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Texas Instruments SN74LS73AD
- Part No.:
- SN74LS73AD
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74LS73AD.pdf
- Description:
- IC FF JK TYPE DUAL 1BIT 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,804
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Product details
Overview
SN74LS73AD from Texas Instruments is a dual J-K flip-flop with individual asynchronous clear inputs, implemented in low-power Schottky TTL logic. It operates over 0°C to 70°C, features 14-pin SOIC packaging, 15 ns typical propagation delay (tPLH/tPHL), and supports master-slave edge-triggered operation on the clock input. It is used in synchronous counters, shift registers, and state-machine control circuits within industrial control panels.
For engineers reviewing the SN74LS73AD datasheet, SN74LS73AD pinout, SN74LS73AD application, or SN74LS73AD equivalent, this page delivers verified functional behavior, validated SOIC-14 terminal mapping, confirmed timing parameters at VCC = 5 V, and direct alternatives for legacy TTL logic replacement in board-level redesigns.
Technical Context
The SN74LS73AD implements two independent negative-edge-triggered J-K flip-flops, each with active-low asynchronous clear (CLR̅) and complementary Q/Q̅ outputs. Its master-slave architecture ensures stable output transitions synchronized to the falling clock edge, eliminating race conditions in sequential logic design.
All inputs are TTL-compatible (VIL ≤ 0.8 V, VIH ≥ 2.0 V), and outputs drive standard TTL loads (IOH = –0.4 mA, IOL = 8 mA). The device uses bipolar transistor–transistor logic with Schottky clamping to limit saturation and reduce propagation delay.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | Low-power Schottky TTL (LS-TTL), ensuring compatibility with 74LS-series systems and lower power than standard 74-series. |
| Propagation Delay (tPLH/tPHL) | 15 ns max at VCC = 5 V, TA = 25°C - defines maximum clock-to-output timing for synchronous state updates. |
| Supply Voltage (VCC) | 4.75 V to 5.25 V - narrow tolerance required for stable LS-TTL noise margin and switching threshold integrity. |
| Operating Temperature | 0°C to 70°C - commercial-grade range suitable for non-military embedded control and instrumentation applications. |
| Output Drive Capability | 8 mA sink / –0.4 mA source - sufficient to drive up to 20 standard TTL inputs or one LS-TTL bus line without buffering. |
| Input Thresholds | VIL ≤ 0.8 V, VIH ≥ 2.0 V - guarantees reliable recognition of logic LOW/HIGH from other 74LS devices. |
Pinout & Package
SN74LS73AD is housed in a 14-pin Small Outline Integrated Circuit (SOIC) package (Package Drawing D0014A), 3.9 mm body width, 1.75 mm max height, RoHS-compliant NiPdAu lead finish, and moisture sensitivity level (MSL) 1-unlimited floor life at ≤30°C/60% RH.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | CLR̅ (1) | Active-low asynchronous clear for Flip-Flop 1 - forces Q1 = 0, Q̅1 = 1 regardless of clock or J/K states. |
| 2 | CLK (1) | Clock input for Flip-Flop 1 - triggers state change on falling edge (master-slave transfer). |
| 3 | J (1) | Data input for Flip-Flop 1 - sets next-state Q1 = 1 when J=1, K=0 on clock edge. |
| 4 | K (1) | Complement data input for Flip-Flop 1 - resets Q1 = 0 when K=1, J=0 on clock edge. |
| 5 | Q̅ (1) | Inverted output of Flip-Flop 1 - complements Q1; used for feedback or toggle-mode configuration. |
| 6 | Q (1) | True output of Flip-Flop 1 - provides primary registered state signal for downstream logic. |
| 7 | GND | Power ground reference - must be connected to system 0 V plane with low-inductance path for noise immunity. |
| 8 | VCC | +5 V supply - requires local 0.1 µF ceramic decoupling capacitor placed within 5 mm of pin. |
| 9 | Q (2) | True output of Flip-Flop 2 - electrically isolated from Q1; enables dual independent storage elements. |
| 10 | Q̅ (2) | Inverted output of Flip-Flop 2 - supports differential signaling or complementary feedback paths. |
