My Inquiry
My Account
Nexperia USA Inc. 74HCT4538D,112
- Part No.:
- 74HCT4538D,112
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Multivibrators
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
74HCT4538D,112.pdf
- Description:
- IC MULTIVIBRATOR 35NS 16SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,718
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
74HCT4538D,112 from Nexperia is a dual retriggerable-resettable precision monostable multivibrator in SO16 package, operating from 4.5 V to 5.5 V across –40 °C to +125 °C. Each channel provides independent edge-triggered timing (rising or falling), active-low direct reset (nCD), complementary outputs (nQ/nQ), and external REXT/CEXT-based pulse width control (TW = 0.7 × REXT × CEXT). It delivers ±0.2 % pulse width variation over temperature and supports industrial timing applications requiring retriggerable one-shot behavior with Schmitt-trigger input tolerance.
For engineers reviewing the 74HCT4538D,112 datasheet, 74HCT4538D,112 pinout, 74HCT4538D,112 application, or 74HCT4538D,112 equivalent, key selection considerations include dual-channel retriggerability, external timing component dependency, TTL-compatible inputs, ±0.2 % pulse stability, and SO16 packaging for legacy PCB compatibility.
Technical Context
The device implements two independent monostable circuits, each with dual trigger inputs (nA for falling-edge, nB for rising-edge), a dedicated active-low reset (nCD), and complementary outputs. Timing is fully determined by external REXT and CEXT components connected to pins nREXT/CEXT and nCEXT, enabling programmable pulse widths from sub-microsecond to millisecond ranges.
Schmitt-trigger inputs provide noise immunity and tolerate slow signal edges; clamp diodes allow interfacing to voltages exceeding VCC using current-limiting resistors. The circuit features linear design techniques for precise pulse width control and immediate output termination on nCD assertion.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply voltage | 4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL/CMOS logic rails |
| Operating temperature | –40 °C to +125 °C - qualified for extended industrial environments |
| Pulse width accuracy | ±0.2 % over temperature - enables high-precision timing without calibration |
| Propagation delay | 30 ns to 90 ns (VCC = 4.5 V) - supports fast response in real-time control loops |
| Input threshold | VIL ≤ 0.8 V, VIH ≥ 2.0 V - guarantees robust TTL-level signal recognition |
| Output drive | ±4 mA at VOH/VOL - sufficient to directly drive CMOS loads or small LEDs |
| Timing equation | TW = 0.7 × REXT × CEXT - defines deterministic, externally adjustable pulse duration |
Pinout & Package
74HCT4538D,112 is housed in a plastic small outline package (SO16, SOT109-1) with 16 leads and 3.9 mm body width, suitable for surface-mount assembly and legacy through-hole footprint adaptation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 15 (1CEXT, 2CEXT) | External capacitor connection | Ground-referenced node for timing capacitor CEXT per channel |
| 2, 14 (1REXT/CEXT, 2REXT/CEXT) | External resistor/capacitor junction | Connects REXT and CEXT to set pulse width via TW = 0.7 × REXT × CEXT |
| 3, 13 (1CD, 2CD) | Direct reset input | Active-LOW asynchronous termination of output pulse |
| 4, 12 (1B, 2B) | Rising-edge trigger input | Triggers monostable on LOW-to-HIGH transition |
| 5, 11 (1A, 2A) | Falling-edge trigger input | Triggers monostable on HIGH-to-LOW transition |
| 6, 10 (1Q, 2Q) | True output | Active-HIGH output pulse synchronized to trigger event |
| 7, 9 (1Q, 2Q) | Complementary output | Active-LOW inverted pulse matching true output timing |
| 8 | GND | Reference ground for all internal circuitry and external timing components |
| 16 | VCC | Primary power supply rail (4.5 V to 5.5 V) |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent monostables | Enables two separate, non-interacting timing functions on one IC - reduces board space and BOM count |
| Retriggerable & resettable operation | Allows pulse extension during active timing or forced early termination via nCD - critical for fault-safe systems |
| Schmitt-trigger inputs | Accepts slow-rising/falling signals without false triggering - eliminates need for external signal conditioning |
| TTL-compatible input thresholds | Interfaces directly with legacy 5 V microcontrollers and logic families without level-shifting |
| External timing component flexibility | Supports wide REXT (2 kΩ to 1 MΩ) and unrestricted CEXT values - enables µs to s-range pulses |
Applications
| Industrial Pulse Width Modulation | Legacy System Glue Logic |
|---|---|
Use Scenario: Generating precise, variable-width gate drive pulses for IGBTs in motor control inverters where thermal drift must be minimized. IC Role / Device Role / Timing Role: Dual-channel monostable providing synchronized, retriggerable PWM edge placement with ±0.2 % stability over temperature. Use Value: Eliminates need for microcontroller-based timing firmware and external RC calibration, reducing system latency and code complexity. | Use Scenario: Adding missing one-shot functionality to aging PLC backplanes using discrete 74-series logic. IC Role / Device Role / Timing Role: Replacing multiple discrete 555 timers and logic gates with a single SO16 IC supporting both rising- and falling-edge triggers. Use Value: Reduces component count by >60 % while maintaining full compatibility with existing 5 V TTL signal levels and PCB footprints. |
| Power Sequencing Control | Test Equipment Trigger Synchronization |
Use Scenario: Controlling staggered power-up of FPGA, memory, and analog subsystems in embedded instrumentation. IC Role / Device Role / Timing Role: Providing isolated, resettable delay intervals between enable signals using external R/C networks. Use Value: Ensures reliable sequencing under varying ambient temperatures without recalibration or digital supervision. | Use Scenario: Aligning oscilloscope, DMM, and signal generator triggers in automated test fixtures. IC Role / Device Role / Timing Role: Generating matched, jitter-free trigger pulses from a common reference clock edge. Use Value: Achieves sub-10 ns inter-channel skew and eliminates timing uncertainty caused by software-based delays. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar monostable multivibrator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74HCT4538PW,118 | TSSOP16 package (4.4 mm width); identical electrical specs and pinout | Better thermal performance and smaller footprint; requires fine-pitch reflow process | Select for space-constrained designs where SO16 is unavailable or thermal dissipation is critical |
| SN74LS422N | Single-channel, non-retriggerable, bipolar TTL; no external R/C timing; fixed internal timing | Limited to basic one-shot use; lacks precision, retriggerability, and temperature stability | Only consider for cost-sensitive, low-performance legacy replacements where external timing is undesirable |
Compared with 74HCT4538PW,118, the 74HCT4538D,112 offers identical timing behavior but with SO16 mechanical compatibility for through-hole prototyping and legacy rework; versus SN74LS422N, it delivers retriggerability, ±0.2 % accuracy, and external programmability - making it suitable for precision industrial timing where LS parts fall short.
