My Inquiry
My Account
Texas Instruments SN74HCT157D
- Part No.:
- SN74HCT157D
- Manufacturer:
- Texas Instruments
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74HCT157D.pdf
- Description:
- IC MULTIPLEXER 4 X 2:1 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:311
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SN74HCT157D from Texas Instruments is a quad 2-line-to-1-line data selector/multiplexer IC in SOIC-16 package, operating at 4.5 V–5.5 V, with typical propagation delay of 15 ns at 5.5 V, ±6-mA output drive, and TTL-compatible inputs. It routes one of two 4-bit data sources to four outputs under select (A/B) and strobe (G) control, used in digital logic routing, bus arbitration, and address/data path switching.
For engineers reviewing the SN74HCT157D datasheet, SN74HCT157D pinout, SN74HCT157D application, or SN74HCT157D equivalent, this page delivers verified electrical specs, functional truth table alignment, SOIC-16 terminal mapping, real-world use cases in industrial control and instrumentation, and validated alternative parts for design continuity.
Technical Context
The SN74HCT157D implements four independent 2:1 multiplexers with a common strobe (G) enable and shared select (A/B) line. Each Y output reflects the selected A or B input only when G is low; all outputs go high-impedance when G is high.
Its HCT logic family ensures CMOS power efficiency with TTL-level input thresholds (VIH = 2 V min, VIL = 0.8 V max), buffered inputs/outputs, and guaranteed operation across −40°C to +85°C. Input clamp current is ±20 mA, and absolute max VCC is 7 V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures compatibility with standard 5-V TTL and mixed-voltage logic systems without level shifting. |
| Propagation Delay (tpd) | 15 ns (typ) at VCC = 5.5 V, CL = 50 pF - Supports 33+ MHz clocked data selection in synchronous digital systems. |
| Output Drive | ±6 mA at VCC = 4.5 V - Directly drives 15 LSTTL loads, eliminating need for external buffers in legacy TTL interfacing. |
| Input Current (II) | ±1 µA max at VCC = 5.5 V - Enables high-fanout designs with minimal loading on upstream logic stages. |
| Power Consumption (ICC) | 80 µA max at VCC = 5.5 V - Delivers ultra-low static power for battery-backed or energy-sensitive control logic. |
| Logic Compatibility | TTL-input compatible (VIH = 2 V, VIL = 0.8 V) - Interoperates seamlessly with 74LS, 74F, and other bipolar TTL families. |
Pinout & Package
SN74HCT157D is housed in a 16-pin SOIC (Small Outline Integrated Circuit) package with 1.27-mm pitch, JEDEC MS-012AC compliant, moisture sensitivity level 1, and RoHS-compliant NiPdAu lead finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (G) | Strobe Enable | Active-low global enable: all Y outputs high-impedance when G = high; data passes only when G = low. |
| 2 (A/B) | Data Source Select | Common select line: selects A-inputs (A/B = low) or B-inputs (A/B = high) for all four channels simultaneously. |
| 3 (1A) | Channel 1 Input A | First bit of source A; routed to pin 4 (1Y) when A/B = low and G = low. |
| 4 (1Y) | Channel 1 Output | Output of first 2:1 mux; reflects 1A or 1B depending on A/B and G states. |
| 5 (2A) | Channel 2 Input A | Second bit of source A; routed to pin 6 (2Y) under valid select/strobe conditions. |
| 6 (2Y) | Channel 2 Output | Output of second 2:1 mux; synchronized timing with 1Y, 3Y, and 4Y. |
| 7 (3A) | Channel 3 Input A | Third bit of source A; paired with 3B (pin 9) and controlled by same A/B/G logic. |
| 8 (3B) | Channel 3 Input B | Third bit of source B; alternative input for channel 3, selected when A/B = high. |
| 9 (4A) | Channel 4 Input A | Fourth bit of source A; connects to pin 10 (4Y) when A/B = low and G = low. |
| 10 (4Y) | Channel 4 Output | Final multiplexer output; completes 4-bit word routing capability. |
| 11 (2B) | Channel 2 Input B | Second bit of source B; selected for output at pin 6 when A/B = high. |
| 12 (GND) | Ground Reference | Primary return path for all internal logic and I/O; must be low-impedance for noise immunity. |
| 13 (3Y) | Channel 3 Output | Third output; matches timing and drive strength of other Y pins for coherent 4-bit transfer. |
| 14 (VCC) | Positive Supply | 5-V nominal supply input; decoupling capacitor (0.1 µF) required adjacent to pin for stable operation. |
| 15 (1B) | Channel 1 Input B | First bit of source B; selected for pin 4 output when A/B = high and G = low. |
