My Inquiry
My Account
Nexperia USA Inc. 74HC4538D,652
- Part No.:
- 74HC4538D,652
- Manufacturer:
- Nexperia USA Inc.
- Category:
- Multivibrators
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
74HC4538D,652.pdf
- Description:
- IC MULTIVIBRATOR 25NS 16SO
- Quantity:
- Payment:
- Shipping:
Inventory:4,766
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
74HC4538D,652 from Nexperia is a dual retriggerable-resettable precision monostable multivibrator in SO16 package, operating from 2.0 V to 6.0 V, delivering ±0.2 % pulse width stability over -40 °C to +125 °C, with output pulse width defined by external REXT and CEXT (TW = 0.7 × REXT × CEXT), and supporting both rising- and falling-edge triggering for timing-critical digital control circuits.
For engineers reviewing the 74HC4538D,652 datasheet, 74HC4538D,652 pinout, 74HC4538D,652 application, or 74HC4538D,652 equivalent, this device serves as a precision timing element in pulse generation, debouncing, delay insertion, and event synchronization where deterministic, retriggerable one-shot behavior and temperature-stable pulse widths are required.
Technical Context
The 74HC4538D implements two independent monostable circuits, each with dual edge-trigger inputs (nA for falling-edge, nB for rising-edge), active-low direct reset (nCD), complementary outputs (nQ/nQ), and dedicated external timing pins (nREXT/CEXT and nCEXT). Its linear design ensures precise pulse width control unaffected by supply voltage variation.
Schmitt-trigger inputs tolerate slow signal edges, and internal clamp diodes allow interfacing to voltages exceeding VCC using current-limiting resistors. The device supports retriggering during an active output pulse, enabling dynamic pulse extension without requiring external logic.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2.0 V to 6.0 V - Enables interoperability with 3.3 V and 5 V logic families and mixed-voltage systems. |
| Pulse Width Accuracy | ±0.2 % over temperature - Ensures stable timing in industrial environments without recalibration. |
| Output Pulse Width Formula | TW = 0.7 × REXT × CEXT - Directly sets timing via passive component selection; no internal oscillator or trimming required. |
| Propagation Delay (VCC = 4.5 V) | 27 ns to 80 ns - Supports high-speed timing applications up to ~10 MHz effective trigger rate. |
| Operating Temperature Range | -40 °C to +125 °C - Qualified for under-hood automotive modules, motor drives, and industrial PLCs. |
| Input Edge Sensitivity | Falling edge on nA, rising edge on nB - Allows flexible trigger source selection without external inverters. |
| Reset Response Time | ≤24 ns (VCC = 6.0 V) - Guarantees sub-25 ns termination of active pulses for fail-safe timing control. |
Pinout & Package
74HC4538D,652 is housed in a plastic small outline package (SO16, SOT109-1) with 16 leads and 3.9 mm body width, optimized for automated PCB assembly and thermal performance in high-density layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 15 (1CEXT, 2CEXT) | External capacitor connection | Must be connected to GND; forms RC timing network with pin 2/14 for pulse width definition. |
| 2, 14 (1REXT/CEXT, 2REXT/CEXT) | External resistor/capacitor node | Connects REXT in series with CEXT (pin 1/15) to set TW = 0.7 × REXT × CEXT per channel. |
| 3, 13 (1CD, 2CD) | Direct reset input | Active LOW; forces immediate termination of output pulse regardless of trigger state. |
| 4, 12 (1B, 2B) | Rising-edge trigger input | Triggers monostable on HIGH-to-LOW transition; compatible with standard logic outputs. |
| 5, 11 (1A, 2A) | Falling-edge trigger input | Triggers monostable on LOW-to-HIGH transition; enables asynchronous edge detection. |
| 6, 10 (1Q, 2Q) | True output | Active HIGH pulse output; synchronized to trigger edge and timed by external RC network. |
| 7, 9 (1Q, 2Q) | Complementary output | Active LOW counterpart to 1Q/2Q; provides differential timing signals without external inverters. |
| 8 | GND | Reference ground for all I/O and power connections; must be low-impedance for timing stability. |
| 16 | VCC | Positive supply rail; decoupling capacitor (100 nF) recommended near pin for noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent monostables | Enables two synchronized or isolated timing functions in one IC - reduces board space vs discrete 555 solutions. |
| Retriggerable operation | Allows extending active pulse duration mid-cycle - critical for variable-width pulse generation in encoder interfaces. |
