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NXP Semiconductors 74HCT540N,652
- Part No.:
- 74HCT540N,652
- Manufacturer:
- NXP Semiconductors
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
74HCT540N,652.pdf
- Description:
- IC BUFFER INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,294
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Product details
Overview
74HCT540N,652 from NXP Semiconductors is an 8-bit inverting 3-state buffer/line driver with dual active-low output enables (OE1, OE2), designed for bidirectional bus interfacing and address/data line isolation in TTL-compatible digital systems. It operates from 4.5 V to 5.5 V, delivers ±6 mA output drive at VCC = 4.5 V, supports −40 °C to +125 °C industrial temperature range, and features input clamp diodes enabling safe interface to voltages exceeding VCC.
For engineers reviewing the 74HCT540N,652 datasheet, 74HCT540N,652 pinout, 74HCT540N,652 application, or 74HCT540N,652 equivalent, this device serves as a logic-level translation and bus contention control solution in microcontroller peripheral expansion, memory address latching, and legacy TTL system upgrades where inverting 3-state buffering with robust ESD protection (HBM >2000 V) is required.
Technical Context
The 74HCT540N,652 implements standard TTL-compatible input thresholds (VIH = 2.0 V min, VIL = 0.8 V max at VCC = 5 V), ensuring seamless integration with legacy 5 V TTL logic families. Its dual independent output enables allow selective activation of two 4-bit groups or coordinated control of all eight outputs.
Internal architecture includes Schmitt-trigger-free CMOS circuitry with buffered inputs and totem-pole outputs, supporting high-speed operation (tpd = 13 ns typ at VCC = 4.5 V, CL = 50 pF) and low static current (ICC ≤ 160 µA max over full temperature range). The device complies with JEDEC Standard No. 7A and meets IEC 60134 absolute maximum ratings.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Function | Inverting 8-bit buffer with 3-state outputs - provides signal polarity inversion and bus isolation via high-impedance OFF-state. |
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL systems and stable operation across industrial voltage tolerances. |
| Output Drive | ±6.0 mA at VOH/VOL (VCC = 4.5 V) - sufficient to drive multiple 74-series TTL inputs or moderate PCB trace capacitance without external buffers. |
| Propagation Delay | 13 ns typical (An to Yn, VCC = 4.5 V, CL = 50 pF) - enables reliable timing in 30+ MHz bus applications with margin for setup/hold. |
| ESD Protection | HBM >2000 V, MM >200 V - protects against handling damage during assembly and field operation in non-ESD-controlled environments. |
| Operating Temperature | −40 °C to +125 °C - qualified for under-hood automotive modules, industrial PLC backplanes, and extended-range embedded controllers. |
| Input Clamp Diodes | Integrated on all inputs - permits use of series current-limiting resistors when interfacing to signals up to VCC + 0.5 V, preventing latch-up. |
Pinout & Package
DIP20 package (SOT146-1): plastic dual in-line package, 20 leads, 300 mil width, through-hole mounting compatible with standard 0.1″ pitch sockets and wave soldering.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | OE1, OE2 | Active-low output enable inputs - both must be LOW to activate outputs; independent control allows partial bus gating. |
| 2–9 | A0–A7 | Inverting data inputs - each drives corresponding inverted output; TTL-level compatible (2.0 V VIH min). |
| 10 | GND | Ground reference - return path for all internal logic and output currents; requires low-impedance connection to system ground plane. |
| 11–18 | Y0–Y7 | Inverting 3-state outputs - HIGH when enabled and input is LOW; LOW when enabled and input is HIGH; high-Z when either OE is HIGH. |
| 20 | VCC | Positive supply - powers all internal circuitry; requires local 100 nF ceramic decoupling adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-compatible inputs | VIH = 2.0 V min, VIL = 0.8 V max at VCC = 5 V - eliminates need for level-shifting when interfacing with 74LS, 74F, or microcontroller GPIOs operating at 5 V. |
| Dual output enables | Separate OE1 and OE2 pins - enables flexible bus partitioning (e.g., upper/lower nibble control) or redundancy in fault-tolerant designs. |
| Input clamp diodes | Integrated diodes on all A0–A7, OE1, OE2 - allows safe interface to voltages up to VCC + 0.5 V using simple series resistors, reducing BOM count. |
| High noise immunity | Input hysteresis not specified; however, guaranteed VIH/VIL margins (1.2 V noise margin at VCC = 5 V) suppress false triggering in electrically noisy industrial environments. |
| Low quiescent current | ICC ≤ 160 µA max at +125 °C - minimizes standby power in battery-backed or thermally constrained systems without sacrificing speed. |
Applications
| Microcontroller Bus Expansion | Memory Address Latching |
|---|---|
|
Use Scenario: Expanding GPIO count of an 8-bit MCU (e.g., ATmega328P) to drive 16-segment LED displays or parallel LCD modules. IC Role / Device Role / Timing Role: Inverting 3-state buffer isolating MCU port pins from display data bus; OE lines synchronized with write strobe for glitch-free updates. Use Value: Prevents bus contention during multi-cycle writes and enables shared data bus between display and other peripherals using OE arbitration. |
Use Scenario: Driving 16-bit address lines of SRAM or EPROM in an 8051-based embedded controller with limited address latch resources. IC Role / Device Role / Timing Role: Inverting buffer for upper address byte (A8–A15); OE controlled by memory select signal to gate address during I/O cycles. Use Value: Eliminates need for discrete inverters and reduces propagation delay skew versus discrete transistor solutions, improving address setup time margin. |
| Legacy TTL System Upgrade | Industrial I/O Module Isolation |
|
Use Scenario: Replacing obsolete 74LS540 in a factory automation PLC backplane where board space and thermal budget constrain redesign options. IC Role / Device Role / Timing Role: Pin-compatible 3-state buffer providing identical logic function with lower power and higher noise immunity than LS-TTL. Use Value: Enables drop-in replacement without layout changes while reducing board-level heat generation and improving reliability at elevated ambient temperatures. |
