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Texas Instruments SN74LS273DW
- Part No.:
- SN74LS273DW
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74LS273DW.pdf
- Description:
- IC FF D-TYPE SNGL 8BIT 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,874
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Product details
Overview
SN74LS273DW from Texas Instruments is an octal D-type positive-edge-triggered flip-flop with asynchronous clear, implemented in low-power Schottky TTL logic. It features eight independent D inputs, eight Q outputs, a shared clock (CLK), and a direct-clear (CLR) input. Each flip-flop transfers data on the rising edge of CLK while CLR forces all Q outputs low independently of CLK. It is used in synchronous digital systems such as buffer registers and pattern generators operating at up to 30 MHz.
For engineers reviewing the SN74LS273DW datasheet, SN74LS273DW pinout, SN74LS273DW application, or SN74LS273DW equivalent, this page delivers verified electrical parameters, SOIC-20 package details, timing behavior under 5 V operation, and real-world register-level use cases - all grounded in TI's SDLS090 datasheet and production documentation.
Technical Context
The SN74LS273DW implements eight edge-triggered D latches with common clock and asynchronous clear, using bipolar TTL circuitry optimized for speed and power efficiency. Its logic diagram confirms individual D-to-Q paths with internal C1/R latch structures per stage, buffered CLK and CLR inputs, and single-rail (non-complementary) outputs.
It operates within 4.75–5.25 V supply range and supports guaranteed clock frequencies from DC to 30 MHz (typical max 40 MHz). Propagation delays are specified at 17–27 ns (tPLH/tPHL), with setup time (20 ns) and hold time (5 ns) referenced to the rising CLK edge - confirming strict synchronous timing discipline for register file and state machine applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | Low-power Schottky TTL (LS), compatible with standard TTL voltage thresholds and drive strength |
| Supply Voltage Range | 4.75 V to 5.25 V - ensures stable operation in 5 V digital systems with ±5% rail tolerance |
| Max Clock Frequency | 30 MHz guaranteed, 40 MHz typical - defines maximum synchronous update rate for register banks |
| Propagation Delay | 17–27 ns (CLK→Q or CLR→Q) - determines minimum cycle time in pipelined or cascaded register designs |
| Input Thresholds | VIH = 2.0 V min, VIL = 0.8 V max - ensures reliable interfacing with 5 V CMOS and TTL output stages |
| Output Drive | IOL = 4 mA min (low), IOH = –400 µA min (high) - sufficient to drive multiple LS/TTL inputs without fanout limitation |
| Power Dissipation | 17–27 mA ICC total (≈2.5 mW per flip-flop) - enables dense register arrays without thermal concern in ambient conditions |
Pinout & Package
SN74LS273DW is housed in a 20-pin SOIC (DW) package, 7.5 mm wide, with 1.27 mm pitch and 2.65 mm max height. Pin 1 is marked by a beveled corner or notch orientation per JEDEC MS-013.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | CLR | Asynchronous active-low clear - forces all eight Q outputs low regardless of clock state |
| 2–9 | 1D–8D | Eight independent data inputs - each controls corresponding Q output on next CLK rising edge |
| 10 | GND | Ground reference for all internal circuitry and I/O |
| 11–18 | 1Q–8Q | Eight non-inverted registered outputs - retain state between clock edges |
| 19 | CLK | Positive-edge-triggered clock - samples all D inputs simultaneously on rising transition |
| 20 | VCC | +5 V power supply - must be decoupled locally to suppress switching noise |
Key Features
| Feature | Design Value |
|---|---|
| Octal D-type flip-flops with common clock | Enables compact 8-bit register storage without external gating or clock distribution logic |
| Direct asynchronous clear (CLR) | Allows immediate reset of entire register bank without waiting for clock edge or affecting other system timing |
| Buffered clock and clear inputs | Reduces loading on upstream drivers and improves noise immunity in high-density PCB layouts |
| Single-rail TTL-compatible outputs | Supports direct connection to LS, S, or standard TTL loads without level-shifting or pull-up resistors |
| Guaranteed 30 MHz operation over 0°C to 70°C | Validates use in commercial-grade embedded controllers, test equipment, and industrial logic modules |
Applications
| Buffer/Storage Register | Shift Register Stage |
|---|---|
Use Scenario: Holding parallel data from a microprocessor data bus during memory read/write cycles. IC Role / Device Role / Timing Role: Acts as an 8-bit transparent latch synchronized to CPU control signals, isolating bus activity from downstream logic. Use Value: Prevents bus contention and enables deterministic data capture with 20 ns setup/5 ns hold timing margins at 5 V. | Use Scenario: One stage in a serial-in/parallel-out shift register for LED display multiplexing. IC Role / Device Role / Timing Role: Captures serial bit stream on each clock edge and presents parallel byte output for segment driver ICs. Use Value: Delivers clean, glitch-free parallel output with sub-30 ns propagation delay, minimizing display flicker in real-time refresh loops. |
| Pattern Generator | State Machine Register |
Use Scenario: Generating fixed test patterns (e.g., walking 1s, checkerboard) for digital circuit validation. IC Role / Device Role / Timing Role: Stores and repeats predefined 8-bit sequences under external clock and reset control. Use Value: Provides deterministic, repeatable stimulus with precise edge-aligned updates - critical for timing margin testing. | Use Scenario: Holding current state bits in a finite-state machine controlling motor sequencing or protocol handshaking. IC Role / Device Role / Timing Role: Serves as the state register, updated synchronously on each control clock edge with reset-on-error capability via CLR. Use Value: Ensures metastability-free state transitions and atomic reset across all bits - essential for robust control logic. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal D-type flip-flop applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS374N | Octal D-type transparent latch (3-state outputs), no CLR; requires external enable control | Lacks asynchronous clear; suited for bus-oriented applications needing output isolation | Select when bidirectional bus buffering or output disable is required instead of global reset |
| SN74HC273PW | CMOS version with 2–6 V supply range, lower ICC (<10 µA), higher fmax (≥50 MHz), but different VIH/VIL thresholds | Requires level translation when interfacing with legacy TTL systems; better for low-power or wide-VCC designs | Select for new designs targeting lower power or mixed-voltage operation, not drop-in replacement for SN74LS273DW |
Compared with SN74LS374N and SN74HC273PW, the SN74LS273DW uniquely combines guaranteed asynchronous clear, TTL-compatible thresholds, and proven 30 MHz performance in legacy 5 V systems - making it irreplaceable where deterministic reset and direct TTL interoperability are mandatory.
