Rev. 0.7 / Jun. 2009

3

1

240pin Registered DDR2 SDRAM DIMMs

Input/Output Functional Description

Symbol

Type

Polarity

Pin Description

CK0

IN

Positive

Edge

Positive line of the differential pair of system clock inputs that drives input to the on-DIMM PLL.

CK0IN

Negative

Edge

Negative line of the differential pair of system clock inputs that drives input to the on-DIMM PLL.

CKE[1:0]

IN

Active High

Activates the DDR2 SDRAM CK signal when high and deactivates the CK signal when low. By deactivat-

ing the clocks, CKE low initiates the Power Down mode or the Self Refresh mode.

S[1:0]

IN

Active Low

Enables the associated DDR2 SDRAM command decoder when low and disables the command

decoder when high. When the command decoder is disabled, new commands are ignored but previous

operations continue. Rank 0 is selected by S0; Rank 1 is selected by S1

ODT[1:0]

IN

Active High

On-Die Termination signals.

RAS, CAS, WE

IN

Active Low

When sampled at the positive rising edge of the clock. RAS,CAS and WE(ALONG WITH S) define the

command being entered.

Vref

Supply

Reference voltage for SSTL18 inputs

Supply

Power supplies for the DDR2 SDRAM output buffers to provide improved noise immunity. For all current

BA[2:0]

IN

-

Selects which DDR2 SDRAM internal bank of Eight is activated.

A[9:0],A10/AP

A[13:11]

IN

-

During a Bank Activate command cycle, Address input difines the row address(RA0~RA13)

During a Read or Write command cycle, Address input defines the column address when sampled at the

cross point of the rising edge of CK and falling edge of CK. In addition to the column address, AP is used

to invoke autoprecharge operation at the end of the burst read or write cycle. If AP is high., autopre-

charge is selected and BA0-BAn defines the bank to be precharged. If AP is low, autoprecharge is dis-

abled. During a Precharge command cycle., AP is used in conjunction with BA0-BAn to control which

bank(s) to precharge. If AP is high, all banks will be precharged regardless of the state of BA0-BAn

inputs. If AP is low, then BA0-BAn are used to define which bank to precharge.

DQ[63:0],

CB[7:0]

IN

-

Data and Check Bit Input/Output pins.

DM[8:0]

IN

Active High

DM is an input mask signal for write data. Input data is masked when DM is sampled High coincident with

that input data during a write access. DM is sampled on both edges of DQS. Although DM pins are input

only, the DM loading matches the DQ and DQS loading.

Supply

DQS[17:0]

I/O

Positive

Edge

Positive line of the differential data strobe for input and output data

DQS[17:0]

I/O

Negative

Edge

Negative line of the differential data strobe for input and output data

SA[2:0]

IN

-

EEPROM address range.

SDA

I/O

-

This is a bidirectional pin used to transfer data into or out of the SPD EEPROM. A resister may be con-

SCL

IN

-

This signal is used to clock data into and out of the SPD EEPROM. A resistor may be connected from

VDDSPD

Supply

Power supply for SPD EEPROM. This supply is separate from the VDD/VDDQ power plane. EEPROM

supply is operable from 1.7V to 3.6V.

RESET

IN

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 register(s) will be set to low

level (the PLL will remain synchronized with the input clock)

Par_In

IN

Parity bit for the Address and Control bus(“1”. Odd, “0”.Even)

Err_Out

OUT

Parity error found in the Address and Control bus

TEST

Used by memory bus analysis tools (unused on memory DIMMs)