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Texas Instruments SN74AC240PWR
- Part No.:
- SN74AC240PWR
- Manufacturer:
- Texas Instruments
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74AC240PWR.pdf
- Description:
- IC BUFF INVERT 6V 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,062
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Product details
Overview
SN74AC240PWR from Texas Instruments is an octal 3-state buffer/driver IC designed for bus-oriented signal routing in memory address, clock distribution, and data transmission systems. It operates from 2V to 6V, delivers ≤6.5ns propagation delay at 5V, and accepts input voltages up to 6V - enabling mixed-voltage interface bridging in industrial control backplanes.
For engineers reviewing the SN74AC240PWR datasheet, SN74AC240PWR pinout, SN74AC240PWR application, or SN74AC240PWR equivalent, this page provides verified functional modes, TSSOP-20 package dimensions, switching characteristics across VCC = 3.3V/5V, high-impedance output behavior, and validated alternative options for bus buffering in space-constrained designs.
Technical Context
The SN74AC240PWR implements two independent 4-bit noninverting buffers, each with dedicated 3-state output-enable (OE) control. Its logic function is strictly noninverting: when OE is low, A inputs pass directly to Y outputs; when OE is high, all eight outputs enter high-impedance state - no internal inversion occurs during active drive.
It supports rail-to-rail input tolerance (VI up to VCC + 0.5V), meets ±24mA output drive at 4.5V–5.5V, and features CMOS-compatible input thresholds (VIH = 0.7×VCC, VIL = 0.3×VCC). Thermal resistance RθJA is 126.2°C/W in its PW (TSSOP-20) package, consistent with JEDEC MO-153 standards.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2V to 6V - supports direct interfacing between 3.3V and 5V logic domains without level shifters |
| Max tPD @ 5V | 6.5ns - enables reliable operation in 100+ MHz bus timing windows with margin |
| Output Drive | ±24mA @ 4.5V - sufficient to drive 50Ω transmission lines or fan-out to ≥10 LVTTL loads |
| Input Voltage Range | –0.5V to VCC+0.5V - allows safe connection to overvoltage sources or hot-swap scenarios |
| Operating Temp | –40°C to +85°C - qualified for commercial/industrial ambient environments |
| ESD Rating (HBM) | ±2000V - exceeds IEC 61000-4-2 Level 2 requirements for board-level robustness |
| Power Dissipation Cap | 45pF per buffer - defines dynamic power consumption under 1MHz toggle conditions |
Pinout & Package
TSSOP-20 (PW) package: 6.5mm × 6.4mm body size, 0.65mm lead pitch, 1.2mm max height, RoHS-compliant NiPdAu lead finish, MSL Level-1 (260°C peak reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE | Active-low enable for Y1–Y4 outputs | Drives first 4 outputs into high-Z when high; ties to VCC via pullup for power-up safety |
| 1A1–1A4 | Inputs for first buffer group | Noninverting inputs mapped to Y1–Y4; tolerate up to 6V regardless of VCC |
| 2Y1–2Y4 | Outputs for second buffer group | Driven by 2A1–2A4 when 2OE is low; high-Z otherwise |
| 2A1–2A4 | Inputs for second buffer group | Independent of first group; identical electrical specs and voltage tolerance |
| 2OE | Active-low enable for Y1–Y4 of second group | Enables dual-bank isolation - critical for bidirectional bus arbitration |
| VCC (Pin 20) | Power supply | Single-supply operation; requires local 0.1µF ceramic bypass capacitor |
| GND (Pin 10) | Ground reference | Common return for all I/O and supply currents; must be low-inductance path |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail input tolerance | Accepts VI up to VCC+0.5V - eliminates need for external clamping diodes in mixed-voltage systems |
| Dual independent 4-bit banks | Separate 1OE/2OE controls allow staggered enable timing or partial bus isolation |
| Low propagation delay | 6.5ns max at 5V enables use in 100MHz+ synchronous bus applications with setup/hold margin |
| High noise immunity | VIH/VIL thresholds scale with VCC (0.7×/0.3×) - maintains noise margin across 2V–6V supply range |
| CMOS power efficiency | ICC ≤ 40µA at 5.5V - supports low-quiescent-power standby modes in portable equipment |
Applications
| Memory Address Buffering | Industrial Backplane Interface |
|---|---|
Use Scenario: Driving multiplexed address lines from a microcontroller to multiple SRAM or Flash devices on a shared bus. IC Role / Device Role / Timing Role: Noninverting 3-state buffer providing controlled signal launch, fan-out amplification, and bus contention prevention during address decode cycles. Use Value: Enables deterministic timing with ≤6.5ns delay and prevents bus conflicts via independent OE control per 4-bit segment. |
Use Scenario: Interfacing PLC CPU modules with distributed I/O cards over a 24V-tolerant backplane using 5V logic signaling. IC Role / Device Role / Timing Role: Voltage-level agnostic bus driver isolating controller-side logic from field-side transceivers while maintaining signal integrity. Use Value: Input overvoltage tolerance (to 6V) accommodates noisy backplane coupling; ±24mA drive sustains signal edge rates over 15cm traces. |
| Smartphone Baseband Interface | Network Switch Control Plane |
Use Scenario: Routing configuration signals (e.g., PMIC enable, codec reset) between AP and peripheral ICs in tight PCB layouts. IC Role / Device Role / Timing Role: Space-efficient TSSOP-20 buffer decoupling sensitive baseband logic from high-noise power management circuits. Use Value: Small 6.5mm × 6.4mm footprint saves board area; 126.2°C/W thermal resistance supports operation near heat-generating SoCs. |
