SN74ALS191ANE4 Texas Instruments Integrated Circuit (Dual-In-Line Packages) In Stock
SN74ALS191ANE4 is a 4-bit synchronous up/down binary counter from the ALS logic family, featuring presettable parallel load, terminal count output (TCO), and operation up to 30 MHz clock frequency in a 16-pin DIP package. It supports bidirectional counting with synchronous preset for flexible sequence generation. Designed for frequency division, event counting, and digital sequencing in industrial and embedded logic circuits.
- Manufacturer
- Texas Instruments
- Package
- Dual-In-Line Packages
- Pin Count
- 16
- Lifecycle
- OBSOLETE
- Datasheet
- SN74ALS191ANE4 Datasheet PDF
- Category
- Integrated Circuit
- Temp Range
- ?°C to 70.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of SN74ALS191ANE4?
- 4-bit synchronous up/down binary counter with bidirectional counting
- 30 MHz maximum clock frequency for high-speed digital applications
- Presettable parallel load input for programmable count sequences
- Terminal Count Output (TCO) enabling easy cascading of multiple counters
- ALS-family logic with low power and fast propagation delay
- 16-pin DIP (R-PDIP-T16) package for breadboard and socket use
What is SN74ALS191ANE4 used for?
The SN74ALS191ANE4 is used in digital frequency division circuits, programmable timers, and event counting stages in industrial control systems where a presettable 4-bit synchronous counter with bidirectional capability is needed. Its TCO output enables seamless cascading of multiple devices to form 8-bit or wider counters for address generation in memory systems or sequence controllers. The device also finds application in educational electronics labs and legacy digital circuit replacement where 74-series ALS compatibility and DIP form factor are required.
What are the specifications of SN74ALS191ANE4?
| YTEOL | 0 |
| Additional Feature | TCO OUTPUT |
| Count Direction | BIDIRECTIONAL |
| Family | ALS |
| JESD-30 Code | R-PDIP-T16 |
| JESD-609 Code | e4 |
| Load Capacitance (CL) | 50pF |
| Load/Preset Input | YES |
| Logic IC Type | BINARY COUNTER |
| Max Frequency@Nom-Sup | 30000000Hz |
| Max I(ol) | 0.008A |
| Mode of Operation | SYNCHRONOUS |
| Number of Bits | 4 |
| Number of Functions | 1 |
| Package Body Material | PLASTIC/EPOXY |
| Package Equivalence Code | DIP16,.3 |
| Package Shape | RECTANGULAR |
| Package Style | IN-LINE |
| Packing Method | TUBE |
| Power Supply Current-Max (ICC) | 22mA |
| Prop. Delay@Nom-Sup | 31ns |
| Propagation Delay (tpd) | 18ns |
| Qualification Status | Not Qualified |
| Supply Voltage-Max (Vsup) | 5.5V |
| Supply Voltage-Min (Vsup) | 4.5V |
| Supply Voltage-Nom (Vsup) | 5V |
| Surface Mount | NO |
| Technology | TTL |
| Temperature Grade | COMMERCIAL |
| Terminal Finish | NICKEL PALLADIUM GOLD |
| Terminal Form | THROUGH-HOLE |
| Terminal Pitch | 2.54mm |
| Terminal Position | DUAL |
| Trigger Type | POSITIVE EDGE |
| fmax-Min | 30MHz |
| Package | Dual-In-Line Packages |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| HTS Code | 8542.39.00.60 |
| Country of Origin | Malaysia, Mexico |
Where can I find the SN74ALS191ANE4 datasheet?
SN74ALS191ANE4 Datasheet DownloadOfficial datasheet from Texas Instruments
What are equivalent replacements for SN74ALS191ANE4?
Compatible alternatives and drop-in replacements for SN74ALS191ANE4:
Binary Counter, ALS Series, Synchronous, Positive Edge Triggered, 4-Bit, Bidirectional, TTL, PDIP16
Binary Counter, ALS Series, Synchronous, Positive Edge Triggered, 4-Bit, Up Direction, TTL, PDIP20
Frequently Asked Questions
What is the maximum clock frequency of the SN74ALS191ANE4, and can it cascade to form wider counters at that speed?
The SN74ALS191ANE4 operates at a maximum clock frequency of 30 MHz, and its Terminal Count Output (TCO) pin is specifically designed to enable cascading of multiple 4-bit counters to create 8-bit, 12-bit, or wider binary counters. When cascaded, the overall counting rate is limited by the propagation delay through the TCO chain, but two devices can typically count at 15 MHz to 20 MHz in an 8-bit ripple-cascade configuration, sufficient for most frequency division and event counting applications.
How does the presettable load feature of the SN74ALS191ANE4 enable programmable count sequences in a timer circuit?
The SN74ALS191ANE4 includes a parallel load input that asynchronously presets all 4 output bits to any value from 0 to 15 when asserted, allowing the counter to reload a specific starting count on each terminal count event. In a timer circuit, this means the divide ratio is programmed by the preset value rather than being fixed at 16, enabling modulo-N counting for any N from 1 to 16. Combined with the TCO output, this supports programmable frequency generation and pulse-width modulation at clock rates up to 30 MHz.
Is the SN74ALS191ANE4 compatible with 5 V TTL logic levels, and can it interface directly with older 74LS-series chips?
Yes, the SN74ALS191ANE4 operates from a 5 V supply and is fully compatible with TTL logic levels, meeting standard VOH and VOL specifications that allow direct interfacing with 74LS, 74S, and 74F family devices without level translation. The ALS (Advanced Low-power Schottky) family provides faster switching than LS while consuming less power, making it a drop-in performance upgrade from 74LS191 in existing 5 V TTL-based PCB designs with 50 pF typical load capacitance compatibility.
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About Texas Instruments
Texas Instruments (TI) is a global semiconductor company headquartered in Dallas, Texas. TI designs and manufactures analog and embedded processing chips used in industrial, automotive, consumer, communications, and enterprise systems.
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