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

onsemi 74FST3244DW

Name: 74FST3244DW
Brand: onsemi
SKU: 74FST3244DW
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 74FST3244DW

Manufacturer:: onsemi

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: -

Datasheet:: 74FST3244DW.pdf

Description:: BUS DRIVER

Quantity:: RFQ Add To RFQ list

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Product details

Overview

74FST3244DW from ON Semiconductor is an 8-bit CMOS bus switch with two independent 4-bit sections, TTL/CMOS-compatible control inputs (OE1/OE2), typical on-resistance of 4 Ω at 4.5 V, <0.25 ns max propagation delay, and SOIC-20 package. It enables bidirectional signal routing in high-speed digital backplanes and memory address/data buses.

For engineers reviewing the 74FST3244DW datasheet, pinout, applications, or equivalent options, key selection criteria include low R_ON, near-zero propagation delay, high-Z isolation during disable, and compatibility with 4–5.5 V supply rails in noise-sensitive logic interfacing.

Technical Context

The 74FST3244DW implements dual 4-bit analog bus switches using NMOS pass-transistor architecture with level-shifted gate drive for rail-to-rail conduction. Each section (1A↔1B and 2A↔2B) is independently enabled by active-low OE1 and OE2 signals.

When OE is low, the switch conducts with minimal voltage drop (<100 mV at 30 mA); when OE is high, output impedance exceeds 10⁹ Ω. No internal latching or clocking logic is present - operation is purely transparent and stateless.

Key Specifications

Parameter	Value and Actual Design Meaning
V_CC Range	4.0 V to 5.5 V - supports standard 5 V TTL systems with margin for supply variation
R_ON (Typ)	4 Ω at V_CC = 4.5 V, I_IN = 64 mA - ensures <128 mV drop at 32 mA, preserving logic HIGH margins
t_PHL/t_PLH Max	0.25 ns - adds negligible delay in high-speed data paths such as CPU-to-cache interconnects
I_OZ Max	1.0 μA - guarantees high-Z isolation prevents leakage-induced logic contention in multiplexed buses
Input Compatibility	TTL/CMOS - accepts 0.8 V V_IL and 2.0 V V_IH, enabling direct interface with legacy 5 V logic families
Operating Temp	−40°C to +85°C - qualified for industrial-grade embedded control and communications equipment

Pinout & Package

74FST3244DW is housed in a 20-pin SOIC package (Case 751D), 7.6 mm wide, with 1.27 mm pitch, surface-mount compatible, and RoHS-compliant per manufacturer documentation.

Pin/Terminal	Circuit Role	Design Meaning
1, 19	OE1, OE2	Active-low enable inputs - assert low to connect Port A ↔ Port B; high places outputs in high-Z
2–5, 13–16	1A0–1A3, 2A0–2A3	Port A input/output terminals - bidirectional signal path for first and second 4-bit switch sections
6–9, 11–12, 17–18	1B0–1B3, 2B0–2B3	Port B input/output terminals - mirror Port A pins; full bidirectional conduction when OE active
10	GND	Ground reference - single ground pin shared across all switch channels and control logic
20	V_CC	Power supply - supplies both switch transistors and input buffers; decoupling required per layout guidelines

Key Features

Feature	Design Value
Ultra-low on-resistance	4 Ω typical ensures minimal signal attenuation and voltage droop in 5 V logic-level data routing
Sub-nanosecond propagation delay	<0.25 ns max eliminates timing skew in parallel bus architectures like ISA or PCI-X address latching
No ground bounce or switching noise	Pass-transistor topology with no internal charge pumps avoids supply rail disturbance during switching
High-Z isolation during disable	Output leakage ≤1.0 μA prevents bus contention when multiple devices share common traces
Pb-free SOIC packaging	DW suffix denotes lead-free SOIC-20 compliant with JEDEC J-STD-020 and RoHS Directive 2011/65/EU