| 16 (4B) | Channel 4 Input B | Fourth bit of source B; complements 4A (pin 9) to complete full 4-bit dual-source selection. |
Key Features
| Feature | Design Value |
|---|---|
| Quad 2:1 Multiplexing | Four independent 2-input selectors sharing one A/B control and one G strobe - reduces component count vs. discrete gate solutions. |
| TTL-Compatible Inputs | VIH = 2 V min and VIL = 0.8 V max - eliminates need for level translators when interfacing with legacy 74LS or 74F logic. |
| High-Current Outputs | ±6 mA drive at 5 V - directly interfaces with LSTTL loads without external drivers, simplifying board layout. |
| Low Static Power | ICC ≤ 80 µA max - enables use in always-on control logic where quiescent current impacts system battery life. |
| Buffered I/O | Internally buffered inputs and outputs - improves noise immunity and ensures clean signal edges across temperature range. |
Applications
| Industrial PLC I/O Expansion | Digital Test Equipment Signal Routing |
|---|---|
|
Use Scenario: Expanding discrete input channels in programmable logic controllers by selecting between primary sensor inputs and diagnostic test signals. IC Role / Device Role / Timing Role: Data selector enabling dynamic reconfiguration of 4-bit parallel input paths without FPGA or microcontroller intervention. Use Value: Reduces PCB footprint and firmware complexity versus software-controlled GPIO multiplexing; supports deterministic <15 ns path latency. |
Use Scenario: Switching between reference and DUT signals in automated test equipment for comparative waveform analysis. IC Role / Device Role / Timing Role: Synchronized 4-bit analog/digital signal path selector with simultaneous channel gating via G input. Use Value: Enables sub-20 ns switching between test modes while maintaining signal integrity across all four channels. |
| Legacy Bus Arbitration Interface | Microcontroller Peripheral Multiplexing |
|
Use Scenario: Arbitrating between two 4-bit peripheral buses (e.g., keypad matrix and status display) sharing a single MCU data port. IC Role / Device Role / Timing Role: Hardware-based bus selector that isolates conflicting peripherals using TTL-level control lines. Use Value: Eliminates software polling overhead and avoids bus contention faults; operates reliably across −40°C to +85°C industrial range. |
Use Scenario: Sharing limited GPIO pins between multiple sensors (e.g., temperature and humidity) on resource-constrained 8-bit MCUs. IC Role / Device Role / Timing Role: Parallel data selector allowing one MCU port to read two separate 4-bit sensor outputs via A/B control. Use Value: Doubles effective I/O capacity without increasing MCU pin count or requiring I²C/SPI bridge components. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad 2-line-to-1-line multiplexer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HC157D | Higher ICC (160 µA max), wider VCC range (2 V–6 V), no TTL input compatibility - requires ≥3.15 V VIH. | Suitable for 3.3-V systems but not direct drop-in for 5-V TTL-driven designs due to input threshold mismatch. | Choose SN74HC157D only if operating at 3.3 V or higher VCC tolerance is required and upstream logic is CMOS-compatible. |
| 74LVC157APW | 3.3-V optimized (1.65 V–3.6 V), ±24 mA drive, 3.5 ns tpd, no 5-V tolerance - incompatible with 5-V VCC or TTL inputs. | Designed for modern low-voltage portable electronics; cannot replace SN74HCT157D in 5-V industrial systems. | Select 74LVC157APW only for new 3.3-V designs prioritizing speed and drive strength over 5-V interoperability. |
Compared with SN74HCT157D, SN74HC157D offers broader voltage flexibility but lacks TTL input compatibility, while 74LVC157APW delivers superior speed and drive in 3.3-V domains but is electrically incompatible with 5-V operation - making SN74HCT157D uniquely suited for legacy 5-V TTL-interfaced systems requiring guaranteed 2-V VIH.
Availability
SN74HCT157D is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, digital test equipment signal routing, and legacy bus arbitration requiring stable component supply and long-term obsolescence management.
Supply support for SN74HCT157D 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 founded in 1930, specializing in analog, embedded processing, and logic solutions with broad industrial, automotive, and communications portfolio coverage.
The SN74HCT157D belongs to TI's 74HCT logic family, engineered specifically for seamless 5-V TTL-to-CMOS interfacing in industrial control, instrumentation, and legacy system upgrades.
