K5D5657ACM Datasheet, PDF (29/74 Pages) Samsung semiconductor – 256Mb NAND and 256Mb Mobile SDRAM

K5D5657ACM-F015
PrelAimdvinanacrye
MCP MEMORY
READY/BUSY
The device has a R/B output that provides a hardware method of indicating the completion of a page program, erase and random
read completion. The R/B pin is normally high but transitions to low after program or erase command is written to the command reg-
ister or random read is started after address loading. It returns to high when the internal controller has finished the operation. The pin
is an open-drain driver thereby allowing two or more R/B outputs to be Or-tied. Because pull-up resistor value is related to tr(R/B) and
current drain during busy(ibusy) , an appropriate value can be obtained with the following reference chart. Its value can be deter-
mined by the following guidance.
Vccqn
GND
Rp _ibusy
R/Bn
open drain output
Ready Vccqn
0.4V
tf
Busy
Device
Vccqn-0.4V
tr
Figure 13. Rp vs tr ,tf & Rp vs ibusy
@ Vcc = 1.8V, Ta = 25°C , C_L = 30pF
300n
200n
100n
Ibusy
3m
1.7
2m
tr ^0.85
90
120
30
60
0.57
0.43
1m
1.7 _tf
1.7
1.7
1.7
1K
2K
3K
4K
Rp(ohm)
Rp value guidance
Vccq(Max.) - VOL(Max.)
Rp(min, 1.8V part) =
=
IOL + ΣIL
1.9V
3mA + ΣIL
where IL is the sum of the input currents of all devices tied to the R/B pin.
Rp(max) is determined by maximum permissible limit of tr
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Revision 0.1
September 2003