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Texas Instruments SN74LS19ANS
- Part No.:
- SN74LS19ANS
- Manufacturer:
- Texas Instruments
- Category:
- Gates and Inverters
- Package:
- 14-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74LS19ANS.pdf
- Description:
- IC INVERT SCHMITT 6CH 6-INP 14SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,755
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Product details
Overview
SN74LS194AN from Texas Instruments is a 4-bit bidirectional universal shift register IC used for serial-to-parallel and parallel-to-serial data conversion in synchronous digital systems. It features synchronous parallel load, left/right shift, hold, and clear functions with TTL-compatible inputs and outputs, operates at 0°C to 70°C, and uses a 16-pin PDIP package.
For engineers reviewing the SN74LS194AN datasheet, SN74LS194AN pinout, SN74LS194AN application, or SN74LS194AN equivalent, this device is commonly evaluated for legacy industrial control logic, test equipment pattern generation, and discrete-state machine sequencing where deterministic timing and TTL-level compatibility are required.
Technical Context
The SN74LS194AN implements a synchronous 4-bit universal shift register with independent shift-left and shift-right control, parallel load capability on the next clock edge, and asynchronous master reset (CLR). Its operation is fully edge-triggered on the rising edge of the clock input (CLK).
All control inputs - S0, S1, CLR, DS_L (data serial left), DS_R (data serial right), and parallel data inputs D0–D3 - are TTL-compatible with defined VIH/VIL thresholds and drive standard TTL loads. The output stage provides typical VOH = 2.7 V and VOL = 0.5 V at IOL = 8 mA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Function | 4-bit synchronous bidirectional universal shift register with parallel load and asynchronous clear |
| Logic Family | LS-TTL - ensures compatibility with legacy 74LS-series logic and predictable DC noise margins |
| Supply Voltage | VCC = 4.75 V to 5.25 V - requires tightly regulated +5 V rail; not tolerant of wider ranges |
| Propagation Delay | tpd = 25 ns max (CLK to Q) - defines maximum operating frequency of ~20 MHz under typical conditions |
| Operating Temperature | 0°C to +70°C - commercial-grade rating; unsuitable for extended industrial or military environments without derating |
| Output Drive | IOL = 8 mA / IOH = –0.4 mA - supports direct fan-out to 10 standard TTL inputs per output |
Pinout & Package
SN74LS194AN is housed in a 16-pin plastic dual in-line package (PDIP-N), 0.3-inch body width, with through-hole mounting and standard 0.1-inch pin spacing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CLR) | Asynchronous clear input | Active-high reset; forces all Q outputs low regardless of clock or mode inputs |
| 2 (CLK) | Clock input | Rising-edge triggered; all synchronous operations occur on positive transition |
| 3 (S0) | Mode select (LSB) | Together with S1, defines function: 00=hold, 01=shift right, 10=shift left, 11=parallel load |
| 4 (S1) | Mode select (MSB) | See S0; both must be stable before CLK edge for correct mode execution |
| 5 (DS_R) | Serial data input (right shift) | Data shifted into Q0 during right-shift mode; sampled on CLK edge |
| 6 (D0) | Parallel data input (LSB) | Loaded into Q0 when S1S0 = 11 and CLK rises |
| 7 (D1) | Parallel data input | Loaded into Q1 during parallel load; no latching without clock edge |
| 8 (GND) | Ground reference | Signal and power return; must be low-impedance connection for noise immunity |
| 9 (Q0) | Output (LSB) | Reflects stored bit 0; valid after propagation delay from CLK or CLR assertion |
| 10 (Q1) | Output | Bit 1 output; toggles only on clock edges in active mode, not level-sensitive |
| 11 (Q2) | Output | Bit 2 output; maintains state during hold mode; shifts on applicable shift commands |
| 12 (Q3) | Output (MSB) | Bit 3 output; supplies DS_L during left-shift mode when Q3 is shifted out |
| 13 (DS_L) | Serial data input (left shift) | Enters Q3 during left-shift mode; overrides Q3 value on next CLK edge |
| 14 (D2) | Parallel data input | Loaded into Q2 during parallel load; matches D0–D3 pin order |
