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onsemi 74VHCT240AMX
- Part No.:
- 74VHCT240AMX
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
74VHCT240AMX.pdf
- Description:
- IC BUFFER INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,552
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Product details
Overview
74VHCT240AMX from onsemi is an octal inverting 3-STATE buffer/line driver with two active-low output enables, designed for memory address driving, clock distribution, and bidirectional bus interfacing in mixed-voltage systems. 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 74VHCT240AMX datasheet, pinout, applications, or equivalent options, key selection criteria include 3-STATE timing (tPZL/tPLZ ≤ 13.5 ns), input/output overvoltage tolerance (−0.5 V to +6.5 V), low ICC (≤ 4 µA quiescent), and TSSOP20 package compatibility with space-constrained PCB layouts.
Technical Context
The 74VHCT240AMX implements dual independent 3-STATE enable logic (OE1/OE2) controlling eight inverting buffer channels (I0–I7 → O0–O7). Its silicon-gate CMOS process achieves TTL-compatible speed while maintaining CMOS power efficiency. Input and output protection circuits allow safe operation across supply mismatches - e.g., 5 V VCC with 3 V inputs or floating outputs during power-down.
It is functionally and pin-compatible with 74HCT240 but optimized for higher noise immunity and wider voltage tolerance. The device meets JEDEC MO-153 mechanical standards for TSSOP20 (4.4 mm × 6.5 mm) and supports industrial temperature range (−40°C to +85°C) with guaranteed AC performance at CL = 50 pF.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - ensures stable operation in standard 5 V logic rails with ±10% tolerance. |
| tPD (Typ) | 3.6 ns at VCC = 5 V, CL = 15 pF - enables high-speed address/data buffering in microcontroller and FPGA peripheral buses. |
| IOH/IOL | ±8 mA - sufficient to drive multiple CMOS/TTL loads without external buffers in point-to-point or lightly loaded bus applications. |
| VIH/VIL | 2.0 V / 0.8 V - compatible with both 5 V TTL and 3.3 V LVTTL logic thresholds for mixed-voltage interface design. |
| Input/Output Voltage Range | −0.5 V to +6.5 V - allows safe hot-plug, battery-backup, or mismatched supply scenarios without clamping diodes or external protection. |
| ICC (Max) | 4.0 µA at TA = 25°C - enables ultra-low static power in always-on control logic or standby-mode subsystems. |
| Package | TSSOP20 (Case 948AQ, 4.4 mm × 6.5 mm) - surface-mount footprint suitable for high-density PCBs with automated assembly. |
Pinout & Package
TSSOP20 package (JEDEC MO-153 compliant), 0.65 mm pitch, 20-terminal surface-mount outline with exposed pad not present. Dimensions: 4.4 mm × 6.5 mm × 1.2 mm height.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | OE1, OE2 | Active-low 3-STATE enables - both must be LOW to activate all eight outputs; independent control enables partial bus gating. |
| 2–9 | I0–I7 | Inverting input terminals - each drives corresponding output with polarity inversion; unused inputs must be tied to VCC or GND. |
| 11–18 | O0–O7 | Inverting 3-STATE outputs - enter high-impedance state when either OE1 or OE2 is HIGH; tolerate −0.5 V to +6.5 V in OFF-state. |
| 10 | GND | Ground reference - common return path for all signals and supply current; requires low-inductance connection for noise control. |
| 20 | VCC | Positive supply - powers internal logic and output drivers; decoupling capacitor (0.1 µF) required near pin for AC stability. |
Key Features
| Feature | Design Value |
|---|---|
| Overvoltage-tolerant I/O | Inputs and outputs withstand −0.5 V to +6.5 V regardless of VCC - eliminates need for external level shifters in 3 V/5 V mixed-signal interfaces. |
| Power-down protection | Input and output clamp circuits remain functional at VCC = 0 V - prevents latch-up and damage during hot insertion or brown-out conditions. |
| Low dynamic power | CPD = 19 pF - minimizes switching current (ICC(opr.) = CPD·VCC·fIN + ICC/8), critical for high-frequency clock distribution with low EMI. |
| Pb-free construction | RoHS-compliant TSSOP20 package - meets global environmental regulations without compromising thermal or mechanical reliability. |
| Timing skew control | tOSLH/tOSHL ≤ 1.0 ns (CL = 50 pF) - ensures simultaneous edge alignment across all eight outputs for synchronous bus timing integrity. |
Applications
| Memory Address Buffering | Industrial PLC Backplane Interface |
|---|---|
Use Scenario: Driving 16-bit address lines from a microcontroller to multiple SRAM/Flash devices on a shared bus. IC Role / Device Role / Timing Role: Inverting 3-STATE buffer with dual OE control isolates address segments during chip-select arbitration. Use Value: 3.6 ns tPD and <1 ns output skew ensure setup/hold timing margins are maintained across all address bits at 25 MHz bus rates. | Use Scenario: Interfacing 5 V field I/O modules with a 3.3 V programmable logic controller CPU board. IC Role / Device Role / Timing Role: Level-translating bus driver enabling bidirectional data exchange between mismatched voltage domains. Use Value: −0.5 V to +6.5 V I/O tolerance allows direct connection without external resistors or translators, reducing BOM count and layout area. |
| Embedded Clock Distribution | Battery-Backed Real-Time Clock Interface |
Use Scenario: Fan-out of a 5 V system clock to multiple peripherals (ADC, UART, GPIO expanders) requiring synchronized timing. IC Role / Device Role / Timing Role: Low-skew inverting buffer with 3-STATE capability enables dynamic clock gating per peripheral. Use Value: tPZL ≤ 13.5 ns and tPLZ ≤ 13.0 ns support precise enable/disable timing for power-aware clock management. | Use Scenario: Isolating RTC registers and backup RAM from main system power during sleep or brown-out events. IC Role / Device Role / Timing Role: 3-STATE bus isolator activated only during RTC read/write cycles to prevent leakage paths. Use Value: IOZ ≤ ±2.5 µA in OFF-state and power-down protection maintain RTC accuracy and battery life over >10-year deployments. |
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 |
|---|---|---|---|
| 74HCT240N,112 (Nexperia) | Same pinout and logic function; slightly higher ICC (20 µA max) and slower tPD (8 ns typ at 5 V). | Less suitable for ultra-low-power standby modes but widely available in DIP/SO packages for prototyping. | Select when legacy through-hole mounting or extended temperature validation is required. |
| SN74LVTH240PW (TI) | 3.3 V only (VCC = 2.7–3.6 V); LVCMOS-compatible VIH/VIL; faster tPD (2.8 ns typ) but no 5 V tolerant I/O. | Optimized for 3.3 V-only systems; cannot replace 74VHCT240AMX in 5 V or mixed-voltage designs. | Select only for new 3.3 V designs where 5 V tolerance is unnecessary and lower propagation delay is critical. |
Compared with 74HCT240N and SN74LVTH240PW, the 74VHCT240AMX uniquely balances 5 V operation, 5 V tolerant I/O, sub-4 ns speed, and µA-level quiescent current - making it the preferred choice for industrial mixed-voltage bus isolation where reliability and voltage flexibility are non-negotiable.