| Schmitt-trigger inputs | Accepts slow-rising signals (≥83 ns/V at VCC = 2.0 V) without false triggering - eliminates need for external signal conditioning. |
| CMOS input levels & low power | Draws ≤160 μA ICC at VCC = 6.0 V - suitable for battery-backed timing and low-power sensor nodes. |
| Clamp diode protection | Permits safe interface to voltages > VCC using series resistors - simplifies level-shifting in mixed-supply systems. |
Applications
| Encoder Debouncing | Pulse Width Modulation Control |
|---|---|
Use Scenario: Mechanical rotary encoder outputs generate contact bounce causing multiple false counts in microcontroller quadrature decoding. IC Role / Device Role / Timing Role: Monostable channel acts as hardware debounce filter, generating clean, fixed-duration pulses aligned to valid encoder transitions. Use Value: Eliminates software polling or timer-based debounce routines; guarantees ≤20 ns jitter between bounce suppression and output stabilization. | Use Scenario: Microcontroller GPIO lacks sufficient PWM resolution or drive strength for analog dimming of high-brightness LEDs. IC Role / Device Role / Timing Role: One-shot generates precise ON-time pulses triggered by MCU edge outputs; duty cycle controlled by varying trigger frequency. Use Value: Achieves 12-bit effective resolution using external REXT/CEXT tuning; avoids MCU resource contention and firmware latency. |
| Industrial Safety Interlock | Serial Data Glitch Filtering |
Use Scenario: Emergency stop circuit requires guaranteed pulse termination within 25 ns if a fault condition occurs during active timing window. IC Role / Device Role / Timing Role: Active-low nCD input directly connects to safety PLC output; forces immediate nQ deassertion on fault assertion. Use Value: Meets SIL-2 response time requirements (<50 ns) without FPGA or ASIC implementation; deterministic hardware-level shutdown. | Use Scenario: RS-485 bus receiver outputs exhibit sub-microsecond glitches due to EMI coupling, corrupting UART frame sync. IC Role / Device Role / Timing Role: Monostable configured with 100 ns TW filters out narrow noise spikes while passing valid data pulses ≥500 ns wide. Use Value: Prevents UART framing errors without altering protocol or adding software CRC overhead; operates transparently in-line. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar monostable multivibrator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74HC4538PW,118 | TSSOP16 package (SOT403-1); 4.4 mm body width; 1.2 mm max height; slightly higher thermal resistance. | Better suited for ultra-dense PCBs with fine-pitch routing; lower profile allows stacking with adjacent components. | Select when board space or component height is constrained; verify thermal derating above 91 °C. |
| SN74LV123APWR | Single-channel LV-CMOS device; 1.65 V to 5.5 V supply; no retriggerable mode; fixed internal timing architecture. | Limited to non-retriggerable one-shot use; requires external logic for pulse extension; lower propagation delay (13 ns typ). | Choose only for simple, non-retriggerable timing where supply voltage < 2.0 V is needed or ultra-low delay is critical. |
Compared with 74HC4538PW,118, the 74HC4538D,652 offers superior thermal dissipation in SO16 and broader industrial temperature margin; versus SN74LV123APWR, it delivers true retriggerability and dual-channel integration essential for encoder and safety interlock designs.
Availability
74HC4538D,652 is available at Aetrix Electronics and suitable for industrial automation, motor control, and embedded safety systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for 74HC4538D,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
Nexperia is a global semiconductor expert focused on high-volume, high-reliability logic, analog, and MOSFET solutions for automotive, industrial, and consumer markets.
The 74HC4538 belongs to Nexperia's HC logic family, designed specifically for precision timing applications demanding retriggerable behavior, wide supply range, and robust operation in harsh environments.
FAQ
What is the minimum external resistor value supported for stable pulse width generation?
The datasheet specifies REXT from 2 kΩ to 1000 kΩ at VCC = 5.0 V. Below 2 kΩ, timing accuracy degrades due to internal node loading and reduced drive capability; verified operation starts at 2.2 kΩ with ≤1 % deviation in TW across temperature. Values below 1.8 kΩ risk metastability in the internal timing comparator.
