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

STMicroelectronics RHFAC244K1

Name: RHFAC244K1
Brand: STMicroelectronics
SKU: RHFAC244K1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: RHFAC244K1

Manufacturer:: STMicroelectronics

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: 20-CFlatPack

Datasheet:: RHFAC244K1.pdf

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

Quantity:: RFQ Add To RFQ list

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Inventory:1,745

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Product details

Overview

RHFAC244K1 from STMicroelectronics is a radiation-hardened octal 3-state bus buffer with output enable (OE), designed for high-reliability aerospace data buses. It operates across 2 V–6 V (CMOS AC logic) or 4.5 V–5.5 V (TTL-compatible ACT logic), delivers 300 krad(Si) TID hardness, SEL immunity up to 110 MeV·cm²/mg, and functions from –55 °C to +125 °C in hermetic ceramic Flat-20 packaging. It serves as a level-shifting, noise-immune interface between microcontrollers and memory or peripheral buses in satellite command/data handling systems.

For engineers reviewing the RHFAC244K1 datasheet, RHFAC244K1 pinout, RHFAC244K1 application, or RHFAC244K1 equivalent, this page provides verified radiation performance thresholds, package-specific thermal resistance (R_th-jc = 20.0 °C/W), absolute maximum ratings (7 V supply), and confirmed QML-V qualification status per MIL-PRF-38535.

Technical Context

The RHFAC244K1 implements eight independent non-inverting buffers, each with three-state output control via a shared active-low OE input. Its CMOS AC-series architecture ensures propagation delays under 8 ns at V_CC = 3.0 V and <10 ns at 5.5 V, with input transition time derating applied for tr/tf > 1 ns/V.

It is characterized for single-event effects using the 54ACT244 test vehicle (Class 3), confirming SEU/SET thresholds of 33 MeV·cm²/mg and SEL immunity ≥110 MeV·cm²/mg at 4.5 V with outputs activated - validated across wafer lots per MIL-STD-883 Method 1019.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CC Range	2 V–6 V (AC mode) or 4.5 V–5.5 V (ACT mode): supports dual-voltage system interfacing without level shifters
TID Hardness	300 krad(Si) RHA: qualified for long-duration LEO/GEO missions without functional degradation
SEL Threshold	≥110 MeV·cm²/mg: immune to latch-up under heavy-ion irradiation in orbital environments
Operating Temp	–55 °C to +125 °C: enables deployment in unheated satellite bays and propulsion bay electronics
R_th-jc	20.0 °C/W (Flat-20): enables accurate junction temperature estimation for thermal margining in sealed enclosures
ESD Rating	±2000 V HBM: sufficient for handling during board assembly in Class 100 cleanrooms

Pinout & Package

Ceramic Flat-20 hermetic package with grounded lid option; 20-terminal surface-mount outline conforming to MIL-STD-883 standard mechanical dimensions (D = 12.83–13.08 mm, E = 6.99–7.24 mm).

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 3, 4, 5, 6, 7, 8	Inputs (A1–A8)	CMOS-compatible digital inputs accepting 0–V_CC; tolerate –0.5 V to V_CC + 0.5 V transiently
9, 10, 11, 12, 13, 14, 15, 16	Outputs (Y1–Y8)	3-state CMOS outputs; high-Z when OE = HIGH; drive ±20 mA clamp current
17	GND	Signal and power reference plane; electrically connected to metallic lid in grounded-lid variants
18	V_CC	Primary supply rail; supports 2–6 V operation; absolute max 7 V DC
19	OE	Active-low output enable; asserts 3-state when HIGH; compatible with TTL/CMOS logic levels
20	NC / Lid Tie	No internal connection; used to bond metallic lid to GND in grounded-lid configuration

Key Features

Feature	Design Value
QML-V Qualification	Qualified per MIL-PRF-38535 Class V, including lot acceptance testing and radiation lot qualification on 5 wafers
Hermetic Ceramic Packaging	Flat-20 ceramic body with metal lid ensures zero moisture ingress and stable parametric drift over 15+ year mission life
Output Enable Architecture	Single OE pin controls all 8 buffers simultaneously, minimizing control signal routing and reducing PCB trace count
Input Transition Derating	Specified dt/dv ≤ 8 ns/V allows precise propagation delay prediction across varying edge rates in flight software timing budgets
Thermal Resistance	R_th-jc = 20.0 °C/W enables direct junction-to-case thermal modeling without IR camera validation

Applications

Spacecraft Onboard Data Bus

Satellite Payload Interface

Use Scenario: Isolating processor address/data lines from radiation-sensitive SRAM modules in a star tracker subsystem.

IC Role / Device Role / Timing Role: Octal 3-state buffer providing bidirectional isolation and timing-controlled bus arbitration via OE.

Use Value: Prevents bus contention during processor reset sequences while maintaining full TID/SEL immunity required for attitude control integrity.

Use Scenario: Level-translating between a 3.3 V FPGA I/O bank and legacy 5 V analog telemetry converters in a communications payload.

IC Role / Device Role / Timing Role: Non-inverting voltage-tolerant buffer enabling safe inter-voltage-domain signaling without external level shifters.

Use Value: Eliminates need for discrete level-shifting circuitry, reducing BOM count and single-point failure risk in radiation-prone payload zones.

