M74HCT273B1R - 8-Bit D-Type Flip-Flop with Clear, DIP-20 | STMicroelectronics
N.º de pieza: M74HCT273B1R ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $0.62 | $0,62 |
| 10 | $0.54 | $5,40 |
| 100 | $0.41 | $41,00 |
| 500 | $0.32 | $160,00 |
| 1.000 | $0.27 | $270,00 |
M74HCT273B1R Descripción general
An octal D-type flip-flop is a synchronous digital storage element which captures logic levels on eight parallel D inputs at the rising edge of a common clock and holds them on eight Q outputs. The 74HCT family combines low-power high-speed CMOS logic with TTL-compatible input thresholds (VIH = 2.0 V minimum), allowing direct interface with 5 V TTL buses without level shifters. The M74HCT273B1R sits in the digital logic IC hierarchy as: flip-flop -> sequential logic -> logic IC -> integrated circuit -> discrete semiconductor category. Its single-bit-wide clocked register function makes it a foundational building block in bus-oriented digital systems.
Key features include a common clock and common master reset (active-low CLR) shared by all eight latches, non-inverted Q outputs, complementary CMOS output drive, low quiescent current of 4 uA, and broad compatibility with 74LS273 and 74HCT273 logic families from multiple vendors. The 20-pin PDIP package retains through-hole compatibility with legacy breadboard and socketed designs, while the HCT input stage directly accepts bipolar TTL drive levels.
Technically, the device uses high-performance silicon-gate CMOS to deliver fMAX = 80 MHz (typical) at 4.5 V supply with tPLH around 13 ns and tPHL around 17 ns, all while drawing only a few microamperes of quiescent current. The master reset overrides the clock and asynchronously forces all Q outputs low when driven low.
Typical applications include address and data latching in microcontroller expansion logic, I/O port expansion with 74HC595-style shift chains (this part is parallel-load, not serial-shift), debounced pushbutton and rotary-synchronous address, and general-purpose register buffering in TTL-based industrial control and instrumentation systems.
When designing with this part, ensure the CLR pin is tied high through a pull-up resistor if asynchronous reset is not used, and provide standard 0.1 uF decoupling close to VCC to maintain noise margin in mixed-signal environments.
This page synthesizes distributor pricing, drop-in alternatives, and design guidance beyond the manufacturer datasheet alone.
Alternativas directas para M74HCT273B1R — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
M74HCT273B1N
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
SN74HCT273N
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
CD74HCT273E
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MM74HCT273N
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MC74HCT273AN
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
74HCT273N
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
M74HCT273B1R Valores máximos y características eléctricas
| Función | Octal D-Type Flip-Flop with Clear |
| Logic Family | 74HCT (High-Speed CMOS, TTL-compatible inputs) |
| Number of Elements | 1 |
| Bits per Element | 8 |
| Trigger Type | Positive Edge |
| Tipo de salida | Non-Inverted |
| Supply Voltage (VCC) | 4.5 V to 5.5 V |
| Input Voltage Threshold VIH | 2.0 V minimum (TTL-compatible) |
| Maximum Clock Frequency fMAX | 80 MHz typical at VCC = 4.5 V |
| Maximum Propagation Delay | 30 ns |
| Quiescent Current (ICC) | 4 uA typical |
| Master Reset (CLR) | Yes, common asynchronous active-low reset |
| Rango de temperatura de funcionamiento | -55C to +125C |
| Encapsulado | 20-DIP (0.300 inch, 7.62 mm) |
| Tipo de montaje | Through-Hole |
Configuración de pines de M74HCT273B1R
| Pin 1 | CLR — Master Reset (active low, asynchronous) |
| Pin 2 | Q0 — Output Q0 |
| Pin 3 | D0 — Data input D0 |
| Pin 4 | D1 — Data input D1 |
| Pin 5 | Q1 — Output Q1 |
| Pin 6 | D2 — Data input D2 |
| Pin 7 | Q2 — Output Q2 |
| Pin 8 | D3 — Data input D3 |
| Pin 9 | Q3 — Output Q3 |
| Pin 10 | GND — Ground |
| Pin 11 | CLK — Clock input (positive edge trigger) |
| Pin 12 | Q4 — Output Q4 |
| Pin 13 | D4 — Data input D4 |
| Pin 14 | D5 — Data input D5 |
| Pin 15 | Q5 — Output Q5 |
| Pin 16 | D6 — Data input D6 |
| Pin 17 | Q6 — Output Q6 |
| Pin 18 | D7 — Data input D7 |
| Pin 19 | Q7 — Output Q7 |
| Pin 20 | VCC — Positive supply voltage (4.5 V to 5.5 V) |
Aplicaciones típicas
M74HCT273B1R es adecuado para 7 aplicacións: Microcontroller Address/Data Latching, Parallel I/O Port Expansion, Debounced Pushbutton and Rotary Encoder Input Register, Industrial Control and Instrumentation Registers, Legacy TTL System Replacement, Glue Logic in Mixed-Signal Systems, Educational / Breadboard Prototyping of Sequential Logic.
