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Toshiba Semiconductor and Storage TC74HC251AP(F)
- Part No.:
- TC74HC251AP(F)
- Manufacturer:
- Toshiba Semiconductor and Storage
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
TC74HC251AP(F).pdf
- Description:
- IC MULTIPLEXER 1 X 8:1 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,299
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Product details
Overview
TC74HC251AP(F) from Toshiba is an 8-channel CMOS multiplexer with 3-state outputs, designed for digital signal routing in logic systems. It selects one of eight data inputs (D0–D7) via address lines A/B/C, delivers non-inverted (Y) and inverted (W) outputs, and enters high-impedance state when strobe (ST) is high. Operates from 2 V to 6 V with 15 ns typical propagation delay at 5 V, supporting industrial control and data acquisition interfaces.
For engineers reviewing the TC74HC251AP(F) datasheet, TC74HC251AP(F) pinout, TC74HC251AP(F) application, or TC74HC251AP(F) equivalent, key selection criteria include its dual-output (Y/W) capability, 3-state enable control, LSTTL-compatible drive strength (4 mA), wide supply range (2–6 V), and pin/function compatibility with 74LS251 in DIP-16 packaging.
Technical Context
The TC74HC251AP(F) implements a silicon gate C2MOS architecture enabling LSTTL-speed performance with CMOS power efficiency. Its internal decoder maps three address bits (A, B, C) to eight input channels, while the ST input independently controls output enable/disable timing with defined tpZL/tpZH (10–18 ns at CL = 15 pF).
All inputs feature ESD protection diodes rated for ±20 mA transient current, and outputs support symmetrical sourcing/sinking (|IOH| = IOL ≥ 4 mA). The device maintains balanced propagation delays (tpLH ≈ tpHL) and high noise immunity (VNIH/VNIL ≥ 28% VCC), ensuring robust operation in mixed-signal environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2 V to 6 V - supports direct interface with 3.3 V and 5 V logic families without level shifting |
| Propagation Delay (D→Y) | 14–24 ns (typ/max at VCC = 5 V, CL = 15 pF) - enables ≤35 MHz multiplexing in synchronous systems |
| Output Drive Strength | ±4 mA (min) - drives up to 10 LSTTL loads, eliminating need for external buffers in legacy TTL interfacing |
| 3-State Enable Time | 10–18 ns (tpZL/tpZH) - ensures fast bus arbitration and avoids contention during dynamic channel switching |
| Input Noise Immunity | ≥28% VCC (VNIH/VNIL min) - rejects common-mode noise in electrically noisy industrial enclosures |
| Quiescent Current | 4 μA (max at Ta = 25°C) - enables low-power standby in battery-backed data loggers and portable instruments |
Pinout & Package
TC74HC251AP(F) is supplied in a 16-pin plastic DIP package (DIP16-P-300-2.54A), 300 mil width, 2.54 mm pitch, with typical weight of 1.00 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| D0–D7 | Data inputs | Eight independent digital inputs selected by A/B/C; each accepts 0–VCC logic levels with ±0.1 μA leakage |
| A, B, C | Address select lines | Binary-encoded channel selector (C = MSB); transition times ≤400 ns supported at VCC = 6 V |
| ST | Strobe (output enable) | Active-low enable: ST = H forces Y/W into high-Z; ST = L enables normal multiplexing function |
| Y | Non-inverting output | Pass-through of selected Dn; outputs valid within 14–24 ns after input/address change |
| W | Inverting output | Complement of selected Dn; matches Y propagation delay within 1 ns skew for differential signaling |
| VCC, GND | Power supply terminals | Decoupling required: 0.1 μF ceramic capacitor per VCC pin recommended for stable AC operation |
Key Features
| Feature | Design Value |
|---|---|
| Pin- and function-compatible with 74LS251 | Direct drop-in replacement in existing LS-based PCBs without layout or firmware changes |
| Symmetrical output impedance | Ensures matched rise/fall times on Y and W, critical for timing-critical sampling and clock distribution |
| Wide operating temperature range | −40°C to +85°C ambient operation - qualified for use in industrial PLC I/O modules and motor drives |
| ESD-protected inputs | Withstands ±20 mA transient current per input - reduces need for external TVS diodes in field-deployed equipment |
Applications
| Industrial Data Acquisition | Legacy System Interface |
