Texas Instruments LP2996M-TI

Overview

LP2996M-TI from Texas Instruments (formerly National Semiconductor) is a linear DDR termination regulator designed specifically for JEDEC SSTL-2 compliant DDR-I/DDR-II memory systems. It delivers ±1.5A continuous and ±3A transient sourcing/sinking capability, regulates VTT to VDDQ/2 with ≤25 mV output offset, and provides buffered VREF for chipset/DIMM reference. It serves as the core termination voltage source on memory channel motherboards.

For engineers reviewing the LP2996M-TI datasheet, LP2996M-TI pinout, LP2996M-TI application, or LP2996M-TI equivalent, key selection criteria include VTT load regulation accuracy under ±1.5A transients, VSENSE-enabled remote sensing for bus-wide voltage uniformity, STR-compatible active-low shutdown with VREF retention, thermal performance in SO-8 package (θJA = 151°C/W), and compatibility with 2.5V/1.8V VDDQ rails.

Technical Context

The LP2996M-TI implements a dual-rail linear topology: AVIN powers analog control circuitry (including error amplifier and reference divider), while PVIN supplies the high-current output stage-enabling independent optimization of noise immunity and power delivery. Its internal 50kΩ/50kΩ resistor divider on VDDQ generates a precise VDDQ/2 reference, ensuring VTT tracks memory rail voltage changes.

VSENSE enables remote feedback at the midpoint of the VTT distribution plane, correcting IR drop across long PCB traces; the SD pin asserts active-low shutdown to tri-state VTT while maintaining VREF output and reducing quiescent current to ≤150 µA-critical for Suspend-to-RAM power states.

Key Specifications

Pinout & Package

LP2996M-TI is packaged in an 8-pin SOIC (SO-8, NS Package M08A) with exposed pad not present-thermal path relies on PCB copper area and vias. Pin functions are electrically identical across SO-8 and PSOP-8 variants per National Semiconductor documentation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar DDR termination regulator applications.

Compared with LP2996M-TI, LP2997M-TI offers better thermal performance and DDR-II-specific tuning but sacrifices VDDQ voltage flexibility; TPS51100DGQ-TI eliminates linear losses entirely but introduces switching noise, component count, and no integrated VREF-making LP2996M-TI optimal for cost-sensitive, noise-sensitive, or legacy DDR-I/II designs needing plug-and-play termination.

Availability

LP2996M-TI is available at Aetrix Electronics and suitable for DDR-I memory termination, SSTL-2 bus design, and HSTL interface applications requiring stable component supply, long-term lifecycle support, and consistent electrical performance across production batches.

Supply support for LP2996M-TI 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 acquired National Semiconductor in 2011 and maintains full technical support, datasheet archives, and manufacturing continuity for legacy power management ICs including the LP2996 family.

The LP2996M-TI belongs to TI's DDR termination regulator product line, engineered specifically for JEDEC-compliant memory interface power delivery-emphasizing precision tracking, transient response, and system-level power state management (e.g., Suspend-to-RAM).

FAQ

What is the maximum continuous output current specification for the LP2996M-TI?

The LP2996M-TI delivers ±1.5 A continuous sourcing and sinking current at VTT. This rating assumes proper thermal management-specifically, θJA ≤ 151°C/W (SO-8 on 2-layer board) and ambient temperature ≤ 70°C. At higher temperatures or poorer heatsinking, derating is required per the thermal dissipation equations in the datasheet. The LP2996M-TI also supports ±3 A transient peaks for short durations without regulation loss.

How does the VSENSE pin improve regulation accuracy in motherboard applications using the LP2996M-TI?

The VSENSE pin on the LP2996M-TI enables remote feedback by connecting to the midpoint of the VTT distribution plane-compensating for IR drop across long PCB traces. In motherboard layouts where VTT traces exceed 100 mm, this reduces voltage error at far-end DIMMs from >50 mV to <10 mV. The LP2996M-TI's internal error amplifier actively adjusts VTT based on VSENSE, ensuring all memory devices see the same termination voltage regardless of physical location.

Can the LP2996M-TI be used for DDR-II memory systems, and what are the critical configuration requirements?

Yes, the LP2996M-TI supports DDR-II termination by setting VDDQ = 1.8 V to generate VTT = 0.9 V and VREF = 0.9 V. Critical configuration requirements include connecting PVIN to 1.8 V (for optimal efficiency) or 2.5 V (for higher current headroom), routing VDDQ directly from the DIMM-side 1.8 V rail for accurate tracking, and using VSENSE at the bus center. Note that for new DDR-II designs, TI recommends LP2997M-TI due to its enhanced thermal performance and DDR-II-specific tuning.

What happens to the VREF output during shutdown mode of the LP2996M-TI?

During shutdown mode-activated by pulling the SD pin low-the VREF output remains fully active and regulated at VDDQ/2, while the VTT output is tri-stated to high impedance. This behavior is essential for Suspend-to-RAM (STR) functionality, allowing the memory controller to retain reference voltage for fast wake-up without powering the termination network. The LP2996M-TI draws only ≤150 µA quiescent current in this state, minimizing standby power consumption.

Is the LP2996M-TI pin-compatible with other packages like PSOP-8 or LLP-16, and how do their thermal characteristics differ?

The LP2996M-TI (SO-8) shares identical pin functions and electrical behavior with LP2996MR (PSOP-8) and LP2996LQ (LLP-16), but pin numbering differs across packages-SO-8 and PSOP-8 use the same mapping, while LLP-16 has distinct pin locations. Thermally, SO-8 has θJA = 151°C/W, PSOP-8 achieves 43°C/W, and LLP-16 reaches 51°C/W (with 4 vias). Thus, PSOP-8 offers superior thermal performance for high-current applications, while SO-8 remains suitable for cost-sensitive, lower-power DDR-I implementations.