Microcontroller Address/Data Latching
The M74HCT273B1R's eight edge-triggered D flip-flops latch address or data bus bits from a microcontroller's parallel port on each rising clock edge, holding them stable for downstream logic until the next update. Its 4.5-5.5 V supply and TTL-compatible inputs (VIH = 2.0 V minimum) directly accept 5 V MCU GPIO drive without level shifting. The 80 MHz typical clock rate handles fast register-update cycles, while the common asynchronous CLR pin enables rapid system-wide reset when needed. In 8051-style address-latching designs it captures the low-byte address from the multiplexed AD bus during ALE, freeing the bus for data transfers.
Recomendado
Parallel I/O Port Expansion
Use the M74HCT273B1R as an output port expander that captures 8 bits from a microcontroller's data bus on a clock edge and holds them on the Q outputs to drive relays, LEDs, or higher-current buffers. Its 20-pin PDIP package and through-hole mounting make it ideal for breadboard prototyping of expanded GPIO channels. The 30 ns maximum propagation delay suits moderate-speed control loops such as driving stepper motor drivers or solenoid banks. The HCT input stage accepts direct 5 V TTL drive from common MCU families without external level shifters.
Recomendado
Debounced Pushbutton and Rotary Encoder Input Register
The M74HCT273B1R captures parallel button or encoder inputs at a debounce-clock rate and presents a clean synchronized word to the host controller, isolating mechanical bounce from software. Its 4 uA quiescent current makes it suitable for battery-powered or always-on monitoring circuits. The common clock and common reset simplify synchronizing an 8-bit input vector on a single interrupt. The 5 V TTL-compatible inputs interface directly with CMOS sensor or switch-matrix networks in industrial user-interface panels.
Recomendado
Industrial Control and Instrumentation Registers
The M74HCT273B1R operates reliably from -55C to +125C, making it suitable for industrial control, instrumentation, and process-control front-ends where temperature swings are common. Its HCT logic family tolerates the noisy 5 V rails typical of factory floor PLC backplanes and provides a stable register stage between sensor conditioning circuits and a control MCU. The 80 MHz typical fMAX ensures status registers can update quickly enough for high-speed data-acquisition front-ends, while the master CLR pin supports emergency-shutdown latching.
Recomendado
Legacy TTL System Replacement
The M74HCT273B1R is a direct replacement for obsolete 74LS273, 74S273, or 74F273 octal D flip-flops in legacy 5 V TTL designs, preserving the original PCB footprint (20-pin PDIP) while reducing power consumption through CMOS HCT technology. Its TTL-compatible input thresholds (VIH = 2.0 V minimum) ensure it interoperates correctly with remaining bipolar TTL drivers in mixed-vintage systems. The 4 uA quiescent current versus bipolar LS-series 10-20 mA reduces board-level power draw and heat in retrofitted industrial systems.
Recomendado
Glue Logic in Mixed-Signal Systems
The M74HCT273B1R serves as glue logic between analog front-ends, ADC/DAC channels, and digital controllers, capturing configuration or status bytes on the rising edge of a strobe signal. Its 30 ns propagation delay is fast enough for most 1 MHz-class data-acquisition bus cycles. The 5 V TTL-compatible inputs interface directly to 5 V CMOS and bipolar logic on the same board without level shifting. The common reset supports software-initiated calibration cycles by clearing all eight latched values simultaneously.
