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onsemi MC74HC240AFELG
- Part No.:
- MC74HC240AFELG
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
MC74HC240AFELG.pdf
- Description:
- IC BUFFER INVERT 6V SOEIAJ-20
- Quantity:
- Payment:
- Shipping:
Inventory:4,392
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Product details
Overview
MC74HC240AFELG from onsemi is an octal 3-state inverting buffer/line driver with two active-low output enables, operating from 2.0 V to 6.0 V, delivering ±7.8 mA output drive at 6.0 V, and supporting industrial temperature range (–55 °C to +125 °C) in a TSSOP-20 package for memory address buffering and clock distribution systems.
For engineers reviewing the MC74HC240AFELG datasheet, pinout, applications, or equivalent options, key selection factors include its dual active-low enable control, 15 LSTTL load drive capability, high noise immunity, JEDEC Std. No. 7A compliance, and compatibility with CMOS/NMOS/TTL interfaces without level-shifting.
Technical Context
The MC74HC240AFELG implements eight independent inverting buffers grouped into two 4-bit banks (A and B), each controlled by a dedicated active-low enable (Enable A on Pin 1, Enable B on Pin 19). Outputs enter high-impedance state when either enable is high, enabling bus sharing and bidirectional signal routing.
Designed using high-performance silicon-gate CMOS, it achieves propagation delays as low as 14 ns (tPLH/tPHL at VCC = 6.0 V, TA = 25 °C) and transition times down to 10 ns, with input leakage ≤±0.1 µA and three-state output leakage ≤±0.5 µA at 6.0 V - ensuring low static power and clean signal integrity in mixed-voltage systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2.0 V to 6.0 V - supports direct interface with 3.3 V and 5 V logic domains without voltage translation. |
| Output Drive Strength | ±7.8 mA at VCC = 6.0 V - drives up to 15 LSTTL loads, sufficient for fanout in legacy and mixed-logic backplanes. |
| Propagation Delay | 14 ns max (A→YA or B→YB, VCC = 6.0 V) - enables reliable timing in sub-70 MHz clock distribution and address latching. |
| Input Leakage Current | ±0.1 µA max (VCC = 6.0 V) - minimizes standby current in battery-backed or low-power hold modes. |
| Operating Temperature | –55 °C to +125 °C - qualified for under-hood automotive, industrial control, and extended-environment embedded systems. |
| ESD Withstand | >2000 V HBM - provides robust handling during PCB assembly and field service without additional protection circuitry. |
Pinout & Package
TSSOP-20 package (Case 948E), 0.65 mm pitch, 6.5 mm × 4.4 mm body, 1.2 mm max height, Pb-free and RoHS compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | Active-Low Output Enable (Enable A, Enable B) | Independent control of A-group (YA1–YA4) and B-group (YB1–YB4); high = high-Z, low = enabled/inverting. |
| 2, 4, 6, 8 | Data Inputs (A1–A4) | Invert and route to YA1–YA4 when Enable A = low; tied high/low if unused per design rule #3. |
| 11, 13, 15, 17 | Data Inputs (B1–B4) | Invert and route to YB1–YB4 when Enable B = low; must not float - requires explicit biasing. |
| 18, 16, 14, 12 | Inverting Outputs (YA1–YA4) | Complement of A1–A4 when Enable A = low; high-impedance otherwise - enables bus contention avoidance. |
| 9, 7, 5, 3 | Inverting Outputs (YB1–YB4) | Complement of B1–B4 when Enable B = low; electrically isolated from YA group for dual-bank operation. |
| 10 | GND | Reference return for all inputs, outputs, and internal logic - must be low-inductance connection to minimize ground bounce. |
| 20 | VCC | Primary power supply for CMOS core - bypassing with 0.1 µF ceramic capacitor near pin required for stable AC performance. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent 4-bit banks | Enables simultaneous control of two data buses (e.g., address/data separation) with separate enable timing and routing. |
| JEDEC Std. No. 7A compliance | Guarantees interoperability with legacy TTL/LS logic families and ensures predictable timing across voltage and temperature. |
| High noise immunity | CMOS input thresholds (VIH ≥ 70% VCC, VIL ≤ 30% VCC) reject >400 mV of coupled noise on shared PCB traces. |
| Low dynamic power consumption | CPD = 32 pF/channel - limits switching current in high-frequency clock trees, reducing thermal load and EMI. |
| AEC-Q100 qualified variant available | MC74HC240ADTR2G−Q supports automotive applications with PPAP documentation and controlled change management. |
Applications
| Memory Address Buffering | Industrial PLC I/O Expansion |
|---|---|
Use Scenario: Driving 16-bit address lines from a microcontroller to multiple SRAM or EPROM devices on a shared bus. IC Role / Device Role / Timing Role: Octal inverting buffer with 3-state control isolates MCU address outputs and prevents contention during bus arbitration. Use Value: Dual enable pins allow staggered activation of upper/lower address bytes, reducing simultaneous switching noise and meeting setup/hold timing for parallel memory access. | Use Scenario: Interfacing a 3.3 V FPGA I/O bank to 24 V industrial sensors and actuators via level-translating digital inputs/outputs. IC Role / Device Role / Timing Role: Inverting line receiver/buffer translating between CMOS logic levels and opto-isolated field-side signals. Use Value: 2.0–6.0 V operation allows direct connection to 5 V sensor supply rails; high noise immunity rejects EMI from motor drives and solenoids. |
| Legacy System Bus Interface | Test Equipment Signal Conditioning |
