EDJ1108BABG, EDJ1116BABG
On-Die Termination (ODT) Levels and I-V Characteristics
On-Die Termination effective resistance RTT is defined by bits A9, A6 and A2 of the MR1 Register.
ODT is applied to the DQ, DM, DQS, /DQS and TDQS, /TDQS (×8 devices only) pins.
A functional representation of the on-die termination is shown in the figure On-Die Termination: Definition of Voltages
and Currents.
The individual pull-up and pull-down resistors (RTTPu and RTTPd) are defined as follows:
Parameter
Symbol
RTTPu
Definition
Conditions
VDDQ − VOUT
IOUT
ODT pull-up resistance
RTTPd is turned off
VOUT
IOUT
ODT pull-down resistance
RTTPd
RTTPu is turned off
Chip in Termination Mode
ODT
VDDQ
IPu
IOut = IPd - IPu
To
other
RTTPu
circuitry
like
RCV,
...
DQ
IOut
RTTPd
IPd
VOut
VSSQ
On-Die Termination: Definition of Voltages and Currents
The value of the termination resistor can be set via MRS command to RTT60 = RZQ/4 (nom) or RTT120 = RZQ/2
(nom).
RTT60 or RTT120 will be achieved by the DDR3 SDRAM after proper IO calibration has been performed.
Tolerances requirements are referred to the ODT DC Electrical Characteristics table.
Measurement Definition for RTT
Apply VIH (AC) to pin under test and measure current I(VIH(AC)), then apply VIL(AC) to pin under test and measure
current I(VIL(AC)) respectively.
VIH(AC) − VIL(AC)
RTT =
I(VIH(AC)) − I(VIL(AC))
Measurement Definition for ∆VM
Measure voltage (VM) at test pin (midpoint) with no load.
2× VM
∆VM =
-1 ×100
VDDQ
Data Sheet E1248E40 (Ver. 4.0)
26
ELPIDA [ ELPIDA MEMORY ]