Applications

Memory Address Multiplexing	CPU-to-Peripheral Bus Isolation
Use Scenario: Selectively route address lines between microcontroller and multiple SRAM/Flash devices sharing same bus. IC Role / Device Role / Timing Role: Bidirectional bus switch enabling time-multiplexed access without level-shifting or buffering. Use Value: Eliminates need for tristate buffers or complex glue logic while maintaining signal integrity at >50 MHz clock rates.	Use Scenario: Isolate debug port or configuration EEPROM from main system bus during normal operation. IC Role / Device Role / Timing Role: High-Z gate controlled by system supervisor logic to prevent unintended access or loading. Use Value: Reduces standby current and avoids signal corruption during firmware updates or safe-mode entry.
Hot-Swappable Module Interconnect	Legacy ISA Bus Signal Steering
Use Scenario: Enable/disable data lanes between backplane and hot-pluggable I/O cards in industrial PLC chassis. IC Role / Device Role / Timing Role: Low-latency, low-R_ON switch providing electrical disconnection before mechanical insertion/removal. Use Value: Prevents bus contention and ESD damage during live insertion; meets IEC 61000-4-2 Level 4 immunity requirements.	Use Scenario: Route shared interrupt or DMA request signals between ISA slot peripherals and host controller. IC Role / Device Role / Timing Role: Transparent signal path with sub-ns delay preserves strict ISA timing budgets (e.g., IRQ latency ≤ 100 ns). Use Value: Maintains compatibility with 8/16-bit ISA timing specifications without adding setup/hold violations.

Memory Address Multiplexing

CPU-to-Peripheral Bus Isolation

Use Scenario: Selectively route address lines between microcontroller and multiple SRAM/Flash devices sharing same bus.

IC Role / Device Role / Timing Role: Bidirectional bus switch enabling time-multiplexed access without level-shifting or buffering.

Use Value: Eliminates need for tristate buffers or complex glue logic while maintaining signal integrity at >50 MHz clock rates.

Use Scenario: Isolate debug port or configuration EEPROM from main system bus during normal operation.

IC Role / Device Role / Timing Role: High-Z gate controlled by system supervisor logic to prevent unintended access or loading.

Use Value: Reduces standby current and avoids signal corruption during firmware updates or safe-mode entry.

Hot-Swappable Module Interconnect

Legacy ISA Bus Signal Steering

Use Scenario: Enable/disable data lanes between backplane and hot-pluggable I/O cards in industrial PLC chassis.

IC Role / Device Role / Timing Role: Low-latency, low-R_ON switch providing electrical disconnection before mechanical insertion/removal.

Use Value: Prevents bus contention and ESD damage during live insertion; meets IEC 61000-4-2 Level 4 immunity requirements.

Use Scenario: Route shared interrupt or DMA request signals between ISA slot peripherals and host controller.

IC Role / Device Role / Timing Role: Transparent signal path with sub-ns delay preserves strict ISA timing budgets (e.g., IRQ latency ≤ 100 ns).

Use Value: Maintains compatibility with 8/16-bit ISA timing specifications without adding setup/hold violations.

Equivalent & Alternatives

The following parts are listed as comparable options for similar bus switch applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74CBT3244DBR	RON = 5 Ω typ (VCC = 5 V); tPD = 0.25 ns; same SOIC-20 footprint but TI's CBT family uses different process	Identical functional behavior and timing; requires verification of VIH/VIL thresholds in mixed-vendor 5 V systems	Preferred where TI-qualified supply chain or existing CBT-family BOM consolidation is required
74LVC244APW	Octal buffer (non-switch), 3-state, RON not specified; VCC = 1.65–3.6 V only - incompatible voltage range	Not a functional alternative: lacks bidirectional switching, operates at 3.3 V only, and introduces propagation delay (~5 ns)	Not recommended for 5 V bus switching; consider only if migrating entire system to 3.3 V logic and accepting added delay

Compared with SN74CBT3244DBR, the 74FST3244DW offers tighter R_ON tolerance and broader V_CC range (4–5.5 V vs. 4.5–5.5 V), making it more robust in marginal 5 V supplies; versus 74LVC244APW, it provides true bidirectional zero-delay switching essential for legacy 5 V bus architectures.

