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Texas Instruments CD74HCT273M
- Part No.:
- CD74HCT273M
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
CD74HCT273M.pdf
- Description:
- IC FF D-TYPE SNGL 8BIT 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,433
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Product details
Overview
CD74HCT273M from Texas Instruments is an octal D-type flip-flop with asynchronous active-low reset, designed for synchronous data latching in 8-bit digital systems. It operates at 4.5V–5.5V, features positive-edge clock triggering, 25 MHz max clock frequency (at 5V, CL = 15 pF), and delivers CMOS-level outputs compatible with LSTTL inputs. It is used in bus interface synchronization and simple 8-bit register storage.
For engineers reviewing the CD74HCT273M datasheet, CD74HCT273M pinout, CD74HCT273M application, or CD74HCT273M equivalent, key selection factors include its HCT-family TTL-compatible input thresholds (VIL ≤ 0.8 V, VIH ≥ 2.0 V), guaranteed operation from –55°C to +125°C, and SOIC-20 package with verified 20-pin terminal mapping.
Technical Context
The CD74HCT273M implements eight independent D-type latches sharing a common clock (CLK) and a single asynchronous clear (CLR) input. Each flip-flop transfers data from Dn to Qn on the rising edge of CLK, while CLR forces all Q outputs low regardless of clock state. Its HCT logic family ensures direct compatibility with legacy TTL signal levels without level-shifting.
It uses silicon-gate CMOS technology with buffered inputs and balanced push-pull outputs capable of sourcing/sinking ±25 mA per pin. Propagation delay is 30 ns typical (CL = 50 pF, VCC = 4.5 V), and input capacitance is 10 pF - enabling stable high-speed operation in noise-sensitive industrial control and instrumentation timing paths.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | HCT - TTL-compatible CMOS inputs (VIH ≥ 2.0 V, VIL ≤ 0.8 V at VCC = 4.5–5.5 V) |
| Supply Voltage Range | 4.5 V to 5.5 V - matches standard 5 V TTL/CMOS system rails |
| Max Clock Frequency | 25 MHz (20 MHz over –40°C to +85°C) - supports medium-speed digital control loops |
| Propagation Delay (tPLH/tPHL) | 30 ns typical (CL = 50 pF, VCC = 4.5 V) - enables precise timing alignment in synchronous buses |
| Operating Temperature | –55°C to +125°C - qualified for extended industrial and aerospace environments |
| Input Capacitance (CIN) | 10 pF - minimizes loading on driving gates and preserves signal integrity |
| Output Drive | ±25 mA per output - sufficient to drive 4 LSTTL loads or light capacitive loads ≤50 pF |
Pinout & Package
DW package: 20-pin SOIC, 12.80 mm × 7.50 mm body, gull-wing leads, JEDEC MS-013 compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (CLR) | Asynchronous reset input | Active-low global clear - forces all Q outputs to logic 0 independently of CLK |
| 11 (CLK) | Clock input | Positive-edge-triggered - samples all D inputs simultaneously on rising transition |
| 3,4,7,8,13,14,17,18 (D1–D8) | Data inputs | Independent 8-bit parallel data path - each maps directly to corresponding Q output |
| 2,5,6,9,12,15,16,19 (Q1–Q8) | Registered outputs | Edge-aligned, non-inverting outputs - retain state until next CLK edge or CLR assertion |
| 10 (GND) | Ground reference | Common return for logic and output current - must be low-impedance for noise immunity |
| 20 (VCC) | Power supply | +4.5 V to +5.5 V supply - requires local 0.1 µF bypass capacitor per device |
Key Features
| Feature | Design Value |
|---|---|
| Asynchronous active-low reset | Enables immediate, clock-independent register clearing - critical for system initialization and fault recovery |
| TTL-compatible input thresholds | Accepts standard LSTTL outputs directly (VIH ≥ 2.0 V, VIL ≤ 0.8 V) - eliminates need for external level shifters |
| Wide temperature range | –55°C to +125°C operation - supports deployment in under-hood automotive, downhole, and military systems |
| Low quiescent current | ICC ≤ 160 µA at 5.5 V and –55°C to +125°C - reduces standby power in battery-backed or thermally constrained designs |
| CMOS push-pull outputs | Balanced sourcing/sinking (±25 mA) - ensures clean logic transitions into mixed-technology loads |
Applications
| Industrial Bus Synchronization | Microcontroller I/O Expansion |
|---|---|
Use Scenario: Aligning asynchronous sensor data streams (e.g., ADC outputs, encoder pulses) to a central system clock in PLC backplanes. IC Role / Device Role / Timing Role: Edge-triggered register capturing 8-bit parallel data on rising CLK edge; CLR resets latch state before new acquisition cycle. Use Value: Eliminates metastability risk and ensures deterministic sampling windows - improves real-time determinism in closed-loop control. | Use Scenario: Extending GPIO count of an MCU by latching parallel commands from SPI/I²C-to-parallel bridge ICs. IC Role / Device Role / Timing Role: Holding command bits (e.g., motor enable, LED pattern select) until next instruction cycle; CLR provides hardware reset override. Use Value: Offloads timing-critical bit-banging from firmware; enables glitch-free peripheral activation synchronized to system clock. |
| Legacy System Interface | Test Equipment Data Capture |
Use Scenario: Interfacing modern microcontrollers with older TTL-based logic boards (e.g., vintage test gear, industrial controllers). IC Role / Device Role / Timing Role: Level-translating and synchronizing 8-bit status/control words between 3.3 V MCU and 5 V TTL subsystems. Use Value: Maintains full DC and AC compatibility - no external resistors or buffers needed for voltage translation. | Use Scenario: Capturing parallel digital waveform snapshots from FPGA-based logic analyzers or ATE fixtures. IC Role / Device Role / Timing Role: Storing one sample of 8-bit bus activity on trigger event; CLR clears buffer before next capture. Use Value: Provides deterministic, jitter-free sampling window - essential for accurate timing margin analysis and protocol validation. |
