W3EG6462S-D3 Datasheet, PDF (10/13 Pages) White Electronic Designs Corporation – 512MB - 2x32Mx64 DDR SDRAM UNBUFFERED

White Electronic Designs
W3EG6462S-D3
-JD3
ADVANCED
33. The voltage levels used are derived from a mini-mum VCC level and the referenced
test load. In practice, the voltage levels obtained from a properly terminated bus will
provide significantly different voltage values.
34. VIH overshoot: VIH (MAX) = VCCQ + 1.5V for a pulse width ≤ 3ns and the pulse width
can not be greater than 1/3 of the cycle rate. VIL undershoot: VIL (MIN) = -1.5V for a
pulse width ≤ 3ns and the pulse width can not be greater than 1/3 of the cycle rate.
35. VCC and VCCQ must track each other.
36. tHZ (MAX) takes precedence over tDQSCK (MAX) + tRPST (MAX) condition. tLZ (MIN)
will prevail over tDQSCK (MIN) + tRPRE (MAX) condition.
37. tRPST end point and tRPRE begin point are not referenced to a specific voltage level
but specify when the device output is no longer driving (tRPST), or begins driving
(tRPRE).
38. During initialization, VCCQ, VTT, and VREF must be equal to or less than VCC + 0.3V.
Alternatively, VTT may be 1.35V maximum during power up, even if VCC/VCCQ are
0V, provided a minimum of 42Ω of series resistance is used between the VTT
supply and the input pin.
39. For 403, 335, 262, 263 and 265 speed grades, IDD3N is specified to be 35mA per
DDR SDRAM at 100 MHz.
40. The current part operates below the slowest JEDEC operating frequency of
83 MHz. As such, future die may not reflect this option.
41. Random addressing changing and 50 percent of data changing at every transfer.
42. Random addressing changing and 100 percent of data changing at every transfer.
43. CKE must be active (high) during the entire time a refresh command is executed.
That is, from the time the AUTO REFRESH command is registered, CKE must be
active at each rising clock edge, until tREF later.
44. IDD2N specifies the DQ, DQS, and DM to be driven to a valid high or low logic level.
IDD2Q is similar to IDD2F except IDD2Q specifies the address and control inputs to
remain stable. Although IDD2F, IDD2N, and IDD2Q are similar, IDD2F is “worst case.”
45. Whenever the operating frequency is altered, not including jitter, the DLL is required
to be reset. This is followed by 200 clock cycles.
46. Leakage number reflects the worst case leakage possible through the module pin,
not what each memory device contributes.
47. When an input signal is HIGH or LOW, it is defined as a steady state logic HIGH or
logic LOW.
48. The 403 speed grade will operate with tRAS (MIN) = 40ns and tRAS (MAX) =
120,000ns at any slower frequency.
May 2005
Rev. 4
10
White Electronic Designs Corporation • [phone] • www.wedc.com