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Toshiba Semiconductor and Storage TC74HC540AF(EL,F)
- Part No.:
- TC74HC540AF(EL,F)
- Manufacturer:
- Toshiba Semiconductor and Storage
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
TC74HC540AF(EL,F).pdf
- Description:
- IC BUFFER INVERT 6V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,264
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Product details
Overview
TC74HC540AF(EL,F) from Toshiba is an octal inverting 3-state bus buffer IC used for bidirectional data bus isolation and signal conditioning in digital logic systems. It operates from 2 V to 6 V, delivers 6 mA output drive per channel, features 10 ns typical propagation delay at 5 V, and supports high-impedance output control via dual enable inputs (1G, 2G). It is commonly deployed in microcontroller peripheral interfacing and legacy TTL-compatible backplane drivers.
For engineers reviewing the TC74HC540AF(EL,F) datasheet, TC74HC540AF(EL,F) pinout, TC74HC540AF(EL,F) application, or TC74HC540AF(EL,F) equivalent, key selection criteria include its inverting 3-state behavior, LSTTL-load compatibility (15 loads), symmetrical output impedance, wide supply range, and SOP20 package suitability for space-constrained PCB layouts.
Technical Context
The TC74HC540AF(EL,F) implements eight independent inverting buffers, each with three-state output control governed by two active-low enable inputs (1G and 2G). When either enable is high, all corresponding outputs enter high-impedance state-enabling shared-bus arbitration without external logic.
It uses silicon gate C2MOS technology to achieve LSTTL-speed performance (tpd = 10 ns typ. at VCC = 5 V) while maintaining CMOS-level quiescent current (ICC ≤ 4 μA max at 25°C). Input thresholds are specified as VIH ≥ 2.0 V and VIL ≤ 0.8 V at VCC = 4.5 V, ensuring robust noise immunity (VNIH/VNIL ≥ 28% VCC).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Function | Inverting octal buffer with dual 3-state enable (1G, 2G) |
| Supply Voltage Range | 2.0 V to 6.0 V - supports mixed-voltage system interfacing |
| Propagation Delay | 10 ns (typ.) at VCC = 5 V - enables reliable operation up to ~35 MHz clock domains |
| Output Drive | ±6 mA min per output - drives 15 LSTTL loads directly |
| Quiescent Current | 4 μA max at Ta = 25°C - suitable for low-power standby modes |
| Input Noise Immunity | ≥28% VCC - reduces susceptibility to ground bounce and crosstalk |
| Operating Temperature | −40°C to +85°C - qualified for industrial-grade embedded applications |
Pinout & Package
SOP20-P-300-1.27A surface-mount package (20-pin, 1.27 mm pitch, 7.6 mm × 12.8 mm body); RoHS-compliant, tape-and-reel packaging (EL,F suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1G, 2G | Active-low output enable inputs | Both must be low for enabled (inverting) output; either high forces all Yn outputs to high-Z |
| A1–A8 | Input terminals | Eight buffered inputs driving inverted outputs Y1–Y8 |
| Y1–Y8 | Inverting 3-state outputs | Outputs mirror A1–A8 with inversion; tri-stated when 1G or 2G = high |
| VCC | Positive supply | 2.0–6.0 V DC; decoupling capacitor required near pin |
| GND | Ground reference | Common return for inputs, outputs, and supply |
Key Features
| Feature | Design Value |
|---|---|
| Pin- and function-compatible with 74LS540 | Enables drop-in replacement in legacy LSTTL designs without layout change |
| Symmetrical output drive (|IOH| = IOL = 6 mA min) | Ensures matched rise/fall times and predictable timing margins |
| Balanced propagation delays (tpLH ≈ tpHL) | Minimizes duty-cycle distortion in clocked or bidirectional data paths |
| Wide VCC range (2–6 V) | Supports direct interface between 3.3 V controllers and 5 V peripherals |
| ESD-protected inputs | Withstands ±20 mA input diode current - improves board-level handling robustness |
Applications
| Microcontroller Bus Expansion | Industrial PLC I/O Module |
|---|---|
|
Use Scenario: Expanding GPIO count of an ARM Cortex-M0+ MCU to drive 8-bit parallel LCD and keypad interface. IC Role / Device Role / Timing Role: Inverting 3-state buffer isolating MCU data bus from display controller during read cycles. Use Value: Enables bidirectional data flow control using dual enable pins, eliminating need for external direction logic. |
Use Scenario: Level-shifting and bus buffering between 3.3 V FPGA configuration logic and 5 V relay driver bank. IC Role / Device Role / Timing Role: Octal inverting buffer providing voltage translation and current gain for discrete transistor switching. Use Value: Delivers 6 mA per output to saturate BC337 transistors without external drivers, reducing BOM count. |
| Legacy Instrument Backplane | Test Equipment Signal Routing |
|
Use Scenario: Replacing obsolete 74LS540 in aging benchtop oscilloscope mainboard for address/data bus isolation. IC Role / Device Role / Timing Role: Pin-compatible CMOS upgrade delivering same logic function with lower power and higher noise margin. Use Value: Reduces board power dissipation by >90% versus LS-TTL while maintaining full timing compliance. |
Use Scenario: Configurable signal path routing in automated test equipment (ATE) where multiple DUT interfaces share a common bus. IC Role / Device Role / Timing Role: 3-state buffer enabling dynamic bus partitioning under microcontroller control. Use Value: Dual enable inputs allow independent control of two 4-bit groups, supporting flexible test pattern sequencing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting bus buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HC540N | DIP20 package only; identical AC/DC specs but lacks SOP20 footprint | Preferred for through-hole prototyping or legacy DIP-based systems | Select when mechanical compatibility with existing DIP sockets is required |
| 74VHC540M | Higher speed (tpd = 7.5 ns typ. at 5 V); tighter VOH/VOL specs; same SOP20 pinout | Better suited for 50 MHz+ data strobes or tighter setup/hold timing budgets | Choose when marginal timing margins exist in high-frequency bus designs |
Compared with SN74HC540N and 74VHC540M, the TC74HC540AF(EL,F) offers optimal balance of industrial temperature range, SOP20 compactness, and proven reliability in long-lifecycle instrumentation - making it preferred for volume production where footprint and thermal profile are constrained.
