Texas Instruments SN74LS175NSR

Overview

SN74LS175NSR from Texas Instruments is a quadruple D-type flip-flop with asynchronous clear, implemented in low-power Schottky TTL logic. It features 4 independent edge-triggered storage elements, 16-pin SOP package, guaranteed operation from 0°C to 70°C, and typical propagation delay of 15 ns at V_CC = 5 V. It is used in synchronous data latching, register file construction, and clock-domain synchronization in legacy industrial control systems.

For engineers reviewing the SN74LS175NSR datasheet, SN74LS175NSR pinout, SN74LS175NSR application, or SN74LS175NSR equivalent, this page delivers verified functional identity, confirmed SOP-16 pin mapping, real-world timing parameters, and validated drop-in alternatives for legacy TTL system maintenance and redesign.

Technical Context

The SN74LS175NSR implements four identical D-type flip-flops sharing a common clock (CLK) and master clear (CLR̅) input. Each stage samples the D input on the rising edge of CLK and updates Q output synchronously, while CLR̅ forces all Q outputs low asynchronously when asserted low.

It operates strictly within the LS-TTL electrical family: V_CC = 5 V ±5%, I_OH = –0.4 mA (max), I_OL = 8 mA (min), and compatible with standard TTL and LS-TTL input thresholds. No internal pull-ups, no Schmitt-trigger inputs, and no power-down mode are supported.

Key Specifications

Pinout & Package

SOP-16 (NS) package: 16-lead small-outline package with gull-wing leads, 1.27 mm pitch, 10.2 mm × 5.3 mm body, RoHS-compliant NiPdAu lead finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LS175N, SN74LS175NSR enables automated SMT assembly and saves board space; compared with SN74LS174NSR, it delivers exact 4-bit functionality with preserved pinout for drop-in replacement in existing SOP-16 layouts.

Availability

SN74LS175NSR is available at Aetrix Electronics and suitable for industrial control registers, legacy bus interface latching, and digital test equipment pattern storage requiring stable component supply across long-lifecycle programs.

Supply support for SN74LS175NSR 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 ICs with broad industrial, automotive, and consumer reach.

The SN74LS175NSR belongs to TI's legacy 74LS logic product line, designed specifically for backward-compatible replacement and maintenance of TTL-based digital systems deployed from the 1970s through early 2000s.

FAQ

What is the maximum clock frequency supported by the SN74LS175NSR?

The SN74LS175NSR does not specify a maximum clock frequency in its datasheet. Its usable clock rate is determined by propagation delay (15 ns max) and setup/hold time requirements (20 ns setup, 5 ns hold). For reliable operation, designers typically limit clock periods to ≥40 ns (25 MHz), though actual system margins depend on trace routing, loading, and supply stability. The SN74LS175NSR is intended for use in systems operating well below 10 MHz.

Does the SN74LS175NSR support hot insertion or live insertion into a powered circuit?

No, the SN74LS175NSR does not support hot insertion. Its inputs lack power-up protection circuitry, and applying signals before V_CC is stable may cause latch-up or excessive current draw. Power sequencing must ensure V_CC is applied and stabilized before any input signals - including CLK and CLR̅ - are asserted. This requirement applies to all variants of the SN74LS175NSR.

Can the SN74LS175NSR be used as a 4-bit shift register?

No, the SN74LS175NSR cannot function as a shift register. It contains four independent D flip-flops with no internal serial interconnection between Q and D inputs. To implement shifting, external wiring is required - for example, connecting Q1 to D2, Q2 to D3, and Q3 to D4 - but this consumes additional board space and introduces timing skew. Dedicated shift register ICs like SN74LS164 are better suited for that function.

Is the SN74LS175NSR pin-compatible with CMOS equivalents such as CD4013 or 74HC175?

No, the SN74LS175NSR is not pin-compatible with CD4013 or 74HC175. While all three provide dual or quad D flip-flop functionality, they differ in pin assignment: CD4013 is dual (14-pin), 74HC175 is quad but uses different pin numbering (e.g., CLK on pin 3, CLR̅ on pin 4), and SN74LS175NSR places CLK on pin 12 and CLR̅ on pin 1. Direct substitution requires PCB redesign.

What is the purpose of the complementary outputs (Q̅) on the SN74LS175NSR?

The complementary outputs (Q1̅, Q2̅, Q3̅, Q4̅) on the SN74LS175NSR provide logically inverted versions of each stored bit without requiring external inverters. This enables direct implementation of active-low control signals, differential bus driving, or NAND/NOR-based combinational logic - reducing component count and propagation delay in circuits that require both true and complemented data paths.