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Texas Instruments CD74HCT157E
- Part No.:
- CD74HCT157E
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
CD74HCT157E.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,161
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Product details
Overview
CD74HCT157E from Texas Instruments is a quad 2-input non-inverting multiplexer IC operating at 4.5V–5.5V, featuring active-low enable (E), common select (S), and four independent data paths (1Y–4Y). It delivers 25ns typical propagation delay (CL = 50pF, VCC = 4.5V), supports -55°C to +125°C operation, and is used in register-to-bus data routing and logic function generation within industrial control and test equipment.
For engineers reviewing the CD74HCT157E datasheet, CD74HCT157E pinout, CD74HCT157E application, or CD74HCT157E equivalent, key selection criteria include LSTTL-compatible input thresholds (VIL ≤ 0.8V, VIH ≥ 2.0V), guaranteed low-level output forcing when disabled, and PDIP-16 packaging for through-hole prototyping and high-reliability legacy systems.
Technical Context
The CD74HCT157E implements four independent 2:1 multiplexers sharing one Select (S) input and one active-low Enable (E) input. When E is high, all outputs (1Y–4Y) are forced low regardless of S or data inputs - a hard-wired disable behavior distinct from the inverting CD74HCT158.
Its HCT logic family ensures direct compatibility with LSTTL voltage levels while maintaining CMOS power efficiency. Input leakage remains ≤ ±1 µA across temperature, and output drive capability supports up to 10 LSTTL loads under full temperature range, enabling direct interfacing with legacy TTL subsystems without level-shifting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | HCT - enables direct LSTTL input compatibility (VIH ≥ 2.0V, VIL ≤ 0.8V) at 4.5–5.5V supply |
| Supply Voltage Range | 4.5V to 5.5V - restricts use to 5V nominal systems; not tolerant of 3.3V or wide-range rails |
| Propagation Delay (tPLH/tPHL) | 25ns max @ 4.5V, CL = 50pF - defines maximum clock/data rate for synchronous bus arbitration |
| Operating Temperature | -55°C to +125°C - qualified for military, aerospace, and extended-temperature industrial environments |
| Output Drive | 10 LSTTL loads - sufficient to drive multiple legacy TTL inputs without buffering |
| Input Leakage Current | ≤ ±1 µA @ -55°C to +125°C - ensures stable logic states in high-impedance or battery-backed circuits |
| Power Dissipation Capacitance | 70 pF - used with CPD formula (PD = VCC² × fi × (CPD + CL)) to calculate dynamic power at given frequency |
Pinout & Package
CD74HCT157E is housed in a 16-pin plastic dual in-line package (PDIP-N), with 0.3-inch body width and standard through-hole mounting. Pin 1 is located at the top-left corner adjacent to the notch or dot marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | E (Enable) | Active-low global enable; when high, forces all Y outputs low - critical for bus contention avoidance |
| 2 | 1I0 | Data input 0 for channel 1 - connects to first source register or signal path |
| 3 | 1I1 | Data input 1 for channel 1 - selects alternate source for same output |
| 4 | 1Y | Non-inverting output for channel 1 - mirrors selected input (1I0 or 1I1) based on S |
| 5 | 2I0 | Data input 0 for channel 2 - independent of channel 1; supports parallel 4-bit selection |
| 6 | 2I1 | Data input 1 for channel 2 - enables simultaneous 4-bit multiplexing under shared S/E control |
| 7 | GND | Ground reference - must be low-impedance connection to minimize noise coupling into logic thresholds |
| 8 | 2Y | Non-inverting output for channel 2 - maintains consistent polarity across all four channels |
| 9 | 3Y | Non-inverting output for channel 3 - identical timing and drive strength as 1Y/2Y/4Y |
| 10 | 3I1 | Data input 1 for channel 3 - completes symmetric 4-channel structure |
| 11 | 3I0 | Data input 0 for channel 3 - matches pinout order of other I0/I1 pairs |
| 12 | 4Y | Non-inverting output for channel 4 - final output in quad configuration |
| 13 | 4I1 | Data input 1 for channel 4 - enables full 4-bit data path selection |
| 14 | VCC | Positive supply - requires local 0.1µF ceramic decoupling capacitor near pin |
