®
®
ADS-943
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
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 AN-8, "Heat Sinks for DIP Data
Converters", or contact DATEL directly, for additional
information.
N
START
CONVERT
20ns typ.
333nsec
10ns typ.
INTERNAL S/H
125ns typ.
Hold
Acquisition Time
208ns typ.
215ns max.
N+1
125ns typ.
35ns typ.
EOC
130ns
Conversion Time
120ns min., 130ns typ.,
140ns max.
30ns typ.
10ns max.
OUTPUT
DATA
Data N-1 Valid
Data N Valid
283ns typ.
Invalid
Data
Data N+1 Valid
50ns typ.
Note: 1. Scale is approximately 20ns per division. Sampling rate = 3MHz.
2. The start convert positive pulse width must be between either 10 and 110nsec or
160 and 300nsec (when sampling at 3MHz) to ensure proper operation. For sampling
rates lower than 3MHz, the start pulse can be wider than 300nsec, however a minimum
pulse width low of 30nsec should be maintained. A 3MHz clock with a 20nsec positive
pulse width is used for all production testing.
Figure 4. ADS-943 Timing Diagram
5
MURATA-PS [ MURATA POWER SOLUTIONS INC. ]
