Texas Instruments SN74ACT7808-30FN

Overview

SN74ACT7808-30FN from Texas Instruments is a 2048 × 9 strobed FIFO memory IC designed for high-speed data buffering between asynchronous clock domains. It delivers 15 ns access time, 33.3 MHz maximum clock frequency, and programmable almost-full/almost-empty flags - enabling precise flow control in digital communication interfaces and video frame buffers.

For engineers reviewing the SN74ACT7808-30FN datasheet, SN74ACT7808-30FN pinout, SN74ACT7808-30FN application, or SN74ACT7808-30FN equivalent, key selection criteria include its 44-pin LCC (FN) package, 9-bit parallel I/O, depth-cascading capability, and support for independent load/unload clocks with status flag timing behavior per SCAS205E.

Technical Context

The SN74ACT7808-30FN implements a dual-clock, bit-parallel FIFO architecture with separate LDCK and UNCK inputs controlling write and read operations on rising edges. Its internal 2048-word × 9-bit RAM uses advanced CMOS logic to achieve fast fall-through (20 ns typical) and low-power operation (400 µA ICC typical).

Status monitoring relies on dedicated open-drain-compatible flags: FULL (active-low), EMPTY (active-low), HF (half-full), and AF/AE (programmable offset). The AF/AE flag supports configurable thresholds via PEN-controlled latching of D0–D8 and DP9 during reset, enabling adaptive buffer management without external logic.

Key Specifications

Pinout & Package

SN74ACT7808-30FN uses a 44-pin plastic leaded chip carrier (PLCC, FN package) with J-lead configuration and 1.27 mm pitch. The package is surface-mountable, RoHS-compliant, and thermally rated at θ_JA = 46°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ACT7804-30FN and 7203L15PFI, the SN74ACT7808-30FN uniquely combines full-depth buffering, on-chip programmable flow control, and plug-and-play depth expansion - reducing system-level timing validation effort and eliminating external status decoding.

Availability

SN74ACT7808-30FN is available at Aetrix Electronics and suitable for video frame buffering, protocol bridging, industrial communication gateways, and test equipment data capture requiring stable component supply and long-term obsolescence management.

Supply support for SN74ACT7808-30FN 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 timing and interface ICs.

The SN74ACT7808-30FN belongs to TI's advanced CMOS FIFO memory product line, engineered specifically for robust asynchronous data transfer in commercial-grade instrumentation, industrial automation, and digital video systems.

FAQ

What is the maximum operating frequency of the SN74ACT7808-30FN?

The SN74ACT7808-30FN supports a maximum clock frequency of 33.3 MHz for both LDCK and UNCK inputs under recommended operating conditions (VCC = 4.5 V to 5.5 V, TA = 0°C to 70°C). This rating is specified in the SCAS205E datasheet timing table for the -30 speed grade and assumes CL = 50 pF load. Exceeding this frequency risks setup/hold violations and metastability in flag outputs.

How does the AF/AE flag programming work on the SN74ACT7808-30FN?

The AF/AE flag on the SN74ACT7808-30FN is programmed after RESET and before the first write cycle by asserting PEN low and applying binary values to D0–D8 and DP9. A single LDCK↑ latches the almost-empty offset (X); a second LDCK↑ (with PEN still low) latches the almost-full offset (Y). Default values are X = Y = 256 if PEN remains high. Programming is confirmed by AF/AE going high post-reset.

Can multiple SN74ACT7808-30FN devices be cascaded for greater depth?

Yes - the SN74ACT7808-30FN includes dedicated depth-cascading logic: CASEN must be tied low on all devices in the chain, FL must be low only on the first device, and XO of each device connects to XI of the next. The last XO loops back to the first XI. Status flags require external OR/NAND logic to generate composite FULL/EMPTY signals across the cascade.

What happens to the Q outputs during SN74ACT7808-30FN reset?

During RESET assertion (low), the SN74ACT7808-30FN resets internal stack pointers and sets FULL high, AF/AE high, HF low, and EMPTY low - but the Q outputs retain their last valid logic states and are not forced to any defined level. Output drivers remain active unless OE is separately asserted low; thus, Q0–Q8 may float or hold previous data depending on bus loading.

Is the SN74ACT7808-30FN pin-compatible with other speed grades in the same family?

Yes - the SN74ACT7808-30FN shares identical 44-pin FN package pinout and logic functionality with SN74ACT7808-20FN, -25FN, and -40FN variants. Only timing parameters differ: access time (15 ns), fall-through time (20 ns), and max clock frequency (33.3 MHz) are specific to the -30 speed grade. No PCB redesign is needed when upgrading or downgrading within the SN74ACT7808 FN-series family.