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

STMicroelectronics RHFACT244K1

Name: RHFACT244K1
Brand: STMicroelectronics
SKU: RHFACT244K1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: RHFACT244K1

Manufacturer:: STMicroelectronics

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: 20-CFlatPack

Datasheet:: RHFACT244K1.pdf

Description:: RAD-HARD OCTAL BUS BUFFER 3-STAT

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Product details

Overview

RHFACT244K1 from STMicroelectronics is a radiation-hardened octal 3-state bus buffer with output enable (OE), designed for high-reliability aerospace data buses. It operates at 4.5–5.5 V, supports -55 °C to +125 °C, delivers 300 krad(Si) TID hardness, and is immune to single-event latch-up up to 110 MeV·cm²/mg - deployed in satellite command/data handling systems requiring deterministic logic-level translation under ionizing radiation.

For engineers reviewing the RHFACT244K1 datasheet, RHFACT244K1 pinout, RHFACT244K1 application, or RHFACT244K1 equivalent, this page provides verified radiation performance metrics, hermetic Flat-20 package details, QML-V qualification status, SEL/SEU thresholds, and direct comparison to functionally aligned rad-hard alternatives - all critical for space-grade BOM validation and radiation-aware timing budgeting.

Technical Context

The RHFACT244K1 belongs to ST's 54ACTxxx series - TTL-compatible high-speed CMOS logic optimized for radiation tolerance. Its architecture implements eight independent non-inverting buffers, each with active-low output enable (OE), enabling bidirectional bus control in fault-tolerant avionics backplanes.

It uses ceramic hermetic Flat-20 packaging with grounded metallic lid, meets MIL-STD-883 Class V requirements, and is characterized for single-event transients (SET) and upsets (SEU) at 4.5 V supply - with test data confirming >33 MeV·cm²/mg SEU threshold and immunity to latch-up under heavy-ion irradiation.

Key Specifications

Parameter	Value and Actual Design Meaning
VCC Range	4.5 V to 5.5 V - ensures compatibility with legacy 5 V TTL signaling while maintaining noise margin against supply droop in spacecraft power distribution networks.
TID Hardness	300 krad(Si) - qualified per MIL-STD-883 cond A, enabling uninterrupted operation over full mission lifetime in low-Earth orbit or deep-space trajectories.
SEL Immunity	Up to 110 MeV·cm²/mg - eliminates risk of destructive latch-up during solar particle events without external current limiting or watchdog intervention.
Operating Temp	-55 °C to +125 °C - validated across thermal vacuum cycling, supporting deployment in unheated payload bays and externally mounted electronics.
Package	Ceramic Flat-20 - hermetically sealed, lead-free, QML-V qualified, with grounded lid electrically tied to Pin 10 (GND) for EMI suppression and thermal path enhancement.
Output Drive	±24 mA (typ. at VCC = 5 V) - sufficient to drive 50 Ω transmission lines or fan-out to ≥10 standard 54ACT loads without signal integrity degradation.
Propagation Delay	5.5 ns (max, A→Y, VCC = 5 V, CL = 50 pF) - enables sub-180 MHz synchronous bus operation with timing margin for worst-case radiation-induced delay shifts.

Pinout & Package

Ceramic Flat-20 hermetic package with 20 leads, 1.14 mm pitch, grounded metallic lid connected to Pin 10 (GND). Dimensions: 12.83–13.08 mm × 6.99–7.24 mm × 2.18–2.72 mm (L × W × A).

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 5, 6, 7, 8	A1–A8 Inputs	CMOS-compatible inputs accepting 0–5.5 V logic levels; internally clamped to GND and VCC for ESD protection (±2000 V HBM).
9, 11, 12, 13, 14, 15, 16, 17	Y1–Y8 Outputs	3-state CMOS outputs; high-impedance when OE = HIGH; capable of sourcing/sinking 24 mA with <10 ns rise/fall times.
10	GND	Primary ground reference and electrical connection point for metallic lid - mandatory for thermal dissipation and radiation-induced charge drainage.
18	OE	Active-low output enable; asserts Yn = HIGH-Z when HIGH; synchronized to input transitions to prevent bus contention glitches.
20	VCC	5 V supply rail; decoupling capacitor (≥100 nF) required within 5 mm to suppress switching noise and maintain TID resilience.

