Texas Instruments LP2996MRX

Overview

LP2996MRX from Texas Instruments is a linear DDR termination regulator designed for VTT bus regulation in DDR1–DDR3L memory systems. It delivers ±1.5-A continuous and ±3-A peak sink/source current, regulates VTT precisely to VDDQ/2 (e.g., 0.75 V at VDDQ = 1.5 V), features active-low shutdown with Suspend-to-RAM support, and maintains stable operation with ceramic output capacitors. It is used in high-speed memory subsystems requiring JEDEC-compliant SSTL-2/3 and HSTL termination.

For engineers reviewing the LP2996MRX datasheet, LP2996MRX pinout, LP2996MRX application, or LP2996MRX equivalent, this page provides verified technical context, exact pin functions, DDR-generation-specific voltage tracking behavior, thermal derating guidance, and validated alternative options for DDR termination design.

Technical Context

The LP2996MRX implements a dual-rail linear topology: AVIN powers analog control circuitry (2.2–5.5 V), while PVIN supplies the output stage (≤AVIN), enabling thermal optimization. Its internal 50-kΩ/50-kΩ resistor divider generates VREF = VDDQ/2, which directly sets VTT regulation target - confirmed across DDR I (VDDQ = 2.5 V → VTT = 1.259 V), DDR II (VDDQ = 1.8 V → VTT = 0.908 V), and DDR III (VDDQ = 1.5 V → VTT = 0.758 V).

VSENSE enables remote-sense load regulation to compensate for IR drop on long VTT planes; SD asserts low to tri-state VTT while keeping VREF active for STR mode; thermal shutdown triggers at 165°C with 10°C hysteresis. The device supports split-rail operation, eliminates external feedback resistors, and achieves fast transient response via integrated high-speed op-amp and shoot-through–protected output stage.

Key Specifications

Pinout & Package

LP2996MRX is packaged in an 8-pin SOIC (D package) with PowerPAD™ thermal pad (4.90 mm × 3.90 mm body). The exposed thermal pad must be soldered to PCB ground for optimal thermal performance (R_θJB = 36.5°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with LP2996MRX, LP2998MRE adds automotive qualification and wider temperature support but offers no performance gain in standard commercial DDR3L systems; TPS51100DGQR improves efficiency but sacrifices noise performance and ease of use - LP2996MRX remains optimal for cost-sensitive, noise-critical, single-rail DDR termination.

Availability

LP2996MRX is available at Aetrix Electronics and suitable for DDR3L memory subsystems, industrial motherboards, medical PCs, and FPGA-based embedded systems requiring stable component supply and JEDEC-compliant termination voltage regulation.

Supply support for LP2996MRX 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 specializing in analog, embedded processing, and digital signal processing technologies, with decades of leadership in power management ICs.

The LP2996MRX belongs to TI's DDR termination regulator product line, engineered specifically for JEDEC-compliant VTT generation in DDR1–DDR3L memory interfaces - emphasizing precision tracking, low noise, and seamless integration into high-density memory subsystems.

FAQ

What is the minimum VDDQ voltage supported by the LP2996MRX?

The LP2996MRX supports a minimum VDDQ of 1.35 V, enabling full compatibility with DDR3L memory standards. At this voltage, it regulates VTT to 0.677 V (VDDQ/2) with ±30 mV offset and maintains ±0.2-A load regulation within specification. This is confirmed in the Electrical Characteristics table for DDR III operation under TJ = 0°C to 125°C.

Does the LP2996MRX require external resistors to set VTT voltage?

No, the LP2996MRX does not require external resistors to set VTT voltage. It uses an internal matched pair of 50-kΩ resistors to divide VDDQ and generate VREF = VDDQ/2, which directly controls VTT regulation. This eliminates external feedback components and ensures precise tracking across temperature and process variation - a key feature confirmed in the Functional Block Diagram and Feature Description sections.

How does the VSENSE pin improve regulation in the LP2996MRX?

The VSENSE pin in the LP2996MRX enables remote-sense feedback by connecting to the midpoint of the VTT distribution plane, compensating for IR drop along long PCB traces. With only 13 nA input bias current, it minimizes measurement error from trace leakage. When used, VSENSE improves load regulation accuracy to ±5 mV versus ±15 mV with local sensing - critical for high-pin-count DDR3L DIMMs.

What happens to VREF during LP2996MRX shutdown mode?

During LP2996MRX shutdown mode (SD pin pulled low), VREF remains fully active and continues to output VDDQ/2 (e.g., 0.752 V at VDDQ = 1.5 V) with buffered drive capability. This preserves reference integrity for chipset and DIMM circuits while VTT is tri-stated - a core requirement for Suspend-to-RAM functionality explicitly documented in the Device Functional Modes section.

Can the LP2996MRX be used for HSTL termination?

Yes, the LP2996MRX is explicitly qualified for HSTL termination per the Applications section, which lists "HSTL Termination" as a primary use case. It delivers the required VTT = 0.75 V (for HSTL-15) with ±12 mV regulation accuracy and supports the fast transient response needed for HSTL Class I interfaces - confirmed by its ±3-A peak current capability and high-speed op-amp architecture.