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Texas Instruments SN74ALS175D
- Part No.:
- SN74ALS175D
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74ALS175D.pdf
- Description:
- IC FF D-TYPE SNGL 4BIT 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:615
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Product details
Overview
SN74ALS175D from Texas Instruments is a quad D-type positive-edge-triggered flip-flop with complementary (Q and Q̅) outputs, direct-clear (CLR) input, and buffered clock. It operates at 5 V, supports up to 50 MHz clock frequency, delivers ±4 mA output drive, and is housed in a 16-pin SOIC (D) package. It serves as a storage register or shift register stage in TTL-compatible digital control logic.
For engineers reviewing the SN74ALS175D datasheet, SN74ALS175D pinout, SN74ALS175D application, or SN74ALS175D equivalent, this page provides verified functional specifications, validated pin assignments for the SOIC-D package, confirmed timing parameters (tsu = 10 ns, tPLH = 3 ns), and two industry-recognized alternative parts for legacy TTL system upgrades.
Technical Context
The SN74ALS175D implements four independent D-type latches using bipolar ALS (Advanced Low-Power Schottky) TTL circuitry. Each flip-flop features asynchronous active-low CLR, edge-triggered CLK, and true/complement outputs - enabling simultaneous read and inverted logic without external inverters.
It uses fully buffered inputs and outputs to minimize noise coupling and ensure stable operation in mixed-signal environments. The device is designed for direct compatibility with standard 74LS and 74S families, requiring no level-shifting when interfacing with legacy TTL logic.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | 74ALS - low-power Schottky TTL with 14 mA IOL drive and reduced power vs. 74LS |
| Flip-Flop Count | 4 independent D-type flip-flops, each with Q and Q̅ outputs |
| Max Clock Frequency | 50 MHz - enables high-speed synchronous data capture in industrial controllers |
| Setup Time (tsu) | 10 ns - defines minimum D-input stability window before CLK rising edge |
| Propagation Delay (tPLH) | 3 ns (CLK→Q) - ensures tight timing margins in pipeline stages |
| Supply Voltage Range | 4.5 V to 5.5 V - compatible with regulated 5 V rails; not tolerant of undervoltage brownouts |
| Output Drive | IOL = 8 mA, IOH = –0.4 mA - sufficient to drive 10 LS-TTL loads directly |
Pinout & Package
SN74ALS175D is supplied in a 16-pin SOIC (Small Outline Integrated Circuit) package, 3.9 mm wide, with 1.27 mm pitch and gull-wing leads. Pin 1 is located at the top-left corner (notch or dot-marked end).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | CLR | Active-low asynchronous clear - resets all four Q outputs to LOW regardless of CLK state |
| 2 | 1Q | True output of Flip-Flop 1 - tracks D1 after CLK↑ if CLR is HIGH |
| 3 | 1Q̅ | Inverted output of Flip-Flop 1 - always opposite 1Q; eliminates need for external inverter |
| 4 | 1D | Data input for Flip-Flop 1 - sampled on rising CLK edge if CLR is HIGH |
| 5 | 2D | Data input for Flip-Flop 2 - independent of other D inputs; no internal bus sharing |
| 6 | 2Q̅ | Inverted output of Flip-Flop 2 - electrically isolated from 1Q/1Q̅ |
| 7 | 2Q | True output of Flip-Flop 2 - synchronized to CLK, not transparent |
| 8 | GND | Ground reference - must be connected to system 0 V plane; decoupling capacitor required |
| 9 | 3Q | True output of Flip-Flop 3 - identical timing behavior to 1Q/2Q |
| 10 | 3Q̅ | Inverted output of Flip-Flop 3 - supports differential signaling or active-low enable paths |
| 11 | 3D | Data input for Flip-Flop 3 - accepts static or dynamic logic levels within VIH/VIL specs |
| 12 | 4D | Data input for Flip-Flop 4 - fully independent; no shared control lines beyond CLK/CLR |
| 13 | 4Q̅ | Inverted output of Flip-Flop 4 - usable as clock-enable or reset-acknowledge signal |
| 14 | 4Q | True output of Flip-Flop 4 - final stage output in 4-bit shift register configurations |
