![](http://datasheet.mmic.net.cn/110000/IMISC643AYB_datasheet_3494102/IMISC643AYB_10.png)
SC643
I
2C Clock Generator for 3 DIMM, Pentium
II Designs
Approved Product
INTERNATIONAL MICROCIRCUITS, INC. 525 LOS COCHES ST.
Rev.1.6
6/20/97
MILPITAS, CA 95035. TEL: 408-263-6300. FAX 408-263-6571
Page 10 of 12
TYPE 4 BUFFER CHARACTERISTICS FOR SDRAM(0:11)
Characteristic
Symbol
Min
Typ
Max
Units
Conditions
Pull-Up Current
IOH
-94
-134
-188
mA
Vout = 1.0 V
Pull-Up Current
IOH
-74
-106
-148
mA
Vout = 2.0 V
Pull-Down Current
IOL
83
119
167
mA
Vout = 1.2 V
Pull-Down Current
IOL
26
38
53
mA
Vout = 0.3 V
Rise/Fall Time Min
Between 0.4 V and 2.4 V
TRFmin
0.5
-
nS
20 pF Load
Rise/Fall Time Max
Between 0.4 V and 2.4 V
TRFmax
-
2.0
nS
30 pF Load
VDD = VDDQ3 =3.3V
±5%, VDDQ2 = 2.5 + 5%, TA = 0C to +70C
TYPE 5 BUFFER CHARACTERISTICS FOR PCICLK(0:5,F)
Characteristic
Symbol
Min
Typ
Max
Units
Conditions
Pull-Up Current
IOH
-94
-134
-188
mA
Vout = 1.0 V
Pull-Up Current
IOH
-74
-106
-148
mA
Vout = 2.0 V
Pull-Down Current
IOL
83
119
167
mA
Vout = 1.2 V
Pull-Down Current
IOL
26
38
53
mA
Vout = 0.3 V
Rise/Fall Time Min
Between 0.4 V and 2.4 V
TRFmin
0.5
-
nS
15 pF Load
Rise/Fall Time Max
Between 0.4 V and 2.4 V
TRFmax
-
2.0
nS
30 pF Load
VDD = VDDQ3 =3.3V
±5%, VDDQ2 = 2.5 + 5%, TA = 0C to +70C
APPLICATION NOTE FOR SELECTION ON BIDIRECTIONAL PINS
Pins 7, 8, 10, 25, and 26are bidirectional pins and are used for selecting different functions in this device (see Pin description, Pages
2&3). During power-up of the SC643, these pins are in input mode (see Fig1, page3), therefore, they are considered input select
pins. Internal to the IC, these pins have a large value pull-up each (100K
), therefore, a selection “1” is the default. If a selection
“0” is desired, then a direct connection to ground through a 10K
resistor should be implemented as shown in Fig.3. Please note
the selection resistor (10K
) is placed before the Damping resistor (Rd) close to the pin.
Fig. 3
IMISC643
Rd
To load
Pins 7, 8, 10, 15, 25, 26, and 46
10K