Texas Instruments SN74HCS72PWR

Overview

SN74HCS72PWR from Texas Instruments is a dual D-type negative-edge-triggered flip-flop with Schmitt-trigger inputs, asynchronous clear and preset, operating from 2 V to 6 V. It delivers ±7.8-mA output drive at 5 V, consumes only 100 nA typical supply current, and supports operation from –40°C to +125°C. It is used in CAN wake-up power enable circuits where noise immunity and low-power state retention are critical.

For engineers reviewing the SN74HCS72PWR datasheet, SN74HCS72PWR pinout, SN74HCS72PWR application, or SN74HCS72PWR equivalent, key selection considerations include its Schmitt-trigger input hysteresis (ΔVT = 0.6–1.6 V), dual-channel independent operation, TSSOP-14 package footprint, and compatibility with slow/noisy edge-rate signals in automotive standby systems.

Technical Context

The SN74HCS72PWR implements two independent CMOS D-type flip-flops, each triggered on the falling edge of CLK. All inputs-D, CLK, PRE, and CLR-feature Schmitt-trigger architecture with defined VT+ (1.7–4.2 V) and VT− (0.9–3.0 V) thresholds across 4.5–6 V supply, enabling robust operation with slow or noisy waveforms.

Its functional modes are fully asynchronous for PRE/CLR (active-low), while data transfer occurs only on CLK's negative transition when both PRE and CLR are high. Output drive strength (±7.8 mA at 6 V) and low ICC (≤2 µA max) support direct interfacing with downstream logic and ultra-low-power system states without external buffering.

Key Specifications

Pinout & Package

TSSOP-14 package (5.00 mm × 4.40 mm), 1.2-mm height, lead-free (NIPDAU/Sn), MSL Level-1, RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCS72DR, the SN74HCS72PWR offers 29% smaller PCB area and better high-temperature performance due to lower junction-to-ambient resistance; versus MC74HC72DTG, it provides nearly double the output current for driving heavier logic loads or small MOSFET gates directly.

Availability

SN74HCS72PWR is available at Aetrix Electronics and suitable for automotive CAN subsystems, industrial sensor interfaces, momentary switch conditioning, and low-power standby controllers requiring stable component supply across extended temperature ranges.

Supply support for SN74HCS72PWR 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 company specializing in analog, embedded processing, and logic ICs, with leadership in automotive, industrial, and power management solutions.

The SN74HCS72PWR belongs to TI's HCS logic family-designed specifically for ultra-low-power, noise-immune digital interfacing in harsh environments where reliability and standby efficiency are paramount.

FAQ

What is the maximum clock frequency supported by the SN74HCS72PWR?

The SN74HCS72PWR supports a maximum switching frequency of 105 MHz at 6 V supply, 95 MHz at 4.5 V, and 31 MHz at 2 V, as specified in the Switching Characteristics table. These values assume CL = 50 pF and operation within recommended conditions. At 5 V nominal, typical fmax is ~90 MHz. The SN74HCS72PWR achieves this performance while maintaining sub-µA quiescent current, making it suitable for high-speed yet power-sensitive applications.

Does the SN74HCS72PWR require external pull-up or pull-down resistors on unused inputs?

Yes, unused inputs on the SN74HCS72PWR must be tied to VCC or GND-never left floating-to prevent undefined logic states and increased ICC. TI's layout guidelines explicitly require biasing all unused inputs, especially because Schmitt-trigger inputs have high impedance and can oscillate or draw excess current if unterminated. For example, an unused 2D input should connect to VCC or GND depending on desired default state; the SN74HCS72PWR datasheet confirms this in Section 11.1.

Can the SN74HCS72PWR operate with a 1.8-V supply?

No, the SN74HCS72PWR is not rated for 1.8-V operation. Its recommended operating supply voltage range is strictly 2 V to 6 V, with absolute maximum ratings from –0.5 V to 7 V. Operation below 2 V violates the Recommended Operating Conditions and may result in unreliable output levels, increased propagation delay variation, or failure to meet setup/hold timing. For 1.8-V systems, consider TI's SN74LVC1G74 or compatible LVC-family devices instead of the SN74HCS72PWR.

How does the Schmitt-trigger input hysteresis of the SN74HCS72PWR improve noise immunity?

The SN74HCS72PWR provides input hysteresis (ΔVT) of 0.6–1.6 V depending on supply voltage, meaning VT+ and VT− differ significantly-for example, 3.15 V and 2.2 V respectively at 4.5 V. This gap prevents multiple toggles when input signals cross the threshold slowly or with superimposed noise. As a result, the SN74HCS72PWR reliably captures clean logic transitions from noisy sources like CAN RX lines or mechanical switches without external filtering-directly addressing the "Enable CAN Controller Power with wake-up pattern" use case cited in its official documentation.

Is the SN74HCS72PWR pin-compatible with the older SN74HC72?

No, the SN74HCS72PWR is not pin-compatible with the SN74HC72. While both are dual D-type flip-flops in 14-pin packages, the SN74HC72 lacks Schmitt-trigger inputs and uses standard CMOS inputs with no hysteresis. Its pin functions differ: SN74HC72 has different input thresholds, no guaranteed noise rejection, and distinct timing behavior. The SN74HCS72PWR's pinout matches only other HCS-family variants (e.g., SN74HCS72DR), not legacy HC-series parts. Substitution requires full schematic and layout review.