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STMicroelectronics M74HC74B1R
- Part No.:
- M74HC74B1R
- Manufacturer:
- STMicroelectronics
- Category:
- Flip Flops
- Package:
- 14-DIP (0.300", 7.62mm)
- Datasheet:
-
M74HC74B1R.pdf
- Description:
- IC FF D-TYPE DUAL 1BIT 14DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,191
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Product details
Overview
M74HC74B1R from STMicroelectronics is a high-speed CMOS dual D-type flip-flop with independent asynchronous preset and clear, operating across 2V–6V supply, delivering tPLH/tPHL ≈ 13 ns (typ. at VCC = 6V), fMAX = 67 MHz (typ.), and symmetrical 4 mA output drive. It serves as edge-triggered storage logic in synchronous digital systems such as clock domain synchronization and state machine registers.
For engineers reviewing the M74HC74B1R datasheet, M74HC74B1R pinout, M74HC74B1R application, or M74HC74B1R equivalent, key selection criteria include propagation delay matching, asynchronous control timing margins, supply voltage flexibility, and DIP-14 mechanical compatibility for legacy board layouts.
Technical Context
The device implements two independent positive-edge-triggered D flip-flops, each with active-low asynchronous set (PR) and reset (CLR) inputs that override clock and data. Its C2MOS silicon gate process enables low ICC = 2 µA (max) at 25°C while maintaining noise immunity of ≥28% VCC.
All inputs feature ESD protection; outputs exhibit balanced |IOH| = IOL = 4 mA (min) drive capability and matched tPLH ≅ tPHL propagation delays. Input rise/fall time limits are specified per VCC (e.g., ≤400 ns at 6V), ensuring reliable edge detection under real-world signal integrity conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2 V to 6 V - supports mixed-voltage system interfacing and battery-powered operation down to 2 V. |
| fMAX | 67 MHz (typ. at VCC = 6 V) - enables use in high-speed control sequencers and data latching up to ~15 ns clock period. |
| tPLH / tPHL | 13 ns (typ. at VCC = 6 V, CL = 50 pF) - ensures tight setup/hold timing budgets in synchronous pipelines. |
| IOH / IOL | –4 mA / +4 mA (min) - drives standard TTL loads and multiple 74HC inputs without buffering. |
| VNIH / VNIL | ≥28% VCC (min) - provides robust noise margin against ground bounce and crosstalk in dense PCB layouts. |
| ICC (Quiescent) | 2 µA (max at TA = 25°C) - minimizes standby power in always-on logic monitoring circuits. |
| ts / th | 3 ns setup / 0 ns hold (at VCC = 6 V) - simplifies timing closure with minimal data-to-clock skew constraints. |
Pinout & Package
Package: Plastic Dual In-line Package (DIP-14), 20.0 mm × 8.5 mm body, 2.54 mm lead pitch, through-hole mounting.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 13 | 1CLR, 2CLR | Active-low asynchronous reset - forces Q = L, Q̄ = H independent of clock; requires pull-up for static high. |
| 2, 12 | 1D, 2D | Data input - sampled on rising clock edge; latched value appears at Q after tPLH/tPHL. |
| 3, 11 | 1CK, 2CK | Positive-edge-triggered clock - transition from L to H initiates sampling; minimum pulse width = 6 ns (at 6 V). |
| 4, 10 | 1PR, 2PR | Active-low asynchronous preset - forces Q = H, Q̄ = L independent of clock; overrides D and CK. |
| 5, 9 | 1Q, 2Q | True output - complements Q̄; fan-out limited by IOH/IOL and capacitive load. |
| 6, 8 | 1Q̄, 2Q̄ | Inverted output - complements Q; electrically identical to Q in drive strength and timing. |
| 7 | GND | Ground reference - must be low-impedance connection to minimize switching noise coupling. |
| 14 | VCC | Positive supply - bypassing with 100 nF ceramic capacitor near pin is mandatory for stable AC operation. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent flip-flops | Two fully isolated storage cells share only VCC/GND - enables compact dual-channel register design without inter-cell timing dependency. |
| Asynchronous preset/clear | PR and CLR assert within tPLH ≈ 13 ns (6 V) - allows immediate state initialization prior to clock enable in boot-up or fault recovery sequences. |
| Supply voltage range | 2 V–6 V operation - interoperable with 3.3 V microcontrollers and 5 V legacy peripherals without level shifters. |
| High noise immunity | VNIH/VNIL ≥ 28% VCC - tolerates ≥1.68 V noise on 6 V rails, reducing false triggering in industrial EMI environments. |
| Low quiescent current | ICC ≤ 2 µA at 25°C - extends battery life in portable logic monitors and sensor interface wake-up controllers. |
Applications
| Industrial PLC I/O Modules | Digital Power Supply Sequencing |
|---|---|
Use Scenario: Capturing status signals from isolated field sensors before CPU readout in cyclic scan mode. IC Role / Device Role / Timing Role: Edge-triggered data latch synchronizing asynchronous sensor interrupts to the PLC's deterministic scan clock. Use Value: Eliminates metastability risk via controlled setup/hold timing and provides fail-safe reset during power-up sequencing. | Use Scenario: Enabling DC-DC converter rails in strict order (e.g., bias first, then core, then I/O) using discrete logic. IC Role / Device Role / Timing Role: Asynchronous state controller holding enable signals until upstream rail reaches regulation threshold. Use Value: Independent PR/CLR allows hard-wired power-good assertion without clock dependency, improving startup reliability. |
| Legacy Test Equipment Control Logic | Automotive Body Control Unit Registers |