Availability
74HCT4538D,112 is available at Aetrix Electronics and suitable for industrial motor control, legacy system upgrades, power sequencing, and test equipment requiring stable component supply across extended temperature ranges.
Supply support for 74HCT4538D,112 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
Nexperia is a global semiconductor expert focused on essential efficiency technologies, delivering high-performance logic, analog, and discrete components for industrial, automotive, and consumer markets.
The 74HCT4538 belongs to Nexperia's HCT logic family, designed specifically for 5 V TTL-compatible applications demanding high noise immunity, precise timing, and robust operation across extended industrial temperature ranges.
FAQ
What is the minimum and maximum external timing resistor value supported?
The datasheet specifies REXT from 2 kΩ to 1000 kΩ at VCC = 5.0 V. Values below 2 kΩ risk excessive current draw and timing inaccuracy; above 1000 kΩ increase susceptibility to leakage and noise. For optimal stability, use metal-film resistors with ≤1 % tolerance and low temperature coefficient.
Can both trigger inputs (nA and nB) be used simultaneously on the same channel?
Yes - nA (falling-edge) and nB (rising-edge) are logically OR'd internally per channel. Asserting either input initiates or re-triggers the monostable. This allows flexible edge detection without external logic, supporting mixed-signal interfaces where trigger polarity varies.
How does the device behave during power-down when CEXT holds charge?
Stored energy in CEXT can discharge through input protection diodes into VCC or GND during rapid power loss, risking latch-up or damage. Nexperia recommends adding a Schottky damping diode (DEXT) between nREXT/CEXT and GND, as shown in Figure 10 of the datasheet, to safely bleed residual charge.
Is the 74HCT4538D,112 automotive-qualified?
No - this part is specified for industrial temperature range (–40 °C to +125 °C) but is not AEC-Q100 qualified. Nexperia explicitly states in its legal disclaimers that non-automotive qualified products are unsuitable for safety-critical or life-support applications, including automotive ECUs or ADAS subsystems.
74HCT4538D,112 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- 74HCT
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Monostable
- Independent Circuits:
- 2
- Schmitt Trigger Input:
- No
- Propagation Delay:
- 35 ns
- Current - Output High, Low:
- 4mA, 4mA
- Voltage - Supply:
- 4.5 V ~ 5.5 V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SO
74HCT4538D,112 FAQ
1.How can I place an order for 74HCT4538D,112 through Aetrix?
Please submit a Request for Quotation (RFQ) for 74HCT4538D,112 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 74HCT4538D,112 reliable?
The price and inventory of 74HCT4538D,112 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74HCT4538D,112 is usually 5 days.
3.What payment methods are accepted for 74HCT4538D,112?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74HCT4538D,112 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74HCT4538D,112?
74HCT4538D,112 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74HCT4538D,112 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 74HCT4538D,112?
For technical support, including 74HCT4538D,112 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74HCT4538D,112 requirements.
6.How does Aetrix verify that 74HCT4538D,112 is sourced from the original manufacturer or authorized distributors?
All 74HCT4538D,112 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 74HCT4538D,112 meets industry standards.
7.What is the process for return or replacement of 74HCT4538D,112?
All 74HCT4538D,112 units undergo pre-shipment inspection (PSI). If there is an issue with 74HCT4538D,112, 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 74HCT4538D,112 part is unused and in its original packaging.
Return procedure for 74HCT4538D,112:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
74HCT4538D,112 Tags
-
SN74LVC1G123DCUR
Texas Instruments
-
CD4047BM96
Texas Instruments
-
SN74LVC1G123DCTR
Texas Instruments
-
CD74HC221M96
Texas Instruments
-
CD14538BE
Texas Instruments
-
SN74LVC1G123YZPR
Texas Instruments
-
SN74LVC1G123DCUT
Texas Instruments
-
MC14538BDR2G
onsemi
-
74VHC123AMX
onsemi
-
LTC6993CS6-2#TRMPBF
Analog Devices Inc.
-
LTC6993CS6-3#TRMPBF
Analog Devices Inc.
-
LTC6993CS6-1#TRMPBF
Analog Devices Inc.
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
