Texas Instruments SN74LVT2952DBR

Overview

SN74LVT2952DBR from Texas Instruments is an octal bus transceiver and register IC designed for 3.3-V V_CC operation with mixed-mode 5-V input/output compatibility. It features dual 8-bit back-to-back registers, clock-enable and output-enable control per direction, bus-hold inputs, and operates from −40°C to 85°C. It enables bidirectional data flow between A and B buses in high-speed digital systems such as backplane interfaces and memory-mapped I/O bridges.

For engineers reviewing the SN74LVT2952DBR datasheet, SN74LVT2952DBR pinout, SN74LVT2952DBR application, or SN74LVT2952DBR equivalent, key selection considerations include its 150-MHz clock frequency, 3.3-V supply with 2.7–3.6-V operating range, bus-hold functionality eliminating external pullups, and DB-package footprint optimized for space-constrained PCB layouts.

Technical Context

The SN74LVT2952DBR implements two independent 8-bit register paths (A→B and B→A), each controlled by dedicated clock (CLKAB/CLKBA), clock-enable (CLKENAB/CLKENBA), and output-enable (OEAB/OEBA) signals. Data latching occurs on the low-to-high transition of the respective clock when its enable is asserted low.

It uses Advanced BiCMOS Technology (ABT) for low-static power dissipation and supports live insertion via bus-hold circuitry that maintains valid logic levels on floating inputs. The device tolerates 5-V inputs while powered from 3.3-V V_CC, enabling seamless interfacing between 3.3-V logic and legacy 5-V subsystems without level shifters.

Key Specifications

Pinout & Package

SN74LVT2952DBR is housed in a 28-pin Shrink Small-Outline (DB) package (JEDEC MO-150 compliant), measuring 12.90 mm × 7.90 mm × 2.40 mm with 0.65-mm lead pitch. The package provides compact board area versus standard SOIC while retaining full pin compatibility across DB/DW/PW variants.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal bus transceiver applications.

Compared with SN74LVTH245DBR and SN74ALVC16245DGGR, the SN74LVT2952DBR uniquely combines clocked registration, dual-direction independent control, and 5-V-tolerant I/O in a space-efficient DB package - making it irreplaceable in synchronous mixed-voltage bridging where data capture timing and domain isolation are critical.

Availability

SN74LVT2952DBR is available at Aetrix Electronics and suitable for industrial backplane interfaces, embedded subsystem bridges, and hot-swappable module interconnects requiring stable component supply across extended product lifecycles.

Supply support for SN74LVT2952DBR 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 technologies, with decades of heritage in high-reliability interface IC design.

The SN74LVT2952DBR belongs to TI's LVT (Low-Voltage BiCMOS Transceiver) family, engineered for robust mixed-signal interoperability in industrial, telecom, and computing infrastructure where voltage-domain bridging and timing precision are essential.

FAQ

What is the maximum clock frequency supported by the SN74LVT2952DBR?

The SN74LVT2952DBR supports a maximum clock frequency of 150 MHz under recommended operating conditions (V_CC = 3.3 V ± 0.3 V). This specification is guaranteed across the full commercial temperature range (−40°C to 85°C) and enables high-speed synchronous data transfer between A and B buses without violating setup or hold timing windows.

Does the SN74LVT2952DBR require external pullup resistors on its data inputs?

No, the SN74LVT2952DBR does not require external pullup resistors on A or B port inputs due to integrated bus-hold circuitry. Each input actively maintains its last-valid logic state with ±75 µA hold current at V_CC = 3 V, eliminating floating nodes and simplifying PCB layout - a key advantage over non-bus-hold transceivers like the SN74LVTH245DBR.

Can the SN74LVT2952DBR operate with a 2.7-V supply?

Yes, the SN74LVT2952DBR is fully characterized for operation from 2.7 V to 3.6 V. At V_CC = 2.7 V, it maintains functional timing (e.g., t_su ≥ 2.5 ns, f_clock ≥ 150 MHz) and electrical performance (I_OL ≥ 48 mA), making it suitable for battery-powered systems where supply voltage may sag below nominal 3.3 V.

What is the purpose of the NC pins on the SN74LVT2952DBR DB package?

Pins 25–28 on the SN74LVT2952DBR are designated NC (No internal connection) and must remain unconnected in the PCB layout. These pins have no internal bonding or circuit connection - routing traces or applying solder paste to them risks mechanical stress or unintended parasitic coupling, and violates TI's recommended assembly practice per SCBS152E datasheet.

How does the SN74LVT2952DBR handle power-up sequencing to avoid bus contention?

To ensure high-impedance outputs during power-up or power-down, OEAB and OEBA must be tied to V_CC through pullup resistors. The minimum resistor value is determined by the driver's current-sinking capability; TI recommends values ≥10 kΩ. This prevents unintended driving of the A or B bus before system control logic initializes - a critical safeguard absent in non-OE-gated transceivers.