Texas Instruments SN74ACT7814-20DL

Overview

SN74ACT7814-20DL from Texas Instruments is a 64 × 18-bit strobed FIFO memory IC with 15 ns access time, 50 MHz maximum clock frequency, and programmable almost-full/almost-empty flags. It features full/empty/half-full status outputs, 3-state outputs, and asynchronous or coincident load/unload clocks-used in high-speed data buffering between mismatched bus domains in telecom line cards and industrial controller backplanes.

For engineers reviewing the SN74ACT7814-20DL datasheet, SN74ACT7814-20DL pinout, SN74ACT7814-20DL application, or SN74ACT7814-20DL equivalent, key selection criteria include its 56-pin SSOP (DL) package, 18-bit parallel I/O width, 64-word depth, TTL-compatible input thresholds, and support for word-width expansion to 36 bits via cascading.

Technical Context

The SN74ACT7814-20DL implements a dual-clock, bit-parallel FIFO using advanced CMOS SRAM core with independent load clock (LDCK) and unload clock (UNCK) inputs. Its internal stack pointers track write/read positions, enabling true first-in-first-out operation without address management overhead.

Status logic generates FULL, EMPTY, HF, and programmable AF/AE flags based on real-time word count; AF/AE offset values X and Y are latched from D0–D4 during reset-initiated programming cycles. All outputs-including 18 Q lines and 4 flags-are 3-state controlled by OE, with propagation delays under 20 ns at 50-pF load.

Key Specifications

Pinout & Package

Packaged in a 56-pin Shrink Small-Outline Package (SSOP-DL), 300-mil body width, 25-mil center-to-center lead pitch, JEDEC MO-153 compliant, moisture sensitivity level 1 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ACT7804-20DL and SN74ACT7806-20DL, the SN74ACT7814-20DL uniquely delivers 18-bit parallel throughput at 64-word depth-making it optimal for applications requiring both wide data paths and deterministic low-latency buffering without width reduction or depth compromise.

Availability

SN74ACT7814-20DL is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLC backplanes, video processing subsystems, and network packet buffering requiring stable component supply across extended production lifecycles.

Supply support for SN74ACT7814-20DL 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 decades of experience in high-reliability industrial and communications ICs.

The SN74ACT7814-20DL belongs to TI's Widebus™ family of high-speed interface logic, designed specifically for low-latency, high-fidelity data buffering in synchronous digital systems requiring precise timing control and status feedback.

FAQ

What is the maximum clock frequency supported by the SN74ACT7814-20DL?

The SN74ACT7814-20DL supports a maximum clock frequency of 50 MHz for both LDCK and UNCK inputs, as specified in the timing requirements table for the -20 speed grade. This rating assumes VCC = 4.5 V to 5.5 V and operation within 0°C to 70°C ambient temperature. The device achieves this performance with guaranteed 15 ns access time and propagation delays under 20 ns at 50-pF load.

How is the AF/AE flag programmed on the SN74ACT7814-20DL?

The AF/AE flag on the SN74ACT7814-20DL is programmed after RESET assertion and before the first write cycle: with PEN held low, the binary value on D0–D4 is latched on the first LDCK rising edge as the almost-empty offset (X), and optionally reprogrammed on a second LDCK edge as the almost-full offset (Y). Default values are X = Y = 8 if PEN remains high. Programming disables writes until complete.

Does the SN74ACT7814-20DL support word-width expansion?

Yes, the SN74ACT7814-20DL supports word-width expansion to 36 bits using two devices in cascade configuration, as documented in Figure 6 of the datasheet. This is achieved by connecting LDCK/UNCK/FULL/EMPTY signals in parallel and routing D0–D17 and Q0–Q17 across both units with appropriate enable sequencing-enabling higher bandwidth without switching to custom ASIC solutions.

What is the function of the HF (half-full) output on the SN74ACT7814-20DL?

The HF output on the SN74ACT7814-20DL is a status flag that goes high when the FIFO contains 32 or more words and low when it contains 31 or fewer. It provides mid-depth occupancy feedback useful for dynamic flow control algorithms, such as initiating prefetch or throttling upstream sources before reaching full capacity-reducing risk of overflow in real-time streaming applications.

Is the SN74ACT7814-20DL pin-compatible with other members of the 'ACT78xx family?

Yes, the SN74ACT7814-20DL is pin-to-pin compatible with SN74ACT7804-20DL and SN74ACT7806-20DL per the datasheet, sharing identical 56-pin SSOP (DL) package, power/ground pin locations, clock/control signal assignments, and flag output placements-allowing drop-in replacement where depth or width requirements align, though functional equivalence requires verification of data width and memory size constraints.