CD74AC191 Datasheet, PDF (1/10 Pages) Texas Instruments – Presettable Synchronous 4-Bit Binary Up/Down Counter

Data sheet acquired from Harris Semiconductor
SCHS243
October 1998
Features
No ^{ROeBcSomOLmEeTnEdePdRROeDpUlaCcTement}
• Buffered Inputs
• Typical Propagation Delay
- 12.8ns at V_CC = 5V, T_A = 25^oC, C_L = 50pF
• Exceeds 2kV ESD Protection MIL-STD-883, Method
3015
• SCR-Latchup-Resistant CMOS Process and Circuit
Design
• Speed of Bipolar FAST™/AS/S with Significantly
Reduced Power Consumption
• Balanced Propagation Delays
• AC Types Feature 1.5V to 5.5V Operation and
Balanced Noise Immunity at 30% of the Supply
• ±24mA Output Drive Current
- Fanout to 15 FAST™ ICs
- Drives 50Ω Transmission Lines
CD74AC191,
CD74ACT191
Presettable Synchronous 4-Bit Binary
Up/Down Counter
Description
The CD74AC191 and CD74ACT191 are asynchronously
presettable binary up/down synchronous counters that utilize
the Harris Advanced CMOS Logic technology. Presetting the
counter to the number on preset data inputs (P0-P3) is
accomplished by setting LOW the asynchronous parallel
load input (PL). Counting occurs when PL is HIGH, Count
Enable (CE) is LOW, and the Up/Down (U/D) input is either
LOW for up-counting or HIGH for down-counting. The
counter is incremented or decremented synchronously with
the LOW-to-HIGH transition of the clock.
When an overflow or underflow of the counter occurs, the
Terminal Count (TC) output, which is LOW during counting,
goes HIGH and remains HIGH for one clock cycle. This out-
put can be used for look-ahead carry in high-speed cascad-
ing (see Figure 12). The TC output also initiates the Ripple
Clock (RC) output which, normally HIGH, goes LOW and
remains LOW for the low-level cascaded using the Ripple
Count output.
Ordering Information
Pinout
PART
NUMBER
CD74AC191E
CD74ACT191E
CD74AC191M
CD74ACT191M
TEMP.
RANGE (^oC)
PACKAGE
0 to 70^oC, -40 to 85, 16 Ld PDIP
-55 to 125
0 to 70^oC, -40 to 85, 16 Ld PDIP
-55 to 125
0 to 70^oC, -40 to 85, 16 Ld SOIC
-55 to 125
0 to 70^oC, -40 to 85, 16 Ld SOIC
-55 to 125
PKG.
NO.
E16.3
E16.3
M16.15
M16.15
NOTES:
1. When ordering, use the entire part number. Add the suffix 96 to
obtain the variant in the tape and reel.
2. Wafer and die for this part number is available which meets all elec-
trical specifications. Please contact your local sales office or Harris
customer service for ordering information.
CD74AC191, CD74ACT191
(PDIP, SOIC)
TOP VIEW
P1 1
Q1 2
Q0 3
CE 4
U/D 5
Q2 6
Q3 7
GND 8
16 V_CC
15 P0
14 CP
13 RC
12 TC
11 PL
10 P2
9 P3
CAUTION: These devices are sensitive to electrostatic discharge. Users should follow proper IC Handling Procedures.
FAST™ is a Trademark of Fairchild Semiconductor.
Copyright © Harris Corporation 1998
1
File Number 1911.1