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STMicroelectronics M74HCT125TTR
- Part No.:
- M74HCT125TTR
- Manufacturer:
- STMicroelectronics
- Package:
- 14-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
M74HCT125TTR.pdf
- Description:
- IC BUF NON-INVERT 5.5V 14TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,434
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Product details
Overview
M74HCT125TTR from STMicroelectronics is a high-speed CMOS quad 3-state bus buffer with TTL-compatible inputs, 13 ns typical propagation delay at 4.5 V, ±6 mA symmetrical output drive, and 4 µA max quiescent current at 25°C - used for bidirectional data bus isolation in industrial control backplanes and legacy microprocessor system expansion interfaces.
For engineers reviewing the M74HCT125TTR datasheet, M74HCT125TTR pinout, M74HCT125TTR application, or M74HCT125TTR equivalent, key selection criteria include 3-state enable timing (tPZL/tPLZ ≤ 36 ns), input voltage thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V), rail-to-rail output swing under 6 mA load, and TSSOP-14 thermal derating above 65°C.
Technical Context
The M74HCT125TTR implements four independent non-inverting buffers, each with a dedicated active-low 3-state enable input (G1–G4), enabling selective bus driving without contention. Its C2MOS silicon gate process ensures TTL-level input compatibility while maintaining CMOS power efficiency.
Propagation delays are balanced (tPLH ≅ tPHL) and output impedance is symmetrical (|IOH| = IOL ≥ 6 mA), supporting clean signal integrity on shared data buses. All inputs include integrated ESD protection diodes rated for ±20 mA transient current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Propagation Delay | 13 ns typ. at VCC = 4.5 V, CL = 50 pF - enables reliable operation up to ~30 MHz bus clocking |
| Output Drive | ±6 mA min. - sustains logic levels under standard TTL fan-out loading (10 LS-TTL loads) |
| Input Thresholds | VIH ≥ 2.0 V, VIL ≤ 0.8 V - ensures robust interfacing with 5 V TTL and NMOS logic families |
| Quiescent Current | 4 µA max. at TA = 25°C - supports low-static-power system standby modes |
| Operating Voltage | 4.5–5.5 V - compatible with regulated 5 V supply rails and tolerates nominal 5 % ripple |
| Temperature Range | −55°C to +125°C - qualified for extended industrial and automotive under-hood environments |
| ESD Protection | ±20 mA DC input diode current rating - withstands common handling and board-level transients |
Pinout & Package
TSSOP-14 package: 4.9 × 6.4 mm body, 0.65 mm pitch, 1.2 mm max height, exposed pad not present, JEDEC MO-153 compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 10, 13 | G1–G4 (Active-High Enable) | Assert high to disable output (high-Z); critical for bus arbitration timing |
| 2, 5, 9, 12 | A1–A4 (Data Inputs) | TTL-compatible inputs; accept 0–5 V swing with 2 V/0.8 V thresholds |
| 3, 6, 8, 11 | Y1–Y4 (Data Outputs) | Non-inverting buffered outputs; drive ±6 mA into resistive or capacitive loads |
| 7 | GND | Reference ground for all I/O and internal logic; requires low-impedance PCB connection |
| 14 | VCC | Positive supply (4.5–5.5 V); decoupling capacitor (100 nF) required within 5 mm |
Key Features
| Feature | Design Value |
|---|---|
| Balanced propagation delays | tPLH ≅ tPHL ensures minimal duty-cycle distortion on clocked data paths |
| Symmetrical output impedance | |IOH| = IOL ≥ 6 mA guarantees matched rise/fall times under load |
| 3-state enable timing control | tPZL/tPLZ ≤ 36 ns (−55°C to +125°C) enables precise bus turnaround sequencing |
| Input ESD protection | Integrated diodes rated ±20 mA - eliminates need for external clamping on board-level I/O |
| PIN- and FUNCTION-compatible with 74LS125 | Direct drop-in replacement for legacy TTL bus buffers without layout change |
Applications
| Industrial PLC Backplane Interface | Legacy Microprocessor System Expansion |
|---|---|
Use Scenario: Isolating address/data buses between CPU module and I/O carrier card in modular PLC chassis. IC Role / Device Role / Timing Role: Quad 3-state buffer managing bidirectional 8-bit data transfer with cycle-synchronized enable control. Use Value: Prevents bus contention during DMA transfers; 13 ns delay allows full utilization of 20 MHz Z80/8086 bus cycles. | Use Scenario: Adding peripheral slots to vintage 8-bit computer systems using ISA-like bus architecture. IC Role / Device Role / Timing Role: Level-shifting and fan-out buffering between TTL peripherals and CMOS-based address latch logic. Use Value: VIH/VIL thresholds ensure noise-immune recognition of TTL signals; 4 µA ICC supports low-power sleep states. |
| Automotive Body Control Module | Test Equipment Signal Routing |
