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Texas Instruments SN74LS173ANSRG4
- Part No.:
- SN74LS173ANSRG4
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 16-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74LS173ANSRG4.pdf
- Description:
- IC FF D-TYPE SNGL 4BIT 16SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,204
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Product details
Overview
SN74LS173ANSRG4 from Texas Instruments is a 4-bit D-type register with 3-state outputs, designed for bus-oriented TTL systems. It features independent clock and gated data-enable (G1/G2) and output-control (M/N) inputs, 18 ns typical propagation delay, 50 MHz maximum clock frequency, and operates from 0°C to 70°C. It serves as a bus buffer register in legacy industrial control and data acquisition systems.
For engineers reviewing the SN74LS173ANSRG4 datasheet, SN74LS173ANSRG4 pinout, SN74LS173ANSRG4 application, or SN74LS173ANSRG4 equivalent, key selection criteria include its 3-state bus interface capability, parallel-load timing behavior, TTL-compatible input thresholds (VIH = 2 V, VIL = 0.8 V), and PDIP-16 package compatibility with through-hole legacy designs.
Technical Context
This device implements four edge-triggered D-type flip-flops with synchronous parallel load and asynchronous clear. Its dual output-control inputs (M and N) enable/disable all four outputs simultaneously into high-impedance state independently of clock activity, supporting time-multiplexed bus sharing.
The SN74LS173ANSRG4 uses low-power Schottky (LS) TTL logic, delivering 12 mA low-level and –2.6 mA high-level output drive at VCC = 5 V, with guaranteed 25 ns minimum pulse width on CLK and CLR, and 17 ns data setup time relative to clock edge.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | 74LS TTL - ensures compatibility with legacy 5 V TTL systems and predictable noise margins. |
| Max Clock Frequency | 50 MHz - supports high-speed parallel data latching in bus arbitration and control register applications. |
| Propagation Delay | 18 ns typical (tPLH/tPHL) - enables tight timing budgets in synchronous digital subsystems. |
| Output Drive | 12 mA sink / –2.6 mA source - sufficient to drive two standard 74LS loads directly on shared buses. |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade embedded and instrumentation environments. |
| Supply Voltage | 4.75 V to 5.25 V - tight regulation tolerance maintains stable switching thresholds and fanout. |
| Input Thresholds | VIH = 2.0 V, VIL = 0.8 V - matches standard TTL logic levels for seamless integration without level-shifting. |
Pinout & Package
SN74LS173ANSRG4 is supplied in a 16-pin plastic dual in-line package (PDIP-N), with 0.3-inch body width and through-hole mounting. Pin spacing is 0.1 inch, compatible with standard 0.1" pitch PCB footprints and socketing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (M) | Output Control A | Active-low enable for 3-state outputs; high disables all Q outputs regardless of clock or data state. |
| 2 (N) | Output Control B | Second active-low output enable; both M and N must be low for normal Q output operation. |
| 3 (1Q) | Output A | 3-state buffered output of first D-flip-flop; high-impedance when M or N is high. |
| 4 (2Q) | Output B | 3-state buffered output of second D-flip-flop; shares same enable logic as 1Q. |
| 5 (3Q) | Output C | 3-state buffered output of third D-flip-flop; synchronized to common clock and clear. |
| 6 (4Q) | Output D | 3-state buffered output of fourth D-flip-flop; supports full 4-bit parallel bus interface. |
| 7 (CLK) | Clock Input | Positive-edge-triggered clock; initiates parallel load only when G1 and G2 are both low. |
| 8 (GND) | Ground | Reference return path for all logic and output currents; requires low-impedance connection. |
| 9 (VCC) | Power Supply | +5 V supply; decoupling capacitor (0.1 µF) recommended near pin for noise suppression. |
| 10 (CLR) | Asynchronous Clear | Active-high reset; forces all Q outputs low immediately, overriding clock and enable states. |
| 11 (G2) | Data Enable B | Active-low gate for data loading; both G1 and G2 must be low to capture D-inputs on CLK edge. |