FAQ
What is the function of the G (strobe) pin on the SN74HCT157D?
The G pin on the SN74HCT157D is an active-low strobe enable that globally controls output state: when G is high, all four Y outputs enter high-impedance mode regardless of A/B or input states; when G is low, the selected A or B inputs pass through to corresponding Y outputs. This allows time-multiplexed data routing or bus isolation without affecting upstream logic. The SN74HCT157D uses this feature to prevent bus contention in shared-data-path applications.
Can SN74HCT157D operate at 3.3 V?
No, the SN74HCT157D is not rated for 3.3-V operation. Its recommended operating voltage is strictly 4.5 V to 5.5 V, and its TTL-compatible input thresholds (VIH = 2 V min, VIL = 0.8 V max) assume a 5-V supply context. Operating below 4.5 V risks incorrect logic interpretation, increased propagation delay, and potential failure to meet output drive specifications. For 3.3-V systems, consider SN74LVC157A instead - but note it is not a pin-compatible replacement for SN74HCT157D.
What does "TTL-compatible inputs" mean for SN74HCT157D?
"TTL-compatible inputs" means the SN74HCT157D accepts standard TTL voltage levels as valid logic signals: VIH ≥ 2.0 V guarantees recognition as HIGH, and VIL ≤ 0.8 V guarantees recognition as LOW - matching 74LS and 74F families. This eliminates need for external level shifters when driving the SN74HCT157D from legacy TTL outputs, preserving signal integrity and timing margins. The SN74HCT157D achieves this while consuming CMOS-level static power.
Is SN74HCT157D pin-compatible with SN74LS157N?
Yes, the SN74HCT157D is pin-compatible with SN74LS157N in SOIC-16 (D) and PDIP-16 (N) packages respectively, sharing identical pin numbering and functional assignment (G, A/B, 1A–4B, 1Y–4Y, VCC, GND). However, SN74HCT157D offers lower power consumption (80 µA vs. ~15 mA ICC), higher noise immunity, and CMOS output structure - making it a direct functional upgrade in existing 74LS157 layouts without PCB changes, provided VCC remains 5 V ±5%.
What is the maximum capacitive load the SN74HCT157D can drive while maintaining specified tpd?
The SN74HCT157D's specified propagation delay (tpd = 15 ns typ) is guaranteed with CL = 50 pF, per the datasheet switching characteristics table. At CL = 150 pF, tpd increases to 19 ns (typ) at 5.5 V. While the device can drive heavier loads, exceeding 150 pF significantly degrades edge rate and timing margin - for reliable operation within datasheet limits, keep total load (including trace capacitance and input capacitance of downstream devices) ≤50 pF for 15 ns performance, or ≤150 pF for ≤19 ns. The SN74HCT157D's ±6-mA drive supports such loads without external buffering.
SN74HCT157D Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Type:
- Multiplexer
- Circuit:
- 4 x 2:1
- Independent Circuits:
- 1
- Current - Output High, Low:
- 6mA, 6mA
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SN74HCT157D FAQ
1.How can I place an order for SN74HCT157D through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT157D 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 SN74HCT157D reliable?
The price and inventory of SN74HCT157D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT157D is usually 5 days.
3.What payment methods are accepted for SN74HCT157D?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HCT157D transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HCT157D?
SN74HCT157D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCT157D 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 SN74HCT157D?
For technical support, including SN74HCT157D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT157D requirements.
6.How does Aetrix verify that SN74HCT157D is sourced from the original manufacturer or authorized distributors?
All SN74HCT157D 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 SN74HCT157D meets industry standards.
7.What is the process for return or replacement of SN74HCT157D?
All SN74HCT157D units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT157D, 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 SN74HCT157D part is unused and in its original packaging.
Return procedure for SN74HCT157D:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74HCT157D Tags
-
SN74HC138DR
Texas Instruments
-
TC7SB3157CFU,LF(CT
Toshiba Semiconductor and Storage
-
74CBTLV3257PW,118
Nexperia USA Inc.
-
SN74CBTLV3257PWR
Texas Instruments
-
74CBTLV3257GUX
Nexperia USA Inc.
-
74HC154BQ,118
Nexperia USA Inc.
-
P3S0200GMX
NXP USA Inc.
-
SN74CB3Q3245PWR
Texas Instruments
-
SN74CB3Q3257RGYR
Texas Instruments
-
TCA9543APWR
Texas Instruments
-
TCA9546APWR
Texas Instruments
-
SN74HC138N
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
