Texas Instruments SN74HC175NG4

Overview

SN74HC175NG4 from Texas Instruments is a quadruple positive-edge-triggered D-type flip-flop with asynchronous clear (CLR), complementary Q and Q̅ outputs per stage, 2–6 V supply operation, 13 ns typical propagation delay at 6 V, and ±4 mA output drive capability. It serves as a synchronous storage register in digital control logic, data latching, and state-holding circuits within industrial PLC I/O modules.

For engineers reviewing the SN74HC175NG4 datasheet, SN74HC175NG4 pinout, SN74HC175NG4 application, or SN74HC175NG4 equivalent, key selection criteria include its 16-pin PDIP package, direct-clear functionality, dual-rail output architecture, and compatibility with legacy 74HC logic families in board-level redesigns requiring discrete register elements.

Technical Context

This device implements four independent D-type latches synchronized to the rising edge of CLK, each with dedicated CLR input enabling simultaneous reset across all stages. Its CMOS design ensures rail-to-rail output swing, low static current (≤80 μA), and high noise immunity via defined VIH/VIL thresholds across 2–6 V operation.

The SN74HC175NG4 features complementary outputs (Q/Q̅) per flip-flop, eliminating need for external inverters in toggle or differential signaling paths. Timing behavior is characterized by setup time (tsu = 17 ns min at 6 V), hold time (th = 0 ns), and clock pulse width (tw = 14 ns min high/low at 6 V), supporting reliable operation up to 29 MHz maximum clock frequency.

Key Specifications

Pinout & Package

SN74HC175NG4 uses a 16-pin plastic dual in-line package (PDIP-N), 19.31 mm × 6.35 mm body size, through-hole mountable with 2.54 mm pitch. RoHS-compliant lead finish (NIPDAU), no MSL rating required (tube packaging).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC175NG4, SN74HC174N provides two additional flip-flops but removes Q̅ outputs and uses a shared CLR, reducing flexibility in independent-stage reset; CD74HC175E matches function and pinout exactly but is obsolete and lacks current lifecycle support.

Availability

SN74HC175NG4 is available at Aetrix Electronics and suitable for industrial control systems, test instrumentation, and legacy logic upgrades requiring stable component supply, long-term obsolescence management, and full traceability.

Supply support for SN74HC175NG4 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 U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic solutions with broad industrial, automotive, and consumer market reach.

The SN74HC175NG4 belongs to TI's 74HC logic family, designed for low-power, high-noise-immunity digital interfacing and synchronous data storage in cost-sensitive, space-constrained applications.

FAQ

What is the maximum clock frequency supported by SN74HC175NG4?

The SN74HC175NG4 supports a maximum clock frequency of 29 MHz at 6 V supply and 25 °C ambient temperature, as specified in the switching characteristics table. This limit derives from propagation delay (tpd ≤ 32 ns) and setup/hold timing constraints. At lower voltages (e.g., 2 V), fmax drops to 5 MHz due to reduced slew rate and increased internal delays. Designers must verify timing margins under worst-case voltage, temperature, and load conditions.

Does SN74HC175NG4 require external pull-up or pull-down resistors on unused inputs?

Yes - all unused inputs of SN74HC175NG4 must be tied to either VCC or GND to prevent floating nodes, which can cause excessive ICC, erratic output behavior, or ESD susceptibility. TI explicitly recommends this in Section 6.2 of the datasheet. For example, unconnected D inputs should be grounded, and unused CLR should be pulled high via 10 kΩ resistor to ensure normal operation of active-low reset functionality.

Can SN74HC175NG4 operate reliably at 3.3 V supply?

Yes - SN74HC175NG4 is fully specified for 2–6 V operation, including 3.3 V. At 3.3 V, VIH is 2.31 V (70% of VCC), VIL is 0.99 V (30% of VCC), and output drive is ±4 mA typical. Logic thresholds remain compatible with 3.3 V microcontrollers and FPGAs, and propagation delay increases to ~18 ns, supporting >15 MHz clock rates in most 3.3 V systems.

What is the purpose of the complementary Q and Q̅ outputs in SN74HC175NG4?

The complementary outputs (Q and Q̅) in each of the four flip-flops of SN74HC175NG4 eliminate the need for external inverters when both true and inverted signals are required - such as driving differential bus transceivers, implementing XOR-based parity generators, or enabling dual-edge triggered logic. This reduces component count, propagation skew, and board area in applications like memory address latching and bidirectional data control.

Is SN74HC175NG4 pin-compatible with older 74LS175 devices?

No - SN74HC175NG4 is not pin-compatible with 74LS175. While both are 16-pin DIP quad D-type flip-flops with similar pin numbering (e.g., CLK on Pin 3, CLR on Pin 1), LS logic uses different input thresholds, output drive strength, and power supply requirements (LS requires 5 V ±5%, HC supports 2–6 V). Direct substitution may cause timing violations or logic-level incompatibility without level-shifting or redesign.