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Home > Products > Integrated Circuits (ICs) > Logic > Buffers, Drivers, Receivers, Transceivers

onsemi 74F540PC

Name: 74F540PC
Brand: onsemi
SKU: 74F540PC
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 74F540PC

Manufacturer:: onsemi

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: 20-DIP (0.300", 7.62mm)

Datasheet:: 74F540PC.pdf

Description:: IC BUF NON-INVERT 5.5V 20DIP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

74F540PC from Fairchild Semiconductor is an octal inverting buffer/line driver with 3-STATE outputs, designed for microprocessor output port interfacing. It features active-low dual output enables (OE1, OE2), 20-pin PDIP package, ±0.6 mA input drive capability, and supports 64 mA sink current per output at V_OL ≤ 0.55 V under +5 V supply.

For engineers reviewing the 74F540PC datasheet, pinout, applications, or equivalent options, key selection considerations include its inverting logic function, bus-oriented 3-STATE timing (t_PZH ≤ 8.5 ns), dual enable architecture, and compatibility with TTL-level microprocessor data/address buses.

Technical Context

The 74F540PC implements eight independent inverting buffer stages, each with complementary 3-STATE control via two shared active-low enables (OE1 and OE2). Its pinout places all inputs on one side and outputs on the opposite side of the 20-pin PDIP package-enabling direct microprocessor bus connection without trace crossover.

It operates within +4.5 V to +5.5 V supply range, delivers guaranteed VOL ≤ 0.55 V at IOL = 64 mA, and exhibits propagation delays as low as t_PLH = 1.0 ns and t_PHL = 1.0 ns at TA = 0°C to +70°C with CL = 50 pF.

Key Specifications

Parameter	Value and Actual Design Meaning
Logic Function	Inverting octal buffer with 3-STATE outputs
Supply Voltage	+4.5 V to +5.5 V - compatible with standard TTL and 5 V CMOS systems
Output Drive	−12 mA source / +64 mA sink per output - drives heavy capacitive loads and TTL inputs
Propagation Delay	t_PLH/t_PHL ≤ 5.5 ns max at +25°C - supports high-speed bus timing
Enable Control	Two active-low enables (OE1, OE2) - enables simultaneous or split-group bus control
Input Thresholds	V_IL ≤ 0.8 V, V_IH ≥ 2.0 V - ensures robust noise margin with TTL-compatible signaling
Package	20-Lead PDIP (JEDEC MS-001, 0.300" wide) - through-hole mounting for prototyping and legacy PCBs

Pinout & Package

74F540PC uses a 20-lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001 compliant, 0.300 inch body width, with 0.1 inch lead pitch. Pin 1 is marked by a notch or dot; pin numbering follows standard DIP convention (counter-clockwise from top-left).

Pin/Terminal	Circuit Role	Design Meaning
1, 19	OE1, OE2	Active-low 3-STATE enable inputs - both must be LOW to activate outputs
2–9	I1–I8	Inverting input terminals - drive corresponding outputs with polarity inversion
11–18	O1–O8	Inverting 3-STATE output terminals - high-impedance when either OE is HIGH
10	GND	Ground reference - common return for all signals and power
20	V_CC	Positive supply - +4.5 V to +5.5 V DC power input

Key Features

Feature	Design Value
Inverting buffer logic	Provides signal inversion while buffering - eliminates need for external inverters in bus interface paths
Opposite-side I/O layout	Inputs on pins 2–9, outputs on pins 11–18 - enables straight-through PCB routing from MPU data bus to peripheral bus
Dual active-low enables	OE1 and OE2 allow flexible bus partitioning - e.g., upper/lower byte control or shared enable with other devices
High sink current capability	64 mA per output - directly drives multiple TTL loads or LED indicators without external drivers
Low propagation delay	Typical t_PLH/t_PHL = 2.0 ns - meets timing budgets for 20+ MHz system clocks with setup/hold margin

