Texas Instruments SN74ACT7808-30PAG

Overview

SN74ACT7808-30PAG from Texas Instruments is a 2048-word × 9-bit strobed FIFO memory IC with 30 ns access time, programmable almost-full/almost-empty flags, and 58°C/W thermal impedance in the 64-pin reduced-height quad flat (PAG) package. It supports asynchronous or coincident load/unload clocks and operates from 0°C to 70°C for industrial data buffering applications.

For engineers reviewing the SN74ACT7808-30PAG datasheet, SN74ACT7808-30PAG pinout, SN74ACT7808-30PAG application, or SN74ACT7808-30PAG equivalent, key selection criteria include its 33.3 MHz max clock frequency, 20 ns typical fall-through time, 9-bit parallel I/O, depth/width expansion logic, and status flag behavior under reset and cascading conditions.

Technical Context

The SN74ACT7808-30PAG implements a dual-clock, bit-parallel FIFO using advanced CMOS technology with independent write (LDCK) and read (UNCK) pointers, full/half-full/empty/AF-AE status generation, and on-chip reset logic that initializes FULL and AF/AE high while setting EMPTY and HF low. Its expansion architecture uses XI/XO loopback and CASEN/FL control for depth cascading.

Flag logic is fully synchronous to respective clocks: FULL deasserts only after LDCK rising edge when space exists; EMPTY deasserts only after UNCK rising edge when data is present; HF asserts at ≥1024 words; AF/AE is programmable via D0–D8/DP9 latched on first two LDCK edges with PEN low, supporting offsets X/Y up to 1023.

Key Specifications

Pinout & Package

SN74ACT7808-30PAG uses a 64-pin reduced-height quad flat (PAG) package with 0.5 mm pitch, exposed thermal pad, and lead-free finish. Pin functions are validated per TI SCAS205E datasheet Figure 1 (PAG top view) and Terminal Functions table.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ACT7808-30PAG, SN74ACT7804-30PAG offers identical interface and timing in a smaller buffer, while 7203L15TPG delivers faster access but sacrifices programmability and cascading capability - making SN74ACT7808-30PAG optimal for flexible, scalable buffering where adaptive flow control matters.

Availability

SN74ACT7808-30PAG is available at Aetrix Electronics and suitable for industrial protocol bridges, high-speed data acquisition systems, video line buffering, and automated test equipment requiring stable component supply across extended production lifecycles.

Supply support for SN74ACT7808-30PAG 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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The SN74ACT7808 belongs to TI's advanced CMOS logic FIFO family designed specifically for high-reliability, mixed-clock-domain buffering in real-time data interfaces where deterministic latency and expandable memory depth are critical.

FAQ

What is the maximum clock frequency supported by the SN74ACT7808-30PAG?

The SN74ACT7808-30PAG supports a maximum clock frequency of 33.3 MHz for both LDCK and UNCK inputs, as specified in the timing requirements table for the -30 speed grade. This rating assumes CL = 50 pF and operation within recommended voltage (4.5 V–5.5 V) and temperature (0°C–70°C) ranges. Exceeding this frequency may result in setup/hold violations or invalid flag transitions.

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

After RESET, the SN74ACT7808-30PAG allows programming of almost-empty (X) and almost-full (Y) offsets via D0–D8 and DP9. With PEN low, the first LDCK↑ latches X; a second LDCK↑ (with PEN still low) latches Y. Default values are X = Y = 256 if PEN remains high. The AF/AE flag goes high when word count ≤ X or ≥ (2048 − Y), enabling custom backpressure signaling.

Can multiple SN74ACT7808-30PAG devices be cascaded for greater depth, and what pins are required?

Yes, SN74ACT7808-30PAG supports unlimited depth cascading using XI, XO, CASEN, and FL pins. All devices in the chain require CASEN = low; the first device needs FL = low, others FL = high; XO of each device connects to XI of the next, with the last XO looping to the first XI. Full/Empty status must be externally combined across the chain.

What happens to the Q outputs during RESET on the SN74ACT7808-30PAG?

During RESET, the SN74ACT7808-30PAG resets internal stack pointers and drives FULL and AF/AE high, EMPTY and HF low, but the Q0–Q8 outputs retain their last valid logic states and are not forced to any defined level. Output-enable (OE) remains active, so Q outputs stay driven unless OE is separately asserted low.

Is the SN74ACT7808-30PAG compatible with 3.3 V logic systems?

No, the SN74ACT7808-30PAG is not compatible with 3.3 V logic systems. It requires a 4.5 V to 5.5 V supply (VCC) and specifies VIH = 2 V for control inputs - insufficient for reliable 3.3 V high-level recognition. Using it with 3.3 V signals risks incorrect flag assertion, metastability on clocks, or failure to register data; level-shifting circuitry is mandatory for interfacing with 3.3 V domains.