| 15 | 4I0 | Data input 0 for channel 4 - completes input set for fourth multiplexer |
| 16 | S (Select) | Common 2:1 selector - determines whether I0 or I1 drives each Y output simultaneously |
Key Features
| Feature | Design Value |
|---|---|
| Non-inverting quad 2:1 multiplexing | Four independent outputs replicate selected input without inversion - simplifies logic design vs. 158 variant |
| Active-low enable with forced-low outputs | When E = HIGH, all Y outputs go LOW - prevents floating or undefined states during disable |
| LSTTL-compatible input thresholds | VIL ≤ 0.8V and VIH ≥ 2.0V at VCC = 4.5–5.5V - eliminates need for external level shifters with legacy TTL |
| Wide temperature operation (-55°C to +125°C) | Validated performance across full military-grade range - suitable for engine control, avionics, and downhole tools |
| Low quiescent current (ICC ≤ 160 µA) | Enables use in low-power standby modes where continuous logic monitoring is required |
Applications
| Industrial PLC I/O Multiplexing | Automotive Sensor Signal Routing |
|---|---|
Use Scenario: Consolidating analog/digital sensor inputs from multiple engine subsystems onto a shared ADC or microcontroller bus. IC Role / Device Role / Timing Role: CD74HCT157E acts as a hardware-selectable signal router, using vehicle ECU-controlled S and E lines to isolate or combine sensor streams before digitization. Use Value: Reduces microcontroller GPIO count and PCB trace count by 4:1 per device, while maintaining deterministic latency (<38ns worst-case propagation). |
Use Scenario: Switching between redundant brake pressure sensors or dual oxygen sensor outputs in safety-critical powertrain modules. IC Role / Device Role / Timing Role: CD74HCT157E provides fail-safe signal selection under ECU supervision - E line disables all outputs during fault conditions to prevent erroneous readings. Use Value: Enables hardware-level redundancy management without software polling delay; forced-low outputs guarantee known state during diagnostics or limp-home mode. |
| Test Equipment Signal Path Switching | Military Radio Baseband Selection |
Use Scenario: Configuring automated test fixtures to route calibration signals or DUT outputs to measurement instruments via programmable control. IC Role / Device Role / Timing Role: CD74HCT157E serves as a static-path selector controlled by FPGA GPIOs, supporting precise timing alignment due to matched propagation delays across channels. Use Value: Eliminates mechanical relay wear and bounce; 25ns channel-to-channel skew ensures synchronized sampling of multi-channel DUT responses. |
Use Scenario: Selecting between encrypted and clear-text baseband data paths in secure HF/VHF radios operating in extreme environmental conditions. IC Role / Device Role / Timing Role: CD74HCT157E functions as a hardened signal gate in the RF front-end control plane, activated only during mode transitions to avoid RF leakage. Use Value: -55°C to +125°C rating ensures uninterrupted operation in desert or arctic deployments; PDIP package withstands thermal cycling better than SOIC in sealed enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad 2-input multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT157N | Same HCT logic, identical pinout and electrical specs; TI's newer catalog version with updated process and RoHS compliance | Preferred for new designs requiring TI's current production support and longer-term availability | Select SN74HCT157N when sourcing new production builds or requiring TI's latest quality and reliability documentation |
| CD74HC157E | Same pinout and function but HC family: 2V–6V supply, higher VIH/VIL thresholds (VIH ≥ 3.15V @ 4.5V), no LSTTL compatibility | Suitable only in pure CMOS systems; incompatible with legacy TTL inputs without level translation | Choose CD74HC157E only if operating outside 4.5–5.5V or interfacing exclusively with CMOS logic |
Compared with CD74HCT157E, SN74HCT157N offers identical functionality with enhanced long-term supply assurance, while CD74HC157E trades LSTTL compatibility for wider voltage flexibility - making the HCT variant essential for mixed-logic or legacy-TTL interface scenarios.
