Texas Instruments SN74S175NSR

Overview

SN74S175NSR from Texas Instruments is a quadruple D-type flip-flop with asynchronous clear, implemented in TTL-S (Schottky) logic, operating at 0°C to 70°C, featuring 16-pin SOP (NS) package, 10 ns typical propagation delay (t_PLH/t_PHL), and compatible with standard 5 V TTL logic families. It serves as a synchronous data latch and state register in digital control logic, bus interface timing, and clocked sequential circuits.

For engineers reviewing the SN74S175NSR datasheet, SN74S175NSR pinout, SN74S175NSR application, or SN74S175NSR equivalent, this page delivers verified functional identity, validated pin assignments, confirmed timing parameters, real-world use cases, and technically grounded alternative options for legacy TTL system design and repair.

Technical Context

The SN74S175NSR implements four independent edge-triggered D-type flip-flops sharing a common asynchronous active-low clear (CLR̅) input and a single clock (CLK) input. All flip-flops update on the positive-going edge of CLK, with outputs Q_A–Q_D reflecting corresponding D-input states after propagation delay.

Designed for TTL-S logic families, it features Schottky-clamped transistors enabling higher speed than standard TTL while maintaining compatibility with 74LS and 74F logic levels. Its 16-pin SOP package supports surface-mount assembly in space-constrained industrial control and instrumentation PCBs.

Key Specifications

Pinout & Package

SOP (NS) package: 16-pin small-outline plastic package, 0.300" body width, 1.27 mm lead pitch, gull-wing leads, pin 1 marked by notch or bevel.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LS175NSR and SN74F175N, the SN74S175NSR uniquely balances speed (10 ns), SMT compatibility (SOP-16), and legacy TTL-S interoperability-making it optimal for upgrading aging 74S-series systems without changing PCB layout or compromising timing margins.

Availability

SN74S175NSR is available at Aetrix Electronics and suitable for industrial control sequencing, digital instrumentation latching, and legacy bus interface logic requiring stable component supply across extended production lifecycles.

Supply support for SN74S175NSR 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 founded in 1930, specializing in analog, embedded processing, and logic ICs with broad industrial, automotive, and consumer applications.

The SN74S175NSR belongs to TI's legacy 74S logic family, engineered specifically for high-speed digital systems requiring robust TTL-compatible performance with improved speed-power trade-offs over standard 74-series devices.

FAQ

What is the maximum recommended clock frequency for SN74S175NSR?

The SN74S175NSR has a typical propagation delay of 10 ns, supporting reliable operation up to approximately 35 MHz under nominal conditions (V_CC = 5 V, T_A = 25°C). For robust design, engineers should apply timing margins per the datasheet's setup/hold and minimum pulse width specifications - the absolute maximum clock frequency depends on system-level timing closure, not just propagation delay alone. The SN74S175NSR remains stable within its specified 0°C to +70°C range when operated within these constraints.

Is SN74S175NSR pin-compatible with SN74LS175NSR?

Yes, the SN74S175NSR is pin-compatible with SN74LS175NSR: both use identical 16-pin SOP (NS) packages and share identical pin assignments for CLK, D_A–D_D, Q_A–Q_D, Q̅_A–Q̅_D, CLR̅, V_CC, and GND. This allows direct substitution in existing designs where higher speed (10 ns vs. 25 ns) and increased power consumption are acceptable trade-offs. The SN74S175NSR retains full functional equivalence including asynchronous clear behavior and positive-edge triggering.

Does SN74S175NSR support mixed-voltage interfacing with 3.3 V logic?

No, the SN74S175NSR is a 5 V-only TTL-S device with input thresholds referenced to V_CC = 5 V. Its VIH minimum is 2.0 V and VIL maximum is 0.8 V, making it incompatible with direct connection to 3.3 V CMOS outputs without level-shifting. Driving SN74S175NSR inputs from 3.3 V logic risks marginal or failed recognition of HIGH states. The SN74S175NSR requires a 5 V supply and should interface only with other 5 V TTL, LS, or S-family devices unless external translation circuitry is added.

What is the purpose of the Q̅ outputs on SN74S175NSR?

The Q̅ outputs on the SN74S175NSR provide complementary logic states for each of the four flip-flops, eliminating the need for external inverters in applications requiring both true and inverted signals - such as differential bus drivers, toggle-mode counters, or set/reset control paths. Each Q̅ output tracks its corresponding Q output with matching propagation delay, ensuring precise phase relationship. This dual-output capability is intrinsic to the SN74S175NSR's architecture and is electrically verified across its full operating temperature and voltage range.

Can SN74S175NSR be used in place of SN74S174 in a design?

No, the SN74S175NSR is not functionally interchangeable with SN74S174. While both are 16-pin TTL-S D-type flip-flops, the SN74S174 is a hex (six-stage) device with different pinout, no Q̅ outputs, and distinct internal configuration. The SN74S175NSR provides four D-type flip-flops with true/complement outputs and shared clear, whereas SN74S174 offers six D-type latches without complement outputs and different control signal routing. Substituting SN74S175NSR for SN74S174 would require PCB and logic redesign due to pin and functional mismatch.