MT40A512M8RH-075EAUT Datasheet, PDF (254/359 Pages) Micron Technology – Automotive DDR4 SDRAM

4Gb: x8, x16 Automotive DDR4 SDRAM
Asynchronous ODT Mode
Asynchronous ODT Mode
Asynchronous ODT mode is selected when the DRAM runs in DLL-off mode. In asyn-
chronous ODT timing mode, the internal ODT command is not delayed by either addi-
tive latency (AL) or the parity latency (PL) relative to the external ODT signal (R_TT(NOM)).
In asynchronous ODT mode, two timing parameters apply: ^tAONAS (MIN/MAX), and
t_{AOFAS (MIN/MAX).}
R_TT(NOM) Turn-on Time
• Minimum R_TT(NOM) turn-on time (^tAONAS [MIN]) is when the device termination cir-
cuit leaves R_TT(Park) and ODT resistance begins to turn on.
• Maximum R_TT(NOM) turn-on time (^tAONAS [MAX]) is when the ODT resistance has
reached R_TT(NOM).
• ^tAONAS (MIN) and ^tAONAS (MAX) are measured from ODT being sampled HIGH.
R_TT(NOM) Turn-off Time
• Minimum R_TT(NOM) turn-off time (^tAOFAS [MIN]) is when the device's termination
circuit starts to leave R_TT(NOM).
• Maximum R_TT(NOM) turn-off time (^tAOFAS [MAX]) is when the on-die termination has
reached R_TT(Park).
• ^tAOFAS (MIN) and ^tAOFAS (MAX) are measured from ODT being sampled LOW.
Figure 202: Asynchronous ODT Timings with DLL Off
T0
T1
T2
T3
T4
T5
T6
Ti
Ti + 1 Ti + 2 Ti + 3 Ti + 4 Ti + 5 Ti + 6
Ta
Tb
diff_CK
CKE
ODT
t_IH
t_IS
t_IH
t_IS
R_TT
R_TT(Park)
t_{AONAS (MAX)}
t_{AONAS (MIN)}
R_TT(NOM)
t_{AONAS (MIN)}
t_{AONAS (MAX)}
Transitioning
CCMTD-1725822587-10418
4gb_auto_ddr4_sdram_z90b.pdf - Rev. D 01/17 EN
254
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