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onsemi 74VHCT240ASJX
- Part No.:
- 74VHCT240ASJX
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
74VHCT240ASJX.pdf
- Description:
- IC BUFFER INVERT 5.5V 20SOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,577
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Product details
Overview
74VHCT240ASJX from onsemi is an octal inverting 3-STATE buffer/line driver with dual active-low output enables, designed for memory address driving, clock distribution, and bus-oriented transceiver applications. It operates at 4.5–5.5 V, delivers 3.6 ns typical propagation delay, supports 5 V ↔ 3 V level translation, and features ±25 mA output drive per pin.
For engineers reviewing the 74VHCT240ASJX datasheet, pinout, applications, or equivalent options, key selection criteria include its dual OE control logic, high-speed CMOS compatibility with TTL levels, input/output overvoltage tolerance up to 5.5 V, and TSSOP-20 packaging for space-constrained PCB layouts.
Technical Context
The 74VHCT240ASJX implements eight independent inverting buffers, each with output enable controlled by OE1 (pins 1,19) and OE2 (pins 2,18). Its silicon gate CMOS process achieves TTL-compatible speed while maintaining low static power - ICC ≤ 4 µA max at 25°C. Input and output protection circuits allow safe operation across 0–5.5 V regardless of VCC state.
It supports mixed-voltage interfacing: inputs tolerate 0–5.5 V even when VCC = 0 V (power-down mode), and outputs drive 3 V systems from a 5 V supply. The device meets JEDEC MO-153 mechanical standards and is Pb-free, rated MSL Level 1.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - ensures stable operation in standard 5 V digital systems with ±10% rail tolerance |
| tPD (Typ) | 3.6 ns at VCC = 5 V, CL = 15 pF - enables high-frequency bus buffering up to ~100 MHz system timing |
| IOH/IOL | ±8 mA - sufficient to drive multiple CMOS/TTL loads or terminate short traces without external buffers |
| VIH/VIL | 2.0 V / 0.8 V - compatible with TTL input thresholds and robust against noise margins in industrial environments |
| IOZ (Max) | ±2.5 µA at TA = −40°C to +85°C - guarantees minimal leakage in 3-STATE mode during system sleep or hot-swap |
| ESD Rating | 2000 V HBM - provides baseline ESD resilience for handling and board-level integration without special precautions |
Pinout & Package
TSSOP-20 package (Case 948AQ), 4.4 mm × 6.5 mm footprint, 0.65 mm pitch, JEDEC MO-153 compliant, lead-free.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | OE1 | Active-low enable for outputs O0–O3 (pins 12,14,16,18); both must be LOW for driver activation |
| 2, 18 | OE2 | Active-low enable for outputs O4–O7 (pins 3,5,7,9); independent control from OE1 |
| 3,5,7,9 | O4,O5,O6,O7 | Inverted 3-STATE outputs - HIGH/LOW or Hi-Z depending on OE2 and input state |
| 12,14,16,18 | O0,O1,O2,O3 | Inverted 3-STATE outputs - HIGH/LOW or Hi-Z depending on OE1 and input state |
| 4,6,8,10 | I4,I5,I6,I7 | Inputs driving O4–O7 - inverted logic relationship maintained in active state |
| 11,13,15,17 | I0,I1,I2,I3 | Inputs driving O0–O3 - inverted logic relationship maintained in active state |
| 20 | VCC | Positive supply (4.5–5.5 V) - powers all internal logic and output stages |
| 10 | GND | Ground reference - shared return path for inputs, outputs, and supply current |
Key Features
| Feature | Design Value |
|---|---|
| Input/Output Overvoltage Tolerance | Supports 0–5.5 V on I/O pins regardless of VCC state - enables safe interfacing between powered/unpowered subsystems |
| Dual Independent Output Enables | OE1 and OE2 allow selective activation of two 4-bit groups - reduces bus contention and simplifies timing in multi-bank memory systems |
| CMOS-Level Power Efficiency | ICC ≤ 4 µA max at 25°C - minimizes standby current in battery-backed or low-power hold modes |
| Pb-Free & MSL Level 1 | Complies with RoHS and JEDEC J-STD-020 - supports standard reflow profiles without moisture sensitivity concerns |
Applications
| Memory Address Buffering | Microcontroller Bus Expansion |
|---|---|
Use Scenario: Driving address lines from a microcontroller to multiple SRAM or flash devices sharing a common data bus. IC Role / Device Role / Timing Role: Inverting 3-STATE buffer isolating address signals and preventing contention during chip select transitions. Use Value: Dual OE control allows staggered enable timing across memory banks, reducing simultaneous switching noise and improving signal integrity. | Use Scenario: Expanding GPIO count of an MCU by adding peripheral control lines via parallel bus interface. IC Role / Device Role / Timing Role: Level-shifting and fan-out buffer for MCU port pins driving LEDs, relays, or sensor enable lines. Use Value: 5 V tolerant inputs accept direct connection to 3.3 V MCU outputs; ±8 mA drive supports direct LED sinking without external transistors. |
| Clock Distribution Network | Mixed-Voltage System Interface |
Use Scenario: Distributing a system clock to multiple synchronous peripherals with matched trace lengths. IC Role / Device Role / Timing Role: Low-skew inverting buffer (tOSLH/tOSHL ≤ 1.0 ns) ensuring deterministic edge alignment across destinations. Use Value: Sub-ns skew and 3.6 ns tPD support jitter-critical clock trees where phase consistency matters more than polarity. | Use Scenario: Interfacing a 5 V FPGA I/O bank to a 3 V ADC or DAC in a mixed-signal acquisition module. IC Role / Device Role / Timing Role: Bidirectional voltage translator enabling safe communication without external level shifters. Use Value: Input overvoltage tolerance eliminates need for series resistors or clamps when connecting to higher-voltage sources. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74HCT240N,112 (Nexperia) | Same pinout and logic function; slightly higher ICC (20 µA typ) and slower tPD (8 ns typ at 5 V) | Less suitable for high-speed clock distribution but adequate for general-purpose address buffering | Select when cost sensitivity outweighs speed requirements and legacy DIP-20 footprint is acceptable |
| SN74VHCT240PW (Texas Instruments) | Identical electrical specs and TSSOP-20 package; different marking and tape/reel packaging | No functional difference - drop-in replacement verified in TI's datasheet SN74VHCT240 | Choose for supply chain diversification while maintaining identical performance and layout compatibility |
Compared with 74VHCT240ASJX, the Nexperia 74HCT240N trades speed for broader legacy availability, while the TI SN74VHCT240PW offers identical timing and drive strength with alternate sourcing - both preserve dual-OE control and 5 V tolerance but differ in thermal resistance and long-term obsolescence risk.
