ADS-946 ETC, ADS-946 Datasheet - Page 5

• Manufacturer Part Number: ADS-946
• Description: ADS-946 14-Bit/ 8MHz Sampling A/D Converters
• Manufacturer: ETC

THERMAL REQUIREMENTS
All DATEL sampling A/D converters are fully characterized
and specified over operating temperature (case) ranges of
0 to +70°C and –55 to +125°C. All room-temperature
(T
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.
A
®
= +25°C) production testing is performed without the use
Notes:
1. Scale is approximately 5ns per division. Sampling rate = 8MHz.
2. The start convert positive pulse width must be between 10 and 50ns or between 80 and 110ns (when sampling at 8MHz)
INTERNAL S/H
to ensure proper operation. For sampling rates less than 8MHz, the start pulse can be wider than 110nsec, however a
minimum pulse width low of 15nsec should be maintained. An 8MHz clock with a 20nsec positive pulse width is used
for all production testing.
CONVERT
OUTPUT
START
DATA
EOC
®
20ns
typ.
N
Data N-1 Valid
10ns typ.
95ns typ.
78ns min., 85ns typ., 90ns max.
70ns typ.
Figure 4. ADS-946 Timing Diagram
20ns typ.
Hold
Conversion Time
5
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 AN-8, "Heat Sinks for DIP Data Converters," or
contact DATEL directly, for additional information.
Invalid Data
Acquisition Time
30ns typ.
60ns max.
55ns typ.
25ns typ.
10ns typ.
N+1
Data N Valid
ADS-946