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 |
|---|---|---|---|
| SN74HCT273N | Same HCT logic, identical timing and DC specs, but in PDIP-20 package (25.4 mm × 6.35 mm) | Preferred for through-hole prototyping or legacy board rework where SOIC footprint is unavailable | Select when manual soldering, breadboarding, or mechanical mounting constraints favor DIP over SOIC |
| 74HCT273PW | TSSOP-20 package (6.5 mm × 4.4 mm); same electrical behavior but smaller footprint and higher thermal resistance (RθJA = 101°C/W) | Suitable for space-constrained PCBs where density outweighs thermal budget limitations | Choose for compact consumer or portable electronics where board area is premium and ambient temperature remains <85°C |
Compared with SN74HCT273N and 74HCT273PW, the CD74HCT273M offers the best balance of thermal performance (RθJA = 58°C/W), industrial temperature rating, and surface-mount reliability in standard SOIC-20 - making it optimal for production-grade embedded systems requiring long-term stability.
Availability
CD74HCT273M is available at Aetrix Electronics and suitable for industrial automation, test equipment, and aerospace avionics requiring stable component supply across extended temperature ranges and multi-year production cycles.
Supply support for CD74HCT273M 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 specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
The CD74HCT273M belongs to TI's high-speed CMOS logic portfolio, engineered specifically for robust, drop-in replacement of legacy TTL registers in noise-immune, wide-temperature digital systems.
FAQ
What is the maximum clock frequency supported by the CD74HCT273M?
The CD74HCT273M supports a maximum clock frequency of 25 MHz at VCC = 4.5 V and TA = 25°C (CL = 15 pF). Over the full industrial temperature range (–40°C to +85°C), the guaranteed maximum is 20 MHz. At extended temperature (–55°C to +125°C), the limit drops to 16 MHz. These values are measured under specified load and rise/fall time conditions per TI's SCHS174D datasheet.
Does the CD74HCT273M require external pull-up or pull-down resistors on unused inputs?
Yes - all unused inputs on the CD74HCT273M must be terminated to either VCC or GND. Floating CMOS inputs cause excessive power consumption, oscillation, and potential device damage. A 10 kΩ resistor is recommended for pull-up/pull-down; direct connection is acceptable if the input is permanently inactive. This applies to all D inputs, CLK, and CLR when not in use.
Can the CD74HCT273M drive LSTTL loads directly?
Yes - the CD74HCT273M is explicitly designed for direct LSTTL compatibility. Its input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) match LSTTL output levels, and its outputs deliver VOH ≥ 3.7 V and VOL ≤ 0.4 V at IOL = 4 mA - meeting LSTTL fanout requirements. No level-shifting circuitry is needed when interfacing with 74LS-series devices.
What is the purpose of the CLR pin on the CD74HCT273M, and how does it behave?
The CLR (pin 1) is an asynchronous, active-low reset input that forces all eight Q outputs to logic 0 immediately - independent of the clock signal. When CLR is pulled low, Qn = 0 regardless of CLK state or Dn value. When CLR returns high, the next rising CLK edge captures new D-input data. This enables hardware-initiated register clearing without waiting for clock edges.
Is the CD74HCT273M suitable for operation at –55°C?
Yes - the CD74HCT273M is fully specified and tested for operation from –55°C to +125°C. Its electrical characteristics (propagation delay, setup/hold times, output drive) are guaranteed across this full range per the manufacturer's Recommended Operating Conditions table. This makes it suitable for aerospace, defense, and extreme-environment industrial applications where extended temperature qualification is mandatory.
CD74HCT273M Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- 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:
- 50 MHz
- Max Propagation Delay @ V, Max CL:
- 30ns @ 4.5V, 50pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 4mA, 4mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Current - Quiescent (Iq):
- 8 µA
- Input Capacitance:
- 10 pF
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
CD74HCT273M FAQ
1.How can I place an order for CD74HCT273M through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74HCT273M 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 CD74HCT273M reliable?
The price and inventory of CD74HCT273M are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74HCT273M is usually 5 days.
3.What payment methods are accepted for CD74HCT273M?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74HCT273M transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74HCT273M?
CD74HCT273M orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74HCT273M 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 CD74HCT273M?
For technical support, including CD74HCT273M datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74HCT273M requirements.
6.How does Aetrix verify that CD74HCT273M is sourced from the original manufacturer or authorized distributors?
All CD74HCT273M 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 CD74HCT273M meets industry standards.
7.What is the process for return or replacement of CD74HCT273M?
All CD74HCT273M units undergo pre-shipment inspection (PSI). If there is an issue with CD74HCT273M, 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 CD74HCT273M part is unused and in its original packaging.
Return procedure for CD74HCT273M:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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