EDJ4216BASE Datasheet, PDF (25/146 Pages) Elpida Memory – 4G bits DDR3 SDRAM

EDJ4216BASE
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 and /DQS 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
ODT pull-up resistance
Symbol
RTTPu
ODT pull-down resistance RTTPd
Definition
VDDQ − VOUT
⏐IOUT⏐
VOUT
⏐IOUT⏐
Conditions
RTTPd is turned off
RTTPu is turned off
Chip in Termination Mode
ODT
To
other
circuitry
like
RCV,
...
I_Pu
RTT_Pu
RTT_Pd
I_Pd
VDDQ
I_Out = I_Pd - I_Pu
DQ
I_Out
V_Out
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 I/O 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.
RTT
=
VIH(AC)
I(VIH(AC))
− VIL(AC)
− I(VIL(AC))
Measurement Definition for ΔVM
Measure voltage (VM) at test pin (midpoint) with no load.
ΔVM
=

2 × VM
VDDQ
-
1 _{}
×
100
Data Sheet E1646E41 (Ver. 4.1)
25