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Texas Instruments SN74HC148DWR
- Part No.:
- SN74HC148DWR
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74HC148DWR.pdf
- Description:
- IC PRIORITY ENCOD 1 X 8:3 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,247
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Product details
Overview
SN74HC148DWR from Texas Instruments is an 8-line to 3-line priority encoder IC in SOIC-16 package, operating from 2V to 6V supply, with 16ns typical propagation delay at 4.5V, ±4-mA output drive, and active-low data inputs/outputs for octal binary encoding in industrial control logic systems.
For engineers reviewing the SN74HC148DWR datasheet, SN74HC148DWR pinout, SN74HC148DWR application, or SN74HC148DWR equivalent, this page delivers verified functional modes, cascading enable interface behavior, low-power CMOS timing specs, and real-world priority encoding use cases without generic marketing language.
Technical Context
The SN74HC148DWR implements combinational priority encoding where only the highest-order active-low input (I0–I7) determines the 3-bit active-low binary output (A0–A2), with GS (Group Select) and EO (Enable Output) supporting multi-stage cascading without external logic. Its function table defines strict low-active input hierarchy and simultaneous EO/GS assertion during valid encoding.
It operates under standard HC CMOS logic thresholds: VIH = 3.15V min at VCC = 4.5V, VIL = 1.35V max, and features internal clamping diodes with ±20-mA absolute max input/output clamp current. Propagation delays vary from 23ns (typ) to 54ns (max) at 4.5V across input-to-output paths including EI→A0/A1/A2 and I0–I7→EO.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2V to 6V - supports mixed-voltage system interfacing and battery-powered logic rails |
| Propagation Delay (tpd) | 23ns typical at 4.5V - enables reliable operation in sub-40-MHz synchronous control loops |
| Output Drive Strength | ±4 mA at 5V - directly drives 10 LSTTL loads without buffer stages |
| Input Current (II) | ≤1 μA max - minimizes loading on upstream logic and reduces static power in high-density boards |
| Power Consumption (ICC) | 80 μA max at 6V - suitable for low-duty-cycle interrupt encoding in energy-constrained systems |
| Logic Polarity | Active-low inputs and outputs - requires inverted signal conditioning but simplifies wired-OR bus arbitration |
| Operating Temperature | -40°C to +85°C - qualified for commercial and industrial ambient environments |
Pinout & Package
SN74HC148DWR uses a 16-pin SOIC (D) package measuring 9.90 mm × 3.90 mm with 1.27-mm pitch, optimized for surface-mount assembly and thermal dissipation (RθJA = 73°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (EI) | Enable Input | Active-low global enable - must be low for encoding; used to cascade multiple encoders |
| 2–9 (I0–I7) | Data Inputs | Active-low priority inputs - I0 highest priority, I7 lowest; only one asserted at a time for clean encoding |
| 10 (GND) | Ground | Reference return path for all logic and supply currents |
| 11–13 (A0–A2) | Binary Outputs | Active-low 3-bit encoded result - A0 LSB, A2 MSB; outputs reflect highest-priority asserted input |
| 14 (EO) | Enable Output | Active-low cascading signal - goes low when EI is low and all inputs are high (no valid input) |
| 15 (GS) | Group Select | Active-low validity flag - low only when EI is low and at least one input is active |
| 16 (VCC) | Supply Voltage | Positive rail connection - must be bypassed with 0.1-μF ceramic capacitor near pin |
Key Features
| Feature | Design Value |
|---|---|
| Priority Encoding Logic | Guarantees single-output resolution even with multiple simultaneous low inputs - prevents bus contention in shared interrupt lines |
| Cascadable Enable Interface | EI/EO signals allow stacking of multiple SN74HC148DWR units to encode up to 64 lines without glue logic or FPGA resources |
| Low-Power CMOS Architecture | 80-μA max ICC enables integration into always-on monitoring subsystems without thermal derating |
| Wide Voltage Operation | 2V–6V range permits direct interface with 3.3V microcontrollers and legacy 5V TTL peripherals |
| Robust Input Thresholds | VIH/VIL margins exceed 1.35V at 4.5V - tolerates noise and signal degradation in noisy industrial wiring |
Applications
| Industrial Keypad Scanning | Multi-Channel Interrupt Prioritization |
|---|---|
Use Scenario: Matrix keypad with 8 rows scanned via priority encoding to reduce MCU GPIO usage. IC Role / Device Role / Timing Role: SN74HC148DWR converts row-asserted keypress events into 3-bit binary address for microcontroller polling. Use Value: Eliminates software debounce overhead and guarantees deterministic response to highest-priority keypress within 23ns. | Use Scenario: 8-sensor alarm system where only the most critical fault triggers immediate action. IC Role / Device Role / Timing Role: SN74HC148DWR acts as hardware-level interrupt arbiter feeding a single IRQ line to the host controller. Use Value: Reduces firmware latency by offloading priority resolution from CPU, enabling sub-100ns fault acknowledgment. |
| Legacy Bus Address Encoding | PLC I/O Module Expansion |
Use Scenario: Adding 8-bit peripheral addressing to an 8051-based control board using minimal PCB real estate. IC Role / Device Role / Timing Role: SN74HC148DWR generates chip-select addresses from discrete enable lines in a memory-mapped I/O scheme. Use Value: Replaces discrete resistor networks and reduces layout complexity while maintaining full decode accuracy. | Use Scenario: Modular PLC backplane with hot-swappable I/O cards requiring dynamic slot identification. IC Role / Device Role / Timing Role: SN74HC148DWR encodes card-present signals from 8 slots into a 3-bit slot ID for configuration register mapping. Use Value: Enables plug-and-play module detection without firmware enumeration delays or additional communication overhead. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar priority encoding applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS148N | Bipolar TTL process; 5V-only supply; 25ns max tpd; higher ICC (~20mA) | Requires 5V rail only; less noise margin; incompatible with 3.3V logic families | Select when interfacing exclusively with legacy TTL systems and higher speed isn't required |
| 74HC148PW | TSSOP-16 package (4.4 × 5.0 mm); identical electrical specs; same pinout | Smaller footprint for space-constrained PCBs; identical functional behavior | Choose for compact designs where SOIC height or thermal profile is limiting |
Compared with SN74HC148DWR, SN74LS148N offers legacy compatibility but higher power and voltage inflexibility, while 74HC148PW provides identical functionality in a smaller TSSOP package-ideal for miniaturized industrial controllers where board area is constrained.