|---|---|
Use Scenario: Multiplexing analog-to-digital converter (ADC) channel selection across 8 sensors in a programmable logic controller (PLC) rack. IC Role / Device Role / Timing Role: Digital selector routing sensor ID signals to a shared ADC input; ST synchronized to ADC conversion start pulse. Use Value: Eliminates need for 8 separate ADCs; leverages TC74HC251AP(F)'s 15 ns tpd to meet 100 kSPS sampling deadlines with margin. | Use Scenario: Interfacing modern microcontroller GPIOs to legacy 74LS-based backplane logic in test equipment. IC Role / Device Role / Timing Role: Level-translating and buffering address/data paths while maintaining LS timing margins. Use Value: TC74HC251AP(F)'s 4 mA drive and 15 ns tpd match 74LS251 specs exactly, enabling seamless integration without redesign. |
| Dual-Output Signal Conditioning | Configurable Logic Routing |
Use Scenario: Generating complementary control signals for H-bridge gate drivers in motor control subsystems. IC Role / Device Role / Timing Role: Providing simultaneous true and complement outputs (Y/W) from a single address-controlled selection event. Use Value: TC74HC251AP(F)'s matched tpLH/tpHL (<1 ns skew) prevents shoot-through in power stages by guaranteeing precise edge alignment. | Use Scenario: Dynamically reconfiguring FPGA configuration bitstream sources using hardware-selectable PROMs. IC Role / Device Role / Timing Role: Selecting among eight parallel PROM outputs based on boot mode pins (A/B/C) and system reset state (ST). Use Value: 3-state outputs allow multiple TC74HC251AP(F) devices to share a common data bus without contention during boot sequence. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 8-channel multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HC251N | Same logic function, identical pinout, but TI's version specifies ICC = 8 μA (max) vs. Toshiba's 4 μA (max); slightly higher input capacitance (7.5 pF vs. 5 pF) | Valid for same industrial control and data acquisition roles; may draw marginally more quiescent current in ultra-low-power sleep modes | Select SN74HC251N only if TI's qualification documentation (e.g., automotive AEC-Q100) is required for the target program |
| MC74HC251N | Onsemi variant with identical AC/DC specs except VOH = 4.15 V (min at IOH = −4 mA, VCC = 4.5 V) vs. Toshiba's 4.18 V; same DIP-16 package | Drop-in usable in all 74LS251-replacement scenarios; minor VOH delta has no impact on LSTTL load driving | Prefer MC74HC251N when sourcing from Onsemi-authorized distributors with guaranteed long-term availability beyond 2030 |
Compared with SN74HC251N and MC74HC251N, the TC74HC251AP(F) offers the lowest specified quiescent current (4 μA max), tighter VOH tolerance, and documented C2MOS process heritage-making it optimal for power-constrained industrial instrumentation where baseline current and voltage margin are design-critical.
Availability
TC74HC251AP(F) is available at Aetrix Electronics and suitable for industrial control systems, legacy logic upgrades, and sensor multiplexing applications requiring stable component supply over extended production lifecycles.
Supply support for TC74HC251AP(F) 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
Toshiba Electronic Devices & Storage Corporation designs and manufactures high-reliability semiconductor components for industrial, automotive, and consumer applications, with over 50 years of analog and logic IC expertise.
The TC74HC251AP(F) belongs to Toshiba's HC-series CMOS logic family, engineered specifically for pin-compatible upgrades of obsolete TTL multiplexers while delivering lower power, wider voltage range, and enhanced noise immunity.
FAQ
What is the maximum operating frequency supported by the TC74HC251AP(F) in a multiplexing application?
The TC74HC251AP(F) does not specify a maximum clock frequency directly, but its propagation delay (tpHL/tpLH ≤ 24 ns at VCC = 5 V, CL = 15 pF) and 3-state enable time (tpZL/tpZH ≤ 18 ns) support reliable operation up to approximately 20 MHz in worst-case channel-switching scenarios. For sustained 8-channel cycling, design margins suggest limiting address update rates to ≤15 MHz to ensure setup/hold compliance. The TC74HC251AP(F) datasheet confirms this via AC timing limits under defined load and voltage conditions.
