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STMicroelectronics M74HCT74B1R
- Part No.:
- M74HCT74B1R
- Manufacturer:
- STMicroelectronics
- Category:
- Flip Flops
- Package:
- 14-DIP (0.300", 7.62mm)
- Datasheet:
-
M74HCT74B1R.pdf
- Description:
- IC FF D-TYPE DUAL 1BIT 14DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,598
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Product details
Overview
M74HCT74B1R from STMicroelectronics is a high-speed CMOS dual D-type flip-flop with asynchronous preset and clear, fabricated in silicon gate C2MOS technology. It operates at up to 48 MHz (typ.) at VCC = 4.5 V, delivers symmetrical output drive (|IOH| = IOL = 4 mA min), and features balanced propagation delays (tPLH ≅ tPHL). It directly interfaces HSC2MOS systems with TTL/NMOS logic in clocked data storage applications.
For engineers reviewing the M74HCT74B1R datasheet, M74HCT74B1R pinout, M74HCT74B1R application, or M74HCT74B1R equivalent, key selection criteria include its 14-pin DIP package, TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V), guaranteed operation from –55 °C to +125 °C, and low quiescent current (ICC ≤ 2 µA at TA = 25 °C).
Technical Context
The M74HCT74B1R implements two independent edge-triggered D flip-flops, each with asynchronous active-low preset (PR) and clear (CLR) inputs that override clock and data. Its positive-edge-triggered clock (CK) transfers the D-input state to Q on the rising transition, while Q̅ provides the complement.
Designed for mixed-logic interfacing, it meets TTL voltage compatibility (VIH min = 2.0 V, VIL max = 0.8 V) and drives ±4 mA outputs symmetrically. Input protection circuits guard against ESD and transient overvoltage, supporting robust operation in industrial control and instrumentation environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| fMAX | 48 MHz (typ.) at VCC = 4.5 V - supports high-speed synchronous logic in timing-critical control paths |
| tPLH / tPHL | 21–50 ns (max) - ensures predictable, balanced signal delay between clock and Q/Q̅ transitions |
| VIL / VIH | 0.8 V (max) / 2.0 V (min) - guarantees reliable recognition of TTL-level inputs without level-shifting |
| IOL / IOH | 4 mA (min) - enables direct fan-out to multiple standard TTL loads |
| ICC (quiescent) | 2 µA (max) at TA = 25 °C - minimizes standby power in battery-backed or energy-sensitive systems |
| Operating Temp | –55 °C to +125 °C - qualified for extended industrial and automotive under-hood applications |
| Supply Range | 4.5 V to 5.5 V - aligns with standard 5 V logic rails and tolerates supply ripple |
Pinout & Package
Package: Plastic Dual In-line Package (DIP-14), 0.3" wide, lead pitch 2.54 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 13 | 1CLR, 2CLR | Asynchronous active-low reset - forces Q = L, Q̅ = H independently of clock |
| 2, 12 | 1D, 2D | Data input - sampled on rising clock edge and latched to Q output |
| 3, 11 | 1CK, 2CK | Positive-edge-triggered clock - initiates data capture only on rising transition |
| 4, 10 | 1PR, 2PR | Asynchronous active-low preset - forces Q = H, Q̅ = L independently of clock |
| 5, 9 | 1Q, 2Q | True output - reflects latched D-state after clock edge or async control |
| 6, 8 | 1Q̅, 2Q̅ | Inverted output - complements Q; usable as feedback or differential signaling |
| 7 | GND | Ground reference - return path for all internal currents and logic thresholds |
| 14 | VCC | Positive supply - powers internal logic and output drivers at 4.5–5.5 V |
Key Features
| Feature | Design Value |
|---|---|
| TTL-compatible inputs | VIH ≥ 2.0 V and VIL ≤ 0.8 V enable direct connection to legacy TTL without interface circuitry |
| Symmetrical output drive | IOH = IOL = 4 mA (min) ensures matched rise/fall times and consistent loading across logic families |
| Asynchronous control | Dedicated PR/CLR pins per flip-flop allow immediate state initialization or reset regardless of clock phase |
| High noise immunity | Input protection diodes and 10 pF typical CIN suppress transients and reduce coupling-induced glitches |
| Wide temperature range | Specified from –55 °C to +125 °C supports deployment in harsh environmental conditions |
Applications
| Industrial PLC Timing Modules | Automotive Body Control Units |
|---|---|
Use Scenario: Synchronizing sensor sampling and actuator enable signals in cyclic scan-based controllers. IC Role / Device Role / Timing Role: Dual D flip-flop providing edge-aligned register stages for deterministic state sequencing. Use Value: Guaranteed tPLH/tPHL matching (≤5 ns skew) ensures precise inter-stage timing alignment across temperature. | Use Scenario: Debouncing mechanical switch inputs (e.g., door latch, ignition key) before feeding microcontroller GPIO. IC Role / Device Role / Timing Role: Asynchronous preset/clear enables immediate state capture on switch closure/opening, independent of system clock. Use Value: 0.8 V VIL max and 2.0 V VIH min ensure reliable detection of noisy, slow-rising automotive switch signals. |
| Test Equipment Pattern Generators | Legacy System Logic Upgrades |
