1Gb: x4, x8, x16 DDR3 SDRAM
Output Driver Impedance
34 Ohm Output Driver Impedance
The 34Ω driver (MR1[5, 1] = ±1) is the default driver. Unless otherwise stated, all timings
and specifications listed herein apply to the 34Ω driver only. Its impedance RON is de-
fined by the value of the external reference resistor RZQ as follows: RON34 = RZQ/0 (with
nominal RZQ = 24±Ω ±1ꢀ) and is actually 34.3Ω rꢂꢉꢁ
Table 37: 34 Ohm Driver Impedance Characteristics
MR1[5,1]
RON
Resistor
VOUT
Min
0.6
Nom
1.0
1.0
1.0
1.0
1.0
1.0
n/a
Max
1.1
1.1
1.4
1.4
1.1
1.1
10
Unit
RZQ/7
RZQ/7
RZQ/7
RZQ/7
RZQ/7
RZQ/7
%
Notes
0,1
ꢇꢆꢁꢇΩ
RON34(PD)
0.2/VDDQ
0.5/VDDQ
0.8/VDDQ
0.2/VDDQ
0.5/VDDQ
0.8/VDDQ
0.5/VDDQ
0.9
0.9
RON34(PU)
0.9
0.9
0.6
Pull-up/pull-down mismatch (MMPUPD
)
–10%
2
1. Tolerance limits assume RZQ of 240Ω 1% and are applicable after proper ZQ calibra-
tion has been performed at a stable temperature and voltage: VDDQ = VDD; VSSQ = VSS).
Refer to 34 Ohm Output Driver Sensitivity (page 66) if either the temperature or the
voltage changes after calibration.
Notes:
2. Measurement definition for mismatch between pull-up and pull-down (MMPUPD). Meas-
ure both RON(PU) and RON(PD) at 0.5 × VDDQ
:
RON(PU) - RON(PD)
MMPUPD
=
× 100
RON,nom
3. For IT and AT (1Gb only) devices, the minimum values are derated by 6% when the de-
vice operates between –40°C and 0°C (TC).
PDF: 09005aef826aa906
1Gb_DDR3_SDRAM.pdf - Rev. L 03/13 EN
Micron Technology, Inc. reserves the right to change products or specifications without notice.
64
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