SSTUM32866 Datasheet, PDF (9/28 Pages) NXP Semiconductors – 1.8 V 25-bit 1 : 1 or 14-bit 1 : 2 configurable registered buffer with parity for DDR2-1G RDIMM applications

NXP Semiconductors
SSTUM32866
1.8 V DDR2-1G configurable registered buffer with parity
The device also supports low-power active operation by monitoring both system chip
select (DCS and CSR) inputs and will gate the Qn and PPO outputs from changing states
when both DCS and CSR inputs are HIGH. If either DCS or CSR input is LOW, the Qn
and PPO outputs will function normally. The RESET input has priority over the DCS and
CSR control and when driven LOW will force the Qn and PPO outputs LOW, and the
QERR output HIGH. If the DCS control functionality is not desired, then the CSR input can
be hard-wired to ground, in which case, the setup time requirement for DCS would be the
same as for the other Dn data inputs. To control the low-power mode with DCS only, then
the CSR input should be pulled up to V_DD through a pull-up resistor.
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 DDR2 RDIMM application, RESET is specified to be completely asynchronous with
respect to CK and CK. Therefore, no timing relationship can be guaranteed between the
two. When entering reset, the register will be cleared and the Qn outputs will be driven
LOW quickly, relative to the time to disable the differential input receivers. However, when
coming out of reset, the register will become active quickly, relative to the time to enable
the differential input receivers. As long as the data inputs are LOW, and the clock is stable
during the time from the LOW-to-HIGH transition of RESET until the input receivers are
fully enabled, the design of the SSTUM32866 must ensure that the outputs will remain
LOW, thus ensuring no glitches on the output.
7.1 Function table
Table 4. Function table (each flip-flop)
L = LOW voltage level; H = HIGH voltage level; X = don’t care; ↑ = LOW-to-HIGH transition; ↓ = HIGH-to-LOW transition.
Inputs
Outputs^[1]
RESET
DCS
CSR
CK
CK
Dn, DODTn, Qn
DCKEn
QCS
QODT,
QCKE
H
L
L
↑
↓
L
L
L
L
H
L
L
↑
↓
H
H
L
H
H
L
H
L
L
L or H
L or H
X
Q₀
Q₀
Q₀
H
↑
↓
L
L
L
L
H
L
H
↑
↓
H
H
L
H
H
L
H
H
H
L or H
L or H
X
Q₀
Q₀
Q₀
L
↑
↓
L
L
H
L
H
H
L
↑
↓
H
H
H
H
H
H
L
L or H
L or H
X
Q₀
Q₀
Q₀
H
H
H
↑
↓
L
Q₀
H
L
H
H
H
↑
↓
H
Q₀
H
H
H
H
H
L or H
L or H
X
Q₀
Q₀
Q₀
L
X or floating X or floating X or floating X or floating X or floating
L
L
L
[1] Q₀ is the previous state of the associated output.
SSTUM32866_1
Product data sheet
Rev. 01 — 29 June 2007
© NXP B.V. 2007. All rights reserved.
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