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

Texas Instruments 85505012A

Name: 85505012A
Brand: Texas Instruments
SKU: 85505012A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 85505012A

Manufacturer:: Texas Instruments

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: -

Datasheet:: 85505012A.pdf

Description:: SN54HCT240 OCTAL BUFFERS AND LIN

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Product details

Overview

85505012A from Texas Instruments is a military-grade octal inverting 3-state buffer/driver IC designed for high-reliability memory address and bus driving applications. It operates from 4.5 V to 5.5 V, delivers ±6-mA output drive at 5 V, exhibits typical propagation delay of 12 ns, and supports −55°C to +125°C operation in LCCC-FK package.

For engineers reviewing the 85505012A datasheet, 85505012A pinout, 8505012A application, or 85505012A equivalent, key selection criteria include its TTL-compatible inputs, high-current 3-state outputs capable of driving 15 LSTTL loads, low 80-µA max ICC power consumption, and qualification per MIL-PRF-38535 Class B for defense and aerospace systems.

Technical Context

The 85505012A implements two independent 4-bit inverting buffer sections, each with dedicated active-low output-enable (OE) control. Its logic function inverts input data when OE is low and places outputs in high-impedance state when OE is high - enabling bidirectional bus management without external direction control.

Designed for compatibility with TTL voltage levels, it features 1 µA max input current, ±35 mA continuous output current capability, and absolute maximum ratings including −0.5 V to 7 V supply voltage and −65°C to +150°C storage temperature - confirming suitability for harsh-environment deployment.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage	4.5 V to 5.5 V - ensures stable operation across industrial and military power rail tolerances.
Propagation Delay	12 ns typical at 5.5 V, CL = 50 pF - enables high-speed address/data buffering in real-time control systems.
Output Drive	±6 mA at 5 V - directly interfaces with 15 LSTTL loads without external amplification.
Quiescent Current	80 µA max ICC - minimizes standby power in battery-backed or thermally constrained modules.
Operating Temperature	−55°C to +125°C - certified for extended-range operation in avionics, engine control, and space-qualified electronics.
Input Compatibility	TTL-voltage compatible - eliminates level-shifting requirements when interfacing legacy TTL logic.
3-State Leakage	±10 µA max IOZ - maintains bus integrity during high-impedance mode with negligible signal contention.

Pinout & Package

LCCC (Leadless Chip Carrier) package, FK outline, 20-terminal ceramic hermetic construction with J-lead geometry and center ground/power pad - optimized for thermal dissipation and EMI resilience in high-reliability PCBs.

Pin/Terminal	Circuit Role	Design Meaning
1OE	Active-low enable for first 4-bit inverting buffer	Controls Y1–Y4 output state; low = invert A1–A4, high = high-Z.
1A1–1A4	Inputs to first inverting buffer section	Accept TTL-level signals; drive inverted outputs to Y1–Y4 when 1OE is low.
1Y1–1Y4	Inverted outputs of first buffer section	Provide ±6 mA drive; enter high-impedance state when 1OE is high.
2OE	Active-low enable for second 4-bit inverting buffer	Independent control of Y1–Y4 outputs; enables dual-bus isolation.
2A1–2A4	Inputs to second inverting buffer section	Electrically isolated from first section; support concurrent address/data path separation.
2Y1–2Y4	Inverted outputs of second buffer section	Match 1Yx timing and drive strength; allow synchronized dual-bank buffering.
VCC	Positive supply terminal	Must be decoupled locally; supports 4.5–5.5 V with ≤70 mA total current draw.
GND	Ground reference terminal	Shared return for all I/O and supply currents; requires low-inductance connection.

Key Features

Feature	Design Value
High-Reliability Qualification	MIL-PRF-38535 Class B certified - meets screening, testing, and traceability requirements for defense/aerospace programs.
Dual Independent 3-State Control	Separate 1OE and 2OE pins - enables selective activation of either 4-bit buffer bank without affecting the other.
Low-Power TTL-Compatible Interface	1 µA max input current and 80 µA max ICC - reduces loading on upstream drivers and system-level power budget.
Robust Output Stage	±35 mA continuous output current rating - withstands transient bus faults and ESD events without latch-up.
Hermetic LCCC Packaging	Ceramic FK package with solder-sealed lid - provides moisture resistance and long-term reliability in vacuum or high-humidity environments.