| 12 (G1) | Data Enable A | First data gate input; complements G2 to prevent partial or unintended register updates. |
| 13 (4D) | Data Input D | Fourth parallel data input; sampled on rising CLK edge only when G1=G2=low. |
| 14 (3D) | Data Input C | Third parallel data input; synchronous with other D inputs under identical gating conditions. |
| 15 (2D) | Data Input B | Second parallel data input; no internal hold time dependency on adjacent bits. |
| 16 (1D) | Data Input A | First parallel data input; fully independent timing per function table requirements. |
Key Features
| Feature | Design Value |
|---|---|
| Fully independent clock and clear | Enables reliable hold/parallel-load modes without race conditions or metastability in legacy bus systems. |
| Gated 3-state output control (M/N) | Allows deterministic bus release before next device asserts, minimizing bus contention risk in multi-register systems. |
| TTL-compatible input thresholds | VIH = 2.0 V and VIL = 0.8 V ensure interoperability with 74xx, 74LSxx, and 74Sxx families without external biasing. |
| High fanout capability | Up to 49 outputs can drive one additional 74LS load on a shared bus - validated per datasheet bus-loading rules. |
| Asynchronous active-high clear | Provides immediate register reset independent of clock phase, critical for system initialization and fault recovery. |
Applications
| Industrial PLC I/O Expansion | Legacy Test Equipment Data Capture |
|---|---|
|
Use Scenario: Expanding discrete I/O points in programmable logic controllers using shared backplane buses. IC Role / Device Role / Timing Role: Bus-buffered 4-bit latch holding status or command bits between CPU and peripheral modules. Use Value: Enables direct connection to 5 V TTL backplanes without pull-ups or bus transceivers, reducing component count and board space. |
Use Scenario: Capturing parallel sensor or switch data in automated test fixtures with microcontroller-based controllers. IC Role / Device Role / Timing Role: Synchronous sampling register that freezes analog-to-digital converter outputs or switch matrix states. Use Value: Provides precise edge-aligned capture with 17 ns setup time margin, ensuring reliable data acquisition at up to 50 MHz clock rates. |
| Computer System Address Latching | EPROM Programming Interface |
|
Use Scenario: Latching lower address bits during memory access cycles in 8-bit microcomputer systems (e.g., Z80, 8080). IC Role / Device Role / Timing Role: Address register holding A0–A3 while higher bits are multiplexed or generated separately. Use Value: Matches 8080/Z80 bus timing with 25 ns minimum CLK pulse width and 10 ns hold time compliance. |
Use Scenario: Providing controlled 4-bit data staging between programmer controller and EPROM address/data pins. IC Role / Device Role / Timing Role: Isolated data register preventing backdrive during EPROM write/verify cycles. Use Value: 3-state outputs eliminate contention during programming voltage transitions, improving reliability of byte-programming sequences. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 4-bit D-type register with 3-state output applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS174N | 6-bit register with common clock and clear, but no separate output-enable inputs (M/N); outputs always active unless cleared. | Lacks bus isolation capability - unsuitable where multiple devices share a common data bus. | Select SN74LS174N only for non-bus applications requiring extra bit capacity and simpler control. |
| SN74ALS173AN | Advanced LS variant: 12 ns propagation delay, 60 MHz max clock, lower ICC (15 mA), but higher VIH (2.3 V) and tighter VCC tolerance (4.75–5.25 V). | Improved speed and power efficiency, but requires verification of input voltage compatibility with driving logic. | Choose SN74ALS173AN when upgrading legacy systems needing faster timing or reduced power, provided VIH margin is maintained. |
Compared with SN74LS173ANSRG4, SN74LS174N sacrifices bus controllability for higher bit density, while SN74ALS173AN delivers measurable performance gains at the cost of stricter supply and interface constraints - both require layout or logic-level review before substitution.
