Datasheet
SDAS210C − DECEMBER 1982 − REVISED JULY 1996
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
POST OFFICE BOX 1443
• HOUSTON, TEXAS 77251−1443
description (continued)
Two outputs are available to perform the cascading function: ripple clock and maximum/minimum count. The
latter output produces a high-level output pulse with a duration approximately equal to one complete cycle of
the clock while the count is minimum (0) counting down or maximum (15) counting up. The ripple-clock output
(RCO
) produces a low-level output pulse under those same conditions, but only while the clock input is low. The
counter easily can be cascaded by feeding the ripple-clock output to the enable input of the succeeding counter
if parallel clocking is used, or to the clock input if parallel enabling is used. The maximum/minimum count
(MAX/MIN) output can be used to accomplish look ahead for high-speed operation.
The SN54ALS191A is characterized for operation over the full military temperature range of −55°C to 125°C.
The SN74ALS191A is characterized for operation from 0°C to 70°C.
logic symbol
†
1,2− / 1,3+
CTRDIV16
M2 [DOWN]
5
M3 [UP]
14
CLK
G4
C5
11
MAX/MIN
12
2(CT=0)Z6
3(CT=15)Z6
13
6,1,4
3
2
6
7
5D
15
A
1
B
10
C
9
D
G1
4
[1]
[2]
[4]
[8]
CTEN
D/U
Q
A
Q
B
Q
C
Q
D
LOAD
RCO
†
This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
Pin numbers shown are for the D, J, and N packages.