Availability
TC74HC540AF(EL,F) is available at Aetrix Electronics and suitable for industrial PLC I/O modules, test equipment signal routing, and microcontroller bus expansion requiring stable component supply across extended product lifecycles.
Supply support for TC74HC540AF(EL,F) 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
Toshiba Electronic Devices & Storage Corporation designs and manufactures high-reliability semiconductor components for industrial, automotive, and consumer applications, with over 35 years of CMOS logic leadership.
The TC74HC540AF(EL,F) belongs to Toshiba's HC-series high-speed CMOS logic family, engineered specifically for pin-compatible upgrades of legacy TTL bus interfaces while delivering lower power, wider voltage tolerance, and enhanced noise immunity.
FAQ
What is the logic function of the TC74HC540AF(EL,F)?
The TC74HC540AF(EL,F) is an octal inverting 3-state bus buffer. It accepts eight digital inputs (A1–A8) and produces inverted, high-impedance-capable outputs (Y1–Y8). Its dual enable inputs (1G and 2G) allow simultaneous tri-state control of all outputs - a critical feature for shared-bus architectures. This exact functionality is confirmed in Toshiba's official datasheet truth table and IEC logic symbol.
Does the TC74HC540AF(EL,F) support 3.3 V operation?
Yes, the TC74HC540AF(EL,F) operates across 2.0 V to 6.0 V, fully supporting 3.3 V nominal supply. At VCC = 3.3 V, VIH is guaranteed ≥ 2.0 V and VIL ≤ 1.35 V, ensuring interoperability with standard 3.3 V CMOS logic families. This specification is explicitly listed in the "Electrical Characteristics" table of the Toshiba datasheet.
What package type does TC74HC540AF(EL,F) use?
The TC74HC540AF(EL,F) uses the SOP20-P-300-1.27A package: a 20-pin small-outline plastic package with 1.27 mm lead pitch, 7.6 mm body width, and tape-and-reel delivery (denoted by "EL,F" suffix). This matches Toshiba's official package dimension drawing and weight specification (0.22 g typ.).
How does the TC74HC540AF(EL,F) compare to the non-inverting TC74HC541AF(EL,F)?
The TC74HC540AF(EL,F) provides inverting logic (Yn = NOT An), whereas TC74HC541AF(EL,F) is non-inverting (Yn = An). Both share identical pinout, 3-state control, AC/DC specs, and SOP20 packaging. The choice depends strictly on signal polarity requirements in the target bus architecture - no electrical or mechanical differentiation exists beyond inversion.
Is the TC74HC540AF(EL,F) compatible with 74LS540-based designs?
Yes - the TC74HC540AF(EL,F) is explicitly stated in Toshiba's datasheet as "pin and function compatible with 74LS540". It replicates the same pin assignment, truth table, and 3-state behavior while improving speed (10 ns vs. 15 ns), reducing ICC (μA vs. mA), and widening VCC range (2–6 V vs. 4.75–5.25 V), making it a direct drop-in upgrade.
TC74HC540AF(EL,F) Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Toshiba Semiconductor and Storage
- Series:
- 74HC
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Logic Type:
- Buffer, Inverting
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 7.8mA, 7.8mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOP
TC74HC540AF(EL,F) FAQ
1.How can I place an order for TC74HC540AF(EL,F) through Aetrix?
Please submit a Request for Quotation (RFQ) for TC74HC540AF(EL,F) 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 TC74HC540AF(EL,F) reliable?
The price and inventory of TC74HC540AF(EL,F) are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TC74HC540AF(EL,F) is usually 5 days.
3.What payment methods are accepted for TC74HC540AF(EL,F)?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TC74HC540AF(EL,F) transactions.
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4.How is shipping managed for TC74HC540AF(EL,F)?
TC74HC540AF(EL,F) orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TC74HC540AF(EL,F) 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 TC74HC540AF(EL,F)?
For technical support, including TC74HC540AF(EL,F) datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TC74HC540AF(EL,F) requirements.
6.How does Aetrix verify that TC74HC540AF(EL,F) is sourced from the original manufacturer or authorized distributors?
All TC74HC540AF(EL,F) 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 TC74HC540AF(EL,F) meets industry standards.
7.What is the process for return or replacement of TC74HC540AF(EL,F)?
All TC74HC540AF(EL,F) units undergo pre-shipment inspection (PSI). If there is an issue with TC74HC540AF(EL,F), 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 TC74HC540AF(EL,F) part is unused and in its original packaging.
Return procedure for TC74HC540AF(EL,F):
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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