Texas Instruments SN74ACT7813-15DLR

Overview

SN74ACT7813-15DLR from Texas Instruments is a 64 × 18-bit clocked FIFO memory IC with independent asynchronous read/write clocks, 12 ns access time (50-pF load), 67 MHz maximum data rate, and programmable almost-full/almost-empty flags. It serves as a high-speed buffering interface between mismatched clock domains in digital communication subsystems.

For engineers reviewing the SN74ACT7813-15DLR datasheet, SN74ACT7813-15DLR pinout, SN74ACT7813-15DLR application, or SN74ACT7813-15DLR equivalent, this page delivers verified timing parameters, flag synchronization behavior, bidirectional configuration capability, and SSOP-56 package–specific layout guidance for reliable datapath isolation and clock domain crossing.

Technical Context

The SN74ACT7813-15DLR implements dual-synchronous FIFO architecture with write clock (WRTCLK) and read clock (RDCLK) operating independently-either asynchronously or coincidently. Its input-ready (IR) flag is edge-synchronized to WRTCLK, while output-ready (OR) is synchronized to RDCLK, ensuring deterministic flag assertion timing across clock boundaries.

It features programmable AF/AE offsets (X/Y up to 31) set via D0–D4 during reset using PEN control, and supports bidirectional 64 × 36-bit expansion using two devices without external logic. The FIFO resets asynchronously but requires four rising edges on both clocks to clear internal synchronizers and initialize flags.

Key Specifications

Pinout & Package

SN74ACT7813-15DLR is packaged in a 56-pin Shrink Small-Outline Package (SSOP-DL), 300-mil body width, 25-mil center-to-center lead pitch, RoHS-compliant NIPDAU finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar FIFO memory applications.

Compared with SN74ACT7803-15DL and SN74ACT7805-15DL, the SN74ACT7813-15DLR uniquely delivers native 18-bit width and 64-word depth in a single device-reducing component count and PCB routing complexity for wide parallel interfaces.

Availability

SN74ACT7813-15DLR is available at Aetrix Electronics and suitable for industrial automation controllers, legacy bus adapters, and DSP interface modules requiring stable component supply and long-term obsolescence management.

Supply support for SN74ACT7813-15DLR 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 high-reliability timing and interface ICs.

The SN74ACT7813-15DLR belongs to TI's Widebus™ family of advanced CMOS FIFOs, designed specifically for robust clock-domain crossing in industrial, communications, and computing infrastructure where deterministic latency and flag synchronization are critical.

FAQ

What is the minimum pulse width requirement for WRTCLK and RDCLK on the SN74ACT7813-15DLR?

The SN74ACT7813-15DLR requires a minimum high/low pulse width of 6 ns for both WRTCLK and RDCLK at the -15 speed grade. This ensures reliable register sampling and avoids setup/hold violations in the internal synchronous logic blocks. Pulse widths below this threshold risk metastability or missed clock edges, especially under worst-case voltage and temperature conditions.

How does the SN74ACT7813-15DLR handle power-on initialization?

The SN74ACT7813-15DLR requires an external asynchronous reset pulse upon power-up. RESET must be asserted low while at least four rising edges occur on both WRTCLK and RDCLK to properly initialize the IR, OR, HF, and AF/AE flags. Without this sequence, flag states remain undefined and the FIFO may not operate predictably.

Can the SN74ACT7813-15DLR be used in a bidirectional data path without additional logic components?

Yes-the SN74ACT7813-15DLR supports true bidirectional configuration when paired with a second identical device. One unit handles write-to-read direction and the other handles read-to-write, sharing clocks and enables. No external gates, multiplexers, or control logic are needed, as confirmed in Figure 8 of the official datasheet.

What is the function of the PEN pin on the SN74ACT7813-15DLR, and when must it be used?

The PEN (Program Enable) pin on the SN74ACT7813-15DLR controls loading of custom AF/AE offset values into internal registers. It must be driven low *once* during the reset window-specifically after IR goes high but before the first write-to latch D0–D4 as the AE offset, and *again* on the next WRTCLK↑ to set the AF offset. If PEN remains high, default X=Y=8 applies.

Does the SN74ACT7813-15DLR support 3.3-V operation?

No-the SN74ACT7813-15DLR is specified only for 4.5 V to 5.5 V supply operation per its recommended operating conditions. Its ACT-series inputs require VIH ≥ 2.0 V and VIL ≤ 0.8 V, and output drive strength is characterized at 5 V. Using 3.3 V violates absolute maximum ratings and risks unreliable flag assertion, increased propagation delay, or functional failure.