Texas Instruments SN74LVC573APW

SN74LVC573APW Texas Instruments Product Summary

The SN74LVC573APW from Texas Instruments is an octal transparent D-type latch integrated circuit featuring 3-state outputs and fabricated in a 20-pin TSSOP package. Designed for contemporary digital designs, SN74LVC573APW operates within a wide supply voltage range, making it suitable for buffering and data latching applications in systems requiring robust bus interfacing. With a single channel 8:8 configuration, engineers frequently utilize this device for tasks involving input/output port expansion, bidirectional bus driving, and implementing buffer registers within server, PC, telecommunications, and embedded systems.

Main Attributes of SN74LVC573APW

The SN74LVC573APW boasts several technical features anticipating the needs of modern digital logic design:

Wide supply voltage range: Operates from 1.65 V to 3.6 V, supporting compatibility across 1.8 V, 2.5 V, and 3.3 V logic systems.

5 V tolerant inputs: Ensures the device is adept for mixed-voltage operation, crucial when interfacing legacy TTL or 5 V CMOS signals.

Fast propagation delay: A maximum $t_{pd}$ of 6.9 ns (at 3.3 V), enabling operation in high-speed circuits up to 100 MHz.

Robust output characteristics: Supports drive currents up to 24 mA at 3.3 V, optimizing for highly capacitive or low-impedance loads.

Advanced I/O management: Tri-state outputs facilitate connection to shared system buses; $I_{off}$ circuitry enables live insertion and protection during partial power-down scenarios.

High reliability: ESD protection exceeding JESD 22 standards (2000 V Human-Body Model); latch-up immunity beyond 250 mA per JESD 17.

Flexible package options: Available in catalog, enhanced, automotive, and military qualified versions for diverse use cases.

SN74LVC573APW Electrical Characteristics and Timing Details

A deep understanding of electrical performance is essential for reliable product selection. The SN74LVC573APW delivers consistent performance over the recommended operating conditions:

Absolute maximum supply: Not to exceed published limits; operational supply range is 1.65 V to 3.6 V.

Input characteristics: Inputs can surge up to 5.5 V regardless of VCC, with thresholds that support fast rise/fall times and robust noise margins.

Output characteristics: Internal drivers ensure output ground bounce remains below 0.8 V (at 3.3 V, 25°C), and output undershoot stays above 2 V under equivalent conditions.

Timing requirements: Supports propagation delays as low as 6.9 ns, with tight control over output enable/disable transitions ($t_{dis}$ and $t_{en}$, respectively).

Safe output operation: Maximum output load current of 25 mA per channel (50 mA total device), with explicit instruction to avoid pulling outputs above VCC.

Thermal profile: Multiple package options with competitive thermal impedance specifications, ensuring reliable operation across a wide temperature range.

SN74LVC573APW Functional Overview and Operating Modes

Fundamentally, the SN74LVC573APW is built around octal D-type latches, making it versatile for temporary data storage and bus interfacing. Its operational modes are defined by the state of latch-enable (LE) and output-enable (OE) inputs:

Transparent mode: When LE is high, all Q outputs continuously track the D inputs.

Latch mode: When LE transitions low, outputs retain the D input data present at that moment.

Output management: The OE input, when asserted, switches all outputs to a high-impedance state ideal for bus sharing, without affecting the device’s internal data latches. Crucially, new data can be latched while outputs are tri-stated, permitting flexible bus control and minimizing the need for external interface components.

Use Cases for SN74LVC573APW

Engineers select the SN74LVC573APW for a broad spectrum of use cases:

Bus interface and buffer registers: Its tri-state output and high current drive allow robust connection to microcontroller and microprocessor buses.

Bidirectional drivers: The device’s electrical isolation capabilities are ideal for systems with shared resources.

Server and telecom systems: The fast timing, high reliability, and partial power-down support are advantageous for mission-critical networking and infrastructure hardware.