| 15 (D3) | Parallel data input (MSB) | Loaded into Q3; completes full 4-bit parallel load path |
| 16 (VCC) | Positive supply | +5 V DC supply; bypass capacitor (0.1 µF) recommended near pin for transient suppression |
Key Features
| Feature | Design Value |
|---|---|
| Synchronous bidirectional shifting | Enables flexible data routing in ring counters, sequence generators, and pipeline buffers without external gating |
| Parallel load capability | Allows immediate initialization of register contents from external bus or latch outputs on single clock edge |
| Asynchronous master clear | Provides deterministic reset independent of clock timing - critical for system startup and fault recovery |
| TTL-compatible I/O levels | Guarantees interoperability with legacy 74LS, 74S, and 74F logic families without level-shifting circuitry |
| Standard 16-pin PDIP footprint | Supports hand-soldering, socket-based prototyping, and drop-in replacement in existing through-hole designs |
Applications
| Industrial Control Sequencing | Test Pattern Generation |
|---|---|
|
Use Scenario: A programmable logic controller uses discrete timing stages to cycle through valve actuation sequences in chemical processing. IC Role / Device Role / Timing Role: SN74LS194AN serves as a 4-stage sequencer register, clocked by a 1 Hz timer to advance states and drive relay drivers. Use Value: Enables deterministic, glitch-free state transitions with minimal external logic - reducing PCB area versus microcontroller-based solutions. |
Use Scenario: Automated test equipment applies known stimulus patterns to digital ASICs during production screening. IC Role / Device Role / Timing Role: SN74LS194AN generates repeating 4-bit test vectors (e.g., 0001 → 0010 → 0100 → 1000) via right-shift mode with feedback. Use Value: Delivers precise, repeatable patterns synchronized to tester clock - eliminating software overhead and jitter in hardware-based test benches. |
| Legacy Instrumentation Data Buffering | Discrete-State Machine Implementation |
|
Use Scenario: An analog multimeter digitizes voltage samples and serially transmits them to an LCD driver IC. IC Role / Device Role / Timing Role: SN74LS194AN converts parallel ADC output bits into serial stream using shift-right mode and external clock. Use Value: Reduces interconnect count between ADC and display controller - simplifying layout and improving noise immunity over wide parallel buses. |
Use Scenario: A vending machine controller tracks coin insertion states using hardwired logic instead of firmware. IC Role / Device Role / Timing Role: SN74LS194AN implements a 4-bit state register, updated on each coin pulse to encode accumulated value (e.g., $0.25, $0.50, $0.75, $1.00). Use Value: Provides fully deterministic, radiation-tolerant state storage without volatile memory or clock-domain crossing concerns. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 4-bit universal shift register applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS194AD | SOIC-16 package; RoHS-compliant NiPdAu lead finish; MSL Level-1 rating; same electrical specs | Suitable for surface-mount production; not socket-compatible; requires reflow assembly | Select SN74LS194AD for automated PCB assembly; SN74LS194AN remains preferred for prototyping, repair, or through-hole legacy systems. |
| SN54LS194AJ | CDIP-16 package; military-grade (-55°C to +125°C); non-RoHS SNPB finish; identical logic behavior | Required for aerospace/defense applications with extended temperature and reliability validation | Choose SN54LS194AJ only when MIL-PRF-38535 qualification and extended temperature range are contractually mandated. |
Compared with SN74LS194AD and SN54LS194AJ, the SN74LS194AN offers optimal balance of through-hole serviceability, commercial temperature compliance, and direct compatibility with legacy 74LS design libraries - making it the default choice for maintenance, education, and cost-sensitive industrial upgrades.
Availability
SN74LS194AN is available at Aetrix Electronics and suitable for industrial control sequencing, test pattern generation, legacy instrumentation buffering, and discrete-state machine implementation requiring stable component supply across long-lifecycle programs.
