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Texas Instruments SN74ALS577ADWR
- Part No.:
- SN74ALS577ADWR
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74ALS577ADWR.pdf
- Description:
- IC FF D-TYPE SNGL 8BIT 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,277
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Product details
Overview
SN74ALS577ADWR from Texas Instruments is an octal D-type edge-triggered flip-flop with 3-state inverting outputs, designed for bus driving in digital systems. It features synchronous clear (CLR), buffered control inputs, and operates at up to 30 MHz clock frequency over 0°C to 70°C. It drives TTL-compatible bus lines directly and retains data during output disable.
For engineers reviewing the SN74ALS577ADWR datasheet, SN74ALS577ADWR pinout, SN74ALS577ADWR application, or SN74ALS577ADWR equivalent, this device is selected for high-speed bidirectional bus interfaces requiring latch-and-drive capability, low propagation delay (≤14 ns), and robust 3-state control in legacy industrial control and data acquisition systems.
Technical Context
This device implements eight independent D-type latches triggered on the low-to-high CLK transition, each with separate 3-state inverting output enabled by OE. The synchronous CLR input resets all Q outputs to logic high simultaneously, independent of clock edge timing.
Its bus-structured pinout (dual-row SOIC-24) separates data inputs (1D–8D), outputs (1Q–8Q), and control signals (CLK, OE, CLR) to minimize crosstalk. Buffered OE and CLR inputs reduce loading on upstream drivers and support clean enable/disable sequencing across multi-device buses.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | Advanced Low-Power Schottky (ALS), TTL-compatible input/output thresholds |
| Max Clock Frequency | 30 MHz - supports 33.3 ns minimum clock period in synchronous bus register applications |
| Propagation Delay (tPLH/tPHL) | 4–14 ns - ensures sub-15 ns timing margin for 25 MHz system clocks with setup/hold compliance |
| Output Drive (IOL/IOH) | 24 mA sink / −2.6 mA source - directly drives 10+ standard TTL loads without external buffers |
| 3-State Enable/Disable Time | tPZH/tPHZ ≤ 4 ns - enables fast bus turnaround in time-multiplexed I/O architectures |
| Supply Voltage Range | 4.5 V to 5.5 V - compatible with regulated +5 V rails and tolerant of ±10% supply variation |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade embedded control and instrumentation environments |
Pinout & Package
SN74ALS577ADWR is housed in a 24-pin plastic small-outline integrated circuit (SOIC-DW) package, 7.5 mm wide, 15.4 mm long, 2.65 mm max height, with 1.27 mm pitch and RoHS-compliant NiPdAu lead finish (Level-1 moisture sensitivity).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OE (Output Enable) | Active-low 3-state control; disables all Q outputs to high-impedance without affecting internal latch state |
| 2–9 | 1D–8D | Data inputs for eight D-type flip-flops; sampled on CLK↑ rising edge |
| 10 | GND | Ground reference for logic and power return path |
| 11–18 | 1Q–8Q | Inverting 3-state outputs; logic high when disabled, inverted D value when enabled |
| 19 | VCC | +5 V supply pin; requires local 0.1 µF ceramic decoupling |
| 20 | CLK | Clock input; edge-triggered on low-to-high transition for synchronous data capture |
| 21 | CLR | Synchronous clear; forces all Q outputs high on next CLK↑ when asserted low |
| 22–24 | NC | No internal connection; must be left unconnected per datasheet |
Key Features
| Feature | Design Value |
|---|---|
| Octal D-type with synchronous clear | Enables atomic reset of all eight registers in one clock cycle-critical for bus arbitration and error recovery |
| Bus-structured pinout | Groups inputs (2–9), outputs (11–18), and controls (1,20,21) to simplify PCB routing and reduce signal skew |
| Buffered OE and CLR inputs | Reduces fan-out burden on upstream logic and prevents false triggering from noise on control lines |
| 3-state inverting outputs | Provides active-low drive polarity matching legacy bus protocols while enabling bidirectional data flow via external direction control |
| TTL-compatible voltage thresholds | VIH = 2.0 V, VIL = 0.8 V - ensures interoperability with standard 74LS/74F logic without level-shifting |
Applications
| Industrial PLC I/O Expansion | Legacy Bus Interface Adapter |
|---|---|
Use Scenario: Adding parallel digital I/O to programmable logic controllers using ISA or STD bus backplanes. IC Role / Device Role / Timing Role: Acts as an octal latch/register with 3-state bus drivers, synchronizing field I/O data to the controller's clock domain and isolating bus segments during configuration. Use Value: Enables direct connection of 8-bit sensor/actuator data without glue logic, leveraging 24 mA drive strength to meet backplane loading requirements. | Use Scenario: Bridging modern microcontrollers to legacy 8-bit parallel peripherals (e.g., printers, modems, EPROM programmers). IC Role / Device Role / Timing Role: Provides edge-triggered data capture and bus-isolated output driving, with synchronous CLR supporting hardware reset coordination across multiple interface chips. Use Value: Eliminates need for discrete buffers and latches; 14 ns max tPLH ensures timing closure at 25 MHz bus rates. |
| Test Equipment Data Capture | Digital Signal Acquisition Module |
Use Scenario: Capturing parallel digital waveforms from DUTs in automated test systems with precise clock alignment. IC Role / Device Role / Timing Role: Functions as a synchronized sampling register, capturing 8-bit status or measurement data on CLK↑ with guaranteed setup/hold margins (tsu = 15 ns, th = 0 ns). Use Value: Synchronous CLR allows deterministic initialization before each test sequence, improving repeatability and reducing software overhead. | Use Scenario: Buffering and latching analog-to-digital converter outputs in multi-channel data loggers. IC Role / Device Role / Timing Role: Holds ADC parallel output data stable during microcontroller read cycles, with OE-controlled 3-state isolation preventing bus contention during conversion. Use Value: 3-state outputs allow shared bus architecture across multiple ADC channels, reducing interconnect count and board area. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal D-type latch with 3-state output applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS576BDWR | Lacks synchronous CLR; uses asynchronous master reset (MR) instead; same pinout except pin 21 is MR, not CLR | Less suitable for systems requiring atomic register reset aligned to clock edge; preferred where asynchronous reset suffices | Select SN74ALS576BDWR only if synchronous timing of reset is unnecessary and MR functionality meets design intent |
| SN74AS576N | Faster (125 MHz max), higher drive (48 mA sink), but wider supply range (4.5–5.5 V) and no synchronous CLR; PDIP-20 package differs from SOIC-24 | Better for high-speed bus buffering but incompatible pinout and thermal profile; requires PCB redesign | Choose SN74AS576N only when speed >30 MHz is mandatory and layout changes are acceptable |
Compared with SN74ALS576BDWR and SN74AS576N, the SN74ALS577ADWR uniquely combines synchronous clear, SOIC-24 bus-optimized pinout, and 30 MHz operation-making it the only drop-in solution for legacy designs requiring clock-aligned reset without layout modification.