Consumer and embedded electronics: 5 V tolerant inputs and compact packaging enable seamless integration into mixed-voltage systems.

When designing with the SN74LVC573APW, it is essential to plan for proper input signal levels, prevent bus contention during output transitions, and ensure output and input loading align with device specifications.

SN74LVC573APW PCB Layout and Design Recommendations

For robust performance and manufacturability, adhering to layout recommendations is critical:

Power supply bypassing: Install a high-frequency bypass capacitor (0.1 μF) close to each VCC pin, and consider paralleling with larger capacitors to mitigate noise across frequencies.

Input handling: All unused inputs should be tied to logic high or low (VCC or GND) to prevent floating states, which can cause erratic operation or increased current draw.

Output management: In non-transceiver configurations, outputs may remain unconnected unless system logic dictates otherwise; outputs should never be allowed to exceed VCC.

Board design: Refer to IPC-7351 and IPC-7525 standards for pad layout and recommended stencil aperture design for soldering, ensuring good paste release and optimal soldering yield.

SN74LVC573APW Packaging and Mechanical Details

The SN74LVC573APW is available in the industry-standard 20-pin TSSOP package, featuring a maximum height of 1.2 mm and footprint optimized for high-density assemblies. Mechanical data complies with JEDEC MO-153, and minor dimensional tolerances allow integration into various automated assembly systems. For advanced applications, alternative package types (SOIC, VQFN, PDIP, LCCC, and ceramic options) are available across the full SN74LVC573A family, catering to requirements ranging from military to automotive. Detailed board layout and stencil design guidelines are provided to facilitate high-volume manufacturing and long-term reliability.

SN74LVC573APW Power Requirements and Supply Guidelines

Reliable operation depends on proper power supply design:

Supply voltage: Connect within 1.65 V to 3.6 V as dictated by system requirements.

Decoupling: Use low-ESR ceramic capacitors close to each VCC pin to suppress voltage transients and ensure stable logic operation.

Partial power-down support: The SN74LVC573APW's $I_{off}$ circuitry isolates outputs during power loss, protecting against backdrive currents and enabling hot-swappable deployment in modular systems.

SN74LVC573APW Environmental Ratings and Reliability Information

Texas Instruments specifies SN74LVC573APW for high reliability and long operating life:

ESD protection: 2000 V HBM, 200 V Machine Model, 1000 V Charged Device Model.

Latch-up immunity: Exceeds 250 mA, supporting robust operation in electrically noisy or harsh industrial environments.

RoHS and low-halogen/green compliance: Available in lead-free construction with compliance to EU environmental directives, suitable for global distributed manufacturing.

Product status: Currently recommended for new designs, with extended qualified versions for automotive, military, and enhanced reliability applications.

Alternative and Replacement Options for SN74LVC573APW

Engineers seeking drop-in alternatives or close functional equivalents may consider:

SN74LVC573A (full series): Offers catalog, automotive-qualified (SN74LVC573A-Q1), and enhanced product (SN74LVC573A-EP) versions for different reliability or environmental requirements.

SN54LVC573A: Maintains the same functional core with extended temperature range, suitable for military and defense applications.

Package variants within the SNx4LVC573A family: Available in DB, DGV, DW, FK, J, N, NS, PW, RGY, and W packages to accommodate specific board architectures.

Each alternative is qualified to similar electrical and timing specifications. When substituting, confirm pinout compatibility, voltage tolerance, and packaging dimensions.

Conclusion

The SN74LVC573APW from Texas Instruments stands out as a versatile, high-performance octal transparent latch, meeting the rigorous demands of modern digital system design. Its broad feature set—encompassing flexible voltage operation, robust bus interfacing capabilities, advanced reliability features, and comprehensive packaging options—positions it as a preferred solution for engineers and procurement specialists. With strong application support, well-defined electrical characteristics, and a family of compatible/replacement devices, the SN74LVC573APW enables efficient, reliable, and forward-looking system designs for commercial, industrial, and embedded platforms.