Use Scenario: Replacing obsolete 74LS240 in retro-computing or instrumentation backplanes requiring TTL-compatible drive. IC Role / Device Role / Timing Role: Pinout-identical CMOS upgrade providing LS240 functionality with lower power and wider voltage margin. Use Value: 15 LSTTL load drive and identical pin assignment enable drop-in replacement without PCB redesign or firmware changes. | Use Scenario: Conditioning clock and trigger signals in automated test equipment before distribution to multiple DUT channels. IC Role / Device Role / Timing Role: Low-skew inverting buffer with fast propagation (14 ns) and tight transition time (10 ns) preserving edge fidelity. Use Value: Matched delay paths across YA/YB groups ensure synchronous signal arrival across 8-channel test fixtures, minimizing channel-to-channel skew. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal inverting buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HC240N | Dual active-low enables; identical logic function and DC specs; SOIC-20 only (no TSSOP option). | Same use cases but lacks TSSOP-20 footprint - requires PCB layout change for surface-mount density-critical designs. | Select SN74HC240N only if SOIC-20 is acceptable and lead-time for MC74HC240AFELG is constrained. |
| 74VHC240M | Higher speed (tPLH = 5.5 ns @ 5 V), lower ICC (2 µA typ), but narrower VCC range (2.0–5.5 V) and no AEC-Q100 variant. | Better for high-frequency clock fanout (>100 MHz), but unsuitable for 6.0 V systems or automotive qualification requirements. | Choose 74VHC240M when maximum speed and ultra-low quiescent current outweigh 6.0 V support and automotive compliance needs. |
Compared with SN74HC240N and 74VHC240M, the MC74HC240AFELG uniquely combines TSSOP-20 packaging, full 2.0–6.0 V operation, AEC-Q100-qualified variants, and proven industrial temperature reliability - making it optimal for space-constrained, multi-rail, and automotive-grade designs where pinout compatibility and long-term supply stability matter.
Availability
MC74HC240AFELG is available at Aetrix Electronics and suitable for industrial automation, automotive ECUs, and legacy system upgrades requiring stable component supply, long-lifecycle support, and RoHS-compliant TSSOP packaging.
Supply support for MC74HC240AFELG 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 focused on energy-efficient innovation for automotive, industrial, cloud, medical, and IoT applications.
The MC74HC240AFELG belongs to onsemi's HC logic family - designed for pin-compatible upgrades of legacy TTL/LS devices while delivering CMOS power efficiency, wide voltage operation, and industrial-grade reliability.
FAQ
What is the maximum output current specification for MC74HC240AFELG?
The MC74HC240AFELG specifies ±7.8 mA output current per pin at VCC = 6.0 V, which corresponds to driving up to 15 LSTTL loads. This value is guaranteed across the full operating temperature range (–55 °C to +125 °C) and defines the device's fanout capability in bus-driving applications. Exceeding this current may cause VOL/VOH degradation or thermal stress.
Does MC74HC240AFELG support 3.3 V logic systems?
Yes, MC74HC240AFELG fully supports 3.3 V operation: its recommended VCC range is 2.0 V to 6.0 V, and all DC and AC specifications - including VIH (≥2.1 V), VIL (≤0.9 V), VOH (≥3.98 V), and VOL (≤0.33 V) - are guaranteed at VCC = 3.3 V. It interfaces directly with 3.3 V CMOS and mixed-voltage systems without level shifters.
Can unused inputs on MC74HC240AFELG be left floating?
No, unused inputs on MC74HC240AFELG must not be left floating. Per datasheet Note 3, all inputs - including A1–A4, B1–B4, Enable A, and Enable B - must be tied to a defined logic level (VCC or GND) to prevent increased ICC, erratic output behavior, or ESD susceptibility. Pull-up or pull-down resistors (typically 10 kΩ) are recommended for unconnected controls.
What is the thermal resistance (θJA) of MC74HC240AFELG in its TSSOP-20 package?
The MC74HC240AFELG in TSSOP-20 package has a junction-to-ambient thermal resistance (θJA) of 150 °C/W, measured per JESD51-7 on a standard FR4 board with minimum pad spacing and no airflow. This value informs thermal design margins - for example, at 100 mW dissipation, junction temperature rise above ambient is ~15 °C.
Is MC74HC240AFELG pin-compatible with the 74LS240?
Yes, MC74HC240AFELG is pin-compatible with the 74LS240, as explicitly stated in the datasheet: "The MC74HC240A is identical in pinout to the LS240." This includes matching pin assignments for all inputs, outputs, VCC, and GND - enabling direct replacement in existing LS240-based PCBs without layout modification.
MC74HC240AFELG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74HC
- 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:
- 7.8mA, 7.8mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOEIAJ-20
MC74HC240AFELG FAQ
1.How can I place an order for MC74HC240AFELG through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74HC240AFELG 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 MC74HC240AFELG reliable?
The price and inventory of MC74HC240AFELG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74HC240AFELG is usually 5 days.
3.What payment methods are accepted for MC74HC240AFELG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC74HC240AFELG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC74HC240AFELG?
MC74HC240AFELG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74HC240AFELG 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 MC74HC240AFELG?
For technical support, including MC74HC240AFELG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74HC240AFELG requirements.
6.How does Aetrix verify that MC74HC240AFELG is sourced from the original manufacturer or authorized distributors?
All MC74HC240AFELG 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 MC74HC240AFELG meets industry standards.
7.What is the process for return or replacement of MC74HC240AFELG?
All MC74HC240AFELG units undergo pre-shipment inspection (PSI). If there is an issue with MC74HC240AFELG, 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 MC74HC240AFELG part is unused and in its original packaging.
Return procedure for MC74HC240AFELG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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