Availability
74VHCT240AMX is available at Aetrix Electronics and suitable for industrial automation controllers, embedded instrumentation systems, and battery-backed real-time clock modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for 74VHCT240AMX 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 specializing in energy-efficient, high-reliability components for automotive, industrial, cloud, and IoT applications.
The VHCT logic family, including the 74VHCT240AMX, was engineered for robust mixed-voltage interfacing in harsh industrial environments - emphasizing overvoltage protection, wide temperature operation, and low static power without sacrificing speed.
FAQ
What is the maximum operating temperature range for the 74VHCT240AMX?
The 74VHCT240AMX is rated for continuous operation from −40°C to +85°C. This industrial-grade temperature range is validated across all AC and DC electrical specifications in the official onsemi datasheet (Rev. 2, August 2024), ensuring reliable performance in factory automation, outdoor instrumentation, and motor control enclosures without derating.
Does the 74VHCT240AMX support 3.3 V logic inputs while powered at 5 V?
Yes, the 74VHCT240AMX accepts 3.3 V logic inputs at VCC = 5 V. Its VIH threshold is 2.0 V minimum and VIL is 0.8 V maximum across the full operating range, making it fully compatible with LVTTL and 3.3 V CMOS outputs. This capability is explicitly confirmed in the DC Electrical Characteristics table on page 3 of the onsemi datasheet.
Can the 74VHCT240AMX outputs safely float to 5.5 V when VCC = 0 V?
Yes, the 74VHCT240AMX outputs tolerate up to +6.5 V in the 3-STATE (high-impedance) mode and during power-off (VCC = 0 V), as specified in the Absolute Maximum Ratings table. This feature enables safe hot-swap and battery-backup operation without risk of latch-up or damage - a key differentiator versus standard HCT devices.
Is the 74VHCT240AMX pin-compatible with the 74VHCT240MTCX?
Yes, the 74VHCT240AMX and 74VHCT240MTCX share identical TSSOP20 pinout, logic function, and electrical specifications. The "MX" and "MTCX" suffixes both denote Pb-free TSSOP20 packaging per onsemi's ordering nomenclature - confirmed in the Ordering Information section (page 4) of the datasheet.
What is the typical power dissipation of the 74VHCT240AMX at 10 MHz operation?
At VCC = 5 V and fIN = 10 MHz with CL = 50 pF, the 74VHCT240AMX draws approximately 1.1 mA average supply current. This is calculated using CPD = 19 pF from the datasheet: ICC(opr.) = CPD·VCC·fIN + ICC/8 = (19 pF)(5 V)(10 MHz) + (4 µA)/8 ≈ 0.95 mA + 0.5 µA ≈ 1.1 mA - well within safe thermal limits for TSSOP20 in still air.
74VHCT240AMX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74VHCT
- Package/Case:
- 20-SOIC (0.295", 7.50mm 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-SOIC
74VHCT240AMX FAQ
1.How can I place an order for 74VHCT240AMX through Aetrix?
Please submit a Request for Quotation (RFQ) for 74VHCT240AMX 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 74VHCT240AMX reliable?
The price and inventory of 74VHCT240AMX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74VHCT240AMX is usually 5 days.
3.What payment methods are accepted for 74VHCT240AMX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74VHCT240AMX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74VHCT240AMX?
74VHCT240AMX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74VHCT240AMX 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 74VHCT240AMX?
For technical support, including 74VHCT240AMX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74VHCT240AMX requirements.
6.How does Aetrix verify that 74VHCT240AMX is sourced from the original manufacturer or authorized distributors?
All 74VHCT240AMX 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 74VHCT240AMX meets industry standards.
7.What is the process for return or replacement of 74VHCT240AMX?
All 74VHCT240AMX units undergo pre-shipment inspection (PSI). If there is an issue with 74VHCT240AMX, 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 74VHCT240AMX part is unused and in its original packaging.
Return procedure for 74VHCT240AMX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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