Applications

Avionics Data Bus Interface	Secure Military Communication Controller
Use Scenario: Isolating and buffering address lines between FPGA-based mission computers and radiation-hardened SRAM modules in flight control systems. IC Role / Device Role / Timing Role: 85505012A acts as a dual-channel inverting address driver with independent 3-state control, synchronizing memory access while preventing bus contention during context switches. Use Value: Its −55°C to +125°C operation and MIL-qualified LCCC package ensure uninterrupted functionality under extreme thermal cycling and vibration encountered in aircraft and UAV platforms.	Use Scenario: Managing bidirectional data flow between encryption ASICs and secure radio transceivers in tactical handheld radios. IC Role / Device Role / Timing Role: 85505012A serves as a controlled-direction bus transceiver, using separate OE pins to isolate transmit/receive paths and eliminate timing skew between cipher and RF subsystems. Use Value: The 12 ns typical tpd and ±6 mA drive guarantee deterministic latency and signal integrity across encrypted data bursts, meeting STANAG 4285 timing compliance.
Spacecraft Onboard Computer Backplane	Nuclear Power Plant Safety PLC I/O Module
Use Scenario: Driving parallel address buses across multi-board backplanes in satellite onboard computers where radiation tolerance and zero failure rate are mandatory. IC Role / Device Role / Timing Role: 85505012A functions as a radiation-tolerant address demultiplexer, leveraging its hermetic LCCC package and 3-state outputs to prevent single-event latch-up during solar particle events. Use Value: Its qualified MIL-PRF-38535 Class B status and −65°C to +150°C storage range support 15+ year orbital missions without derating or redundancy overhead.	Use Scenario: Buffering critical trip-signal lines between redundant safety processors and analog I/O cards in nuclear reactor protection systems. IC Role / Device Role / Timing Role: 85505012A provides fail-safe 3-state isolation between processor banks, ensuring no spurious output activation during processor reset or diagnostic self-test sequences. Use Value: The 80 µA max ICC and ±10 µA max IOZ guarantee minimal leakage-induced false trips, satisfying IEC 61508 SIL-3 hardware fault tolerance requirements.

Avionics Data Bus Interface

Secure Military Communication Controller

Use Scenario: Isolating and buffering address lines between FPGA-based mission computers and radiation-hardened SRAM modules in flight control systems.

IC Role / Device Role / Timing Role: 85505012A acts as a dual-channel inverting address driver with independent 3-state control, synchronizing memory access while preventing bus contention during context switches.

Use Value: Its −55°C to +125°C operation and MIL-qualified LCCC package ensure uninterrupted functionality under extreme thermal cycling and vibration encountered in aircraft and UAV platforms.

Use Scenario: Managing bidirectional data flow between encryption ASICs and secure radio transceivers in tactical handheld radios.

IC Role / Device Role / Timing Role: 85505012A serves as a controlled-direction bus transceiver, using separate OE pins to isolate transmit/receive paths and eliminate timing skew between cipher and RF subsystems.

Use Value: The 12 ns typical tpd and ±6 mA drive guarantee deterministic latency and signal integrity across encrypted data bursts, meeting STANAG 4285 timing compliance.

Spacecraft Onboard Computer Backplane

Nuclear Power Plant Safety PLC I/O Module

Use Scenario: Driving parallel address buses across multi-board backplanes in satellite onboard computers where radiation tolerance and zero failure rate are mandatory.

IC Role / Device Role / Timing Role: 85505012A functions as a radiation-tolerant address demultiplexer, leveraging its hermetic LCCC package and 3-state outputs to prevent single-event latch-up during solar particle events.

Use Value: Its qualified MIL-PRF-38535 Class B status and −65°C to +150°C storage range support 15+ year orbital missions without derating or redundancy overhead.

Use Scenario: Buffering critical trip-signal lines between redundant safety processors and analog I/O cards in nuclear reactor protection systems.

IC Role / Device Role / Timing Role: 85505012A provides fail-safe 3-state isolation between processor banks, ensuring no spurious output activation during processor reset or diagnostic self-test sequences.

Use Value: The 80 µA max ICC and ±10 µA max IOZ guarantee minimal leakage-induced false trips, satisfying IEC 61508 SIL-3 hardware fault tolerance requirements.

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal inverting 3-state buffer applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SNJ54HCT240FK	Identical die, same LCCC-FK package, identical electrical specs and MIL-PRF-38535 Class B qualification.	No functional or application difference - direct manufacturer-equivalent part number with identical marking and traceability.	Select SNJ54HCT240FK only if procurement documentation explicitly requires TI's standard military part numbering convention.
8550501RA	Same functionality and temperature range, but packaged in CDIP-J (ceramic dual in-line) instead of LCCC-FK; higher θJA (69°C/W vs. N/A for FK), larger footprint.	Suitable for through-hole prototyping or legacy board upgrades where LCCC rework is impractical, but not for high-density or vibration-prone deployments.	Choose 8550501RA only when mechanical compatibility with existing CDIP sockets or manual assembly constraints outweigh LCCC's hermetic and thermal advantages.

