®
®
ADS-917
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
200ns
typ.
10ns typ.
Hold
430ns typ.
Acquisition Time
570ns ±40ns
N+1
INTERNAL S/H
70ns ±10ns
90ns typ.
EOC
Conversion Time
420ns ±20ns
35ns max.
74ns max.
OUTPUT
DATA
Data (N – 1) Valid
926ns min.
Notes: 1. f
s
= 500kHz.
2. The ADS-917 is an edge-triggered device. All internal operations
are triggered by the rising edge of the start convert pulse, which
may be as narrow as 20nsec. All production testing is performed
at a 1MHz sampling rate with 200nsec wide start pulses. For
lower sampling rates, wider start pulses may be used, however, a
minimum pulse width low of 20nsec must be maintained.
Figure 4. ADS-917 Timing Diagram
Invalid
Data
Data N Valid
926ns min.
Invalid
Data
5
MURATA-PS [ MURATA POWER SOLUTIONS INC. ]
