Texas Instruments SN74ALVC7806-40DL

Overview

SN74ALVC7806-40DL from Texas Instruments is a 256 × 18-bit low-power asynchronous FIFO memory IC operating from 3.0 V to 3.6 V, delivering 40 MHz data rates and 18 ns access time with 50-pF load. It features programmable almost-full/almost-empty flags, full/empty/half-full status outputs, and 3-state parallel I/O for high-speed buffering in clock-domain crossing applications.

For engineers reviewing the SN74ALVC7806-40DL datasheet, SN74ALVC7806-40DL pinout, SN74ALVC7806-40DL application, or SN74ALVC7806-40DL equivalent, key selection criteria include its 56-pin SSOP (DL) package, dual asynchronous clocks (LDCK/UNCK), 18-bit parallel data width, flag programmability via PEN/D0–D7, and compatibility with 3.3-V logic systems requiring deterministic latency and depth-controlled flow control.

Technical Context

The SN74ALVC7806-40DL implements a 256-word × 18-bit static RAM core with independent write and read pointer logic, enabling true first-in-first-out operation across asynchronous clock domains. Its status flag generation is fully combinational and synchronized to respective clocks, with HF asserted at ≥128 words and FULL/EMPTY driven by pointer comparison logic.

Flag behavior is configurable: AF/AE offset values X (almost-empty) and Y (almost-full) are latched on the first one or two LDCK rising edges after RESET when PEN is low, allowing user-defined thresholds between 0 and 127 words. The FIFO resets all internal pointers and asserts FULL high, EMPTY low, HF low, and AF/AE high upon active-low RESET assertion.

Key Specifications

Pinout & Package

SN74ALVC7806-40DL is housed in a 56-pin Shrink Small-Outline Package (SSOP-DL), 300-mil body width, 25-mil center-to-center lead pitch, RoHS-compliant with NIPDAU finish and MSL Level-1 rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ALVC7806-25DL and SN74ACT7806DW, the SN74ALVC7806-40DL uniquely delivers 40-MHz operation at 3.3 V with programmable AF/AE thresholds-making it optimal for modern low-voltage, high-bandwidth bridging where timing precision and power efficiency are jointly critical.

Availability

SN74ALVC7806-40DL is available at Aetrix Electronics and suitable for industrial PLC data buffering, video frame synchronization, network packet assembly, audio sample rate conversion, and high-speed serial-to-parallel interface bridging requiring stable component supply and long-term lifecycle support.

Supply support for SN74ALVC7806-40DL 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 expertise in high-reliability timing and interface ICs.

The SN74ALVC7806-40DL belongs to TI's Widebus™ family of advanced CMOS FIFO memories, engineered specifically for low-voltage, high-speed inter-domain data buffering in industrial, communications, and multimedia systems.

FAQ

What is the maximum data rate supported by the SN74ALVC7806-40DL?

The SN74ALVC7806-40DL supports a maximum clock frequency of 40 MHz on both LDCK and UNCK inputs, enabling sustained bidirectional data throughput of 720 Mbps (18 bits × 40 MHz). This rating is guaranteed under recommended operating conditions: VCC = 3.0 V to 3.6 V, TA = 0°C to +70°C, and CL = 50 pF. The -40 suffix explicitly denotes this speed grade.

How is the AF/AE flag programmed on the SN74ALVC7806-40DL?

The AF/AE flag on the SN74ALVC7806-40DL is programmed by asserting PEN low after RESET and applying desired offset values to D0–D7 before the first or second LDCK rising edge. The first LDCK↑ latches X (almost-empty), and a second LDCK↑ (with PEN still low) latches Y (almost-full). Default values X=Y=32 apply if PEN remains high. Programming occurs only once per power cycle and disables writes until complete.

Is the SN74ALVC7806-40DL pin-compatible with older ACT-family FIFOs?

Yes, the SN74ALVC7806-40DL is explicitly stated as pin-to-pin compatible with SN74ACT7804, SN74ACT7806, and SN74ACT7814. All share identical 56-pin DL package footprint, pin assignments, and functional terminal definitions-enabling direct replacement in existing ACT-based designs while upgrading to 3.3-V operation and lower power.

What happens to the Q outputs during reset of the SN74ALVC7806-40DL?

During RESET assertion (low), the SN74ALVC7806-40DL resets internal write/read pointers and sets FULL high, EMPTY low, HF low, and AF/AE high-but the Q0–Q17 outputs retain their last valid logic states and are not forced to any defined level. Outputs remain in their pre-reset state until the first valid UNCK rising edge after RESET deassertion, at which point newly read data appears.

Does the SN74ALVC7806-40DL require external pull-up resistors on status flags?

No, the SN74ALVC7806-40DL drives FULL, EMPTY, HF, and AF/AE flags actively high or low with CMOS-compatible output strength (±8 mA/±16 mA). These outputs are push-pull and do not require external pull-ups. However, OE must be actively driven low to enable Q0–Q17 outputs; leaving OE floating results in high-impedance outputs and undefined bus states.