Specifications
Battery Backup Characteristics
(Vcc < 4.75 V)
32 Kbyte Static RAM Data Retention and Real-Time Clock
Operation: 1.5 years min., 10 years typ.
Adding 128 Kbyte Static RAM: 1.0 years min., 10 years typ.
STD Bus Loading Characteristics
The unit load is a convenient method for specifying the input and
output drive capability of STD bus cards. In the STD bus systems,
one unit load is equal to one LSTTL load as follows:
•
Maximum high-level input current: 20
µ
A
•
Maximum low-level input current: -400
µ
A
The STD bus unit load reflects input current requirements at worst
case conditions over the recommended supply voltage and ambient
temperature ranges. An output rated at 60 unit loads can drive 60 STD
bus cards having input ratings of one unit load. Tables B-1 and B-2 on
pages B-4 and B-5 include load values for the STD-80 and STD 32
connections, respectively.
B-3