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Texas Instruments SN5442AJ
- Part No.:
- SN5442AJ
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- -
- Datasheet:
-
SN5442AJ.pdf
- Description:
- IC DECIMAL DECODER/DRVR TTL
- Quantity:
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- Shipping:
Inventory:912
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Product details
Overview
SN5442AJ from Texas Instruments is a military-grade BCD-to-decimal decoder IC that converts 4-bit binary-coded decimal inputs into active-low 10-line decimal outputs. It operates across –55°C to +125°C, features TTL-compatible inputs/outputs, 8-mA sink output drive, diode-clamped inputs, and guarantees all outputs remain high for invalid BCD codes. It is used in legacy military panel displays and discrete address decoding circuits.
For engineers reviewing the SN5442AJ datasheet, SN5442AJ pinout, SN5442AJ application, or SN5442AJ equivalent, key selection considerations include its military temperature rating, active-low open-collector–compatible outputs, invalid-input fail-safe behavior, and direct compatibility with saturated TTL logic families in fixed-function digital systems.
Technical Context
The SN5442AJ implements full decoding using eight inverters and ten four-input NAND gates, with inverters paired to provide complementary BCD inputs to each NAND gate. Its logic ensures only one output goes low per valid BCD input (0–9), while all ten outputs stay high for inputs 10–15.
It uses standard TTL voltage thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) and delivers –0.4 mA source / 8 mA sink output capability on each of its 10 active-low outputs. Input clamping diodes protect against transient overvoltage, supporting robust operation in noisy environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.75 V to 5.25 V - Ensures stable operation within standard TTL supply tolerance. |
| Operating Temp | –55°C to +125°C - Qualified for full military temperature range per MIL-PRF-38535. |
| Output Type | Active-low, TTL-compatible - Directly drives LED segments or relay drivers without level-shifting. |
| Output Drive | –0.4 mA / 8 mA - Sinks up to 8 mA per output; sufficient for discrete transistor interface or low-power LEDs. |
| Invalid Input Response | All outputs high - Prevents spurious activation in error states (e.g., 1010–1111 BCD). |
| Propagation Delay | 40 ns max (tPLH/tPHL) - Supports synchronous decoding in sub-25-MHz clock domains. |
Pinout & Package
SN5442AJ is supplied in a 16-pin ceramic dual-in-line package (CDIP) with hermetic sealing for military reliability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 6, 7 | BCD Inputs (A, B, C, D) | Active-high TTL inputs; A = LSB, D = MSB; diode-clamped for ESD protection. |
| 3–5, 9–12 | Decimal Outputs (0–9) | Active-low TTL outputs; each sinks 8 mA when asserted; high-impedance when inactive. |
| 13, 14 | NC | No internal connection - left unconnected per datasheet; no routing required. |
| 16 | VCC | +5 V power supply pin - requires local 0.1 µF ceramic decoupling adjacent to pin. |
| 8 | GND | Ground reference - must be connected to system ground plane with low-inductance path. |
Key Features
| Feature | Design Value |
|---|---|
| Full BCD decoding | Exactly one active-low output per valid 0–9 input; eliminates external logic for digit selection. |
| Invalid-input fail-safe | All ten outputs remain high for illegal codes (10–15), preventing unintended device activation. |
| Diode-clamped inputs | Internal clamping diodes limit input voltage swing to safe levels, reducing need for external protection. |
| Military temperature qualification | Tested and screened per MIL-PRF-38535 Class B requirements for extended environmental resilience. |
Applications
| Industrial Panel Displays | Military Instrumentation |
|---|---|
Use Scenario: Driving 7-segment LED displays via discrete segment drivers in analog-digital hybrid test equipment. IC Role / Device Role / Timing Role: BCD-to-decimal decoder providing digit-select signals for multiplexed display control. Use Value: Eliminates microcontroller GPIO overhead by offloading static digit decoding in resource-constrained embedded systems. | Use Scenario: Address decoding for memory-mapped I/O registers in avionics subsystems operating at extreme temperatures. IC Role / Device Role / Timing Role: Fixed-function address decoder enabling peripheral selection in non-volatile control logic. Use Value: Provides deterministic, zero-software-latency decoding immune to radiation-induced soft errors in critical paths. |
| Legacy Test Equipment | Hardwired Control Logic |
Use Scenario: Generating enable signals for decade counters and stepper motor sequencers in calibration benches. IC Role / Device Role / Timing Role: Combinational logic block converting thumbwheel switch inputs into discrete actuator enables. Use Value: Delivers predictable timing (40 ns max delay) without firmware dependency or clock domain crossing. | Use Scenario: Implementing state-machine decode in safety-critical electro-mechanical controllers with no programmable logic. IC Role / Device Role / Timing Role: Glue logic element translating operator input codes into relay driver activation patterns. Use Value: Guarantees fail-safe behavior (all outputs high on invalid input) to prevent hazardous actuator misfires. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar BCD-to-decimal decoding applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN54LS42J | Lower power consumption (19 mW vs. 28 mW), same pinout and timing; uses LS-TTL process. | Preferred where thermal budget is constrained; identical military temp range and CDIP packaging. | Select SN54LS42J if lower static power and compatible propagation delay (45 ns) are acceptable trade-offs. |
| SN7442N | Commercial temperature range (0°C to 70°C); otherwise identical logic, pinout, and drive strength. | Limited to non-military, benign-environment applications such as lab instrumentation or educational kits. | Choose SN7442N only when full military qualification is unnecessary and cost sensitivity is higher. |
Compared with SN54LS42J and SN7442N, the SN5442AJ offers the highest temperature resilience and highest drive strength but consumes more quiescent power-making it optimal for legacy military systems where reliability under stress outweighs power efficiency.
