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NXP Semiconductors 74HC123N,652
- Part No.:
- 74HC123N,652
- Manufacturer:
- NXP Semiconductors
- Category:
- Multivibrators
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
74HC123N,652.pdf
- Description:
- IC MULTIVIBRATOR 65NS 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,463
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Product details
Overview
74HC123N,652 from NXP Semiconductors is a dual retriggerable monostable multivibrator in a 16-pin DIP package, operating from 2.0 V to 6.0 V with −40 °C to +125 °C temperature range. It provides two independent timing channels, each with three pulse-width control methods (external REXT/CEXT, retriggering via nA/nB edges, and direct reset via nRD), and features Schmitt-trigger inputs on nA/nB for noise immunity. It is used in digital timing, debounce, pulse stretching, and delay generation circuits.
For engineers reviewing the 74HC123N,652 datasheet, 74HC123N,652 pinout, 74HC123N,652 application, or 74HC123N,652 equivalent, this page delivers verified functional architecture, exact pin roles, real-world timing behavior under varying REXT/CEXT, reset response latency, and validated alternatives for industrial control and legacy TTL-compatible designs.
Technical Context
The 74HC123N,652 implements two independent CMOS monostable circuits, each with gated active-LOW (nA) and active-HIGH (nB) trigger inputs plus a shared direct-reset input (nRD) that also functions as a positive-edge trigger. Its output pulse width is programmable via external REXT and CEXT components, with typical tW = 0.45 × REXT(kΩ) × CEXT(pF) at VCC = 5.0 V.
Retriggering extends the output pulse indefinitely - each new valid edge on nA or nB restarts the timing cycle - while a LOW-going edge on nRD terminates the pulse immediately. Schmitt-trigger action on nA and nB ensures robust operation with slow-rising/falling signals, and the device complies with JEDEC standard no. 7A for LSTTL pin compatibility.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply voltage | 2.0 V to 6.0 V - supports mixed-voltage system interfacing and battery-powered operation down to 2 V. |
| Operating temperature | −40 °C to +125 °C - qualified for automotive under-hood and industrial motor-control environments. |
| Propagation delay | 24 ns (typ) at VCC = 6.0 V - enables precise sub-50 ns timing control in high-speed logic systems. |
| Pulse width range | 75 ns to >450 µs - set by REXT (2–1000 kΩ) and CEXT (up to 100 nF); supports both nanosecond delays and long-duration pulses. |
| Input hysteresis | Schmitt-trigger on nA/nB only - rejects noise on slow edges; nRD has no hysteresis and responds directly to transitions. |
| Output drive | ±25 mA - sufficient to directly drive LEDs, small relays, or interface with 74-series TTL/CMOS loads without buffering. |
| ESD protection | HBM >2000 V, MM >200 V - meets industrial handling requirements without additional protection circuitry. |
Pinout & Package
74HC123N,652 uses the SOT38-4 plastic dual in-line package (DIP16), 300-mil width, through-hole mountable with 2.54 mm pitch. Pin 1 is top-left corner when notch faces up.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1A | Negative-edge triggered input (Channel 1) | Triggers monostable on HIGH-to-LOW transition; Schmitt-triggered for noise immunity. |
| 1B | Positive-edge triggered input (Channel 1) | Triggers monostable on LOW-to-HIGH transition; Schmitt-triggered. |
| 1RD | Direct reset / positive-edge trigger (Channel 1) | Active-LOW reset terminates output pulse; also accepts rising-edge trigger per Table 3. |
| 1Q | Active-LOW output (Channel 1) | Drives LOW during monostable pulse; complements 1Q (pin 13). |
| 2Q | Active-HIGH output (Channel 2) | Drives HIGH during monostable pulse; complements 2Q (pin 12). |
| 2CEXT | External capacitor connection (Channel 2) | Connects timing capacitor CEXT2 to ground; must be externally grounded per Fig 13 for noise reduction. |
| 2REXT/CEXT | Shared resistor/capacitor node (Channel 2) | Common terminal for REXT2 and CEXT2; internal connection defines RC time constant. |
| GND | Ground reference (0 V) | Reference for all inputs, outputs, and timing components; pin 8 is primary ground return path. |