Compared with 85505012A, SNJ54HCT240FK offers identical performance and qualification with seamless interchangeability, while 8550501RA trades hermetic sealing and board-area efficiency for through-hole assembly flexibility - making 85505012A the optimal choice for new high-reliability surface-mount designs.

Availability

85505012A is available at Aetrix Electronics and suitable for avionics data bus interface, secure military communication controller, spacecraft onboard computer backplane, and nuclear power plant safety PLC I/O module applications requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for 85505012A 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and high-reliability logic solutions with over 50 years of aerospace and defense component experience.

The 85505012A belongs to TI's military HCT logic family, engineered specifically for high-integrity memory addressing, clock distribution, and bus driving in systems where extended temperature operation and MIL-qualified reliability are non-negotiable.

FAQ

What is the operating temperature range specified for the 85505012A?

The 85505012A is rated for operation from −55°C to +125°C, fully compliant with MIL-PRF-38535 Class B environmental screening requirements. This range is validated across all electrical parameters including propagation delay, output drive, and quiescent current - making it suitable for deployment in jet engines, space vehicles, and nuclear facility instrumentation where ambient extremes are routine. The 85505012A maintains specification compliance without derating across this full span.

Does the 85505012A support TTL-level input signals?

Yes, the 85505012A features TTL-voltage compatible inputs with VIH(min) = 2.0 V and VIL(max) = 0.8 V at VCC = 4.5 V to 5.5 V, allowing direct connection to legacy TTL outputs without level-shifting circuitry. Input current remains below 1 µA max, minimizing loading on upstream drivers. This compatibility is confirmed in the "Recommended Operating Conditions" and "Electrical Characteristics" tables of the official TI datasheet SCLS174E.

What package type is used for the 85505012A?

The 85505012A is supplied in a 20-terminal LCCC (Leadless Chip Carrier) package with FK outline - a ceramic hermetically sealed surface-mount package featuring J-leads and a center ground/power pad. Its dimensions, soldering profile, and thermal characteristics align with JEDEC MS-013 standards. This package provides superior moisture resistance, thermal stability, and mechanical robustness compared to plastic alternatives - essential for aerospace and defense applications.

How does the 3-state output control work on the 85505012A?

The 85505012A implements two independent active-low 3-state enables: 1OE controls outputs Y1–Y4, and 2OE controls Y1–Y4. When an OE pin is low, the corresponding four outputs invert their respective A-inputs; when high, those outputs enter high-impedance state with ±10 µA max leakage. This architecture allows precise time-gated bus sharing - for example, enabling one buffer bank during read cycles and the other during write cycles - without external arbitration logic.

Is the 85505012A pin-compatible with commercial-grade SN74HCT240 variants?

No - while the 85505012A shares identical logic functionality and pin assignment with SN74HCT240 devices, its LCCC-FK package has different mechanical dimensions, lead geometry, and thermal pad configuration than SOIC-DW, PDIP-N, or TSSOP-PW packages. Board layout, stencil design, and reflow profile must be specifically validated for the FK outline. Electrical pinout matches, but physical mounting and thermal management are not interchangeable.

85505012A Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: *

Package/Case:: -

Packaging:: Bulk

Product Status:: Active

Logic Type:: -

Number of Elements:: -

Number of Bits per Element:: -

Input Type:: -

Output Type:: -

Current - Output High, Low:: -

Voltage - Supply:: -

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: -

Supplier Device Package:: -

85505012A FAQ

1.How can I place an order for 85505012A through Aetrix?

Please submit a Request for Quotation (RFQ) for 85505012A 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 85505012A reliable?

The price and inventory of 85505012A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 85505012A is usually 5 days.

3.What payment methods are accepted for 85505012A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 85505012A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 85505012A?

85505012A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 85505012A 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 85505012A?

For technical support, including 85505012A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 85505012A requirements.

6.How does Aetrix verify that 85505012A is sourced from the original manufacturer or authorized distributors?

All 85505012A 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 85505012A meets industry standards.

7.What is the process for return or replacement of 85505012A?

All 85505012A units undergo pre-shipment inspection (PSI). If there is an issue with 85505012A, 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 85505012A part is unused and in its original packaging.

Return procedure for 85505012A:

1.Submit a request within 90 days.

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

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