Applications

Microprocessor System Bus Interface	Industrial I/O Expansion Module
Use Scenario: Connecting an 8-bit microprocessor data bus to peripheral memory or I/O devices requiring inverted and buffered signals. IC Role / Device Role / Timing Role: Inverting octal buffer with 3-STATE control - isolates MPU from bus loading and enables time-multiplexed sharing. Use Value: Eliminates need for discrete inverters and pull-ups; dual OE allows synchronized bus release during DMA cycles.	Use Scenario: Driving 8-channel relay or optocoupler outputs in programmable logic controller (PLC) I/O modules. IC Role / Device Role / Timing Role: High-current line driver - translates logic-level control signals into isolated, load-switching outputs. Use Value: 64 mA sink per channel directly energizes relay coils rated up to 12 V/50 mA without external transistors.
Legacy Instrumentation Backplane	Test Equipment Signal Conditioning
Use Scenario: Interfacing modular instrument controllers to GPIB or IEEE-488-compatible peripheral slots using fixed-width parallel backplanes. IC Role / Device Role / Timing Role: Bus transceiver buffer - provides level-shifting, fan-out expansion, and bus contention protection via 3-STATE control. Use Value: Opposite-side pinout minimizes trace length and crosstalk on dense 0.1" pitch backplanes; PDIP facilitates socket-based field replacement.	Use Scenario: Conditioning digital stimulus signals before injection into analog test circuits, requiring precise edge timing and isolation. IC Role / Device Role / Timing Role: Low-skew inverting driver - ensures matched rise/fall delays across all 8 channels for synchronous pattern generation. Use Value: t_PLH/t_PHL matching ≤ 1 ns guarantees sub-5 ns inter-channel skew - critical for jitter-sensitive ATE applications.

Microprocessor System Bus Interface

Industrial I/O Expansion Module

Use Scenario: Connecting an 8-bit microprocessor data bus to peripheral memory or I/O devices requiring inverted and buffered signals.

IC Role / Device Role / Timing Role: Inverting octal buffer with 3-STATE control - isolates MPU from bus loading and enables time-multiplexed sharing.

Use Value: Eliminates need for discrete inverters and pull-ups; dual OE allows synchronized bus release during DMA cycles.

Use Scenario: Driving 8-channel relay or optocoupler outputs in programmable logic controller (PLC) I/O modules.

IC Role / Device Role / Timing Role: High-current line driver - translates logic-level control signals into isolated, load-switching outputs.

Use Value: 64 mA sink per channel directly energizes relay coils rated up to 12 V/50 mA without external transistors.

Legacy Instrumentation Backplane

Test Equipment Signal Conditioning

Use Scenario: Interfacing modular instrument controllers to GPIB or IEEE-488-compatible peripheral slots using fixed-width parallel backplanes.

IC Role / Device Role / Timing Role: Bus transceiver buffer - provides level-shifting, fan-out expansion, and bus contention protection via 3-STATE control.

Use Value: Opposite-side pinout minimizes trace length and crosstalk on dense 0.1" pitch backplanes; PDIP facilitates socket-based field replacement.

Use Scenario: Conditioning digital stimulus signals before injection into analog test circuits, requiring precise edge timing and isolation.

IC Role / Device Role / Timing Role: Low-skew inverting driver - ensures matched rise/fall delays across all 8 channels for synchronous pattern generation.

Use Value: t_PLH/t_PHL matching ≤ 1 ns guarantees sub-5 ns inter-channel skew - critical for jitter-sensitive ATE applications.

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal inverting buffer applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74F540N	Identical logic function, pinout, and DC/AC specs; manufactured by Texas Instruments with same JEDEC MS-001 PDIP-20 package	No functional difference - fully interchangeable in existing designs with TI-sourced boards	Select SN74F540N when sourcing from TI-authorized channels or when BOM requires TI branding
74ACT540PC	Higher speed (t_PD ≤ 3.5 ns), wider V_CC range (4.5–5.5 V), but higher I_CC (ICCL up to 95 mA); pin-compatible but not logic-identical due to ACT-series input thresholds	Requires verification of input voltage compatibility - V_IL/V_IH thresholds differ (ACT: V_IL ≤ 1.2 V, V_IH ≥ 3.5 V)	Choose 74ACT540PC only when higher speed and CMOS input compatibility are required; not drop-in for TTL-driven systems

Compared with SN74F540N and 74ACT540PC, the 74F540PC offers proven TTL-compatible thresholds, lower static power (ICCL = 53–75 mA), and long-term availability in PDIP for repair and legacy production - making it optimal for cost-sensitive, field-serviceable, or heritage-system designs.