Can 74HC4538D,652 generate asymmetric pulses using a single RC network?
No - each monostable channel requires its own dedicated REXT and CEXT pair. The device does not support shared timing components between channels; cross-channel interference would occur due to internal node coupling. Asymmetric pulses require separate RC networks per channel or external gating logic.
Is the 74HC4538D,652 qualified for automotive applications?
No - although rated for -40 °C to +125 °C, it is not AEC-Q100 qualified and lacks automotive-specific reliability testing (e.g., HTOL, ESD HBM ≥8 kV). Nexperia explicitly states non-automotive qualification in Section 15; use only in industrial or commercial systems unless validated per customer-specific automotive requirements.
How does the device behave when CEXT is disconnected or left floating?
Leaving CEXT unconnected causes undefined output behavior: the internal timing node floats, leading to erratic pulse widths, failure to trigger, or sustained oscillation. The datasheet mandates connection of CEXT to GND (pins 1/15) and REXT to pin 2/14; floating CEXT violates Absolute Maximum Ratings and may induce latch-up per JESD78 Class II Level B test conditions.
74HC4538D,652 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Nexperia USA Inc.
- Series:
- 74HC
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Logic Type:
- Monostable
- Independent Circuits:
- 2
- Schmitt Trigger Input:
- No
- Propagation Delay:
- 25 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:
- Surface Mount
- Supplier Device Package:
- 16-SO
74HC4538D,652 FAQ
1.How can I place an order for 74HC4538D,652 through Aetrix?
Please submit a Request for Quotation (RFQ) for 74HC4538D,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 74HC4538D,652 reliable?
The price and inventory of 74HC4538D,652 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74HC4538D,652 is usually 5 days.
3.What payment methods are accepted for 74HC4538D,652?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74HC4538D,652 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74HC4538D,652?
74HC4538D,652 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74HC4538D,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 74HC4538D,652?
For technical support, including 74HC4538D,652 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74HC4538D,652 requirements.
6.How does Aetrix verify that 74HC4538D,652 is sourced from the original manufacturer or authorized distributors?
All 74HC4538D,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 74HC4538D,652 meets industry standards.
7.What is the process for return or replacement of 74HC4538D,652?
All 74HC4538D,652 units undergo pre-shipment inspection (PSI). If there is an issue with 74HC4538D,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 74HC4538D,652 part is unused and in its original packaging.
Return procedure for 74HC4538D,652:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
74HC4538D,652 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
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…
LDO regulator guide covering low dropout voltage, power dissipation, thermal design, PSRR, output noise, capacitor stability, adjustable LDO circuits, LDO vs buck converter and datasheet selection chec…
Conditional Access Module guide covering CAM meaning, CI/CI+ interface, smart card authorization, DVB security workflow, TV and set-top box compatibility, internal electronics, ESD protection, connecto…
Guide to electronic component obsolescence covering EOL risk, PCN/PDN notices, last-time buy planning, replacement options, form-fit-function validation, counterfeit risk and BOM lifecycle management.
18650 battery guide covering lithium-ion cell basics, 3.6V/3.7V voltage, 4.2V charging, mAh and Wh capacity, protected cells, chargers, BMS, series-parallel packs, holders, welding and sourcing checks.…
Hall effect sensor guide covering working principle, linear and digital sensors, Arduino circuits, current sensing, speed detection, automotive applications, A3144 examples, signal filtering and datash…
Product Change Notification guide for electronic components, covering PCN meaning, PCN vs PDN/EOL, common change types, risk levels, form-fit-function review, engineering validation, BOM control, LTB/L…
A practical guide to blend door actuators, covering HVAC function, symptoms, location, AC and heater issues, reset and calibration, replacement cost, electrical diagnosis, compatibility checks, and rep…
Engineering guide to Raspberry Pi alternatives, covering chip-level differences, Orange Pi, ROCK, Jetson, Banana Pi, NanoPi, Compute Module, Pico, GPIO, camera, HAT compatibility, and replacement risks…
Engineering guide to dynamic load response testing for high-current buck converters, covering load step setup, slew rate, Vcore undershoot, overshoot, recovery time, probe location, output capacitors a…
