Texas Instruments SN74HC273PW

Overview

SN74HC273PW from Texas Instruments is an octal positive-edge-triggered D-type flip-flop with active-low asynchronous clear, operating from 2 V to 6 V supply, delivering 12 ns typical propagation delay at 5 V, ±4 mA output drive, and 80 µA maximum ICC - used for synchronous data latching in digital control registers and interface buffering.

For engineers reviewing the SN74HC273PW datasheet, SN74HC273PW pinout, SN74HC273PW application, or SN74HC273PW equivalent, key selection criteria include its TSSOP-20 package, single-rail outputs, direct clear functionality, and compatibility with LSTTL loads in industrial logic systems requiring deterministic edge-triggered storage.

Technical Context

The SN74HC273PW implements eight independent D flip-flops sharing a common clock (CLK) and global active-low clear (CLR), with each D input directly controlling its corresponding Q output on the rising edge of CLK. All inputs are CMOS-compatible with VIH/VIL thresholds scaling with VCC.

It operates across –40°C to +85°C, supports 21 MHz max clock frequency at 4.5 V, and features low input current (≤1 µA) and low power dissipation (Cpd = 35 pF per flip-flop), making it suitable for battery-aware and noise-sensitive logic interfacing where rail-to-rail signal integrity is required.

Key Specifications

Pinout & Package

TSSOP-20 package (6.50 mm × 4.40 mm), 0.65 mm lead pitch, RoHS-compliant, moisture sensitivity level 1 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal D-type flip-flop applications.

Compared with SN74HC374PW and 74ACT273PW, SN74HC273PW uniquely balances wide supply range (2–6 V), ultra-low static current (80 µA), and deterministic non-tristate output behavior - making it optimal for cost-sensitive, power-constrained industrial register applications where bus contention is absent.

Availability

SN74HC273PW is available at Aetrix Electronics and suitable for industrial PLC I/O modules, microcontroller GPIO expansion, test equipment pattern generation, and legacy bus interface buffering requiring stable component supply and long-term lifecycle support.

Supply support for SN74HC273PW 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 expertise in high-reliability logic families.

The SN74HC273PW belongs to TI's HC (High-Speed CMOS) logic series, designed for industrial and commercial applications demanding low power, wide voltage operation, and robust noise immunity in digital control and interface circuits.

FAQ

What is the function of the CLR pin on the SN74HC273PW?

The CLR (clear) pin on the SN74HC273PW is an active-low asynchronous input that forces all eight Q outputs low immediately, independent of the clock signal. When asserted (pulled to GND), it overrides any stored data and resets the register. It must be held high (≥VCC – 0.2 V) during normal operation to allow clocked data transfer. The minimum pulse width is 20 ns at 4.5 V, as specified in the SN74HC273PW timing requirements.

Does the SN74HC273PW support 3.3 V operation?

Yes, the SN74HC273PW fully supports 3.3 V operation within its rated supply range of 2 V to 6 V. At VCC = 3.3 V, it maintains valid VIH (≥2.31 V) and VIL (≤0.99 V) thresholds, delivers ≥2 mA output drive, and achieves typical tpd of ~15 ns (per interpolation from datasheet curves). Its CMOS inputs draw <1 µA, making it compatible with 3.3 V microcontrollers without level shifting.

Can unused inputs on the SN74HC273PW be left floating?

No, unused inputs on the SN74HC273PW must never be left floating. CMOS inputs have high impedance and undefined voltage states when unconnected, which can cause excessive ICC, oscillation, or erratic output behavior. All unused D inputs and the CLR pin must be tied to either VCC or GND using ≤10 kΩ resistors. TI explicitly recommends this in Application Report "Implications of Slow or Floating CMOS Inputs" to ensure stable SN74HC273PW operation.

What is the maximum clock frequency for the SN74HC273PW at 5 V?

At VCC = 5 V (within 4.5 V–6 V range), the SN74HC273PW supports a maximum clock frequency of 21 MHz under full temperature range (–40°C to +85°C), as specified in Section 6.10 of the datasheet. At 25°C, typical fmax reaches 50 MHz. This limit is determined by propagation delay (tpd ≤ 40 ns max), setup time (tsu ≥ 25 ns), and pulse width constraints - all verified per JEDEC JESD78 reliability testing for the SN74HC273PW.

Is the SN74HC273PW pin-compatible with other TSSOP-20 logic devices?

The SN74HC273PW uses standard TSSOP-20 mechanical dimensions (6.50 mm × 4.40 mm, 0.65 mm pitch) and follows JEDEC MO-153, but pin compatibility is function-specific. While physical footprint matches SN74HC374PW and SN74HC574PW, their pinouts differ - e.g., SN74HC374PW places OE on Pin 1 while SN74HC273PW uses Pin 1 for CLR. Therefore, SN74HC273PW is not pin-compatible with other octal D flip-flops; PCB layout must match its unique pin mapping per Table 5-1.