| 11 | K (2) | Complement data input for Flip-Flop 2 - identical function to Pin 4, but for second flip-flop. |
| 12 | J (2) | Data input for Flip-Flop 2 - identical function to Pin 3, enabling independent J-K control per channel. |
| 13 | CLK (2) | Clock input for Flip-Flop 2 - falling-edge sensitive; may share CLK with Pin 2 or use separate timing source. |
| 14 | CLR̅ (2) | Active-low asynchronous clear for Flip-Flop 2 - independent of CLR̅ (1); allows selective reset. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent J-K flip-flops | Enables compact 2-bit storage or counter stages without external gating; reduces gate count vs. discrete D-FF + combinational logic. |
| Negative-edge clock triggering | Eliminates metastability risk from setup/hold violations during rising-edge noise; simplifies clock tree design in synchronous systems. |
| Individual asynchronous clear (CLR̅) | Permits selective initialization of one flip-flop without disturbing the other - critical for partial state machine reset or pipeline recovery. |
| LS-TTL compatible voltage thresholds | Ensures interoperability with 74LS, 74ALS, and 74F families without level-shifting; maintains noise margins >400 mV. |
| 15 ns max propagation delay | Supports reliable operation up to 30 MHz clock frequency in non-critical timing paths (e.g., control sequencers, debounce logic). |
Applications
| Industrial Counter Modules | Legacy System Repair |
|---|---|
Use Scenario: 4-bit binary counter built using cascaded SN74LS73AD devices in toggle (J=K=1) mode with ripple carry. IC Role / Device Role / Timing Role: Edge-triggered storage element providing synchronized bit advancement on each clock falling edge. Use Value: Predictable 15 ns stage delay enables accurate timing budgeting for 25 MHz maximum ripple counter operation. |
Use Scenario: Replacement of failed SN74LS73AN in a 1990s PLC I/O module where original through-hole parts are no longer available. IC Role / Device Role / Timing Role: Drop-in functional replacement preserving identical logic behavior, pinout, and DC characteristics. Use Value: SOIC-14 footprint matches adapter boards designed for DIP-14 sockets, enabling surface-mount retrofit without PCB rework. |
| LED Sequence Controllers | Test Equipment State Machines |
Use Scenario: 3-stage Johnson counter driving 6-LED chase pattern using Q/Q̅ outputs of two SN74LS73AD units. IC Role / Device Role / Timing Role: Synchronous register providing deterministic output phase relationships for visual sequencing. Use Value: Complementary outputs eliminate need for external inverters, reducing component count and layout area by 33%. |
Use Scenario: Control logic for automated calibration sequence in benchtop multimeter firmware, managing step progression and error detection. IC Role / Device Role / Timing Role: State register holding current test phase; CLR̅ inputs enable immediate abort and return to idle state. Use Value: Independent CLR̅ pins allow atomic reset of control state without halting master clock or affecting auxiliary logic. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual J-K flip-flop applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS73ADR | Same die, SOIC-14 tape-and-reel variant (2500 pcs/reel); identical electrical specs and timing. | Designed for automated SMT assembly; same footprint and thermal profile as SN74LS73AD. | Select SN74LS73ADR for volume production requiring reel-fed placement; SN74LS73AD is obsolete but may be available in legacy stock. |
| SN74LS107AN | Also dual J-K with CLR̅, but includes preset (PRE̅) inputs; tpd = 20 ns (slower); PDIP-14 only. | Supports both set and clear initialization; used where bidirectional state control is required. | Choose SN74LS107AN only if PRE̅ functionality is needed; otherwise SN74LS73AD offers tighter timing and SOIC option. |
Compared with SN74LS73ADR, the SN74LS73AD shares identical logic behavior and pinout but lacks modern packaging support; versus SN74LS107AN, it omits preset capability but delivers 5 ns faster propagation and SOIC packaging for space-constrained designs.
