HYB18T512161BF Datasheet, PDF (32/41 Pages) Qimonda AG – 512-Mbit x16 DDR2 SDRAM

Internet Data Sheet
HYB18T512161BF–20/22/25/28/33
512-Mbit Double-Data-Rate-Two SDRAM
17) The maximum limit for the t_WPST parameter is not a device limit. The device operates with a greater value for this parameter, but system
performance (bus turnaround) degrades accordingly.
18) WR must be programmed to fulfill the minimum requirement for the t_WR timing parameter, where WR_MIN[cycles] = t_WR(ns)/t_CK(ns) rounded
up to the next integer value. t_DAL = WR + (t_RP/t_CK). For each of the terms, if not already an integer, round to the next highest integer. t_CK
refers to the application clock period. WR refers to the WR parameter stored in the MRS.
19) Minimum t_WTR is two clocks when operating the DDR2-SDRAM at frequencies ≤ 200 MHz.
20) User can choose two different active power-down modes for additional power saving via MRS address bit A12. In “standard active power-
down mode” (MR, A12 = “0”) a fast power-down exit timing t_XARD can be used. In “low active power-down mode” (MR, A12 =”1”) a slow
power-down exit timing t_XARDS has to be satisfied.
5.7.3
ODT AC Electrical Characteristics
Symbol
TABLE 31
ODT AC Electrical Characteristics and Operating Conditions for all bins
Parameter / Condition
Unit Note
Min.
Max.
t_AOND
t_AON
ODT turn-on delay
ODT turn-on
2
t_AC.MIN
2
t_AC.MAX + 0.7 ns
t_CK
ns ¹⁾
t_AONPD
ODT turn-on (Power-Down Modes)
t_AC.MIN + 2 ns
2 t_CK + t_AC.MAX + 1 ns
ns
t_AOFD
t_AOF
ODT turn-off delay
ODT turn-off
2.5
t_AC.MIN
2.5
t_AC.MAX + 0.6 ns
t_CK
ns ²⁾
t_AOFPD
ODT turn-off (Power-Down Modes)
t_AC.MIN + 2 ns
2.5 t_CK + t_AC.MAX + 1 ns
ns
t_ANPD
ODT to Power Down Mode Entry Latency
3
—
t_CK
t_AXPD
ODT Power Down Exit Latency
8
—
t_CK
1) ODT turn on time min. is when the device leaves high impedance and ODT resistance begins to turn on. ODT turn on time max is when
the ODT resistance is fully on. Both are measure from t_AOND.
2) ODT turn off time min. is when the device starts to turn off ODT resistance. ODT turn off time max is when the bus is in high impedance.
Both are measured from t_AOFD.
Rev. 1.43, 2006-11
32
03292006-L40N-L04G