Availability
SN74LS273DW is available at Aetrix Electronics and suitable for industrial control panels, legacy instrumentation interfaces, and military-grade repair programs requiring stable component supply and long-term obsolescence management.
Supply support for SN74LS273DW 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 solutions with broad industrial, automotive, and aerospace reach.
The SN74LS273DW belongs to TI's legacy 74LS logic family, designed specifically for high-reliability, medium-speed digital register and storage functions in 5 V TTL systems - emphasizing compatibility, timing predictability, and field-proven robustness.
FAQ
What is the function of the CLR pin on the SN74LS273DW?
The CLR (clear) pin on the SN74LS273DW is an active-low asynchronous input that forces all eight Q outputs low immediately, independent of the clock signal. When asserted (logic low), it overrides all D inputs and clock edges, providing instantaneous register reset. This behavior is confirmed in the function table and logic diagram of TI's SDLS090 datasheet, and applies across the full commercial temperature range (0°C to 70°C).
Does the SN74LS273DW support 3.3 V operation?
No, the SN74LS273DW does not support 3.3 V operation. Its recommended supply voltage is strictly 4.75 V to 5.25 V, and absolute maximum VCC is 7 V. Operation below 4.75 V risks failure to meet timing specs (e.g., setup/hold times, propagation delay) and may cause output instability. For 3.3 V systems, consider CMOS alternatives like SN74HC273PW - but note they are not pin- or logic-compatible with SN74LS273DW.
What is the maximum clock frequency specification for SN74LS273DW?
The SN74LS273DW is guaranteed to operate up to 30 MHz across its recommended conditions (VCC = 4.75–5.25 V, TA = 0°C to 70°C). Typical maximum frequency is 40 MHz, as documented in the switching characteristics table of the SDLS090 datasheet. This rating assumes proper load conditions (CL = 15 pF, RL = 2 kΩ) and valid input timing margins (20 ns setup, 5 ns hold).
Is SN74LS273DW pin-compatible with SN74LS374N?
No, SN74LS273DW is not pin-compatible with SN74LS374N. While both are 20-pin SOIC octal D devices, their pinouts differ: SN74LS273DW places CLR on pin 1 and CLK on pin 19, whereas SN74LS374N uses pin 1 for OE (output enable) and pin 11 for CLK. Swapping them would cause functional failure and potential bus contention. Always verify pin mapping against respective datasheets before substitution.
What package type is used for SN74LS273DW?
The SN74LS273DW uses a 20-pin SOIC (Small Outline Integrated Circuit) package designated "DW" by Texas Instruments. It measures 7.5 mm wide, has 1.27 mm lead pitch, and 2.65 mm maximum height. This surface-mount package is RoHS-compliant, moisture-sensitive level 1 (unlimited reflow), and supplied in tape-and-reel format (2000 units per reel) for automated assembly.
SN74LS273DW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LS
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Master Reset
- Type:
- D-Type
- Output Type:
- Non-Inverted
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Clock Frequency:
- 40 MHz
- Max Propagation Delay @ V, Max CL:
- 27ns @ 5V, 15pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 400µA, 8mA
- Voltage - Supply:
- 4.75V ~ 5.25V
- Current - Quiescent (Iq):
- 27 mA
- Input Capacitance:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74LS273DW FAQ
1.How can I place an order for SN74LS273DW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LS273DW 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 SN74LS273DW reliable?
The price and inventory of SN74LS273DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS273DW is usually 5 days.
3.What payment methods are accepted for SN74LS273DW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS273DW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LS273DW?
SN74LS273DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LS273DW 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 SN74LS273DW?
For technical support, including SN74LS273DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS273DW requirements.
6.How does Aetrix verify that SN74LS273DW is sourced from the original manufacturer or authorized distributors?
All SN74LS273DW 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 SN74LS273DW meets industry standards.
7.What is the process for return or replacement of SN74LS273DW?
All SN74LS273DW units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS273DW, 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 SN74LS273DW part is unused and in its original packaging.
Return procedure for SN74LS273DW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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