Availability
SN74ALS577ADWR is available at Aetrix Electronics and suitable for industrial control, test equipment, and legacy bus interface applications requiring stable component supply and long-term obsolescence management.
Supply support for SN74ALS577ADWR 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 50 years of innovation in industrial and automotive electronics.
The SN74ALS577ADWR belongs to TI's legacy ALS logic family, engineered for reliable, low-power, high-speed digital interfacing in commercial-grade embedded systems and instrumentation.
FAQ
What is the function of pin 21 on the SN74ALS577ADWR?
Pin 21 on the SN74ALS577ADWR is the synchronous clear (CLR) input. When asserted low, it forces all eight Q outputs to logic high on the next rising edge of the CLK signal. Unlike asynchronous reset, CLR operates synchronously with the clock, ensuring deterministic timing behavior critical for bus arbitration and state-machine initialization in the SN74ALS577ADWR.
Does the SN74ALS577ADWR support hot insertion or live bus swapping?
The SN74ALS577ADWR does not include explicit hot-swap protection circuitry. Its absolute maximum rating allows up to 5.5 V on disabled 3-state outputs, but sustained exposure to bus transients during insertion may exceed safe limits. For live bus applications, external series resistors and clamping diodes are recommended. The SN74ALS577ADWR's 3-state outputs isolate the device electrically when OE is high, but full hot-swap compliance requires system-level design beyond the SN74ALS577ADWR's specifications.
What is the minimum pulse width required for the CLK input of the SN74ALS577ADWR?
The SN74ALS577ADWR requires a minimum pulse width of 16.5 ns for both high and low states of the CLK signal, as specified in the recommended operating conditions. This ensures reliable edge detection and internal state capture. Violating this specification risks metastability or missed clock edges. The SN74ALS577ADWR's tw requirement is verified across the full 0°C to 70°C temperature range and 4.5 V to 5.5 V supply range.
Can the SN74ALS577ADWR drive standard TTL loads directly?
Yes, the SN74ALS577ADWR can drive standard TTL loads directly. Its low-level output current (IOL) is rated at 24 mA minimum, sufficient to sink current from up to 10 standard TTL inputs (each requiring ~1.6 mA). Its VOL remains ≤0.4 V under this load, meeting TTL logic-low threshold requirements. This capability eliminates the need for external buffer stages in most legacy TTL bus implementations using the SN74ALS577ADWR.
Is the SN74ALS577ADWR pin-compatible with the SN74ALS576B series?
No, the SN74ALS577ADWR is not pin-compatible with the SN74ALS576B series. While both are octal D-type devices in SOIC packages, the SN74ALS577ADWR uses a 24-pin SOIC-DW package with dedicated CLR (pin 21) and three NC pins (22–24), whereas SN74ALS576BDWR uses a 20-pin SOIC-DW with MR (master reset) on pin 19 and no NC pins. The pin count, assignment, and control signal mapping differ fundamentally between the SN74ALS577ADWR and SN74ALS576B variants.
SN74ALS577ADWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Master Reset
- Type:
- D-Type
- Output Type:
- Tri-State, Inverted
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Clock Frequency:
- 30 MHz
- Max Propagation Delay @ V, Max CL:
- 14ns @ 5V, 50pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 2.6mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Current - Quiescent (Iq):
- 18 mA
- Input Capacitance:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-SOIC
SN74ALS577ADWR FAQ
1.How can I place an order for SN74ALS577ADWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS577ADWR 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 SN74ALS577ADWR reliable?
The price and inventory of SN74ALS577ADWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS577ADWR is usually 5 days.
3.What payment methods are accepted for SN74ALS577ADWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS577ADWR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS577ADWR?
SN74ALS577ADWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS577ADWR 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 SN74ALS577ADWR?
For technical support, including SN74ALS577ADWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS577ADWR requirements.
6.How does Aetrix verify that SN74ALS577ADWR is sourced from the original manufacturer or authorized distributors?
All SN74ALS577ADWR 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 SN74ALS577ADWR meets industry standards.
7.What is the process for return or replacement of SN74ALS577ADWR?
All SN74ALS577ADWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS577ADWR, 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 SN74ALS577ADWR part is unused and in its original packaging.
Return procedure for SN74ALS577ADWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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