Datasheet

ODT Characteristics
The ODT effective resistance R
TT
is defined by MR1[9, 6, and 2]. ODT is applied to the
DQ, DM, DQS, DQS#, and TDQS, TDQS# balls (x8 devices only). The ODT target values
and a functional representation are listed in Table 29 and Table 30 (page 51). The indi-
vidual pull-up and pull-down resistors (R
TT(PU)
and R
TT(PD)
) are defined as follows:
• R
TT(PU)
= (V
DDQ
- V
OUT
)/|I
OUT
|, under the condition that R
TT(PD)
is turned off
• R
TT(PD)
= (V
OUT
)/|I
OUT
|, under the condition that R
TT(PU)
is turned off
Figure 19: ODT Levels and I-V Characteristics
R
TT(PU)
R
TT(PD)
ODT
Chip in termination mode
V
DDQ
DQ
V
SSQ
I
OUT
= I
PD
- I
PU
I
PU
I
PD
I
OUT
V
OUT
To
other
circuitry
such as
RCV, . . .
Table 29: On-Die Termination DC Electrical Characteristics
Parameter/Condition Symbol Min Nom Max Unit Notes
R
TT
effective impedance R
TT(EFF)
See Table 30 (page 51) 1, 2
Deviation of VM with respect to
V
DDQ
/2
ΔVM –5 5 % 1, 2, 3
Notes:
1. Tolerance limits are applicable after proper ZQ calibration has been performed at a
stable temperature and voltage (V
DDQ
= V
DD
, V
SSQ
= V
SS
). Refer to ODT Sensitivity
(page 52) if either the temperature or voltage changes after calibration.
2. Measurement definition for R
TT
: Apply V
IH(AC)
to pin under test and measure current
I[V
IH(AC)
], then apply V
IL(AC)
to pin under test and measure current I[V
IL(AC)
]:
R
TT
=
V
IH(AC)
- V
IL(AC)
I(V
IH(AC)
) - I(V
IL(AC)
)
3. Measure voltage (VM) at the tested pin with no load:
ΔVM = – 1
2 × VM
V
DDQ
× 100
4. For IT and AT devices, the minimum values are derated by 6% when the device operates
between –40°C and 0°C (T
C
).
8Gb: x4, x8, x16 DDR3L SDRAM
ODT Characteristics
50
Rev 2.0 June 2016
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