K9W4G08U1M
K9K2G08Q0M
K9K2G08U0M
K9W4G16U1M
K9K2G16Q0M
K9K2G16U0M
FLASH 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 regis-
ter 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(Fig 17). Its value can be
determined by the following guidance.
Rp
ibusy
VCC
1.8V device - VOL : 0.1V, VOH : VCCq-0.1V
3.3V device - VOL : 0.4V, VOH : 2.4V
Ready Vcc
R/B
open drain output
VOH
CL
VOL
Busy
tf
tr
GND
Device
Figure 17. Rp vs tr ,tf & Rp vs ibusy
@ Vcc = 1.8V, Ta = 25°C , CL = 30pF
@ Vcc = 3.3V, Ta = 25°C , CL = 100pF
400
2.4
Ibusy
Ibusy
300n
3m
300n
3m
300
1.2
1.7
200n
100n
2m
1m
200n
100n
200
0.8
2m
1m
120
0.85
60
90
tr
tr
30
100
3.6
0.6
3.6
0.57
1.7
0.43
3.6
2K
3.6
tf
1.7
1.7
2K
tf
1.7
4K
1K
3K
4K
1K
3K
Rp(ohm)
Rp(ohm)
Rp value guidance
VCC(Max.) - VOL(Max.)
1.85V
Rp(min, 1.8V part) =
=
3mA + ΣIL
IOL + ΣIL
VCC(Max.) - VOL(Max.)
3.2V
Rp(min, 3.3V part) =
=
IOL + ΣIL
8mA + 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
38
SAMSUNG [ SAMSUNG ]
