SN74LVC240A - Octal Buffer/Driver 3-State 3.3V | Texas Instruments
MPN: SN74LVC240A β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.55 | $0.55 |
| 10 | $0.46 | $4.60 |
| 100 | $0.31 | $31.00 |
| 500 | $0.24 | $120.00 |
| 1,000 | $0.19 | $190.00 |
Drop-in alternatives for SN74LVC240A β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
SN74LVC240APWRQ1
β Drop-Inπ Reference alternative (not in catalog)
SN74LV240A
β Drop-Inβ In Stock
$0.19 / Unit
View Datasheet βSN74LVC244APWR
β‘ Same Packageβ In Stock
$0.26 / Unit
View Datasheet β74LVC240A
β Drop-Inπ Reference alternative (not in catalog)
MC74LCX240A
β Drop-Inπ Reference alternative (not in catalog)
74LVC240A
β Drop-Inπ Reference alternative (not in catalog)
SN74LVC240A Maximum Ratings & Electrical Characteristics
| Function | Octal inverting buffer/driver with 3-state outputs |
| Supply Voltage Range | 1.65 V to 3.6 V |
| Input Tolerance | 5.5 V on inputs (mixed-mode operation) |
| Channels | 8 (two 4-bit banks, separate OE) |
| Output Type | 3-state inverting |
| Propagation Delay (tpd) | 3.3 ns typical at 3.3 V |
| Max Capacitive Load | 50 pF for full datasheet compliance |
| Technology | CMOS (LVC) |
| Operating Temperature | -40C to +125C |
| Packages | SOIC-20 (DW), TSSOP-20 (PW), SSOP-20 (DB) |
| Mounting Type | Surface Mount |
| Output Enable | 2x active-low OE inputs |
| Output Ground Bounce (VOLP) | Typ. < 0.8 V at VCC = 3.3 V, 25C |
| Output Undershoot (VOHV) | Typ. > 2 V at VCC = 3.3 V, 25C |
| RoHS Status | Compliant |
| Automotive Variant | SN74LVC240APWRQ1 (AEC-Q100) |
SN74LVC240A Pin Configuration
| Pin 1 | OE1 β Output enable 1, active low (bank 1) |
| Pin 2 | 1A1 β Bank 1 input 1 |
| Pin 3 | 1Y4 β Bank 1 output 4 (inverted) |
| Pin 4 | 1A2 β Bank 1 input 2 |
| Pin 5 | 1Y3 β Bank 1 output 3 (inverted) |
| Pin 6 | 1A3 β Bank 1 input 3 |
| Pin 7 | 1Y2 β Bank 1 output 2 (inverted) |
| Pin 8 | 1A4 β Bank 1 input 4 |
| Pin 9 | 1Y1 β Bank 1 output 1 (inverted) |
| Pin 10 | GND β Ground |
| Pin 11 | 2Y1 β Bank 2 output 1 (inverted) |
| Pin 12 | 2A4 β Bank 2 input 4 |
| Pin 13 | 2Y2 β Bank 2 output 2 (inverted) |
| Pin 14 | 2A3 β Bank 2 input 3 |
| Pin 15 | 2Y3 β Bank 2 output 3 (inverted) |
| Pin 16 | 2A2 β Bank 2 input 2 |
| Pin 17 | 2Y4 β Bank 2 output 4 (inverted) |
| Pin 18 | 2A1 β Bank 2 input 1 |
| Pin 19 | OE2 β Output enable 2, active low (bank 2) |
| Pin 20 | VCC β Supply, 1.65 V to 3.6 V |
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this digital IC. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
SN74LVC240A is suitable for 6 applications: Memory Address and Control Bus Driving, Clock Distribution and Gating, Mixed-Voltage Bus Interfacing (3.3V to 5V), Automotive Control Module Logic, Industrial PLC and Test-Equipment I/O, Telecom and Networking Line-Card Logic.
Memory Address and Control Bus Driving
The SN74LVC240A was explicitly designed to improve performance and density of 3-state memory address drivers. Its 3.3-ns typical propagation delay at 3.3 V keeps address-setup margins tight in SRAM/DRAM interfaces, while the 3-state outputs let multiple masters share a common address bus without contention. The two independent 4-bit banks, each with its own active-low OE, allow word-wide bus gating. With 5.5-V tolerant inputs it bridges legacy 5-V memory control signals to a 3.3-V bus directly, avoiding external level shifting.
Recommended
Clock Distribution and Gating
As a clock driver, the SN74LVC240A offers low output ground bounce (VOLP) and controlled VOHV undershoot, preserving clock edge quality across a backplane or board. Its strong CMOS output drives up to 50 pF within datasheet timing guarantees, adequate for multiple clock loads per channel. The dual-bank OE structure enables enabling/disabling of separate clock domains for power management or test isolation. Because propagation delay is fast and symmetric, added skew is minimal, keeping per-clock-domain skew budgets achievable in distributed clock trees.
