M74HCT273B1R - 8-Bit D-Type Flip-Flop with Clear, DIP-20 | STMicroelectronics
MPN: M74HCT273B1R ✓ Hoạt độngM74HCT273B1R Tóm tắt
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.
Bộ thay thế dễ dàng lắp đặt cho M74HCT273B1R — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
M74HCT273B1N
✅ Drop-In ⚠️ Thông số chưa được xác minh📋 Tham chiếu thay thế (không có trong danh mục)
SN74HCT273N
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
CD74HCT273E
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MM74HCT273N
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
MC74HCT273AN
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
74HCT273N
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
M74HCT273B1R Tỷ lệ tối đa & tính chất điện
| Chức năng | 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 |
| Kiểu đầu ra | 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 |
| Khoảng nhiệt độ hoạt động | -55C to +125C |
| Hộp | 20-DIP (0.300 inch, 7.62 mm) |
| Kiểu lắp đặt | Through-Hole |
Cấu hình chân M74HCT273B1R
| Chân 1 | CLR — Master Reset (active low, asynchronous) |
| Chân 2 | Q0 — Output Q0 |
| Chân 3 | D0 — Data input D0 |
| Chân 4 | D1 — Data input D1 |
| Chân 5 | Q1 — Output Q1 |
| Chân 6 | D2 — Data input D2 |
| Chân 7 | Q2 — Output Q2 |
| Chân 8 | D3 — Data input D3 |
| Chân 9 | Q3 — Output Q3 |
| Chân 10 | GND — Ground |
| Chân 11 | CLK — Clock input (positive edge trigger) |
| Chân 12 | Q4 — Output Q4 |
| Chân 13 | D4 — Data input D4 |
| Chân 14 | D5 — Data input D5 |
| Chân 15 | Q5 — Output Q5 |
| Chân 16 | D6 — Data input D6 |
| Chân 17 | Q6 — Output Q6 |
| Chân 18 | D7 — Data input D7 |
| Chân 19 | Q7 — Output Q7 |
| Chân 20 | VCC — Positive supply voltage (4.5 V to 5.5 V) |
Ứng dụng tiêu biểu
M74HCT273B1R phù hợp cho 7 Áp dụngs: 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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho M74HCT273B1R — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | 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 |
Bảo phân biệt quan trọng
- ST brand with extended -55C to +125C operating range (vsSN74HCT273N)
- Lower quiescent current than TI SN74HCT273N (vsSN74HCT273N)
- Higher maximum clock frequency than TI CD74HCT273E (vsCD74HCT273E)
Ghi chú thiết kế
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.
Thông tin tuân thủ
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.