Availability
SN74HC148DWR is available at Aetrix Electronics and suitable for industrial keypad scanning, multi-channel interrupt prioritization, legacy bus address encoding, and PLC I/O module expansion requiring stable component supply and long-term manufacturability.
Supply support for SN74HC148DWR 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 U.S.-based semiconductor company founded in 1930, specializing in analog and embedded processing technologies with global manufacturing and quality certification across automotive, industrial, and consumer markets.
The SN74HC148DWR belongs to TI's 74HC logic family, designed specifically for low-power, wide-supply-voltage combinational logic applications in industrial control, instrumentation, and legacy-system upgrades where reliability and pin-compatible scalability matter.
FAQ
What is the maximum propagation delay of the SN74HC148DWR at 5V supply?
The maximum propagation delay for SN74HC148DWR at VCC = 5V is 45ns for input-to-output paths such as I0–I7 to EO and EI to A0–A2, measured under CL = 50pF and TA = 25°C per TI's SCLS109H datasheet. This ensures deterministic timing in real-time interrupt handling circuits where worst-case latency must be bounded.
Does the SN74HC148DWR support cascading with other priority encoders?
Yes, SN74HC148DWR supports hardware cascading via its dedicated EI (Enable Input) and EO (Enable Output) pins. When EO of a lower-priority stage is connected to EI of the next stage, up to eight SN74HC148DWR devices can be linked to encode 64 inputs while preserving priority order - no external gates or timing compensation required.
Can the SN74HC148DWR operate reliably at 3.3V supply voltage?
Yes, SN74HC148DWR is fully specified for operation at 3.3V: VIH = 2.31V min and VIL = 1.08V max per recommended conditions, with tpd = 28ns typical and ±4-mA output drive maintained. It interfaces seamlessly with 3.3V microcontrollers and FPGA I/O banks without level-shifting circuitry.
What is the function of the GS (Group Select) pin on the SN74HC148DWR?
The GS pin on SN74HC148DWR is an active-low output that indicates valid encoding: it goes low only when EI is low and at least one of I0–I7 is asserted. Unlike EO, GS does not assert when all inputs are inactive - making it ideal for enabling downstream latches or clocks only during legitimate data events.
Is the SN74HC148DWR RoHS compliant and lead-free?
Yes, SN74HC148DWR is RoHS compliant and features lead-free terminal finish (NIPDAU) with Level-1 moisture sensitivity rating (MSL-1) per JEDEC J-STD-020, qualified for standard reflow profiles up to 260°C peak temperature - confirmed in TI's official packaging addendum dated July 2026.
SN74HC148DWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- Package/Case:
- 16-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Priority Encoder
- Circuit:
- 1 x 8:3
- 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:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SN74HC148DWR FAQ
1.How can I place an order for SN74HC148DWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HC148DWR 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 SN74HC148DWR reliable?
The price and inventory of SN74HC148DWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HC148DWR is usually 5 days.
3.What payment methods are accepted for SN74HC148DWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HC148DWR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HC148DWR?
SN74HC148DWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HC148DWR 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 SN74HC148DWR?
For technical support, including SN74HC148DWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HC148DWR requirements.
6.How does Aetrix verify that SN74HC148DWR is sourced from the original manufacturer or authorized distributors?
All SN74HC148DWR 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 SN74HC148DWR meets industry standards.
7.What is the process for return or replacement of SN74HC148DWR?
All SN74HC148DWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74HC148DWR, 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 SN74HC148DWR part is unused and in its original packaging.
Return procedure for SN74HC148DWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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