Recommended
Mixed-Voltage Bus Interfacing (3.3V to 5V)
The SN74LVC240A accepts input voltages up to 5.5 V on all ports while operating from a 3.3-V rail, making it a simple, low-cost translator for 5-V legacy logic into 3.3-V systems. This is common when retrofitting industrial I/O cards, motor-drive controllers, or telecom line cards that still carry 5-V TTL signals. Using the '240 as a receive buffer eliminates discrete level-shifter ICs; its CMOS inputs add negligible loading to the 5-V bus while its 3-state outputs isolate the 3.3-V side during bus arbitration.
Recommended
Automotive Control Module Logic
For automotive ECU and body-control modules, the AEC-Q100-qualified variant SN74LVC240APWRQ1 provides the same inverting octal 3-state buffering with full automotive temperature and quality qualification. It is used to buffer sensor-enable lines, gate actuator command buses, and isolate diagnostic buses during fault conditions. The wide 1.65-3.6 V range tolerates cold-crank transients on regulated 3.3-V rails, and the TSSOP-20 package fits high-density module PCBs with standard reflow assembly.
Recommended
Industrial PLC and Test-Equipment I/O
In PLC digital-input cards and automated test equipment, the SN74LVC240A buffers field-side signals into controller logic and provides 3-state isolation during backplane reconfiguration. Its CMOS technology keeps static power negligible across dozens of channel-buffer ICs per card, while the 50-pF drive capability handles cable and connector capacitance on front-panel runs. Wide -40C to +125C operation covers unconditioned cabinets, and the SOIC-20 DW package suits hand-repairable industrial boards.
Recommended
Telecom and Networking Line-Card Logic
Telecom line cards use the SN74LVC240A for bus-oriented receiver and transmitter functions: gating control buses to hot-swap sections, inverting active-low chip selects, and buffering status flags back to the management controller. Low VOLP/VOHV specifications keep signal integrity stable on the long traces typical of line-card layouts, and the 3-state outputs support multi-card backplane sharing. The 3.3-ns typical delay adds negligible latency to control paths in redundant, failover-oriented architectures.
Recommended
Recommended Products Summary
Engineering reference data for SN74LVC240A β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SN74LVC240APWRQ1 | SN74LV240A | 74LVC240A | MC74LCX240A |
|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Nexperia | onsemi |
| Package | SOIC-20 (DW) / TSSOP-20 (PW) | TSSOP-20 (PW) - same | SOIC-20 / TSSOP-20 - same | SOIC-20 / TSSOP-20 - same | SOIC-20 / TSSOP-20 - same |
| Supply Voltage Range | 1.65 V to 3.6 V | 1.65 V to 3.6 V | 2.7 V to 3.6 V | 1.65 V to 3.6 V | 2.0 V to 3.6 V |
| 5.5-V Tolerant Inputs | Yes | Yes | Yes | Yes | Yes |
| Output Polarity | Inverting | Inverting | Inverting | Inverting | Inverting |
| Typical tpd at 3.3 V | 3.3 ns | 3.3 ns (same die) | [DATA_NEEDED] | [DATA_NEEDED] | [DATA_NEEDED] |
| AEC-Q100 Qualification | No (standard grade) | Yes (Q1) | No | No | No |
| Operating Temperature | -40C to +125C | -40C to +125C | -40C to +125C | -40C to +125C | -40C to +85C |
| Price (1 pc, as of 2026-08-29) | ~$0.55 | ~$0.70 | ~$0.50 | ~$0.45 | ~$0.50 |
Key Differentiators
- 1.65 V minimum operation (vs MC74LCX240A)
- Automotive Q1 variant available on same die (vs 74LVC240A (Nexperia))
- Trade-off: 2.7-3.6 V optimized LV240 offers lower cost (vs SN74LV240A)
Design Notes
Place a 0.1 uF ceramic decoupling capacitor within 2 mm of the VCC (pin 20) pin, plus one bulk 4.7-10 uF capacitor per device group. Simultaneous switching of eight outputs causes ground bounce; TI datasheet VOLP/VOHV specs assume solid ground return, so use a continuous ground plane rather than thermal-relief spokes on the GND pin (pin 10).
The 50-pF rated load defines the guaranteed-timing boundary: each output driving a long trace or multiple gate loads should be budgeted by estimating Cload = trace capacitance (~1-2 pF/cm) plus receiver inputs. Above 50 pF, tpd rises and edge rates slow - add series resistance (22-33 ohm) on heavily loaded lines to control ringing rather than relying on the driver alone.
The OE pins are active low: tying them high puts outputs in high-impedance, which is a common bring-up failure. Never leave OE or A inputs floating - CMOS inputs floating cause oscillation and excess current; terminate unused inputs to VCC or GND. Note that the '240 pinout differs from the '244 (non-inverting), so PCB footprints are not interchangeable between the two functions.
Compliance Information
RoHS compliant per TI product page. AEC-Q100 available only on SN74LVC240APWRQ1 variant.
