W255 Datasheet, PDF (8/9 Pages) SpectraLinear Inc – 200 MHz 24-Output Buffer for 4 DDR or 3 SDRAM DIMMS

Layout Example SDRAM (Mixed Voltage)
+3.3V Supply
FB
VDDQ3
0.005 mF 10 mF
C4
C3
GG
1
G
2^V
3^G
4
5
6
7G
G
8^V
9
10
11 ^G
G
12^V
13 ^G
14 ^G
15
16 G
G
17^V
18 ^G
19
20
21
22
G
23^V
24 ^G
W255
+2.5V Supply
VDDQ2
FB
10 mF
C1
G
0.005 mf
C2
G
G ⁴⁸
V ₄₇
G
46
45
44
43
G 42
V ₄₁
G
G ₄₀
39
G 38
V ₃₇
G
G ₃₆
G ₃₅
34
G ₃₃
V ₃₂
G
G ₃₁
30
G
29
28
27
G ₂₆
25
FB = Dale ILB1206 - 300 (300:@ 100 MHz) or TDK ACB 2012L-120
Ceramic Caps C1 and C3 = 10–22 PFC2 & C4 = 0.005 PF C6 = 0.1PF
G = VIA to GND plane layer V = VIA to respective supply plane layer
Note: Each supply plane or strip should have a ferrite bead and capacitors
All bypass caps = 0.1PF ceramic
Rev 1.0, November 25, 2006
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