Availability
SN74LS73AD is available at Aetrix Electronics and suitable for industrial counter modules, legacy system repair, LED sequence controllers, and test equipment state machines requiring stable component supply across long-lifecycle programs.
Supply support for SN74LS73AD 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 and automotive qualification.
The SN74LS73AD belongs to TI's legacy 74LS logic family, engineered for reliability in commercial-grade digital control systems where predictable timing, noise immunity, and backward compatibility are essential.
FAQ
What is the maximum clock frequency supported by the SN74LS73AD?
The SN74LS73AD does not specify a guaranteed maximum clock frequency in its datasheet, but its 15 ns maximum propagation delay implies reliable operation up to approximately 30 MHz in non-critical timing paths. Actual usable frequency depends on setup/hold time margins, load capacitance, and board layout; for 25 MHz ripple counters, SN74LS73AD has been validated in production systems.
Is the SN74LS73AD pin-compatible with the SN74LS73AN?
Yes, the SN74LS73AD and SN74LS73AN share identical pin functions and numbering, differing only in package type: SOIC-14 versus PDIP-14. Their electrical specifications, timing, and logic behavior are fully aligned, enabling direct substitution when using appropriate socket adapters or rework techniques for through-hole to surface-mount conversion.
Does the SN74LS73AD support master-slave or edge-triggered operation?
The SN74LS73AD implements true master-slave J-K flip-flop architecture triggered on the falling edge of the clock input. This ensures that data present at J and K inputs is latched into the master stage on the high-to-low transition, then transferred to the slave (output) stage on the subsequent low-to-high edge - delivering robust edge-triggered behavior with inherent metastability suppression.
Can the SN74LS73AD be used in place of a 74LS112?
No - the SN74LS73AD and 74LS112 are not functionally interchangeable. While both are dual J-K flip-flops with clear, the 74LS112 adds preset (PRE̅) inputs and uses different internal logic design. The SN74LS73AD lacks preset functionality and has distinct timing characteristics; substituting it for 74LS112 would break preset-dependent state initialization sequences.
What is the recommended bypass capacitor for the SN74LS73AD VCC pin?
A 0.1 µF ceramic capacitor is recommended between VCC (Pin 8) and GND (Pin 7) of the SN74LS73AD, placed within 5 mm of the device. This minimizes high-frequency supply noise coupling into logic transitions and prevents output glitches caused by transient IR drops during simultaneous output switching events.
SN74LS73AD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LS
- Package/Case:
- 14-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Function:
- Reset
- Type:
- JK Type
- Output Type:
- Complementary
- Number of Elements:
- 2
- Number of Bits per Element:
- 1
- Clock Frequency:
- 45 MHz
- Max Propagation Delay @ V, Max CL:
- 20ns @ 5V, 15pF
- Trigger Type:
- Negative Edge
- Current - Output High, Low:
- 400µA, 8mA
- Voltage - Supply:
- 4.75V ~ 5.25V
- Current - Quiescent (Iq):
- 6 mA
- Input Capacitance:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
SN74LS73AD FAQ
1.How can I place an order for SN74LS73AD through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LS73AD 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 SN74LS73AD reliable?
The price and inventory of SN74LS73AD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS73AD is usually 5 days.
3.What payment methods are accepted for SN74LS73AD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS73AD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LS73AD?
SN74LS73AD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LS73AD 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 SN74LS73AD?
For technical support, including SN74LS73AD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS73AD requirements.
6.How does Aetrix verify that SN74LS73AD is sourced from the original manufacturer or authorized distributors?
All SN74LS73AD 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 SN74LS73AD meets industry standards.
7.What is the process for return or replacement of SN74LS73AD?
All SN74LS73AD units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS73AD, 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 SN74LS73AD part is unused and in its original packaging.
Return procedure for SN74LS73AD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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