®
®
ADS-947
THERMAL REQUIREMENTS
All DATEL sampling A/D converters are fully characterized
and specified over operating temperature (case) ranges of
0 to +70°C and –40 to +100°C. All room temperature
(T
A
= +25°C) production testing is performed without the use
of heat sinks or forced air cooling. Thermal impedance
figures for each device are listed in their respective
specification tables.
These devices do not normally require heat sinks, however,
standard precautionary design and layout procedures should
be used to ensure devices do not overheat. The ground and
power planes beneath the package, as well as all pcb signal
runs to and from the device, should be as heavy as possible
to help conduct heat away from the package.
Electrically-insulating, thermally-conductive "pads" may be
installed underneath the package. Devices should be soldered
to boards rather than socketed, and of course, minimal air flow
over the surface can greatly help reduce the package
temperature.
In more severe ambient conditions, the package/junction
temperature of a given device can be reduced dramatically
(typically 35%) by using one of DATEL's HS Series heat sinks.
See Ordering Information for the assigned part number. See
page 1-183 of the DATEL Data Acquisition Components Catalog
for more information on the HS Series. Request DATEL
Application Note AN8, "Heat Sinks for DIP Data Converters",
or contact DATEL directly, for additional information.
N
START
CONVERT
20ns
typ.
N+1
10ns typ.
INTERNAL S/H
Acquisition Time
35ns
typ.
Hold
65ns typ.
(61ns min., 68ns max.)
25ns typ. (22ns min., 28ns max.)
INTERNAL EOC
15ns
DATA N-1 VALID
DATA
VALID
40ns typ.
(±5ns)
DATA N VALID
40ns typ.
(±5ns)
Conversion Time
70ns typ.
40ns max.
OUTPUT
DATA
DATA N-1 VALID
50ns typ.
(±5ns)
50ns typ.
DATA N VALID
INVALID DATA
Notes:
1. Scale is approximately 5ns per division. Sampling rate = 10MHz.
2. The start convert pulse must be between 20 and 50ns wide or between 80 and 100ns wide (when sampling at 10MHz)
to ensure proper operation. For sampling rates less than 10MHz, the start pulse can be wider than 85nsec, however a minimum
pulse width low of 15nsec should be maintained. A 10MHz clock with a 20nsec positive pulse width is used for all production testing.
Figure 4. ADS-947 Timing Diagram
5
MURATA-PS [ MURATA POWER SOLUTIONS INC. ]