Use Scenario: Multiplexing sensor readouts (LIN, analog switches) onto shared diagnostic bus in BCM subassembly. IC Role / Device Role / Timing Role: Enabling/disabling sensor data lanes under microcontroller GPIO control. Use Value: −55°C to +125°C rating meets AEC-Q100 Grade 1 requirements; symmetrical drive avoids skew in multi-sensor sampling. | Use Scenario: Reconfigurable signal path switching in automated test fixtures for mixed-signal PCB validation. IC Role / Device Role / Timing Role: Electrically isolating DUT I/O channels during functional test sequence transitions. Use Value: 3-state timing (tPZL/tPLZ ≤ 36 ns) enables <100 ns channel switching; TSSOP-14 footprint saves fixture board space. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad 3-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT125PW | TSSOP-14, identical AC/DC specs, TI's characterization across −40°C to +85°C only | Limited temperature range vs. M74HCT125TTR's −55°C to +125°C qualification | Select when full industrial temp range is not required and TI supply chain preference applies |
| 74VHC125FT | TSSOP-14, higher VCC range (2–5.5 V), lower ICC (2 µA typ.), but VOH/VOL degraded at 6 mA load | Lower drive strength (4 mA typ.) limits fan-out in TTL-interfaced systems | Prefer for battery-powered systems needing ultra-low ICC, not for TTL bus driving |
Compared with SN74HCT125PW and 74VHC125FT, the M74HCT125TTR uniquely combines full −55°C to +125°C operation, guaranteed ±6 mA drive, and direct 74LS125 pin/function compatibility - making it optimal for legacy-replacement and extended-temperature embedded control.
Availability
M74HCT125TTR is available at Aetrix Electronics and suitable for industrial PLC backplane interfaces, automotive body control modules, and legacy microprocessor system expansion requiring stable component supply over extended lifecycle.
Supply support for M74HCT125TTR 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, digital, and mixed-signal ICs for industrial, automotive, and consumer markets.
The M74HCT125TTR belongs to ST's HCT logic family - engineered for seamless TTL-to-CMOS interfacing in high-reliability, extended-temperature embedded systems.
FAQ
Is M74HCT125TTR pin-compatible with 74LS125?
Yes - M74HCT125TTR has identical pinout and function mapping to 74LS125: pins 1/4/10/13 are active-high enables, pins 2/5/9/12 are inputs, and pins 3/6/8/11 are outputs. No PCB redesign is needed for drop-in replacement in existing 74LS125 layouts.
What is the maximum capacitive load this device can drive reliably?
The M74HCT125TTR is characterized up to 150 pF (AC specs tested at CL = 50 pF and 150 pF). With tPLH/tPHL ≤ 41 ns and output transition time ≤ 18 ns at 150 pF, it reliably drives standard PCB traces and multiple LS-TTL inputs without signal degradation.
Does M74HCT125TTR require external pull-up or pull-down resistors on enable inputs?
No - the G inputs have no internal pull resistors, but their TTL-compatible thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) allow direct connection to CMOS logic outputs or microcontroller GPIOs. External biasing is only needed if floating states must be avoided in unpowered or undefined-control scenarios.
Can M74HCT125TTR operate from a 3.3 V supply?
No - the recommended VCC range is strictly 4.5 V to 5.5 V per datasheet Section 2. Operating below 4.5 V violates AC/DC specifications: VOH drops below 2.4 V at 6 mA load, and VIH minimum (2.0 V) becomes marginal relative to VCC, risking unreliable logic recognition.
M74HCT125TTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- 74HCT
- Package/Case:
- 14-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Logic Type:
- Buffer, Non-Inverting
- Number of Elements:
- 4
- Number of Bits per Element:
- 1
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 6mA, 6mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-TSSOP
M74HCT125TTR FAQ
1.How can I place an order for M74HCT125TTR through Aetrix?
Please submit a Request for Quotation (RFQ) for M74HCT125TTR 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 M74HCT125TTR reliable?
The price and inventory of M74HCT125TTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M74HCT125TTR is usually 5 days.
3.What payment methods are accepted for M74HCT125TTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M74HCT125TTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for M74HCT125TTR?
M74HCT125TTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your M74HCT125TTR 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 M74HCT125TTR?
For technical support, including M74HCT125TTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M74HCT125TTR requirements.
6.How does Aetrix verify that M74HCT125TTR is sourced from the original manufacturer or authorized distributors?
All M74HCT125TTR 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 M74HCT125TTR meets industry standards.
7.What is the process for return or replacement of M74HCT125TTR?
All M74HCT125TTR units undergo pre-shipment inspection (PSI). If there is an issue with M74HCT125TTR, 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 M74HCT125TTR part is unused and in its original packaging.
Return procedure for M74HCT125TTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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