a
Clock Driver
AD246
GENERAL DESCRIPTION
AD246 SPECIFICATIONS
The AD246 is a compact, inexpensive clock driver that can be
used to obtain the required clock from a single 15 V supply. The
circuit shown in Figure 1 (essentially an AD246) can operate at
least 32 AD204s at the rated minimum supply voltage of 14.25 V
and one additional isolator can be operated for each 40 mV
increase in supply voltage up to 15 V.
(Typical @ 25∞C and VS = 15 V, unless otherwise noted.)
Model
AD246JY
AD246JN
OUTPUT*
Frequency
Voltage
25 kHz Nominal 25 kHz Nominal
15 V p-p Nominal 15 V p-p Nominal
Fan Out
32 max
32 max
A supply bypass capacitor is included in the AD246, but if many
AD204s are operated from a single AD246, an external bypass
connector should be used with a value of at least 1 mF for every
five isolators used. Place the capacitor as close as possible to the
clock driver.
POWER SUPPLY
REQUIREMENTS
Input Voltage
Supply Current
Unloaded
15 V ± 5%
15 V ± 5%
35 mA
2.2 mA
35 mA
2.2 mA
15V
6
14
Each AD204
Adds 1 mA
Load on AD204
+VISO or
–VISO Adds
6
5
180pF
TELEDYNE
1
IN914
7
TSC426
C
2
4
10
2
3
CLKOUT
1F
RC
R
Q
CD
4947B
+
5
0.7 mA
0.7 mA
35V
49.9k⍀
IN914
*The high current drive will not support a short to ground.
Specifications are subject to change without notice.
12
9
8
7
4
3
CLK AND
PWR COM
AD246 Pin Designations
Figure 1. Clock Driver
Pin (Y)
Pin (N)
Function
1
2
12
12
1
14
15 V Power In
Clock Output
Common
13
24
Common
OUTLINE DIMENSIONS
AD246JY Package
Dimensions shown in inches and (millimeters)
AD246JN Package
Dimensions shown in inches and (millimeters)
8.40 (0.330) MAX
36.70 (1.445) MAX
25.30 (0.995) MAX
8.90 (0.350)
AD246JN
MAX
FRONT VIEW
15.90
SIDE
VIEW
AD246JY
2.50 (0.100)
MIN
(0.625)
MAX
FRONT VIEW
0.51 (0.020)
0.38 (0.015)
0.51 (0.020)
0.25 (0.010)
0.38 (0.015)
0.25 (0.010)
3.70 (0.145)
1
2.50
(0.100)
MIN
27.90 (1.100)
1.30 (0.050)
NOM
14.00 (0.550)
2.90 (0.115)
2.50 (0.100)
NOM
12
0.38 (0.015)
0.25 (0.010)
5.00 (0.197)
1
12.70
(0. 500)
17.80
BOTTOM VIEW
(0.700)
2.90
13
(0.115)
24
14
2.50
BOTTOM
VIEW
C
L
(0.100)
25.40 (1.000)
2
12
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN
REV. 0
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reliable. However, no responsibility is assumed by Analog Devices for its
use, norforanyinfringementsofpatentsorotherrightsofthirdpartiesthat
may result from its use. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices.
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© Analog Devices, Inc., 2002