| 2A, 2B, 2RD | Channel 2 trigger/reset inputs | Functionally identical to pins 1A/1B/1RD but for second independent monostable. |
| 1CEXT, 1REXT/CEXT | Channel 1 timing component nodes | Identical role to pins 6 and 7, but for first channel; pin 14 (1CEXT) must be grounded externally. |
| VCC | Positive supply | Accepts 2.0–6.0 V; decoupling capacitor recommended near pin 16 to suppress switching noise. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent monostables | Enables two separate timing functions (e.g., input debounce + output delay) in one IC, reducing board space and BOM count. |
| Three pulse-width control methods | Supports fixed timing (REXT/CEXT), dynamic extension (retriggering), and immediate termination (nRD), enabling adaptive pulse generation. |
| Retriggerable up to 100 % duty factor | Allows indefinite pulse extension - critical for watchdog timeout supervision or variable-length signal gating without external logic. |
| Schmitt-trigger inputs on nA/nB | Eliminates need for external RC filters on slow or noisy control lines (e.g., mechanical switch inputs or long PCB traces). |
| Direct reset with dual function | nRD serves both as hard reset (LOW) and alternate trigger (rising edge), simplifying control logic in state machines or fault recovery circuits. |
Applications
| Industrial Pushbutton Debounce | Serial Data Pulse Stretching |
|---|---|
|
Use Scenario: Mechanical pushbuttons in PLC I/O modules generate contact bounce lasting 1–10 ms. IC Role / Device Role / Timing Role: 74HC123N,652 Channel 1 acts as a hardware debouncer, generating a clean, fixed-duration output pulse after first valid edge. Use Value: Eliminates microcontroller polling or software debounce; pulse width set by REXT=10 kΩ and CEXT=100 nF yields ~450 µs stable output. |
Use Scenario: UART RX line receives short start bits (<1 µs) that may be missed by slow interrupt handlers. IC Role / Device Role / Timing Role: 74HC123N,652 Channel 2 stretches narrow incoming pulses to ≥10 µs using REXT=100 kΩ and CEXT=100 pF. Use Value: Ensures reliable edge detection by MCU GPIOs with 10 µs minimum pulse width requirement; retriggering prevents false resets during multi-bit frames. |
| Motor Control Fault Timeout | Legacy TTL System Timing Upgrade |
|
Use Scenario: Overcurrent detection in BLDC inverters requires fast shutdown if fault persists >100 µs. IC Role / Device Role / Timing Role: 74HC123N,652 Channel 1 monitors fault signal; nRD tied to enable line, allowing immediate reset on safe state return. Use Value: Provides deterministic 100 µs timeout (REXT=20 kΩ, CEXT=100 pF) with hardware-level reset - no firmware dependency or latency. |
Use Scenario: Upgrading 74LS123-based test equipment where PCB layout cannot change. IC Role / Device Role / Timing Role: 74HC123N,652 replaces 74LS123 in pin-compatible DIP16 footprint, delivering same timing behavior with lower power and wider voltage range. Use Value: Maintains full backward compatibility while reducing supply current from ~25 mA to <160 µA (ICC max at 125 °C), extending system thermal margin. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar monostable multivibrator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74HCT123N,652 | CMOS input thresholds compatible with TTL logic levels (VIH = 2.0 V min); identical pinout and timing behavior. | Better suited for mixed 5 V TTL/CMOS systems where input drive originates from LS-TTL outputs. | Select when interfacing with legacy 74LS/74ALS logic families; otherwise 74HC123N,652 offers wider VCC range and lower ICC. |
| SN74LV123AN | Texas Instruments LV-family part; operates from 2.0 V to 5.5 V, with faster tpd (19 ns typ at 5 V) and lower ICC (10 µA typ). | Limited to +85 °C max ambient; not qualified for +125 °C industrial use. | Prefer for cost-sensitive consumer or telecom applications below 85 °C; avoid where extended temperature range is required. |
Compared with 74HCT123N,652 and SN74LV123AN, the 74HC123N,652 uniquely supports full −40 °C to +125 °C operation with 2.0–6.0 V supply flexibility, making it the only choice for high-reliability industrial and automotive timing where temperature and voltage margins are critical.
