Texas Instruments LP2995MR/NOPB

Overview

LP2995MR/NOPB from Texas Instruments is a linear DDR termination regulator designed specifically for SSTL-2 and SSTL-3 bus termination in DDR-SDRAM systems. It delivers ±1.5A continuous and ±3A peak sink/source current, regulates VTT to VDDQ/2 (e.g., 1.25V at VDDQ = 2.5V), and provides a buffered VREF output with ±15 mV offset over load and temperature. It operates across AVIN/PVIN = 2.2–5.5V and supports remote sensing via VSENSE for improved load regulation on memory buses.

For engineers reviewing the LP2995MR/NOPB datasheet, LP2995MR/NOPB pinout, LP2995MR/NOPB application, or LP2995MR/NOPB equivalent, key selection criteria include its dual-rail input architecture (AVIN/PVIN), VSENSE-enabled remote load regulation, thermal performance in SO PowerPAD-8 (θJA = 43°C/W), and compatibility with JEDEC-compliant DDR termination topologies requiring tight VTT–VREF tracking.

Technical Context

The LP2995MR/NOPB integrates two independent op-amps: one for VREF generation (buffered VDDQ/2) and another high-speed power op-amp driving the VTT output stage with shoot-through prevention. Its internal 50 kΩ resistor divider sets VTT = VREF = VDDQ/2, and external resistors can modify scaling (e.g., VDDQ × 0.45 for SSTL-3).

VSENSE enables Kelvin-sense feedback at the bus midpoint to compensate for PCB IR drop, while separate AVIN (control circuitry) and PVIN (power stage) rails allow optimized noise isolation and thermal management-critical for stable termination under fast DDR load transients up to 3A.

Key Specifications

Pinout & Package

LP2995MR/NOPB uses the SO PowerPAD-8 (DDA) package: 4.9 mm × 3.9 mm body, 1.7 mm max height, with exposed thermal pad (EP) electrically and thermally connected to GND. The pad must be soldered to a PCB ground plane with ≥6 vias for optimal thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LP2996MR/NOPB, LP2995MR/NOPB provides lower quiescent power and simpler startup but lacks enable control; versus TPS51100DGQR, it delivers superior transient response and noise performance at the cost of higher thermal dissipation-making it optimal for space-constrained, noise-sensitive DDR2 applications.

Availability

LP2995MR/NOPB is available at Aetrix Electronics and suitable for DDR-SDRAM termination, SSTL-2 interface design, and memory module reference distribution requiring stable component supply and industrial temperature support (0°C to +125°C).

Supply support for LP2995MR/NOPB 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 DDR interface expertise and JEDEC-compliant product validation.

The LP2995MR/NOPB belongs to TI's DDR termination regulator product line, engineered specifically for JEDEC SSTL-2/SSTL-3 compliance in cost-sensitive, thermally constrained DDR-SDRAM memory subsystems.

FAQ

What is the maximum continuous output current of the LP2995MR/NOPB?

The LP2995MR/NOPB delivers ±1.5A continuous sink and source current at VTT. This rating assumes proper thermal management-specifically, mounting the SO PowerPAD-8 package to a 4-layer PCB with ≥6 thermal vias to GND and ambient temperature ≤70°C. At higher ambient or reduced copper area, derating per θJA = 43°C/W is required. Peak transient capability remains ±3A regardless of thermal conditions.

How does the VSENSE pin improve regulation accuracy in LP2995MR/NOPB applications?

The VSENSE pin on the LP2995MR/NOPB enables remote Kelvin sensing at the DDR bus midpoint, directly compensating for IR voltage drop across PCB traces. When connected to the center of the termination plane, it reduces VTT regulation error from >40 mV (with local sensing) to <10 mV across full load range-critical for meeting SSTL-2 timing margins at 400 MT/s. If unused, VSENSE must be tied to VTT.

Can LP2995MR/NOPB be used for SSTL-3 termination, and how is the reference voltage adjusted?

Yes, LP2995MR/NOPB supports SSTL-3 by modifying the internal VDDQ/2 scaling. Adding an 11.1 kΩ resistor in series with the VDDQ pin changes the effective divider ratio from 0.5 to 0.45, yielding VREF = VTT = VDDQ × 0.45 (e.g., 0.81V at VDDQ = 1.8V). This configuration is validated in TI application note SNVA227 and maintains full LP2995MR/NOPB functionality including VSENSE and current capability.

What is the purpose of separate AVIN and PVIN pins on the LP2995MR/NOPB?

AVIN powers the internal op-amps and reference circuitry, while PVIN supplies only the high-current VTT output stage. This separation isolates noise-sensitive analog blocks from switching-induced ripple on the power rail-improving PSRR by >30 dB and preventing VREF perturbation during large VTT transients. For 2.5V/3.3V systems, AVIN and PVIN are typically tied together with a shared 10 µF ceramic capacitor near PVIN.

What package type and thermal characteristics define the LP2995MR/NOPB?

LP2995MR/NOPB uses the SO PowerPAD-8 (DDA) package: 4.9 mm × 3.9 mm body with exposed thermal pad (EP) connected to GND. Its thermal resistance is θJA = 43°C/W on a standard JEDEC 4-layer board-2.5× lower than SOIC-8 (151°C/W). This allows sustained ±1.5A operation at 70°C ambient without airflow, making it ideal for dense memory modules where thermal headroom is limited.