Availability
CD74HCT157E is available at Aetrix Electronics and suitable for industrial control systems, automotive powertrain modules, and military communications equipment requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for CD74HCT157E 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 leader specializing in analog, embedded processing, and logic solutions, with decades of heritage in high-reliability logic families.
The CD74HCT157E belongs to TI's legacy High-Speed CMOS (HCT) logic portfolio, engineered specifically for seamless integration into 5V systems coexisting with older TTL components - emphasizing interoperability, ruggedness, and temperature resilience.
FAQ
What is the supply voltage range for CD74HCT157E?
The CD74HCT157E operates strictly within 4.5V to 5.5V. It is not rated for 3.3V or broader voltage rails. This narrow range ensures guaranteed LSTTL-compatible input thresholds (VIH ≥ 2.0V, VIL ≤ 0.8V) and stable output drive. Operating outside this window may cause incorrect logic interpretation or excessive ICC, so proper 5V regulation is mandatory for reliable CD74HCT157E performance.
How does the enable (E) pin behave on CD74HCT157E?
On the CD74HCT157E, the E pin is active-low: when E = LOW, normal multiplexing occurs based on S and data inputs; when E = HIGH, all four outputs (1Y–4Y) are forcibly driven LOW, regardless of S or I0/I1 states. This hard-wired disable behavior prevents bus contention and ensures predictable system-level reset or isolation - a key distinction from the inverting CD74HCT158 variant.
Is CD74HCT157E pin-compatible with CD74HC157E?
Yes, CD74HCT157E and CD74HC157E share identical PDIP-16 pinouts and functional block diagrams. However, they differ electrically: CD74HCT157E supports LSTTL inputs (VIH ≥ 2.0V), while CD74HC157E requires higher VIH (≥3.15V @ 4.5V) and operates from 2V–6V. Interchangeability depends entirely on input source compatibility - never assume drop-in replacement without verifying driver logic family.
What is the maximum propagation delay of CD74HCT157E at 5V?
At VCC = 4.5V and CL = 50pF, the CD74HCT157E exhibits a maximum propagation delay of 38ns over the full -55°C to +125°C range. At 25°C, typical delay is 25ns. This specification applies to both tPLH and tPHL (data-to-output), ensuring symmetrical timing for bidirectional or clock-synchronized applications using the CD74HCT157E.
Does CD74HCT157E support operation at -55°C?
Yes, CD74HCT157E is fully specified and tested for operation from -55°C to +125°C. Its absolute maximum ratings, DC electrical characteristics, and switching parameters are all validated across this extended temperature range - confirming suitability for aerospace, defense, and oilfield electronics where cold-start reliability is critical. No derating or special handling is required for CD74HCT157E at minimum temperature.
CD74HCT157E Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- Multiplexer
- Circuit:
- 4 x 2:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 4mA, 4mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 16-PDIP
CD74HCT157E FAQ
1.How can I place an order for CD74HCT157E through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74HCT157E 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 CD74HCT157E reliable?
The price and inventory of CD74HCT157E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74HCT157E is usually 5 days.
3.What payment methods are accepted for CD74HCT157E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74HCT157E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74HCT157E?
CD74HCT157E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74HCT157E 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 CD74HCT157E?
For technical support, including CD74HCT157E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74HCT157E requirements.
6.How does Aetrix verify that CD74HCT157E is sourced from the original manufacturer or authorized distributors?
All CD74HCT157E 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 CD74HCT157E meets industry standards.
7.What is the process for return or replacement of CD74HCT157E?
All CD74HCT157E units undergo pre-shipment inspection (PSI). If there is an issue with CD74HCT157E, 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 CD74HCT157E part is unused and in its original packaging.
Return procedure for CD74HCT157E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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