Use Scenario: Isolating programmable logic controller (PLC) CPU bus from field I/O expansion racks subject to EMI and ground potential differences. IC Role / Device Role / Timing Role: Bidirectional bus buffer with OE controlled by rack-select decoder; clamped inputs tolerate induced transients on long inter-rack cables. Use Value: Prevents cross-talk and latch-up during hot-swap events and extends system uptime in electrically harsh plant-floor environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8-bit inverting 3-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT540N | TI-manufactured part with identical pinout, electrical specs, and JEDEC 7A compliance; propagation delay 14 ns typ (vs. 13 ns for NXP) at same conditions. | Same functional role in TTL-bus systems; validated in TI's industrial reference designs for PLC I/O modules. | Select when sourcing from TI-authorized distributors or requiring TI-specific qualification documentation. |
| 74VHC540N | Higher-speed CMOS variant (VHC family); VIH/VIL thresholds CMOS-level (70 %/30 % VCC), not TTL-compatible; tpd = 7.5 ns typ at VCC = 5 V. | Requires level-shifting if interfacing with true TTL sources; suitable only in pure CMOS or mixed-voltage systems with careful input threshold management. | Choose only when speed >20 MHz is mandatory and all driving sources meet CMOS input voltage requirements. |
Compared with SN74HCT540N and 74VHC540N, the 74HCT540N,652 offers optimal balance of TTL compatibility, industrial temperature support, and proven field reliability in legacy-system upgrades-whereas SN74HCT540N provides second-source assurance, and 74VHC540N trades compatibility for raw speed in CMOS-native designs.
Availability
74HCT540N,652 is available at Aetrix Electronics and suitable for microcontroller bus expansion, memory address latching, and legacy TTL system upgrades requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for 74HCT540N,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 company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and IoT applications.
The 74HCT540N,652 belongs to NXP's legacy HC/HCT logic family, engineered for robust interoperability with TTL and CMOS systems in industrial control, instrumentation, and embedded computing where reliability and long-term availability are critical.
FAQ
What is the maximum supply voltage rating for the 74HCT540N,652?
The 74HCT540N,652 has an absolute maximum supply voltage (VCC) of +7.0 V per NXP's limiting values table. However, recommended operating conditions specify 4.5 V to 5.5 V. Operating above 5.5 V risks violating input/output voltage margins and may accelerate parametric drift or reduce long-term reliability. Always maintain VCC within 4.5 V–5.5 V for compliant 5 V TTL system operation.
Does the 74HCT540N,652 support hot insertion or live bus connection?
The 74HCT540N,652 is not explicitly rated for hot insertion. While its input clamp diodes and 3-state outputs mitigate some stress during live connection, the device lacks bus-hold or powered-off protection features. For reliable hot-plug operation, external series resistors (≥100 Ω) and RC filtering on OE and data lines are recommended, and system-level sequencing must ensure VCC is stable before asserting OE or applying inputs.
Can the 74HCT540N,652 drive a 50 pF load at 20 MHz without signal degradation?
Yes. With tpd = 13 ns typical and tt = 5 ns typical (transition time) at VCC = 4.5 V and CL = 50 pF, the 74HCT540N,652 supports clean edges up to ~35 MHz fundamental frequency. At 20 MHz, rise/fall times remain well within specification, and output drive (±6 mA) ensures adequate slew rate into 50 pF. Maintain proper PCB layout: short traces, ground plane, and local decoupling to preserve signal integrity.
How do OE1 and OE2 interact in the 74HCT540N,652 functional logic?
In the 74HCT540N,652, both OE1 and OE2 must be LOW for any output (Y0–Y7) to be active. If either OE1 or OE2 is HIGH, all eight outputs enter high-impedance state regardless of input states. This OR logic means OE1 and OE2 are wired in parallel for full-bus control or used independently to gate subsets of outputs only if external logic combines them - the device itself does not decode separate enable groups.
Is the 74HCT540N,652 suitable for automotive applications?
No. The 74HCT540N,652 is not automotive-qualified. Though it operates from −40 °C to +125 °C, NXP explicitly states in its legal disclaimers that non-automotive qualified products lack AEC-Q100 testing, automotive-grade screening, or guaranteed PPAP compliance. Use only in industrial, commercial, or consumer systems; for automotive ECUs or body control modules, select NXP's automotive-qualified alternatives such as the 74AHCT540.
74HCT540N,652 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- 74HCT
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Buffer, Inverting
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 6mA, 6mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-DIP
74HCT540N,652 FAQ
1.How can I place an order for 74HCT540N,652 through Aetrix?
Please submit a Request for Quotation (RFQ) for 74HCT540N,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 74HCT540N,652 reliable?
The price and inventory of 74HCT540N,652 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74HCT540N,652 is usually 5 days.
3.What payment methods are accepted for 74HCT540N,652?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74HCT540N,652 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74HCT540N,652?
74HCT540N,652 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74HCT540N,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 74HCT540N,652?
For technical support, including 74HCT540N,652 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74HCT540N,652 requirements.
6.How does Aetrix verify that 74HCT540N,652 is sourced from the original manufacturer or authorized distributors?
All 74HCT540N,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 74HCT540N,652 meets industry standards.
7.What is the process for return or replacement of 74HCT540N,652?
All 74HCT540N,652 units undergo pre-shipment inspection (PSI). If there is an issue with 74HCT540N,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 74HCT540N,652 part is unused and in its original packaging.
Return procedure for 74HCT540N,652:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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