Texas Instruments CD74HC173NSRG4

Overview

CD74HC173NSRG4 from Texas Instruments is a high-speed CMOS quad D-type flip-flop with three-state outputs, shared clock (CP), master reset (MR), and dual data enable (E1/E2) and output enable (OE1/OE2) controls. It operates from 2 V to 6 V, delivers 15 LSTTL load drive capability, and supports –55°C to 125°C industrial/military temperature range. It is used in bus-oriented digital systems for synchronous data latching and controlled bus interfacing.

For engineers reviewing the CD74HC173NSRG4 datasheet, CD74HC173NSRG4 pinout, CD74HC173NSRG4 application, or CD74HC173NSRG4 equivalent, key selection criteria include its three-state bus-driving capability, wide supply voltage range, guaranteed propagation delay (≤50 ns at 4.5 V), and compatibility with both CMOS and TTL logic families via input thresholds.

Technical Context

The CD74HC173NSRG4 implements four independent edge-triggered D-type flip-flops sharing CP, MR, E1, E2, OE1, and OE2 control lines. Its synchronous operation on the rising edge of CP enables deterministic state capture across all four bits. The dual output enable architecture allows independent high-impedance control per pair of outputs (Q0–Q1 and Q2–Q3).

Input enable logic feeds Q outputs back to D inputs when E1 or E2 is high, preserving state without clock interruption. Reset is asynchronous and active-high on MR. Output three-state behavior is activated when either OE1 or OE2 is high - sequential operation remains unaffected during output disable.

Key Specifications

Pinout & Package

TSSOP-16 package (5.00 mm × 4.40 mm body size, 1.2 mm max height), lead finish NIPDAU/SN, moisture sensitivity level Level-1-260C-UNLIM, RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD74HC173NSRG4, SN74HC173PWR offers identical functionality with improved manufacturability, while CD74HCT173PWR trades supply flexibility for guaranteed TTL interface compatibility - making the HC variant optimal for scalable, low-power, wide-voltage designs.

Availability

CD74HC173NSRG4 is available at Aetrix Electronics and suitable for industrial bus interface, aerospace data acquisition, digital test equipment, and legacy system emulation requiring stable component supply across extended temperature ranges.

Supply support for CD74HC173NSRG4 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 for industrial, automotive, and aerospace markets.

The CD74HC173NSRG4 belongs to TI's legacy high-speed CMOS logic family, designed specifically for robust, low-power, wide-temperature-range digital interfacing and data latching in mission-critical systems.

FAQ

What is the maximum clock frequency supported by CD74HC173NSRG4?

The CD74HC173NSRG4 supports a maximum clock frequency of 60 MHz at VCC = 5 V and CL = 15 pF. At VCC = 4.5 V and CL = 50 pF, the practical limit is 24 MHz across –40°C to 85°C, and 20 MHz over the full –55°C to 125°C range. These values are measured under specified switching conditions and assume proper layout and decoupling.

Does CD74HC173NSRG4 support true three-state outputs, and how are they controlled?

Yes, CD74HC173NSRG4 provides true three-state outputs via two independent enables: OE1 controls Q0 and Q1, and OE2 controls Q2 and Q3. Either OE pin driven high places its associated outputs in high-impedance state, regardless of clock or data activity. This allows partial bus isolation without affecting internal flip-flop operation.

Can CD74HC173NSRG4 operate at 3.3 V supply voltage?

Yes, CD74HC173NSRG4 is fully specified for operation from 2 V to 6 V, including 3.3 V. At 3.3 V, it maintains guaranteed VIH ≥ 2.31 V and VIL ≤ 1.1 V (30% noise margin), propagation delay ≤65 ns, and output drive sufficient for 10–12 LSTTL loads - making it suitable for mixed-voltage 3.3 V/5 V system interfaces.

How does the dual data enable (E1/E2) feature function in CD74HC173NSRG4?

In CD74HC173NSRG4, asserting E1 high feeds Q0 and Q1 back to D0 and D1, holding their states regardless of CP transitions. Similarly, E2 high holds Q2 and Q3. This enables selective "freeze" of flip-flop pairs without disabling the clock or resetting - useful for pipeline stall or debug state preservation.

Is CD74HC173NSRG4 pin-compatible with older 74LS173 devices?

No, CD74HC173NSRG4 is not pin-compatible with 74LS173. While both are quad D-type flip-flops with three-state outputs, the LS173 uses different pin assignments for enables and outputs. However, CD74HCT173PWR - the TTL-compatible variant - is functionally and pin-compatible with 74LS173 and may serve as a drop-in replacement in 5 V systems.