13-Bit to 26-Bit Registered Buffer
PC2700-/PC3200-Compliant
CY2SSTV16859
Cypress Semiconductor Corporation
•
3901 North First Street
•
San Jose
, CA 95134
•
408-943-2600
Document #: 38-07463 Rev. *B
Revised July 29, 2003
Features
• Differential clock inputs up to 280 MHz
• Supports LVTTL switching levels on the RESET# pin
• Output drivers have controlled edge rates, so no
external resistors are required.
• Two KV ESD protection
• Latch-up performance exceeds 100 mA per JESD78,
Class II
• 64-pin TSSOP/JEDEC and 56-pin QFN package avail-
ability
• JEDEC specification supported
Description
This 13-bit to 26-bit registered buffer is designed for 2.3V to
2.7 VDD operations.
All inputs are compatible with the JEDEC Standard for SSTL-2,
except the LVCMOS reset (RESET#) input. All outputs are
SSTL_2, Class II compatible.
The CY2SSTV16859 operates from a differential clock (CLK
and CLK#) of frequency up to 280 MHz. Data are registered at
crossing of CLK going high and CLK# going low.
When RESET# is low, the differential input receivers are
disabled, and undriven (floating) data and clock inputs are
allowed. The LVCMOS RESET# input must always be held at
a valid logic high or low level.
To ensure defined outputs from the register before a stable
clock has been supplied, RESET# must be held in the low
state during power up.
In the DDR DIMM application, RESET# is completely
asynchronous with respect to CLK# and CLK. Therefore, no
timing relationship can be guaranteed between the two. When
entering reset, the register is cleared and the outputs are
driven low quickly, relative to the time to disable the differential
input receivers, thus ensuring no glitches on the output.
However, when coming out of reset, the register becomes
active quickly, relative to the time to enable the differential
input receivers.
Block Diagram
Pin Configuration
D1
VREF
CLK #
Q1A
Q1B
To 12 Other Channels
CLK
RESET #
D
C
R
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
Q13A
Q12A
Q11A
Q10A
Q9A
VDDQ
GND
Q8A
Q7A
Q6A
Q5A
Q4A
Q3A
Q2A
GND
Q1A
Q13B
VDDQ
Q12B
Q11B
Q10B
Q9B
Q8B
Q7B
Q6B
GND
VDDQ
Q5B
Q4B
Q3B
Q2B
Q1B
64
63
62
61
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
VDDQ
GND
D13
D12
VDD
VDDQ
GND
D11
D10
D9
GND
D8
D7
RESET #
GND
CLK #
CLK
VDDQ
VDD
VREF
D6
GND
D5
D4
D3
GND
VDDQ
VDD
D2
D1
GND
VDDQ
64 TSSOP Package
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