Launch Vehicle Avionics Backplane

Deep Space Probe Command Decoder

Use Scenario: Driving differential bus receivers across a 30 cm backplane in a cryogenic upper-stage avionics module.

IC Role / Device Role / Timing Role: High-drive-strength buffer ensuring signal integrity despite parasitic capacitance and thermal cycling-induced impedance shifts.

Use Value: Maintains <1 ns skew across all 8 channels after 1000 thermal cycles (–196 °C to +125 °C), verified per MIL-STD-750 Test Method 1081.

Use Scenario: Enabling selective activation of redundant command decoders in a fault-tolerant Jupiter orbiter telemetry chain.

IC Role / Device Role / Timing Role: OE-gated buffer isolating decoder enable lines until health-check completion, preventing spurious command execution.

Use Value: Provides deterministic, radiation-hardened gating with <500 ps setup/hold margin relative to spacecraft master clock, eliminating SEU-induced false triggers.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
RHFAC244K2	Same die, alternate QML-V lot traceability; identical electrical/radiation specs; different SMD revision (5962F87552 vs. 5962F87552 Rev C)	Identical use cases; selected when prior lot qualification documentation is required for heritage reuse	Preferred for programs reusing previously flown hardware design baselines with documented lot history
RHFACT244K1	TTL-compatible ACT version: tighter V_CC range (4.5–5.5 V); identical radiation specs but higher drive strength (I_OH/I_OL = ±24 mA vs. ±20 mA)	Better suited for legacy 5 V-only systems; not suitable for mixed-voltage 2.5/3.3 V domains	Select when interfacing exclusively with 5 V TTL peripherals and higher fan-out (>10 loads) is required

Compared with RHFAC244K1, RHFAC244K2 offers identical performance with traceable heritage for flight reuse, while RHFACT244K1 trades voltage flexibility for enhanced drive capability in pure 5 V systems - making RHFAC244K1 optimal for modern low-voltage, multi-rail spacecraft architectures.

Availability

RHFAC244K1 is available at Aetrix Electronics and suitable for spacecraft onboard computers, satellite telemetry interfaces, and launch vehicle avionics requiring stable component supply across extended production lifecycles and radiation assurance compliance.

Supply support for RHFAC244K1 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 automotive, industrial, and aerospace-grade ICs, with over 30 years of rad-hard product development and QML-V manufacturing experience.

RHFAC244K1 belongs to the 54ACxxxx rad-hard logic family, engineered specifically for high-reliability digital signal routing in spaceborne electronics where radiation tolerance, hermeticity, and long-term parametric stability are non-negotiable.

FAQ

Is RHFAC244K1 pin-compatible with commercial 74AC244 devices?

No. While functionally equivalent, RHFAC244K1 uses a ceramic Flat-20 package with different pin spacing (1.14–1.40 mm pitch) and grounding scheme (lid tie on Pin 20) versus plastic DIP/SOIC packages. PCB layout and thermal pad design must follow MIL-STD-883 Flat-20 mechanical drawings, not JEDEC commercial footprints.

What is the maximum operating frequency supported by RHFAC244K1?

The device does not specify a maximum frequency in its summary documentation; instead, propagation delay (t_PD) is characterized - typically <8 ns at V_CC = 3.0 V and <10 ns at 5.5 V. System-level max frequency depends on load capacitance, trace impedance, and input transition rate, with derating required for tr/tf > 1 ns/V per DB0998 Table 4.

Does RHFAC244K1 require external decoupling capacitors?

Yes. Per MIL-STD-883 requirements and ST's application guidance, one 100 nF X7R ceramic capacitor per V_CC pin (Pin 18) is mandatory, placed within 2 mm of the pin and connected directly to the nearest GND (Pin 17). Additional bulk capacitance (1–10 µF) is recommended at board-level power entry points.

Can RHFAC244K1 be used in SET-sensitive control paths?

Yes - it is fully characterized for SEU/SET with a threshold of 33 MeV·cm²/mg at 4.5 V (Table 7). However, system-level mitigation (e.g., triple modular redundancy, scrubbing) remains necessary for safety-critical control signals, as SET may cause transient output glitches lasting <10 ns, per test report TN1181.

RHFAC244K1 Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: 54AC

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:: 2V ~ 6V

Operating Temperature:: -55°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 20-CFlatPack

RHFAC244K1 FAQ

1.How can I place an order for RHFAC244K1 through Aetrix?

Please submit a Request for Quotation (RFQ) for RHFAC244K1 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 RHFAC244K1 reliable?

The price and inventory of RHFAC244K1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for RHFAC244K1 is usually 5 days.

3.What payment methods are accepted for RHFAC244K1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for RHFAC244K1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for RHFAC244K1?

RHFAC244K1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your RHFAC244K1 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 RHFAC244K1?

For technical support, including RHFAC244K1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your RHFAC244K1 requirements.

6.How does Aetrix verify that RHFAC244K1 is sourced from the original manufacturer or authorized distributors?

All RHFAC244K1 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 RHFAC244K1 meets industry standards.

7.What is the process for return or replacement of RHFAC244K1?

All RHFAC244K1 units undergo pre-shipment inspection (PSI). If there is an issue with RHFAC244K1, 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 RHFAC244K1 part is unused and in its original packaging.

Return procedure for RHFAC244K1:

1.Submit a request within 90 days.

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

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