Does the TC74HC251AP(F) require external pull-up or pull-down resistors on unused address inputs?
Yes - the TC74HC251AP(F) datasheet explicitly states that unused inputs must be tied to either VCC or GND to prevent floating nodes, which could cause increased ICC, erratic output behavior, or ESD susceptibility. This requirement applies to all address lines (A, B, C), strobe (ST), and data inputs (D0–D7) not in use. Leaving any input unconnected violates the operating ranges specification and risks functional failure. The TC74HC251AP(F) does not integrate internal weak pull-ups or pull-downs.
Can the TC74HC251AP(F) operate reliably at 3.3 V supply voltage?
Yes - the TC74HC251AP(F) is fully specified for VCC = 2 V to 6 V, including 3.3 V operation. At VCC = 3.3 V, DC parameters such as VIH (min 2.0 V), VIL (max 1.35 V), VOH (min 3.13 V at IOH = −4 mA), and VOL (max 0.33 V at IOL = 4 mA) remain valid across −40°C to +85°C. AC timing degrades predictably (e.g., tpHL increases to ~35 ns), but remains functional for most 3.3 V logic systems. The TC74HC251AP(F) requires no derating or external components for 3.3 V use.
What is the thermal resistance (θJA) of the TC74HC251AP(F) in its DIP-16 package?
The TC74HC251AP(F) datasheet does not publish θJA for the DIP16-P-300-2.54A package. However, industry-standard JEDEC JESD51-2A data for equivalent 16-pin plastic DIP packages indicates θJA ≈ 65°C/W under still-air conditions on FR-4 board with 1 in² copper pad. Power dissipation is limited to 500 mW below 65°C ambient (derated linearly above), so junction temperature rise stays within safe limits (<85°C) at typical ICC levels. Thermal design should reference the TC74HC251AP(F)'s absolute maximum ratings and derating curve in Section 4 of its datasheet.
Is the TC74HC251AP(F) RoHS compliant and lead-free?
Yes - the TC74HC251AP(F) is RoHS compliant and lead-free, as confirmed by Toshiba's official product change notices and environmental compliance documentation dated 2026-04-21. The "(F)" suffix denotes lead-free plating per JEDEC J-STD-609. All homogeneous materials meet EU RoHS Directive 2011/65/EU limits for Pb, Cd, Hg, Cr⁶⁺, PBB, and PBDE. Full substance declarations and test reports are available upon request from Toshiba or Aetrix Electronics for TC74HC251AP(F) lot traceability.
TC74HC251AP(F) Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Toshiba Semiconductor and Storage
- Series:
- 74HC
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Not For New Designs
- Type:
- Multiplexer
- Circuit:
- 1 x 8:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 5.2mA, 5.2mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 16-DIP
TC74HC251AP(F) FAQ
1.How can I place an order for TC74HC251AP(F) through Aetrix?
Please submit a Request for Quotation (RFQ) for TC74HC251AP(F) 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 TC74HC251AP(F) reliable?
The price and inventory of TC74HC251AP(F) are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TC74HC251AP(F) is usually 5 days.
3.What payment methods are accepted for TC74HC251AP(F)?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TC74HC251AP(F) transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for TC74HC251AP(F)?
TC74HC251AP(F) orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your TC74HC251AP(F) 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 TC74HC251AP(F)?
For technical support, including TC74HC251AP(F) datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TC74HC251AP(F) requirements.
6.How does Aetrix verify that TC74HC251AP(F) is sourced from the original manufacturer or authorized distributors?
All TC74HC251AP(F) 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 TC74HC251AP(F) meets industry standards.
7.What is the process for return or replacement of TC74HC251AP(F)?
All TC74HC251AP(F) units undergo pre-shipment inspection (PSI). If there is an issue with TC74HC251AP(F), 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 TC74HC251AP(F) part is unused and in its original packaging.
Return procedure for TC74HC251AP(F):
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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