IDT74SSTU32D869 Datasheet, PDF (1/16 Pages) Integrated Device Technology – 14-BIT 1:2 REGISTERED BUFFER WITH PARITY

IDT74SSTU32D869
14-BIT 1:2 REGISTERED BUFFER WITH PARITY
14-BIT 1:2 REGISTERED
BUFFER WITH PARITY
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IDT74SSTU32D869
FEATURES:
• 1.8V Operation
• Designed to drive low impedance nets
• SSTL_18 style clock and data inputs
• Differential CLK input
• Control inputs compatible with LVCMOS levels
• Center input architecture for optimum PCB design
• Latch-up performance exceeds 100mA
• ESD >2000V per MIL-STD-883, Method 3015; >200V using
machine model (C = 200pF, R = 0)
• Available in 150-pin CTBGA package
APPLICATIONS:
• Along with CSPU877/A/D DDR2 PLL, provides complete solution
for DDR2 DIMMs
• Optimized for DDR2-400/533 [PC2-3200/4300] Raw card L
DESCRIPTION:
The SSTU32D869 is a 14-bit 1:2 configurable registered buffer designed
for 1.7V to 1.9V VDD operation. All clock and data inputs are compatible with
the JEDEC standard for SSTL_18. The control inputs are LVCMOS. All
outputs are 1.8V CMOS drivers that have been optimized to drive the DDR2
DIMM load.
The SSTU32D869 operates from a differential clock (CLK and CLK).
Data are registered at the crossing of CLK going high and CLK going low.
The SSTU32D869 includes a parity checking function. The SSTU32D869
accepts parity bits from the memory controller at its input pins PARIN[1:2],
compares it with the data received on the D-inputs, and indicates whether
a parity error has occured on its open-drain PTYERR[1:2] pins (active low).
When used as a single device, the C1 inputs are tied low. In this
configuration, the partial-parity-out (PPO[1:2]) and PTYERR[1:2] signals
are produced two clock cycles after the corresponding data output. When
used in pairs, the C1 inputs of the first register are tied low and the C1 inputs
of the second register are tied high. The PTYERR[1:2] outputs of the first
SSTU32D869 is left floating and the valid error information is latched on the
PTYERR[1:2] outputs of the second SSTU32D869 .
This device supports low-power standby operation. When the reset input
(RESET) is low, the differential input receivers are disabled, and undriven
(floating) data, clock, and reference voltage (VREF) inputs are allowed. In
addition, when RESET is low all registers are reset, and all outputs are
forced low. The LVCMOS RESET and Cx inputs 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 DDR2 DIMM application, RESET is specified to be completely
asynchronous with respect to CLK and CLK. Therefore, no timing
relationship can be guaranteed between the two. When entering reset, the
register will be cleared and the outputs will be driven low quickly, relative
to the time to disable the differential input receivers. However, when coming
out of a 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
SSTU32D869 must ensure that the outputs will remain low, thus ensuring
no glitches on the outputs.
The device monitors the DCS input and will gate the Qn outputs from
changing states when DCS is high. If the DCS input is low, the Qn outputs
will function normally. The RESET input has priority over the DCS control
and will force the Qn outputs low and the PTYERR[1:2] outputs high. The
EF[0:3] inputs control the driver strength and slew rate for both the A and
B outputs independently.
This device also supports low-power active operation by monitoring both
system chip select (DCS and CSR) inputs and will fate the Qn and PPO
outputs from changing states when both DCS and CSR inputs are high. If
either DCS and CSR input is low, the Qn and PPO outputs will function
normally. Also, if the DCS and CSR are high, the device will gate the
PTYERR[1:2] outputs from changing states. If the DCS and CSR are low,
the PTYERR[1:2] will function normally. The RESET input has priority over
the DCS and CSR control. When driven low, they will force the Qn and
PPO outputs low and the PTYERR[1:2] outputs 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 the DCS would be the same
as for the other D data inputs. To control the low-power mode with DCS
only, then the CSR input should be pulled up to VDD through a pullup resistor.
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
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c 2005 Integrated Device Technology, Inc.
JANUARY 2005
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