HYS72T[256/128/64][0/2][0/2]0[G/H]R-[5/3.7]-A
Registered DDR2 SDRAM Modules
Data Sheet
Preliminary
7
Rev. 0.85, 2004-04
1.7 Registered DIMM Input/Output Functional Description
Symbol
Type
Polarity
Function
CK0, CK0
Input
Cross point
The system clock inputs. All address and command lines are sampled on the cross point of
the rising edge of CK and the falling edge of CK. An on-board DLL circuit is driven from the
clock inputs and output timing for read operations is synchronized to the input clock.
CKE[1:0]
Input
Active High
CKE high activates and CKE low deactivates internal clock signals and device input buffers
and output drivers of the SDRAMs. Taking CKE low provides Precharge Power-Down and
Self-Refresh operation (all banks idle), or Active Power-Down (row Active in any bank).
CS[1:0]
Input
Active Low
Enables the associated SDRAM command decoder when low and disables decoder when
high. When decoder is disabled, new commands are ignored and previous operations con-
tinue. The input signals also disable all outputs (except CKE and ODT) of the register(s) on
the DIMM when both inputs are high. When both CS[1:0] are high, all register outputs (except
CK, ODT and Chip select) remain in the previous state.
ODT[1:0]
RAS, CAS,
WE
Input
Active High On-Die Termination control signals
Input
Active Low
When sampled at the positive edge of the clock, RAS, CAS and WE define the operation to
be executed by the SDRAM.
DM[8:0]
Input
Active High Masks write data when high, issued concurrently with input data.
BA[1:0]
Input
-
Selects which internal SDRAM memory bank is activated
A[13:0]
Input
-
During Bank Activate command cycle, Address defines the row address. During a Read or
Write command cycle, Address defines the column address. In addition to the column
address, A10(=AP) is used to invoke Auto-Precharge operation at the end of the burst read
or write cycle. If AP is high, Auto Precharge is selected and BA[1:0] defines the bank to be
precharged. If AP is low, Auto-Precharge is disabled. During a Precharge command cycle,
AP is used in conjunction with BA[1:0] to control which bank(s) to precharge. If AP is high, all
banks will be precharged regardless of the state of BA[1:0]. If AP is low, BA[1:0] are used to
define which bank to precharge.
DQ[63:0],
CB[7:0]
I/O
-
Data and Check Bit Input /Output pins.
DQS[17:0],
DQS[17:0]
I/O
Cross point
The data strobes, associated with one data byte, source with data transfer. In Write mode,
the data strobe is sourced by the controller and is centered in the data window. In Read
mode the data strobe is sources by the DDR2 SDRAM and is sent at the leading edge of the
data window. DQS signals are complements, and timing is relative to the crosspoint of
respective DQS and DQS. If the module is to be operated in single ended strobe mode, all
DQS signals must be tied on the system board to VSS and DDR2 SDRAM mode registers
programmed appropriately.
SA[2:0]
Input
-
These signals are tied at the system planar to either VSS or VDDSPD to configure the serial
SPD EEPROM address range
SDA
I/O
-
This bidirectional pin is used to transfer data into and out of the SPD EEPROM. A resistor
maybe connected from the SDA bus line to VDDSPD on the system planar to act as a pull-
up.
SCL
Input
-
This signal is used to clock data into the SPD EEPROM. A resistor maybe connected from
the SCL bus line to VDDSPD on the system planar to act as a pull-up.
RESET
Input
-
The RESET pin is connected to the RST pin on the register and to the OE pin on the PLL.
When low, all register outputs will be driven low and the PLL clocks to the DRAMs and the
register(s) will be set to low level. The PLL will remain synchronized with the input clock.
V
DD,
V
SS
Supply
-
Power and ground for the DDR SDRAM input buffers and core logic.
V
REF
Supply
-
Reference voltage for the SSTL-18 inputs.
V
DDSPD
Supply
-
Serial EEPROM positive power supply, wired to a separated power pin at the connector
which supports from 1.7 Volt to 3.6 Volt.
Note: CS1, ODT1 and CKE1 are used on dual rank modules only
.