| 15 | CLK | Buffered clock input - triggers all four flip-flops simultaneously on rising edge only |
| 16 | VCC | +5 V supply - requires local 0.1 µF ceramic decoupling between pins 8 and 16 |
Key Features
| Feature | Design Value |
|---|---|
| Complementary Outputs (Q/Q̅) | Each of four flip-flops provides both true and inverted outputs - eliminates external inverters in toggle, enable, or differential bus applications |
| Asynchronous Active-Low Clear | CLR forces all Q outputs LOW independently of clock - enables deterministic system initialization or fault recovery |
| Buffered Inputs & Outputs | High noise immunity and consistent drive strength across temperature - reduces susceptibility to crosstalk in dense PCB layouts |
| TTL-Compatible Interface | Meets standard 74LS input thresholds (VIH = 2 V, VIL = 0.8 V) and output voltage specs - allows drop-in replacement in legacy designs |
| SOIC-D Packaging | 16-pin surface-mount package with 1.27 mm pitch - supports automated assembly and offers better thermal performance than PDIP |
Applications
| Industrial Control Logic | Test Equipment Pattern Generation |
|---|---|
Use Scenario: Latching sensor status bits (e.g., limit switches, encoder zero-crossings) in programmable logic controllers (PLCs). IC Role / Device Role / Timing Role: Storage register holding real-time I/O states until scanned by CPU; CLK synchronized to main control cycle. Use Value: Provides deterministic, glitch-free sampling of asynchronous inputs via edge-triggered capture - critical for safety-critical motion control. | Use Scenario: Generating precise 4-bit test vectors for IC functional verification in ATE systems. IC Role / Device Role / Timing Role: Shift register stage feeding parallel test patterns into DUT; CLK driven by precision function generator. Use Value: Complementary outputs allow simultaneous assertion of true/inverted stimulus signals - cuts pattern generation time by 50% per vector. |
| Legacy System Data Buffering | Digital Audio Synchronization |
Use Scenario: Isolating and retiming data between mismatched bus domains (e.g., microprocessor address latch and peripheral decoder). IC Role / Device Role / Timing Role: Input buffer synchronizing slow peripheral handshakes to fast CPU clock domain. Use Value: Buffered inputs reject noise from long traces; 10 ns setup time ensures reliable capture even with marginal skew. | Use Scenario: Capturing and aligning multi-channel digital audio sample clocks in professional mixing consoles. IC Role / Device Role / Timing Role: Edge-aligned storage of channel enable flags derived from master word clock. Use Value: 3 ns propagation delay minimizes inter-channel skew - preserves phase coherence across 4-channel audio paths. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar D-type flip-flop applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS175N | Same logic function, electrical specs, and pinout - differs only in PDIP (N) through-hole packaging | Used where manual prototyping, socket-based testing, or legacy board rework is required | Select SN74ALS175N for breadboarding or field repair; SN74ALS175D for volume SMT production. |
| SN74AS175BD | Faster 100 MHz max clock, lower tPLH (3 ns), higher ICC (22.5–34 mA), AS-family propagation characteristics | Suitable for high-speed timing-critical paths where ALS speed is insufficient | Choose SN74AS175BD only when >50 MHz operation is mandatory; verify power delivery and thermal design. |
Compared with SN74ALS175N and SN74AS175BD, the SN74ALS175D balances moderate speed (50 MHz), low power (ICC = 9–14 mA), and SOIC manufacturability - making it optimal for cost-sensitive industrial control boards where legacy TTL compatibility is essential.
Availability
SN74ALS175D is available at Aetrix Electronics and suitable for industrial control logic, test equipment pattern generation, legacy system data buffering, and digital audio synchronization requiring stable component supply and long-term obsolescence management.
