TheTTL - Al Kossow's Bitsavers

PAL20L8A, PAL20R4A, PAL20R6A, PAL20R8A
STANDARD HIGH SPEED PAL CIRCUITS
"T1
CD'
9=
"C
~
o
CC
~
0)
3
3
0).
C"
en
r
o
CC
n'
5V
Vcc /
ov----f
OE
VIH
Vll ______ t
PRELOAD PROCEDURES
OUTPUTS DISABlE~
tdis -+t I+- ~ ~ ten
I ENABLE PRELOAD
....
I
1 -t-r_!O_~_I~-I:
PIN 14 v~~~ ____ ---T
--Ii 1
I I j+--tw1 ---"1
: : I APPlya'n
VIH --- - - - - -+ - - --1- -_.if--,r-r-r-"T"""ii--li
I 1
VERIFY I 100 ns.J
a STATE an II MIN '"1 I
\'-----------
_________ _
VERIFY NEW
VOH
VOl~~~~~~ :
VERIFY a'n + 1
JI ____ ~~~~jL~LJL-~~~~~~========
~ tpd 14-
PIN1 VIH h
(OUTClK) Vll-----------------------' .... -----
preload procedure for registered outputs
Step 1
Step 2
Step 3
Step 4
Step 5
Step 6
Step 7
FIGURE 1. PRELOAD WAVEFORMS
Pin 13 to VIH, Pin 1 to VIL, and VCC to 5 volts.
Pin 14 to VIHH for 10 to 50 microseconds.
Apply VIL for a low and VIH for a high at the Q outputs.
Pin 14 to VIL.
Remove the voltages applied to the outputs.
Pin 13 to VIL.
Check the output states to verify preload.
3-30
TEXAS -I!}
INSTRUMENTS
POST OFFICE BOX 225012 • DALLAS. TEXAS 75265