Use Scenario: Storing test pattern bits in automated functional testers where DIP-14 sockets simplify field-replaceable logic modules. IC Role / Device Role / Timing Role: Static register bank holding stimulus vectors synchronized to tester master clock. Use Value: DIP-14 package enables socket-based reconfiguration; 67 MHz fMAX supports >10 MHz pattern rates. | Use Scenario: Latching door lock/unlock commands from LIN bus transceivers in low-power sleep/wake cycles. IC Role / Device Role / Timing Role: Low-ICC storage element retaining command state across microcontroller deep-sleep modes. Use Value: 2 µA max quiescent current prevents battery drain; 2 V min VCC supports operation during cranking voltage dips. |
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 |
|---|---|---|---|
| SN74HC74N | Same pinout, identical AC/DC specs, TI-branded DIP-14 variant; tPLH/tPHL = 15 ns (typ. at 6 V). | Qualified to AEC-Q100 Grade 3; preferred for automotive production where TI sourcing is mandated. | Select when requiring TI-specific qualification documentation or dual-source procurement strategy. |
| 74HC74D | SO-14 surface-mount package; same logic function but no DIP-14 mechanical compatibility. | Designed for space-constrained PCBs; lacks through-hole serviceability and socket-based prototyping support. | Select when board area is constrained and rework via hot-air station is acceptable. |
Compared with SN74HC74N and 74HC74D, M74HC74B1R uniquely combines DIP-14 through-hole mountability, STMicroelectronics' extended –55°C to +125°C operating range, and documented 2 µA max ICC - making it optimal for industrial field equipment requiring serviceability and wide-temperature reliability.
Availability
M74HC74B1R is available at Aetrix Electronics and suitable for industrial PLC I/O modules, digital power supply sequencing, and legacy test equipment requiring stable component supply with long-lifecycle DIP-14 packaging.
Supply support for M74HC74B1R 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, specializing in automotive, industrial, and power management ICs with vertical manufacturing and broad analog/digital portfolio.
M74HC74B1R belongs to the M74HC high-speed CMOS logic family, designed for pin-compatible replacement of legacy 74LS devices while delivering lower power, wider voltage range, and improved noise immunity in industrial control and instrumentation.
FAQ
What is the maximum clock frequency supported by M74HC74B1R?
The M74HC74B1R supports a maximum clock frequency of 67 MHz (typical) at VCC = 6 V and CL = 50 pF, with guaranteed minimum fMAX = 30 MHz across the full –55°C to +125°C operating range. This rating assumes clean 6 ns input rise/fall times and proper power supply decoupling.
Can M74HC74B1R operate reliably at 3.3 V?
Yes - M74HC74B1R is fully specified from 2 V to 6 V, including 3.3 V operation. At VCC = 3.3 V, it delivers tPLH/tPHL ≤ 38 ns (max), fMAX ≥ 25 MHz, and VIH ≥ 2.31 V, making it interoperable with 3.3 V microcontrollers and FPGAs without level translation.
Does M74HC74B1R require external pull-up resistors on PR and CLR pins?
Yes - PR and CLR are active-low inputs with no internal pull-ups. To prevent unintended reset or preset during power-up or floating states, external 10 kΩ pull-up resistors to VCC are required unless actively driven low by system logic.
Is M74HC74B1R RoHS compliant and halogen-free?
Yes - M74HC74B1R (DIP-14 package) conforms to RoHS Directive 2011/65/EU and is manufactured as a halogen-free device per IEC 61249-2-21, with lead finish composed of matte tin over nickel underplate and no intentionally added antimony or phosphorus flame retardants.
M74HC74B1R Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- 74HC
- 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:
- 67 MHz
- Max Propagation Delay @ V, Max CL:
- 26ns @ 6V, 50pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 5.2mA, 5.2mA
- Voltage - Supply:
- 2V ~ 6V
- 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
M74HC74B1R FAQ
1.How can I place an order for M74HC74B1R through Aetrix?
Please submit a Request for Quotation (RFQ) for M74HC74B1R 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 M74HC74B1R reliable?
The price and inventory of M74HC74B1R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M74HC74B1R is usually 5 days.
3.What payment methods are accepted for M74HC74B1R?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M74HC74B1R transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for M74HC74B1R?
M74HC74B1R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your M74HC74B1R 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 M74HC74B1R?
For technical support, including M74HC74B1R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M74HC74B1R requirements.
6.How does Aetrix verify that M74HC74B1R is sourced from the original manufacturer or authorized distributors?
All M74HC74B1R 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 M74HC74B1R meets industry standards.
7.What is the process for return or replacement of M74HC74B1R?
All M74HC74B1R units undergo pre-shipment inspection (PSI). If there is an issue with M74HC74B1R, 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 M74HC74B1R part is unused and in its original packaging.
Return procedure for M74HC74B1R:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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