Datasheet

REV. 0
AD8369
–17–
31012498761152 131
15 22 2416 21201918 231714 25
D-SUB 25 PIN MALE
1nF
R
L
1nF
1nF
1nF
910111213141516
PWUP VPOS SENB FILT CMDC OPHI
INHI
COMM
INLO DENBCOMM BIT0 BIT1 BIT2 BIT3
AD8369
OPLO
C7
0.1␮F
87654321
C5
0.1␮F
INⴙ
J1
INⴚ
J2
TC4-1W
R1
0⍀
T1
R2
0⍀
C4
C3
OUTⴙ
J6
OUTⴚ
J7
TC4-1W
R12
0⍀
R11
0⍀
T2
C8
1nF
R5
OPEN
V
S
PWUP
SW 2
PWDN
2
13
C8
1nF
R6
0⍀
R7
0⍀
R8
0⍀
R9
0⍀
R10
0⍀
V
S
V
S
A
B
1
14
SW3
SW4
R3
1k⍀
R13
1k⍀
LATCH
CLOCK
DATA
R4
1k⍀
C9
OPEN
3467 10912
25 8 11
28
4
SW1
1
2
3
C1
C2
Figure 9. Evaluation Board Schematic
Key considerations when laying out an RF trace with a controlled
impedance include:
• Space the ground plane to either side of the signal trace at least
3 line-widths away to ensure that a microstrip (vertical dielec-
tric) line is formed, rather than a coplanar (lateral dielectric)
waveguide.
• Ensure that the width of the microstrip line is constant and
that there are as few discontinuations (component pads, etc.)
as possible along the length of the line. Width variations
cause impedance discontinuities in the line and may result
in unwanted reflections.
• Do not use silkscreen over the signal line; this will alter the
line impedance.
• Keep the length of the input and output connection lines as
short as possible.
3W 3WW
H
T
⑀
r
Figure 8. Cross-Sectional View of a PC Board
The AD8369 contains both digital and analog sections. Care
should be taken to ensure that the digital and analog sections
are adequately isolated on the PC board. The use of separate
ground planes for each section connected at only one point via a
ferrite bead inductor will ensure that the digital pulses do not
adversely affect the analog section of the AD8369.