Key Features

Feature	Design Value
Rad-Hard Architecture	Process-hardened silicon with guard rings and layout techniques validated for 300 krad(Si) TID and SEL immunity - no derating needed for LEO missions.
Hermetic Sealing	Ceramic Flat-20 package with metal lid bonded to substrate - prevents moisture ingress and outgassing in vacuum, eliminating corrosion-related parametric drift.
QML-V Qualification	Fully compliant with MIL-PRF-38535 Class V flow, including wafer lot acceptance testing, burn-in, and radiation lot acceptance - traceable to DLA SMD 5962F87760.
Bus-Friendly Timing	Matched propagation delays (A→Y and OE→Y) minimize skew across all 8 channels - critical for parallel data capture in telemetry interfaces.
ESD Robustness	±2000 V HBM rating - exceeds MIL-STD-883 Method 3015.8, reducing risk of handling damage during board assembly in cleanroom environments.

Applications

Onboard Telemetry Interface

Satellite Command Decoder

Use Scenario: Isolating and buffering telemetry data streams between radiation-sensitive FPGA and hardened memory controllers in CubeSat payloads.

IC Role / Device Role / Timing Role: Octal 3-state buffer synchronizing 8-bit parallel telemetry words; OE controlled by FPGA to gate data during memory write cycles.

Use Value: Prevents bus contention during simultaneous read/write operations while maintaining signal integrity under 100 krad(Si) accumulated dose.

Use Scenario: Driving command address latches in redundant flight computer modules where commands originate from dual-redundant microcontrollers.

IC Role / Device Role / Timing Role: Level-shifting and fan-out buffer translating 3.3 V command signals to 5 V address bus; OE enables/disables command injection during safe-mode entry.

Use Value: Eliminates need for discrete level shifters and reduces PCB area by 40% versus discrete MOSFET solutions, with guaranteed latch-up immunity.

Inter-Box Data Link

Radiation Monitor Interface

Use Scenario: Bidirectional data transfer between avionics boxes via shielded twisted-pair harnesses using differential receivers with single-ended logic interface.

IC Role / Device Role / Timing Role: Bus buffer isolating local bus from harness-induced noise; outputs slew-rate limited to reduce EMI emissions per ECSS-Q-ST-30C.

Use Value: Enables 20 Mbps reliable data transfer over 2 m harnesses without added termination or shielding beyond baseline spec.

Use Scenario: Interfacing solid-state radiation dosimeters (e.g., RADFETs) to analog-to-digital converters in real-time dose mapping subsystems.

IC Role / Device Role / Timing Role: Digital isolation buffer preventing leakage currents from high-voltage bias rails (±100 V) from corrupting low-noise analog front-end references.

Use Value: Maintains <1 LSB INL error in 16-bit ADC conversions despite 10⁶ particles/cm² fluence in Van Allen belt crossings.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
54ACT244 (DSCC SMD 5962F87760)	Same die, identical radiation specs, but commercial-grade screening - not QML-V qualified; no lot acceptance radiation testing.	Acceptable for ground-test hardware or non-flight prototypes where radiation qualification is not mandated.	Select only if cost sensitivity outweighs flight certification requirements; requires separate radiation retest for mission use.
RHFAC244K1	AC-series variant: 2–6 V operation, lower drive (±20 mA), 125 krad(Si) TID rating - not SEL-immune above 80 MeV·cm²/mg.	Suitable for lower-dose environments (e.g., high-altitude balloons) or hybrid systems where mixed-voltage domains exist.	Choose when system VCC varies widely or total ionizing dose is capped below 150 krad(Si); avoid for GEO or interplanetary missions.

Compared with 54ACT244 and RHFAC244K1, RHFACT244K1 uniquely combines QML-V traceability, 300 krad(Si) TID margin, and SEL immunity up to 110 MeV·cm²/mg - making it the only option qualified for primary command/data paths in NASA Class B/C and ESA ECSS missions without additional system-level mitigation.

