IS43/46TR16640A/AL, IS43/46TR81280A/AL
Integrated Silicon Solution, Inc. – www.issi.com – 3
Rev. 00A
12/12/2011
1.3 Pinout Description - JEDEC Standard
Symbol Type Function
CK, CK# Input Clock: CK and CK# are differential clock inputs. All address and control input signals are sampled
on the crossing of the positive edge of CK and negative edge of CK#.
CKE, (CKE0),
(CKE1)
Input Clock Enable: CKE HIGH activates, and CKE Low deactivates, internal clock signals and device
input buffers and output drivers. Taking CKE Low provides Precharge Power-Down and Self-
Refresh operation (all banks idle), or Active Power-Down (row Active in any bank). CKE is
asynchronous for Self-Refresh exit. After VREFCA and VREFDQ have become stable during the
power on and initialization sequence, they must be maintained during all operations (including
Self-Refresh). CKE must be maintained high throughout read and write accesses. Input buffers,
excluding CK, CK#, ODT and CKE, are disabled during power-down. Input buffers, excluding
CKE, are disabled during Self-Refresh.
CS#, (CS0#),
(CS1#), (CS2#),
(CS3#)
Input Chip Select: All commands are masked when CS# is registered HIGH. CS# provides for external
Rank selection on systems with multiple Ranks. CS# is considered part of the command code.
ODT, (ODT0),
(ODT1)
Input On Die Termination: ODT (registered HIGH) enables termination resistance internal to the DDR3
SDRAM. When enabled, ODT is only applied to each DQ, DQSU, DQSU#, DQSL, DQSL#, DMU,
and DML signal. The ODT pin will be ignored if MR1 and MR2 are programmed to disable RTT.
RAS#. CAS#.
WE#
Input Command Inputs: RAS#, CAS# and WE# (along with CS#) define the command being entered.
DM, (DMU),
(DML)
Input Input Data Mask: 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. For x8 device, the function of DM or TDQS/TDQS# is enabled by Mode Register
A11 setting in MR1.
BA0 - BA2 Input Bank Address Inputs: BA0 - BA2 define to which bank an Active, Read, Write, or Precharge
command is being applied. Bank address also determines which mode register is to be accessed
during a MRS cycle.
A0 - A13 Input Address Inputs: Provide the row address for Active commands and the column address for Read/
Write commands to select one location out of the memory array in the respective bank. (A10/AP
and A12/BC# have additional functions; see below). The address inputs also provide the op-code
during Mode Register Set commands.
A10 / AP Input 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 LOW) or all banks (A10 HIGH). If
only one bank is to be precharged, the bank is selected by bank addresses.
A12 / BC# Input Burst Chop: A12 / BC# is sampled during Read and Write commands to determine if burst chop
(on-the-fly) will be performed. (HIGH, no burst chop; LOW: burst chopped). See command truth
table for details.
RESET# Input Active Low Asynchronous Reset: Reset is active when RESET# is LOW, and inactive when
RESET# is HIGH. RESET# must be HIGH during normal operation. RESET# is a CMOS rail- to-
rail signal with DC high and low at 80% and 20% of VDD, i.e., 1.20V for DC high and 0.30V for
DC low.
DQ Input / Output Data Input/ Output: Bi-directional data bus.
DQU, DQL, DQS,
DQS#, DQSU,
DQSU#, DQSL,
DQSL#
Input / Output Data Strobe: output with read data, input with write data. Edge-aligned with read data, centered
in write data. For the x16, DQSL corresponds to the data on DQL0-DQL7; DQSU corresponds to
the data on DQU0-DQU7. The data strobes DQS, DQSL, and DQSU are paired with differential
signals DQS#, DQSL#, and DQSU#, respectively, to provide differential pair signaling to the
system during reads and writes. DDR3 SDRAM supports differential data strobe only and does
not support single-ended.
TDQS, TDQS# Output Termination Data Strobe: TDQS/TDQS# is applicable for x8 DRAMs only. When enabled via
Mode Register A11 = 1 in MR1, the DRAM will enable the same termination resistance function
on TDQS/TDQS# that is applied to DQS/DQS#. When disabled via mode register A11 = 0 in
MR1, DM/TDQS will provide the data mask function and TDQS# is not used. x16 DRAMs must
disable the TDQS function via mode register A11 = 0 in MR1.
NC No Connect: No internal electrical connection is present.
VDDQ Supply DQ Power Supply: 1.5 V +/- 0.075 V for standard voltage or 1.35V +0.1V, -0.067V for low voltage
VSSQ Supply DQ Ground