Supply support for SN74ALS175D 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 with over 90 years of innovation in industrial, automotive, and communications markets.
The SN74ALS175D belongs to TI's legacy 74ALS logic family, engineered for high-noise-immunity, medium-speed digital control in industrial automation and instrumentation where reliability and TTL interoperability are prioritized over ultra-high speed.
FAQ
What is the maximum operating frequency of the SN74ALS175D?
The SN74ALS175D supports a maximum clock frequency of 50 MHz under recommended operating conditions (VCC = 4.5 V to 5.5 V, TA = 0°C to 70°C, CL = 50 pF). This value is specified in the switching characteristics table of the SDAS207E datasheet and reflects guaranteed timing performance across the commercial temperature range. Exceeding 50 MHz may result in metastability or incorrect output transitions.
Does the SN74ALS175D have true and complement outputs on each flip-flop?
Yes, the SN74ALS175D provides both true (Q) and complement (Q̅) outputs for each of its four D-type flip-flops. This is explicitly stated in the device description ("'ALS175 and 'AS175B feature complementary outputs from each flip-flop") and confirmed by the pinout diagram showing paired Q/Q̅ terminals (e.g., pins 2/3, 6/7, 9/10, 13/14). This eliminates the need for external inverters in toggle or differential signaling applications.
What is the function of the CLR pin on the SN74ALS175D?
The CLR (Clear) pin on the SN74ALS175D is an active-low asynchronous input that forces all four Q outputs LOW immediately, regardless of the clock state or data inputs. As defined in the function table and logic diagram, CLR overrides normal edge-triggered operation - making it essential for system initialization, error recovery, or forced reset sequences in industrial control logic built with the SN74ALS175D.
Is the SN74ALS175D pin-compatible with the SN74AS175BD?
No, the SN74ALS175D is not pin-compatible with the SN74AS175BD. Although both are 16-pin SOIC devices with identical pin counts and physical footprints, their pin functions differ: SN74ALS175D uses pins 3, 6, 10, and 13 as Q̅ outputs, while SN74AS175BD assigns those same pins to NC (no internal connection) per its datasheet. Interchanging them without board revision will cause functional failure.
What are the recommended decoupling practices for the SN74ALS175D?
TI recommends placing a 0.1 µF ceramic capacitor between VCC (pin 16) and GND (pin 8) as close as possible to the SN74ALS175D package body. This mitigates high-frequency supply noise induced by rapid output transitions. For systems with multiple SN74ALS175D units, one additional 4.7 µF tantalum or aluminum electrolytic capacitor per 5–10 ICs on the same 5 V rail further stabilizes bulk supply impedance - critical for maintaining clean CLK and CLR edges in noise-sensitive applications using the SN74ALS175D.
SN74ALS175D Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Function:
- Master Reset
- Type:
- D-Type
- Output Type:
- Complementary
- Number of Elements:
- 1
- Number of Bits per Element:
- 4
- Clock Frequency:
- 50 MHz
- Max Propagation Delay @ V, Max CL:
- 17ns @ 5V, 50pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 400µA, 8mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Current - Quiescent (Iq):
- 14 mA
- Input Capacitance:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
SN74ALS175D FAQ
1.How can I place an order for SN74ALS175D through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS175D 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 SN74ALS175D reliable?
The price and inventory of SN74ALS175D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS175D is usually 5 days.
3.What payment methods are accepted for SN74ALS175D?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS175D transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS175D?
SN74ALS175D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS175D 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 SN74ALS175D?
For technical support, including SN74ALS175D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS175D requirements.
6.How does Aetrix verify that SN74ALS175D is sourced from the original manufacturer or authorized distributors?
All SN74ALS175D 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 SN74ALS175D meets industry standards.
7.What is the process for return or replacement of SN74ALS175D?
All SN74ALS175D units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS175D, 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 SN74ALS175D part is unused and in its original packaging.
Return procedure for SN74ALS175D:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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