Symbol
Type
Function
Address Inputs: Provide the row address for ACTIVATE Commands and the column
address for Read/Write commands to select one location out of the memory array in the
A0 - A16
Input respective bank. A10/AP, A12/BC_n, RAS_n/A16, CAS_n/A15, and WE_n/A14 have
additional functions. See other rows. The address inputs also provide the op-code during
Mode Register Set commands.
Auto-precharge: A10 is sampled during Read/Write commands to determine whether
Autoprecharge should be performed to the accessed bank after the Read/Write
operation. (HIGH: Autoprecharge; LOW: no Autoprecharge). A10 is sampled during a
Precharge command to determine whether the Precharge applies to one bank (A10
A10 / AP
Input
LOW) or all banks (A10 HIGH). If only one bank is to be precharged, the bank is selected
by bank addresses.
Burst Chop: A12/BC_n is sampled during Read and Write commands to determine if
Input burst chop (on-the-fly) will be performed. (HIGH, no burst chop; LOW: burst chopped).
See command truth table for details.
A12 / BC_n
RESET_n
CMOS Active Low Asynchronous Reset: Reset is active when RESET_n is LOW, and inactive
Input when RESET_n is HIGH. RESET_n must be HIGH during normal operation.
Data Input/ Output: Bi-directional data bus. If CRC is enabled via Mode register then
Input/ CRC code is added at the end of Data Burst. Any DQ from DQ0-DQ3 may indicate the
Output internal Vref level during test via Mode Register Setting MR4 A4=High. Refer to vendor
specific data sheets to determine which DQ is used.
DQ
Data Strobe: output with read data, input with write data. Edge-aligned with read data,
centered in write data. DDR4 SDRAMs support differential data strobe only and does not
support single-ended.
Input/
Output
DQS_t, DQS_c,
Command and Address Parity Input : DDR4 Supports Even Parity check in DRAMs with
MR setting. Once it’s enabled via Register in MR5, then DSRAM calculates Parity with
Input ACT_n, RAS_n/A16, CAS_n/A15, WE_n/A14, BG0-BG1, BA0-BA1, A16-A0. Input parity
should be maintained at the rising edge of the clock and at the same time with
command & address with CS_n LOW.
PARITY
ALERT: It has multiple functions, such as CRC error flag or Command and Address Parity
error flag, as an Output signal. If there is an error in CRC, then ALERT_n goes LOW for
the period time interval and goes back HIGH. If there is an error in Command Address
Output Parity Check, then ALERT_n goes LOW for relatively long period until on going DRAM
internal recovery transaction is complete.
ALERT_n
During Connectivity Test mode, this pin functions as an input.
Use of this signal or not is dependent on the system.
SA0-SA1
RFU
Input Device address for the SPD.
Reserved for Future Use. No on DIMM electrical connection is present.
No Connect: No on DIMM electrical connection is present.
NC
VDD1
Supply
Supply
Supply
Power Supply: 1.2 V +/- 0.06 V
Ground
VSS
VTT2
Power Supply : 0.6V
Rev. 1.6 / Jan.2020
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