Recomendado
Educational / Breadboard Prototyping of Sequential Logic
The M74HCT273B1R's 20-pin PDIP through-hole package makes it ideal for breadboard prototyping of sequential-logic and state-machine coursework. Students can manually clock the device with a pushbutton or 555 timer and observe the eight Q outputs on LEDs to learn edge-triggered storage, asynchronous reset behavior, and TTL-to-CMOS interfacing. The HCT input stage accepts any 5 V signal source (TTL, CMOS, MCU GPIO) without level conversion, simplifying classroom lab setups.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para M74HCT273B1R — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | M74HCT273B1N | SN74HCT273N | CD74HCT273E | MM74HCT273N | MC74HCT273AN | 74HCT273N |
|---|---|---|---|---|---|---|---|
| Brand | STMicroelectronics | STMicroelectronics | Texas Instruments | Texas Instruments | onsemi | onsemi | Nexperia |
| Package | PDIP-20 (0.300 inch) | PDIP-20 - same | PDIP-20 - same | PDIP-20 - same | PDIP-20 - same | PDIP-20 - same | PDIP-20 - same |
| Supply Voltage (VCC) | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V |
| Maximum Clock Frequency | 80 MHz typical | 80 MHz typical | 50 MHz typical | 60 MHz typical | 80 MHz typical | 30 MHz typical | 78 MHz typical |
| Propagation Delay tPD | 30 ns max | 30 ns max | 25 ns max | 22 ns max | 30 ns max | 30 ns max | 30 ns max |
| Quiescent Current (ICC) | 4 uA typical | 4 uA typical | 8 uA typical | 8 uA typical | 4 uA typical | 4 uA typical | 4 uA typical |
| Master Reset (CLR) | Yes, active-low async | Yes, active-low async | Yes, active-low async | Yes, active-low async | Yes, active-low async | Yes, active-low async | Yes, active-low async |
| Operating Temperature Range | -55C to +125C | -55C to +125C | -40C to +85C | -55C to +125C | -40C to +85C | -55C to +125C | -40C to +125C |
Diferenciadores clave
- ST brand with extended -55C to +125C operating range (frente a SN74HCT273N)
- Lower quiescent current than TI SN74HCT273N (frente a SN74HCT273N)
- Higher maximum clock frequency than TI CD74HCT273E (frente a CD74HCT273E)
Notas de diseño
The M74HCT273B1R draws only 4 uA quiescent current but can source or sink up to 4 mA per output. Total VCC current scales with switching frequency and load capacitance - estimate ICC total = ICC_quiescent + (C_L * VCC * f * N_outputs) where C_L is load capacitance, f is clock frequency, and N_outputs is the number of switching outputs. At 80 MHz clocking eight outputs into 50 pF loads, dynamic current can reach 8-10 mA. Always include a 0.1 uF decoupling capacitor close to VCC pin 20, plus a bulk 1-10 uF tantalum or ceramic on the 5 V rail.
The CLR pin is asynchronous active-low - if left floating it can pick up noise and cause spurious resets. Always tie CLR high through a 10 kohm pull-up resistor if asynchronous reset is not actively driven. Do not drive CLR below 0 V or above VCC. When using CLR to reset on power-up, ensure the CLR pulse width exceeds tW_CLR = 20 ns minimum to reliably clear all eight latches per datasheet timing.
Place the M74HCT273B1R on the same 5 V power plane as the driving logic to minimize ground bounce. Keep clock (pin 11) traces short and routed away from output traces to avoid capacitive coupling of clock edges into Q transitions. The 20-pin PDIP through-hole footprint requires standard 0.300 inch row spacing with 0.100 inch pin pitch - verify socket or PCB layout matches this footprint, especially when substituting the SOIC-20 SN74HCT273D variant which is not drop-in compatible.
Estimate: At a 30 ns propagation delay with 8 outputs switching simultaneously into 50 pF loads, ground-bounce voltage can reach V = L * di/dt where L is package lead inductance (~5 nH for PDIP) and di/dt = (4 mA) / (2 ns edge rate) = 2 A/us. This yields roughly 10 mV ground bounce - normally tolerable for TTL-level noise margin (~400 mV) but can couple into adjacent analog circuitry. Add a small ferrite bead on VCC near the IC if adjacent analog signals are sensitive.
Información de cumplimiento
RoHS, REACH, lead-free, halogen-free, and conflict-mineral compliance status were not present in the Verified Web Data and are marked unknown. AEC-Q100 not applicable for a through-hole HCT logic IC.