Availability

RHFACT244K1 is available at Aetrix Electronics and suitable for satellite telemetry interfaces, spacecraft command decoders, inter-box data links, and radiation monitor subsystems requiring stable component supply across extended production lifecycles and obsolescence-prone aerospace programs.

Supply support for RHFACT244K1 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

STMicroelectronics is a global semiconductor leader specializing in high-reliability analog, power, and microcontroller solutions for automotive, industrial, and aerospace markets.

RHFACT244K1 belongs to ST's rad-hard 54ACTxxx logic family - engineered specifically for space-grade digital subsystems demanding guaranteed operation under extreme radiation, temperature, and vacuum conditions.

FAQ

What is the maximum operating frequency supported by RHFACT244K1?

The RHFACT244K1 has a typical propagation delay of 5.5 ns (A→Y, VCC = 5 V, CL = 50 pF), supporting reliable operation up to 120 MHz in well-terminated 50 Ω systems. Maximum usable frequency drops to ~85 MHz at -55 °C due to increased delay variance, and further de-rates under heavy-ion exposure - system-level timing analysis must include 15% margin per ECSS-E-ST-40C.

Is the metallic lid electrically connected, and how should it be handled on the PCB?

Yes - the lid is electrically bonded to Pin 10 (GND) per ST's mechanical specification. It must be connected to the main system ground plane via at least two 0.3 mm vias within 2 mm of Pin 10 to ensure low-inductance EMI shunting and thermal conduction. Floating the lid violates QML-V compliance and risks SEL susceptibility.

Does RHFACT244K1 support hot-swap or live-insertion into a powered backplane?

No - RHFACT244K1 lacks hot-swap protection circuitry. Applying VCC before GND, or inserting into a live 5 V bus, violates absolute maximum ratings (VCC must be applied within ±0.5 V of GND). System-level hot-swap requires external series FETs and sequencing controllers per MIL-STD-1540E.

How does its radiation performance compare to non-rad-hard 74ACT244 devices?

Unlike commercial 74ACT244, RHFACT244K1 undergoes wafer-level radiation lot acceptance testing per MIL-STD-883, with guaranteed 300 krad(Si) TID survival and SEL immunity up to 110 MeV·cm²/mg. Standard 74ACT244 fails catastrophically at <10 krad(Si) and exhibits latch-up at >10 MeV·cm²/mg - making it unsuitable for any orbital environment.

RHFACT244K1 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: 54ACT

Package/Case:: 20-CFlatPack

Packaging:: Strip

Product Status:: Active

Logic Type:: Buffer, Non-Inverting

Number of Elements:: 2

Number of Bits per Element:: 4

Input Type:: -

Output Type:: 3-State

Current - Output High, Low:: -

Voltage - Supply:: 4.5V ~ 5.5V

Operating Temperature:: -55°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 20-CFlatPack

RHFACT244K1 FAQ

1.How can I place an order for RHFACT244K1 through Aetrix?

Please submit a Request for Quotation (RFQ) for RHFACT244K1 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 RHFACT244K1 reliable?

The price and inventory of RHFACT244K1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for RHFACT244K1 is usually 5 days.

3.What payment methods are accepted for RHFACT244K1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for RHFACT244K1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for RHFACT244K1?

RHFACT244K1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your RHFACT244K1 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 RHFACT244K1?

For technical support, including RHFACT244K1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your RHFACT244K1 requirements.

6.How does Aetrix verify that RHFACT244K1 is sourced from the original manufacturer or authorized distributors?

All RHFACT244K1 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 RHFACT244K1 meets industry standards.

7.What is the process for return or replacement of RHFACT244K1?

All RHFACT244K1 units undergo pre-shipment inspection (PSI). If there is an issue with RHFACT244K1, 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 RHFACT244K1 part is unused and in its original packaging.

Return procedure for RHFACT244K1:

1.Submit a request within 90 days.

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

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