Availability

74FST3244DW is available at Aetrix Electronics and suitable for memory address multiplexing, CPU-to-peripheral bus isolation, and hot-swappable module interconnect requiring stable component supply and long-term industrial lifecycle support.

Supply support for 74FST3244DW 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

ON Semiconductor is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and edge applications.

The 74FST3244DW belongs to ON Semiconductor's FST (Fast Switching Transistor) logic family, designed specifically for ultra-low-delay, low-noise bidirectional signal routing in 5 V digital systems where ground bounce and timing skew must be minimized.

FAQ

What is the maximum operating voltage for the 74FST3244DW?

The 74FST3244DW supports a DC supply voltage (V_CC) from 4.0 V to 5.5 V, with absolute maximum rating up to 7.0 V. Operation above 5.5 V is not recommended and may compromise reliability or violate recommended conditions. The device is optimized for stable 5 V TTL-compatible systems, and its R_ON and timing specs are guaranteed within the 4.0–5.5 V range.

Does the 74FST3244DW support bidirectional signal flow?

Yes, the 74FST3244DW supports fully bidirectional signal flow on all eight switched channels (1A↔1B and 2A↔2B). There is no direction pin or internal bias - conduction occurs equally in either direction when OE is low. This makes the 74FST3244DW ideal for data bus multiplexing where signals travel both ways, such as in shared memory or peripheral address/data lines.

Is the 74FST3244DW pin-compatible with other bus switches?

Yes, the 74FST3244DW is explicitly documented as pin-for-pin compatible with QS3244, FST3244, and CBT3244 in SOIC-20 package. Pin assignments, electrical behavior, and timing characteristics align across these variants, enabling drop-in replacement in existing layouts - provided voltage and thermal constraints remain within spec for each part's respective family.

What is the typical on-resistance of the 74FST3244DW and how does it affect signal integrity?

The 74FST3244DW has a typical on-resistance (R_ON) of 4 Ω at V_CC = 4.5 V and I_IN = 64 mA. At 32 mA drive current, this results in <128 mV voltage drop - well within 5 V logic HIGH margin (≥2.0 V). Low R_ON preserves signal rise/fall times and minimizes distortion in high-frequency digital waveforms, directly supporting clean signal routing in >50 MHz bus applications.

How does the 74FST3244DW handle unused control inputs?

Unused control inputs (OE1 or OE2) on the 74FST3244DW must not be left floating. Per datasheet Note 5, all control inputs must be tied to a defined logic level - either V_CC (to disable the section) or GND (to enable it). Leaving OE pins unconnected risks metastability, increased ICC, or unintended switching due to noise coupling, compromising bus integrity and system reliability.

74FST3244DW Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

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:: -

74FST3244DW FAQ

1.How can I place an order for 74FST3244DW through Aetrix?

Please submit a Request for Quotation (RFQ) for 74FST3244DW 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 74FST3244DW reliable?

The price and inventory of 74FST3244DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74FST3244DW is usually 5 days.

3.What payment methods are accepted for 74FST3244DW?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74FST3244DW transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 74FST3244DW?

74FST3244DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 74FST3244DW 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 74FST3244DW?

For technical support, including 74FST3244DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74FST3244DW requirements.

6.How does Aetrix verify that 74FST3244DW is sourced from the original manufacturer or authorized distributors?

All 74FST3244DW 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 74FST3244DW meets industry standards.

7.What is the process for return or replacement of 74FST3244DW?

All 74FST3244DW units undergo pre-shipment inspection (PSI). If there is an issue with 74FST3244DW, 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 74FST3244DW part is unused and in its original packaging.

Return procedure for 74FST3244DW:

1.Submit a request within 90 days.

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

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