Use Scenario: Generating multi-phase, non-overlapping clock enables for digital stimulus generation. IC Role / Device Role / Timing Role: Dual flip-flop configured as shift register stage to produce controlled delay and phase-shifted outputs. Use Value: 48 MHz fMAX and 6 ns minimum clock pulse width support high-frequency pattern rates up to 20 MHz. | Use Scenario: Replacing obsolete 74LS74 in aging instrumentation hardware requiring drop-in compatibility. IC Role / Device Role / Timing Role: Pin- and function-compatible upgrade delivering lower ICC and wider VCC tolerance than LS family. Use Value: 2 µA max ICC reduces board-level standby power by >95% versus 74LS74 (typically 8 mA), extending service life. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual D-type flip-flop applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT74N | Same logic function, identical AC/DC specs, but TI's DIP-14 packaging uses different mold compound and lead finish | No functional difference; validated for same industrial temp range (–40 to +85 °C), not rated to –55 °C | Select when full –55 °C qualification is not required and TI supply chain preference applies |
| 74HCT74D | NXP variant in SO-14 package; identical electrical specs but 150 °C max junction rating vs. ST's 150 °C (same) | SO-14 footprint requires PCB redesign; thermal resistance differs due to package geometry | Select for space-constrained designs where surface-mount assembly is mandatory |
Compared with SN74HCT74N and 74HCT74D, the M74HCT74B1R uniquely supports –55 °C operation and uses ST's proprietary C2MOS process for lower leakage, making it preferred for extended-temperature industrial and aerospace upgrades.
Availability
M74HCT74B1R is available at Aetrix Electronics and suitable for industrial PLC timing modules, automotive body control units, test equipment pattern generators, and legacy system logic upgrades requiring stable component supply across extended temperature ranges.
Supply support for M74HCT74B1R 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, digital, and mixed-signal ICs for industrial, automotive, and consumer markets.
The M74HCT74B1R belongs to ST's HCT logic family, engineered to bridge TTL and CMOS domains with robust noise immunity, low power, and extended temperature reliability for mission-critical control logic.
FAQ
Is M74HCT74B1R compatible with 74LS74 in existing PCB layouts?
Yes - M74HCT74B1R uses the same DIP-14 package (P001A) and pinout as 74LS74, with identical pin numbering and function mapping. Electrical compatibility is ensured by TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) and output drive capability (IOL/IOH ≥ 4 mA), allowing direct replacement without layout changes.
What is the maximum clock frequency supported across the full temperature range?
The M74HCT74B1R guarantees fMAX ≥ 22 MHz from –40 °C to +85 °C and ≥ 18 MHz from –55 °C to +125 °C, based on AC characterization with CL = 50 pF and input tr/tf ≤ 6 ns. At 25 °C and VCC = 4.5 V, typical operation reaches 48 MHz.
Does M74HCT74B1R require external pull-up or pull-down resistors on unused inputs?
No - all inputs feature internal protection diodes and have defined logic thresholds. However, floating inputs must be avoided: unused D, PR, or CLR pins should be tied to VCC or GND to prevent metastability or excessive ICC. The datasheet specifies II ≤ ±1 µA at VI = VCC/GND, confirming safe static biasing.
Can both flip-flops share the same clock signal while maintaining independent data and control?
Yes - the device contains two fully independent D flip-flops (1D/1CK/1PR/1CLR/1Q/1Q̅ and 2D/2CK/2PR/2CLR/2Q/2Q̅) sharing only VCC and GND. Each has dedicated control and data lines, enabling simultaneous but distinct operations - e.g., one stage synchronized to system clock, the other to an external event trigger.
M74HCT74B1R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- 74HCT
- Package/Case:
- 14-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Set(Preset) and Reset
- Type:
- D-Type
- Output Type:
- Complementary
- Number of Elements:
- 2
- Number of Bits per Element:
- 1
- Clock Frequency:
- 48 MHz
- Max Propagation Delay @ V, Max CL:
- 33ns @ 4.5V, 50pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 4mA, 4mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Current - Quiescent (Iq):
- 2 µA
- Input Capacitance:
- 5 pF
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 14-DIP
M74HCT74B1R FAQ
1.How can I place an order for M74HCT74B1R through Aetrix?
Please submit a Request for Quotation (RFQ) for M74HCT74B1R 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 M74HCT74B1R reliable?
The price and inventory of M74HCT74B1R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M74HCT74B1R is usually 5 days.
3.What payment methods are accepted for M74HCT74B1R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M74HCT74B1R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for M74HCT74B1R?
M74HCT74B1R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your M74HCT74B1R 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 M74HCT74B1R?
For technical support, including M74HCT74B1R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M74HCT74B1R requirements.
6.How does Aetrix verify that M74HCT74B1R is sourced from the original manufacturer or authorized distributors?
All M74HCT74B1R 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 M74HCT74B1R meets industry standards.
7.What is the process for return or replacement of M74HCT74B1R?
All M74HCT74B1R units undergo pre-shipment inspection (PSI). If there is an issue with M74HCT74B1R, 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 M74HCT74B1R part is unused and in its original packaging.
Return procedure for M74HCT74B1R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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