): 6.8W
• Voltage Supply Source: Analog and Digital
• Operating Temperature: 0°C ~ 60°C
• Package / Case: Module
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

AD12401
LAYOUT GUIDELINES
The AD12401 requires a different approach from traditional
high speed ADC system layouts. While the AD12401’s internal
PCB isolates digital and analog grounds, these planes are tied
together through the product’s aluminum case structure.
Therefore, the decision to isolate the analog and digital grounds
on the system PCB has additional factors to consider.
For example, if the AD12401 is attached with conductive
thermal interface material to the system PCB, there is
essentially no benefit to keeping the analog and digital ground
planes separate. If neither thermal interface material nor
nonconductive interface material is used, system architects
must consider the ground loop that is created if analog and
digital planes are tied together directly under the AD12401.
This EMI-based decision must be considered on a case-by-case
basis and is largely dependent on the other sources of EMI in
the system. One critical consideration is that a 12-bit perform-
ance requirement (–74 dBc) requires keeping conducted EMI
currents (referenced to the input of the AD12401) below 4.5 μA.
All the characterization and testing of the AD12401 is performed
using a system that isolated these ground planes.
If thermal interface material is used in the final system design,
the following layout factors need to be considered: open solder
mask on the area that contacts the interface material and the
thickness of the ground plane. While this should be analyzed in
each specific system design, the use of solder mask can negate
any advantage achieved by using the thermal interface material,
and its use should be carefully considered. The ground plane
thickness does not have a major impact on the thermal per-
formance, but if design margin is slight, additional thickness
can yield incremental improvements.
Rev. A | Page 26 of 28
PCB INTERFACE
Figure 38 provides the mounting hole footprint for assembling
the AD12401 to the second-level assembly. The diagram is
referenced to the center of the mating QTE connector. Refer to
the QTE/QSE series connector documentation at www.samtec.com
for the SMT footprint of the mating connector.
The top view of the second-level assembly footprint provides a
diagram of the second-level assembly locating tab locations for
mating the Samtec QTE-060-01-L-A-K-TR terminal strip on
the AD12401 to a QSE-060-01-L-A-K-TR socket on the second-
level assembly. The diagram is referenced to the center of the
QTE terminal strip on the AD12401 and the mounting holds
for the screws, which holds the AD12401 to the second-level
assembly board. The relationship of these locating tabs is based
on information provided by Samtec (connector supplier) and
should be verified with Samtec by the customer.
Mating and unmating forces—the knifing or peeling action of
applying force to one end or one side—must be avoided to
prevent damage to the connector and guidepost.