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Texas Instruments CD74HC147PWT
- Part No.:
- CD74HC147PWT
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
CD74HC147PWT.pdf
- Description:
- IC PRIORITY ENCOD 1X10:4 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:986
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Product details
Overview
CD74HC147PWT from Texas Instruments is a high-speed CMOS 9-input priority encoder that implements 10-line-to-4-line active-low encoding with decimal zero implied. It operates from 2V to 6V, delivers 13ns typical propagation delay at 5V/15pF, and supports industrial temperature range (–55°C to 125°C). It is used in keyboard encoders, interrupt prioritization circuits, and digital control panels requiring compact, low-power logic encoding.
For engineers reviewing the CD74HC147PWT datasheet, CD74HC147PWT pinout, CD74HC147PWT application, or CD74HC147PWT equivalent, this page provides verified functional identity, TSSOP-16 package mapping, truth-table-defined priority behavior, supply-voltage-dependent timing specs, and validated alternatives for legacy design continuity and obsolescence mitigation.
Technical Context
The CD74HC147PWT implements a fixed-priority, active-low 9-input (I0–I9) to 4-output (Y0–Y3) encoder where I9 has highest priority and all outputs go HIGH only when all inputs are HIGH (encoding "zero"). Its silicon-gate CMOS architecture ensures rail-to-rail output swing, buffered I/O, and noise immunity of 30% of VCC at 5V.
It requires no external clock or enable signal - operation is purely combinatorial. Input loading is asymmetric: I4/I5/I8/I9 draw 1.5 unit loads each, while I1/I2/I3/I6/I7 draw 1.1 unit loads, directly impacting fanout and bus drive capability in multi-device systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | High-speed CMOS (HC), compatible with LSTTL input thresholds only at 4.5–5.5V via HCT variants - not applicable here |
| Supply Voltage Range | 2V to 6V - enables direct interface with 3.3V and 5V systems without level shifters |
| Propagation Delay | 13ns typical at VCC = 5V, CL = 15pF - defines maximum operating frequency in synchronous priority resolution paths |
| Input Thresholds | VIH = 1.5V min (at 2V), 3.15V min (at 4.5V), 4.2V min (at 6V); VIL = 0.5V max (at 2V), 1.35V max (at 4.5V) - sets valid logic-high/low voltage margins per supply |
| Operating Temperature | –55°C to +125°C - qualified for aerospace, automotive under-hood, and industrial motor-control environments |
| Output Drive | ±25mA per pin - sufficient to drive 15 LSTTL loads or directly interface with standard 74-series inputs |
| Power Dissipation | CPD = 32pF at 5V - used to calculate dynamic power: PD = VCC² × fi × (CPD + CL) |
Pinout & Package
TSSOP-16 package (PW), 5.00mm × 4.40mm body size, 1.2mm max height, 0.65mm lead pitch, RoHS-compliant NiPdAu finish, MSL Level-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (I4) | Active-low input | Input line 4 with medium priority; asserted LOW to request encoding |
| 2 (I5) | Active-low input | Input line 5 with medium priority; draws 1.5 unit loads |
| 3 (I6) | Active-low input | Input line 6 with medium priority; draws 1.1 unit loads |
| 4 (I7) | Active-low input | Input line 7 with medium priority; draws 1.1 unit loads |
| 5 (I8) | Active-low input | Input line 8 with high priority; draws 1.5 unit loads |
| 6 (Y2) | Active-low output | MSB of 4-bit encoded output (Y3 Y2 Y1 Y0); LOW = logic 1 |
| 7 (Y1) | Active-low output | Second-bit of encoded output; complements priority resolution result |
| 8 (GND) | Ground reference | Primary return path for all internal logic and I/O current |
| 9 (I0) | Active-low input | Lowest-priority input (0); encodes as "all HIGH" when active |
| 10 (I9) | Active-low input | Highest-priority input (9); dominates all other asserted inputs |
| 11 (I1) | Active-low input | Input line 1 with low priority; draws 1.1 unit loads |
| 12 (I2) | Active-low input | Input line 2 with low priority; draws 1.1 unit loads |
| 13 (I3) | Active-low input | Input line 3 with low priority; draws 1.1 unit loads |
| 14 (Y3) | Active-low output | LSB of encoded output; goes LOW only when I9 is asserted |
| 15 (NC) | No connection | Internally unconnected pin - must remain floating or tied to GND/VCC per layout guidelines |
| 16 (VCC) | Positive supply | Single power rail for entire device; requires local 0.1µF bypass capacitor |
Key Features
| Feature | Design Value |
|---|---|
| Buffered inputs and outputs | Reduces capacitive loading effects and improves noise rejection across PCB traces |
| Wide VCC range (2V–6V) | Enables interoperability across mixed-voltage systems without translation circuitry |
| High noise immunity (30% VCC) | Ensures reliable operation in electrically noisy industrial environments with EMI |
| Asymmetric input loading | Optimizes fanout for priority-weighted inputs - critical for deterministic interrupt arbitration |
| –55°C to +125°C operation | Validated performance over full military-grade temperature range |
Applications
| Keyboard Encoder Interface | Industrial Control Panel |
|---|---|
Use Scenario: Encoding keypresses from a 3×3 numeric keypad into 4-bit BCD for microcontroller input. IC Role / Device Role / Timing Role: Priority encoder resolving simultaneous key closures by selecting highest-numbered pressed key. Use Value: Eliminates need for software polling or matrix scanning; reduces MCU GPIO count and firmware overhead. | Use Scenario: Prioritizing fault signals (overtemp, overcurrent, communication loss) in PLC backplane modules. IC Role / Device Role / Timing Role: Hardware-level interrupt arbitration delivering highest-priority fault code to controller within 13ns. Use Value: Guarantees sub-20ns response latency independent of software execution state. |
| Legacy System Upgrade Path | Automotive Body Controller |