Availability
74VHCT240ASJX is available at Aetrix Electronics and suitable for memory address buffering, microcontroller bus expansion, and clock distribution requiring stable component supply, RoHS compliance, and TSSOP-20 surface-mount compatibility.
Supply support for 74VHCT240ASJX 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The VHCT logic family targets high-speed, low-power 5 V digital interfacing - specifically engineered for TTL-compatible operation with CMOS efficiency in memory, bus, and clock subsystems.
FAQ
What is the maximum operating temperature range for the 74VHCT240ASJX?
The 74VHCT240ASJX is rated for continuous operation from −40°C to +85°C. This industrial temperature range is validated across all DC and AC electrical specifications in the onsemi datasheet, including propagation delay, output drive, and 3-STATE leakage. Thermal derating is not required within this span, and the device maintains full functionality at both extremes when supplied with 4.5–5.5 V.
Does the 74VHCT240ASJX support 3.3 V input logic levels when powered at 5 V?
Yes, the 74VHCT240ASJX accepts 3.3 V logic inputs reliably at VCC = 5 V. Its VIH threshold is guaranteed ≥2.0 V and VIL ≤0.8 V across temperature, providing >1.3 V noise margin for 3.3 V HIGH signals and >2.5 V margin for LOW. No external pull-ups or level translators are needed - the device is explicitly designed for 5 V ↔ 3 V system interfacing.
Can unused inputs on the 74VHCT240ASJX be left floating?
No, unused inputs on the 74VHCT240ASJX must be tied to a valid logic level - either VCC or GND - as specified in the datasheet's Recommended Operating Conditions. Floating inputs may cause increased ICC, erratic output states, or excessive power consumption due to undefined internal node voltages. This requirement applies to all eight inputs (I0–I7) and both OE pins (OE1, OE2).
What is the 3-STATE output disable time for the 74VHCT240ASJX?
The 74VHCT240ASJX has a maximum 3-STATE output disable time (tPHZ/tPLZ) of 13.0 ns at VCC = 5.0 V ±0.5 V and CL = 50 pF, measured from OE transition to output reaching valid Hi-Z state. This parameter ensures rapid bus release during dynamic enable/disable cycles, critical for avoiding contention in multi-driver systems like shared memory buses.
Is the 74VHCT240ASJX pin-compatible with older 74LS240 devices?
No, the 74VHCT240ASJX is not pin-compatible with 74LS240. While both are octal inverting buffers with 3-STATE outputs, the 74LS240 uses a different pinout (e.g., OE on pins 1 and 15 vs. 1/19 and 2/18 on 74VHCT240ASJX) and lacks input overvoltage tolerance. The 74VHCT240ASJX is pin- and function-compatible only with 74HCT240, not bipolar TTL families.
74VHCT240ASJX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74VHCT
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Logic Type:
- Buffer, Inverting
- Number of Elements:
- 2
- Number of Bits per Element:
- 4
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 8mA, 8mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOP
74VHCT240ASJX FAQ
1.How can I place an order for 74VHCT240ASJX through Aetrix?
Please submit a Request for Quotation (RFQ) for 74VHCT240ASJX 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 74VHCT240ASJX reliable?
The price and inventory of 74VHCT240ASJX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74VHCT240ASJX is usually 5 days.
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4.How is shipping managed for 74VHCT240ASJX?
74VHCT240ASJX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74VHCT240ASJX 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 74VHCT240ASJX?
For technical support, including 74VHCT240ASJX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74VHCT240ASJX requirements.
6.How does Aetrix verify that 74VHCT240ASJX is sourced from the original manufacturer or authorized distributors?
All 74VHCT240ASJX 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 74VHCT240ASJX meets industry standards.
7.What is the process for return or replacement of 74VHCT240ASJX?
All 74VHCT240ASJX units undergo pre-shipment inspection (PSI). If there is an issue with 74VHCT240ASJX, 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 74VHCT240ASJX part is unused and in its original packaging.
Return procedure for 74VHCT240ASJX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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