Supply support for SN74LS194AN includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Texas Instruments is a U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic ICs with broad industrial, automotive, and consumer reach.
The SN74LS194A family was developed in the 1970s to provide standardized, TTL-compatible universal shift register functionality for discrete digital system design - emphasizing reliability, interoperability, and ease of integration in non-microprocessor-based logic systems.
FAQ
What is the maximum clock frequency supported by the SN74LS194AN?
The SN74LS194AN has a maximum clock frequency of approximately 20 MHz under typical conditions, derived from its 25 ns maximum propagation delay (tpd) from CLK to Q output. This assumes VCC = 5 V, TA = 25°C, and standard TTL load conditions. System-level timing must account for setup/hold times of control inputs relative to CLK, and actual achievable frequency may be lower in noisy or high-fanout configurations.
Does the SN74LS194AN support asynchronous shifting?
No, the SN74LS194AN does not support asynchronous shifting. All register operations - including shift-left, shift-right, parallel load, and hold - are strictly synchronous to the rising edge of the CLK input. The only asynchronous function is the active-high CLR input, which immediately resets all Q outputs to logic low regardless of clock state.
Can the SN74LS194AN be used in place of the SN74LS194AD in an existing design?
The SN74LS194AN and SN74LS194AD share identical logic functionality, DC electrical specifications, and AC timing parameters. However, they differ in package (PDIP vs. SOIC), lead finish (NIPDAU vs. NIPDAU), and assembly method. Direct substitution requires mechanical redesign: SN74LS194AN cannot be soldered onto an SOIC footprint, and SN74LS194AD lacks through-hole leads for socket use.
What is the purpose of the DS_L and DS_R pins on the SN74LS194AN?
DS_L (pin 13) and DS_R (pin 5) are dedicated serial data inputs for left-shift and right-shift modes, respectively. During left-shift, DS_L feeds the new MSB into Q3; during right-shift, DS_R feeds the new LSB into Q0. These pins allow continuous serial data flow without disturbing parallel inputs, enabling ring counter or linear feedback shift register configurations.
Is the SN74LS194AN RoHS compliant?
Yes, the SN74LS194AN is RoHS compliant, as confirmed by Texas Instruments' packaging documentation. It uses NiPdAu (NIPDAU) lead finish and meets EU Directive 2011/65/EU requirements. The "Yes" RoHS designation appears in TI's official packaging addendum for this part number, distinguishing it from military variants like SN54LS194AJ that use SnPb (SNPB) finish.
SN74LS19ANS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LS
- Package/Case:
- 14-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Inverter
- Number of Circuits:
- 6
- Number of Inputs:
- 6
- Features:
- Schmitt Trigger
- Voltage - Supply:
- 4.75V ~ 5.25V
- Current - Quiescent (Max):
- 30 mA
- Current - Output High, Low:
- 400µA, 8mA
- Input Logic Level - Low:
- 1.25V
- Input Logic Level - High:
- 2.15V
- Max Propagation Delay @ V, Max CL:
- 30ns @ 5V, 15pF
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SO
SN74LS19ANS FAQ
1.How can I place an order for SN74LS19ANS through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LS19ANS on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SN74LS19ANS reliable?
The price and inventory of SN74LS19ANS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS19ANS is usually 5 days.
3.What payment methods are accepted for SN74LS19ANS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS19ANS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LS19ANS?
SN74LS19ANS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LS19ANS order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SN74LS19ANS?
For technical support, including SN74LS19ANS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS19ANS requirements.
6.How does Aetrix verify that SN74LS19ANS is sourced from the original manufacturer or authorized distributors?
All SN74LS19ANS products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SN74LS19ANS meets industry standards.
7.What is the process for return or replacement of SN74LS19ANS?
All SN74LS19ANS units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS19ANS, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SN74LS19ANS part is unused and in its original packaging.
Return procedure for SN74LS19ANS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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