Availability
SN74LS173ANSRG4 is available at Aetrix Electronics and suitable for industrial control, legacy test equipment, and computer system design requiring stable component supply and long-term obsolescence management.
Supply support for SN74LS173ANSRG4 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 and embedded processing technologies with broad industrial, automotive, and communications product portfolios.
The SN74LS173ANSRG4 belongs to TI's legacy 74LS logic family, engineered specifically for robust, pin-compatible replacement of earlier 74173 registers in bus-oriented TTL systems requiring 3-state drive and deterministic timing.
FAQ
What is the function of the M and N pins on the SN74LS173ANSRG4?
The M and N pins are active-low output control inputs. When both are low, the four Q outputs reflect the registered data values. If either M or N is high, all Q outputs enter high-impedance state - this allows safe bus sharing without requiring external tri-state buffers. The SN74LS173ANSRG4 uses this dual-input scheme to reduce risk of momentary bus contention during enable transitions.
Does the SN74LS173ANSRG4 support asynchronous operation?
Yes - the SN74LS173ANSRG4 features an asynchronous active-high CLR input that forces all Q outputs low immediately, regardless of clock state or enable conditions. This function operates independently of G1, G2, M, or N signals and meets 10 ns minimum inactive-state hold time per datasheet timing requirements.
Can the SN74LS173ANSRG4 drive standard TTL loads directly?
Yes - the SN74LS173ANSRG4 is rated to drive up to two standard 74LS TTL loads per output when enabled, and up to 49 outputs may share a common bus while maintaining valid logic levels. Its 12 mA sink and –2.6 mA source capability meet 74LS fanout specifications without external components.
What is the minimum clock pulse width required for reliable operation of the SN74LS173ANSRG4?
The SN74LS173ANSRG4 requires a minimum CLK high- and low-time of 25 ns each under recommended operating conditions (VCC = 4.75–5.25 V, TA = 0°C to 70°C). This 50 ns minimum period supports up to 20 MHz fundamental clock rate, though the device achieves 50 MHz maximum due to optimized internal timing paths.
Is the SN74LS173ANSRG4 RoHS compliant?
Yes - the SN74LS173ANSRG4 carries NIPDAU (nickel-palladium-gold) lead finish and is RoHS compliant per TI's packaging addendum. It is rated Level-1-260°C-unlimited for moisture sensitivity and intended for standard reflow soldering processes in commercial-grade assembly.
SN74LS173ANSRG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LS
- Package/Case:
- 16-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Master Reset
- Type:
- D-Type
- Output Type:
- Tri-State, Non-Inverted
- Number of Elements:
- 1
- Number of Bits per Element:
- 4
- Clock Frequency:
- 50 MHz
- Max Propagation Delay @ V, Max CL:
- 25ns @ 5V, 45pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 2.6mA, 24mA
- Voltage - Supply:
- 4.75V ~ 5.25V
- Current - Quiescent (Iq):
- 24 mA
- Input Capacitance:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SO
SN74LS173ANSRG4 FAQ
1.How can I place an order for SN74LS173ANSRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LS173ANSRG4 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for SN74LS173ANSRG4 reliable?
The price and inventory of SN74LS173ANSRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS173ANSRG4 is usually 5 days.
3.What payment methods are accepted for SN74LS173ANSRG4?
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4.How is shipping managed for SN74LS173ANSRG4?
SN74LS173ANSRG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LS173ANSRG4 order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for SN74LS173ANSRG4?
For technical support, including SN74LS173ANSRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS173ANSRG4 requirements.
6.How does Aetrix verify that SN74LS173ANSRG4 is sourced from the original manufacturer or authorized distributors?
All SN74LS173ANSRG4 products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SN74LS173ANSRG4 meets industry standards.
7.What is the process for return or replacement of SN74LS173ANSRG4?
All SN74LS173ANSRG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS173ANSRG4, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The SN74LS173ANSRG4 part is unused and in its original packaging.
Return procedure for SN74LS173ANSRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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