Use Scenario: Replacing obsolete 74LS147 in avionics panel interfaces where power and thermal budgets tightened. IC Role / Device Role / Timing Role: Pin-compatible drop-in replacement offering 90% lower quiescent current (8µA vs 80mA). Use Value: Enables compliance with DO-160E power dissipation limits without redesigning PCB layout. | Use Scenario: Encoding door lock status, window position, and mirror adjustment switches in centralized body electronics. IC Role / Device Role / Timing Role: Active-low combinatorial encoder feeding discrete status bits to CAN transceiver input logic. Use Value: Reduces harness wiring count by consolidating 9 switch lines into 4 encoded lines, lowering EMI susceptibility. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar priority encoder applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| CD74HC147M96 | Same HC logic family, SOIC-16 package (9.90mm × 3.90mm), active production status, identical electrical specs | Requires PCB footprint change; better thermal resistance (RθJA = 117.2°C/W vs 137.5°C/W) | Select for new designs needing longer-term availability and improved thermal margin. |
| CD74HCT147E | HCT variant, PDIP-16, 4.5–5.5V only, TTL-compatible inputs (VIL ≤ 0.8V), same pinout and truth table | Not suitable for 3.3V systems; requires 5V rail; higher ICC (up to 490µA) than HC version | Select only when interfacing directly with legacy LSTTL logic and 5V-only supply is available. |
Compared with CD74HC147M96 and CD74HCT147E, the CD74HC147PWT offers smallest board area and widest supply range but highest thermal resistance - making it optimal for space-constrained 2–6V applications where ambient temperature stays below 105°C.
Availability
CD74HC147PWT is available at Aetrix Electronics and suitable for industrial control panels, automotive body electronics, legacy system upgrades, and aerospace interface modules requiring stable component supply and long-lifecycle support.
Supply support for CD74HC147PWT 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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and logic ICs with over 50 years of high-reliability product development.
The CD74HC147PWT belongs to TI's legacy HC logic portfolio, designed specifically for pin-compatible upgrades of 74LS devices in industrial, aerospace, and automotive systems demanding wide voltage operation and extended temperature resilience.
FAQ
What is the function of the NC pin on the CD74HC147PWT?
The NC (No Connection) pin on the CD74HC147PWT is internally unconnected and serves no electrical function. It must be left floating or tied to GND/VCC only if required by PCB mechanical or thermal design rules - never driven actively. This pin does not affect logic operation or timing of the CD74HC147PWT.
Can CD74HC147PWT operate reliably at 3.3V supply?
Yes, CD74HC147PWT is fully specified for 2V to 6V operation, including 3.3V. At VCC = 3.3V, VIH is guaranteed ≥ 2.31V and VIL ≤ 0.99V, providing 0.69V noise margin. Propagation delay increases to ~22ns (typical), and output drive remains ±25mA - making it suitable for 3.3V FPGA/CPLD interface applications.
How does the priority encoding behavior work in CD74HC147PWT?
The CD74HC147PWT assigns fixed priority: I9 (pin 10) is highest, I0 (pin 9) is lowest. When multiple inputs are LOW, only the highest-priority asserted input determines the output code (Y3–Y0). If all nine inputs are HIGH, all four outputs go HIGH - representing decimal "zero". This behavior is purely combinatorial and requires no clock or enable signal.
Is CD74HC147PWT pin-compatible with CD74HCT147E?
Yes, CD74HC147PWT and CD74HCT147E share identical pinout and truth table, but differ in logic family (HC vs HCT), supply range (2–6V vs 4.5–5.5V), and input compatibility (CMOS vs TTL thresholds). They are functionally interchangeable only when VCC = 5V and interfacing with TTL sources - otherwise, CD74HC147PWT must be used for 3.3V or wide-range operation.
What is the maximum fanout capability of CD74HC147PWT at 25°C?
At 25°C and VCC = 5V, CD74HC147PWT can drive up to 15 LSTTL loads per output, based on its ±25mA output current rating and LSTTL input requirements (IIL = –1.6mA, IIH = 40µA). Fanout drops to ~10 loads at –55°C due to increased output impedance, and remains stable up to +125°C per TI characterization data for the CD74HC147PWT.
CD74HC147PWT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Priority Encoder
- Circuit:
- 1 x 10:4
- Independent Circuits:
- 1
- Current - Output High, Low:
- 5.2mA, 5.2mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP
CD74HC147PWT FAQ
1.How can I place an order for CD74HC147PWT through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74HC147PWT 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 CD74HC147PWT reliable?
The price and inventory of CD74HC147PWT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74HC147PWT is usually 5 days.
3.What payment methods are accepted for CD74HC147PWT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74HC147PWT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74HC147PWT?
CD74HC147PWT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74HC147PWT 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 CD74HC147PWT?
For technical support, including CD74HC147PWT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74HC147PWT requirements.
6.How does Aetrix verify that CD74HC147PWT is sourced from the original manufacturer or authorized distributors?
All CD74HC147PWT 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 CD74HC147PWT meets industry standards.
7.What is the process for return or replacement of CD74HC147PWT?
All CD74HC147PWT units undergo pre-shipment inspection (PSI). If there is an issue with CD74HC147PWT, 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 CD74HC147PWT part is unused and in its original packaging.
Return procedure for CD74HC147PWT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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