Availability
74HC123N,652 is available at Aetrix Electronics and suitable for industrial automation, motor control, and legacy system upgrades requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for 74HC123N,652 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
NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with deep expertise in logic, interface, and timing ICs.
The 74HC123N,652 belongs to NXP's legacy HC logic family, designed specifically for drop-in replacement of bipolar TTL monostables while delivering CMOS power efficiency, noise immunity, and extended voltage/temperature operation.
FAQ
What is the maximum operating temperature for the 74HC123N,652?
The 74HC123N,652 is rated for operation from −40 °C to +125 °C, as confirmed in Table 1 (Ordering Information) and Table 5 (Recommended Operating Conditions). This full industrial temperature range makes it suitable for under-hood automotive and high-temperature industrial control applications where standard 74HC devices (−40 °C to +85 °C) would fail.
Can the 74HC123N,652 be used with a 3.3 V supply?
Yes, the 74HC123N,652 supports VCC from 2.0 V to 6.0 V per Table 5, including 3.3 V operation. At 3.3 V, VIH is 2.31 V (70 % of VCC) and VIL is 0.99 V (30 % of VCC), ensuring compatibility with 3.3 V CMOS logic families. Propagation delay increases slightly versus 5 V operation but remains within specification.
How does retriggering work on the 74HC123N,652?
Retriggering on the 74HC123N,652 occurs when a valid edge arrives on nA (LOW-going) or nB (HIGH-going) during an active output pulse - each such edge restarts the timing cycle from zero. This allows indefinite pulse extension, enabling applications like watchdog timeouts or variable-length signal gating without external counters or microcontrollers.
Is the reset input (nRD) of the 74HC123N,652 Schmitt-triggered?
No, the nRD input of the 74HC123N,652 is not Schmitt-triggered - only nA and nB inputs have Schmitt-trigger action, as explicitly stated in the General Description section. nRD responds directly to logic-level transitions, so clean, fast-rising/falling reset signals are required to avoid metastability or unintended triggering.
What external components are required for basic operation of the 74HC123N,652?
Each channel of the 74HC123N,652 requires one external resistor (REXT) and one external capacitor (CEXT) to set the base pulse width. Per Figure 13 and Section 12.1, pins 14/15 (Channel 1) and 6/7 (Channel 2) connect to these components, and pins 14 (1CEXT) and 6 (2CEXT) must be externally grounded to minimize noise coupling into the timing network.
74HC123N,652 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- 74HC
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Monostable
- Independent Circuits:
- 2
- Schmitt Trigger Input:
- No
- Propagation Delay:
- 65 ns
- Current - Output High, Low:
- 5.2mA, 5.2mA
- Voltage - Supply:
- 2 V ~ 6 V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 16-DIP
74HC123N,652 FAQ
1.How can I place an order for 74HC123N,652 through Aetrix?
Please submit a Request for Quotation (RFQ) for 74HC123N,652 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 74HC123N,652 reliable?
The price and inventory of 74HC123N,652 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74HC123N,652 is usually 5 days.
3.What payment methods are accepted for 74HC123N,652?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74HC123N,652 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74HC123N,652?
74HC123N,652 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74HC123N,652 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 74HC123N,652?
For technical support, including 74HC123N,652 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74HC123N,652 requirements.
6.How does Aetrix verify that 74HC123N,652 is sourced from the original manufacturer or authorized distributors?
All 74HC123N,652 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 74HC123N,652 meets industry standards.
7.What is the process for return or replacement of 74HC123N,652?
All 74HC123N,652 units undergo pre-shipment inspection (PSI). If there is an issue with 74HC123N,652, 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 74HC123N,652 part is unused and in its original packaging.
Return procedure for 74HC123N,652:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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