Availability

74F540PC is available at Aetrix Electronics and suitable for microprocessor bus interfacing, industrial I/O expansion, and legacy instrumentation backplane applications requiring stable component supply and through-hole manufacturability.

Supply support for 74F540PC 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

Fairchild Semiconductor was a leading designer and manufacturer of high-performance analog and mixed-signal semiconductors, acquired by ON Semiconductor in 2016; its F logic family remains widely supported and qualified.

The 74F540PC belongs to the Fairchild 74F Fast TTL product line, engineered for high-speed digital systems requiring reliable 3-STATE bus driving with TTL-compatible input levels and robust output drive.

FAQ

What is the logic function of the 74F540PC?

The 74F540PC is an octal inverting buffer with 3-STATE outputs. Each of its eight channels accepts a single input (pins 2–9), inverts it, and drives the corresponding output (pins 11–18) when both OE1 and OE2 are LOW. When either enable is HIGH, the output enters high-impedance state. This behavior is confirmed in the truth table and functional description of the 74F540PC datasheet.

Does the 74F540PC support 3.3 V operation?

No, the 74F540PC is specified only for +4.5 V to +5.5 V supply operation. Its input thresholds (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V) and output drive characteristics are optimized for 5 V TTL systems. Applying 3.3 V to V_CC may result in undefined logic states or insufficient output swing; use 74LVC541 or similar 3.3 V-compatible devices instead.

What is the maximum output sink current for the 74F540PC?

The 74F540PC guarantees a maximum output LOW voltage (V_OL) of 0.55 V when sinking 64 mA per output, as specified in the DC Electrical Characteristics table. This rating applies under V_CC = +5.0 V and ambient temperature 0°C to +70°C. Exceeding 64 mA risks violating VOL spec or exceeding safe operating area limits.

Is the 74F540PC pin-compatible with the 74F541PC?

No, the 74F540PC and 74F541PC are not pin-compatible. Although both are 20-pin PDIP devices with identical package dimensions, the 74F540PC has inverting outputs while the 74F541PC has non-inverting outputs - resulting in different internal signal routing and incompatible functional behavior despite shared pinout geometry.

What does "opposite-side I/O" mean for the 74F540PC?

"Opposite-side I/O" means all eight inputs (pins 2–9) are located on one long edge of the 20-pin PDIP package, while all eight outputs (pins 11–18) are on the opposite edge - enabling direct, orthogonal routing between microprocessor data buses and peripheral connectors without layer transitions or vias. This layout is explicitly documented in the Connection Diagrams section of the 74F540PC datasheet.

74F540PC Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: 74F

Package/Case:: 20-DIP (0.300", 7.62mm)

Packaging:: Tube

Product Status:: Obsolete

Logic Type:: Buffer, Non-Inverting

Number of Elements:: 1

Number of Bits per Element:: 8

Input Type:: -

Output Type:: 3-State

Current - Output High, Low:: 3mA, 64mA

Voltage - Supply:: 4.5V ~ 5.5V

Operating Temperature:: 0°C ~ 70°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 20-PDIP

74F540PC FAQ

1.How can I place an order for 74F540PC through Aetrix?

Please submit a Request for Quotation (RFQ) for 74F540PC 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 74F540PC reliable?

The price and inventory of 74F540PC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74F540PC is usually 5 days.

3.What payment methods are accepted for 74F540PC?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74F540PC transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 74F540PC?

74F540PC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 74F540PC 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 74F540PC?

For technical support, including 74F540PC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74F540PC requirements.

6.How does Aetrix verify that 74F540PC is sourced from the original manufacturer or authorized distributors?

All 74F540PC 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 74F540PC meets industry standards.

7.What is the process for return or replacement of 74F540PC?

All 74F540PC units undergo pre-shipment inspection (PSI). If there is an issue with 74F540PC, 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 74F540PC part is unused and in its original packaging.

Return procedure for 74F540PC:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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