AS4CM4EOQ datasheet(9/16 Pages) ALSC

9 / 16 page

AS4C4M4EOQ

AS4C4M4E1Q

3/22/01; v.1.0

Alliance Semiconductor

P. 9 of 16

Notes

1ICC1, ICC3, ICC4, and ICC6 are dependent on frequency.

2ICC1 and ICC4 depend on output loading. Specified values are obtained with the output open.

An initial pause of 200 µs is required after power-up followed by any 8 RAS cycles before proper device operation is achieved. In the case of an internal

refresh counter, a minimum of 8 CAS-before-RAS initialization cycles instead of 8 RAS cycles are required. 8 initialization cycles are required after

extended periods of bias without clocks (greater than 8 ms).

AC Characteristics assume tT = 2 ns. All AC parameters are measured with a load equivalent to two TTL loads and 100 pF, VIL (min) ≥ GND and VIH

(max)

≤ V

CC.

5VIH (min) and VIL (max) are reference levels for measuring timing of input signals. Transition times are measured between VIH and VIL.

Operation within the tRCD (max) limit insures that tRAC (max) can be met. tRCD (max) is specified as a reference point only. If tRCD is greater than the

specified tRCD (max) limit, then access time is controlled exclusively by tCAC.

Operation within the tRAD (max) limit insures that tRAC (max) can be met. tRAD (max) is specified as a reference point only. If tRAD is greater than the

specified tRAD (max) limit, then access time is controlled exclusively by tAA.

Assumes three state test load (5 pF and a 380

Ω Thevenin equivalent).

9Either tRCH or tRRH must be satisfied for a read cycle.

10 tOFF (max) defines the time at which the output achieves the open circuit condition; it is not referenced to output voltage levels. tOFF is referenced from

rising edge of RAS or CAS, whichever occurs last.

11 tWCS, tWCH, tRWD, tCWD and tAWD are not restrictive operating parameters. They are included in the datasheet as electrical characteristics only.

If tWS ≥ tWS (min) and tWH ≥ tWH (min), the cycle is an early write cycle and data out pins will remain open circuit, high impedance, throughout the

cycle. If tRWD ≥ tRWD (min), tCWD ≥ tCWD (min) and tAWD ≥ tAWD (min), the cycle is a read-write cycle and the data out will contain data read from the

selected cell. If neither of the above conditions is satisfied, the condition of the data out at access time is indeterminate.

12 These parameters are referenced to CAS leading edge in early write cycles and to WE leading edge in read-write cycles.

13 Access time is determined by the longest of tCAA or tCAC or tCPA

14 tASC ≥ tCP to achieve tPC (min) and tCPA (max) values.

15 These parameters are sampled and not 100% tested.

16 These characteristics apply to AS4C4M4EOQ 5V devices.

17 These characteristics apply to AS4C4M4E1Q 5V devices.

AC test conditions

Key to switching waveforms

- Access times are measured with output reference levels of VOH =

2.4V and VOL = 0.4V,

VIH = 2.4V and VIL = 0.8V

- Input rise and fall times: 2 ns

100 pF*

R2 = 295

Ω

R1 = 828

Ω

Dout

GND

+5V

Figure A: Equivalent output load

*including scope

and jig capacitance

*including scope

and jig capacitance

50 pF*

R2 = 295

Ω

R1 = 828

Ω

Dout

GND

+3.3V

Figure B: Equivalent output load

(AS4C4M4E0/AS4C4M4E1)

Undefined output/don’t care

Falling input

Rising input

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