Availability
SN5442AJ is available at Aetrix Electronics and suitable for industrial panel displays, military instrumentation, and legacy test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SN5442AJ 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, embedded processing, and logic ICs with deep heritage in military and aerospace components.
The SN5442AJ belongs to TI's classic TTL logic family designed for deterministic, low-complexity digital decoding in systems where programmability, power efficiency, or modern packaging are secondary to proven reliability and environmental ruggedness.
FAQ
What is the operating temperature range of the SN5442AJ?
The SN5442AJ is characterized for operation from –55°C to +125°C and qualified per MIL-PRF-38535 Class B. This full military temperature range enables use in harsh environments such as airborne, ground vehicle, and space-qualified subsystems where commercial-grade parts would fail. The SN5442AJ maintains specified timing and drive performance across this entire range without derating.
Does the SN5442AJ have active-high or active-low outputs?
The SN5442AJ features active-low decimal outputs (0–9). Each output goes low when selected and remains high otherwise. This matches standard common-anode LED display configurations and simplifies interfacing with NPN transistor drivers or open-collector loads. All outputs default high for invalid BCD inputs (10–15), ensuring fail-safe behavior in the SN5442AJ.
Is the SN5442AJ pin-compatible with the SN7442N?
Yes, the SN5442AJ and SN7442N share identical pinouts, logic function, and electrical characteristics except for temperature rating and packaging. Both use 16-pin DIP footprints (CDIP for SN5442AJ, PDIP for SN7442N), and all signal pins map one-to-one. However, SN5442AJ's ceramic package and military screening make it unsuitable as a drop-in replacement on boards designed for plastic DIP thermal expansion profiles.
What is the maximum output sink current for the SN5442AJ?
The SN5442AJ provides a guaranteed minimum output sink current of 8 mA per decimal output at VOL ≤ 0.5 V, with typical values reaching 12 mA. This allows direct driving of low-current LEDs or interface to standard TTL inputs without external buffers. Source current is limited to –0.4 mA, confirming the SN5442AJ is optimized for sinking loads rather than sourcing.
Can the SN5442AJ be used as a 4-to-16 line decoder?
Yes-the SN5442AJ can be configured as a 4-to-16 line decoder by cascading two devices: one decoding bits A–C for chip select and the other decoding bit D plus A–C for output enable. This configuration leverages the SN5442AJ's inherent logic structure and is documented in TI's Designing With Logic application note (SDYA009C). It does not require additional gates beyond the two SN5442AJ ICs.
SN5442AJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- -
- Circuit:
- -
- Independent Circuits:
- -
- Current - Output High, Low:
- -
- Voltage Supply Source:
- -
- Voltage - Supply:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
SN5442AJ FAQ
1.How can I place an order for SN5442AJ through Aetrix?
Please submit a Request for Quotation (RFQ) for SN5442AJ 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 SN5442AJ reliable?
The price and inventory of SN5442AJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN5442AJ is usually 5 days.
3.What payment methods are accepted for SN5442AJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN5442AJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN5442AJ?
SN5442AJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN5442AJ 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 SN5442AJ?
For technical support, including SN5442AJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN5442AJ requirements.
6.How does Aetrix verify that SN5442AJ is sourced from the original manufacturer or authorized distributors?
All SN5442AJ 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 SN5442AJ meets industry standards.
7.What is the process for return or replacement of SN5442AJ?
All SN5442AJ units undergo pre-shipment inspection (PSI). If there is an issue with SN5442AJ, 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 SN5442AJ part is unused and in its original packaging.
Return procedure for SN5442AJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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