Use Scenario: Driving LED status indicators, fan control PWM, and EEPROM write-enable signals from a switch ASIC's GPIO bank. IC Role / Device Role / Timing Role: General-purpose output expander providing current gain and 3-state flexibility for discrete control functions. Use Value: Dual OE inputs allow synchronized update of indicator groups; rail-to-rail inputs simplify connection to varied ASIC output standards. |
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 |
|---|---|---|---|
| SN74LVC240APWR | Lower VCC range (1.65V–3.6V); 3.3V-only optimized; 5.5ns tPD @ 3.3V | Better suited for modern low-voltage SoC interfaces; not 5V-tolerant | Select when system operates exclusively at 3.3V and requires lower static current (ICC ≤ 10µA) |
| 74AC240SCX | SOIC-20 package; identical AC specs; same 2V–6V range and 6.5ns tPD | Larger 12.8mm × 10.3mm footprint; higher RθJA (101.2°C/W); no tape-and-reel option listed | Choose for legacy through-hole compatible layouts or where TSSOP handling is impractical |
Compared with SN74AC240PWR, SN74LVC240APWR offers superior low-voltage efficiency but sacrifices 5V interoperability, while 74AC240SCX matches electrical performance exactly but increases board area and thermal resistance - making SN74AC240PWR optimal for compact, mixed-voltage industrial designs requiring proven reliability.
Availability
SN74AC240PWR is available at Aetrix Electronics and suitable for industrial backplane interface, smartphone baseband routing, and network switch control plane applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for SN74AC240PWR 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
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic solutions, with over 50 years of innovation in high-reliability interface ICs.
The SN74AC240PWR belongs to TI's AC-series advanced CMOS logic family, engineered for high-speed, low-power, mixed-voltage bus interfacing in industrial, communications, and consumer electronics.
FAQ
What is the maximum operating voltage for SN74AC240PWR?
The SN74AC240PWR supports a supply voltage range of 2V to 6V. Its absolute maximum rating is 7V on VCC, but continuous operation above 6V is not recommended. Inputs tolerate up to VCC + 0.5V, allowing safe interfacing with 5V signals even when VCC = 3.3V - a key feature confirmed in Section 5.1 and 5.3 of the SCAS512G datasheet.
Does SN74AC240PWR support true bidirectional data flow?
No, SN74AC240PWR is a unidirectional noninverting buffer with separate input (A) and output (Y) terminals. It does not implement bus transceiver functionality. Data flows only from A to Y when the corresponding OE is asserted low; outputs go high-impedance when OE is high. This architecture is explicitly defined in the Function Table (Section 7.3) and Logic Diagram (Figure 7-1) of the SN74AC240PWR datasheet.
What is the thermal resistance (RθJA) of SN74AC240PWR in its TSSOP-20 package?
The junction-to-ambient thermal resistance (RθJA) for SN74AC240PWR in the PW (TSSOP-20) package is 126.2°C/W, as specified in Section 5.4 of the SCAS512G datasheet. This value assumes standard JEDEC 2-layer board conditions and confirms suitability for moderate-power-density industrial PCBs without forced airflow.
Can unused inputs on SN74AC240PWR be left floating?
No. All unused inputs on SN74AC240PWR must be tied to either VCC or GND to prevent undefined logic states and increased ICC. Section 5.3 Note 1 and Layout Guidelines (Section 8.2.1) explicitly require biasing unused inputs - floating pins cause erratic output behavior and elevated power consumption due to CMOS input stage instability.
Is SN74AC240PWR pin-compatible with SN74AC240N (PDIP-20)?
Yes, SN74AC240PWR and SN74AC240N share identical pin numbering and functional assignment per Table 4-1 (Pin Functions) and Figure 4-1 of the datasheet. Both follow the same 20-pin dual-in-line arrangement: Pin 1 = 1OE, Pins 2–9 = 1A1–1A4/2Y4–2Y1, Pin 10 = GND, Pins 11–19 = 2A1–2A4/1Y4–1Y1/2OE, Pin 20 = VCC. Signal mapping and electrical behavior are fully consistent across packages.
SN74AC240PWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AC
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Logic Type:
- Buffer, Inverting
- Number of Elements:
- 2
- Number of Bits per Element:
- 4
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 24mA, 24mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP
SN74AC240PWR FAQ
1.How can I place an order for SN74AC240PWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AC240PWR 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 SN74AC240PWR reliable?
The price and inventory of SN74AC240PWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AC240PWR is usually 5 days.
3.What payment methods are accepted for SN74AC240PWR?
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Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AC240PWR?
SN74AC240PWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AC240PWR 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 SN74AC240PWR?
For technical support, including SN74AC240PWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AC240PWR requirements.
6.How does Aetrix verify that SN74AC240PWR is sourced from the original manufacturer or authorized distributors?
All SN74AC240PWR 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 SN74AC240PWR meets industry standards.
7.What is the process for return or replacement of SN74AC240PWR?
All SN74AC240PWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AC240PWR, 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 SN74AC240PWR part is unused and in its original packaging.
Return procedure for SN74AC240PWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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